net: rework the NPN patch.

This change moves the protocol selection logic out of NSS and into Chromium
code. This allows some things to be a little cleaner (no more wire-encoded NPN
strings) and also allows for some tricks that we have been considering for
SPDY+WebSockets.

As a consequence of this change, next protocols are now a
std::vector<std::string> rather than an encoded char*

BUG=none
TEST=SPDY still works with Google sites.


Review URL: http://codereview.chromium.org/8156001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@106093 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 332 insertions, 186 deletions

diff --git a/net/third_party/nss/patches/nextproto.patch b/net/third_party/nss/patches/nextproto.patch
index a01f240..46021b42 100644
--- a/net/third_party/nss/patches/nextproto.patch
+++ b/net/third_party/nss/patches/nextproto.patch
@@ -1,68 +1,89 @@
-From 6b594dc531e7a1d1d5bca2f0f78e7bc0ac3ff937 Mon Sep 17 00:00:00 2001
+From 3caa0f573d2637bfed99dcc0e5887fe3a52462ba Mon Sep 17 00:00:00 2001
 From: Adam Langley <agl@chromium.org>
 Date: Mon, 3 Oct 2011 12:19:28 -0400
-Subject: [PATCH] nextproto.patch
+Subject: [PATCH 01/15] nextproto.patch
 
 ---
- mozilla/security/nss/cmd/tstclnt/tstclnt.c |    6 ++
- mozilla/security/nss/lib/ssl/ssl.def       |    7 ++
- mozilla/security/nss/lib/ssl/ssl.h         |   12 +++
- mozilla/security/nss/lib/ssl/ssl3con.c     |   54 ++++++++++++
- mozilla/security/nss/lib/ssl/ssl3ext.c     |  122 +++++++++++++++++++++++++++-
- mozilla/security/nss/lib/ssl/ssl3prot.h    |    3 +-
- mozilla/security/nss/lib/ssl/sslimpl.h     |   24 ++++++
- mozilla/security/nss/lib/ssl/sslsock.c     |   74 +++++++++++++++++
- mozilla/security/nss/lib/ssl/sslt.h        |    3 +-
- 9 files changed, 302 insertions(+), 3 deletions(-)
+ mozilla/security/nss/lib/ssl/ssl.def    |    6 ++
+ mozilla/security/nss/lib/ssl/ssl.h      |   51 ++++++++++++
+ mozilla/security/nss/lib/ssl/ssl3con.c  |   54 +++++++++++++
+ mozilla/security/nss/lib/ssl/ssl3ext.c  |  104 ++++++++++++++++++++++++-
+ mozilla/security/nss/lib/ssl/ssl3prot.h |    3 +-
+ mozilla/security/nss/lib/ssl/sslerr.h   |    2 +
+ mozilla/security/nss/lib/ssl/sslimpl.h  |   21 +++++
+ mozilla/security/nss/lib/ssl/sslsock.c  |  131 +++++++++++++++++++++++++++++++
+ mozilla/security/nss/lib/ssl/sslt.h     |    3 +-
+ 9 files changed, 372 insertions(+), 3 deletions(-)
 
-diff --git a/mozilla/security/nss/cmd/tstclnt/tstclnt.c b/mozilla/security/nss/cmd/tstclnt/tstclnt.c
-index 55684e6..d209a33 100644
---- a/mozilla/security/nss/cmd/tstclnt/tstclnt.c
-+++ b/mozilla/security/nss/cmd/tstclnt/tstclnt.c
-@@ -868,6 +868,12 @@ int main(int argc, char **argv)
- 	return 1;
-     }
- 
-+    rv = SSL_SetNextProtoNego(s, "\004flip\004http1.1", 10);
-+    if (rv != SECSuccess) {
-+	SECU_PrintError(progName, "error enabling next protocol negotiation");
-+	return 1;
-+    }
-+
-     /* enable false start. */
-     rv = SSL_OptionSet(s, SSL_ENABLE_FALSE_START, enableFalseStart);
-     if (rv != SECSuccess) {
 diff --git a/mozilla/security/nss/lib/ssl/ssl.def b/mozilla/security/nss/lib/ssl/ssl.def
-index d3f455c..a1f4b51 100644
+index d3f455c..5256ae2 100644
 --- a/mozilla/security/nss/lib/ssl/ssl.def
 +++ b/mozilla/security/nss/lib/ssl/ssl.def
-@@ -152,3 +152,10 @@ SSL_SNISocketConfigHook;
+@@ -152,3 +152,9 @@ SSL_SNISocketConfigHook;
  ;+    local:
  ;+*;
  ;+};
 +;+NSS_CHROMIUM {
 +;+    global:
-+SSL_GetNextProto;
-+SSL_SetNextProtoNego;
++SSL_SetNextProtoCallback;
 +;+    local:
 +;+*;
 +;+};
 diff --git a/mozilla/security/nss/lib/ssl/ssl.h b/mozilla/security/nss/lib/ssl/ssl.h
-index 4a9e89d..ffa973c 100644
+index 4a9e89d..2cf777d 100644
 --- a/mozilla/security/nss/lib/ssl/ssl.h
 +++ b/mozilla/security/nss/lib/ssl/ssl.h
-@@ -153,6 +153,18 @@ SSL_IMPORT SECStatus SSL_OptionSetDefault(PRInt32 option, PRBool on);
+@@ -153,6 +153,57 @@ SSL_IMPORT SECStatus SSL_OptionSetDefault(PRInt32 option, PRBool on);
  SSL_IMPORT SECStatus SSL_OptionGetDefault(PRInt32 option, PRBool *on);
  SSL_IMPORT SECStatus SSL_CertDBHandleSet(PRFileDesc *fd, CERTCertDBHandle *dbHandle);
  
