Changeset 1275 for pjproject/trunk/pjnath/src/pjnath/stun_auth.c

Timestamp:

May 15, 2007 10:42:56 AM (17 years ago)

Author:

bennylp

Message:

Fixed several STUN bugs: USERNAME, REALM etc are not allowed in the response, retransmission timer calculation bug, etc.

File:

• pjproject/trunk/pjnath/src/pjnath/stun_auth.c (modified) (6 diffs)

pjproject/trunk/pjnath/src/pjnath/stun_auth.c

@@ -105 +105 @@
 
 
-/* Verify credential */
-PJ_DEF(pj_status_t) pj_stun_verify_credential( const pj_uint8_t *pkt,
-                                               unsigned pkt_len,
-                                               const pj_stun_msg *msg,
-                                               pj_stun_auth_cred *cred,
-                                               pj_pool_t *pool,
-                                               pj_stun_msg **p_response)
+/* Verify credential in the request */
+PJ_DEF(pj_status_t) pj_stun_authenticate_request(const pj_uint8_t *pkt,
+                                                 unsigned pkt_len,
+                                                 const pj_stun_msg *msg,
+                                                 pj_stun_auth_cred *cred,
+                                                 pj_pool_t *pool,
+                                                 pj_stun_msg **p_response)
 {
     pj_str_t realm, nonce, password;
@@ -122 +122 @@
     pj_hmac_sha1_context ctx;
     pj_uint8_t digest[PJ_SHA1_DIGEST_SIZE];
-    pj_uint8_t md5_digest[16];
     pj_str_t key;
     pj_status_t status;
@@ -225 +224 @@
 
         /* NONCE must be present. */
-        if (anonce == NULL) {
+        if (anonce == NULL && nonce.slen) {
             if (p_response) {
                 create_challenge(pool, msg, PJ_STUN_SC_MISSING_NONCE, 
@@ -320 +319 @@
     }
 
-    /* Determine which key to use */
-    if (realm.slen) {
-        pj_stun_calc_md5_key(md5_digest, &realm, &auser->value, &password);
-        key.ptr = (char*)md5_digest;
-        key.slen = 16;
-    } else {
-        key = password;
-    }
+    /* Calculate key */
+    pj_stun_create_key(pool, &key, &realm, &auser->value, &password);
 
     /* Now calculate HMAC of the message, adding zero padding if necessary
@@ -334 +327 @@
     pj_hmac_sha1_init(&ctx, (pj_uint8_t*)key.ptr, key.slen);
     pj_hmac_sha1_update(&ctx, pkt, amsgi_pos);
-    if (amsgi_pos & 0x3F) {
+    if (amsgi_pos & 63) {
         pj_uint8_t zeroes[64];
         pj_bzero(zeroes, sizeof(zeroes));
-        pj_hmac_sha1_update(&ctx, zeroes, 64-(amsgi_pos & 0x3F));
+        pj_hmac_sha1_update(&ctx, zeroes, 64-(amsgi_pos & 63));
     }
     pj_hmac_sha1_final(&ctx, digest);
@@ -356 +349 @@
 
 
+/* Authenticate MESSAGE-INTEGRITY in the response */
+PJ_DEF(pj_status_t) pj_stun_authenticate_response(const pj_uint8_t *pkt,
+                                                  unsigned pkt_len,
+                                                  const pj_stun_msg *msg,
+                                                  const pj_str_t *key)
+{
+    const pj_stun_msgint_attr *amsgi;
+    unsigned amsgi_pos;
+    pj_hmac_sha1_context ctx;
+    pj_uint8_t digest[PJ_SHA1_DIGEST_SIZE];
+
+    PJ_ASSERT_RETURN(pkt && pkt_len && msg && key, PJ_EINVAL);
+
+    /* First check that MESSAGE-INTEGRITY is present */
+    amsgi = (const pj_stun_msgint_attr*)
+            pj_stun_msg_find_attr(msg, PJ_STUN_ATTR_MESSAGE_INTEGRITY, 0);
+    if (amsgi == NULL) {
+        return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_INTEGRITY_CHECK_FAILURE);
+    }
+
+
+    /* Check that message length is valid */
+    if (msg->hdr.length < 24) {
+        return PJNATH_EINSTUNMSGLEN;
+    }
+
+    /* Get the position of MESSAGE-INTEGRITY in the packet */
+    amsgi_pos = 20+msg->hdr.length-24;
+    if (GET_VAL16(pkt, amsgi_pos) == PJ_STUN_ATTR_MESSAGE_INTEGRITY) {
+        /* Found MESSAGE-INTEGRITY as the last attribute */
+    } else {
+        amsgi_pos = 0;
+    }
+    
+    if (amsgi_pos==0) {
+        /* Check that message length is valid */
+        if (msg->hdr.length < 32) {
+            return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_INTEGRITY_CHECK_FAILURE);
+        }
+
+        amsgi_pos = 20+msg->hdr.length-8-24;
+        if (GET_VAL16(pkt, amsgi_pos) == PJ_STUN_ATTR_MESSAGE_INTEGRITY) {
+            /* Found MESSAGE-INTEGRITY before FINGERPRINT */
+        } else {
+            amsgi_pos = 0;
+        }
+    }
+
+    if (amsgi_pos==0) {
+        return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_INTEGRITY_CHECK_FAILURE);
+    }
+
+    /* Now calculate HMAC of the message, adding zero padding if necessary
+     * to make the input 64 bytes aligned.
+     */
+    pj_hmac_sha1_init(&ctx, (pj_uint8_t*)key->ptr, key->slen);
+    pj_hmac_sha1_update(&ctx, pkt, amsgi_pos);
+    if (amsgi_pos & 0x3F) {
+        pj_uint8_t zeroes[64];
+        pj_bzero(zeroes, sizeof(zeroes));
+        pj_hmac_sha1_update(&ctx, zeroes, 64-(amsgi_pos & 0x3F));
+    }
+    pj_hmac_sha1_final(&ctx, digest);
+
+    /* Compare HMACs */
+    if (pj_memcmp(amsgi->hmac, digest, 20)) {
+        /* HMAC value mismatch */
+        return PJ_STATUS_FROM_STUN_CODE(PJ_STUN_SC_INTEGRITY_CHECK_FAILURE);
+    }
+
+    /* Everything looks okay! */
+    return PJ_SUCCESS;
+}
+