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| author | Pan Bian <bianpan2016@163.com> | 2018-11-23 15:56:33 +0800 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2018-11-23 09:08:17 -0500 |
| commit | 2084ac6c505a58f7efdec13eba633c6aaa085ca5 (patch) | |
| tree | 11c18c7638bbeb0a09ee26cacd61f3a98ad893e8 /fs/exportfs | |
| parent | 909e22e05353a783c526829427e9a8de122fba9c (diff) | |
| download | lwn-2084ac6c505a58f7efdec13eba633c6aaa085ca5.tar.gz lwn-2084ac6c505a58f7efdec13eba633c6aaa085ca5.zip | |
exportfs: do not read dentry after free
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>
Diffstat (limited to 'fs/exportfs')
| -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 c8a3dfda1764..c69927bed4ef 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -77,7 +77,7 @@ 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; } |