linux-kernel - Re: [PATCH] net: sched: Fix memory exposure from short TCA_U32

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAGXu5jJD++hegH4j0ajZNejg8mgcHjqVyjveWj9BFaXwRCV_dQ@mail.gmail.com>
Date:   Mon, 27 Aug 2018 07:08:22 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Jamal Hadi Salim <jhs@...atatu.com>
Cc:     Al Viro <viro@...iv.linux.org.uk>,
        LKML <linux-kernel@...r.kernel.org>,
        Cong Wang <xiyou.wangcong@...il.com>,
        Jiri Pirko <jiri@...nulli.us>,
        "David S. Miller" <davem@...emloft.net>,
        Network Development <netdev@...r.kernel.org>
Subject: Re: [PATCH] net: sched: Fix memory exposure from short TCA_U32_SEL

On Mon, Aug 27, 2018 at 4:46 AM, Jamal Hadi Salim <jhs@...atatu.com> wrote:
> On 2018-08-26 5:56 p.m., Kees Cook wrote:
>>
>> On Sun, Aug 26, 2018 at 10:30 AM, Jamal Hadi Salim <jhs@...atatu.com>
>> wrote:
>>>
>>> We should add an nla_policy later.
>>
>>
>> What's the right way to do that for cases like this?
>
>
> Meant something like attached which you alluded-to in your comments
> would give an upper bound (Max allowed keys is 128).

The problem is that policy doesn't parse the contents: "nkeys"
determines the size, so we have to both validate minimum size (to be
sure the location of "nkeys" is valid) and check that the size is at
least nkeys * struct long. I don't think there is a way to do this
with the existing policy language.

-Kees

-- 
Kees Cook
Pixel Security