draft-ietf-secsh-filexfer-07.txt   draft-ietf-secsh-filexfer-08.txt 
Secure Shell Working Group J. Galbraith Secure Shell Working Group J. Galbraith
Internet-Draft VanDyke Software Internet-Draft VanDyke Software
Expires: September 25, 2005 O. Saarenmaa Expires: October 7, 2005 O. Saarenmaa
F-Secure F-Secure
T. Ylonen T. Ylonen
S. Lehtinen S. Lehtinen
SSH Communications Security Corp SSH Communications Security Corp
March 24, 2005 April 5, 2005
SSH File Transfer Protocol SSH File Transfer Protocol
draft-ietf-secsh-filexfer-07.txt draft-ietf-secsh-filexfer-08.txt
Status of this Memo Status of this Memo
This document is an Internet-Draft and is subject to all provisions This document is an Internet-Draft and is subject to all provisions
of Section 3 of RFC 3667. By submitting this Internet-Draft, each of Section 3 of RFC 3667. By submitting this Internet-Draft, each
author represents that any applicable patent or other IPR claims of author represents that any applicable patent or other IPR claims of
which he or she is aware have been or will be disclosed, and any of which he or she is aware have been or will be disclosed, and any of
which he or she become aware will be disclosed, in accordance with which he or she become aware will be disclosed, in accordance with
RFC 3668. RFC 3668.
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2005). Copyright (C) The Internet Society (2005).
Abstract Abstract
The SSH File Transfer Protocol provides secure file transfer The SSH File Transfer Protocol provides secure file transfer
functionality over any reliable data stream. It is the standard file functionality over any reliable data stream. It is the standard file
transfer protocol for use with the SSH2 protocol. This document transfer protocol for use with the SSH2 protocol. This document
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Use with the SSH Connection Protocol . . . . . . . . . . . . . 4 2. Use with the SSH Connection Protocol . . . . . . . . . . . . . 4
2.1 The Use of 'stderr' in the server . . . . . . . . . . . . 4 2.1 The Use of 'stderr' in the server . . . . . . . . . . . . 4
3. General Packet Format . . . . . . . . . . . . . . . . . . . . 5 3. General Packet Format . . . . . . . . . . . . . . . . . . . . 5
3.1 Request Synchronization and Reordering . . . . . . . . . . 6 3.1 Request Synchronization and Reordering . . . . . . . . . . 6
3.2 New data types defined by this document . . . . . . . . . 6 3.2 New data types defined by this document . . . . . . . . . 6
3.3 Packet Types . . . . . . . . . . . . . . . . . . . . . . . 7 3.3 Packet Types . . . . . . . . . . . . . . . . . . . . . . . 7
4. Protocol Initialization . . . . . . . . . . . . . . . . . . . 8 4. Protocol Initialization . . . . . . . . . . . . . . . . . . . 8
4.1 Client Initialization . . . . . . . . . . . . . . . . . . 8 4.1 Client Initialization . . . . . . . . . . . . . . . . . . 8
4.2 Server Initialization . . . . . . . . . . . . . . . . . . 8 4.2 Server Initialization . . . . . . . . . . . . . . . . . . 9
4.3 Determining Server Newline Convention . . . . . . . . . . 9 4.3 Determining Server Newline Convention . . . . . . . . . . 9
4.4 Supported Features . . . . . . . . . . . . . . . . . . . . 9 4.4 Vendor Id . . . . . . . . . . . . . . . . . . . . . . . . 9
4.5 Version re-negotiation . . . . . . . . . . . . . . . . . . 11 4.5 Supported Features . . . . . . . . . . . . . . . . . . . . 10
5. File Names . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.6 Version re-negotiation . . . . . . . . . . . . . . . . . . 12
6. File Attributes . . . . . . . . . . . . . . . . . . . . . . . 13 5. File Names . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6.1 valid-attribute-flags . . . . . . . . . . . . . . . . . . 14 6. File Attributes . . . . . . . . . . . . . . . . . . . . . . . 15
6.2 Type . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 6.1 valid-attribute-flags . . . . . . . . . . . . . . . . . . 16
6.3 Size . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 6.2 Type . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.4 allocation-size . . . . . . . . . . . . . . . . . . . . . 16 6.3 Size . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.5 Owner and Group . . . . . . . . . . . . . . . . . . . . . 16 6.4 allocation-size . . . . . . . . . . . . . . . . . . . . . 18
6.6 Permissions . . . . . . . . . . . . . . . . . . . . . . . 17 6.5 Owner and Group . . . . . . . . . . . . . . . . . . . . . 18
6.7 Times . . . . . . . . . . . . . . . . . . . . . . . . . . 17 6.6 Permissions . . . . . . . . . . . . . . . . . . . . . . . 19
6.8 ACL . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 6.7 Times . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.9 attrib-bits . . . . . . . . . . . . . . . . . . . . . . . 19 6.8 ACL . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.10 Text Hint . . . . . . . . . . . . . . . . . . . . . . . . 22 6.9 attrib-bits and attrib-bits-valid . . . . . . . . . . . . 21
6.11 Mime type . . . . . . . . . . . . . . . . . . . . . . . . 22 6.10 text-hint . . . . . . . . . . . . . . . . . . . . . . . . 24
6.12 Link Count . . . . . . . . . . . . . . . . . . . . . . . . 22 6.11 mime-type . . . . . . . . . . . . . . . . . . . . . . . . 24
6.13 Extended Attributes . . . . . . . . . . . . . . . . . . . 22 6.12 link-count . . . . . . . . . . . . . . . . . . . . . . . . 24
7. Requests From the Client to the Server . . . . . . . . . . . . 23 6.13 untranslated-name . . . . . . . . . . . . . . . . . . . . 25
7.1 Opening and Closing Files and Directories . . . . . . . . 23 6.14 Extended Attributes . . . . . . . . . . . . . . . . . . . 25
7.1.1 Opening a File . . . . . . . . . . . . . . . . . . . . 23 7. Requests From the Client to the Server . . . . . . . . . . . . 25
7.1.2 Opening a Directory . . . . . . . . . . . . . . . . . 28 7.1 Opening and Closing Files and Directories . . . . . . . . 25
7.1.3 Closing Handles . . . . . . . . . . . . . . . . . . . 29 7.1.1 Opening a File . . . . . . . . . . . . . . . . . . . . 26
7.2 Reading and Writing . . . . . . . . . . . . . . . . . . . 29 7.1.2 Opening a Directory . . . . . . . . . . . . . . . . . 31
7.2.1 Reading Files . . . . . . . . . . . . . . . . . . . . 29 7.1.3 Closing Handles . . . . . . . . . . . . . . . . . . . 32
7.2.2 Reading Directories . . . . . . . . . . . . . . . . . 30 7.2 Reading and Writing . . . . . . . . . . . . . . . . . . . 32
7.2.3 Writing Files . . . . . . . . . . . . . . . . . . . . 30 7.2.1 Reading Files . . . . . . . . . . . . . . . . . . . . 32
7.3 Removing and Renaming Files . . . . . . . . . . . . . . . 31 7.2.2 Reading Directories . . . . . . . . . . . . . . . . . 33
7.4 Creating and Deleting Directories . . . . . . . . . . . . 32 7.2.3 Writing Files . . . . . . . . . . . . . . . . . . . . 33
7.5 Retrieving File Attributes . . . . . . . . . . . . . . . . 33 7.3 Removing and Renaming Files . . . . . . . . . . . . . . . 34
7.6 Setting File Attributes . . . . . . . . . . . . . . . . . 34 7.4 Creating and Deleting Directories . . . . . . . . . . . . 35
7.7 Dealing with Links . . . . . . . . . . . . . . . . . . . . 35 7.5 Retrieving File Attributes . . . . . . . . . . . . . . . . 36
7.8 Canonicalizing the Server-Side Path Name . . . . . . . . . 36 7.6 Setting File Attributes . . . . . . . . . . . . . . . . . 37
7.8.1 Best Practice for Dealing with Paths . . . . . . . . . 37 7.7 Dealing with Links . . . . . . . . . . . . . . . . . . . . 38
8. Responses from the Server to the Client . . . . . . . . . . . 38 7.8 Canonicalizing the Server-Side Path Name . . . . . . . . . 40
9. Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . 44 7.8.1 Best Practice for Dealing with Paths . . . . . . . . . 42
9.1 File Hashing . . . . . . . . . . . . . . . . . . . . . . . 45 8. Responses from the Server to the Client . . . . . . . . . . . 42
9.1.1 Checking File Contents: v5 extension . . . . . . . . . 46 8.1 Status Response . . . . . . . . . . . . . . . . . . . . . 43
9.1.2 Checking File Contents . . . . . . . . . . . . . . . . 47 8.2 Handle Response . . . . . . . . . . . . . . . . . . . . . 47
9.2 Querying Available Space . . . . . . . . . . . . . . . . . 48 8.3 Data Response . . . . . . . . . . . . . . . . . . . . . . 47
9.3 Querying User Home Directory . . . . . . . . . . . . . . . 49 8.4 Name Response . . . . . . . . . . . . . . . . . . . . . . 48
10. Implementation Considerations . . . . . . . . . . . . . . . 50 8.5 Attrs Response . . . . . . . . . . . . . . . . . . . . . . 49
11. Security Considerations . . . . . . . . . . . . . . . . . . 50 9. Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . 49
12. Changes from Previous Protocol Versions . . . . . . . . . . 52 9.1 File Hashing . . . . . . . . . . . . . . . . . . . . . . . 50
12.1 Changes Between Versions 6 and 5 . . . . . . . . . . . . . 52 9.1.1 Checking File Contents: v5 extension . . . . . . . . . 51
12.2 Changes Between Versions 5 and 4 . . . . . . . . . . . . . 52 9.1.2 Checking File Contents . . . . . . . . . . . . . . . . 52
12.3 Changes Between Versions 4 and 3 . . . . . . . . . . . . . 53 9.2 Querying Available Space . . . . . . . . . . . . . . . . . 54
12.4 Changes Between Versions 3 and 2 . . . . . . . . . . . . . 54 9.3 Querying User Home Directory . . . . . . . . . . . . . . . 55
12.5 Changes Between Versions 2 and 1 . . . . . . . . . . . . . 54 10. Implementation Considerations . . . . . . . . . . . . . . . 55
12.6 Changes Between Versions 1 and 0 . . . . . . . . . . . . . 54 11. Security Considerations . . . . . . . . . . . . . . . . . . 56
13. Trademark Issues . . . . . . . . . . . . . . . . . . . . . . 54 12. Changes from Previous Protocol Versions . . . . . . . . . . 57
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 54 12.1 Changes Between Versions 6 and 5 . . . . . . . . . . . . . 57
14.1 Normative References . . . . . . . . . . . . . . . . . . . 54 12.2 Changes Between Versions 5 and 4 . . . . . . . . . . . . . 58
14.2 Informative References . . . . . . . . . . . . . . . . . . 55 12.3 Changes Between Versions 4 and 3 . . . . . . . . . . . . . 59
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 55 12.4 Changes Between Versions 3 and 2 . . . . . . . . . . . . . 59
Intellectual Property and Copyright Statements . . . . . . . . 57 12.5 Changes Between Versions 2 and 1 . . . . . . . . . . . . . 59
12.6 Changes Between Versions 1 and 0 . . . . . . . . . . . . . 59
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 60
13.1 Normative References . . . . . . . . . . . . . . . . . . . 60
13.2 Informative References . . . . . . . . . . . . . . . . . . 61
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 61
Intellectual Property and Copyright Statements . . . . . . . . 63
1. Introduction 1. Introduction
This protocol provides secure file transfer (and more generally file This protocol provides secure file transfer (and more generally file
system access.) It is designed so that it could be used to implement system access.) It is designed so that it could be used to implement
a secure remote file system service, as well as a secure file a secure remote file system service, as well as a secure file
transfer service. transfer service.
This protocol assumes that it runs over a secure channel, such as a This protocol assumes that it runs over a secure channel, such as a
channel in [I-D.ietf-secsh-architecture]. and that the server has channel in [I-D.ietf-secsh-architecture]. and that the server has
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request that the server is responding to. One possible request that the server is responding to. One possible
implementation is for the client to us a monotonically increasing implementation is for the client to us a monotonically increasing
request sequence number (modulo 2^32). There is, however, no request sequence number (modulo 2^32). There is, however, no
particular requirement the 'request-id' fields be unique. particular requirement the 'request-id' fields be unique.
There are two packets, INIT and VERSION, which do not use the There are two packets, INIT and VERSION, which do not use the
request-id. request-id.
Packet descriptions in this document will contain the 'request-id' Packet descriptions in this document will contain the 'request-id'
field, but will not redefine it. field, but will not redefine it.
Implementations MUST ignore excess data after an otherwise valid Implementations MUST ignore excess data at the end of an otherwise
packet. Implementation MUST respond to unrecognized packet types valid packet. Implementations MUST respond to unrecognized packet
with an SSH_FX_OP_UNSUPPORTED error. This will allow the protocol to types with an SSH_FX_OP_UNSUPPORTED error. This will allow the
be extended in a backwards compatible way as needed. protocol to be extended in a backwards compatible way as needed.
There is no limit on the number of outstanding (non-acknowledged) There is no limit on the number of outstanding (non-acknowledged)
requests that the client may send to the server. In practice this is requests that the client may send to the server. In practice this is
limited by the buffering available on the data stream and the queuing limited by the buffering available on the data stream and the queuing
performed by the server. If the server's queues are full, it should performed by the server. If the server's queues are full, it should
not read any more data from the stream, and flow control will prevent not read any more data from the stream, and flow control will prevent
the client from sending more requests. Note, however, that while the client from sending more requests. Note, however, that while
there is no restriction on the protocol level, the client's API may there is no restriction on the protocol level, the client's API may
provide a limit in order to prevent infinite queuing of outgoing provide a limit in order to prevent infinite queuing of outgoing
requests at the client. requests at the client.
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server must ensure fairness in the sense that processing of no server must ensure fairness in the sense that processing of no
request will be indefinitely delayed even if the client is sending request will be indefinitely delayed even if the client is sending
other requests so that there are multiple outstanding requests all other requests so that there are multiple outstanding requests all
the time. the time.
A client MUST be prepared to recieve responses to multiple overlapped A client MUST be prepared to recieve responses to multiple overlapped
requests out of order. requests out of order.
3.2 New data types defined by this document 3.2 New data types defined by this document
This document defines several data types in addition to those defined This document defines these data types in addition to those defined
in [I-D.ietf-secsh-architecture]. in [I-D.ietf-secsh-architecture].
int64 int64
Represents a 64-bit signed integer. Stored as eight bytes in the Represents a 64-bit signed integer. Stored as eight bytes in the
order of decreasing significance (network byte order). order of decreasing significance (network byte order).
extension-pair extension-pair
string extension-name string extension-name
string extension-data string extension-data
'extension-name' is the name of a protocol extension. Extensions 'extension-name' is the name of a protocol extension. Extensions
not defined by IETF consensus MUST follow the the DNS not defined by IETF CONSENSUS MUST follow the the DNS
extensibility naming convention outlined in extensibility naming convention outlined in [I-D.ietf-secsh-
[I-D.ietf-secsh-architecture]. architecture].
'extension-data' is any data specific to the extension, and MAY be 'extension-data' is any data specific to the extension, and MAY be
zero length if the extension has no data. zero length if the extension has no data.
3.3 Packet Types 3.3 Packet Types
The following values are defined for packet types. The following values are defined for packet types.
