tools: kwbimage: Verify size of image data

Part of image data is 4 byte checksum, so every image must contain at least
4 bytes. Verify it to prevent memory corruptions.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>

diff --git a/tools/kwbimage.c b/tools/kwbimage.c
index 4709c6d..f47e52f 100644 (file)
--- a/tools/kwbimage.c
+++ b/tools/kwbimage.c
@@ -1745,7 +1745,7 @@ static int kwbimage_verify_header(unsigned char *ptr, int image_size,
                        return -FDT_ERR_BADSTRUCTURE;
 
                size = le32_to_cpu(mhdr->blocksize);
-               if (offset + size > image_size || size % 4 != 0)
+               if (size < 4 || offset + size > image_size || size % 4 != 0)
                        return -FDT_ERR_BADSTRUCTURE;
 
                if (image_checksum32(ptr + offset, size - 4) !=