From: Jan Kara <jack@suse.cz>
To: syzbot <syzbot+6fc7fb214625d82af7d1@syzkaller.appspotmail.com>
Cc: bingjingc@synology.com, cccheng@synology.com, jack@suse.cz,
linux-kernel@vger.kernel.org, pali@kernel.org,
robbieko@synology.com, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] KASAN: use-after-free Read in __isofs_iget
Date: Tue, 19 Oct 2021 11:16:39 +0200 [thread overview]
Message-ID: <20211019091639.GE3255@quack2.suse.cz> (raw)
In-Reply-To: <20211018104213.GD29715@quack2.suse.cz>
[-- Attachment #1: Type: text/plain, Size: 1531 bytes --]
On Mon 18-10-21 12:42:13, Jan Kara wrote:
> On Fri 15-10-21 17:35:19, syzbot wrote:
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit: d3134eb5de85 Add linux-next specific files for 20211011
> > git tree: linux-next
> > console output: https://syzkaller.appspot.com/x/log.txt?x=13f5fd98b00000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=b9662326d2be383b
> > dashboard link: https://syzkaller.appspot.com/bug?extid=6fc7fb214625d82af7d1
> > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15ca2e47300000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17869bd4b00000
> >
> > Bisection is inconclusive: the issue happens on the oldest tested release.
> >
> > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=10808570b00000
> > final oops: https://syzkaller.appspot.com/x/report.txt?x=12808570b00000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=14808570b00000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+6fc7fb214625d82af7d1@syzkaller.appspotmail.com
>
> Let's try this:
>
> #sys test 519d81956ee277b4419c723adfb154603c2565ba
Bah, I've messed up the tag. So let's try again:
#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 519d81956ee277b4419c723adfb154603c2565ba
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
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[-- Type: text/x-patch, Size: 939 bytes --]
From 5d06a4f26133fa8d45254febce7a46085e998ee7 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Mon, 18 Oct 2021 12:37:41 +0200
Subject: [PATCH] isofs: Fix out of bound access for corrupted isofs image
When isofs image is suitably corrupted isofs_read_inode() can read data
beyond the end of buffer. Sanity-check the directory entry length before
using it.
Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/isofs/inode.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c
index 678e2c51b855..0c6eacfcbeef 100644
--- a/fs/isofs/inode.c
+++ b/fs/isofs/inode.c
@@ -1322,6 +1322,8 @@ static int isofs_read_inode(struct inode *inode, int relocated)
de = (struct iso_directory_record *) (bh->b_data + offset);
de_len = *(unsigned char *) de;
+ if (de_len < sizeof(struct iso_directory_record))
+ goto fail;
if (offset + de_len > bufsize) {
int frag1 = bufsize - offset;
--
2.26.2
next prev parent reply other threads:[~2021-10-19 9:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-16 0:35 [syzbot] KASAN: use-after-free Read in __isofs_iget syzbot
2021-10-18 10:42 ` Jan Kara
2021-10-19 9:16 ` Jan Kara [this message]
2021-10-19 9:48 ` syzbot
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