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From: Leon Romanovsky <leon@kernel.org>
To: Len Baker <len.baker@gmx.com>
Cc: Selvin Xavier <selvin.xavier@broadcom.com>,
	Naresh Kumar PBS <nareshkumar.pbs@broadcom.com>,
	Doug Ledford <dledford@redhat.com>,
	Jason Gunthorpe <jgg@ziepe.ca>, Kees Cook <keescook@chromium.org>,
	linux-rdma@vger.kernel.org, linux-hardening@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] RDMA/bnxt_re: Prefer kcalloc over open coded arithmetic
Date: Sun, 5 Sep 2021 13:21:20 +0300	[thread overview]
Message-ID: <YTSaIMAlelivBGEv@unreal> (raw)
In-Reply-To: <20210905081812.17113-1-len.baker@gmx.com>

On Sun, Sep 05, 2021 at 10:18:12AM +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 sizes: both sides of the
> multiplication are constant values. However it is best to refactor this
> anyway, just to keep the open-coded math idiom out of code.
> 
> So, use the purpose specific kcalloc() function instead of the argument
> size * count in the kzalloc() function.
> 
> Also, remove the unnecessary initialization of the sqp_tbl variable
> since it is set a few lines later.
> 
> [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>
> ---
>  drivers/infiniband/hw/bnxt_re/ib_verbs.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 

Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>

  reply	other threads:[~2021-09-05 10:21 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-05  8:18 [PATCH] RDMA/bnxt_re: Prefer kcalloc over open coded arithmetic Len Baker
2021-09-05 10:21 ` Leon Romanovsky [this message]
2021-09-07 14:12   ` Selvin Xavier
2021-09-08 11:44 ` Jason Gunthorpe

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