SSH_FXP_INIT 1 SSH_FXP_INIT 1
SSH_FXP_VERSION 2 SSH_FXP_VERSION 2
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SSH_FXP_OPENDIR 11 SSH_FXP_OPENDIR 11
SSH_FXP_READDIR 12 SSH_FXP_READDIR 12
SSH_FXP_REMOVE 13 SSH_FXP_REMOVE 13
SSH_FXP_MKDIR 14 SSH_FXP_MKDIR 14
SSH_FXP_RMDIR 15 SSH_FXP_RMDIR 15
SSH_FXP_REALPATH 16 SSH_FXP_REALPATH 16
SSH_FXP_STAT 17 SSH_FXP_STAT 17
SSH_FXP_RENAME 18 SSH_FXP_RENAME 18
SSH_FXP_READLINK 19 SSH_FXP_READLINK 19
SSH_FXP_LINK 21 SSH_FXP_LINK 21
SSH_FXP_BLOCK 22
SSH_FXP_UNBLOCK 23
SSH_FXP_STATUS 101 SSH_FXP_STATUS 101
SSH_FXP_HANDLE 102 SSH_FXP_HANDLE 102
SSH_FXP_DATA 103 SSH_FXP_DATA 103
SSH_FXP_NAME 104 SSH_FXP_NAME 104
SSH_FXP_ATTRS 105 SSH_FXP_ATTRS 105
SSH_FXP_EXTENDED 200 SSH_FXP_EXTENDED 200
SSH_FXP_EXTENDED_REPLY 201 SSH_FXP_EXTENDED_REPLY 201
RESERVED_FOR_EXTENSIONS 210-255
Additional packet types should only be defined if the protocol SSH_FXP_EXTENDED and SSH_FXP_EXTENDED_REPLY packets can be used to
version number (see Section ''Protocol Initialization'') is implement extensions, which can be vendor specific. See Section
incremented, and their use MUST be negotiated using the version ''Extensions'' for more details.
number. However, the SSH_FXP_EXTENDED and SSH_FXP_EXTENDED_REPLY
packets can be used to implement extensions, which can be vendor Values 210-255 are reserved for use in conjunction with these
specific. See Section ''Extensions'' for more details. extensions. The SSH_FXP_EXTENDED packet can be used to negotiate the
meaning of these reserved types. It is suggested that the actual
value to be used also be negotiated, since this will prevent
collision among multiple uncoordinated extensions.
The server MUST respond with SSH_FXP_STATUS(SSH_FX_OP_UNSUPPORTED) if
it receives a packet it does not recognize. The protocol version
(Section 4) MUST be incremented if the server is to send new packets
to the client (because the client has no way to respond indicating
that the packet isn't recognized.)
4. Protocol Initialization 4. Protocol Initialization
When the file transfer protocol starts, the client first sends a When the file transfer protocol starts, the client first sends a
SSH_FXP_INIT (including its version number) packet to the server. SSH_FXP_INIT (including its version number) packet to the server.
The server responds with a SSH_FXP_VERSION packet, supplying the The server responds with a SSH_FXP_VERSION packet, supplying the
lowest of its own and the client's version number. Both parties lowest of its own and the client's version number. Both parties
should from then on adhere to particular version of the protocol. should from then on adhere to that particular version of the
protocol.
The version number of the protocol specified in this document is 6. The version number of the protocol specified in this document is 6.
The version number should be incremented for each incompatible The version number should be incremented for each incompatible
revision of this protocol. revision of this protocol.
Note that these two packets DO NOT contain a request id. These are Note that these two packets DO NOT contain a request id. These are
the only such packets in the protocol. the only such packets in the protocol.
4.1 Client Initialization 4.1 Client Initialization
The SSH_FXP_INIT packet (from client to server) has the following The SSH_FXP_INIT packet (from client to server) has the following
data: data:
uint32 version uint32 version
'version' is the version number of the client. If the client wishes 'version' is the version number of the client. If the client wishes
to interoperate with servers that support dis-contigous version to interoperate with servers that support discontiguous version
numbers it SHOULD send '3', and then use the 'version-select' numbers it SHOULD send '3', and then use the 'version-select'
extension (see below.) Otherwise, this value is '6' for this version extension (see below.) Otherwise, this value is '6' for this version
of the protocol. of the protocol.
4.2 Server Initialization 4.2 Server Initialization
The SSH_FXP_VERSION packet (from server to client) has the following The SSH_FXP_VERSION packet (from server to client) has the following
data: data:
uint32 version uint32 version
extension-pair extensions[0..n] extension-pair extensions[0..n]
'version' is the lower of the protocol version supported by the 'version' is the lower of the protocol version supported by the
server and the version number received from the client. server and the version number received from the client.
'extensions' is 0 or more extension-pairs (Section 3.2). 'extensions' is 0 or more extension-pairs (Section 3.2).
Implementations MUST silently ignore any extensions whose name they Implementations MUST silently ignore any extensions whose names they
do not recognize. do not recognize.
4.3 Determining Server Newline Convention 4.3 Determining Server Newline Convention
In order to correctly process text files in a cross platform In order to correctly process text files in a cross platform
compatible way, newline sequences must be converted between client compatible way, newline sequences must be converted between client
and server conventions. and server conventions.
The SSH_FXF_TEXT file open flag (Section 7.1.1) makes it possible to The SSH_FXF_TEXT file open flag (Section 7.1.1) makes it possible to
request that the server translate a file to a 'canonical' wire request that the server translate a file to a 'canonical' wire
format. This format uses \r\n as the line separator. format. This format uses CRLF as the line separator.
Servers for systems using multiple newline characters (for example, Servers for systems using other conventions MUST translate to and
Mac OS X or VMS) or systems using counted records, MUST translate to from the canonical form.
the canonical form.
However, to ease the burden of implementation on servers that use a However, to ease the burden of implementation on servers that use a
single, simple, separator sequence the following extension allows the single, simple, separator sequence the following extension allows the
canonical format to be changed. canonical format to be changed.
string "newline" string "newline"
string new-canonical-separator (usually "\r" or "\n" or "\r\n") string new-canonical-separator (usually CR or LF or CRLF)
All clients MUST support this extension. All clients MUST support this extension.
When processing text files, clients SHOULD NOT translate any When processing text files, clients SHOULD NOT translate any
character or sequence that is not an exact match of the server's character or sequence that is not an exact match of the server's
newline separator. newline separator.
In particular, if the newline sequence being used is the canonical In particular, if the newline sequence being used is the canonical
"\r\n" sequence, a lone "\r" or a lone "\n" SHOULD be written through CRLF sequence, a lone CR or a lone LF SHOULD be written through
without change. without change.
4.4 Supported Features 4.4 Vendor Id
It is often necessary to detect the version of a the server so that
bugs can be worked around. This extension allows the client to do
so. (It may also be sent by the client using an EXTENDED request.
string "vendor-id"
string vendor-structure
string vendor-name
string product-name
string product-version
uint64 product-build-number
vendor-name
Arbitrary name identifying the maker of the product.
product-name
Arbitrary name identifying the product.
product-name
Arbitrary string identifying the version of the product.
product-build-number
A build-number for the product, such that if a bug is fixed in
build-number 'x', it can be assumed that (barring regression in
the product) it is fixed in all build-numbers > 'x'.
4.5 Supported Features
The sftp protocol has grown to be very rich, and now supports a The sftp protocol has grown to be very rich, and now supports a
number of features that may not be available on all servers. number of features that may not be available on all servers.
When a server receives a request for a feature it cannot support, it When a server receives a request for a feature it cannot support, it
MUST return a SSH_FX_OP_UNSUPPORTED status code, unless otherwise MUST return a SSH_FX_OP_UNSUPPORTED status code, unless otherwise
specified. In order to facilitate clients being able to use the specified. The following extension facilitates clients being able to
maximum available feature set, and yet not be overly burdened by use the maximum available feature set, and yet not be overly burdened
dealing with SSH_FX_OP_UNSUPPORTED status codes, the following by dealing with SSH_FX_OP_UNSUPPORTED status codes. All servers MUST
extension which all servers MUST include as part of their version include as part of their version packet.
packet, is introduced.
string "supported2" string "supported2"
string supported-structure string supported-structure
uint32 supported-attribute-mask uint32 supported-attribute-mask
uint32 supported-attribute-bits uint32 supported-attribute-bits
uint32 supported-open-flags uint32 supported-open-flags
uint32 max-read-size uint32 max-read-size
string extension-names[0..n] uint64 supported-open-block-masks
uint64 supported-block-masks
uint32 attrib-extension-count
string attrib-extension-names[attrib_extension-count]
uint32 extension-count
string extension-names[extension-count]
Note that the name "supported2" is used here to avoid conflict with
the slightly different "supported" extension that was previously
used.
supported-attribute-mask supported-attribute-mask
This mask MAY by applied to the 'File Attributes' This mask MAY by applied to the 'File Attributes' valid-attribute-
valid-attribute-flags field (Section 6.1) to ensure that no flags field (Section 6.1) to ensure that no unsupported attributes
unsupported attributes are present during a operation which writes are present during a operation which writes attributes.
attributes.
supported-attribute-bits supported-attribute-bits
This mask MAY by applied to the 'File Attributes' attrib-bits This mask MAY by applied to the 'File Attributes' attrib-bits
field (Section 6.9) to ensure that no unsupported attrib-bits are field (Section 6.9) to ensure that no unsupported attrib-bits are
present during a operation which writes attributes. present during a operation which writes attributes.
supported-open-flags supported-open-flags
The supported-open-flags mask MAY be applied to the SSH_FXP_OPEN The supported-open-flags mask MAY be applied to the SSH_FXP_OPEN
(Section 7.1.1) flags field. (Section 7.1.1) flags field.
max-read-size max-read-size
This is the maximum read size that the server gaurantees to This is the maximum read size that the server guarantees to
complete. For example, certain embedded server implementations complete. For example, certain embedded server implementations
only complete the first 4K of a read, even if there is additional complete only the first 4K of a read, even if there is additional
data to be read from the file. data to be read from the file.
If the server specifies a non-zero value, it MUST return at least If the server specifies a non-zero value for max-read-size, it
the max-read-size number of bytes for any read requesting MUST return the requested number of bytes for reads that are less
max-read-size bytes. Failure to return max-read-size bytes in than or equal to the value, unless it encounters EOF or an ERROR.
such a case indicates either EOF or another error condition
occurred.
extension names The server MAY use this value to express that it is willing to
The extension names may be empty (contains zero strings), or it handle very large read requests, in excess of the standard 34000
may contain any named extensions that the server wishes to bytes specfied in Section 3.
advertise.
The client must be able to differentiate between attribute supported-open-block-masks
extensions (Section 6.13) and extended requests (Section 9) by the Series of four-bit fields representing the support combinations of
extension name. SSH_FXF_ACCESS_BLOCK_READ, SSH_FXF_ACCESS_BLOCK_WRITE,
SSH_FXF_ACCESS_BLOCK_DELETE, and SSH_FXF_ACCESS_BLOCK_ADVISORY
(Section 7.1.1.3.)
The bits are interpreted in four-bit groups, beginning with the
least significant bit. The bit values are the values used in the
file open flags, shifted right so that BLOCK_READ is the least
significant bit.
For example, a server that supported only the classic advisory
read lock (shared lock) and write lock (exclusive lock) would send
0b1011 1010, or 0xba.
supported-block-masks
Series of four-bit fields representing the supported combinations
of BLOCK_* flags for use with the SSH_FXF_BLOCK request, as
described above.
attrib-extension-count
Count of extension names in the attrib-extension array.
attrib-extension-names
Names of extensions that can be used in an ATTRS (Section 6.14)
structure.
extension-count
Count of extension names in the attrib-extension array.
extension-names
Names of extensions that can be used with the SSH_FXP_EXTEND
(Section 9) packet.
Naturally, if a given attribute field, attribute mask bit, open flag, Naturally, if a given attribute field, attribute mask bit, open flag,
or extension is required for correct operation, the client MUST or extension is required for correct operation, the client MUST
either not allow the bit to be masked off, or MUST fail the operation either not allow the bit to be masked off, or MUST fail the operation
gracefully without sending the request to the server. gracefully without sending the request to the server.
The client MAY send requests that are not supported by the server; The client MAY send requests that are not supported by the server;
however, it is not normally expected to be productive to do so. The however, it is not normally expected to be productive to do so. The
client SHOULD apply the mask even to attrib structures received from client SHOULD apply the mask even to attrib structures received from
the server. The server MAY include attributes or attrib-bits that the server. The server MAY include attributes or attrib-bits that
are not included in the mask. Such attributes or attrib-bits are are not included in the mask. Such attributes or attrib-bits are
effectively read-only. effectively read-only.
4.5 Version re-negotiation 4.6 Version re-negotiation
If the server supports a higher version than was negotiated, it may If the server supports other versions than what was negotiated, it
wish to send the 'versions' extension to inform the client of this may wish to send the 'versions' extension to inform the client of
fact. The client may then optionally choose to use one of the higher this fact. The client may then optionally choose to use one of the
versions supported. other versions supported.
string "versions" string "versions"
string comma-seperated-versions string comma-separated-versions
'comma-seperated-versions' is a string of comma seperated version 'comma-separated-versions' is a string of comma separated version
numbers, for example, "3,6,7. Versions defined by are: "2", "3", numbers, for example, "3,6,7". Defined versions are: "2", "3", "4",
"4", "5", "6". Any other version advertised by the server must "5", "6". Any other version advertised by the server must follow the
follow the DNS extensibility naming convention outlined in DNS extensibility naming convention outlined in [I-D.ietf-secsh-
[I-D.ietf-secsh-architecture]. architecture].
The client may select a new version to use from the list the server If the client and server have negotiated any version higher than
provided using the following SSH_FXP_EXTENDED request. version '3' (the version at which SSH_FXP_EXTENDED was introduced) in
the initial VERSION/INIT exchange, the client may select a new
version to use from the list the server provided using the following
SSH_FXP_EXTENDED request.
string "version-select" string "version-select"
uint32 version-from-list uint32 version-from-list
If the 'version-from-list' is one of the versions on the servers If the 'version-from-list' is one of the versions on the servers
list, the server MUST respond with SSH_FX_OK. If the server did not list, the server MUST respond with SSH_FX_OK. If the server did not
send the "versions" extension, or the version-from-list was not send the "versions" extension, or the version-from-list was not
included, the server MAY send a status response describing the included, the server MAY send a status response describing the
failure, but MUST then close the channel without processing any failure, but MUST then close the channel without processing any
further requests. further requests.
The 'version-select' MUST be the first request from the client to the
server; if it is not, the server MUST fail the request and close the
channel.
Although this request does take a full round trip, no client need Although this request does take a full round trip, no client need
wait for the response before continuing, because any valid request wait for the response before continuing, because any valid request
MUST succeed, and any invalid request results in a channel close. MUST succeed, and any invalid request results in a channel close.
Since the request is the first request, it is not possible for the
server to have already sent responses conforming to the old version.
The client SHOULD NOT select a version lower than was initially
negotiated; however, it is not forbidden to do so. One reason a
client might do so is to work around a buggy implementation.
5. File Names 5. File Names
This protocol represents file names as strings. File names are This protocol represents file names as strings. File names are
assumed to use the slash ('/') character as a directory separator. assumed to use the slash ('/') character as a directory separator.
File names starting with a slash are "absolute", and are relative to File names starting with a slash are "absolute", and are relative to
the root of the file system. Names starting with any other character the root of the file system. Names starting with any other character
are relative to the user's default directory (home directory). Note are relative to the user's default directory (home directory). Note
that identifying the user is assumed to take place outside of this that identifying the user is assumed to take place outside of this
skipping to change at page 13, line 18 skipping to change at page 15, line 10
If the server included the 'filename-charset' extension with its If the server included the 'filename-charset' extension with its
VERSION packet, a client MAY send the following extension to turn off VERSION packet, a client MAY send the following extension to turn off
server translation to UTF-8. server translation to UTF-8.
string "filename-translation-control" string "filename-translation-control"
bool do-translate bool do-translate
If the client does not send this extension, the server MUST continue If the client does not send this extension, the server MUST continue
to attempt translation to UTF-8. When a client sends this extension, to attempt translation to UTF-8. When a client sends this extension,
the server MUST enable or disable filename translation according to the server MUST enable filename translation if 'do-translate' is
the value of 'do-translate' true, or disable filename translation if it is false.
The server MUST respond with a STATUS response; if the server sent a The server MUST respond with a STATUS response; if the server sent a
'filename-charset' extension, the status MUST be SUCCESS. Otherwise, 'filename-charset' extension, the status MUST be SUCCESS. Otherwise,
the status MUST be UNSUPPORTED. the status MUST be UNSUPPORTED.
