tools: kwboot: Validate 4-byte image data checksum

Data part of the image contains 4-byte checksum. Validate it when
processing the image.

Signed-off-by: Pali Rohár <pali@kernel.org>
[ refactored ]
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>

diff --git a/tools/kwboot.c b/tools/kwboot.c
index 4e29317..bc44301 100644 (file)
--- a/tools/kwboot.c
+++ b/tools/kwboot.c
@@ -1251,6 +1251,37 @@ kwboot_hdr_csum8(const void *hdr)
        return csum;
 }
 
+static uint32_t *
+kwboot_img_csum32_ptr(void *img)
+{
+       struct main_hdr_v1 *hdr = img;
+       uint32_t datasz;
+
+       datasz = le32_to_cpu(hdr->blocksize) - sizeof(uint32_t);
+
+       return img + le32_to_cpu(hdr->srcaddr) + datasz;
+}
+
+static uint32_t
+kwboot_img_csum32(const void *img)
+{
+       const struct main_hdr_v1 *hdr = img;
+       uint32_t datasz, csum = 0;
+       const uint32_t *data;
+
+       datasz = le32_to_cpu(hdr->blocksize) - sizeof(csum);
+       if (datasz % sizeof(uint32_t))
+               return 0;
+
+       data = img + le32_to_cpu(hdr->srcaddr);
+       while (datasz > 0) {
+               csum += le32_to_cpu(*data++);
+               datasz -= 4;
+       }
+
+       return cpu_to_le32(csum);
+}
+
 static int
 kwboot_img_is_secure(void *img)
 {
@@ -1462,6 +1493,9 @@ kwboot_img_patch(void *img, size_t *size, int baudrate)
            *size < le32_to_cpu(hdr->srcaddr) + le32_to_cpu(hdr->blocksize))
                goto err;
 
+       if (kwboot_img_csum32(img) != *kwboot_img_csum32_ptr(img))
+               goto err;
+
        is_secure = kwboot_img_is_secure(img);
 
        if (hdr->blockid != IBR_HDR_UART_ID) {