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References: <20200317061522.12685-1-rayagonda.kokatanur@broadcom.com> <20200317061522.12685-3-rayagonda.kokatanur@broadcom.com>
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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Tue, 17 Mar 2020 10:36:40 -0700
Message-ID: <CAPcyv4j1BJStqSZvbNdjHs0RoSWWtk06ieQAXOUwJCjP8mqBLQ@mail.gmail.com>
Subject: Re: [PATCH v1 2/2] async_tx: fix possible negative array indexing
To:     Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>
Cc:     Herbert Xu <herbert@gondor.apana.org.au>,
        "David S . Miller" <davem@davemloft.net>,
        Allison Randal <allison@lohutok.net>,
        Kate Stewart <kstewart@linuxfoundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-crypto <linux-crypto@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Mon, Mar 16, 2020 at 11:16 PM Rayagonda Kokatanur
<rayagonda.kokatanur@broadcom.com> wrote:
>
> Fix possible negative array index read in __2data_recov_5() function.
>
> Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>
> ---
>  crypto/async_tx/async_raid6_recov.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/crypto/async_tx/async_raid6_recov.c b/crypto/async_tx/async_raid6_recov.c
> index 33f2a8f8c9f4..9cd016cb2d09 100644
> --- a/crypto/async_tx/async_raid6_recov.c
> +++ b/crypto/async_tx/async_raid6_recov.c
> @@ -206,7 +206,7 @@ __2data_recov_5(int disks, size_t bytes, int faila, int failb,
>                 good_srcs++;
>         }
>
> -       if (good_srcs > 1)
> +       if ((good_srcs > 1) || (good < 0))
>                 return NULL;

Read the code again, I don't see how this can happen.