tcp: warn on negative reordering values

Commit bafbb9c73241 ("tcp: eliminate negative reordering
in tcp_clean_rtx_queue") fixes an issue for negative
reordering metrics.

To be resilient to such errors, warn and return
when a negative metric is passed to tcp_update_reordering().

Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.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 bbadd79815a4c6665c1a832c5c415965d2275e2e..2fa55f57ac06584bfd9b555799ceb3bbfb7e1b4e 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -887,6 +887,9 @@ static void tcp_update_reordering(struct sock *sk, const int metric,
        struct tcp_sock *tp = tcp_sk(sk);
        int mib_idx;
 
+       if (WARN_ON_ONCE(metric < 0))
+               return;
+
        if (metric > tp->reordering) {
                tp->reordering = min(sysctl_tcp_max_reordering, metric);