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| author | Paolo Abeni <pabeni@redhat.com> | 2021-06-09 11:49:01 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-06-23 14:42:42 +0200 |
| commit | 8729ec8a2238152a4afc212a331a6cd2c61aeeac (patch) | |
| tree | 7a0228e15434f7cfc2fbd74393d260e582e785ce /net/ipv4 | |
| parent | 7dd7b1e4d929a42116e6e75413d07ceb7a60c7ab (diff) | |
| download | linux-stable-8729ec8a2238152a4afc212a331a6cd2c61aeeac.tar.gz linux-stable-8729ec8a2238152a4afc212a331a6cd2c61aeeac.tar.bz2 linux-stable-8729ec8a2238152a4afc212a331a6cd2c61aeeac.zip | |
udp: fix race between close() and udp_abort()
[ Upstream commit a8b897c7bcd47f4147d066e22cc01d1026d7640e ]
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: 5d77dca82839 ("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>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/udp.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 9d28b2778e8f..fbb9a11fe4a3 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2569,6 +2569,9 @@ void udp_destroy_sock(struct sock *sk) { struct udp_sock *up = udp_sk(sk); bool slow = lock_sock_fast(sk); + + /* protects from races with udp_abort() */ + sock_set_flag(sk, SOCK_DEAD); udp_flush_pending_frames(sk); unlock_sock_fast(sk, slow); if (static_branch_unlikely(&udp_encap_needed_key)) { @@ -2819,10 +2822,17 @@ int udp_abort(struct sock *sk, int err) { lock_sock(sk); + /* udp{v6}_destroy_sock() sets it under the sk lock, avoid racing + * with close() + */ + if (sock_flag(sk, SOCK_DEAD)) + goto out; + sk->sk_err = err; sk->sk_error_report(sk); __udp_disconnect(sk, 0); +out: release_sock(sk); return 0; |