diff options
| author | Pan Bian <bianpan2016@163.com> | 2018-11-23 15:56:33 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-12-17 21:55:10 +0100 |
| commit | d4327131dbe0147d0f07c5f0a65a0cb079bd2caa (patch) | |
| tree | 815158f2d2b3f0a4c42115fbdb39947777c37935 /fs/exportfs/expfs.c | |
| parent | 476bea0f653c47228d22975a16858a080de04993 (diff) | |
exportfs: do not read dentry after free
[ 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: a056cc8934c("exportfs: stop retrying once we race with
rename/remove")
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs/exportfs/expfs.c')
| -rw-r--r-- | fs/exportfs/expfs.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index 714cd37a6ba3..6599c6124552 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -76,7 +76,7 @@ static bool dentry_connected(struct dentry *dentry) struct dentry *parent = dget_parent(dentry); dput(dentry); - if (IS_ROOT(dentry)) { + if (dentry == parent) { dput(parent); return false; } |