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References: <20211228020611.6582-1-hbh25y@gmail.com>
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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Tue, 28 Dec 2021 09:39:49 +0100
Message-ID: <CAMuHMdXYuH6kgWCPjQhmd6Xi2N=oiyCSoE8U4NMg3tOrJ9bwDw@mail.gmail.com>
Subject: Re: [PATCH v2] m68k/kernel: array out of bound access in process_uboot_commandline
To:     Hangyu Hua <hbh25y@gmail.com>
Cc:     linux-m68k <linux-m68k@lists.linux-m68k.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Greg Ungerer <gerg@linux-m68k.org>
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CC greg

On Tue, Dec 28, 2021 at 3:06 AM Hangyu Hua <hbh25y@gmail.com> wrote:
>
> When the size of commandp >= size, array out of bound write occurs because
> len == 0.
>
> Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
> ---
>  arch/m68k/kernel/uboot.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/m68k/kernel/uboot.c b/arch/m68k/kernel/uboot.c
> index 928dbd33fc4a..63eaf3c3ddcd 100644
> --- a/arch/m68k/kernel/uboot.c
> +++ b/arch/m68k/kernel/uboot.c
> @@ -101,5 +101,6 @@ __init void process_uboot_commandline(char *commandp, int size)
>         }
>
>         parse_uboot_commandline(commandp, len);
> -       commandp[len - 1] = 0;
> +       if (len > 0)
> +               commandp[len - 1] = 0;
>  }
> --
> 2.25.1