---

yaml --- r: 377003 b: refs/heads/master c: 409b545 h: refs/heads/master i: 377001: 487b238 376999: 586477d v: v3
git-mirror · Jun 5, 2013 · a0478dc · a0478dc
1 parent d0b2d49
commit a0478dc
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Showing 2 changed files with 7 additions and 1 deletion.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 37bc4f8dfa72fb43b84381abca39cfdbbc8ff2df
+refs/heads/master: 409b545ac10d9548929557a75ad86540f59a2c83
diff --git a/trunk/net/netfilter/xt_TCPMSS.c b/trunk/net/netfilter/xt_TCPMSS.c
@@ -125,6 +125,12 @@ tcpmss_mangle_packet(struct sk_buff *skb,
 
 	skb_put(skb, TCPOLEN_MSS);
 
+	/* RFC 879 states that the default MSS is 536 without specific
+	 * knowledge that the destination host is prepared to accept larger.
+	 * Since no MSS was provided, we MUST NOT set a value > 536.
+	 */
+	newmss = min(newmss, (u16)536);
+
 	opt = (u_int8_t *)tcph + sizeof(struct tcphdr);
 	memmove(opt + TCPOLEN_MSS, opt, tcplen - sizeof(struct tcphdr));