https://github.com/torvalds/linux
Revision 35306eb23814444bd4021f8a1c3047d3cb0c8b2b authored by Eric Dumazet on 29 September 2021, 22:57:50 UTC, committed by David S. Miller on 30 September 2021, 13:18:40 UTC
Jann Horn reported that SO_PEERCRED and SO_PEERGROUPS implementations
are racy, as af_unix can concurrently change sk_peer_pid and sk_peer_cred.

In order to fix this issue, this patch adds a new spinlock that needs
to be used whenever these fields are read or written.

Jann also pointed out that l2cap_sock_get_peer_pid_cb() is currently
reading sk->sk_peer_pid which makes no sense, as this field
is only possibly set by AF_UNIX sockets.
We will have to clean this in a separate patch.
This could be done by reverting b48596d1dc25 "Bluetooth: L2CAP: Add get_peer_pid callback"
or implementing what was truly expected.

Fixes: 109f6e39fa07 ("af_unix: Allow SO_PEERCRED to work across namespaces.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Jann Horn <jannh@google.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 656ed8b
History
Tip revision: 35306eb23814444bd4021f8a1c3047d3cb0c8b2b authored by Eric Dumazet on 29 September 2021, 22:57:50 UTC
af_unix: fix races in sk_peer_pid and sk_peer_cred accesses
Tip revision: 35306eb
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