From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Erick Archer <erick.archer@outlook.com>
Cc: Kees Cook <keescook@chromium.org>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH] Input: ff-core - prefer struct_size over open coded arithmetic
Date: Tue, 30 Apr 2024 14:04:59 -0700 [thread overview]
Message-ID: <ZjFc--tMio1wmBpf@google.com> (raw)
In-Reply-To: <AS8PR02MB72371E646714BAE2E51A6A378B152@AS8PR02MB7237.eurprd02.prod.outlook.com>
On Sat, Apr 27, 2024 at 05:05:56PM +0200, Erick Archer wrote:
> This is an effort to get rid of all multiplications from allocation
> functions in order to prevent integer overflows [1][2].
>
> As the "ff" variable is a pointer to "struct ff_device" and this
> structure ends in a flexible array:
>
> struct ff_device {
> [...]
> struct file *effect_owners[] __counted_by(max_effects);
> };
>
> the preferred way in the kernel is to use the struct_size() helper to
> do the arithmetic instead of the calculation "size + count * size" in
> the kzalloc() function.
>
> The struct_size() helper returns SIZE_MAX on overflow. So, refactor
> the comparison to take advantage of this.
>
> This way, the code is more readable and safer.
>
> This code was detected with the help of Coccinelle, and audited and
> modified manually.
>
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
> Link: https://github.com/KSPP/linux/issues/160 [2]
> Signed-off-by: Erick Archer <erick.archer@outlook.com>
Applied, thank you.
--
Dmitry
prev parent reply other threads:[~2024-04-30 21:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-27 15:05 [PATCH] Input: ff-core - prefer struct_size over open coded arithmetic Erick Archer
2024-04-29 17:38 ` Kees Cook
2024-04-30 21:04 ` Dmitry Torokhov [this message]
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