draft-ietf-kitten-channel-bound-flag-01.txt   draft-ietf-kitten-channel-bound-flag-02.txt 
KITTEN N. Williams KITTEN R. Harwood
Internet-Draft Cryptonector Internet-Draft Red Hat
Updates: 2743, 2744 (if approved) March 30, 2017 Updates: 2743, 2744 (if approved) N. Williams
Intended status: Standards Track Intended status: Standards Track Cryptonector
Expires: October 1, 2017 Expires: April 8, 2018 October 5, 2017
Channel Binding Signalling for the Generic Security Services Application Channel Binding Signalling for the Generic Security Services Application
Programming Interface Programming Interface
draft-ietf-kitten-channel-bound-flag-01 draft-ietf-kitten-channel-bound-flag-02
Abstract Abstract
Channel binding is a technique that allows applications to use a Channel binding is a technique that allows applications to use a
secure channel at a lower layer without having to use authentication secure channel at a lower layer without having to use authentication
at that lower layer. The concept of channel binding comes from the at that lower layer. The concept of channel binding comes from the
Generic Security Services Application Programming Interface (GSS- Generic Security Services Application Programming Interface (GSS-
API). It turns out that the semantics commonly implemented are API). It turns out that the semantics commonly implemented are
different that those specified in the base GSS-API RFC (RFC2743), and different than those specified in the base GSS-API RFC (RFC2743), and
that that specification has a serious bug. This document addresses that that specification has a serious bug. This document addresses
both, the inconsistency as-implemented and the specification bug. both the inconsistency as-implemented and the specification bug.
This Internet-Draft proposes the addition of a "channel bound" return This Internet-Draft proposes the addition of a "channel bound" return
flag for the GSS_Init_sec_context() and GSS_Accept_sec_context() flag for the GSS_Init_sec_context() and GSS_Accept_sec_context()
functions. Two behaviors are specified: a default, safe behavior functions. Two behaviors are specified: a default, safe behavior
reflecting existing implementation deployments, and a behavior that reflecting existing implementation deployments, and a behavior that
is only safe when the application specifically tells the GSS-API that is only safe when the application specifically tells the GSS-API that
it (the application) supports the new behavior. Additional API it (the application) supports the new behavior. Additional API
elements related to this are also added, including a new security elements related to this are also added, including a new security
context establishment API. context establishment API.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 1, 2017. This Internet-Draft will expire on April 8, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Error in RFC2743 . . . . . . . . . . . . . . . . . . . . . 3 1.1. Design and Future directions . . . . . . . . . . . . . . . 3
1.2. Design . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2. Conventions used in this document . . . . . . . . . . . . . 3
1.3. Alternative Design . . . . . . . . . . . . . . . . . . . . 4 2. Channel Binding State Extension . . . . . . . . . . . . . . . 4
1.4. Future Directions . . . . . . . . . . . . . . . . . . . . . 4 2.1. GSS_Create_sec_context() . . . . . . . . . . . . . . . . . 4
1.5. Conventions used in this document . . . . . . . . . . . . . 4 2.1.1. C-Bindings . . . . . . . . . . . . . . . . . . . . . . . 4
2. Channel Binding State Extension . . . . . . . . . . . . . . . 5 2.2. GSS_Set_context_flags() . . . . . . . . . . . . . . . . . . 5
2.1. GSS_Create_sec_context() . . . . . . . . . . . . . . . . . 5 2.2.1. C-Bindings . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.1. C-Bindings . . . . . . . . . . . . . . . . . . . . . . . 5 2.3. Return Flag for Channel Binding State Signalling . . . . . 6
2.2. GSS_Set_context_flags() . . . . . . . . . . . . . . . . . . 6 2.3.1. C-Bindings . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.1. C-Bindings . . . . . . . . . . . . . . . . . . . . . . . 6 2.4. New Mechanism Attributes . . . . . . . . . . . . . . . . . 6
2.3. Return Flag for Channel Binding State Signalling . . . . . 7 2.5. Request Flag for Acceptor Confirmation of Channel Binding . 6
2.3.1. C-Bindings . . . . . . . . . . . . . . . . . . . . . . . 7 2.5.1. C-Bindings . . . . . . . . . . . . . . . . . . . . . . . 7
