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Date:   Sun, 12 Jul 2020 15:21:49 -0700
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Subject: Re: [PATCH] decompress_bunzip2: fix sizeof type in start_bunzip
To:     Tom Rix <trix@redhat.com>, alain@knaff.lu
CC:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
From:   hpa@zytor.com
Message-ID: <EE11D4F0-8DA4-4030-800E-516423293987@zytor.com>
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On July 12, 2020 8:12:43 AM PDT, Tom Rix <trix@redhat=2Ecom> wrote:
>
>On 7/12/20 6:09 AM, H=2E Peter Anvin wrote:
>> On 2020-07-12 05:59, trix@redhat=2Ecom wrote:
>>> From: Tom Rix <trix@redhat=2Ecom>
>>>
>>> clang static analysis flags this error
>>>
>>> lib/decompress_bunzip2=2Ec:671:13: warning: Result of 'malloc' is
>converted
>>>   to a pointer of type 'unsigned int', which is incompatible with
>sizeof
>>>   operand type 'int' [unix=2EMallocSizeof]
>>>         bd->dbuf =3D 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=2E
>>
>> 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=2E For sizeof(int) !=3D
>sizeof(unsigned
>> int) is beyond bizarre, no matter how stupid the platform=2E
>
>Using the actual type is more correct that using a type of the same
>size=2E
>
>trix
>
>> 	-hpa
>>

"More correct?" All it is is more verbose=2E

Using the sizeof of the actual object at least adds some actual safety=2E
--=20
Sent from my Android device with K-9 Mail=2E Please excuse my brevity=2E