• Pan Bian's avatar
    exportfs: do not read dentry after free · d2139ee7
    Pan Bian authored
    [ Upstream commit 2084ac6c505a58f7efdec13eba633c6aaa085ca5 ]
    The function dentry_connected calls dput(dentry) to drop the previously
    acquired reference to dentry. In this case, dentry can be released.
    After that, IS_ROOT(dentry) checks the condition
    (dentry == dentry->d_parent), which may result in a use-after-free bug.
    This patch directly compares dentry with its parent obtained before
    dropping the reference.
    Fixes: a056cc89("exportfs: stop retrying once we race with
    Signed-off-by: default avatarPan Bian <bianpan2016@163.com>
    Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
    Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
expfs.c 13.8 KB