tcp: Add TCP_USER_TIMEOUT negative value check

[ Upstream commit 42493570100b91ef663c4c6f0c0fdab238f9d3c2 ]

TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int. But
patch "tcp: Add TCP_USER_TIMEOUT socket option"(dca43c75) didn't check the negative
values. If a user assign -1 to it, the socket will set successfully and wait
for 4294967295 miliseconds. This patch add a negative value check to avoid
this issue.

Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 11ba922..ad466a7 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2391,7 +2391,10 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
                /* Cap the max timeout in ms TCP will retry/retrans
                 * before giving up and aborting (ETIMEDOUT) a connection.
                 */
-               icsk->icsk_user_timeout = msecs_to_jiffies(val);
+               if (val < 0)
+                       err = -EINVAL;
+               else
+                       icsk->icsk_user_timeout = msecs_to_jiffies(val);
                break;
        default:
                err = -ENOPROTOOPT;