1 files changed, 1 insertions, 1 deletions

diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 90f6544c13e2..51fdbb490437 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -245,7 +245,7 @@ bool cookie_check_timestamp(struct tcp_options_received *tcp_opt, bool *ecn_ok)
         if (!sysctl_tcp_timestamps)
                 return false;
 
-        tcp_opt->sack_ok = (options >> 4) & 0x1;
+        tcp_opt->sack_ok = (options & (1 << 4)) ? TCP_SACK_SEEN : 0;
         *ecn_ok = (options >> 5) & 1;
         if (*ecn_ok && !sysctl_tcp_ecn)
                 return false;