On Thu, Oct 07, 2021 at 07:05:36PM +0200, Jann Horn wrote:
From: Eric Dumazet edumazet@google.com
[ Upstream commit 35306eb23814444bd4021f8a1c3047d3cb0c8b2b ]
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 [backport note: 4.4 and 4.9 don't have SO_PEERGROUPS, only SO_PEERCRED] [backport note: got rid of sk_get_peer_cred(), no users in 4.4/4.9] Signed-off-by: Jann Horn jannh@google.com
include/net/sock.h | 2 ++ net/core/sock.c | 12 +++++++++--- net/unix/af_unix.c | 34 ++++++++++++++++++++++++++++------ 3 files changed, 39 insertions(+), 9 deletions(-)
Thanks, both now queued up.
greg k-h