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:
gss_release_buffer(3GSS), gss_wrap(3GSS), attributes(5)
Solaris Security for Developers Guide