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From: Matthew Wilcox <willy@infradead.org>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org,
	Tigran Aivazian <aivazian.tigran@gmail.com>,
	syzbot <syzbot+71c6b5d68e91149fc8a4@syzkaller.appspotmail.com>
Subject: Re: [PATCH] bfs: add sanity check at bfs_fill_super().
Date: Wed, 9 May 2018 17:53:21 -0700	[thread overview]
Message-ID: <20180510005321.GA4903@bombadil.infradead.org> (raw)
In-Reply-To: <1525862104-3407-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp>

On Wed, May 09, 2018 at 07:35:04PM +0900, Tetsuo Handa wrote:
> syzbot is reporting too large memory allocation at bfs_fill_super() [1].
> Since file system image is corrupted such that bfs_sb->s_start == 0,
> bfs_fill_super() is trying to allocate 8MB of continuous memory. Fix this
> by adding a sanity check on bfs_sb->s_start, __GFP_NOWARN and printf().
> 
> [1] https://syzkaller.appspot.com/bug?id=16a87c236b951351374a84c8a32f40edbc034e96

Looking at that C reproducer, it looks like it's trying to fuzz filesystem
images:

https://syzkaller.appspot.com/text?tag=ReproC&x=15b834a7800000

Do we really want this?  I was under the impression that we simply do not
care about attackers who have control of the media, and having syzbot
generate thousands of bugs that nobody will work on is not a good use
of anybody's time.

      parent reply	other threads:[~2018-05-10  0:53 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-09 10:35 [PATCH] bfs: add sanity check at bfs_fill_super() Tetsuo Handa
2018-05-09 23:06 ` Andrew Morton
     [not found]   ` <201805092346.w49NkINl045657@www262.sakura.ne.jp>
2018-05-09 23:53     ` Andrew Morton
2018-06-13 13:33       ` Tetsuo Handa
2018-06-13 13:49         ` Tigran Aivazian
2018-06-13 16:00           ` Dmitry Vyukov
2018-06-14 12:23             ` Tigran Aivazian
2018-06-14 12:38               ` Dmitry Vyukov
2018-06-14 13:05                 ` Tigran Aivazian
2018-06-14 13:12                   ` Dmitry Vyukov
2018-06-14 13:28                   ` Tetsuo Handa
2018-06-14 15:13                     ` Tigran Aivazian
2018-06-14 16:15                       ` Tigran Aivazian
2018-06-14 19:00                         ` Tigran Aivazian
2018-06-14 22:18                           ` Tetsuo Handa
2018-06-15 10:45                             ` Tigran Aivazian
2018-06-13 22:09           ` Tetsuo Handa
2018-06-14  7:38             ` Tigran Aivazian
2018-06-14 10:45               ` Tetsuo Handa
2018-06-14 12:11                 ` Tigran Aivazian
2018-05-10  0:53 ` Matthew Wilcox [this message]

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