[PATCH 5.2 280/313] ovl: Fix dereferencing possible ERR_PTR()

From: Greg Kroah-Hartman
Date: Thu Oct 03 2019 - 13:07:31 EST


From: Ding Xiang <dingxiang@xxxxxxxxxxxxxxxxxxxx>

commit 97f024b9171e74c4443bbe8a8dce31b917f97ac5 upstream.

if ovl_encode_real_fh() fails, no memory was allocated
and the error in the error-valued pointer should be returned.

Fixes: 9b6faee07470 ("ovl: check ERR_PTR() return value from ovl_encode_fh()")
Signed-off-by: Ding Xiang <dingxiang@xxxxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v4.16+
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/overlayfs/export.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -227,9 +227,8 @@ static int ovl_d_to_fh(struct dentry *de
/* Encode an upper or lower file handle */
fh = ovl_encode_real_fh(enc_lower ? ovl_dentry_lower(dentry) :
ovl_dentry_upper(dentry), !enc_lower);
- err = PTR_ERR(fh);
if (IS_ERR(fh))
- goto fail;
+ return PTR_ERR(fh);

err = -EOVERFLOW;
if (fh->len > buflen)