From: Eric Dumazet <eric.dumazet@gmail.com>
To: Cong Wang <xiyou.wangcong@gmail.com>,
Eric Dumazet <eric.dumazet@gmail.com>
Cc: syzbot <syzbot+5af9a90dad568aa9f611@syzkaller.appspotmail.com>,
David Miller <davem@davemloft.net>,
Jamal Hadi Salim <jhs@mojatatu.com>,
Jiri Pirko <jiri@resnulli.us>,
LKML <linux-kernel@vger.kernel.org>,
Linux Kernel Network Developers <netdev@vger.kernel.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: Re: KASAN: slab-out-of-bounds Read in __nla_put_nohdr
Date: Wed, 22 Jan 2020 12:33:17 -0800 [thread overview]
Message-ID: <7056f971-8fae-ce88-7e9a-7983e4f57bb2@gmail.com> (raw)
In-Reply-To: <CAM_iQpXqh1ucVST199c72V22zLPujZy-54p=c5ar=Q9bWNq7OA@mail.gmail.com>
On 1/22/20 12:27 PM, Cong Wang wrote:
> On Tue, Jan 21, 2020 at 11:55 AM Eric Dumazet <eric.dumazet@gmail.com> wrote:
>> em_nbyte_change() sets
>> em->datalen = sizeof(*nbyte) + nbyte->len;
>>
>> But later tcf_em_validate() overwrites em->datalen with the user provide value (em->datalen = data_len; )
>> which can be bigger than the allocated (kmemdup) space in em_nbyte_change()
>>
>> Should net/sched/em_nbyte.c() provide a dump() handler to avoid this issue ?
>
> I think for those who implement ->change() we should leave
> ->datalen untouched to respect their choices. I don't see why
> we have to set it twice.
>
>
Agreed, but we need to audit them to make sure all of them are setting ->datalen
next prev parent reply other threads:[~2020-01-22 20:33 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-21 19:47 KASAN: slab-out-of-bounds Read in __nla_put_nohdr syzbot
2020-01-21 19:55 ` Eric Dumazet
2020-01-22 20:27 ` Cong Wang
2020-01-22 20:33 ` Eric Dumazet [this message]
2020-01-22 22:09 ` Cong Wang
2020-01-23 7:13 ` Dan Carpenter
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