linux-hardening - Re: [PATCH] docs: deprecated.rst: Clarify open-coded arithmetic with literals

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Message-ID: <9a338127-0b17-fa9e-96b6-578193ce96f4@embeddedor.com>
Date:   Fri, 27 Aug 2021 14:22:58 -0500
From:   "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To:     Joe Perches <joe@...ches.com>, Len Baker <len.baker@....com>,
        Jonathan Corbet <corbet@....net>,
        Kees Cook <keescook@...omium.org>
Cc:     "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-hardening@...r.kernel.org
Subject: Re: [PATCH] docs: deprecated.rst: Clarify open-coded arithmetic with
 literals



On 8/27/21 14:06, Joe Perches wrote:
> On Fri, 2021-08-27 at 19:12 +0200, Len Baker wrote:
>> Although using literals for size calculation in allocator arguments may
>> be harmless due to compiler warnings in case of overflows, it is better
>> to refactor the code to avoid the use of open-coded math idiom.
>>
>> So, clarify the preferred way in these cases.
> []
>> diff --git a/Documentation/process/deprecated.rst b/Documentation/process/deprecated.rst
> []
>> @@ -60,7 +60,8 @@ smaller allocation being made than the caller was expecting. Using those
>>  allocations could lead to linear overflows of heap memory and other
>>  misbehaviors. (One exception to this is literal values where the compiler
>>  can warn if they might overflow. Though using literals for arguments as
>> -suggested below is also harmless.)
>> +suggested below is also harmless. So, the preferred way in these cases is
>> +to refactor the code to keep the open-coded math idiom out.)
> 
> wordsmithing trivia:
> 
> 'keep <foo> out' is difficult to parse as 'keep' is generally a positive
> word but its meaning is later reversed with out.
> 
> 'avoid <foo>' maybe be better phrasing.

+1

--
Gustavo