From a6fa56c0e480a16e83bee770d2e59f9ed8d08fbc Mon Sep 17 00:00:00 2001
From: Nikolay Kuratov <kniv@yandex-team.ru>
Date: Mon, 11 Dec 2023 19:23:17 +0300
Subject: [PATCH] vsock/virtio: Fix unsigned integer wrap around in
 virtio_transport_has_space()

[ Upstream commit 60316d7f10b17a7ebb1ead0642fee8710e1560e0 ]

We need to do signed arithmetic if we expect condition
`if (bytes < 0)` to be possible

Found by Linux Verification Center (linuxtesting.org) with SVACE

Fixes: 06a8fc78367d ("VSOCK: Introduce virtio_vsock_common.ko")
Signed-off-by: Nikolay Kuratov <kniv@yandex-team.ru>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20231211162317.4116625-1-kniv@yandex-team.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/vmw_vsock/virtio_transport_common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 93c11ffae92bb..e0bb83f5746c6 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -372,7 +372,7 @@ static s64 virtio_transport_has_space(struct vsock_sock *vsk)
 	struct virtio_vsock_sock *vvs = vsk->trans;
 	s64 bytes;
 
-	bytes = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
+	bytes = (s64)vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
 	if (bytes < 0)
 		bytes = 0;
 
-- 
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