tcp: md5: fix potential overestimation of TCP option space

[tomoyo/tomoyo-test1.git] / net / ipv4 / tcp_output.c

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index be6d22b..b184f03 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -755,8 +755,9 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb
                        min_t(unsigned int, eff_sacks,
                              (remaining - TCPOLEN_SACK_BASE_ALIGNED) /
                              TCPOLEN_SACK_PERBLOCK);
-               size += TCPOLEN_SACK_BASE_ALIGNED +
-                       opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
+               if (likely(opts->num_sack_blocks))
+                       size += TCPOLEN_SACK_BASE_ALIGNED +
+                               opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
        }
 
        return size;