linux-kernel - Re: [PATCH] Fix read buffer overflow in delta-ipc

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20180104001933.3jcawm7eqrfgmvr7@two.firstfloor.org>
Date:   Wed, 3 Jan 2018 16:19:34 -0800
From:   Andi Kleen <andi@...stfloor.org>
To:     Hugues FRUCHET <hugues.fruchet@...com>
Cc:     Andi Kleen <andi@...stfloor.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        Andi Kleen <ak@...ux.intel.com>,
        "mchehab@...pensource.com" <mchehab@...pensource.com>
Subject: Re: [PATCH] Fix read buffer overflow in delta-ipc

On Wed, Jan 03, 2018 at 09:40:04AM +0000, Hugues FRUCHET wrote:
> Hi Andi,
> Thanks for the patch but I would suggest to use strlcpy instead, this 
> will guard msg.name overwriting and add the NULL termination in case
> of truncation:
> -	memcpy(msg.name, name, sizeof(msg.name));
> -	msg.name[sizeof(msg.name) - 1] = 0;
> +	strlcpy(msg.name, name, sizeof(msg.name));

I'm not an expert on your setup, but it seems strlcpy would leak some
uninitialized stack data over your ipc mechanism. strclpy doesn't pad the
data. If the IPC is a security boundary that would be a security bug.

So I think the original patch is better than strlcpy.

-Andi