diff options
| author | Pan Bian <bianpan2016@163.com> | 2018-11-23 15:56:33 +0800 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2019-02-11 17:54:10 +0000 |
| commit | bc78b2c9553a06c48e6181f4b88f064f45661a3c (patch) | |
| tree | 41bb685379219e5729a9041ad5949917191b3cd0 /fs | |
| parent | 225ef25362d19fc1fb3870deca0b3110303e99eb (diff) | |
exportfs: do not read dentry after free
commit 2084ac6c505a58f7efdec13eba633c6aaa085ca5 upstream.
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: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'fs')
| -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 1939315d1b5a..78ff747c4fad 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; } |