tree 943469c97f321cbbad718d32889bb33a04cf712a
parent fc6d0f65f22040c6cc8a5ce032bf90252629de50
author Wang Weiyang <wangweiyang2@huawei.com> 1666697461 +0800
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1674030398 +0100

device_cgroup: Roll back to original exceptions after copy failure

commit e68bfbd3b3c3a0ec3cf8c230996ad8cabe90322f upstream.

When add the 'a *:* rwm' entry to devcgroup A's whitelist, at first A's
exceptions will be cleaned and A's behavior is changed to
DEVCG_DEFAULT_ALLOW. Then parent's exceptions will be copyed to A's
whitelist. If copy failure occurs, just return leaving A to grant
permissions to all devices. And A may grant more permissions than
parent.

Backup A's whitelist and recover original exceptions after copy
failure.

Cc: stable@vger.kernel.org
Fixes: 4cef7299b478 ("device_cgroup: add proper checking when changing default behavior")
Signed-off-by: Wang Weiyang <wangweiyang2@huawei.com>
Reviewed-by: Aristeu Rozanski <aris@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>