When UTF-8 is sent, the shortest valid UTF-8 encoding of the UNICODE When UTF-8 is sent, the shortest valid UTF-8 encoding of the UNICODE
data MUST be used. The server is responsible for converting the data MUST be used. The server is responsible for converting the
UNICODE data to whatever canonical form it requires. For example, if UNICODE data to whatever canonical form it requires. For example, if
the server requires that precomposed characters always be used, the the server requires that precomposed characters always be used, the
server MUST NOT assume the filename as sent by the client has this server MUST NOT assume the filename as sent by the client has this
attribute, but must do this normalization itself. attribute, but must do this normalization itself.
6. File Attributes 6. File Attributes
A new compound data type is defined for encoding file attributes. A new compound data type, 'ATTRS', is defined for encoding file
The same encoding is used both when returning file attributes from attributes. The same encoding is used both when returning file
the server and when sending file attributes to the server. attributes from the server and when sending file attributes to the
server.
uint32 valid-attribute-flags uint32 valid-attribute-flags
byte type always present byte type always present
uint64 size if flag SIZE uint64 size if flag SIZE
uint64 allocation-size if flag ALLOCATION_SIZE uint64 allocation-size if flag ALLOCATION_SIZE
string owner if flag OWNERGROUP string owner if flag OWNERGROUP
string group if flag OWNERGROUP string group if flag OWNERGROUP
uint32 permissions if flag PERMISSIONS uint32 permissions if flag PERMISSIONS
int64 atime if flag ACCESSTIME int64 atime if flag ACCESSTIME
uint32 atime_nseconds if flag SUBSECOND_TIMES uint32 atime-nseconds if flag SUBSECOND_TIMES
int64 createtime if flag CREATETIME int64 createtime if flag CREATETIME
uint32 createtime_nseconds if flag SUBSECOND_TIMES uint32 createtime-nseconds if flag SUBSECOND_TIMES
int64 mtime if flag MODIFYTIME int64 mtime if flag MODIFYTIME
uint32 mtime_nseconds if flag SUBSECOND_TIMES uint32 mtime-nseconds if flag SUBSECOND_TIMES
int64 ctime if flag CTIME
uint32 ctime-nseconds if flag SUBSECOND_TIMES
string acl if flag ACL string acl if flag ACL
uint32 attrib-bits if flag BITS uint32 attrib-bits if flag BITS
uint32 attrib-bits-valid if flag BITS
byte text-hint if flag TEXT_HINT byte text-hint if flag TEXT_HINT
string mime-type if flag MIME_TYPE string mime-type if flag MIME_TYPE
uint32 link-count if flag LINK_COUNT uint32 link-count if flag LINK_COUNT
string untranslated-name if flag UNTRANSLATED_NAME string untranslated-name if flag UNTRANSLATED_NAME
uint32 extended_count if flag EXTENDED uint32 extended-count if flag EXTENDED
extended-pair extensions extended-pair extensions
6.1 valid-attribute-flags 6.1 valid-attribute-flags
The 'valid-attribute-flags' specifies which of the fields are The 'valid-attribute-flags' specifies which of the fields are
present. Those fields for which the corresponding flag is not set present. Those fields for which the corresponding flag is not set
are not present (not included in the packet). are not present (not included in the packet).
The server generally includes all attributes it knows about; however, The server generally includes all attributes it knows about; however,
it may exclude attributes that are overly expensive to retrieve it may exclude attributes that are overly expensive to retrieve
skipping to change at page 15, line 19 skipping to change at page 17, line 19
SSH_FILEXFER_ATTR_MODIFYTIME 0x00000020 SSH_FILEXFER_ATTR_MODIFYTIME 0x00000020
SSH_FILEXFER_ATTR_ACL 0x00000040 SSH_FILEXFER_ATTR_ACL 0x00000040
SSH_FILEXFER_ATTR_OWNERGROUP 0x00000080 SSH_FILEXFER_ATTR_OWNERGROUP 0x00000080
SSH_FILEXFER_ATTR_SUBSECOND_TIMES 0x00000100 SSH_FILEXFER_ATTR_SUBSECOND_TIMES 0x00000100
SSH_FILEXFER_ATTR_BITS 0x00000200 SSH_FILEXFER_ATTR_BITS 0x00000200
SSH_FILEXFER_ATTR_ALLOCATION_SIZE 0x00000400 SSH_FILEXFER_ATTR_ALLOCATION_SIZE 0x00000400
SSH_FILEXFER_ATTR_TEXT_HINT 0x00000800 SSH_FILEXFER_ATTR_TEXT_HINT 0x00000800
SSH_FILEXFER_ATTR_MIME_TYPE 0x00001000 SSH_FILEXFER_ATTR_MIME_TYPE 0x00001000
SSH_FILEXFER_ATTR_LINK_COUNT 0x00002000 SSH_FILEXFER_ATTR_LINK_COUNT 0x00002000
SSH_FILEXFER_ATTR_UNTRANSLATED_NAME 0x00004000 SSH_FILEXFER_ATTR_UNTRANSLATED_NAME 0x00004000
SSH_FILEXFER_ATTR_CTIME 0x00008000
SSH_FILEXFER_ATTR_EXTENDED 0x80000000 SSH_FILEXFER_ATTR_EXTENDED 0x80000000
0x00000002 was used in a previous version of this protocol. It is 0x00000002 was used in a previous version of this protocol. It is
now a reserved value and MUST NOT appear in the mask. Some future now a reserved value and MUST NOT appear in the mask. Some future
version of this protocol may reuse this value. version of this protocol may reuse this value.
6.2 Type 6.2 Type
The type field is always present. The following types are defined: The type field is always present. The following types are defined:
skipping to change at page 16, line 13 skipping to change at page 18, line 13
extended or truncated to the specified size. extended or truncated to the specified size.
Files opened with the SSH_FXF_ACCESS_TEXT flag may have a size that Files opened with the SSH_FXF_ACCESS_TEXT flag may have a size that
is greater or less than the value of the size field. The server MAY is greater or less than the value of the size field. The server MAY
fail setstat operations specifying size for files opened with the fail setstat operations specifying size for files opened with the
SSH_FXF_ACCESS_TEXT flag. SSH_FXF_ACCESS_TEXT flag.
6.4 allocation-size 6.4 allocation-size
The 'allocation-size' field specifies the number of bytes that the The 'allocation-size' field specifies the number of bytes that the
file consumes on disk. This is greater than or equal to the 'size' file consumes on disk. This field MAY be less than the 'size' field
field. if the file is 'sparse' (Section 6.9).
When present during file creation, the file SHOULD be created and the When present during file creation, the file SHOULD be created and the
specified number of bytes pre-allocated. If the pre-allocation specified number of bytes pre-allocated. If the pre-allocation
fails, the file should be removed and an error returned. fails, the file should be removed (if it was created) and an error
returned.
If this field is present during a setstat operation, the file SHOULD If this field is present during a setstat operation, the file SHOULD
be extended or truncated to the specified size. The 'size' of the be extended or truncated to the specified size. The 'size' of the
file may be affected by this operation. If the operation succeeds, file may be affected by this operation. If the operation succeeds,
it should be the min of the 'size' before the operation and the new the 'size' should be the minimum of the 'size' before the operation
'allocation-size'. and the new 'allocation-size'.
Querying the 'allocation-size' after setting it MUST return a value Querying the 'allocation-size' after setting it MUST return a value
that is greater-than or equal to the value set, but it MAY not return that is greater-than or equal to the value set, but it MAY not return
the precise value set. the precise value set.
If both 'size' and 'allocation-size' are set during a setstat
operation, and 'allocation-size' is less than 'size', the server MUST
return SSH_FX_INVALID_PARAMETER.
6.5 Owner and Group 6.5 Owner and Group
The 'owner' and 'group' fields are represented as UTF-8 strings; this The 'owner' and 'group' fields are represented as UTF-8 strings; this
is the form used by NFS v4. See NFS version 4 Protocol [RFC3010]. is the form used by NFS v4. See NFS version 4 Protocol [RFC3010].
The following text is selected quotations from section 5.6. The following text is selected quotations from section 5.6.
To avoid a representation that is tied to a particular underlying To avoid a representation that is tied to a particular underlying
implementation at the client or server, the use of UTF-8 strings has implementation at the client or server, the use of UTF-8 strings has
been chosen. The string should be of the form user@dns_domain". been chosen. The string should be of the form "user@dns_domain".
This will allow for a client and server that do not use the same This will allow for a client and server that do not use the same
local representation the ability to translate to a common syntax that local representation the ability to translate to a common syntax that
can be interpreted by both. In the case where there is no can be interpreted by both. In the case where there is no
translation available to the client or server, the attribute value translation available to the client or server, the attribute value
must be constructed without the "@". Therefore, the absence of the @ must be constructed without the "@". Therefore, the absence of the @
from the owner or owner_group attribute signifies that no translation from the owner or owner_group attribute signifies that no translation
was available and the receiver of the attribute should not place any was available and the receiver of the attribute should not place any
special meaning with the attribute value. Even though the attribute special meaning on the attribute value. Even though the attribute
value cannot be translated, it may still be useful. In the case of a value cannot be translated, it may still be useful. In the case of a
client, the attribute string may be used for local display of client, the attribute string may be used for local display of
ownership. ownership.
user@localhost represents a user in the context of the server. user@localhost represents a user in the context of the server.
If either the owner or group field is zero length, the field should If either the owner or group field is zero length, the field should
be considered absent, and no change should be made to that specific be considered absent, and no change should be made to that specific
field. field during a modification operation.
6.6 Permissions 6.6 Permissions
The 'permissions' field contains a bit mask specifying file The 'permissions' field contains a bit mask specifying file
permissions. These permissions correspond to the st_mode field of permissions. These permissions correspond to the st_mode field of
the stat structure defined by POSIX [IEEE.1003-1.1996]. the stat structure defined by POSIX [IEEE.1003-1.1996].
This protocol uses the following values for the symbols declared in This protocol uses the following values for the symbols declared in
the posix standard. the POSIX standard.
S_IRUSR 0000400 (octal) S_IRUSR 0000400 (octal)
S_IWUSR 0000200 S_IWUSR 0000200
S_IXUSR 0000100 S_IXUSR 0000100
S_IRGRP 0000040 S_IRGRP 0000040
S_IWGRP 0000020 S_IWGRP 0000020
S_IXGRP 0000010 S_IXGRP 0000010
S_IROTH 0000004 S_IROTH 0000004
S_IWOTH 0000002 S_IWOTH 0000002
S_IXOTH 0000001 S_IXOTH 0000001
skipping to change at page 17, line 39 skipping to change at page 19, line 43
S_ISVTX 0001000 S_ISVTX 0001000
Implementations MUST NOT send bits that are not defined. Implementations MUST NOT send bits that are not defined.
The server SHOULD NOT apply a 'umask' to the mode bits; but should The server SHOULD NOT apply a 'umask' to the mode bits; but should
set the mode bits as specified by the client. The client MUST apply set the mode bits as specified by the client. The client MUST apply
an appropriate 'umask' to the mode bits before sending them. an appropriate 'umask' to the mode bits before sending them.
6.7 Times 6.7 Times
The 'atime', 'createtime', and 'mtime' contain the access, creation, The 'atime' field contains the last access time of the file. Many
and modification times of the files, respectively. They are operating systems either don't have this field, only optionally
represented as seconds from Jan 1, 1970 in UTC. maintain it, or maintain it with less resolution than other fields.
A negative value indicates number of seconds before Jan 1, 1970. In The 'mtime' contains the last time the file was written.
'createtime' contains the creation time of the file.
'ctime' contains the last time the file attrbutes were changed. The
exact meaning of this field depends on the server.
All times are represented as seconds from Jan 1, 1970 in UTC. A
negative value indicates number of seconds before Jan 1, 1970. In
both cases, if the SSH_FILEXFER_ATTR_SUBSECOND_TIMES flag is set, the both cases, if the SSH_FILEXFER_ATTR_SUBSECOND_TIMES flag is set, the
nseconds field is to be added to the seconds field for the final time nseconds field is to be added to the seconds field for the final time
representation. For example, if the time to be represented is representation. For example, if the time to be represented is one-
one-half second before 0 hour January 1, 1970, the seconds field half second before 0 hour January 1, 1970, the seconds field would
would have a value of negative one (-1) and the nseconds fields would have a value of negative one (-1) and the nseconds fields would have
have a value of one-half second (500000000). Values greater than a value of one-half second (500000000). Values greater than
999,999,999 for nseconds are considered invalid. 999,999,999 for nseconds are considered invalid.
6.8 ACL 6.8 ACL
The 'ACL' field contains an ACL similar to that defined in section The 'ACL' field contains an ACL similar to that defined in section
5.9 of NFS version 4 Protocol [RFC3010]. 5.9 of NFS version 4 Protocol [RFC3010].
uint32 ace-count uint32 ace-count
repeated ace-count time: repeated ace-count time:
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Version 4 Protocol [RFC3010] section 5.9.2: Version 4 Protocol [RFC3010] section 5.9.2:
ACE4_FILE_INHERIT_ACE 0x00000001 ACE4_FILE_INHERIT_ACE 0x00000001
ACE4_DIRECTORY_INHERIT_ACE 0x00000002 ACE4_DIRECTORY_INHERIT_ACE 0x00000002
ACE4_NO_PROPAGATE_INHERIT_ACE 0x00000004 ACE4_NO_PROPAGATE_INHERIT_ACE 0x00000004
ACE4_INHERIT_ONLY_ACE 0x00000008 ACE4_INHERIT_ONLY_ACE 0x00000008
ACE4_SUCCESSFUL_ACCESS_ACE_FLAG 0x00000010 ACE4_SUCCESSFUL_ACCESS_ACE_FLAG 0x00000010
ACE4_FAILED_ACCESS_ACE_FLAG 0x00000020 ACE4_FAILED_ACCESS_ACE_FLAG 0x00000020
ACE4_IDENTIFIER_GROUP 0x00000040 ACE4_IDENTIFIER_GROUP 0x00000040
ace-mask is any combination of the following flags (taken from NFS ace-mask is any combination of the following flags (taken from
Version 4 Protocol [RFC3010] section 5.9.3: [RFC3010], section 5.9.3. The semantic meaning of these flags is
also given in [RFC3010].
ACE4_READ_DATA 0x00000001 ACE4_READ_DATA 0x00000001
ACE4_LIST_DIRECTORY 0x00000001 ACE4_LIST_DIRECTORY 0x00000001
ACE4_WRITE_DATA 0x00000002 ACE4_WRITE_DATA 0x00000002
ACE4_ADD_FILE 0x00000002 ACE4_ADD_FILE 0x00000002
ACE4_APPEND_DATA 0x00000004 ACE4_APPEND_DATA 0x00000004
ACE4_ADD_SUBDIRECTORY 0x00000004 ACE4_ADD_SUBDIRECTORY 0x00000004
ACE4_READ_NAMED_ATTRS 0x00000008 ACE4_READ_NAMED_ATTRS 0x00000008
ACE4_WRITE_NAMED_ATTRS 0x00000010 ACE4_WRITE_NAMED_ATTRS 0x00000010
ACE4_EXECUTE 0x00000020 ACE4_EXECUTE 0x00000020
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NETWORK Accessed via the network. NETWORK Accessed via the network.
DIALUP Accessed as a dialup user to the server. DIALUP Accessed as a dialup user to the server.
BATCH Accessed from a batch job. BATCH Accessed from a batch job.
ANONYMOUS Accessed without any authentication. ANONYMOUS Accessed without any authentication.
AUTHENTICATED Any authenticated user (opposite of ANONYMOUS). AUTHENTICATED Any authenticated user (opposite of ANONYMOUS).
SERVICE Access from a system service. SERVICE Access from a system service.
To avoid conflict, these special identifiers are distinguish by an To avoid conflict, these special identifiers are distinguish by an
appended "@". For example: ANONYMOUS@. appended "@". For example: ANONYMOUS@.
6.9 attrib-bits 6.9 attrib-bits and attrib-bits-valid
These bits reflect various attributes of the file or directory on the These fields, taken together, reflect various attributes of the file
server. or directory, on the server.
