Strings and Similar Data in GSS-API

Because GSS-API handles all data in internal formats, strings must be converted to a GSS-API format before being passed to GSS-API functions. GSS-API handles strings with the gss_buffer_desc structure:

typedef struct gss_buffer_desc_struct {
     size_t     length;
     void       *value;
}  gss_buffer_desc *gss_buffer_t;

gss_buffer_t is a pointer to such a structure. Strings must be put into a gss_buffer_desc structure before being passed to functions that use them. In the following example, a generic GSS-API function applies protection to a message before sending that message.

Example 4–1 Using Strings in GSS-API

char *message_string;
gss_buffer_desc input_msg_buffer;

input_msg_buffer.value = message_string;
input_msg_buffer.length = strlen(input_msg_buffer.value) + 1;

gss_generic_function(arg1, &input_msg_buffer, arg2...);

gss_release_buffer(input_msg_buffer);

Note that input_msg_buffer must be deallocated with gss_release_buffer() when you are finished with input_msg_buffer.

The gss_buffer_desc object is not just for character strings. For example, tokens are manipulated as gss_buffer_desc objects. See GSS-API Tokens for more information.