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

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Message-ID: <9af191c2-0f2c-7637-433a-b557a07590ca@redhat.com>
Date:   Sun, 12 Jul 2020 08:12:43 -0700
From:   Tom Rix <trix@...hat.com>
To:     "H. Peter Anvin" <hpa@...or.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 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
>