librpc: add dcerpc_get_auth_{type,level,context_id}() helper functions

[sfrench/samba-autobuild/.git] / librpc / rpc / dcerpc_util.c

diff --git a/librpc/rpc/dcerpc_util.c b/librpc/rpc/dcerpc_util.c
index 6cd3e38a75a0dd1fb08488db0c055bcd345cb2db..e0479c2f36b1aea81a1536937f4f726080dab69e 100644 (file)
--- a/librpc/rpc/dcerpc_util.c
+++ b/librpc/rpc/dcerpc_util.c
@@ -73,6 +73,93 @@ uint8_t dcerpc_get_endian_flag(DATA_BLOB *blob)
        return blob->data[DCERPC_DREP_OFFSET];
 }
 
+static uint16_t dcerpc_get_auth_context_offset(const DATA_BLOB *blob)
+{
+       uint16_t frag_len = dcerpc_get_frag_length(blob);
+       uint16_t auth_len = dcerpc_get_auth_length(blob);
+       uint16_t min_offset;
+       uint16_t offset;
+
+       if (auth_len == 0) {
+               return 0;
+       }
+
+       if (frag_len > blob->length) {
+               return 0;
+       }
+
+       if (auth_len > frag_len) {
+               return 0;
+       }
+
+       min_offset = DCERPC_NCACN_PAYLOAD_OFFSET + DCERPC_AUTH_TRAILER_LENGTH;
+       offset = frag_len - auth_len;
+       if (offset < min_offset) {
+               return 0;
+       }
+       offset -= DCERPC_AUTH_TRAILER_LENGTH;
+
+       return offset;
+}
+
+uint8_t dcerpc_get_auth_type(const DATA_BLOB *blob)
+{
+       uint16_t offset;
+
+       offset = dcerpc_get_auth_context_offset(blob);
+       if (offset == 0) {
+               return 0;
+       }
+
+       /*
+        * auth_typw is in the 1st byte
+        * of the auth trailer
+        */
+       offset += 0;
+
+       return blob->data[offset];
+}
+
+uint8_t dcerpc_get_auth_level(const DATA_BLOB *blob)
+{
+       uint16_t offset;
+
+       offset = dcerpc_get_auth_context_offset(blob);
+       if (offset == 0) {
+               return 0;
+       }
+
+       /*
+        * auth_level is in 2nd byte
+        * of the auth trailer
+        */
+       offset += 1;
+
+       return blob->data[offset];
+}
+
+uint32_t dcerpc_get_auth_context_id(const DATA_BLOB *blob)
+{
+       uint16_t offset;
+
+       offset = dcerpc_get_auth_context_offset(blob);
+       if (offset == 0) {
+               return 0;
+       }
+
+       /*
+        * auth_context_id is in the last 4 byte
+        * of the auth trailer
+        */
+       offset += 4;
+
+       if (CVAL(blob->data,DCERPC_DREP_OFFSET) & DCERPC_DREP_LE) {
+               return IVAL(blob->data, offset);
+       } else {
+               return RIVAL(blob->data, offset);
+       }
+}
+
 /**
 * @brief Decodes a ncacn_packet
 *