++/* SSLNextProtoCallback is called, during the handshake, when the server has
++ * sent a Next Protocol Negotiation extension. |protos| and |protosLen| define
++ * a buffer which contains the server's advertisement. This data is guaranteed
++ * to be well formed per the NPN spec. |protoOut| is a buffer provided by the
++ * caller, of length 255 (the maximum allowed by the protocol).
++ * On successful return, the protocol to be announced to the server will be in
++ * |protoOut| and its length in |protoOutLen|. */
++typedef SECStatus (PR_CALLBACK *SSLNextProtoCallback)(
++    void *arg,
++    PRFileDesc *fd,
++    const unsigned char* protos,
++    unsigned int protosLen,
++    unsigned char* protoOut,
++    unsigned int* protoOutLen);
++
++/* SSL_SetNextProtoCallback sets a callback function to handle Next Protocol
++ * Negotiation. It causes a client to advertise NPN. */
++SSL_IMPORT SECStatus SSL_SetNextProtoCallback(PRFileDesc *fd,
++                                              SSLNextProtoCallback callback,
++                                              void *arg);
++
++/* SSL_SetNextProtoNego can be used as an alternative to
++ * SSL_SetNextProtoCallback. It also causes a client to advertise NPN and
++ * installs a default callback function which selects the first supported
++ * protocol in server-preference order. If no matching protocol is found it
++ * selects the first supported protocol.
++ *
++ * The supported protocols are specified in |data| in wire-format (8-bit
++ * length-prefixed). For example: "\010http/1.1\006spdy/2". */
 +SSL_IMPORT SECStatus SSL_SetNextProtoNego(PRFileDesc *fd,
 +					  const unsigned char *data,
-+					  unsigned short length);
++					  unsigned int length);
++/* SSL_GetNextProto can be used after a handshake on a socket where
++ * SSL_SetNextProtoNego was called to retrieve the result of the Next Protocol
++ * negotiation.
++ *
++ * state is set to one of the SSL_NEXT_PROTO_* constants. The negotiated
++ * protocol, if any, is written into buf, which must be at least buf_len bytes
++ * long. If the negotiated protocol is longer than this, it is truncated.  The
++ * number of bytes copied is written into *length. */
 +SSL_IMPORT SECStatus SSL_GetNextProto(PRFileDesc *fd,
 +				      int *state,
 +				      unsigned char *buf,
-+				      unsigned *length,
-+				      unsigned buf_len);
++				      unsigned int *length,
++				      unsigned int buf_len);
++
++// TODO(wtc): it may be a good idea to define these as an enum type.
 +#define SSL_NEXT_PROTO_NO_SUPPORT	0 /* No peer support                */
 +#define SSL_NEXT_PROTO_NEGOTIATED	1 /* Mutual agreement               */
 +#define SSL_NEXT_PROTO_NO_OVERLAP	2 /* No protocol overlap found      */
@@ -71,7 +92,7 @@ index 4a9e89d..ffa973c 100644
  ** Control ciphers that SSL uses. If on is non-zero then the named cipher
  ** is enabled, otherwise it is disabled. 
 diff --git a/mozilla/security/nss/lib/ssl/ssl3con.c b/mozilla/security/nss/lib/ssl/ssl3con.c
-index 8048913..e0cb4e9 100644
+index 8048913..8f860a9 100644
 --- a/mozilla/security/nss/lib/ssl/ssl3con.c
 +++ b/mozilla/security/nss/lib/ssl/ssl3con.c
 @@ -81,6 +81,7 @@ static SECStatus ssl3_InitState(             sslSocket *ss);
@@ -107,7 +128,7 @@ index 8048913..e0cb4e9 100644
 +    int padding_len;
 +    static const unsigned char padding[32] = {0};
 +
-+    if (ss->ssl3.nextProtoState == SSL_NEXT_PROTO_NO_SUPPORT)
++    if (ss->ssl3.nextProto.len == 0)
 +	return SECSuccess;
 +
 +    PORT_Assert( ss->opt.noLocks || ssl_HaveXmitBufLock(ss));
@@ -164,7 +185,7 @@ index 8048913..e0cb4e9 100644
  
