linux-kernel - Re: [PATCH] kernel/irq/proc.c: set MAX_NAMELEN 11 instead of 10 which express the maximize size of "%d" or "%u".

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: <52505048.8000604@nod.at>
Date:	Sat, 05 Oct 2013 19:45:44 +0200
From:	Richard Weinberger <richard@....at>
To:	Chen Gang <gang.chen@...anux.com>
CC:	Richard Weinberger <richard.weinberger@...il.com>,
	Joe Perches <joe@...ches.com>,
	Al Viro <viro@...iv.linux.org.uk>,
	Thomas Gleixner <tglx@...utronix.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] kernel/irq/proc.c: set MAX_NAMELEN 11 instead of 10 which
 express the maximize size of "%d" or "%u".

Am 05.10.2013 19:06, schrieb Chen Gang:
> On 10/06/2013 12:50 AM, Chen Gang wrote:
>> On 10/06/2013 12:08 AM, Richard Weinberger wrote:
>>> On Sat, Oct 5, 2013 at 5:46 PM, Chen Gang <gang.chen@...anux.com> wrote:
>>>> On 10/05/2013 11:41 PM, Joe Perches wrote:
>>>>> On Sat, 2013-10-05 at 23:19 +0800, Chen Gang wrote:
>>>>>> Theoretically, the maximize size of "%d" or "%u" is 11 (10 + '\0'), so
>>>>>> need set MAX_NAMELEN 11 instead of 10.
>>>>>
>>>>> %d can be negative.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>> Oh, really, it is incorrect. Al Viro succeeds once.  :-(
>>>>
>>>> And I should send patch v2 for it.
>>>
>>> irq is in both register_irq_proc() and unregister_irq_proc() an unsigned int.
>>> Therefore %d makes not really sense. Both should use %u.
>>> IMHO sprintf() should also get replaced by snprintf() but that's a
>>> matter of taste.
>>>
> 
> Oh, commonly, snprintf() are used for the string which can be truncated,
> and can not be used for the string which contents must not be truncated.
> 
> In our case, the name string must be not truncated (or may not unique,
> theoretically), so we have to still use sprintf().

Of course you would have to check the return value of snprintf() to detect
a truncation and abort...

Thanks,
//richard

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/