net: rework the NPN patch.

net/third_party/nss/ssl/ssl3ext.c

 /*
  * SSL3 Protocol
  *
  * ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
  * The contents of this file are subject to the Mozilla Public License Version
  * 1.1 (the "License"); you may not use this file except in compliance with
  * the License. You may obtain a copy of the License at
  * http://www.mozilla.org/MPL/
@@ skipping 536 matching lines @@
 
 /* handle an incoming Next Protocol Negotiation extension. */
 SECStatus
 ssl3_ServerHandleNextProtoNegoXtn(sslSocket * ss, PRUint16 ex_type, SECItem *data)
 {
     if (data->len != 0) {
         /* Clients MUST send an empty NPN extension, if any. */
         return SECFailure;
     }
 
-    ss->ssl3.hs.nextProtoNego = PR_TRUE;
     return SECSuccess;
 }
 
 /* ssl3_ValidateNextProtoNego checks that the given block of data is valid: none
- * of the length may be 0 and the sum of the lengths must equal the length of
+ * of the lengths may be 0 and the sum of the lengths must equal the length of
  * the block. */
 SECStatus
 ssl3_ValidateNextProtoNego(const unsigned char* data, unsigned short length)
 {
     unsigned int offset = 0;
 
     while (offset < length) {
         if (data[offset] == 0) {
+            PORT_SetError(SSL_ERROR_NEXT_PROTOCOL_DATA_INVALID);
             return SECFailure;
         }
         offset += (unsigned int)data[offset] + 1;
     }
 
-    if (offset > length)
+    if (offset > length) {
+        PORT_SetError(SSL_ERROR_NEXT_PROTOCOL_DATA_INVALID);
         return SECFailure;
+    }
 
     return SECSuccess;
 }
 
 SECStatus
 ssl3_ClientHandleNextProtoNegoXtn(sslSocket *ss, PRUint16 ex_type,
-                                 SECItem *data)
+                                  SECItem *data)
 {
-    unsigned int i, j;
     SECStatus rv;
-    unsigned char *result;
-
-    if (data->len == 0) {
-        /* The server supports the extension, but doesn't have any
-         * protocols configured. In this case we request our favoured
-         * protocol. */
-        goto pick_first;
-    }
+    unsigned char result[255];
+    unsigned int result_len;
 
     rv = ssl3_ValidateNextProtoNego(data->data, data->len);
     if (rv != SECSuccess)
         return rv;
 
-    /* For each protocol in server preference order, see if we support it. */
-    for (i = 0; i < data->len; ) {
-        for (j = 0; j < ss->opt.nextProtoNego.len; ) {
-            if (data->data[i] == ss->opt.nextProtoNego.data[j] &&
-                memcmp(&data->data[i+1], &ss->opt.nextProtoNego.data[j+1],
-                       data->data[i]) == 0) {
-                /* We found a match */
-                ss->ssl3.nextProtoState = SSL_NEXT_PROTO_NEGOTIATED;
-                result = &data->data[i];
-                goto found;
-            }
-            j += (unsigned int)ss->opt.nextProtoNego.data[j] + 1;
-        }
+    rv = ss->nextProtoCallback(ss->nextProtoArg, ss->fd,
+                               data->data, data->len,
+                               result, &result_len);
+    if (rv != SECSuccess)
+        return rv;
+    // If the callback wrote more than allowed to |result| it has corrupted our
+    // stack.
+    PORT_Assert(result_len <= sizeof(result));
 
-        i += (unsigned int)data->data[i] + 1;
-    }
-
-  pick_first:
-    ss->ssl3.nextProtoState = SSL_NEXT_PROTO_NO_OVERLAP;
-    result = ss->opt.nextProtoNego.data;
-
-  found:
     if (ss->ssl3.nextProto.data)
         PORT_Free(ss->ssl3.nextProto.data);
-    ss->ssl3.nextProto.data = PORT_Alloc(result[0]);
-    PORT_Memcpy(ss->ssl3.nextProto.data, result + 1, result[0]);
-    ss->ssl3.nextProto.len = result[0];
+    ss->ssl3.nextProto.data = PORT_Alloc(result_len);
+    PORT_Memcpy(ss->ssl3.nextProto.data, result, result_len);
+    ss->ssl3.nextProto.len = result_len;
     return SECSuccess;
 }
 
 PRInt32
 ssl3_ClientSendNextProtoNegoXtn(sslSocket * ss,
                                PRBool      append,
                                PRUint32    maxBytes)
 {
     PRInt32 extension_length;
 
     /* Renegotiations do not send this extension. */
-    if (ss->opt.nextProtoNego.len == 0 || ss->firstHsDone) {
+    if (!ss->nextProtoCallback || ss->firstHsDone) {
         return 0;
     }
 
     extension_length = 4;
 
     if (append && maxBytes >= extension_length) {
         SECStatus rv;
         rv = ssl3_AppendHandshakeNumber(ss, ssl_next_proto_neg_xtn, 2);
         if (rv != SECSuccess)
             goto loser;
@@ skipping 1396 matching lines @@
 
     /* The echoed extension must be empty. */
     if (data->len != 0)
         return SECFailure;
 
     /* Keep track of negotiated extensions. */
     ss->xtnData.negotiated[ss->xtnData.numNegotiated++] = ex_type;
 
     return SECSuccess;
 }