From: Eric Dumazet <edumazet@xxxxxxxxxx> [ Upstream commit e3d5ea2c011ecb16fb94c56a659364e6b30fac94 ] If recv_actor() returns an incorrect value, tcp_read_sock() might loop forever. Instead, issue a one time warning and make sure to make progress. Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx> Acked-by: John Fastabend <john.fastabend@xxxxxxxxx> Acked-by: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx> Acked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220302161723.3910001-2-eric.dumazet@xxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/ipv4/tcp.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index f48f1059b31a..ef68d55e0944 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1663,11 +1663,13 @@ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, if (!copied) copied = used; break; - } else if (used <= len) { - seq += used; - copied += used; - offset += used; } + if (WARN_ON_ONCE(used > len)) + used = len; + seq += used; + copied += used; + offset += used; + /* If recv_actor drops the lock (e.g. TCP splice * receive) the skb pointer might be invalid when * getting here: tcp_collapse might have deleted it -- 2.34.1