  /* End of ssl3con.c */
 diff --git a/mozilla/security/nss/lib/ssl/ssl3ext.c b/mozilla/security/nss/lib/ssl/ssl3ext.c
-index becbfe9..fbd5a91 100644
+index becbfe9..36ac4de 100644
 --- a/mozilla/security/nss/lib/ssl/ssl3ext.c
 +++ b/mozilla/security/nss/lib/ssl/ssl3ext.c
 @@ -235,6 +235,7 @@ static const ssl3HelloExtensionHandler clientHelloHandlers[] = {
@@ -193,7 +214,7 @@ index becbfe9..fbd5a91 100644
      /* any extra entries will appear as { 0, NULL }    */
  };
  
-@@ -534,6 +537,123 @@ ssl3_SendSessionTicketXtn(
+@@ -534,6 +537,105 @@ ssl3_SendSessionTicketXtn(
      return -1;
  }
  
@@ -206,12 +227,11 @@ index becbfe9..fbd5a91 100644
 +	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)
@@ -220,63 +240,46 @@ index becbfe9..fbd5a91 100644
 +
 +    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;
-+	}
-+
-+	i += (unsigned int)data->data[i] + 1;
-+    }
-+
-+  pick_first:
-+    ss->ssl3.nextProtoState = SSL_NEXT_PROTO_NO_OVERLAP;
-+    result = ss->opt.nextProtoNego.data;
++    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));
 +
-+  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;
 +}
 +
@@ -288,7 +291,7 @@ index becbfe9..fbd5a91 100644
 +    PRInt32 extension_length;
 +
 +    /* Renegotiations do not send this extension. */
-+    if (ss->opt.nextProtoNego.len == 0 || ss->firstHsDone) {
++    if (!ss->nextProtoCallback || ss->firstHsDone) {
 +	return 0;
 +    }
 +
@@ -331,48 +334,58 @@ index 4702fcc..f3c950e 100644
  } SSL3HandshakeType;
  
  typedef struct {
+diff --git a/mozilla/security/nss/lib/ssl/sslerr.h b/mozilla/security/nss/lib/ssl/sslerr.h
+index a2f6524..c76ffa9 100644
+--- a/mozilla/security/nss/lib/ssl/sslerr.h
++++ b/mozilla/security/nss/lib/ssl/sslerr.h
+@@ -203,6 +203,8 @@ SSL_ERROR_RX_UNEXPECTED_UNCOMPRESSED_RECORD	= (SSL_ERROR_BASE + 114),
+ 
+ SSL_ERROR_WEAK_SERVER_EPHEMERAL_DH_KEY  = (SSL_ERROR_BASE + 115),
+ 
++SSL_ERROR_NEXT_PROTOCOL_DATA_INVALID	= (SSL_ERROR_BASE + 117),
++
+ SSL_ERROR_END_OF_LIST	/* let the c compiler determine the value of this. */
+ } SSLErrorCodes;
+ #endif /* NO_SECURITY_ERROR_ENUM */
 diff --git a/mozilla/security/nss/lib/ssl/sslimpl.h b/mozilla/security/nss/lib/ssl/sslimpl.h
-index 9af471d..d1c1181 100644
+index 9af471d..199c573 100644
 --- a/mozilla/security/nss/lib/ssl/sslimpl.h
 +++ b/mozilla/security/nss/lib/ssl/sslimpl.h
-@@ -313,6 +313,11 @@ typedef struct {
+@@ -313,6 +313,10 @@ typedef struct {
  #endif /* NSS_ENABLE_ECC */
  
