From: Al Viro <viro@zeniv.linux.org.uk>
To: Lizhi Xu <lizhi.xu@windriver.com>
Cc: syzbot+73d8fc29ec7cba8286fa@syzkaller.appspotmail.com,
almaz.alexandrovich@paragon-software.com, brauner@kernel.org,
jack@suse.cz, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, ntfs3@lists.linux.dev,
syzkaller-bugs@googlegroups.com
Subject: Re: [PATCH] fs: add check for symlink corrupted
Date: Fri, 15 Nov 2024 13:24:55 +0000 [thread overview]
Message-ID: <20241115132455.GS3387508@ZenIV> (raw)
In-Reply-To: <20241115130615.GR3387508@ZenIV>
On Fri, Nov 15, 2024 at 01:06:15PM +0000, Al Viro wrote:
> On Fri, Nov 15, 2024 at 05:49:08PM +0800, Lizhi Xu wrote:
> > syzbot reported a null-ptr-deref in pick_link. [1]
> > When symlink's inode is corrupted, the value of the i_link is 2 in this case,
> > it will trigger null pointer deref when accessing *res in pick_link().
> >
> > To avoid this issue, add a check for inode mode, return -EINVAL when it's
> > not symlink.
>
> NAK. Don't paper over filesystem bugs at pathwalk time - it's the wrong
> place for that. Fix it at in-core inode creation time.
BTW, seeing that ntfs doesn't even touch ->i_link, you are dealing
with aftermath of memory corruption, so it's definitely papering over
the actual bug here.
next prev parent reply other threads:[~2024-11-15 13:24 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-14 18:08 [syzbot] [ntfs3?] general protection fault in pick_link syzbot
2024-11-15 8:26 ` [syzbot] " syzbot
2024-11-15 9:49 ` [PATCH] fs: add check for symlink corrupted Lizhi Xu
2024-11-15 11:43 ` Jan Kara
2024-11-16 1:02 ` Lizhi Xu
2024-11-16 1:25 ` Al Viro
2024-11-15 13:06 ` Al Viro
2024-11-15 13:24 ` Al Viro [this message]
2024-11-16 1:39 ` Lizhi Xu
2024-11-16 2:32 ` Al Viro
2024-11-19 11:29 ` [PATCH V2] fs: improve the check of whether i_link has been set Lizhi Xu
2024-11-19 16:36 ` Al Viro
2024-11-20 3:04 ` [PATCH V3] fs/ntfs3: check if the inode is bad before creating symlink Lizhi Xu
2024-11-20 16:10 ` Al Viro
2024-11-21 3:13 ` Lizhi Xu
2024-11-21 3:55 ` Al Viro
2024-11-21 5:27 ` Lizhi Xu
2024-11-22 7:49 ` Lizhi Xu
2024-11-22 8:10 ` [PATCH V4] " Lizhi Xu
2024-11-22 11:50 ` Jan Kara
2024-11-23 1:09 ` [PATCH V5] " Lizhi Xu
2024-11-23 1:32 ` Al Viro
2024-11-24 4:43 ` [PATCH V6] fs/ntfs3: check if the inode is bad before instantiating dentry Lizhi Xu
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