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From: Takashi Iwai <tiwai@suse.de>
To: Len Baker <len.baker@gmx.com>
Cc: Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
	gushengxian <gushengxian@yulong.com>,
	Kees Cook <keescook@chromium.org>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	alsa-devel@alsa-project.org, linux-hardening@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ALSA: usx2y: Prefer struct_size over open coded arithmetic
Date: Tue, 21 Sep 2021 18:41:24 +0200	[thread overview]
Message-ID: <s5h35px98zv.wl-tiwai@suse.de> (raw)
In-Reply-To: <20210919133727.44694-1-len.baker@gmx.com>

On Sun, 19 Sep 2021 15:37:27 +0200,
Len Baker wrote:
> 
> As noted in the "Deprecated Interfaces, Language Features, Attributes,
> and Conventions" documentation [1], size calculations (especially
> multiplication) should not be performed in memory allocator (or similar)
> function arguments due to the risk of them overflowing. This could lead
> to values wrapping around and a smaller allocation being made than the
> caller was expecting. Using those allocations could lead to linear
> overflows of heap memory and other misbehaviors.
> 
> In this case this is not actually dynamic size: all the operands
> involved in the calculation are constant values. However it is better to
> refactor this anyway, just to keep the open-coded math idiom out of
> code.
> 
> So, use the struct_size() helper to do the arithmetic instead of the
> argument "size + size * count" in the kzalloc() function.
> 
> Also, take the opportunity to refactor the declaration variables to make
> it more easy to read.
> 
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments
> 
> Signed-off-by: Len Baker <len.baker@gmx.com>

Thanks, applied.


Takashi

      reply	other threads:[~2021-09-21 16:41 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-19 13:37 [PATCH] ALSA: usx2y: Prefer struct_size over open coded arithmetic Len Baker
2021-09-21 16:41 ` Takashi Iwai [this message]

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