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

[Stefan Roese]

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 <p...@kernel.org>

Reviewed-by: Stefan Roese <s...@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

--
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-51 Fax: (+49)-8142-66989-80 Email: s...@denx.de