tools: kwbimage: Fix generating secure boot data image signature
Secure boot data image signature is calculated from the data image without
trailing 4-bit checksum. Commit 37cb9c15d70d ("tools: kwbimage: Simplify
aligning and calculating checksum") unintentionally broke this calculation
when it increased payloadsz variable by 4 bytes which was propagated also
into the add_secure_header_v1() function. Fix this issue by decreasing size
of buffer by 4 bytes from which is calculated secure boot data image
signature.
Fixes: 37cb9c15d70d ("tools: kwbimage: Simplify aligning and calculating checksum")
Signed-off-by: Pali Rohár <pali@kernel.org>
diff --git a/tools/kwbimage.c b/tools/kwbimage.c
index b32f845..a8a59c1 100644
--- a/tools/kwbimage.c
+++ b/tools/kwbimage.c
@@ -1355,7 +1355,7 @@
if (kwb_sign_csk_with_kak(params, secure_hdr, csk))
return 1;
- if (kwb_sign_and_verify(csk, image_ptr, image_size,
+ if (kwb_sign_and_verify(csk, image_ptr, image_size - 4,
&secure_hdr->imgsig, "image") < 0)
return 1;