2.4. New Mechanism Attributes . . . . . . . . . . . . . . . . . 7 2.6. Handling Empty Contexts in Other GSS-API Functions . . . . 7
2.5. Request Flag for Acceptor Confirmation of Channel Binding . 7 3. Modified Channel Binding Semantics . . . . . . . . . . . . . 7
2.5.1. C-Bindings . . . . . . . . . . . . . . . . . . . . . . . 8 4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
2.6. GSS_Delete_sec_context() Behavior When Applied to Empty 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
Security Contexts . . . . . . . . . . . . . . . . . . . . . 8 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
3. Modified Channel Binding Semantics . . . . . . . . . . . . . 8 6.1. Normative References . . . . . . . . . . . . . . . . . . . 8
4. Security Considerations . . . . . . . . . . . . . . . . . . . 9 6.2. Informative References . . . . . . . . . . . . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.1. Normative References . . . . . . . . . . . . . . . . . . . 9
6.2. Informative References . . . . . . . . . . . . . . . . . . 10
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction 1. Introduction
The GSS-API [RFC2743] supports "channel binding" [RFC5056], a The GSS-API [RFC2743] supports "channel binding" [RFC5056], a
technique for detection of man-in-the-middle (MITM) attacks in secure technique for detection of man-in-the-middle (MITM) attacks in secure
channels at lower network layers. This facility is meant to be all- channels at lower network layers. This facility is meant to be all-
or-nothing: either both the initiator and acceptor use it and it or-nothing: either both the initiator and acceptor use it and it
succeeds, or both must not use it. This has created a negotiation succeeds, or both must not use it. This has created a negotiation
problem when retrofitting the use of channel binding into existing problem when retrofitting the use of channel binding into existing
application protocols. application protocols.
Many implementations of the Kerberos V5 GSS-API mechanism [RFC4121] However, GSS-APIv2u1 [RFC2743] does not specify channel binding
cause the acceptor to succeed when the initiator used channel binding behavior when only one party provides provides none. In practice
but the acceptor application did not. This has helped deployment of some mechanisms ignore channel bindings when the acceptor provides
channel binding in existing applications: first fix all the none, but not when the initiator provides none. [XXX add references
initiators, then fix all the acceptors. But even this technique is to the relevant SSPI docs? -Nico] Note that it would be useless to
insufficient when there are many clients to fix, such that fixing allow security context establishment to succeed when the initiator
them all will take a long time. does not provide channel bindings but the acceptor does, at least as
long as there's no outward indication of whether channel binding was
used! Since the GSS-APIv2u1 does not provide any such indication,
this document corrects that flaw.
Allowing the connection to succeed when an initiator provides
bindings but an acceptor does not has helped deployment of channel
binding in existing applications: first fix all the initiators, then
fix all the acceptors. But even this technique is insufficient when
there are many clients to fix, such that fixing them all will take a
long time. Additionally, it limits the usefulness of channel
bindings, while allowing the acceptor to provide but not enforce
would protect against man in the middle attacks (for channel binding
aware initiators).
This document proposes a new method for deployment of channel binding This document proposes a new method for deployment of channel binding
that allows the feature to be enabled on the acceptor side before that allows the feature to be enabled on the acceptor side before
fixing all initiators. If the GSS-API had always had a return flag fixing all initiators. If the GSS-API had always had a return flag
by which to indicate channel binding state then we could have had a by which to indicate channel binding state then we could have had a
simpler method of deploying channel binding: applications check that simpler method of deploying channel binding: applications check that
return flag and act accordingly (e.g., fail when channel binding is return flag and act accordingly (e.g., fail when channel binding is
required). We cannot safely introduce this behavior now without an required). We cannot safely introduce this behavior now without an
indication of support by the application. indication of support by the application.
