From: Andrey Ryabinin <ryabinin.a.a@gmail.com>
To: Sasha Levin <sasha.levin@oracle.com>
Cc: Andrey Ryabinin <a.ryabinin@samsung.com>,
"David S. Miller" <davem@davemloft.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Dave Jones <davej@redhat.com>,
Hannes Frederic Sowa <hannes@stressinduktion.org>,
Eric Dumazet <edumazet@google.com>
Subject: Re: net: socket: NULL ptr deref in sendmsg
Date: Sat, 26 Jul 2014 19:40:51 +0400 [thread overview]
Message-ID: <CAPAsAGwxk7qO7j8-fRWNGuoFKaNoadwtHxrps41hK9jH5=KTQA@mail.gmail.com> (raw)
In-Reply-To: <53D2C38A.70601@oracle.com>
2014-07-26 0:52 GMT+04:00 Sasha Levin <sasha.levin@oracle.com>:
> On 07/25/2014 11:23 AM, Andrey Ryabinin wrote:
>> After this report there was no usual "Unable to handle kernel NULL pointer dereference"
>> and this gave me a clue that address 0 is mapped and contains valid socket address structure in it.
>
> Interesting. Does it mean that all network protocols that check it for being NULL instead of checking
> the length are incorrect?
>
I think they are correct. After verify_iovec() we should have either
both msg->msg_name == 0 and msg->msg_namelen == 0,
or both != 0 (and msg_name should be a kernel address).
That bug allows to leave verify_iovec() with msg_namelen > 0 and
msg_name == NULL, causing troubles for protocols checking only
msg_namelen.
> (such as:)
>
> if (msg->msg_name) {
> DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
>
> [...]
>
>
> Thanks,
> Sasha
>
--
Best regards,
Andrey Ryabinin
next prev parent reply other threads:[~2014-07-26 15:40 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-13 21:50 net: socket: NULL ptr deref in sendmsg Sasha Levin
2014-07-14 22:08 ` David Miller
2014-07-24 16:05 ` Sasha Levin
2014-07-25 15:23 ` Andrey Ryabinin
2014-07-25 18:27 ` Eric Dumazet
2014-07-25 20:52 ` Sasha Levin
2014-07-25 22:15 ` Hannes Frederic Sowa
2014-07-26 15:40 ` Andrey Ryabinin [this message]
2014-07-25 22:15 ` Hannes Frederic Sowa
2014-07-26 15:48 ` Andrey Ryabinin
2014-07-26 15:54 ` Hannes Frederic Sowa
2014-07-26 17:26 ` [PATCH] net: sendmsg: fix NULL pointer dereference Andrey Ryabinin
2014-07-28 9:50 ` Hannes Frederic Sowa
2014-07-29 19:21 ` David Miller
2014-07-29 0:19 ` net: socket: NULL ptr deref in sendmsg David Miller
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