Update net/third_party/nss to NSS 3.15.4.

net/third_party/nss/patches/tls12backuphash.patch

-Index: net/third_party/nss/ssl/ssl3con.c
-===================================================================
---- net/third_party/nss/ssl/ssl3con.c   (revision 220594)
-+++ net/third_party/nss/ssl/ssl3con.c   (working copy)
-@@ -3933,6 +3933,20 @@
-                ssl_MapLowLevelError(SSL_ERROR_DIGEST_FAILURE);
-                return SECFailure;
-            }
-+
-+           /* A backup SHA-1 hash for a potential client auth signature. */
-+           if (!ss->sec.isServer) {
-+               ss->ssl3.hs.md5 = PK11_CreateDigestContext(SEC_OID_SHA1);
-+               if (ss->ssl3.hs.md5 == NULL) {
-+                   ssl_MapLowLevelError(SSL_ERROR_SHA_DIGEST_FAILURE);
-+                   return SECFailure;
-+               }
-+
-+               if (PK11_DigestBegin(ss->ssl3.hs.md5) != SECSuccess) {
-+                   ssl_MapLowLevelError(SSL_ERROR_SHA_DIGEST_FAILURE);
-+                   return SECFailure;
-+               }
-+           }
-        } else {
-            /* Both ss->ssl3.hs.md5 and ss->ssl3.hs.sha should be NULL or
-             * created successfully. */
-@@ -4043,6 +4057,13 @@
-            ssl_MapLowLevelError(SSL_ERROR_DIGEST_FAILURE);
-            return rv;
-        }
-+       if (ss->ssl3.hs.md5) {
-+           rv = PK11_DigestOp(ss->ssl3.hs.md5, b, l);
-+           if (rv != SECSuccess) {
-+               ssl_MapLowLevelError(SSL_ERROR_SHA_DIGEST_FAILURE);
-+               return rv;
-+           }
-+       }
-     } else {
-        rv = PK11_DigestOp(ss->ssl3.hs.md5, b, l);
-        if (rv != SECSuccess) {
-@@ -4791,6 +4812,30 @@
-     return rv;
- }
- 
-+static SECStatus
-+ssl3_ComputeBackupHandshakeHashes(sslSocket * ss,
-+                                 SSL3Hashes * hashes) /* output goes here. */
-+{
-+    SECStatus rv = SECSuccess;
-+
-+    PORT_Assert( ss->opt.noLocks || ssl_HaveSSL3HandshakeLock(ss) );
-+    PORT_Assert( ss->ssl3.hs.hashType == handshake_hash_single );
-+
-+    rv = PK11_DigestFinal(ss->ssl3.hs.md5, hashes->u.raw, &hashes->len,
-+                         sizeof(hashes->u.raw));
-+    if (rv != SECSuccess) {
-+       ssl_MapLowLevelError(SSL_ERROR_SHA_DIGEST_FAILURE);
-+       rv = SECFailure;
-+       goto loser;
-+    }
-+    hashes->hashAlg = SEC_OID_SHA1;
-+
-+loser:
-+    PK11_DestroyContext(ss->ssl3.hs.md5, PR_TRUE);
-+    ss->ssl3.hs.md5 = NULL;
-+    return rv;
-+}
-+
- /*
-  * SSL 2 based implementations pass in the initial outbound buffer
-  * so that the handshake hash can contain the included information.
-@@ -6044,7 +6089,17 @@
-                SSL_GETPID(), ss->fd));
- 
-     ssl_GetSpecReadLock(ss);
--    rv = ssl3_ComputeHandshakeHashes(ss, ss->ssl3.pwSpec, &hashes, 0);
-+    /* In TLS 1.2, ssl3_ComputeHandshakeHashes always uses the handshake hash
-+     * function (SHA-256). If the server or the client does not support SHA-256
-+     * as a signature hash, we can either maintain a backup SHA-1 handshake
-+     * hash or buffer all handshake messages.
-+     */
-+    if (ss->ssl3.hs.hashType == handshake_hash_single && ss->ssl3.hs.md5) {
-+       rv = ssl3_ComputeBackupHandshakeHashes(ss, &hashes);
-+       PORT_Assert(ss->ssl3.hs.md5 == NULL);
-+    } else {
-+       rv = ssl3_ComputeHandshakeHashes(ss, ss->ssl3.pwSpec, &hashes, 0);
-+    }
-     ssl_ReleaseSpecReadLock(ss);
-     if (rv != SECSuccess) {
-        goto done;      /* err code was set by ssl3_ComputeHandshakeHashes */
-@@ -6098,11 +6153,6 @@
-        if (rv != SECSuccess) {
-            goto done;
-        }
--       /* We always sign using the handshake hash function. It's possible that
--        * a server could support SHA-256 as the handshake hash but not as a
--        * signature hash. In that case we wouldn't be able to do client
--        * certificates with it. The alternative is to buffer all handshake
--        * messages. */
-        sigAndHash.hashAlg = hashes.hashAlg;
- 
-        rv = ssl3_AppendSignatureAndHashAlgorithm(ss, &sigAndHash);
-@@ -6802,6 +6852,70 @@
- }
- 
- 
-+/*
-+ * Returns true if the client authentication key is an RSA or DSA key that
-+ * may be able to sign only SHA-1 hashes.
