tools: kwboot: Explicitly check against size of struct main_hdr_v1

Explicitly check the image size against size of struct main_hdr_v1.
This way the check is more readable, since the `hdrsz` variable
may semantically contain another value.

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 4fae44c..77bf5cb 100644 (file)
--- a/tools/kwboot.c
+++ b/tools/kwboot.c
@@ -820,14 +820,14 @@ kwboot_img_patch_hdr(void *img, size_t *size)
        struct main_hdr_v1 *hdr;
        uint32_t srcaddr;
        uint8_t csum;
-       size_t hdrsz = sizeof(*hdr);
+       size_t hdrsz;
        int image_ver;
        int is_secure;
 
        rc = -1;
        hdr = img;
 
-       if (*size < hdrsz) {
+       if (*size < sizeof(struct main_hdr_v1)) {
                errno = EINVAL;
                goto out;
        }