Bits not set in 'attrib-bits-valid' MUST be ignored in the 'attrib-
bits' field. This allows both the server and the client to
comminicute only the bits it knows about without inadvertantly
twiddling bits they don't understand.
The following attrib-bits are defined: The following attrib-bits are defined:
SSH_FILEXFER_ATTR_FLAGS_READONLY 0x00000001 SSH_FILEXFER_ATTR_FLAGS_READONLY 0x00000001
SSH_FILEXFER_ATTR_FLAGS_SYSTEM 0x00000002 SSH_FILEXFER_ATTR_FLAGS_SYSTEM 0x00000002
SSH_FILEXFER_ATTR_FLAGS_HIDDEN 0x00000004 SSH_FILEXFER_ATTR_FLAGS_HIDDEN 0x00000004
SSH_FILEXFER_ATTR_FLAGS_CASE_INSENSITIVE 0x00000008 SSH_FILEXFER_ATTR_FLAGS_CASE_INSENSITIVE 0x00000008
SSH_FILEXFER_ATTR_FLAGS_ARCHIVE 0x00000010 SSH_FILEXFER_ATTR_FLAGS_ARCHIVE 0x00000010
SSH_FILEXFER_ATTR_FLAGS_ENCRYPTED 0x00000020 SSH_FILEXFER_ATTR_FLAGS_ENCRYPTED 0x00000020
SSH_FILEXFER_ATTR_FLAGS_COMPRESSED 0x00000040 SSH_FILEXFER_ATTR_FLAGS_COMPRESSED 0x00000040
skipping to change at page 20, line 24 skipping to change at page 22, line 28
SSH_FILEXFER_ATTR_FLAGS_IMMUTABLE 0x00000200 SSH_FILEXFER_ATTR_FLAGS_IMMUTABLE 0x00000200
SSH_FILEXFER_ATTR_FLAGS_SYNC 0x00000400 SSH_FILEXFER_ATTR_FLAGS_SYNC 0x00000400
SSH_FILEXFER_ATTR_FLAGS_TRANSLATION_ERR 0x00000800 SSH_FILEXFER_ATTR_FLAGS_TRANSLATION_ERR 0x00000800
SSH_FILEXFER_ATTR_FLAGS_READONLY SSH_FILEXFER_ATTR_FLAGS_READONLY
Advisory, read-only bit. This bit is not part of the access Advisory, read-only bit. This bit is not part of the access
control information on the file, but is rather an advisory field control information on the file, but is rather an advisory field
indicating that the file should not be written. indicating that the file should not be written.
SSH_FILEXFER_ATTR_FLAGS_SYSTEM SSH_FILEXFER_ATTR_FLAGS_SYSTEM
The file is part of operating system. The file is part of the operating system.
SSH_FILEXFER_ATTR_FLAGS_HIDDEN SSH_FILEXFER_ATTR_FLAGS_HIDDEN
File SHOULD NOT be shown to user unless specifically requested. File SHOULD NOT be shown to user unless specifically requested.
For example, most UNIX systems SHOULD set this bit if the filename For example, most UNIX systems SHOULD set this bit if the filename
begins with a 'period'. This bit may be read-only (Section 4.4). begins with a 'period'. This bit may be read-only (Section 4.5).
Most UNIX systems will not allow this to be changed. Most UNIX systems will not allow this to be changed.
SSH_FILEXFER_ATTR_FLAGS_CASE_INSENSITIVE SSH_FILEXFER_ATTR_FLAGS_CASE_INSENSITIVE
This attribute can only apply to directories. This attribute is This attribute applies only to directories. This attribute is
always read-only, and cannot be modified. This attribute means always read-only, and cannot be modified. This attribute means
that files and directory names in this directory should be that files and directory names in this directory should be
compared without regard to case. compared without regard to case.
It is recommended that where possible, the server's filesystem be It is recommended that where possible, the server's filesystem be
allowed to do comparisons. For example, if a client wished to allowed to do comparisons. For example, if a client wished to
prompt a user before overwriting a file, it should not compare the prompt a user before overwriting a file, it should not compare the
new name with the previously retrieved list of names in the new name with the previously retrieved list of names in the
directory. Rather, it should first try to create the new file by directory. Rather, it should first try to create the new file by
specifying SSH_FXF_CREATE_NEW flag. Then, if this fails and specifying SSH_FXF_CREATE_NEW flag. Then, if this fails and
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The file is stored on disk using file-system level transparent The file is stored on disk using file-system level transparent
compression. This flag does not affect the file data on the wire. compression. This flag does not affect the file data on the wire.
SSH_FILEXFER_ATTR_FLAGS_SPARSE SSH_FILEXFER_ATTR_FLAGS_SPARSE
The file is a sparse file; this means that file blocks that have The file is a sparse file; this means that file blocks that have
not been explicitly written are not stored on disk. For example, not been explicitly written are not stored on disk. For example,
if a client writes a buffer at 10 M from the beginning of the if a client writes a buffer at 10 M from the beginning of the
file, the blocks between the previous EOF marker and the 10 M file, the blocks between the previous EOF marker and the 10 M
offset would not consume physical disk space. offset would not consume physical disk space.
Some server may store all files as sparse files, in which case Some servers may store all files as sparse files, in which case
this bit will be unconditionally set. Other servers may not have this bit will be unconditionally set. Other servers may not have
a mechanism for determining if the file is sparse, and so the file a mechanism for determining if the file is sparse, and so the file
MAY be stored sparse even if this flag is not set. MAY be stored sparse even if this flag is not set.
SSH_FILEXFER_ATTR_FLAGS_APPEND_ONLY SSH_FILEXFER_ATTR_FLAGS_APPEND_ONLY
The file can only be opened for writing in append mode. Opening the file without either the SSH_FXF_ACCESS_APPEND_DATA or
the SSH_FXF_ACCESS_APPEND_DATA_ATOMIC flag (Section 7.1.1.3) MUST
result in an SSH_FX_INVALID_PARAMETER error.
SSH_FILEXFER_ATTR_FLAGS_IMMUTABLE SSH_FILEXFER_ATTR_FLAGS_IMMUTABLE
The file cannot be deleted or renamed, no hard link can be created The file cannot be deleted or renamed, no hard link can be created
to this file and no data can be written to the file. to this file, and no data can be written to the file.
This bit implies a stronger level of protection than This bit implies a stronger level of protection than
SSH_FILEXFER_ATTR_FLAGS_READONLY, the file permission mask or SSH_FILEXFER_ATTR_FLAGS_READONLY, the file permission mask or
ACLs. Typically even the superuser cannot write to immutable ACLs. Typically even the superuser cannot write to immutable
files, and only the superuser can set or remove the bit. files, and only the superuser can set or remove the bit.
SSH_FILEXFER_ATTR_FLAGS_SYNC SSH_FILEXFER_ATTR_FLAGS_SYNC
When the file is modified, the changes are written synchronously When the file is modified, the changes are written synchronously
to the disk. to the disk.
SSH_FILEXFER_ATTR_FLAGS_TRANSLATION_ERR SSH_FILEXFER_ATTR_FLAGS_TRANSLATION_ERR
The server MAY include this bit in a directory listing or realpath The server MAY include this bit in a directory listing or realpath
response. It indicates there was a failure in the translation to response. It indicates there was a failure in the translation to
UTF-8. If this flag is included, the server SHOULD also include UTF-8. If this flag is included, the server SHOULD also include
the UNTRANSLATED_NAME attribute. the UNTRANSLATED_NAME attribute.
6.10 Text Hint 6.10 text-hint
The value is one of the following enumerations, and indicates what The value is one of the following enumerations, and indicates what
the server knows about the content of the file. the server knows about the content of the file.
SSH_FILEXFER_ATTR_KNOWN_TEXT 0x00 SSH_FILEXFER_ATTR_KNOWN_TEXT 0x00
SSH_FILEXFER_ATTR_GUESSED_TEXT 0x01 SSH_FILEXFER_ATTR_GUESSED_TEXT 0x01
SSH_FILEXFER_ATTR_KNOWN_BINARY 0x02 SSH_FILEXFER_ATTR_KNOWN_BINARY 0x02
SSH_FILEXFER_ATTR_GUESSED_BINARY 0x03 SSH_FILEXFER_ATTR_GUESSED_BINARY 0x03
SSH_FILEXFER_ATTR_KNOWN_TEXT SSH_FILEXFER_ATTR_KNOWN_TEXT
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flag. flag.
SSH_FILEXFER_ATTR_KNOWN_BINARY SSH_FILEXFER_ATTR_KNOWN_BINARY
The server knows the file has binary content. The server knows the file has binary content.
SSH_FILEXFER_ATTR_GUESSED_BINARY SSH_FILEXFER_ATTR_GUESSED_BINARY
The server has applied a hueristic or other mechanism and believes The server has applied a hueristic or other mechanism and believes
has binary content, and should not be opened with the has binary content, and should not be opened with the
SSH_FXF_ACCESS_TEXT_MODE flag. SSH_FXF_ACCESS_TEXT_MODE flag.
This flag MUST NOT be present during a setstat operation. If this This flag MUST NOT be present during either a setstat or a fsetstat
flag is present during an fsetstat operation, the file handle is operation.
converted to a text-mode handle, as if it had been opened with
SSH_FXF_ACCESS_TEXT_MODE.
6.11 Mime type 6.11 mime-type
The 'mime-type' field contains the mime-type [RFC1521] string. Most The 'mime-type' field contains the mime-type [RFC1521] string. Most
servers will not know this information and should not set the bit in servers will not know this information and should not set the bit in
their supported-attribute-mask. their supported-attribute-mask.
6.12 Link Count 6.12 link-count
The 'link-count' field contains the hard link count of the file. This field contains the hard link count of the file. This attribute
This attribute MUST NOT be present during a setstat operation. MUST NOT be present during a setstat operation.
6.13 Extended Attributes 6.13 untranslated-name
This field contains the name before filename translation was attempt.
It MUST NOT be included unless the server also set the
SSH_FILEXFER_ATTR_FLAGS_TRANSLATION_ERR (Section 6.9) bit in the
attrib-bits field.
6.14 Extended Attributes
The SSH_FILEXFER_ATTR_EXTENDED flag provides a general extension The SSH_FILEXFER_ATTR_EXTENDED flag provides a general extension
mechanism for the attrib structure. If the flag is specified, then mechanism for the attrib structure. If the flag is specified, then
the 'extended_count' field is present. It specifies the number of the 'extended_count' field is present. It specifies the number of
extended_type-extended_data pairs that follow. Each of these pairs 'extension-pair' items that follow. Each of these items specifies an
specifies an extended attribute. For each of the attributes, the extended attribute. Implementations MUST return SSH_FX_UNSUPPORTED
extended_type field should be a string of the format "name@domain", if there are any unrecognized extensions. Clients can avoid sending
where "domain" is a valid, registered domain name and "name" unsupported extensions by examining the attrib-extension-names of the
identifies the method. The IETF may later standardize certain names "supported2" extension attrib-extension-names (Section 4.5).
that deviate from this format (e.g., that do not contain the "@"
sign). The interpretation of 'extended_data' depends on the type.
Implementations SHOULD ignore extended data fields that they do not
understand.
Additional fields can be added to the attributes by either defining Additional fields can be added to the attributes by either defining
additional bits to the flags field to indicate their presence, or by additional bits to the flags field to indicate their presence, or by
defining extended attributes for them. The extended attributes defining extended attributes for them. The extended attributes
mechanism is recommended for most purposes; additional flags bits mechanism is recommended for most purposes; additional flags bits
should only be defined by an IETF standards action that also should only be defined by an IETF standards action that also
increments the protocol version number. The use of such new fields increments the protocol version number. The use of such new fields
MUST be negotiated by the version number in the protocol exchange. MUST be negotiated by the version number in the protocol exchange.
It is a protocol error if a packet with unsupported protocol bits is It is a protocol error if a packet with unsupported protocol bits is
received. received.
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7.1.1.1 filename 7.1.1.1 filename
The 'filename' field specifies the file name. See Section ''File The 'filename' field specifies the file name. See Section ''File
Names'' for more information. If 'filename' is a directory file, the Names'' for more information. If 'filename' is a directory file, the
server MUST return an SSH_FX_FILE_IS_A_DIRECTORY error. server MUST return an SSH_FX_FILE_IS_A_DIRECTORY error.
7.1.1.2 desired-access 7.1.1.2 desired-access
The 'desired-access' field is a bitmask containing a combination of The 'desired-access' field is a bitmask containing a combination of
values from the ace-mask flags from section 5.7. values from the ace-mask flags (Section 6.8). Note that again, the
meaning of these flags is given in [RFC3010].
The server MUST be prepared to translate the SFTP access flags into The server MUST be prepared to translate the SFTP access flags into
it's local equivilants. If the server can not grant the access its local equivalents. If the server cannot grant the access
desired, it MUST return SSH_FX_PERMISSION_DENIED. desired, it MUST return SSH_FX_PERMISSION_DENIED.
The server MAY open the file with greater access than requested if The server MAY open the file with greater access than requested if
the user has such access and the server implementation requires it. the user has such access and the server implementation requires it.
For example, a server that does not distinguish between For example, a server that does not distinguish between
READ_ATTRIBUTE and READ_DATA will have to request full 'read' access READ_ATTRIBUTE and READ_DATA will have to request full 'read' access
to the file when the client only requested READ_ATTRIBUTE, resulting to the file when the client only requested READ_ATTRIBUTE, resulting
in greater access than the client originaly requested. in greater access than the client originaly requested.
In such cases, it is possible, and permissable in the protocol, that In such cases, it is possible, and permissable in the protocol, that
the client could open a file requesting some limitted access, and the client could open a file requesting some limited access, and then
then access the file in a way not permitted by that limitted access access the file in a way not permitted by that limited access and the
and the server would permit such action. However, the server MUST server would permit such action. However, the server MUST NOT ever
NOT ever grant access to the file that the client does not actually grant access to the file that the client does not actually have the
have the rights to. rights to.
7.1.1.3 flags 7.1.1.3 flags
The 'flags' field controls various aspects of the operation, The 'flags' field controls various aspects of the operation,
including whether or not the file is created and the kind of locking including whether or not the file is created and the kind of locking
desired. desired.
The following 'flags' are defined: The following 'flags' are defined:
SSH_FXF_ACCESS_DISPOSITION = 0x00000007 SSH_FXF_ACCESS_DISPOSITION = 0x00000007
SSH_FXF_CREATE_NEW = 0x00000000 SSH_FXF_CREATE_NEW = 0x00000000
SSH_FXF_CREATE_TRUNCATE = 0x00000001 SSH_FXF_CREATE_TRUNCATE = 0x00000001
SSH_FXF_OPEN_EXISTING = 0x00000002 SSH_FXF_OPEN_EXISTING = 0x00000002
SSH_FXF_OPEN_OR_CREATE = 0x00000003 SSH_FXF_OPEN_OR_CREATE = 0x00000003
SSH_FXF_TRUNCATE_EXISTING = 0x00000004 SSH_FXF_TRUNCATE_EXISTING = 0x00000004
SSH_FXF_ACCESS_APPEND_DATA = 0x00000008 SSH_FXF_ACCESS_APPEND_DATA = 0x00000008
SSH_FXF_ACCESS_APPEND_DATA_ATOMIC = 0x00000010 SSH_FXF_ACCESS_APPEND_DATA_ATOMIC = 0x00000010
SSH_FXF_ACCESS_TEXT_MODE = 0x00000020 SSH_FXF_ACCESS_TEXT_MODE = 0x00000020
SSH_FXF_ACCESS_READ_LOCK = 0x00000040 SSH_FXF_ACCESS_BLOCK_READ = 0x00000040
SSH_FXF_ACCESS_WRITE_LOCK = 0x00000080 SSH_FXF_ACCESS_BLOCK_WRITE = 0x00000080
SSH_FXF_ACCESS_DELETE_LOCK = 0x00000100 SSH_FXF_ACCESS_BLOCK_DELETE = 0x00000100
SSH_FXF_ACCESS_NOFOLLOW = 0x00000200 SSH_FXF_ACCESS_BLOCK_ADVISORY = 0x00000200
SSH_FXF_ACCESS_DELETE_ON_CLOSE = 0x00000400 SSH_FXF_ACCESS_NOFOLLOW = 0x00000400
SSH_FXF_ACCESS_DELETE_ON_CLOSE = 0x00000800
SSH_FXF_ACCESS_DISPOSITION SSH_FXF_ACCESS_DISPOSITION
Disposition is a 3 bit field that controls how the file is opened. Disposition is a 3 bit field that controls how the file is opened.