-+ */
-+static PRBool
-+ssl3_ClientKeyPrefersSHA1(sslSocket *ss)
-+{
-+    SECKEYPublicKey *pubk;
-+    PRBool prefer_sha1 = PR_FALSE;
-+
-+#if defined(NSS_PLATFORM_CLIENT_AUTH) && defined(_WIN32)
-+    /* If the key is in CAPI, assume conservatively that the CAPI service
-+     * provider may be unable to sign SHA-256 hashes.
-+     */
-+    if (ss->ssl3.platformClientKey->dwKeySpec != CERT_NCRYPT_KEY_SPEC) {
-+       /* CAPI only supports RSA and DSA signatures, so we don't need to
-+        * check the key type. */
-+       return PR_TRUE;
-+    }
-+#endif  /* NSS_PLATFORM_CLIENT_AUTH && _WIN32 */
-+
-+    /* If the key is a 1024-bit RSA or DSA key, assume conservatively that
-+     * it may be unable to sign SHA-256 hashes. This is the case for older
-+     * Estonian ID cards that have 1024-bit RSA keys. In FIPS 186-2 and
-+     * older, DSA key size is at most 1024 bits and the hash function must
-+     * be SHA-1.
-+     */
-+    pubk = CERT_ExtractPublicKey(ss->ssl3.clientCertificate);
-+    if (pubk == NULL) {
-+       return PR_FALSE;
-+    }
-+    if (pubk->keyType == rsaKey || pubk->keyType == dsaKey) {
-+       prefer_sha1 = SECKEY_PublicKeyStrength(pubk) <= 128;
-+    }
-+    SECKEY_DestroyPublicKey(pubk);
-+    return prefer_sha1;
-+}
-+
-+/* Destroys the backup handshake hash context if we don't need it. */
-+static void
-+ssl3_DestroyBackupHandshakeHashIfNotNeeded(sslSocket *ss,
-+                                          const SECItem *algorithms)
-+{
-+    PRBool need_backup_hash = PR_FALSE;
-+    unsigned int i;
-+
-+    PORT_Assert(ss->ssl3.hs.md5);
-+    if (ssl3_ClientKeyPrefersSHA1(ss)) {
-+       /* Use SHA-1 if the server supports it. */
-+       for (i = 0; i < algorithms->len; i += 2) {
-+           if (algorithms->data[i] == tls_hash_sha1 &&
-+               (algorithms->data[i+1] == tls_sig_rsa ||
-+                algorithms->data[i+1] == tls_sig_dsa)) {
-+               need_backup_hash = PR_TRUE;
-+               break;
-+           }
-+       }
-+    }
-+    if (!need_backup_hash) {
-+       PK11_DestroyContext(ss->ssl3.hs.md5, PR_TRUE);
-+       ss->ssl3.hs.md5 = NULL;
-+    }
-+}
-+
- typedef struct dnameNode {
-     struct dnameNode *next;
-     SECItem           name;
-@@ -6994,6 +7108,9 @@
-                }
-                goto send_no_certificate;
-            }
-+           if (isTLS12) {
-+               ssl3_DestroyBackupHandshakeHashIfNotNeeded(ss, &algorithms);
-+           }
-            break;  /* not an error */
-        }
- #endif   /* NSS_PLATFORM_CLIENT_AUTH */
-@@ -7029,6 +7146,9 @@
-            }
-            goto send_no_certificate;
-        }
-+       if (isTLS12) {
-+           ssl3_DestroyBackupHandshakeHashIfNotNeeded(ss, &algorithms);
-+       }
-        break;  /* not an error */
- 
-     case SECFailure:
-@@ -7227,6 +7347,13 @@
-                     (ss->ssl3.platformClientKey ||
-                     ss->ssl3.clientPrivateKey != NULL);
- 
-+    if (!sendClientCert &&
-+       ss->ssl3.hs.hashType == handshake_hash_single && ss->ssl3.hs.md5) {
-+       /* Don't need the backup handshake hash. */
-+       PK11_DestroyContext(ss->ssl3.hs.md5, PR_TRUE);
-+       ss->ssl3.hs.md5 = NULL;
-+    }
-+
-     /* We must wait for the server's certificate to be authenticated before
-      * sending the client certificate in order to disclosing the client
-      * certificate to an attacker that does not have a valid cert for the
-Index: net/third_party/nss/ssl/sslimpl.h
-===================================================================
---- net/third_party/nss/ssl/sslimpl.h   (revision 220594)
-+++ net/third_party/nss/ssl/sslimpl.h   (working copy)
-@@ -838,6 +838,9 @@
-      * SSL 3.0 - TLS 1.1 use both |md5| and |sha|. |md5| is used for MD5 and
-      * |sha| for SHA-1.
-      * TLS 1.2 and later use only |sha|, for SHA-256. */
-+    /* NOTE: On the client side, TLS 1.2 and later use |md5| as a backup
-+     * handshake hash for generating client auth signatures. Confusingly, the
-+     * backup hash function is SHA-1. */
-     PK11Context *         md5;
-     PK11Context *         sha;
-