NSS: add `balloon' extension to when we might hit the F5 bug.

net/third_party/nss/patches/balloonextension.patch

+diff --git a/nss/lib/ssl/ssl3con.c b/nss/lib/ssl/ssl3con.c
+index 8b8b758..f5b973b 100644
+--- a/nss/lib/ssl/ssl3con.c
++++ b/nss/lib/ssl/ssl3con.c
+@@ -4974,7 +4974,7 @@ ssl3_SendClientHello(sslSocket *ss, PRBool resending)
+     int              actual_count = 0;
+     PRBool           isTLS = PR_FALSE;
+     PRBool           requestingResume = PR_FALSE;
+-    PRInt32          total_exten_len = 0;
++    PRInt32          total_exten_len = 0, balloonExtensionLen;
+     unsigned         numCompressionMethods;
+     PRInt32          flags;
+ 
+@@ -5241,6 +5241,10 @@ ssl3_SendClientHello(sslSocket *ss, PRBool resending)
+        length += 1 + ss->ssl3.hs.cookieLen;
+     }
+ 
++    balloonExtensionLen = ssl3_CalculateBalloonExtensionLength(length);
++    total_exten_len += balloonExtensionLen;
++    length += balloonExtensionLen;
++
+     rv = ssl3_AppendHandshakeHeader(ss, client_hello, length);
+     if (rv != SECSuccess) {
+        return rv;      /* err set by ssl3_AppendHandshake* */
+@@ -5360,6 +5364,13 @@ ssl3_SendClientHello(sslSocket *ss, PRBool resending)
+            return SECFailure;
+        }
+        maxBytes -= extLen;
++
++       extLen = ssl3_AppendBalloonExtension(ss, balloonExtensionLen, 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..a596c37 100644
+--- a/nss/lib/ssl/ssl3ext.c
++++ b/nss/lib/ssl/ssl3ext.c
+@@ -2297,3 +2297,54 @@ ssl3_ClientSendSigAlgsXtn(sslSocket * ss, PRBool append, PRUint32 maxBytes)
+ loser:
+     return -1;
+ }
++
++PRInt32
++ssl3_CalculateBalloonExtensionLength(int clientHelloLength)
++{
++    int recordLength = clientHelloLength +
++                      1 /* handshake message type */ +
++                      3 /* handshake message length */;
++
++    if (recordLength < 256 || recordLength >= 512) {
++       return 0;
++    }
++
++    return 512 - recordLength;
++}
++
++/* ssl3_AppendBalloonExtension 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. */
++PRInt32
++ssl3_AppendBalloonExtension(sslSocket *ss, int extensionLen, PRUint32 maxBytes)
++{
++    SECStatus rv;
++    PRInt32 paddingLen = extensionLen - 4;
++    unsigned char *padding;
++
++    if (extensionLen == 0) {
++       return 0;
++    }
++
++    if (extensionLen > maxBytes) {
++       PORT_Assert(0);
++       return 0;
++    }
++
++    rv = ssl3_AppendHandshakeNumber(ss, ssl_balloon_xtn, 2);
++    if (rv != SECSuccess)
++       return -1;
++    rv = ssl3_AppendHandshakeNumber(ss, paddingLen, 2);
++    if (rv != SECSuccess)
++       return -1;
++    padding = PORT_Alloc(paddingLen);
++    if (!padding)
++       return -1;
++    memset(padding, ' ', paddingLen);
++    rv = ssl3_AppendHandshake(ss, padding, paddingLen);
++    PORT_Free(padding);
++    if (rv != SECSuccess)
++       return -1;
++
++    return extensionLen;
++}
+diff --git a/nss/lib/ssl/sslimpl.h b/nss/lib/ssl/sslimpl.h
+index 614eed1..0fa5087 100644
+--- a/nss/lib/ssl/sslimpl.h
++++ b/nss/lib/ssl/sslimpl.h
+@@ -237,6 +237,12 @@ extern PRInt32
+ ssl3_CallHelloExtensionSenders(sslSocket *ss, PRBool append, PRUint32 maxBytes,
+                                const ssl3HelloExtensionSender *sender);
+ 
++extern PRInt32
++ssl3_CalculateBalloonExtensionLength(int clientHelloLength);
++
++extern PRInt32
++ssl3_AppendBalloonExtension(sslSocket *ss, 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..542afd7 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_balloon_xtn                  = 35655,
+     ssl_renegotiation_info_xtn       = 0xff01  /* experimental number */
+ } SSLExtensionType;
+ 
+-#define SSL_MAX_EXTENSIONS             11
++#define SSL_MAX_EXTENSIONS             11 /* doesn't include ssl_balloon_xtn. */
+ 
+ #endif /* __sslt_h_ */