From: Nicolas Pitre <npitre@baylibre.com>
To: Len Baker <len.baker@gmx.com>
Cc: Boris Brezillon <boris.brezillon@collabora.com>,
Kees Cook <keescook@chromium.org>,
linux-i3c@lists.infradead.org, linux-hardening@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] i3c/master/mipi-i3c-hci: Prefer struct_size over open coded arithmetic
Date: Mon, 6 Sep 2021 00:30:16 -0400 (EDT) [thread overview]
Message-ID: <65q16p1-7o22-pq77-38s8-9rr27p56s16n@onlyvoer.pbz> (raw)
In-Reply-To: <20210905144054.5124-1-len.baker@gmx.com>
On Sun, 5 Sep 2021, 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.
>
> 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>
Acked-by: Nicolas Pitre <npitre@baylibre.com>
> ---
> drivers/i3c/master/mipi-i3c-hci/dma.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c
> index af873a9be050..2990ac9eaade 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/dma.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/dma.c
> @@ -223,7 +223,7 @@ static int hci_dma_init(struct i3c_hci *hci)
> }
> if (nr_rings > XFER_RINGS)
> nr_rings = XFER_RINGS;
> - rings = kzalloc(sizeof(*rings) + nr_rings * sizeof(*rh), GFP_KERNEL);
> + rings = kzalloc(struct_size(rings, headers, nr_rings), GFP_KERNEL);
> if (!rings)
> return -ENOMEM;
> hci->io_data = rings;
> --
> 2.25.1
>
>
--
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next prev parent reply other threads:[~2021-09-06 4:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-05 14:40 [PATCH] i3c/master/mipi-i3c-hci: Prefer struct_size over open coded arithmetic Len Baker
2021-09-06 4:30 ` Nicolas Pitre [this message]
2021-09-13 17:39 ` Alexandre Belloni
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