It is worth noting that at least one implementor of GSS-API
mechanisms (but not of the GSS-API itself) has similar semantics in
its API to those proposed herein. [XXX add references to the
relevant SSPI docs? -Nico]
Additionally, there may be applications where it is important for Additionally, there may be applications where it is important for
initiators to know that acceptors did use channel binding, and even initiators to know that acceptors did use channel binding, and even
to know whether a mechanism is capable of indicating as much. We add to know whether a mechanism is capable of indicating as much. We add
a request flag and two mechanism attributes for such applications. a request flag and two mechanism attributes for such applications.
1.1. Error in RFC2743 1.1. Design and Future directions
The GSS-APIv2u1 [RFC2743] seems to indicate that mechanisms must
ignore channel bindings when one party provided none. In practice
some mechanisms ignore channel bindings when the acceptor provides
none, but not when the initiator provides none. Note that it would
be useless to allow security context establishment to succeed when
the initiator does not provide channel bindings but the acceptor
does, at least as long as there's no outward indication of whether
channel binding was used! And indeed, the GSS-APIv2u1 does not
provide any such indication. We correct this flaw in this document.
1.2. Design
After some discussion on the mailing list of various designs for
signalling application support for the new flag we've settled on
copying an aspect of the Java Bindings of the GSS-API [RFC5653],
specifically the notion of creating an "empty" SECURITY CONTEXT
handle that can then be passed to GSS_Init_sec_context() and
GSS_Accept_sec_context() where they normally expect a NULL handle.
This empty security context handle can then be used to set options
relating to security context token establishment.
In [I-D.williams-williams-kitten-ctx-simple-async] we explore and
extend this design to produce a more usable GSS-API (as well as
support for asynchronous operation).
1.3. Alternative Design
An earlier design was based on an existing, non-standard extension
for carrying security context establishment options in CREDENTIAL
HANDLEs. A notion of CREDENTIAL HANDLE options might still be useful
for options that are really specific to credentials rather than
security context tokens, but for the time being we have no use for
such a thing.
1.4. Future Directions
We're likely to introduce additional mutator functions of empty
contexts, with mutators corresponding to many of the existing input
arguments of GSS_Init_sec_context() and GSS_Accept_sec_context(), as
well as a few additional security context inquiry functions. We're
also likely to then introduce new variants of GSS_Init_sec_context()
and GSS_Accept_sec_context() with all of those input and output
parameters removed that could be set or retrieved with the other new
functions. The only inputs that the new GSS_Init/
Accept_sec_context() must have are: a security context handle (never
NULL), and an input context token, and the only outputs should be the
status indicators and an output token. In fact, we may want to have
just one new function called, perhaps, GSS_Step_sec_context(), with
the role of initiator or acceptor set as a context option.
See [I-D.williams-williams-kitten-ctx-simple-async]. The design for signalling application flag support and empty contexts
is based on the Java Bindings of the GSS-API [RFC5653]. This
document begins introduction of additional context inquiry and
mutation functions, which eventually will also allow for simplified
stepping to replace the GSS_Init/Accept_sec_context() loop.
1.5. Conventions used in this document 1.2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Channel Binding State Extension 2. Channel Binding State Extension
We propose a new return flag for GSS_Init_sec_context() and We propose a new return flag for GSS_Init_sec_context() and
GSS_Accept_sec_context(), as well as a pair of functions for a) GSS_Accept_sec_context(), as well as a pair of functions for a)
creating "empty" security context handles, b) setting req_flags and creating "empty" security context handles, b) requesting flags and
indicating which ret_flags the application understands. We also add indicating which flags the application understands. We also add new
new mechanism attributes describing mechanism capabilities. mechanism attributes describing mechanism capabilities.
