From: Ulf Hansson <ulf.hansson@linaro.org>
To: Len Baker <len.baker@gmx.com>
Cc: Maxim Levitsky <maximlevitsky@gmail.com>,
Alex Dubov <oakad@yahoo.com>, Kees Cook <keescook@chromium.org>,
Tom Rix <trix@redhat.com>,
linux-hardening@vger.kernel.org,
linux-mmc <linux-mmc@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] memstick: jmb38x_ms: Prefer struct_size over open coded arithmetic
Date: Tue, 14 Sep 2021 13:23:55 +0200 [thread overview]
Message-ID: <CAPDyKFrmSOWF4CsRApq58PVtp2XDfwsBFCYs4vHDDatQHQAA+g@mail.gmail.com> (raw)
In-Reply-To: <20210911131933.2089-1-len.baker@gmx.com>
On Sat, 11 Sept 2021 at 15:22, Len Baker <len.baker@gmx.com> 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.
>
> So, use the struct_size() helper to do the arithmetic instead of the
> argument "size + count * size" in the kzalloc() function.
>
> [1] https://www.kernel.org/doc/html/v5.14/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments
>
> Signed-off-by: Len Baker <len.baker@gmx.com>
Applied for next, thanks!
Kind regards
Uffe
> ---
> drivers/memstick/host/jmb38x_ms.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/memstick/host/jmb38x_ms.c b/drivers/memstick/host/jmb38x_ms.c
> index f9a93b0565e1..a7a0f0caea15 100644
> --- a/drivers/memstick/host/jmb38x_ms.c
> +++ b/drivers/memstick/host/jmb38x_ms.c
> @@ -927,8 +927,7 @@ static int jmb38x_ms_probe(struct pci_dev *pdev,
> goto err_out_int;
> }
>
> - jm = kzalloc(sizeof(struct jmb38x_ms)
> - + cnt * sizeof(struct memstick_host *), GFP_KERNEL);
> + jm = kzalloc(struct_size(jm, hosts, cnt), GFP_KERNEL);
> if (!jm) {
> rc = -ENOMEM;
> goto err_out_int;
> --
> 2.25.1
>
prev parent reply other threads:[~2021-09-14 11:24 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-11 13:19 [PATCH] memstick: jmb38x_ms: Prefer struct_size over open coded arithmetic Len Baker
2021-09-14 11:23 ` Ulf Hansson [this message]
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