From: Dmitry Popov <dp@highloadlab.com>
Date: Sun, 8 Aug 2010 03:24:28 +0000 (-0700)
Subject: tcp: no md5sig option size check bug
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ba78e2ddca844598c0efcbf2c76d73519a61b902;p=linux-beck.git

tcp: no md5sig option size check bug

tcp_parse_md5sig_option doesn't check md5sig option (TCPOPT_MD5SIG)
length, but tcp_v[46]_inbound_md5_hash assume that it's at least 16
bytes long.

Signed-off-by: Dmitry Popov <dp@highloadlab.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 3c426cb318e7..e663b78a2ef6 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3930,7 +3930,7 @@ u8 *tcp_parse_md5sig_option(struct tcphdr *th)
 			if (opsize < 2 || opsize > length)
 				return NULL;
 			if (opcode == TCPOPT_MD5SIG)
-				return ptr;
+				return opsize == TCPOLEN_MD5SIG ? ptr : NULL;
 		}
 		ptr += opsize - 2;
 		length -= opsize;