efi_loader: pkcs7_parse_message() returns error pointer

From: Heinrich Schuchardt <xypron.glpk@gmx.de>
To: u-boot@lists.denx.de
Subject: efi_loader: pkcs7_parse_message() returns error pointer
Date: Thu, 7 May 2020 18:02:31 +0200	[thread overview]
Message-ID: <99ce623b-fd71-a4ec-13ae-7ff750382d2b@gmx.de> (raw)
In-Reply-To: <20200507001714.GA6487@nox.fritz.box>

On 07.05.20 02:17, Patrick Wildt wrote:
> Since pkcs7_parse_message() returns an error pointer, we must not
> check for NULL.  We have to explicitly set msg to NULL in the error
> case, otherwise the call to pkcs7_free_message() on the goto err
> path will assume it's a valid object.
>
> Signed-off-by: Patrick Wildt <patrick@blueri.se>
>
> diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c
> index 5a9a6424cc..43a53d3dd1 100644
> --- a/lib/efi_loader/efi_image_loader.c
> +++ b/lib/efi_loader/efi_image_loader.c
> @@ -538,8 +538,9 @@ static bool efi_image_authenticate(void *efi, size_t efi_size)
>  		}
>  		msg = pkcs7_parse_message((void *)wincert + sizeof(*wincert),
>  					  wincert->dwLength - sizeof(*wincert));
> -		if (!msg) {
> +		if (IS_ERR(msg)) {

Compiling with sandbox_defconfig results in:

lib/efi_loader/efi_image_loader.c: In function ?efi_image_authenticate?:
lib/efi_loader/efi_image_loader.c:541:7: warning: implicit declaration
of function ?IS_ERR? [-Wimplicit-function-declaration]
  541 |   if (IS_ERR(msg)) {
      |       ^~~~~~

I will add the missing #include <linux/err.h> when merging.

Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

>  			debug("Parsing image's signature failed\n");
> +			msg = NULL;
>  			goto err;
>  		}
>
>