udp: fix race between close() and udp_abort()

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[ Upstream commit a8b897c7bc ]

Kaustubh reported and diagnosed a panic in udp_lib_lookup().
The root cause is udp_abort() racing with close(). Both
racing functions acquire the socket lock, but udp{v6}_destroy_sock()
release it before performing destructive actions.

We can't easily extend the socket lock scope to avoid the race,
instead use the SOCK_DEAD flag to prevent udp_abort from doing
any action when the critical race happens.

Diagnosed-and-tested-by: Kaustubh Pandey <kapandey@codeaurora.org>
Fixes: 5d77dca828 ("net: diag: support SOCK_DESTROY for UDP sockets")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Paolo Abeni 2021-06-09 11:49:01 +02:00 • committed by Greg Kroah-Hartman

parent 7dd7b1e4d9

commit 8729ec8a22

2 changed files with 13 additions and 0 deletions

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10

net/ipv4/udp.c

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3

net/ipv6/udp.c

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