net: don't add padding extension for SSLv3.

net/third_party/nss/patches/paddingextension.patch

 diff --git a/nss/lib/ssl/ssl3con.c b/nss/lib/ssl/ssl3con.c
-index 8b8b758..567d481 100644
+index 8b8b758..882e356 100644
 --- a/nss/lib/ssl/ssl3con.c
 +++ b/nss/lib/ssl/ssl3con.c
 @@ -4975,6 +4975,7 @@ ssl3_SendClientHello(sslSocket *ss, PRBool resending)
      PRBool           isTLS = PR_FALSE;
      PRBool           requestingResume = PR_FALSE;
      PRInt32          total_exten_len = 0;
 +    unsigned         paddingExtensionLen;
      unsigned         numCompressionMethods;
      PRInt32          flags;
  
 @@ -5241,6 +5242,20 @@ ssl3_SendClientHello(sslSocket *ss, PRBool resending)
         length += 1 + ss->ssl3.hs.cookieLen;
      }
  
 +    /* A padding extension may be included to ensure that the record containing
 +     * the ClientHello doesn't have a length between 256 and 511 bytes
 +     * (inclusive). Initial, ClientHello records with such lengths trigger bugs
 +     * in F5 devices.
 +     *
 +     * This is not done for DTLS nor for renegotiation. */
-+    if (!IS_DTLS(ss) && !ss->firstHsDone) {
++    if (!IS_DTLS(ss) && isTLS && !ss->firstHsDone) {
 +        paddingExtensionLen = ssl3_CalculatePaddingExtensionLength(length);
 +        total_exten_len += paddingExtensionLen;
 +        length += paddingExtensionLen;
 +    } else {
 +        paddingExtensionLen = 0;
 +    }
 +
      rv = ssl3_AppendHandshakeHeader(ss, client_hello, length);
      if (rv != SECSuccess) {
         return rv;      /* err set by ssl3_AppendHandshake* */
 @@ -5360,6 +5375,13 @@ ssl3_SendClientHello(sslSocket *ss, PRBool resending)
             return SECFailure;
         }
         maxBytes -= extLen;
 +
 +       extLen = ssl3_AppendPaddingExtension(ss, paddingExtensionLen, maxBytes);
 +       if (extLen < 0) {
 +           return SECFailure;
 +       }
 +       maxBytes -= extLen;
 +
         PORT_Assert(!maxBytes);
      } 
      if (ss->ssl3.hs.sendingSCSV) {
 diff --git a/nss/lib/ssl/ssl3ext.c b/nss/lib/ssl/ssl3ext.c
-index 0415770..8be042e 100644
+index 0415770..cdebcc9 100644
 --- a/nss/lib/ssl/ssl3ext.c
 +++ b/nss/lib/ssl/ssl3ext.c
 @@ -2297,3 +2297,56 @@ ssl3_ClientSendSigAlgsXtn(sslSocket * ss, PRBool append, PRUint32 maxBytes)
  loser:
      return -1;
  }
 +
 +unsigned int
 +ssl3_CalculatePaddingExtensionLength(unsigned int clientHelloLength)
 +{
@@ skipping 11 matching lines @@
 +     if (extensionLength < 4) {
 +        extensionLength = 4;
 +     }
 +
 +     return extensionLength;
 +}
 +
 +/* ssl3_AppendPaddingExtension possibly adds an extension which ensures that a
 + * ClientHello record is either < 256 bytes or is >= 512 bytes. This ensures
 + * that we don't trigger bugs in F5 products. */
-+unsigned int
++PRInt32
 +ssl3_AppendPaddingExtension(sslSocket *ss, unsigned int extensionLen,
 +                           PRUint32 maxBytes)
 +{
 +    unsigned int paddingLen = extensionLen - 4;
 +    unsigned char padding[256];
 +
 +    if (extensionLen == 0) {
 +       return 0;
 +    }
 +
 +    if (extensionLen < 4 ||
 +       extensionLen > maxBytes ||
 +       paddingLen > sizeof(padding)) {
 +       PORT_Assert(0);
-+       return 0;
++       return -1;
 +    }
 +
 +    if (SECSuccess != ssl3_AppendHandshakeNumber(ss, ssl_padding_xtn, 2))
 +       return -1;
 +    if (SECSuccess != ssl3_AppendHandshakeNumber(ss, paddingLen, 2))
 +       return -1;
 +    memset(padding, ' ', paddingLen);
 +    if (SECSuccess != ssl3_AppendHandshake(ss, padding, paddingLen))
 +       return -1;
 +
 +    return extensionLen;
 +}
 diff --git a/nss/lib/ssl/sslimpl.h b/nss/lib/ssl/sslimpl.h
-index 614eed1..621f25e 100644
+index 614eed1..9c789bf 100644
 --- a/nss/lib/ssl/sslimpl.h
 +++ b/nss/lib/ssl/sslimpl.h
 @@ -237,6 +237,13 @@ extern PRInt32
  ssl3_CallHelloExtensionSenders(sslSocket *ss, PRBool append, PRUint32 maxBytes,
                                 const ssl3HelloExtensionSender *sender);
  
 +extern unsigned int
 +ssl3_CalculatePaddingExtensionLength(unsigned int clientHelloLength);
 +
-+extern unsigned int
++extern PRInt32
 +ssl3_AppendPaddingExtension(sslSocket *ss, unsigned int extensionLen,
 +                           PRUint32 maxBytes);
 +
  /* Socket ops */
  struct sslSocketOpsStr {
      int         (*connect) (sslSocket *, const PRNetAddr *);
 diff --git a/nss/lib/ssl/sslt.h b/nss/lib/ssl/sslt.h
 index a8007d8..e4d188f 100644
 --- a/nss/lib/ssl/sslt.h
 +++ b/nss/lib/ssl/sslt.h
 @@ -205,9 +205,10 @@ typedef enum {
      ssl_session_ticket_xtn           = 35,
      ssl_next_proto_nego_xtn          = 13172,
      ssl_channel_id_xtn               = 30031,
 +    ssl_padding_xtn                  = 35655,
      ssl_renegotiation_info_xtn       = 0xff01  /* experimental number */
  } SSLExtensionType;
  
 -#define SSL_MAX_EXTENSIONS             11
 +#define SSL_MAX_EXTENSIONS             11 /* doesn't include ssl_padding_xtn. */
  
  #endif /* __sslt_h_ */