linux-kernel - Re: [PATCH] decompress_bunzip2: fix sizeof type in start

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: <EE11D4F0-8DA4-4030-800E-516423293987@zytor.com>
Date:   Sun, 12 Jul 2020 15:21:49 -0700
From:   hpa@...or.com
To:     Tom Rix <trix@...hat.com>, alain@...ff.lu
CC:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH] decompress_bunzip2: fix sizeof type in start_bunzip

On July 12, 2020 8:12:43 AM PDT, Tom Rix <trix@...hat.com> wrote:
>
>On 7/12/20 6:09 AM, H. Peter Anvin wrote:
>> On 2020-07-12 05:59, trix@...hat.com wrote:
>>> From: Tom Rix <trix@...hat.com>
>>>
>>> clang static analysis flags this error
>>>
>>> lib/decompress_bunzip2.c:671:13: warning: Result of 'malloc' is
>converted
>>>   to a pointer of type 'unsigned int', which is incompatible with
>sizeof
>>>   operand type 'int' [unix.MallocSizeof]
>>>         bd->dbuf = large_malloc(bd->dbufSize * sizeof(int));
>>>                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>
>>> Reviewing the bunzip_data structure, the element dbuf is type
>>>
>>> 	/* Intermediate buffer and its size (in bytes) */
>>> 	unsigned int *dbuf, dbufSize;
>>>
>>> So change the type in sizeof to 'unsigned int'
>>>
>> You must be kidding.
>>
>> If you want to change it, change it to sizeof(bd->dbuf) instead, but
>this flag
>> is at least in my opinion a total joke. For sizeof(int) !=
>sizeof(unsigned
>> int) is beyond bizarre, no matter how stupid the platform.
>
>Using the actual type is more correct that using a type of the same
>size.
>
>trix
>
>> 	-hpa
>>

"More correct?" All it is is more verbose.

Using the sizeof of the actual object at least adds some actual safety.
-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.