C bindings of these extensions are provided along the lines of C bindings of these extensions are provided along the lines of
[RFC2744] and [RFC5587]. [RFC2744] and [RFC5587].
In the future we might move more of the many input (and output) In the future we might move more of the many input (and output)
arguments to GSS_Init_sec_context() and GSS_Accept_sec_context() into arguments to GSS_Init_sec_context() and GSS_Accept_sec_context() into
mutators on empty security context handles. mutators on empty security context handles.
2.1. GSS_Create_sec_context() 2.1. GSS_Create_sec_context()
skipping to change at page 6, line 30 skipping to change at page 5, line 30
o minor_status INTEGER o minor_status INTEGER
Return major status codes: Return major status codes:
o GSS_S_COMPLETE indicates success. o GSS_S_COMPLETE indicates success.
o GSS_S_FAILURE indicates a general failure. o GSS_S_FAILURE indicates a general failure.
This function tells the mechanism (when one is eventually chosen and This function tells the mechanism (when one is eventually chosen and
invoked) that the application requests the given req_flags and invoked) that the application requests the given req_flags and is
undestands the given ret_flags. Initiators can override the prepared to check the flags in the given ret_flags_understood.
req_flags in their GSS_Init_sec_context() call, but if no flags are Mechanisms SHOULD NOT limit flags returned to those in
requested there then the req_flags set on the empty context will be ret_flags_understood, but MAY alter behavior accordingly. Initiators
used. can override the req_flags in their GSS_Init_sec_context() call, but
if no flags are requested there then the req_flags set on the empty
context will be used. GSS_Accept_sec_context() is not required to
perform any action based on req_flags at this time.
NOTE: The abstract GSS-API [RFC2743] uses individual elements -one NOTE: The abstract GSS-API [RFC2743] uses individual elements--one
per-flag- instead of a "FLAGS" type. This is unwieldy, therefore we per-flag--instead of a "FLAGS" type. This is unwieldy, therefore we
introduce an abstract type named "FLAGS" to act as a set of all the introduce an abstract type named "FLAGS" to act as a set of all the
request/return flags defined for the abstract GSS-API. request/return flags defined for the abstract GSS-API.
2.2.1. C-Bindings 2.2.1. C-Bindings
OM_uint32 OM_uint32
gss_set_context_flags(OM_uint32 *minor_status, gss_set_context_flags(OM_uint32 *minor_status,
gss_ctx_id_t context, gss_ctx_id_t context,
uint64_t req_flags, uint64_t req_flags,
uint64_t ret_flags); uint64_t ret_flags_understood);
2.3. Return Flag for Channel Binding State Signalling 2.3. Return Flag for Channel Binding State Signalling
Whenever both the initiator and the acceptor provide matching channel Whenever both the initiator and the acceptor provide matching channel
bindings to GSS_Init_sec_context() and GSS_Accept_sec_context(), bindings to GSS_Init_sec_context() and GSS_Accept_sec_context(),
respectively, then the mechanism SHALL indicate that the context is respectively, then the mechanism SHALL indicate that the context is
channel bound via an output flag, ret_channel_bound_flag, for the channel bound via an output flag, ret_channel_bound_flag, for the
established context. Note that some mechanisms have no way for the established context. Note that some mechanisms have no way for the
acceptor to signal CB success to the initiator, in which case acceptor to signal CB success to the initiator, in which case
GSS_Init_sec_context() MUST NOT output the ret_channel_bound_flag. GSS_Init_sec_context() MUST NOT output the ret_channel_bound_flag.
