linux-hardening - Re: [PATCH] RDMA/bnxt_re: Prefer kcalloc over open coded arithmetic

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Message-ID: <CA+sbYW0YMFc-ohPUWu=a-NNasbM+Yk4dH5v-yYZuAjmZcAJysg@mail.gmail.com>
Date:   Tue, 7 Sep 2021 19:42:03 +0530
From:   Selvin Xavier <selvin.xavier@...adcom.com>
To:     Leon Romanovsky <leon@...nel.org>
Cc:     Len Baker <len.baker@....com>,
        Naresh Kumar PBS <nareshkumar.pbs@...adcom.com>,
        Doug Ledford <dledford@...hat.com>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Kees Cook <keescook@...omium.org>, linux-rdma@...r.kernel.org,
        linux-hardening@...r.kernel.org,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] RDMA/bnxt_re: Prefer kcalloc over open coded arithmetic

On Sun, Sep 5, 2021 at 3:51 PM Leon Romanovsky <leon@...nel.org> wrote:
>
> 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@....com>
> > ---
> >  drivers/infiniband/hw/bnxt_re/ib_verbs.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
>
> Thanks,
> Reviewed-by: Leon Romanovsky <leonro@...dia.com>
Acked-by: Selvin Xavier <selvin.xavier@...adcom.com>

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