  typedef struct sslOptionsStr {
-+    /* For clients, this is a validated list of protocols in preference order
-+     * and wire format. For servers, this is the list of support protocols,
-+     * also in wire format. */
++    /* If SSL_SetNextProtoNego has been called, then this contains the
++     * list of supported protocols. */
 +    SECItem      nextProtoNego;
 +
      unsigned int useSecurity		: 1;  /*  1 */
      unsigned int useSocks		: 1;  /*  2 */
      unsigned int requestCertificate	: 1;  /*  3 */
-@@ -786,6 +791,7 @@ const ssl3CipherSuiteDef *suite_def;
- #ifdef NSS_ENABLE_ECC
-     PRUint32              negotiatedECCurves; /* bit mask */
- #endif /* NSS_ENABLE_ECC */
-+    PRBool                nextProtoNego;/* Our peer has sent this extension */
- } SSL3HandshakeState;
- 
- 
-@@ -827,6 +833,16 @@ struct ssl3StateStr {
+@@ -827,6 +831,13 @@ struct ssl3StateStr {
      PRBool               initialized;
      SSL3HandshakeState   hs;
      ssl3CipherSpec       specs[2];	/* one is current, one is pending. */
 +
 +    /* In a client: if the server supports Next Protocol Negotiation, then
-+     * this is the protocol that was requested.
-+     * In a server: this is the protocol that the client requested via Next
-+     * Protocol Negotiation.
++     * this is the protocol that was negotiated.
 +     *
-+     * In either case, if the data pointer is non-NULL, then it is malloced
-+     * data.  */
++     * If the data pointer is non-NULL, then it is malloced data.  */
 +    SECItem		nextProto;
-+    int			nextProtoState;	/* See SSL_NEXT_PROTO_* defines */
++    int			nextProtoState; /* See NEXT_PROTO_* defines */
  };
  
  typedef struct {
-@@ -1494,8 +1510,12 @@ extern SECStatus ssl3_HandleSupportedPointFormatsXtn(sslSocket * ss,
+@@ -1058,6 +1069,8 @@ const unsigned char *  preferredCipher;
+     SSLHandshakeCallback      handshakeCallback;
+     void                     *handshakeCallbackData;
+     void                     *pkcs11PinArg;
++    SSLNextProtoCallback      nextProtoCallback;
++    void                     *nextProtoArg;
+ 
+     PRIntervalTime            rTimeout; /* timeout for NSPR I/O */
+     PRIntervalTime            wTimeout; /* timeout for NSPR I/O */
+@@ -1494,8 +1507,12 @@ extern SECStatus ssl3_HandleSupportedPointFormatsXtn(sslSocket * ss,
  			PRUint16 ex_type, SECItem *data);
  extern SECStatus ssl3_ClientHandleSessionTicketXtn(sslSocket *ss,
  			PRUint16 ex_type, SECItem *data);
@@ -385,7 +398,7 @@ index 9af471d..d1c1181 100644
  
  /* ClientHello and ServerHello extension senders.
   * Note that not all extension senders are exposed here; only those that
-@@ -1526,6 +1546,10 @@ extern PRInt32 ssl3_SendSupportedCurvesXtn(sslSocket *ss,
+@@ -1526,6 +1543,10 @@ extern PRInt32 ssl3_SendSupportedCurvesXtn(sslSocket *ss,
  extern PRInt32 ssl3_SendSupportedPointFormatsXtn(sslSocket *ss,
  			PRBool append, PRUint32 maxBytes);
  #endif
@@ -397,7 +410,7 @@ index 9af471d..d1c1181 100644
  /* call the registered extension handlers. */
  extern SECStatus ssl3_HandleHelloExtensions(sslSocket *ss, 
 diff --git a/mozilla/security/nss/lib/ssl/sslsock.c b/mozilla/security/nss/lib/ssl/sslsock.c
-index bc770a1..4c8fbfd 100644
+index bc770a1..769ea0a 100644
 --- a/mozilla/security/nss/lib/ssl/sslsock.c
 +++ b/mozilla/security/nss/lib/ssl/sslsock.c
 @@ -163,6 +163,7 @@ static const sslSocketOps ssl_secure_ops = {	/* SSL. */
@@ -419,16 +432,14 @@ index bc770a1..4c8fbfd 100644
      PORT_Assert(!ss->xtnData.sniNameArr);
      if (ss->xtnData.sniNameArr) {
          PORT_Free(ss->xtnData.sniNameArr);
-@@ -1266,6 +1271,75 @@ SSL_ImportFD(PRFileDesc *model, PRFileDesc *fd)
+@@ -1266,6 +1271,132 @@ SSL_ImportFD(PRFileDesc *model, PRFileDesc *fd)
      return fd;
  }
  