The server MUST support these bits. Any one of the following The server MUST support these bits. Any one of the following
enumeration is allowed: enumeration is allowed:
SSH_FXF_CREATE_NEW SSH_FXF_CREATE_NEW
A new file is created; if the file already exists, the server A new file is created; if the file already exists, the server
MUST return status SSH_FX_FILE_ALREADY_EXISTS. MUST return status SSH_FX_FILE_ALREADY_EXISTS.
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If both append flags are specified, the server SHOULD use atomic If both append flags are specified, the server SHOULD use atomic
append if it is available, but SHOULD use non-atomic appends append if it is available, but SHOULD use non-atomic appends
otherwise. The server SHOULD NOT fail the request in this case. otherwise. The server SHOULD NOT fail the request in this case.
SSH_FXF_TEXT SSH_FXF_TEXT
Indicates that the server should treat the file as text and Indicates that the server should treat the file as text and
convert it to the canonical newline convention in use. (See convert it to the canonical newline convention in use. (See
Determining Server Newline Convention. (Section 4.3) Determining Server Newline Convention. (Section 4.3)
When a file is opened with the FXF_TEXT flag, the offset field in When a file is opened with the FXF_TEXT flag, the offset field in
both the read and write function are ignored. the read and write functions is ignored.
Servers MUST correctly process multiple, parallel reads and writes Servers MUST process multiple, parallel reads and writes correctly
correctly in this mode. Naturally, it is permissible for them to in this mode. Naturally, it is permissible for them to do this by
do this by serializing the requests. serializing the requests.
Clients SHOULD use the SSH_FXF_ACCESS_APPEND_DATA flag to append Clients SHOULD use the SSH_FXF_ACCESS_APPEND_DATA flag to append
data to a text file rather then using write with a calculated data to a text file rather then using write with a calculated
offset. offset.
To support seeks on text files the following SSH_FXP_EXTENDED To support seeks on text files the following SSH_FXP_EXTENDED
packet is defined. packet is defined.
string "text-seek" string "text-seek"
string file-handle string file-handle
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SSH_FX_EOF status. SSH_FX_EOF status.
Servers SHOULD support at least one "text-seek" in order to Servers SHOULD support at least one "text-seek" in order to
support resume. However, a client MUST be prepared to receive support resume. However, a client MUST be prepared to receive
SSH_FX_OP_UNSUPPORTED when attempting a "text-seek" operation. SSH_FX_OP_UNSUPPORTED when attempting a "text-seek" operation.
The client can then try a fall-back strategy, if it has one. The client can then try a fall-back strategy, if it has one.
Clients MUST be prepared to handle SSH_FX_OP_UNSUPPORTED returned Clients MUST be prepared to handle SSH_FX_OP_UNSUPPORTED returned
for read or write operations that are not sequential. for read or write operations that are not sequential.
SSH_FXF_ACCESS_READ_LOCK SSH_FXF_ACCESS_BLOCK_READ
The file should be opened with a read lock. The server MUST The server MUST guarantee that no other open has taken place which
gaurantee that the client will be the exclusive reader of the file blocked handle has been opened with ACE4_READ_DATA access, and
until the client closes the handle. If there is a conflicting that no other handle will be opened with ACE4_READ_DATA access
lock the server MUST return SSH_FX_LOCK_CONFlICT. If the server until the client closes the handle. (This MUST apply both to
cannot make the locking gaurantee, it MUST return other clients and to other processes on the server.)
SSH_FX_OP_UNSUPPORTED.
SSH_FXF_ACCESS_WRITE_LOCK If there is a conflicting lock the server MUST return
The file should be opened with a write lock. The server MUST SSH_FX_LOCK_CONFLICT. If the server cannot make the locking
gaurantee that the client will be the exclusive writer of the file guarantee, it MUST return SSH_FX_OP_UNSUPPORTED.
until the client closes the handle.
SSH_FXF_ACCESS_DELETE_LOCK Other handles MAY be opened for ACE4_WRITE_DATA or any other
The file should be opened with a delete lock. The server MUST combinatation of accesses, as long as ACE4_READ_DATA is not
gaurantee that the file will not be deleted until the client included in the mask.
closes the handle.
SSH_FXF_ACCESS_BLOCK_WRITE
The server MUST guarantee that no other lock has been opened with
ACE4_WRITE_DATA or ACE4_APPEND_DATA access, and that no other
handle will be opened with ACE4_WRITE_DATA or ACE4_APPEND_DATA
access until the client closes the handle. (This MUST apply both
to other clients and to other processes on the server.)
If there is a conflicting lock the server MUST return
SSH_FX_LOCK_CONFLICT. If the server cannot make the locking
guarantee, it MUST return SSH_FX_OP_UNSUPPORTED.
Other handles MAY be opened for ACE4_READ_DATA or any other
combinatation of accesses, as long as neither ACE4_WRITE_DATA nor
ACE4_APPEND_DATA are included in the mask.
SSH_FXF_ACCESS_BLOCK_DELETE
The server MUST guarantee that no other handle has been opened
with ACE4_DELETE access, opened with the
SSH_FXF_ACCESS_DELETE_ON_CLOSE flag set, and that no other handle
will be opened with ACE4_DELETE access or with the
SSH_FXF_ACCESS_DELETE_ON_CLOSE flag set, and that the file itself
is not deleted in any other way until the client closes the
handle.
If there is a conflicting lock the server MUST return
SSH_FX_LOCK_CONFLICT. If the server cannot make the locking
guarantee, it MUST return SSH_FX_OP_UNSUPPORTED.
SSH_FXF_ACCESS_BLOCK_ADVISORY
If this bit is set, the above BLOCK modes are advisory. In
advisory mode, only other accesses that specify a BLOCK mode need
be considered when determining whether the BLOCK can be granted,
and the server need not prevent I/O operations that violate the
block mode.
The server MAY perform mandatory locking even if the
BLOCK_ADVISORY bit is set.
SSH_FXF_ACCESS_NOFOLLOW SSH_FXF_ACCESS_NOFOLLOW
If the final component of the path is a symlink, then the open If the final component of the path is a symlink, then the open
MUST fail, and the error SSH_FX_LINK_LOOP MUST be returned. MUST fail, and the error SSH_FX_LINK_LOOP MUST be returned.
SSH_FXF_ACCESS_DELETE_ON_CLOSE SSH_FXF_ACCESS_DELETE_ON_CLOSE
The file should be deleted when the last handle to it is closed. The file should be deleted when the last handle to it is closed.
(The last handle may not be an sftp-handle.) This MAY be emulated (The last handle may not be an sftp-handle.) This MAY be emulated
by a server if the OS doesn't support it by deleting the file when by a server if the OS doesn't support it by deleting the file when
this handle is closed. this handle is closed.
The 'attrs' field specifies the initial attributes for the file. The 'attrs' field specifies the initial attributes for the file.
Default values MUST be supplied by the server for those attributes Default values MUST be supplied by the server for those attributes
that are not specified. See Section ''File Attributes'' for more that are not specified. See Section ''File Attributes'' for more
information. information.
The 'attrs' field is ignored if an exiting file is opened. The 'attrs' field is ignored if an existing file is opened.
The following table is provided to assist in mapping posix semantics The following table is provided to assist in mapping POSIX semantics
to equivalent SFTP file open parameters: to equivalent SFTP file open parameters:
O_RDONLY O_RDONLY
desired-access = READ_DATA|READ_ATTRIBUTES desired-access = READ_DATA|READ_ATTRIBUTES
O_WRONLY O_WRONLY
desired-access = WRITE_DATA|WRITE_ATTRIBUTES desired-access = WRITE_DATA|WRITE_ATTRIBUTES
O_RDWR O_RDWR
desired-access = desired-access = READ_DATA|READ_ATTRIBUTES|WRITE_DATA|
READ_DATA|READ_ATTRIBUTES|WRITE_DATA|WRITE_ATTRIBUTES WRITE_ATTRIBUTES
O_APPEND O_APPEND
desired-access = WRITE_DATA|WRITE_ATTRIBUTES|APPEND_DATA desired-access = WRITE_DATA|WRITE_ATTRIBUTES|APPEND_DATA
flags = SSH_FXF_ACCESS_APPEND_DATA and or flags = SSH_FXF_ACCESS_APPEND_DATA and or
SSH_FXF_ACCESS_APPEND_DATA_ATOMIC SSH_FXF_ACCESS_APPEND_DATA_ATOMIC
O_CREAT O_CREAT
flags = SSH_FXF_OPEN_OR_CREATE flags = SSH_FXF_OPEN_OR_CREATE
O_TRUNC O_TRUNC
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handle handle
'handle' is a handle previously returned in the response to 'handle' is a handle previously returned in the response to
SSH_FXP_OPEN or SSH_FXP_OPENDIR. The handle becomes invalid SSH_FXP_OPEN or SSH_FXP_OPENDIR. The handle becomes invalid
immediately after this request has been sent. immediately after this request has been sent.
The response to this request will be a SSH_FXP_STATUS message. Note The response to this request will be a SSH_FXP_STATUS message. Note
that on some server platforms even a close can fail. For example, if that on some server platforms even a close can fail. For example, if
the server operating system caches writes, and an error occurs while the server operating system caches writes, and an error occurs while
flushing cached writes, the close operation may fail. flushing cached writes, the close operation may fail.
Note that the handle is invalid regardless of the SSH_FXP_STATUS
result. There is no way for the client to recover a handle that
fails to close. The client MUST release all resources associated
with the handle regardless of the status. The server SHOULD take
whatever steps it can to recover from a close failure and to ensure
that all resources associated with the handle on the server are
correctly released.
7.2 Reading and Writing 7.2 Reading and Writing
7.2.1 Reading Files 7.2.1 Reading Files
The following request can be used to read file data: The following request can be used to read file data:
byte SSH_FXP_READ byte SSH_FXP_READ
uint32 request-id uint32 request-id
string handle string handle
uint64 offset uint64 offset
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SSH_FXF_TEXT was specified during the open. SSH_FXF_TEXT was specified during the open.
length length
'length' is the maximum number of bytes to read. 'length' is the maximum number of bytes to read.
The server MUST not respond with more data than is specified by The server MUST not respond with more data than is specified by
the 'length' parameter. However, the server MAY respond with less the 'length' parameter. However, the server MAY respond with less
data if EOF is reached, an error is encountered, or the servers data if EOF is reached, an error is encountered, or the servers
internal buffers can not handle such a large request. internal buffers can not handle such a large request.
For normal disk files, it is normally guaranteed that this will If the server specified a non-zero 'max-read-size' in it's
read the specified number of bytes, or up to end of file. 'supported2' (Section 4.5) extension, then failure to return
If the server specified 'max-read-size' then failure to return
'length' bytes indicates that EOF or an error occured. 'length' bytes indicates that EOF or an error occured.
7.2.2 Reading Directories 7.2.2 Reading Directories
In order to retrieve a directory listing, the client issues one or In order to retrieve a directory listing, the client issues one or
more SSH_FXP_READDIR requests. In order to obtain a complete more SSH_FXP_READDIR requests. In order to obtain a complete
directory listing, the client MUST issue repeated SSH_FXP_READDIR directory listing, the client MUST issue repeated SSH_FXP_READDIR
requests until the server responds with an SSH_FXP_STATUS message. requests until the server responds with an SSH_FXP_STATUS message.
byte SSH_FXP_READDIR byte SSH_FXP_READDIR
uint32 request-id uint32 request-id
string handle string handle
handle handle
'handle' is a handle returned by SSH_FXP_OPENDIR. If 'handle' is 'handle' is a handle returned by SSH_FXP_OPENDIR. If 'handle' is
an oridinary file handle returned by SSH_FXP_OPEN, the server MUST an ordinary file handle returned by SSH_FXP_OPEN, the server MUST
return SSH_FX_INVALID_HANDLE. return SSH_FX_INVALID_HANDLE.
The server responds to this request with either a SSH_FXP_NAME or a The server responds to this request with either a SSH_FXP_NAME or a
SSH_FXP_STATUS message. One or more names may be returned at a time. SSH_FXP_STATUS message. One or more names may be returned at a time.
Full status information is returned for each name in order to speed Full status information is returned for each name in order to speed
up typical directory listings. up typical directory listings.
If there are no more names available to be read, the server MUST If there are no more names available to be read, the server MUST
respond with a SSH_FXP_STATUS message with error code of SSH_FX_EOF. respond with a SSH_FXP_STATUS message with error code of SSH_FX_EOF.
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'handle' is not a handle returned by SSH_FXP_OPEN, the server MUST 'handle' is not a handle returned by SSH_FXP_OPEN, the server MUST
return SSH_FX_INVALID_HANDLE. return SSH_FX_INVALID_HANDLE.
offset offset
'offset' is the offset (in bytes) relative to the beginning of the 'offset' is the offset (in bytes) relative to the beginning of the
file that the write MUST start at. 'offset' is ignored if file that the write MUST start at. 'offset' is ignored if
SSH_FXF_TEXT was specified during the open. SSH_FXF_TEXT was specified during the open.
The write will extend the file if writing beyond the end of the The write will extend the file if writing beyond the end of the
file. It is legal to write to an offset that extends beyond the file. It is legal to write to an offset that extends beyond the
end of the file; the semantics are to write zeroes from the end of end of the file; the semantics are to write the byte value 0x00
the file to the specified offset and then the data. On most from the end of the file to the specified offset and then the
operating systems, such writes do not allocate disk space but data. On most operating systems, such writes do not allocate disk
instead create a sparse file. space but instead create a sparse file.
data data
The data to write to the file. The data to write to the file.
The server responds to a write request with a SSH_FXP_STATUS message. The server responds to a write request with a SSH_FXP_STATUS message.
7.3 Removing and Renaming Files 7.3 Removing and Renaming Files
The following request can be used to remove a file: The following request can be used to remove a file:
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SSH_FXP_FSTAT differs from the others in that it returns status SSH_FXP_FSTAT differs from the others in that it returns status
information for an open file (identified by the file handle). information for an open file (identified by the file handle).
byte SSH_FXP_FSTAT byte SSH_FXP_FSTAT
uint32 request-id uint32 request-id
string handle string handle
uint32 flags uint32 flags
handle handle
'handle' is an open file handle returned by SSH_FXP_OPEN. If 'handle' is an open file handle from either SSH_FXP_OPEN or
'handle' is not a handle returned by SSH_FXP_OPEN, the server MUST SSH_FXP_OPENDIR.
return SSH_FX_INVALID_HANDLE.
The server responds to this request with SSH_FXP_ATTRS or The server responds to this request with SSH_FXP_ATTRS or
SSH_FXP_STATUS. SSH_FXP_STATUS.
7.6 Setting File Attributes 7.6 Setting File Attributes
File attributes may be modified using the SSH_FXP_SETSTAT and File attributes may be modified using the SSH_FXP_SETSTAT and
SSH_FXP_FSETSTAT requests. SSH_FXP_FSETSTAT requests.
byte SSH_FXP_SETSTAT byte SSH_FXP_SETSTAT
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string handle string handle
ATTRS attrs ATTRS attrs
path path
The file system object (e.g. file or directory) whose attributes The file system object (e.g. file or directory) whose attributes
are to be modified. If this object does not exist, or the user are to be modified. If this object does not exist, or the user
does not have sufficient access to write the attributes, the does not have sufficient access to write the attributes, the
request MUST fail. request MUST fail.
handle handle
'handle' is an open file handle returned by SSH_FXP_OPEN. If 'handle' is an open file handle from either SSH_FXP_OPEN or
'handle' is not a handle returned by SSH_FXP_OPEN, the server MUST SSH_FXP_OPENDIR. If the handle was not opened with sufficient
return SSH_FX_INVALID_HANDLE. If the handle was not opened with access to write the requested attributes, the request MUST fail.
sufficient access to write the requested attributes, the request
MUST fail.
attrs attrs
Specifies the modified attributes to be applied. Attributes are Specifies the modified attributes to be applied. Attributes are
discussed in more detail in Section ''File Attributes''. discussed in more detail in Section ''File Attributes''.
