GSS_UNWRAP(3)

NAME
gss_unwrap, gss_unseal - Convert a message previously protected by gss_wrap(3) back to a usable form

SYNOPSIS
#include <gssapi/gssapi.h>
OM_uint32
gss_unwrap(OM_uint32 *minor_status, const gss_ctx_id_t context_handle, const gss_buffer_t input_message_buffer, gss_buffer_t output_message_buffer, int *conf_state, gss_qop_t *qop_state);
OM_uint32
gss_unseal(OM_uint32 *minor_status, gss_ctx_id_t context_handle, gss_buffer_t input_message_buffer, gss_buffer_t output_message_buffer, int *conf_state, gss_qop_t *qop_state);

DESCRIPTION
Converts a message previously protected by gss_wrap(3) back to a usable form, verifying the embedded MIC. The conf_state parameter indicates whether the message was encrypted; the qop_state parameter indicates the strength of protection that was used to provide the confidentiality and integrity services.

Since some application-level protocols may wish to use tokens emitted by gss_wrap(3) to provide "secure framing", implementations must support the wrapping and unwrapping of zero-length messages.

The gss_unseal() routine is an obsolete variant of 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.

PARAMETERS

minor_status
    Mechanism specific status code.

context_handle
    Identifies the context on which the message arrived.

input_message_buffer
    Protected message.

output_message_buffer
    Buffer to receive unwrapped message. Storage associated with this buffer must be freed by the application after use use with a call to gss_release_buffer(3).

conf_state

    Non-zero
        Confidentiality and integrity protection were used.

    Zero
        Integrity service only was used.

    Specify NULL if not required.

qop_state
    Quality of protection provided. Specify NULL if not required.

RETURN VALUES

GSS_S_COMPLETE
    Successful completion.

GSS_S_DEFECTIVE_TOKEN
    The token failed consistency checks.

GSS_S_BAD_SIG
    The MIC was incorrect

GSS_S_DUPLICATE_TOKEN
    The token was valid, and contained a correct MIC for the message, but it had already been processed.

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.

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.

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.

GSS_S_CONTEXT_EXPIRED
    The context has already expired.

GSS_S_NO_CONTEXT
    The context_handle parameter did not identify a valid context.

SEE ALSO
gss_wrap(3), gss_release_buffer(3)

STANDARDS

RFC 2743
    Generic Security Service Application Program Interface Version 2, Update 1

RFC 2744
    Generic Security Service API Version 2 : C-bindings

HISTORY
The gss_unwrap function first appeared in FreeBSD 7.0.

AUTHORS
John Wray, Iris Associates

COPYRIGHT
Copyright (C) The Internet Society (2000). All Rights Reserved.

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