Commit 02b2faaf authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

tcp: fix various issues for sockets morphing to listen state

Dmitry Vyukov reported a divide by 0 triggered by syzkaller, exploiting
tcp_disconnect() path that was never really considered and/or used
before syzkaller ;)

I was not able to reproduce the bug, but it seems issues here are the
three possible actions that assumed they would never trigger on a
listener.

1) tcp_write_timer_handler
2) tcp_delack_timer_handler
3) MTU reduction

Only IPv6 MTU reduction was properly testing TCP_CLOSE and TCP_LISTEN
 states from tcp_v6_mtu_reduced()
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b73d2da8
......@@ -279,10 +279,13 @@ EXPORT_SYMBOL(tcp_v4_connect);
*/
void tcp_v4_mtu_reduced(struct sock *sk)
{
struct dst_entry *dst;
struct inet_sock *inet = inet_sk(sk);
u32 mtu = tcp_sk(sk)->mtu_info;
struct dst_entry *dst;
u32 mtu;
if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
return;
mtu = tcp_sk(sk)->mtu_info;
dst = inet_csk_update_pmtu(sk, mtu);
if (!dst)
return;
......
......@@ -249,7 +249,8 @@ void tcp_delack_timer_handler(struct sock *sk)
sk_mem_reclaim_partial(sk);
if (sk->sk_state == TCP_CLOSE || !(icsk->icsk_ack.pending & ICSK_ACK_TIMER))
if (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) ||
!(icsk->icsk_ack.pending & ICSK_ACK_TIMER))
goto out;
if (time_after(icsk->icsk_ack.timeout, jiffies)) {
......@@ -552,7 +553,8 @@ void tcp_write_timer_handler(struct sock *sk)
struct inet_connection_sock *icsk = inet_csk(sk);
int event;
if (sk->sk_state == TCP_CLOSE || !icsk->icsk_pending)
if (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) ||
!icsk->icsk_pending)
goto out;
if (time_after(icsk->icsk_timeout, jiffies)) {
......
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