The server will respond with a SSH_FXP_STATUS message. The server will respond with a SSH_FXP_STATUS message.
Because some systems must use separate system calls to set various Because some systems must use separate system calls to set various
attributes, it is possible that a failure response will be returned, attributes, it is possible that a failure response will be returned,
but yet some of the attributes may be have been successfully but yet some of the attributes may be have been successfully
modified. If possible, servers SHOULD avoid this situation; however, modified. If possible, servers SHOULD avoid this situation; however,
client MUST be aware that this is possible. clients MUST be aware that this is possible.
7.7 Dealing with Links 7.7 Dealing with Links
The SSH_FXP_READLINK request reads the target of a symbolic link. The SSH_FXP_READLINK request reads the target of a symbolic link.
byte SSH_FXP_READLINK byte SSH_FXP_READLINK
uint32 request-id uint32 request-id
string path [UTF-8] string path [UTF-8]
where 'request-id' is the request identifier and 'path' specifies the where 'request-id' is the request identifier and 'path' specifies the
path name of the symlink to be read. path name of the symlink to be read.
The server will respond with a SSH_FXP_NAME packet containing only The server will respond with a SSH_FXP_NAME packet containing only
one name and a dummy attributes value. The name in the returned one name and a dummy attributes value. The name in the returned
packet contains the target of the link. If an error occurs, the packet contains the target of the link. If an error occurs, the
server MAY respond with SSH_FXP_STATUS. server MAY respond with SSH_FXP_STATUS.
The SSH_FXP_LINK request creates a symbolic link on the server. The SSH_FXP_LINK request creates a link (either hare or symbolic) on
the server.
byte SSH_FXP_LINK byte SSH_FXP_LINK
uint32 request-id uint32 request-id
string new-link-path [UTF-8] string new-link-path [UTF-8]
string existing-path [UTF-8] string existing-path [UTF-8]
bool sym-link bool sym-link
new-link-path new-link-path
Specifies the path name of the new link to create. Specifies the path name of the new link to create.
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is generally possible to create symbolic links across device is generally possible to create symbolic links across device
boundaries; however, it is not required that a server support boundaries; however, it is not required that a server support
this. this.
If 'sym-link' is false, the link should be a hard link, or a If 'sym-link' is false, the link should be a hard link, or a
second directory entry refering to the same file or directory second directory entry refering to the same file or directory
object. It is generally not possible to create hard links across object. It is generally not possible to create hard links across
devices. devices.
The server shall respond with a SSH_FXP_STATUS. Clients should be The server shall respond with a SSH_FXP_STATUS. Clients should be
aware that some server may return SSH_FX_OP_UNSUPPORTED for either aware that some servers may return SSH_FX_OP_UNSUPPORTED for either
the hard-link, sym-link, or both operations. the hard-link, sym-link, or both operations.
The SSH_FXP_LOCK creates a byte-range lock on the file specified by
the handle. The lock can be either mandatory (meaning that the
server enforces that no other process or client can perform
operations in violation of the lock) or advisory (meaning that no
other process can obtain a conflicting lock, but the server does not
enforce that no operation violates the lock.
A server MAY implement an advisory lock in a mandatory fashion; in
other words, the server MAY enforce that no operation violates the
lock even when operating in advisory mode.
The result is a SSH_FXP_STATUS return.
byte SSH_FXP_BLOCK
uint32 request-id
string handle
uint64 offset
uint64 length
uint32 uLockMask
handle
'handle' is an open file handle returned by SSH_FXP_OPEN. If
'handle' is not a handle returned by SSH_FXP_OPEN, the server MUST
return SSH_FX_INVALID_HANDLE.
offset
Beginning of the byte-range to lock.
length
Number of bytes in the range to lock. The special value 0 means
lock from 'offset' to the end of the file.
uLockMask
A bit mask of SSH_FXF_ACCESS_BLOCK_* values; the meanings are
described in Section 7.1.1.3.
The SSH_FXP_UNLOCK removes a previously aquired byte-range lock on
the specified handle.
The result is a SSH_FXP_STATUS return.
byte SSH_FXP_UNBLOCK
uint32 request-id
string handle
uint64 offset
uint64 length
handle
'handle' is an open file handle returned by SSH_FXP_OPEN. If
'handle' is not a handle returned by SSH_FXP_OPEN, the server MUST
return SSH_FX_INVALID_HANDLE.
offset
Beginning of the byte-range to lock.
length
Number of bytes in the range to lock. The special value 0 means
lock from 'offset' to the end of the file.
7.8 Canonicalizing the Server-Side Path Name 7.8 Canonicalizing the Server-Side Path Name
The SSH_FXP_REALPATH request can be used to have the server The SSH_FXP_REALPATH request can be used to have the server
canonicalize any given path name to an absolute path. This is useful canonicalize any given path name to an absolute path. This is useful
for converting path names containing ".." components or relative for converting path names containing ".." components or relative
pathnames without a leading slash into absolute paths. The format of pathnames without a leading slash into absolute paths. The format of
the request is as follows: the request is as follows:
byte SSH_FXP_REALPATH byte SSH_FXP_REALPATH
uint32 request-id uint32 request-id
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SSH_FXP_REALPATH_STAT_ALWAYS 0x00000003 SSH_FXP_REALPATH_STAT_ALWAYS 0x00000003
This field is optional, and if it is not present in the packet, it This field is optional, and if it is not present in the packet, it
is assumed to be SSH_FXP_REALPATH_NO_CHECK. is assumed to be SSH_FXP_REALPATH_NO_CHECK.
If SSH_FXP_REALPATH_NO_CHECK is specified, the server MUST NOT If SSH_FXP_REALPATH_NO_CHECK is specified, the server MUST NOT
fail the request if the path does not exist, is hidden, or the fail the request if the path does not exist, is hidden, or the
user does not have access to the path or some component thereof. user does not have access to the path or some component thereof.
However, the path MAY NOT be completely resolved to it's component However, the path MAY NOT be completely resolved to it's component
form. For example, symlinks may not be followed in this case. form. For example, symlinks may not be followed in this case.
The server MAY fail the request if the path is not syntactically
The server MAY fail the request if the path is not syntaticly
valid, or for other reasons. valid, or for other reasons.
If SSH_FXP_REALPATH_STAT_IF is specified, the server MUST stat the If SSH_FXP_REALPATH_STAT_IF is specified, the server MUST stat the
path if it exists and is accessible to the client. However, if path if it exists and is accessible to the client. However, if
the path does not exist, isn't visible, or isn't accessible, the the path does not exist, isn't visible, or isn't accessible, the
server MUST NOT fail the request. If the stat failed, the file server MUST NOT fail the request. If the stat failed, the file
type will be SSH_FILEXFER_TYPE_UNKNOWN. If the client needs to type will be SSH_FILEXFER_TYPE_UNKNOWN. If the client needs to
distinguish between files that are actually distinguish between files that are actually
SSH_FILEXFER_TYPE_UNKNOWN and paths that don't exist, it will SSH_FILEXFER_TYPE_UNKNOWN and paths that don't exist, it will
have to issue a seperate stat command in this case. have to issue a seperate stat command in this case.
If SSH_FXP_REALPATH_STAT_ALWAYS is specified the server MUST stat If SSH_FXP_REALPATH_STAT_ALWAYS is specified the server MUST stat
the path. If the stat operation fails, the server MUST fail the the path. If the stat operation fails, the server MUST fail the
request. request.
The server MUST take the 'original-path' and apply the 'compose-path' The server MUST take the 'original-path' and apply the 'compose-path'
as a modification to it. 'compose-path' MAY be relative to as a modification to it. 'compose-path' MAY be relative to 'original-
'original-path' or may be an absolute path, in which case path' or may be an absolute path, in which case 'original-path' will
'original-path' will be discarded. The 'compose-path' may be zero be discarded. The 'compose-path' may be zero length.
length.
The server will respond with a SSH_FXP_NAME packet containing the The server will respond with a SSH_FXP_NAME packet containing the
canonical form of the composite path. If SSH_FXP_REALPATH_NO_CHECK canonical form of the composite path. If SSH_FXP_REALPATH_NO_CHECK
is specified, the attributes are dummy values. is specified, the attributes are dummy values.
7.8.1 Best Practice for Dealing with Paths 7.8.1 Best Practice for Dealing with Paths
BEGIN: RFCEDITOR REMOVE BEFORE PUBLISHING BEGIN: RFCEDITOR REMOVE BEFORE PUBLISHING
Previous to this version, clients typically composed new paths Previous to this version, clients typically composed new paths
themselves and then called both realpath and stat on the resulting themselves and then called both realpath and stat on the resulting
path to get it's canonical name and see if it really existed and was path to get its canonical name and see if it really existed and was a
a directory. directory.
This required clients to assume certain things about how a relative This required clients to assume certain things about how a relative
vs. realpath looked. The new realpath allows clients to no longer vs. realpath looked. The new realpath allows clients to no longer
make those assumptions and to remove one round trip from the process make those assumptions and to remove one round trip from the process
and get deterministic behavior from all servers. and get deterministic behavior from all servers.
END: RFCEDITOR REMOVE BEFORE PUBLISHING END: RFCEDITOR REMOVE BEFORE PUBLISHING
The client SHOULD treat the results of SSH_FXP_REALPATH as a The client SHOULD treat the results of SSH_FXP_REALPATH as a
canonical absolute path, even if the path does not appear to be canonical absolute path, even if the path does not appear to be
absolute. A client that use REALPATH(".", "") and treats the result absolute. A client that uses REALPATH(".", "") and treats the result
as absolute, even if there is no leading slash, will continue to as absolute, even if there is no leading slash, will continue to
function correctly, even when talking to a Windows NT or VMS style function correctly, even when talking to a Windows NT or VMS style
system, where absolute paths may not begin with a slash. system, where absolute paths may not begin with a slash.
The client SHOULD also use SSH_FXP_REALPATH call to compose paths so The client SHOULD also use SSH_FXP_REALPATH call to compose paths so
that it does not need to know when a path is absolute or relative. that it does not need to know when a path is absolute or relative.
For example, if the client wishes to change directory up, and the For example, if the client wishes to change directory up, and the
server has returned "c:/x/y/z" from REALPATH, the client SHOULD use server has returned "c:/x/y/z" from REALPATH, the client SHOULD use
REALPATH("c:/x/y/z", "..", SSH_FXP_REALPATH_STAT_ALWAYS) REALPATH("c:/x/y/z", "..", SSH_FXP_REALPATH_STAT_ALWAYS)
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match each response with the corresponding request. Note that it is match each response with the corresponding request. Note that it is
legal to have several requests outstanding simultaneously, and the legal to have several requests outstanding simultaneously, and the
server is allowed to send responses to them in a different order from server is allowed to send responses to them in a different order from
the order in which the requests were sent (the result of their the order in which the requests were sent (the result of their
execution, however, is guaranteed to be as if they had been processed execution, however, is guaranteed to be as if they had been processed
one at a time in the order in which the requests were sent). one at a time in the order in which the requests were sent).
Response packets are of the same general format as request packets. Response packets are of the same general format as request packets.
Each response packet begins with the request identifier. Each response packet begins with the request identifier.
8.1 Status Response
The format of the data portion of the SSH_FXP_STATUS response is as The format of the data portion of the SSH_FXP_STATUS response is as
follows: follows:
byte SSH_FXP_STATUS byte SSH_FXP_STATUS
uint32 request-id uint32 request-id
uint32 error/status code uint32 error/status code
string error message (ISO-10646 UTF-8 [RFC-2279]) string error message (ISO-10646 UTF-8 [RFC-2279])
string language tag (as defined in [RFC-1766]) string language tag (as defined in [RFC-1766])
<error-specific data> error-specific data
request-id request-id
The 'request-id' specified by the client in the request the server The 'request-id' specified by the client in the request the server
is responding to. is responding to.
error/status code error/status code
Machine readable status code indicating the result of the request. Machine readable status code indicating the result of the request.
Error code values are defined below. The value SSH_FX_OK Error code values are defined below. The value SSH_FX_OK
indicates success, and all other values indicate failure. indicates success, and all other values indicate failure.
error message error message
Human readable description of the error. 'language tag' specifies Human readable description of the error.
the language the error is in.
language tag
'language tag' specifies the language the error is in.
<error-specific data> <error-specific data>
The error-specific data may be empty, or may contain additional The error-specific data may be empty, or may contain additional
information about the error. For error codes that send information about the error. For error codes that send error-
error-specific data, the format of the data is defined below. specific data, the format of the data is defined below.
Error codes: Error codes:
SSH_FX_OK 0 SSH_FX_OK 0
SSH_FX_EOF 1 SSH_FX_EOF 1
SSH_FX_NO_SUCH_FILE 2 SSH_FX_NO_SUCH_FILE 2
SSH_FX_PERMISSION_DENIED 3 SSH_FX_PERMISSION_DENIED 3
SSH_FX_FAILURE 4 SSH_FX_FAILURE 4
SSH_FX_BAD_MESSAGE 5 SSH_FX_BAD_MESSAGE 5
SSH_FX_NO_CONNECTION 6 SSH_FX_NO_CONNECTION 6
SSH_FX_CONNECTION_LOST 7 SSH_FX_CONNECTION_LOST 7
SSH_FX_OP_UNSUPPORTED 8 SSH_FX_OP_UNSUPPORTED 8
SSH_FX_INVALID_HANDLE 9 SSH_FX_INVALID_HANDLE 9
SSH_FX_NO_SUCH_PATH 10 SSH_FX_NO_SUCH_PATH 10
SSH_FX_FILE_ALREADY_EXISTS 11 SSH_FX_FILE_ALREADY_EXISTS 11
SSH_FX_WRITE_PROTECT 12 SSH_FX_WRITE_PROTECT 12
SSH_FX_NO_MEDIA 13 SSH_FX_NO_MEDIA 13
SSH_FX_NO_SPACE_ON_FILESYSTEM 14 SSH_FX_NO_SPACE_ON_FILESYSTEM 14
SSH_FX_QUOTA_EXCEEDED 15 SSH_FX_QUOTA_EXCEEDED 15
SSH_FX_UNKNOWN_PRINCIPLE 16 SSH_FX_UNKNOWN_PRINCIPAL 16
SSH_FX_LOCK_CONFLICT 17 SSH_FX_LOCK_CONFLICT 17
SSH_FX_DIR_NOT_EMPTY 18 SSH_FX_DIR_NOT_EMPTY 18
SSH_FX_NOT_A_DIRECTORY 19 SSH_FX_NOT_A_DIRECTORY 19
SSH_FX_INVALID_FILENAME 20 SSH_FX_INVALID_FILENAME 20
SSH_FX_LINK_LOOP 21 SSH_FX_LINK_LOOP 21
SSH_FX_CANNOT_DELETE 22 SSH_FX_CANNOT_DELETE 22
SSH_FX_INVALID_PARAMETER 23 SSH_FX_INVALID_PARAMETER 23
SSH_FX_FILE_IS_A_DIRECTORY 24 SSH_FX_FILE_IS_A_DIRECTORY 24
SSH_FX_BYTE_RANGE_LOCK_CONFLICT 25 SSH_FX_BYTE_RANGE_LOCK_CONFLICT 25
SSH_FX_BYTE_RANGE_LOCK_REFUSED 26 SSH_FX_BYTE_RANGE_LOCK_REFUSED 26
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the failure. the failure.
This error message SHOULD always have meaningful text in the the This error message SHOULD always have meaningful text in the the
'error message' field. 'error message' field.
SSH_FX_BAD_MESSAGE SSH_FX_BAD_MESSAGE
A badly formatted packet or other SFTP protocol incompatibility A badly formatted packet or other SFTP protocol incompatibility
was detected. was detected.
