4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Amir Goldstein <amir73il@xxxxxxxxx>
commit babf4770be0adc69e6d2de150f4040f175e24beb upstream.
We hit a BUG on kfree of an ERR_PTR()...
Reported-by: syzbot+ff03fe05c717b82502d0@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 8b88a2e64036 ("ovl: verify upper root dir matches lower root dir")
Cc: <stable@xxxxxxxxxxxxxxx> # v4.13
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/overlayfs/namei.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -441,8 +441,10 @@ int ovl_verify_set_fh(struct dentry *den
fh = ovl_encode_real_fh(real, is_upper);
err = PTR_ERR(fh);
- if (IS_ERR(fh))
+ if (IS_ERR(fh)) {
+ fh = NULL;
goto fail;
+ }
err = ovl_verify_fh(dentry, name, fh);
if (set && err == -ENODATA)
