linux-kernel - Re: [PATCH] core: Catch overflows in do

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: <CAFLxGvzrEQGE8+QAFCQL=z2hwe578pBdWOu4B+DkJDjxkM0=hw@mail.gmail.com>
Date:	Tue, 8 Oct 2013 18:45:21 +0200
From:	Richard Weinberger <richard.weinberger@...il.com>
To:	Joe Perches <joe@...ches.com>
Cc:	Anatol Pomozov <anatol.pomozov@...il.com>,
	LKML <linux-kernel@...r.kernel.org>, rdunlap@...radead.org
Subject: Re: [PATCH] core: Catch overflows in do_div() function

On Tue, Oct 8, 2013 at 6:18 PM, Joe Perches <joe@...ches.com> wrote:
> On Tue, 2013-10-08 at 09:10 -0700, Anatol Pomozov wrote:
>> If second parameter passed to this function was 64 then it silently
>> truncates to 32 bits. Catch such situation.
> []
>> diff --git a/include/asm-generic/div64.h b/include/asm-generic/div64.h
> []
>> @@ -25,6 +26,7 @@
>>  # define do_div(n,base) ({                                   \
>>       uint32_t __base = (base);                               \
>>       uint32_t __rem;                                         \
>> +     BUG_ON(sizeof(base) > 4 && base >= (1UL<<32));          \
>
> I think this would be better as a BUILD_BUG_ON

No. BUILD_BUG_ON works only for constants.

Anatol, have you tested whether your change increases the kernel size?

-- 
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/