SSH_FX_NO_CONNECTION SSH_FX_NO_CONNECTION
There is no connection to the server. This error can only be There is no connection to the server. This error MAY be used
generated locally, and MUST NOT be return by a server. locally, but MUST NOT be return by a server.
SSH_FX_CONNECTION_LOST SSH_FX_CONNECTION_LOST
The connection to the server was lost. This error can only be The connection to the server was lost. This error MAY be used
generated locally, and MUST NOT be return by a server. locally, but MUST NOT be return by a server.
SSH_FX_OP_UNSUPPORTED SSH_FX_OP_UNSUPPORTED
An attempted operation could not be completed by the server An attempted operation could not be completed by the server
because the server does not support the operation. because the server does not support the operation.
This error MAY be generated locally by the client if e.g. the This error MAY be generated locally by the client if e.g. the
version number exchange indicates that a required feature is not version number exchange indicates that a required feature is not
supported by the server, or it may be returned by the server if supported by the server, or it may be returned by the server if
the server does not implement an operation). the server does not implement an operation).
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SSH_FX_NO_MEDIA SSH_FX_NO_MEDIA
The requested operation cannot be completed because there is no The requested operation cannot be completed because there is no
media available in the drive. media available in the drive.
SSH_FX_NO_SPACE_ON_FILESYSTEM SSH_FX_NO_SPACE_ON_FILESYSTEM
The requested operation cannot be completed because there is no The requested operation cannot be completed because there is no
free space on the filesystem. free space on the filesystem.
SSH_FX_QUOTA_EXCEEDED SSH_FX_QUOTA_EXCEEDED
The operation cannot be completed because the it would exceed the The operation cannot be completed because it would exceed the
users storage quota. user's storage quota.
SSH_FX_UNKNOWN_PRINCIPLE SSH_FX_UNKNOWN_PRINCIPAL
A principle referenced by the request (either the 'owner', A principal referenced by the request (either the 'owner',
'group', or 'who' field of an ACL), was unknown. The error 'group', or 'who' field of an ACL), was unknown. The error
specific data contains the problematic names. The format is one specific data contains the problematic names. The format is one
or more: or more:
string unknown-name string unknown-name
Each string contains the name of a principle that was unknown. Each string contains the name of a principle that was unknown.
SSH_FX_LOCK_CONFLICT SSH_FX_LOCK_CONFLICT
The file could not be opened because it is locked by another The file could not be opened because it is locked by another
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SSH_FX_INVALID_PARAMETER SSH_FX_INVALID_PARAMETER
On of the parameters was out of range, or the parameters specified On of the parameters was out of range, or the parameters specified
cannot be used together. cannot be used together.
SSH_FX_FILE_IS_A_DIRECTORY SSH_FX_FILE_IS_A_DIRECTORY
The specifed file was a directory in a context where a directory The specifed file was a directory in a context where a directory
cannot be used. cannot be used.
SSH_FX_BYTE_RANGE_LOCK_CONFLICT SSH_FX_BYTE_RANGE_LOCK_CONFLICT
A read or write operation failed because another process owns a Some operating systems support locking a range of bytes within a
byte range lock that conflicts. file. On such operating systems, it is possible for a SFTP
request to fail due to some other process owning a byte-range
lock, even though the SFTP protocol does not support byte-range
locks natively.
A read or write operation failed because another process's byte-
range lock overlaps with the request.
SSH_FX_BYTE_RANGE_LOCK_REFUSED SSH_FX_BYTE_RANGE_LOCK_REFUSED
A request for a byte range lock was refused. A request for a byte range lock was refused.
SSH_FX_DELETE_PENDING SSH_FX_DELETE_PENDING
An operation was attempted on a file for which a delete operation An operation was attempted on a file for which a delete operation
is pending. is pending.
SSH_FX_FILE_CORRUPT SSH_FX_FILE_CORRUPT
The file is corrupt; an filesystem integrity check should be run. The file is corrupt; an filesystem integrity check should be run.
8.2 Handle Response
The SSH_FXP_HANDLE response has the following format: The SSH_FXP_HANDLE response has the following format:
byte SSH_FXP_HANDLE byte SSH_FXP_HANDLE
uint32 request-id uint32 request-id
string handle string handle
'handle' 'handle'
An arbitrary string that identifies an open file or directory on An arbitrary string that identifies an open file or directory on
the server. The handle is opaque to the client; the client MUST the server. The handle is opaque to the client; the client MUST
NOT attempt to interpret or modify it in any way. The length of NOT attempt to interpret or modify it in any way. The length of
the handle string MUST NOT exceed 256 data bytes. the handle string MUST NOT exceed 256 data bytes.
8.3 Data Response
The SSH_FXP_DATA response has the following format: The SSH_FXP_DATA response has the following format:
byte SSH_FXP_DATA byte SSH_FXP_DATA
uint32 request-id uint32 request-id
string data string data
bool end-of-file [optional] bool end-of-file [optional]
data data
'data' is an arbitrary byte string containing the requested data. 'data' is an arbitrary byte string containing the requested data.
The data string may be at most the number of bytes requested in a The data string may be at most the number of bytes requested in a
SSH_FXP_READ request, but may also be shorter. (See SSH_FXP_READ request, but may also be shorter. (See
Section 7.2.1.) Section 7.2.1.)
end-of-file end-of-file
This field is optional. If it is present in the packet, it MUST This field is optional. If it is present in the packet, it MUST
be true, and it indicates that EOF was reached during this read. be true, and it indicates that EOF was reached during this read.
This can help the client avoid a round trip to determine whether a This can help the client avoid a round trip to determine whether a
short read was normal (due to EOF) or some other problem (limitted short read was normal (due to EOF) or some other problem (limited
server buffer for example.) server buffer for example.)
8.4 Name Response
The SSH_FXP_NAME response has the following format: The SSH_FXP_NAME response has the following format:
byte SSH_FXP_NAME byte SSH_FXP_NAME
uint32 request-id uint32 request-id
uint32 count uint32 count
repeats count times: repeats count times:
string filename [UTF-8] string filename [UTF-8]
ATTRS attrs ATTRS attrs
bool end-of-list [optional] bool end-of-list [optional]
count count
The number of names returned in this response, and the remaining The number of names returned in this response, and the 'filename'
fields repeat 'count' times. and 'attrs' field repeat 'count' times.
filename filename
A file name being returned (for SSH_FXP_READDIR, it will be a A file name being returned (for SSH_FXP_READDIR, it will be a
relative name within the directory, without any path components; relative name within the directory, without any path components;
for SSH_FXP_REALPATH it will be an absolute path name.) for SSH_FXP_REALPATH it will be an absolute path name.)
attrs attrs
The attributes of the file as described in Section ''File The attributes of the file as described in Section ''File
Attributes''. Attributes''.
end-of-list end-of-list
This field is optional. If present in the packet, it MUST be This field is optional. If present in the packet, it MUST be
true, and indicates that there are no more entries to be read. true, and indicates that there are no more entries to be read.
This can save the client a round trip to determine if there are This can save the client a round trip to determine if there are
more entries to be read. more entries to be read.
8.5 Attrs Response
The SSH_FXP_ATTRS response has the following format: The SSH_FXP_ATTRS response has the following format:
byte SSH_FXP_ATTRS byte SSH_FXP_ATTRS
uint32 request-id uint32 request-id
ATTRS attrs ATTRS attrs
where 'request-id' is the request identifier, and 'attrs' is the attrs
returned file attributes as described in Section ''File Attributes''. The returned file attributes as described in Section ''File
Attributes''.
9. Extensions 9. Extensions
The SSH_FXP_EXTENDED request provides a generic extension mechanism The SSH_FXP_EXTENDED request provides a generic extension mechanism
for adding additional commands. for adding additional commands.
byte SSH_FXP_EXTENDED byte SSH_FXP_EXTENDED
uint32 request-id uint32 request-id
string extended-request string extended-request
... any request-specific data ... ... any request-specific data ...
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extended-request extended-request
A string naming the extension. Vendor-specific extensions have A string naming the extension. Vendor-specific extensions have
use the "name@domain" syntax, where domain is an internet domain use the "name@domain" syntax, where domain is an internet domain
name of the vendor defining the request. name of the vendor defining the request.
The IETF may also define extensions to the protocol. These The IETF may also define extensions to the protocol. These
extension names will not have an '@' in them. extension names will not have an '@' in them.
request-specific data request-specific data
The rest of the request is defined by the extension, and servers The rest of the request is defined by the extension; servers
should only attempt to interpret it if they recognize the SHOULD NOT attempt to interpret it if they do not recognize the
'extended-request' name. 'extended-request' name.
The server may respond to such requests using any of the response The server may respond to such requests using any of the response
packets defined in Section ''Responses from the Server to the packets defined in Section ''Responses from the Server to the
Client''. Additionally, the server may also respond with a Client''. Additionally, the server may also respond with a
SSH_FXP_EXTENDED_REPLY packet, as defined below. If the server does SSH_FXP_EXTENDED_REPLY packet, as defined below. If the server does
not recognize the 'extended-request' name, then the server MUST not recognize the 'extended-request' name, then the server MUST
respond with SSH_FXP_STATUS with error/status set to respond with SSH_FXP_STATUS with error/status set to
SSH_FX_OP_UNSUPPORTED. SSH_FX_OP_UNSUPPORTED.
skipping to change at page 45, line 12 skipping to change at page 50, line 18
uint32 request-id uint32 request-id
... any request-specific data ... ... any request-specific data ...
There is a range of packet types reserved for use by extensions. In There is a range of packet types reserved for use by extensions. In
order to avoid collision, extensions that that use additional packet order to avoid collision, extensions that that use additional packet
types should determine those numbers dynamically. types should determine those numbers dynamically.
The suggested way of doing this is have an extension request from the The suggested way of doing this is have an extension request from the
client to the server that enables the extension; the extension client to the server that enables the extension; the extension
response from the server to the client would specify the actual type response from the server to the client would specify the actual type
values to use, in additional to any other data. values to use, in addition to any other data.
Extension authors should be mindful of the limited range of packet Extension authors should be mindful of the limited range of packet
types available (there are only 45 values available) and avoid types available (there are only 45 values available) and avoid
requiring a new packet type where possible. requiring a new packet type where possible.
9.1 File Hashing 9.1 File Hashing
BEGIN: RFCEDITOR REMOVE BEFORE PUBLISHING BEGIN: RFCEDITOR REMOVE BEFORE PUBLISHING
After some discussion of this at connectathon, I know of two uses for After some discussion of this at connectathon, I know of two uses for
skipping to change at page 47, line 43 skipping to change at page 53, line 9
'handle' is an open file handle returned by SSH_FXP_OPEN. If 'handle' is an open file handle returned by SSH_FXP_OPEN. If
'handle' is not a handle returned by SSH_FXP_OPEN, the server MUST 'handle' is not a handle returned by SSH_FXP_OPEN, the server MUST
return SSH_FX_INVALID_HANDLE. If ACE4_READ_DATA MUST was not return SSH_FX_INVALID_HANDLE. If ACE4_READ_DATA MUST was not
included when the file was opened, the server MUST return included when the file was opened, the server MUST return
STATUS_PERMISSION_DENIED. STATUS_PERMISSION_DENIED.
If this file handle was opened in TEXT mode, the check must be If this file handle was opened in TEXT mode, the check must be
performed on the data as it would be sent on the wire. performed on the data as it would be sent on the wire.
hash-algorithm-list hash-algorithm-list
A comma seperated list of hash alogirthms the client is willing to A comma separated list of hash alogirthms the client is willing to
accept for this operation. The server MUST pick the first hash on accept for this operation. The server MUST pick the first hash on
the list that it supports. the list that it supports.
Currently supported algorithms are "md5", "sha1", "sha224", Currently supported algorithms are "md5", "sha1", "sha224",
"sha256", "sha384", "sha512", and "crc32". Additional algorithms "sha256", "sha384", "sha512", and "crc32". Additional algorithms
may be added by following the DNS extensibility naming convention may be added by following the DNS extensibility naming convention
outlined in [I-D.ietf-secsh-architecture]. outlined in [I-D.ietf-secsh-architecture].
MD5 is described in [RFC1321]. SHA-1, SHA-224, SHA-256, SHA-384, MD5 is described in [RFC1321]. SHA-1, SHA-224, SHA-256, SHA-384,
and SHA-512 are decribed in [FIPS-180-2]. crc32 is described in and SHA-512 are decribed in [FIPS-180-2]. crc32 is described in
[ISO.3309.1991], and is the same algorithm used in [RFC1510] [ISO.3309.1991], and is the same algorithm used in [RFC1510]
start-offset start-offset
The starting offset of the data to include in the hash. The starting offset of the data to include in the hash.
length length
The length of data to include in the hash. If length is zero, all The length of data to include in the hash. If length is zero, all
the data from start-offset to the end-of-file should be included. the data from start-offset to the end-of-file should be included.
block-size block-size
An independant hash MUST be computed over ever block in the file. An independant hash MUST be computed over every block in the file.
The size of blocks is specified by block-size. The block-size The size of blocks is specified by block-size. The block-size
MUST NOT be smaller than 256 bytes. If the block-size is 0, then MUST NOT be smaller than 256 bytes. If the block-size is 0, then
only one hash, over the entire range MUST be made. only one hash, over the entire range, MUST be made.
The response is either a SSH_FXP_STATUS packet, indicating an error, The response is either a SSH_FXP_STATUS packet, indicating an error,
or the following extended reply packet: or the following extended reply packet:
byte SSH_FXP_EXTENDED_REPLY byte SSH_FXP_EXTENDED_REPLY
uint32 request-id uint32 request-id
string "check-file" string "check-file"
string hash-algo-used string hash-algo-used
byte hash[n][block-count] byte hash[n][block-count]
hash-algo-used hash-algo-used
The hash algorithm that was actually used. The hash algorithm that was actually used.
hash hash
The computed hashes. The hash algorithm used determines the size The computed hashes. The hash algorithm used determines the size
of n. The number of block-size chunks of data in the file of n. The number of block-size chunks of data in the file
determines block-count. The hashes are placed in the packet one determines block-count. The hashes are placed in the packet one
after another, with no decoration. after another, with no decoration.
Note that if the length of the range is not an even multiple of Note that if the length of the range is not an even multiple of
block-size, the last hash will have been computer over only the block-size, the last hash will have been computed over only the
remainder of the range instead of a full block. remainder of the range instead of a full block.
9.2 Querying Available Space 9.2 Querying Available Space
The following extension provides a way to discover the available The following extension provides a way to discover the available
space for an arbitrary path. space for an arbitrary path.
byte SSH_FXP_EXTENDED byte SSH_FXP_EXTENDED
uint32 request-id uint32 request-id
string "space-available" string "space-available"
skipping to change at page 49, line 26 skipping to change at page 54, line 39
uint64 unused-bytes-on-device uint64 unused-bytes-on-device
uint64 bytes-available-to-user uint64 bytes-available-to-user
uint64 unused-bytes-available-to-user uint64 unused-bytes-available-to-user
uint32 bytes-per-allocation-unit uint32 bytes-per-allocation-unit
bytes-on-device bytes-on-device
The total number of bytes on the device which stores 'path', both The total number of bytes on the device which stores 'path', both
used and unused, or 0 if unknown. used and unused, or 0 if unknown.
unused-bytes-on-device unused-bytes-on-device
The total number of unused bytes availabe on the device which The total number of unused bytes available on the device which
stores 'path', or 0 if unknown. stores 'path', or 0 if unknown.
bytes-available-to-user bytes-available-to-user
The total number of bytes, both used and unused, available to the The total number of bytes, both used and unused, available to the
authenticated user on the device which stores 'path', or 0 if authenticated user on the device which stores 'path', or 0 if
unknown. unknown.
unused-bytes-available-to-user unused-bytes-available-to-user
The total number of unused bytes available to the authenticated The total number of unused bytes available to the authenticated
user on the device which stores 'path', or 0 if unknown. user on the device which stores 'path', or 0 if unknown.
bytes-per-allocation-unit bytes-per-allocation-unit
The number of bytes in each allocation unit on the device, or in The number of bytes in each allocation unit on the device, or in
other words, the minimum number of bytes that a file allocation other words, the minimum number of bytes that a file allocation
size can grow or shrink by. If the server does not know this size can grow or shrink by. If the server does not know this
information, or the file-system in use does not use allocation information, or the file-system in use does not use allocation
block, this value MUST be 0. blocks, this value MUST be 0.