-+/* SSL_SetNextProtoNego sets the list of supported protocols for the given
-+ * socket. The list is a series of 8-bit, length prefixed strings. */
 +SECStatus
-+SSL_SetNextProtoNego(PRFileDesc *fd, const unsigned char *data,
-+		     unsigned short length)
-+{
++SSL_SetNextProtoCallback(PRFileDesc *fd,
++                         SSLNextProtoCallback callback,
++                         void *arg) {
 +    sslSocket *ss = ssl_FindSocket(fd);
 +
 +    if (!ss) {
@@ -437,6 +448,74 @@ index bc770a1..4c8fbfd 100644
 +	return SECFailure;
 +    }
 +
++    ssl_GetSSL3HandshakeLock(ss);
++    ss->nextProtoCallback = callback;
++    ss->nextProtoArg = arg;
++    ssl_ReleaseSSL3HandshakeLock(ss);
++}
++
++/* NextProtoStandardCallback is set as an NPN callback for the case when the
++ * user of the sockets wants the standard selection algorithm. */
++static SECStatus
++NextProtoStandardCallback(void *arg,
++			  PRFileDesc *fd,
++			  const unsigned char *protos,
++			  unsigned int protos_len,
++			  unsigned char *protoOut,
++			  unsigned int *protoOutLen)
++{
++    unsigned int i, j;
++    const unsigned char *result;
++
++    sslSocket *ss = ssl_FindSocket(fd);
++    PORT_Assert(ss);
++
++    if (protos_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;
++    }
++
++    /* For each protocol in server preference, see if we support it. */
++    for (i = 0; i < protos_len; ) {
++	for (j = 0; j < ss->opt.nextProtoNego.len; ) {
++	    if (protos[i] == ss->opt.nextProtoNego.data[j] &&
++		memcmp(&protos[i+1], &ss->opt.nextProtoNego.data[j+1],
++		       protos[i]) == 0) {
++		/* We found a match. */
++		ss->ssl3.nextProtoState = SSL_NEXT_PROTO_NEGOTIATED;
++		result = &protos[i];
++		goto found;
++	    }
++	    j += (unsigned int)ss->opt.nextProtoNego.data[j] + 1;
++	}
++	i += (unsigned int)protos[i] + 1;
++    }
++
++pick_first:
++    ss->ssl3.nextProtoState = SSL_NEXT_PROTO_NO_OVERLAP;
++    result = ss->opt.nextProtoNego.data;
++
++found:
++    memcpy(protoOut, result + 1, result[0]);
++    *protoOutLen = result[0];
++    return SECSuccess;
++}
++
++SECStatus
++SSL_SetNextProtoNego(PRFileDesc *fd, const unsigned char *data,
++		     unsigned int length)
++{
++    SECStatus rv;
++
++    sslSocket *ss = ssl_FindSocket(fd);
++
++    if (!ss) {
++	SSL_DBG(("%d: SSL[%d]: bad socket in SSL_SetNextProtoNego",
++		 SSL_GETPID(), fd));
++	return SECFailure;
++    }
++
 +    if (ssl3_ValidateNextProtoNego(data, length) != SECSuccess)
 +	return SECFailure;
 +
@@ -453,18 +532,9 @@ index bc770a1..4c8fbfd 100644
 +    ss->opt.nextProtoNego.type = siBuffer;
 +    ssl_ReleaseSSL3HandshakeLock(ss);
 +
-+    return SECSuccess;
++    return SSL_SetNextProtoCallback(fd, NextProtoStandardCallback, NULL);
 +}
 +
-+/* SSL_GetNextProto reads the resulting Next Protocol Negotiation result for
-+ * the given socket. It's only valid to call this once the handshake has
-+ * completed.
-+ *
-+ * state is set to one of the SSL_NEXT_PROTO_* constants. The negotiated
-+ * protocol, if any, is written into buf, which must be at least buf_len
-+ * bytes long. If the negotiated protocol is longer than this, it is truncated.
-+ * The number of bytes copied is written into length.
-+ */
 +SECStatus
 +SSL_GetNextProto(PRFileDesc *fd, int *state, unsigned char *buf,
 +		 unsigned int *length, unsigned int buf_len)
diff --git a/net/third_party/nss/ssl/ssl.h b/net/third_party/nss/ssl/ssl.h
index 03535f3..debfbfb 100644
--- a/net/third_party/nss/ssl/ssl.h
+++ b/net/third_party/nss/ssl/ssl.h
@@ -157,14 +157,53 @@ SSL_IMPORT SECStatus SSL_OptionSetDefault(PRInt32 option, PRBool on);
 SSL_IMPORT SECStatus SSL_OptionGetDefault(PRInt32 option, PRBool *on);
 SSL_IMPORT SECStatus SSL_CertDBHandleSet(PRFileDesc *fd, CERTCertDBHandle *dbHandle);
 
