Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
cc [ flag... ] file... -lgss [ library... ] #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);
The gss_unwrap() function converts a message previously protected by gss_wrap(3GSS) 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(3GSS) to provide secure framing, the GSS-API supports the wrapping and unwrapping of zero-length messages.
The parameter descriptions for gss_unwrap() follow:
minor_status
The status code returned by the underlying mechanism.
context_handle
Identifies the context on which the message arrived.
input_message_buffer
The message to be protected.
output_message_buffer
The buffer to receive the unwrapped message. Storage associated with this buffer must be freed by the application after use with a call to gss_release_buffer(3GSS).
conf_state
If the value of conf_state is non-zero, then confidentiality and integrity protection were used. If the value is zero, only integrity service was used. Specify NULL if this parameter is not required.
qop_state
Specifies the quality of protection provided. Specify NULL if this parameter is not required.
gss_unwrap() may return the following status codes:
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.
GSS_S_FAILURE
The underlying mechanism detected an error for which no specific GSS status code is defined. The mechanism-specific status code reported by means of the minor_status parameter details the error condition.
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| MT-Level | Safe |
gss_release_buffer(3GSS), gss_wrap(3GSS), attributes(5)