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authorPan Bian <bianpan2016@163.com>2018-11-23 15:56:33 +0800
committerAl Viro <viro@zeniv.linux.org.uk>2018-11-23 09:08:17 -0500
commit2084ac6c505a58f7efdec13eba633c6aaa085ca5 (patch)
tree11c18c7638bbeb0a09ee26cacd61f3a98ad893e8 /fs/exportfs
parent909e22e05353a783c526829427e9a8de122fba9c (diff)
downloadlinux-stericsson-2084ac6c505a58f7efdec13eba633c6aaa085ca5.tar.gz
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.c2
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;
}