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

Stefan Roese
2022-08-17T06:14:52Z

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@kernel.org>

Reviewed-by: Stefan Roese <sr@denx.de>

Thanks,
Stefan

> ---
> 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);
> +
> + 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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