linux-kernel - Re: [PATCH 1/1] efi/libstub: setup_graphics() do not return random data

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Message-ID: <CAMj1kXHo+utD4Y2BT0kcefEtYUKZsEWvqgzMNcJy0GE3Cw3jGA@mail.gmail.com>
Date:   Mon, 27 Apr 2020 08:52:29 +0200
From:   Ard Biesheuvel <ardb@...nel.org>
To:     Heinrich Schuchardt <xypron.glpk@....de>
Cc:     Ingo Molnar <mingo@...nel.org>,
        linux-efi <linux-efi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/1] efi/libstub: setup_graphics() do not return random data

On Sun, 26 Apr 2020 at 21:49, Heinrich Schuchardt <xypron.glpk@....de> wrote:
>
> Currently setup_graphics() ignores the return value of efi_setup_gop(). As
> AllocatePool() does not zero out memory the screen information table will
> contain random data in this case.
>
> We should free the screen information table if efi_setup_gop() returns an
> error code.
>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk@....de>

Thanks Heinrich

I will take this as a fix


> ---
>  drivers/firmware/efi/libstub/efi-stub.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/efi/libstub/efi-stub.c b/drivers/firmware/efi/libstub/efi-stub.c
> index ee225b323687..60377e5ceab3 100644
> --- a/drivers/firmware/efi/libstub/efi-stub.c
> +++ b/drivers/firmware/efi/libstub/efi-stub.c
> @@ -55,7 +55,11 @@ static struct screen_info *setup_graphics(void)
>                 si = alloc_screen_info();
>                 if (!si)
>                         return NULL;
> -               efi_setup_gop(si, &gop_proto, size);
> +               status = efi_setup_gop(si, &gop_proto, size);
> +               if (status != EFI_SUCCESS) {
> +                       free_screen_info(si);
> +                       return NULL;
> +               }
>         }
>         return si;
>  }
> --
> 2.26.2
>