Commit 05e3ecea authored Dec 02, 2020 by Eric Dumazet Committed by Jakub Kicinski Dec 02, 2020

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: ea4ca586 ("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>

parent 2ce5a307

net/mptcp/protocol.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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);

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