2.3.1. C-Bindings 2.3.1. C-Bindings
#define GSS_C_CHANNEL_BOUND_FLAG 2048 /* 0x00000800 */ #define GSS_C_CHANNEL_BOUND_FLAG 2048 /* 0x00000800 */
2.4. New Mechanism Attributes 2.4. New Mechanism Attributes
o We add a new mechanism attribute, GSS_C_MA_CBINDING_CONFIRM, to o We add a new mechanism attribute, GSS_C_MA_CBINDING_CONFIRM, to
indicate that the initiator can and always does learn whether the indicate that the initiator can and always does learn whether the
acceptor application supplied channel bindings. Mechanisms acceptor application supplied channel bindings (assuming mutual
advertising this attribute MUST always indicate acceptor channel auth has been requested). Mechanisms advertising this attribute
bound state to the initiator. MUST always indicate acceptor channel bound state to the
initiator.
o We add a new mechanism attribute, GSS_C_MA_CBINDING_MAY_CONFIRM, o We add a new mechanism attribute, GSS_C_MA_CBINDING_MAY_CONFIRM,
to indicate that the initiator may learn whether the acceptor to indicate that the initiator may learn whether the acceptor
application supplied channel bindings, but only when the acceptor application supplied channel bindings (assuming mutual auth has
implementation of the mechanism has been suitably updated. been requested), but only when the acceptor implementation of the
Mechanisms MUST advertise this attribute when the local initiator mechanism has been suitably updated. Mechanisms MUST advertise
functionality for acceptor channel bound state indication exists this attribute when the local initiator functionality for acceptor
but the acceptor may lack the same functionality (because, for channel bound state indication exists but the acceptor may lack
example, the mechanism predates this specification). the same functionality (because, for example, the mechanism
predates this specification).
OID assignments TBD. OID assignments TBD.
2.5. Request Flag for Acceptor Confirmation of Channel Binding 2.5. Request Flag for Acceptor Confirmation of Channel Binding
We add a new request flag for GSS_Init_sec_context(), We add a new request flag for GSS_Init_sec_context(),
req_cb_confirmation_flag, to be used by initiators that insist on req_cb_confirmation_flag, to be used by initiators that insist on
acceptors providing channel bindings. This flag is only of use to acceptors providing channel bindings. This flag is only of use to
mechanism-negotiation pseudo-mechanisms (e.g., SPNEGO [RFC4178]): if mechanism-negotiation pseudo-mechanisms (e.g., SPNEGO [RFC4178]): if
set the pseudo-mechanism MUST NOT negotiate any mechanisms that lack set, the pseudo-mechanism MUST NOT negotiate any mechanisms that lack
the GSS_C_MA_CBINDING_CONFIRM or GSS_C_MA_CBINDING_MAY_CONFIRM both the GSS_C_MA_CBINDING_CONFIRM and GSS_C_MA_CBINDING_MAY_CONFIRM
mechanism attributes, and SHOULD NOT negotiate mechanisms that lack mechanism attributes, and SHOULD NOT negotiate mechanisms that lack
the GSS_C_MA_CBINDING_CONFIRM mechanism attribute (except if allowed the GSS_C_MA_CBINDING_CONFIRM mechanism attribute (except if allowed
by local configuration). by local configuration).
2.5.1. C-Bindings 2.5.1. C-Bindings
Because GSS_C_CHANNEL_BOUND_FLAG is a return flag only, and this flag Because GSS_C_CHANNEL_BOUND_FLAG is a return flag only, and this flag
is a request flag only, and to save on precious flag bits, we use the is a request flag only, and to save on precious flag bits, we use the
same flag bit assignment for both flags: same flag bit assignment for both flags:
#define GSS_C_CB_CONFIRM_FLAG 2048 /* 0x00000800 */ #define GSS_C_CB_CONFIRM_FLAG 2048 /* 0x00000800 */
2.6. GSS_Delete_sec_context() Behavior When Applied to Empty Security 2.6. Handling Empty Contexts in Other GSS-API Functions
Contexts
GSS_Init_sec_context() and GSS_Accept_sec_context() operate on empty
security contexts as specified above (i.e., examining flags).
All other GSS-API functions MUST treat empty contexts as they would
GSS_C_NO_CONTEXT as well. For most functions, this will result in
returning GSS status code GSS_S_NO_CONTEXT.