+/* SSLNextProtoCallback is called, during the handshake, when the server has
+ * sent a Next Protocol Negotiation extension. |protos| and |protosLen| define
+ * a buffer which contains the server's advertisement. This data is guaranteed
+ * to be well formed per the NPN spec. |protoOut| is a buffer provided by the
+ * caller, of length 255 (the maximum allowed by the protocol).
+ * On successful return, the protocol to be announced to the server will be in
+ * |protoOut| and its length in |protoOutLen|. */
+typedef SECStatus (PR_CALLBACK *SSLNextProtoCallback)(
+    void *arg,
+    PRFileDesc *fd,
+    const unsigned char* protos,
+    unsigned int protosLen,
+    unsigned char* protoOut,
+    unsigned int* protoOutLen);
+
+/* SSL_SetNextProtoCallback sets a callback function to handle Next Protocol
+ * Negotiation. It causes a client to advertise NPN. */
+SSL_IMPORT SECStatus SSL_SetNextProtoCallback(PRFileDesc *fd,
+                                              SSLNextProtoCallback callback,
+                                              void *arg);
+
+/* SSL_SetNextProtoNego can be used as an alternative to
+ * SSL_SetNextProtoCallback. It also causes a client to advertise NPN and
+ * installs a default callback function which selects the first supported
+ * protocol in server-preference order. If no matching protocol is found it
+ * selects the first supported protocol.
+ *
+ * The supported protocols are specified in |data| in wire-format (8-bit
+ * length-prefixed). For example: "\010http/1.1\006spdy/2". */
 SSL_IMPORT SECStatus SSL_SetNextProtoNego(PRFileDesc *fd,
 					  const unsigned char *data,
-					  unsigned short length);
+					  unsigned int length);
+/* SSL_GetNextProto can be used after a handshake on a socket where
+ * SSL_SetNextProtoNego was called to retrieve the result of the Next Protocol
+ * negotiation.
+ *
+ * state is set to one of the SSL_NEXT_PROTO_* constants. The negotiated
+ * protocol, if any, is written into buf, which must be at least buf_len bytes
+ * long. If the negotiated protocol is longer than this, it is truncated.  The
+ * number of bytes copied is written into *length. */
 SSL_IMPORT SECStatus SSL_GetNextProto(PRFileDesc *fd,
 				      int *state,
 				      unsigned char *buf,
-				      unsigned *length,
-				      unsigned buf_len);
+				      unsigned int *length,
+				      unsigned int buf_len);
+
+// TODO(wtc): it may be a good idea to define these as an enum type.
 #define SSL_NEXT_PROTO_NO_SUPPORT	0 /* No peer support                */
 #define SSL_NEXT_PROTO_NEGOTIATED	1 /* Mutual agreement               */
 #define SSL_NEXT_PROTO_NO_OVERLAP	2 /* No protocol overlap found      */
diff --git a/net/third_party/nss/ssl/ssl3con.c b/net/third_party/nss/ssl/ssl3con.c
index 577086d..9dbf399 100644
--- a/net/third_party/nss/ssl/ssl3con.c
+++ b/net/third_party/nss/ssl/ssl3con.c
@@ -8557,7 +8557,7 @@ ssl3_SendNextProto(sslSocket *ss)
     int padding_len;
     static const unsigned char padding[32] = {0};
 
-    if (ss->ssl3.nextProtoState == SSL_NEXT_PROTO_NO_SUPPORT)
+    if (ss->ssl3.nextProto.len == 0)
 	return SECSuccess;
 
     PORT_Assert( ss->opt.noLocks || ssl_HaveXmitBufLock(ss));
diff --git a/net/third_party/nss/ssl/ssl3ext.c b/net/third_party/nss/ssl/ssl3ext.c
index e54b4fd..0c6b8e6 100644
--- a/net/third_party/nss/ssl/ssl3ext.c
+++ b/net/third_party/nss/ssl/ssl3ext.c
@@ -554,12 +554,11 @@ ssl3_ServerHandleNextProtoNegoXtn(sslSocket * ss, PRUint16 ex_type, SECItem *dat
 	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)
@@ -568,63 +567,46 @@ ssl3_ValidateNextProtoNego(const unsigned char* data, unsigned short length)
 
