mptcp: avoid potential infinite loop in mptcp_recvmsg()

If a packet is ready in receive queue, and application isssues
a recvmsg()/recvfrom()/recvmmsg() request asking for zero bytes,
we hang in mptcp_recvmsg().

Fixes: ea4ca586b1 ("mptcp: refine MPTCP-level ack scheduling")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Link: https://lore.kernel.org/r/20201202171657.1185108-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2020-12-02 09:16:57 -08:00 committed by Jakub Kicinski
parent 2ce5a30711
commit 05e3ecea4a

View file

@ -1921,7 +1921,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
len = min_t(size_t, len, INT_MAX);
target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
for (;;) {
while (copied < len) {
int bytes_read, old_space;
bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied);