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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Jozsef Kadlecsik <kadlec@netfilter.org>
Cc: coreteam@netfilter.org, David Miller <davem@davemloft.net>,
	Marco Elver <elver@google.com>, Florian Westphal <fw@strlen.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Enrico Weigelt, metux IT consult" <info@metux.net>,
	jeremy@azazel.net, Kate Stewart <kstewart@linuxfoundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Netdev <netdev@vger.kernel.org>,
	netfilter-devel@vger.kernel.org,
	Pablo Neira Ayuso <pablo@netfilter.org>,
	syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: KASAN: slab-out-of-bounds Read in bitmap_ip_add
Date: Fri, 31 Jan 2020 12:57:23 -0800	[thread overview]
Message-ID: <CAHk-=wgNo-3FuNWSj+pRqJEG3phVnpcEi+NNq7f_VMWeTugFDA@mail.gmail.com> (raw)
In-Reply-To: <000000000000ed3a48059d17277e@google.com>

On Sun, Jan 26, 2020 at 8:01 PM syzbot
<syzbot+f3e96783d74ee8ea9aa3@syzkaller.appspotmail.com> wrote:
>
> syzbot has bisected this bug to:

Ok, the bisection is obviously bogus - it just points to where the
KASAN support was added to _notice_ the problem.

But is somebody looking at the actual KASAN report itself?

  https://syzkaller.appspot.com/bug?extid=f3e96783d74ee8ea9aa3

It does look like nfnetlink_rcv_msg() ends up looking at a bit:

 bitmap_ip_do_add net/netfilter/ipset/ip_set_bitmap_ip.c:83 [inline]
 bitmap_ip_add+0xef/0xe60 net/netfilter/ipset/ip_set_bitmap_gen.h:136
 bitmap_ip_uadt+0x73e/0xa10 net/netfilter/ipset/ip_set_bitmap_ip.c:186
 call_ad+0x1a0/0x5a0 net/netfilter/ipset/ip_set_core.c:1716
 ip_set_ad.isra.0+0x572/0xb20 net/netfilter/ipset/ip_set_core.c:1804
 ip_set_uadd+0x37/0x50 net/netfilter/ipset/ip_set_core.c:1829
 nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229

that is past the allocation:

 ip_set_alloc+0x38/0x5e net/netfilter/ipset/ip_set_core.c:255
 init_map_ip net/netfilter/ipset/ip_set_bitmap_ip.c:223 [inline]
 bitmap_ip_create+0x6ec/0xc20 net/netfilter/ipset/ip_set_bitmap_ip.c:327
 ip_set_create+0x6f1/0x1500 net/netfilter/ipset/ip_set_core.c:1111
 nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229

Maybe this has already been fixed, but I'm just trying to follow-up on
the syzbot report..

           Linus

  reply	other threads:[~2020-01-31 20:57 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-19  2:07 KASAN: slab-out-of-bounds Read in bitmap_ip_add syzbot
2020-01-27  4:01 ` syzbot
2020-01-31 20:57   ` Linus Torvalds [this message]
2020-01-31 21:02     ` Cong Wang
2020-01-31 21:06       ` Linus Torvalds
2020-03-22 18:02 ` syzbot

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