     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;
-	}
-
-	i += (unsigned int)data->data[i] + 1;
-    }
-
-  pick_first:
-    ss->ssl3.nextProtoState = SSL_NEXT_PROTO_NO_OVERLAP;
-    result = ss->opt.nextProtoNego.data;
+    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));
 
-  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;
 }
 
@@ -636,7 +618,7 @@ ssl3_ClientSendNextProtoNegoXtn(sslSocket * ss,
     PRInt32 extension_length;
 
     /* Renegotiations do not send this extension. */
-    if (ss->opt.nextProtoNego.len == 0 || ss->firstHsDone) {
+    if (!ss->nextProtoCallback || ss->firstHsDone) {
 	return 0;
     }
 
diff --git a/net/third_party/nss/ssl/sslerr.h b/net/third_party/nss/ssl/sslerr.h
index c940f95..8710a43 100644
--- a/net/third_party/nss/ssl/sslerr.h
+++ b/net/third_party/nss/ssl/sslerr.h
@@ -204,6 +204,7 @@ SSL_ERROR_RX_UNEXPECTED_UNCOMPRESSED_RECORD	= (SSL_ERROR_BASE + 114),
 SSL_ERROR_WEAK_SERVER_EPHEMERAL_DH_KEY  = (SSL_ERROR_BASE + 115),
 
 SSL_ERROR_RX_UNEXPECTED_CERT_STATUS	= (SSL_ERROR_BASE + 116),
+SSL_ERROR_NEXT_PROTOCOL_DATA_INVALID	= (SSL_ERROR_BASE + 117),
 
 SSL_ERROR_END_OF_LIST	/* let the c compiler determine the value of this. */
 } SSLErrorCodes;
diff --git a/net/third_party/nss/ssl/sslimpl.h b/net/third_party/nss/ssl/sslimpl.h
index d73a0e3..d9f2bd7 100644
--- a/net/third_party/nss/ssl/sslimpl.h
+++ b/net/third_party/nss/ssl/sslimpl.h
@@ -322,9 +322,8 @@ typedef struct {
 #endif /* NSS_ENABLE_ECC */
 
 typedef struct sslOptionsStr {
-    /* For clients, this is a validated list of protocols in preference order
-     * and wire format. For servers, this is the list of support protocols,
-     * also in wire format. */
+    /* If SSL_SetNextProtoNego has been called, then this contains the
+     * list of supported protocols. */
     SECItem      nextProtoNego;
 
     unsigned int useSecurity		: 1;  /*  1 */
@@ -827,7 +826,6 @@ const ssl3CipherSuiteDef *suite_def;
 #ifdef NSS_ENABLE_ECC
     PRUint32              negotiatedECCurves; /* bit mask */
 #endif /* NSS_ENABLE_ECC */
-    PRBool                nextProtoNego;/* Our peer has sent this extension */
 } SSL3HandshakeState;
 
 
@@ -886,14 +884,11 @@ struct ssl3StateStr {
     ssl3CipherSpec       specs[2];	/* one is current, one is pending. */
 
     /* In a client: if the server supports Next Protocol Negotiation, then
-     * this is the protocol that was requested.
-     * In a server: this is the protocol that the client requested via Next
-     * Protocol Negotiation.
+     * this is the protocol that was negotiated.
      *
-     * In either case, if the data pointer is non-NULL, then it is malloced
-     * data.  */
+     * If the data pointer is non-NULL, then it is malloced data.  */
     SECItem		nextProto;
-    int			nextProtoState;	/* See SSL_NEXT_PROTO_* defines */
+    int			nextProtoState; /* See NEXT_PROTO_* defines */
 };
 
 typedef struct {
@@ -1129,6 +1124,8 @@ const unsigned char *  preferredCipher;
     SSLHandshakeCallback      handshakeCallback;
     void                     *handshakeCallbackData;
     void                     *pkcs11PinArg;
+    SSLNextProtoCallback      nextProtoCallback;
+    void                     *nextProtoArg;
 
