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>

1 files changed, 1 insertions, 1 deletions

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;