GSS_Delete_sec_context() MUST NOT output a context deletion token GSS_Delete_sec_context() MUST NOT output a context deletion token
when applied to empty security contexts. when applied to empty security contexts.
3. Modified Channel Binding Semantics 3. Modified Channel Binding Semantics
The channel binding semantics of the base GSS-API are modified as The channel binding semantics of the base GSS-API are modified as
follows: follows:
o Whenever both, the initiator and acceptor shall have provided o Whenever both the initiator and acceptor have provided
input_channel_bindings to GSS_Init/Accept_sec_context() and the input_channel_bindings to GSS_Init/Accept_sec_context() and the
channel bindings do not match, then the mechanism MUST fail to channel bindings do not match, then the mechanism MUST fail to
establish a security context token. This is a restatement of an establish a security context token. (This is a restatement of an
existing requirement in the base specification, restated for the existing requirement in the base specification.)
reader's convenience.
o Whenever the acceptor application shall have a) provided channel o Whenever the acceptor application has a) provided channel bindings
bindings to GSS_Accept_sec_context(), and b) not indicated support to GSS_Accept_sec_context(), and b) not indicated support for the
for the ret_channel_bound_flag flag, then the mechanism MUST fail ret_channel_bound_flag flag, then the mechanism MUST fail to
to establish a security context if the initiator did not provide establish a security context if the initiator did not provide
channel bindings data. This requirement is critical for security channel bindings data. This requirement is critical for security
purposes, to make applications predating this document secure, and purposes, to make applications predating this document secure, and
this requirement reflects actual implementations as deployed. this requirement reflects actual implementations as deployed.
o Whenever the initiator application shall have a) provided channel o Whenever the initiator application has a) provided channel
bindings to GSS_Init_sec_context(), and b) not indicated support bindings to GSS_Init_sec_context(), and b) not indicated support
for the ret_channel_bound_flag flag, then the mechanism SHOULD NOT for the ret_channel_bound_flag flag, then the mechanism MUST NOT
fail to establish a security context just because the acceptor fail to establish a security context just because the acceptor
failed to provide channel bindings data. This recommendation is failed to provide channel bindings data. This requirement is for
for interoperability purposes, and reflects actual implementations interoperability purposes, and reflects actual implementations
that have been deployed. It is possible that not all security that have been deployed.
mechanism protocols can implement this requirement easily.
o Whenever the application shall have a) provided channel bindings o Whenever the application has a) provided channel bindings to
to GSS_Init_sec_context() or GSS_Accept_sec_context(), and b) GSS_Init_sec_context() or GSS_Accept_sec_context(), and b)
indicated support for the ret_channel_bound_flag flag, then the indicated support for the ret_channel_bound_flag flag, then the
mechanism MUST NOT fail to establish a security context just mechanism MUST NOT fail to establish a security context just
because the peer did not provide channel bindings data. The because the peer did not provide channel bindings data. The
mechanism MUST output the ret_channel_bound_flag if both peers mechanism MUST output the ret_channel_bound_flag if both peers
provided the same input_channel_bindings to GSS_Init_sec_context() provided the same input_channel_bindings to GSS_Init_sec_context()
and GSS_Accept_sec_context. The mechanism MUST NOT output the and GSS_Accept_sec_context. The mechanism MUST NOT output the
ret_channel_bound_flag if either (or both) peer did not provide ret_channel_bound_flag if either (or both) peer did not provide
input_channel_bindings to GSS_Init/Accept_sec_context(). This input_channel_bindings to GSS_Init/Accept_sec_context(). This
requirement restores the original base GSS-API specified behavior, requirement restores the original base GSS-API specified behavior,
with the addition of the ret_channel_bound_flag flag. with the addition of the ret_channel_bound_flag flag.
skipping to change at page 9, line 35 skipping to change at page 8, line 41
for Mechanism gsscma Codes" registry established by RFC5587 for Mechanism gsscma Codes" registry established by RFC5587
[RFC5587]. See Section 2.4. [RFC5587]. See Section 2.4.
