From: Daniel Borkmann <daniel@iogearbox•net>
To: David Laight <David.Laight@ACULAB•COM>,
'Marcelo Ricardo Leitner' <marcelo.leitner@gmail•com>,
"netdev@vger•kernel.org" <netdev@vger•kernel.org>
Cc: "linux-sctp@vger•kernel.org" <linux-sctp@vger•kernel.org>,
Vlad Yasevich <vyasevich@gmail•com>,
Neil Horman <nhorman@tuxdriver•com>,
"linux-kernel@vger•kernel.org" <linux-kernel@vger•kernel.org>,
"davem@davemloft•net" <davem@davemloft•net>,
"syzkaller@googlegroups•com" <syzkaller@googlegroups•com>,
"dvyukov@google•com" <dvyukov@google•com>,
"kcc@google•com" <kcc@google•com>,
"glider@google•com" <glider@google•com>,
"sasha.levin@oracle•com" <sasha.levin@oracle•com>,
"edumazet@google•com" <edumazet@google•com>
Subject: Re: [PATCH] sctp: use GFP_USER for user-controlled kmalloc
Date: Tue, 01 Dec 2015 12:29:40 +0100 [thread overview]
Message-ID: <565D84A4.3080408@iogearbox.net> (raw)
In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D1CBDF85D@AcuExch.aculab.com>
On 12/01/2015 11:46 AM, David Laight wrote:
> From: Marcelo Ricardo Leitner
>> Sent: 30 November 2015 16:33
>> Dmitry Vyukov reported that the user could trigger a kernel warning by
>> using a large len value for getsockopt SCTP_GET_LOCAL_ADDRS, as that
>> value directly affects the value used as a kmalloc() parameter.
>>
>> This patch thus switches the allocation flags from all user-controllable
>> kmalloc size to GFP_USER to put some more restrictions on it and also
>> disables the warn, as they are not necessary.
>
> ISTM that the code should put some 'sanity limit' on that
> size before allocating the kernel buffer.
One could do that in addition, but this buffer has just a short lifetime
and by using GFP_USER hardwall restrictions apply already.
next prev parent reply other threads:[~2015-12-01 11:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CACT4Y+a_V5WQZNEnYkuA3Xc5qCWmLV3oScNeNiATZm-wW5eg3Q@mail.gmail.comc>
2015-11-30 16:32 ` [PATCH] sctp: use GFP_USER for user-controlled kmalloc Marcelo Ricardo Leitner
2015-12-01 10:46 ` David Laight
2015-12-01 11:29 ` Daniel Borkmann [this message]
2015-12-03 4:40 ` David Miller
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