9.3 Querying User Home Directory 9.3 Querying User Home Directory
Many users are used to being able to type '~' as an alias for their Many users are used to being able to type '~' as an alias for their
home directory, or ~username as an alias for another user's home home directory, or ~username as an alias for another user's home
directory. To support this feature, a server MAY support following directory. To support this feature, a server MAY support following
extension. extension.
byte SSH_FXP_EXTENDED byte SSH_FXP_EXTENDED
uint32 request-id uint32 request-id
skipping to change at page 50, line 23 skipping to change at page 55, line 37
The reply to the request is either a SSH_FXP_STATUS packet or the The reply to the request is either a SSH_FXP_STATUS packet or the
following extended reply: following extended reply:
byte SSH_FXP_EXTENDED_REPLY byte SSH_FXP_EXTENDED_REPLY
uint32 request-id uint32 request-id
string "home-directory" string "home-directory"
string absolute-pathname string absolute-pathname
absolute-pathname absolute-pathname
Absolute pathname of the specified user's home directory. Absolute pathname of the specified user's home directory, suitable
for use in operations such as REALPATH or OPEN.
10. Implementation Considerations 10. Implementation Considerations
In order for this protocol to perform well, especially over high In order for this protocol to perform well, especially over high
latency networks, multiple read and write requests should be queued latency networks, multiple read and write requests should be queued
to the server. to the server.
The data size of requests should match the maximum packet size for The data size of requests should match the maximum packet size for
the next layer up in the protocol chain. the next layer up in the protocol chain.
When implemented over ssh, the best performance should be achieved When implemented over ssh, the best performance should be achieved
when the data size matches the channels max packet, and the channel when the data size matches the channel's max packet, and the channel
window is a multiple of the channel packet size. window is a multiple of the channel packet size.
Implementations MUST be aware that requests do not have to be Implementations MUST be aware that requests do not have to be
satisfied in the order issued. (See Request Synchronization and satisfied in the order issued. (See Request Synchronization and
Reordering (Section 3.1).) Reordering (Section 3.1).)
Implemenations MUST also be aware that read requests may not return Implementations MUST also be aware that read requests may not return
all the requested data, even if the data is available. all the requested data, even if the data is available.
11. Security Considerations 11. Security Considerations
It is assumed that both ends of the connection have been It is assumed that both ends of the connection have been
authenticated and that the connection has privacy and integrity authenticated and that the connection has privacy and integrity
features. Such security issues are left to the underlying transport features. Such security issues are left to the underlying transport
protocol, except to note that if this is not the case, an attacker protocol, except to note that if this is not the case, an attacker
could manipulate files on the server at will and thus wholly could manipulate files on the server at will and thus wholly
compromise the server. compromise the server.
This protocol provides file system access to arbitrary files on the This protocol provides file system access to arbitrary files on the
server (only constrained by the server implementation). It is the server (constrained only by the server implementation). It is the
responsibility of the server implementation to enforce any access responsibility of the server implementation to enforce any access
controls that may be required to limit the access allowed for any controls that may be required to limit the access allowed for any
particular user (the user being authenticated externally to this particular user (the user being authenticated externally to this
protocol, typically using [I-D.ietf-secsh-userauth]. protocol, typically using [I-D.ietf-secsh-userauth].
Extreme care must be used when interpreting file handle strings. In Extreme care must be used when interpreting file handle strings. In
particular, care must be taken that a file handle string is valid in particular, care must be taken that a file handle string is valid in
the context of a given 'file-share' session. For example, the the context of a given 'file-share' session. For example, the 'file-
'file-share' server daemon may have files which it has opened for its share' server daemon may have files which it has opened for its own
own purposes, and the client must not be able to access these files purposes, and the client must not be able to access these files by
by specifying an arbitrary file handle string. specifying an arbitrary file handle string.
The permission field of the attrib structure (Section 6.6) may The permission field of the attrib structure (Section 6.6) may
include the SUID, SGID, and SVTX (sticky) bits. Clients should use include the SUID, SGID, and SVTX (sticky) bits. Clients should use
extreme caution when setting these bits on either remote or local extreme caution when setting these bits on either remote or local
files. (I.e., just because a file was SUID on the remote system does files. (I.e., just because a file was SUID on the remote system does
not necessarily imply that it should be SUID on the local system.) not necessarily imply that it should be SUID on the local system.)
Filesystems often contain entries for objects that are not files at Filesystems often contain entries for objects that are not files at
all, but are rather devices. For example, it may be possible to all, but are rather devices. For example, it may be possible to
access serial ports, tape devices, or named pipes using this access serial ports, tape devices, or named pipes using this
skipping to change at page 51, line 43 skipping to change at page 57, line 11
time while I/O is performed to such a device. time while I/O is performed to such a device.
Servers should take care that file-system quotas are respected for Servers should take care that file-system quotas are respected for
users. In addition, implementations should be aware that attacks may users. In addition, implementations should be aware that attacks may
be possible, or facilitated, by filling a filesystem. For example, be possible, or facilitated, by filling a filesystem. For example,
filling the filesystem where event logging and auditing occurs may, filling the filesystem where event logging and auditing occurs may,
at best, cause the system to crash, or at worst, allow the attacker at best, cause the system to crash, or at worst, allow the attacker
to take untraceable actions in the future. to take untraceable actions in the future.
Servers should take care that filenames are in their appropriate Servers should take care that filenames are in their appropriate
canonical form, and to insure that filenames not in canonical form canonical form, and to ensure that filenames not in canonical form
cannot be used to bypass access checks or controls. cannot be used to bypass access checks or controls.
If the server implementation limits access to certain parts of the If the server implementation limits access to certain parts of the
file system, extra care must be taken in parsing file names which file system, extra care must be taken in parsing file names which
contain the '..' path element, and when following symbolic links, contain the '..' path element, and when following symbolic links,
shortcuts, or other filesystem objects which might transpose the path shortcuts, or other filesystem objects which might transpose the path
to refer to an object outside of the restricted area. There have to refer to an object outside of the restricted area. There have
been numerous reported security bugs where a ".." in a path name has been numerous reported security bugs where a ".." in a path name has
allowed access outside the intended area. allowed access outside the intended area.
skipping to change at page 52, line 34 skipping to change at page 58, line 4
o Added allocation-size, text-hint, link-count, mime-type, and o Added allocation-size, text-hint, link-count, mime-type, and
untranslated-name fields to attrib structure. Add untranslated-name fields to attrib structure. Add
ATTR_FLAGS_TRANSLATION_ERR to the attrib-bits. ATTR_FLAGS_TRANSLATION_ERR to the attrib-bits.
o Add optional 'compose-path' and 'control-byte' to REALPATH; make o Add optional 'compose-path' and 'control-byte' to REALPATH; make
realpath's behaviour truly deterministic (i.e., MUST instead of realpath's behaviour truly deterministic (i.e., MUST instead of
SHOULD.) Give clients the ability to compose path's without SHOULD.) Give clients the ability to compose path's without
understanding what is relative and what is absolute. understanding what is relative and what is absolute.
o Give SSH_FXP_DATA and SSH_FXP_NAME optional end-of-data-set flags, o Give SSH_FXP_DATA and SSH_FXP_NAME optional end-of-data-set flags,
which can help the client avoid a round trip during normal which can help the client avoid a round trip during normal
operation. operation.
o Changed the SYMLINK packet to be LINK and give it the ability to o Changed the SYMLINK packet to be LINK and give it the ability to
create hard links. Also change it's packet number because many create hard links. Also change it's packet number because many
implementation implemented SYMLINK with the arguments reversed. implementation implemented SYMLINK with the arguments reversed.
Hopefully the new argument names make it clear which way is which. Hopefully the new argument names make it clear which way is which.
o Clarify who should apply umask to posix mode bits (the client, not o Clarify who should apply umask to POSIX mode bits (the client, not
the server.) the server.)
o Specify behavior for otherwise valid packets with excess data and o Specify behavior for otherwise valid packets with excess data and
unrecognized packet types. unrecognized packet types.
o Add home directory extension. o Add home directory extension.
o Remove "#define" from symbol definitions to shorten line and help o Remove "#define" from symbol definitions to shorten line and help
us pass idnits. us pass idnits.
o Change "supported" extension to "supported2", remove desired-
access-bits, seperate attrib extension from SSH_FXP_EXTENDED
extensions.
o Add "vendor-id" extension.
o Add ctime and attrib-bits-valid to attrib structure.
o Unrecognized attrib extensions cause failure rather than ignored.
o Option 'end of data' flags on data ane names responses.
12.2 Changes Between Versions 5 and 4 12.2 Changes Between Versions 5 and 4
Many of the changes between version 5 and version 4 are to better Many of the changes between version 5 and version 4 are to better
support the changes in version 4, and to better specify error support the changes in version 4, and to better specify error
conditions. conditions.
o Add "supported" extension to communicate features supported. o Add "supported" extension to communicate features supported.
o Clarify error handling when client requests unsupported feature. o Clarify error handling when client requests unsupported feature.
(For example, attempts to write an unsupported attribute.) (For example, attempts to write an unsupported attribute.)
o Add attrib-bits field to the attribute structure, which specifies o Add attrib-bits field to the attribute structure, which specifies
a number of boolean attributes related to files and directories, a number of boolean attributes related to files and directories,
including advisory read-only and case-sensitivity bits. including advisory read-only and case-sensitivity bits.
o Clarify the actual bit values to be used for the permissions field o Clarify the actual bit values to be used for the permissions field
(since posix doesn't define values) and correct the value of (since POSIX doesn't define values) and correct the value of
ATTR_PERMISSIONS flag. ATTR_PERMISSIONS flag.
o Some reordering of sections to attempt to get a better grouping of o Some reordering of sections to attempt to get a better grouping of
related functionality. related functionality.
o Open request explicitly specifies the access desired for the file. o Open request explicitly specifies the access desired for the file.
o Add support for explicitly requesting file locking. o Add support for explicitly requesting file locking.
o Add support for better control of the rename operation. o Add support for better control of the rename operation.
o Add SSH_FX_NO_SPACE_ON_FILESYSTEM, SSH_FX_QUOTA_EXCEEDED, and o Add SSH_FX_NO_SPACE_ON_FILESYSTEM, SSH_FX_QUOTA_EXCEEDED, and
SSH_FX_UNKNOWN_PRINCIPLE error codes. SSH_FX_UNKNOWN_PRINCIPLE error codes.
o Add support for error specific data. This is used by a new o Add support for error specific data. This is used by a new
SSH_FX_UNKNOWN_PRINCIPLE error to communicate which principles are SSH_FX_UNKNOWN_PRINCIPLE error to communicate which principles are
skipping to change at page 54, line 23 skipping to change at page 59, line 48
message' and 'language tag'. message' and 'language tag'.
12.5 Changes Between Versions 2 and 1 12.5 Changes Between Versions 2 and 1
o The SSH_FXP_RENAME message was added. o The SSH_FXP_RENAME message was added.
12.6 Changes Between Versions 1 and 0 12.6 Changes Between Versions 1 and 0
o Implementation changes, no actual protocol changes. o Implementation changes, no actual protocol changes.
13. Trademark Issues 13. References
"ssh" is a registered trademark of SSH Communications Security Corp
in the United States and/or other countries.
14. References
14.1 Normative References 13.1 Normative References
[RFC1321] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, [RFC1321] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321,
April 1992. April 1992.
[RFC1510] Kohl, J. and B. Neuman, "The Kerberos Network [RFC1510] Kohl, J. and B. Neuman, "The Kerberos Network
Authentication Service (V5)", RFC 1510, September 1993. Authentication Service (V5)", RFC 1510, September 1993.
[RFC3010] Shepler, S., Callaghan, B., Robinson, D., Thurlow, R., [RFC3010] Shepler, S., Callaghan, B., Robinson, D., Thurlow, R.,
Beame, C., Eisler, M. and D. Noveck, "NFS version 4 Beame, C., Eisler, M., and D. Noveck, "NFS version 4
Protocol", RFC 3010, December 2000. Protocol", RFC 3010, December 2000.
[I-D.ietf-secsh-architecture] [I-D.ietf-secsh-architecture]
Lonvick, C., "SSH Protocol Architecture", Lonvick, C., "SSH Protocol Architecture",
Internet-Draft draft-ietf-secsh-architecture-22, March draft-ietf-secsh-architecture-22 (work in progress),
2005. March 2005.
[I-D.ietf-secsh-transport] [I-D.ietf-secsh-transport]
Lonvick, C., "SSH Transport Layer Protocol", Lonvick, C., "SSH Transport Layer Protocol",
Internet-Draft draft-ietf-secsh-transport-24, March 2005. draft-ietf-secsh-transport-24 (work in progress),
March 2005.
[I-D.ietf-secsh-connect] [I-D.ietf-secsh-connect]
Lonvick, C., "SSH Connection Protocol", Lonvick, C., "SSH Connection Protocol",
Internet-Draft draft-ietf-secsh-connect-25, March 2005. draft-ietf-secsh-connect-25 (work in progress),
March 2005.
[IEEE.1003-1.1996] [IEEE.1003-1.1996]
Institute of Electrical and Electronics Engineers, Institute of Electrical and Electronics Engineers,
"Information Technology - Portable Operating System "Information Technology - Portable Operating System
Interface (POSIX) - Part 1: System Application Program Interface (POSIX) - Part 1: System Application Program
Interface (API) [C Language]", IEEE Standard 1003.2, 1996. Interface (API) [C Language]", IEEE Standard 1003.2, 1996.
[FIPS-180-2] [FIPS-180-2]
National Institute of Standards and Technology, "Secure National Institute of Standards and Technology, "Secure
Hash Standard (SHS)", Federal Information Processing Hash Standard (SHS)", Federal Information Processing
Standards Publication 180-2, August 2002. Standards Publication 180-2, August 2002.
[ISO.3309.1991] [ISO.3309.1991]
International Organization for Standardization, International Organization for Standardization,
"Information Technology - Telecommunications and "Information Technology - Telecommunications and
information exchange between systems - High-level data information exchange between systems - High-level data
link control (HDLC) procedures - Frame structure", link control (HDLC) procedures - Frame structure",
ISO Standard 3309, June 1991. ISO Standard 3309, June 1991.
14.2 Informative References 13.2 Informative References
[RFC1521] Borenstein, N. and N. Freed, "MIME (Multipurpose Internet [RFC1521] Borenstein, N. and N. Freed, "MIME (Multipurpose Internet
Mail Extensions) Part One: Mechanisms for Specifying and Mail Extensions) Part One: Mechanisms for Specifying and
Describing the Format of Internet Message Bodies", Describing the Format of Internet Message Bodies",
RFC 1521, September 1993. RFC 1521, September 1993.
[RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", [RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
RFC 2246, January 1999. RFC 2246, January 1999.
[RFC2277] Alvestrand, H., "IETF Policy on Character Sets and [RFC2277] Alvestrand, H., "IETF Policy on Character Sets and
Languages", BCP 18, RFC 2277, January 1998. Languages", BCP 18, RFC 2277, January 1998.
[I-D.ietf-secsh-userauth] [I-D.ietf-secsh-userauth]
Lonvick, C., "SSH Authentication Protocol", Lonvick, C., "SSH Authentication Protocol",
Internet-Draft draft-ietf-secsh-userauth-27, March 2005. draft-ietf-secsh-userauth-27 (work in progress),
March 2005.
Authors' Addresses Authors' Addresses
Joseph Galbraith Joseph Galbraith
VanDyke Software VanDyke Software
4848 Tramway Ridge Blvd 4848 Tramway Ridge Blvd
Suite 101 Suite 101
Albuquerque, NM 87111 Albuquerque, NM 87111
US US
 End of changes. 

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