     PRIntervalTime            rTimeout; /* timeout for NSPR I/O */
     PRIntervalTime            wTimeout; /* timeout for NSPR I/O */
diff --git a/net/third_party/nss/ssl/sslsock.c b/net/third_party/nss/ssl/sslsock.c
index 8cc57ad..6f870f9 100644
--- a/net/third_party/nss/ssl/sslsock.c
+++ b/net/third_party/nss/ssl/sslsock.c
@@ -1310,12 +1310,10 @@ SSL_ImportFD(PRFileDesc *model, PRFileDesc *fd)
     return fd;
 }
 
-/* SSL_SetNextProtoNego sets the list of supported protocols for the given
- * socket. The list is a series of 8-bit, length prefixed strings. */
 SECStatus
-SSL_SetNextProtoNego(PRFileDesc *fd, const unsigned char *data,
-		     unsigned short length)
-{
+SSL_SetNextProtoCallback(PRFileDesc *fd,
+                         SSLNextProtoCallback callback,
+                         void *arg) {
     sslSocket *ss = ssl_FindSocket(fd);
 
     if (!ss) {
@@ -1324,6 +1322,74 @@ SSL_SetNextProtoNego(PRFileDesc *fd, const unsigned char *data,
 	return SECFailure;
     }
 
+    ssl_GetSSL3HandshakeLock(ss);
+    ss->nextProtoCallback = callback;
+    ss->nextProtoArg = arg;
+    ssl_ReleaseSSL3HandshakeLock(ss);
+}
+
+/* NextProtoStandardCallback is set as an NPN callback for the case when the
+ * user of the sockets wants the standard selection algorithm. */
+static SECStatus
+NextProtoStandardCallback(void *arg,
+			  PRFileDesc *fd,
+			  const unsigned char *protos,
+			  unsigned int protos_len,
+			  unsigned char *protoOut,
+			  unsigned int *protoOutLen)
+{
+    unsigned int i, j;
+    const unsigned char *result;
+
+    sslSocket *ss = ssl_FindSocket(fd);
+    PORT_Assert(ss);
+
+    if (protos_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;
+    }
+
+    /* For each protocol in server preference, see if we support it. */
+    for (i = 0; i < protos_len; ) {
+	for (j = 0; j < ss->opt.nextProtoNego.len; ) {
+	    if (protos[i] == ss->opt.nextProtoNego.data[j] &&
+		memcmp(&protos[i+1], &ss->opt.nextProtoNego.data[j+1],
+		       protos[i]) == 0) {
+		/* We found a match. */
+		ss->ssl3.nextProtoState = SSL_NEXT_PROTO_NEGOTIATED;
+		result = &protos[i];
+		goto found;
+	    }
+	    j += (unsigned int)ss->opt.nextProtoNego.data[j] + 1;
+	}
+	i += (unsigned int)protos[i] + 1;
+    }
+
+pick_first:
+    ss->ssl3.nextProtoState = SSL_NEXT_PROTO_NO_OVERLAP;
+    result = ss->opt.nextProtoNego.data;
+
+found:
+    memcpy(protoOut, result + 1, result[0]);
+    *protoOutLen = result[0];
+    return SECSuccess;
+}
+
+SECStatus
+SSL_SetNextProtoNego(PRFileDesc *fd, const unsigned char *data,
+		     unsigned int length)
+{
+    SECStatus rv;
+
+    sslSocket *ss = ssl_FindSocket(fd);
+
+    if (!ss) {
+	SSL_DBG(("%d: SSL[%d]: bad socket in SSL_SetNextProtoNego",
+		 SSL_GETPID(), fd));
+	return SECFailure;
+    }
+
     if (ssl3_ValidateNextProtoNego(data, length) != SECSuccess)
 	return SECFailure;
 
@@ -1340,18 +1406,9 @@ SSL_SetNextProtoNego(PRFileDesc *fd, const unsigned char *data,
     ss->opt.nextProtoNego.type = siBuffer;
     ssl_ReleaseSSL3HandshakeLock(ss);
 
-    return SECSuccess;
+    return SSL_SetNextProtoCallback(fd, NextProtoStandardCallback, NULL);
 }
 
-/* SSL_GetNextProto reads the resulting Next Protocol Negotiation result for
- * the given socket. It's only valid to call this once the handshake has
- * completed.
- *
- * state is set to one of the SSL_NEXT_PROTO_* constants. The negotiated
- * protocol, if any, is written into buf, which must be at least buf_len
- * bytes long. If the negotiated protocol is longer than this, it is truncated.
- * The number of bytes copied is written into length.
- */
 SECStatus
 SSL_GetNextProto(PRFileDesc *fd, int *state, unsigned char *buf,
 		 unsigned int *length, unsigned int buf_len)