[PATCH v2 1/2] cmd: mvebu/bubt: Check for A38x image data checksum

[Stefan Roese]

Hi Pali,

On 09.08.22 21:42, Pali Rohár wrote:
> Currently for A38x image is checked only header checksum.
> So check also for image data checksum to prevent flashing broken image.
> 
> Signed-off-by: Pali Rohár <pali at kernel.org>
> 
> ---
> Changes in v2:
> * Compile fix (move code chunk from patch 2/2 to 1/2)
> ---
>   cmd/mvebu/bubt.c | 45 ++++++++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 44 insertions(+), 1 deletion(-)
> 
> diff --git a/cmd/mvebu/bubt.c b/cmd/mvebu/bubt.c
> index 2136af64163c..3b6ffb7ffd1f 100644
> --- a/cmd/mvebu/bubt.c
> +++ b/cmd/mvebu/bubt.c
> @@ -688,9 +688,24 @@ static uint8_t image_checksum8(const void *start, size_t len)
>   	return csum;
>   }
>   
> +static uint32_t image_checksum32(const void *start, size_t len)
> +{
> +	u32 csum = 0;
> +	const u32 *p = start;
> +
> +	while (len) {
> +		csum += *p;
> +		++p;
> +		len -= sizeof(u32);
> +	}
> +
> +	return csum;
> +}
> +
>   static int check_image_header(void)
>   {
>   	u8 checksum;
> +	u32 checksum32, exp_checksum32;
>   	const struct a38x_main_hdr_v1 *hdr =
>   		(struct a38x_main_hdr_v1 *)get_load_addr();
>   	const size_t image_size = a38x_header_size(hdr);
> @@ -701,11 +716,39 @@ static int check_image_header(void)
>   	checksum = image_checksum8(hdr, image_size);
>   	checksum -= hdr->checksum;
>   	if (checksum != hdr->checksum) {
> -		printf("Error: Bad A38x image checksum. 0x%x != 0x%x\n",
> +		printf("Error: Bad A38x image header checksum. 0x%x != 0x%x\n",
>   		       checksum, hdr->checksum);
>   		return -ENOEXEC;
>   	}
>   
> +	offset = le32_to_cpu(hdr->srcaddr);
> +	size = le32_to_cpu(hdr->blocksize);

While running a world Azure CI build, I get these errors:

$ make clearfog_defconfig
$ make -sj
...
cmd/mvebu/bubt.c: In function 'check_image_header':
cmd/mvebu/bubt.c:724:9: error: 'offset' undeclared (first use in this 
function); did you mean 'off_t'?
   724 |         offset = le32_to_cpu(hdr->srcaddr);
       |         ^~~~~~
       |         off_t
cmd/mvebu/bubt.c:724:9: note: each undeclared identifier is reported 
only once for each function it appears in
cmd/mvebu/bubt.c:725:9: error: 'size' undeclared (first use in this 
function); did you mean 'size_t'?
   725 |         size = le32_to_cpu(hdr->blocksize);
       |         ^~~~
       |         size_t
make[2]: *** [scripts/Makefile.build:258: cmd/mvebu/bubt.o] Error 1
make[1]: *** [scripts/Makefile.build:398: cmd/mvebu] Error 2
make[1]: *** Waiting for unfinished jobs....
make: *** [Makefile:1916: cmd] Error 2
make: *** Waiting for unfinished jobs....

Could you please take a look and fix these issues?

Thanks,
Stefan

> +
> +	if (hdr->blockid == 0x78) { /* SATA id */
> +		if (offset < 1) {
> +			printf("Error: Bad A38x image srcaddr.\n");
> +			return -ENOEXEC;
> +		}
> +		offset -= 1;
> +		offset *= 512;
> +	}
> +
> +	if (hdr->blockid == 0xAE) /* SDIO id */
> +		offset *= 512;
> +
> +	if (offset % 4 != 0 || size < 4 || size % 4 != 0) {
> +		printf("Error: Bad A38x image blocksize.\n");
> +		return -ENOEXEC;
> +	}
> +
> +	checksum32 = image_checksum32((u8 *)hdr + offset, size - 4);
> +	exp_checksum32 = *(u32 *)((u8 *)hdr + offset + size - 4);
> +	if (checksum32 != exp_checksum32) {
> +		printf("Error: Bad A38x image data checksum. 0x%08x != 0x%08x\n",
> +		       checksum32, exp_checksum32);
> +		return -ENOEXEC;
> +	}
> +
>   	printf("Image checksum...OK!\n");
>   	return 0;
>   }

Viele Grüße,
Stefan Roese

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