From 72014e7745cc8250bb8f27bd78694dfd3f1b5773 Mon Sep 17 00:00:00 2001
From: Vasiliy Kovalev <kovalev@altlinux.org>
Date: Tue, 19 Nov 2024 18:58:17 +0300
Subject: [PATCH] ovl: Filter invalid inodes with missing lookup function
commit c8b359dddb418c60df1a69beea01d1b3322bfe83 upstream.
Add a check to the ovl_dentry_weird() function to prevent the
processing of directory inodes that lack the lookup function.
This is important because such inodes can cause errors in overlayfs
when passed to the lowerstack.
Reported-by: syzbot+a8c9d476508bd14a90e5@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=a8c9d476508bd14a90e5
Suggested-by: Miklos Szeredi <miklos@szeredi.hu>
Link: https://lore.kernel.org/linux-unionfs/CAJfpegvx-oS9XGuwpJx=Xe28_jzWx5eRo1y900_ZzWY+=gGzUg@mail.gmail.com/
Signed-off-by: Vasiliy Kovalev <kovalev@altlinux.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/overlayfs/util.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index edc9216f6e27a..8f080046c59d9 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -197,6 +197,9 @@ void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry,
bool ovl_dentry_weird(struct dentry *dentry)
{
+ if (!d_can_lookup(dentry) && !d_is_file(dentry) && !d_is_symlink(dentry))
+ return true;
+
return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
DCACHE_MANAGE_TRANSIT |
DCACHE_OP_HASH |
--
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