ovl: during copy up, switch to mounter's creds early

[linux.git] / fs / overlayfs / inode.c

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index c75625c1efa36fafdd7d077b86f874cd6a16b7e7..ce5d7dfaf7693736ec08464677b78e0f40da26fb 100644 (file)
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -19,6 +19,7 @@ static int ovl_copy_up_truncate(struct dentry *dentry)
        struct dentry *parent;
        struct kstat stat;
        struct path lowerpath;
+       const struct cred *old_cred;
 
        parent = dget_parent(dentry);
        err = ovl_copy_up(parent);
@@ -26,12 +27,14 @@ static int ovl_copy_up_truncate(struct dentry *dentry)
                goto out_dput_parent;
 
        ovl_path_lower(dentry, &lowerpath);
-       err = vfs_getattr(&lowerpath, &stat);
-       if (err)
-               goto out_dput_parent;
 
-       stat.size = 0;
-       err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat);
+       old_cred = ovl_override_creds(dentry->d_sb);
+       err = vfs_getattr(&lowerpath, &stat);
+       if (!err) {
+               stat.size = 0;
+               err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat);
+       }
+       revert_creds(old_cred);
 
 out_dput_parent:
        dput(parent);