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.Dd January 26, 2010
.Dt GSS_UNWRAP 3 PRM
.Os
.Sh NAME
.Nm gss_unwrap ,
.Nm gss_unseal
.Nd Convert a message previously protected by
.Xr gss_wrap 3
back to a usable form
.\" This next command is for sections 2 and 3 only.
.\" .Sh LIBRARY
.Sh SYNOPSIS
.In "gssapi/gssapi.h"
.Ft OM_uint32
.Fo gss_unwrap
.Fa "OM_uint32 *minor_status"
.Fa "const gss_ctx_id_t context_handle"
.Fa "const gss_buffer_t input_message_buffer"
.Fa "gss_buffer_t output_message_buffer"
.Fa "int *conf_state"
.Fa "gss_qop_t *qop_state"
.Fc
.Ft OM_uint32
.Fo gss_unseal
.Fa "OM_uint32 *minor_status"
.Fa "gss_ctx_id_t context_handle"
.Fa "gss_buffer_t input_message_buffer"
.Fa "gss_buffer_t output_message_buffer"
.Fa "int *conf_state"
.Fa "gss_qop_t *qop_state"
.Fc
.Sh DESCRIPTION
Converts a message previously protected by
.Xr gss_wrap 3
back to a usable form,
verifying the embedded MIC.
The
.Dv conf_state
parameter indicates whether the message was encrypted;
the
.Dv qop_state
parameter indicates the strength of protection that was used to provide the
confidentiality and integrity services.
.Pp
Since some application-level protocols may wish to use tokens emitted
by
.Xr gss_wrap 3
to provide "secure framing",
implementations must support the wrapping and unwrapping of
zero-length messages.
.Pp
The
.Fn gss_unseal
routine is an obsolete variant of
.Fn gss_unwrap .
It is
provided for backwards
compatibility with applications using the GSS-API V1 interface.
A distinct entrypoint (as opposed to #define) is provided,
both to allow GSS-API V1 applications to link
and to retain the slight parameter type differences between the
obsolete versions of this routine and its current form.
.Sh PARAMETERS
.Bl -tag -width ".It output_message_buffer"
.It minor_status
Mechanism specific status code.
.It context_handle
Identifies the context on which the message arrived.
.It input_message_buffer
Protected message.
.It output_message_buffer
Buffer to receive unwrapped message.
Storage associated with this buffer must
be freed by the application after use
with a call to
.Xr gss_release_buffer 3 .
.It conf_state
.Bl -tag -width "Non-zero"
.It Non-zero
Confidentiality and integrity protection were used.
.It Zero
Integrity service only was used.
.El
.Pp
Specify NULL if not required.
.It qop_state
Quality of protection provided. Specify NULL if not required.
.El
.Sh RETURN VALUES
.Bl -tag -width ".It GSS_S_CONTEXT_EXPIRED"
.It GSS_S_COMPLETE
Successful completion.
.It GSS_S_DEFECTIVE_TOKEN
The token failed consistency checks.
.It GSS_S_BAD_SIG
The MIC was incorrect
.It GSS_S_DUPLICATE_TOKEN
The token was valid, and contained a correct
MIC for the message, but it had already been
processed.
.It GSS_S_OLD_TOKEN
The token was valid, and contained a correct MIC
for the message, but it is too old to check for
duplication.
.It GSS_S_UNSEQ_TOKEN
The token was valid, and contained a correct MIC
for the message, but has been verified out of
sequence; a later token has already been
received.
.It GSS_S_GAP_TOKEN
The token was valid, and contained a correct MIC
for the message, but has been verified out of
sequence; an earlier expected token has not yet
been received.
.It GSS_S_CONTEXT_EXPIRED
The context has already expired.
.It GSS_S_NO_CONTEXT
The context_handle parameter did not identify a valid context.
.El
.Sh SEE ALSO
.Xr gss_wrap 3 ,
.Xr gss_release_buffer 3
.Sh STANDARDS
.Bl -tag -width ".It RFC 2743"
.It RFC 2743
Generic Security Service Application Program Interface Version 2, Update 1
.It RFC 2744
Generic Security Service API Version 2 : C-bindings
.El
.Sh HISTORY
The
.Nm
function first appeared in
.Fx 7.0 .
.Sh AUTHORS
John Wray, Iris Associates
.Sh COPYRIGHT
Copyright (C) The Internet Society (2000). All Rights Reserved.
.Pp
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
.Pp
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
.Pp
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
