From: Amir Goldstein <amir73il@gmail.com>
Date: Wed, 10 Oct 2018 16:10:06 +0000 (+0300)
Subject: ovl: fix error handling in ovl_verify_set_fh()
X-Git-Tag: rel_imx_4.19.35_1.1.0~8665
X-Git-Url: https://git.somdevices.com/?a=commitdiff_plain;h=37403ba3c4135da033714bfba42fdc0c23ecbdeb;p=linux.git

ovl: fix error handling in ovl_verify_set_fh()

commit babf4770be0adc69e6d2de150f4040f175e24beb upstream.

We hit a BUG on kfree of an ERR_PTR()...

Reported-by: syzbot+ff03fe05c717b82502d0@syzkaller.appspotmail.com
Fixes: 8b88a2e64036 ("ovl: verify upper root dir matches lower root dir")
Cc: <stable@vger.kernel.org> # v4.13
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 9c0ca6a7becf..efd372312ef1 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -422,8 +422,10 @@ int ovl_verify_set_fh(struct dentry *dentry, const char *name,
 
 	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)