diff options
| author | Soheil Hassas Yeganeh <soheil@google.com> | 2018-06-08 22:47:10 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-06-10 14:12:50 -0700 |
| commit | 867f816badc01e6da655028810d468c9f935b37c (patch) | |
| tree | 8638841a4e39647569a24e5021bfa45586c90a3b | |
| parent | b718e8c8f4f5920aaddc2e52d5e32f494c91129c (diff) | |
tcp: limit sk_rcvlowat by the maximum receive buffer
The user-provided value to setsockopt(SO_RCVLOWAT) can be
larger than the maximum possible receive buffer. Such values
mute POLLIN signals on the socket which can stall progress
on the socket.
Limit the user-provided value to half of the maximum receive
buffer, i.e., half of sk_rcvbuf when the receive buffer size
is set by the user, or otherwise half of sysctl_tcp_rmem[2].
Fixes: d1361840f8c5 ("tcp: fix SO_RCVLOWAT and RCVBUF autotuning")
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/tcp.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 2741953adaba..141acd92e58a 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1694,6 +1694,13 @@ EXPORT_SYMBOL(tcp_peek_len); /* Make sure sk_rcvbuf is big enough to satisfy SO_RCVLOWAT hint */ int tcp_set_rcvlowat(struct sock *sk, int val) { + int cap; + + if (sk->sk_userlocks & SOCK_RCVBUF_LOCK) + cap = sk->sk_rcvbuf >> 1; + else + cap = sock_net(sk)->ipv4.sysctl_tcp_rmem[2] >> 1; + val = min(val, cap); sk->sk_rcvlowat = val ? : 1; /* Check if we need to signal EPOLLIN right now */ @@ -1702,12 +1709,7 @@ int tcp_set_rcvlowat(struct sock *sk, int val) if (sk->sk_userlocks & SOCK_RCVBUF_LOCK) return 0; - /* val comes from user space and might be close to INT_MAX */ val <<= 1; - if (val < 0) - val = INT_MAX; - - val = min(val, sock_net(sk)->ipv4.sysctl_tcp_rmem[2]); if (val > sk->sk_rcvbuf) { sk->sk_rcvbuf = val; tcp_sk(sk)->window_clamp = tcp_win_from_space(sk, val); |