6. References 6. References
6.1. Normative References 6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC2743] Linn, J., "Generic Security Service Application Program [RFC2743] Linn, J., "Generic Security Service Application Program
Interface Version 2, Update 1", RFC 2743, Interface Version 2, Update 1", RFC 2743,
DOI 10.17487/RFC2743, January 2000, DOI 10.17487/RFC2743, January 2000,
<http://www.rfc-editor.org/info/rfc2743>. <https://www.rfc-editor.org/info/rfc2743>.
[RFC2744] Wray, J., "Generic Security Service API Version 2 : [RFC2744] Wray, J., "Generic Security Service API Version 2 :
C-bindings", RFC 2744, DOI 10.17487/RFC2744, January 2000, C-bindings", RFC 2744, DOI 10.17487/RFC2744, January 2000,
<http://www.rfc-editor.org/info/rfc2744>. <https://www.rfc-editor.org/info/rfc2744>.
[RFC5056] Williams, N., "On the Use of Channel Bindings to Secure [RFC5056] Williams, N., "On the Use of Channel Bindings to Secure
Channels", RFC 5056, DOI 10.17487/RFC5056, November 2007, Channels", RFC 5056, DOI 10.17487/RFC5056, November 2007,
<http://www.rfc-editor.org/info/rfc5056>. <https://www.rfc-editor.org/info/rfc5056>.
[RFC5587] Williams, N., "Extended Generic Security Service Mechanism [RFC5587] Williams, N., "Extended Generic Security Service Mechanism
Inquiry APIs", RFC 5587, DOI 10.17487/RFC5587, July 2009, Inquiry APIs", RFC 5587, DOI 10.17487/RFC5587, July 2009,
<http://www.rfc-editor.org/info/rfc5587>. <https://www.rfc-editor.org/info/rfc5587>.
6.2. Informative References 6.2. Informative References
[RFC4121] Zhu, L., Jaganathan, K., and S. Hartman, "The Kerberos
Version 5 Generic Security Service Application Program
Interface (GSS-API) Mechanism: Version 2", RFC 4121,
DOI 10.17487/RFC4121, July 2005,
<http://www.rfc-editor.org/info/rfc4121>.
[RFC4178] Zhu, L., Leach, P., Jaganathan, K., and W. Ingersoll, "The [RFC4178] Zhu, L., Leach, P., Jaganathan, K., and W. Ingersoll, "The
Simple and Protected Generic Security Service Application Simple and Protected Generic Security Service Application
Program Interface (GSS-API) Negotiation Mechanism", Program Interface (GSS-API) Negotiation Mechanism",
RFC 4178, DOI 10.17487/RFC4178, October 2005, RFC 4178, DOI 10.17487/RFC4178, October 2005,
<http://www.rfc-editor.org/info/rfc4178>. <https://www.rfc-editor.org/info/rfc4178>.
[RFC5653] Upadhyay, M. and S. Malkani, "Generic Security Service API [RFC5653] Upadhyay, M. and S. Malkani, "Generic Security Service API
Version 2: Java Bindings Update", RFC 5653, Version 2: Java Bindings Update", RFC 5653,
DOI 10.17487/RFC5653, August 2009, DOI 10.17487/RFC5653, August 2009,
<http://www.rfc-editor.org/info/rfc5653>. <https://www.rfc-editor.org/info/rfc5653>.
[I-D.williams-williams-kitten-ctx-simple-async] Authors' Addresses
Williams, N., "Simplified and Asynchronous Security
Context Interfaces for the Generic Security Services
Application Programming Interface", draft-williams-
williams-kitten-ctx-simple-async-00 (work in progress),
February 2013.
Author's Address Robbie Harwood
Red Hat, Inc.
Email: rharwood@redhat.com
Nicolas Williams Nicolas Williams
Cryptonector, LLC Cryptonector, LLC
Email: nico@cryptonector.com Email: nico@cryptonector.com
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