cifs: Fix preauth hash corruption
commit 05946d4b7a7349ae58bfa2d51ae832e64a394c2d upstream.
smb311_update_preauth_hash() uses the shash in server->secmech without
appropriate locking, and this can lead to sessions corrupting each
other's preauth hashes.
The following script can easily trigger the problem:
#!/bin/sh -e
NMOUNTS=10
for i in $(seq $NMOUNTS);
mkdir -p /tmp/mnt$i
umount /tmp/mnt$i 2>/dev/null || :
done
while :; do
for i in $(seq $NMOUNTS); do
mount -t cifs //192.168.0.1/test /tmp/mnt$i -o ... &
done
wait
for i in $(seq $NMOUNTS); do
umount /tmp/mnt$i
done
done
Usually within seconds this leads to one or more of the mounts failing
with the following errors, and a "Bad SMB2 signature for message" is
seen in the server logs:
CIFS: VFS: \\192.168.0.1 failed to connect to IPC (rc=-13)
CIFS: VFS: cifs_mount failed w/return code = -13
Fix it by holding the server mutex just like in the other places where
the shashes are used.
Fixes: 8bd68c6e47abff34e4 ("CIFS: implement v3.11 preauth integrity")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
CC: <stable@vger.kernel.org>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
[aaptel: backport to kernel without CIFS_SESS_OP]
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed
