Replace the override_creds_light()/revert_creds_light() pairs of
operations with cred_guard()/cred_scoped_guard().
In ovl_nlink_start() use cred_scoped_guard(), because of
'goto', which can cause the cleanup flow to run on garbage memory.
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx>
---
fs/overlayfs/util.c | 24 ++++++++++--------------
1 file changed, 10 insertions(+), 14 deletions(-)
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 80caeb81c727..77b8d01829a4 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -1140,7 +1140,6 @@ static void ovl_cleanup_index(struct dentry *dentry)
int ovl_nlink_start(struct dentry *dentry)
{
struct inode *inode = d_inode(dentry);
- const struct cred *old_cred;
int err;
if (WARN_ON(!inode))
@@ -1177,15 +1176,15 @@ int ovl_nlink_start(struct dentry *dentry)
if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, inode))
return 0;
- old_cred = ovl_override_creds_light(dentry->d_sb);
- /*
- * The overlay inode nlink should be incremented/decremented IFF the
- * upper operation succeeds, along with nlink change of upper inode.
- * Therefore, before link/unlink/rename, we store the union nlink
- * value relative to the upper inode nlink in an upper inode xattr.
- */
- err = ovl_set_nlink_upper(dentry);
- revert_creds_light(old_cred);
+ cred_scoped_guard(ovl_creds(dentry->d_sb)) {
+ /*
+ * The overlay inode nlink should be incremented/decremented IFF the
+ * upper operation succeeds, along with nlink change of upper inode.
+ * Therefore, before link/unlink/rename, we store the union nlink
+ * value relative to the upper inode nlink in an upper inode xattr.
+ */
+ err = ovl_set_nlink_upper(dentry);
+ }
if (err)
goto out_drop_write;
@@ -1206,11 +1205,8 @@ void ovl_nlink_end(struct dentry *dentry)
ovl_drop_write(dentry);
if (ovl_test_flag(OVL_INDEX, inode) && inode->i_nlink == 0) {
- const struct cred *old_cred;
-
- old_cred = ovl_override_creds_light(dentry->d_sb);
+ cred_guard(ovl_creds(dentry->d_sb));
ovl_cleanup_index(dentry);
- revert_creds_light(old_cred);
}
ovl_inode_unlock(inode);
--
2.46.0
