vb2api: pad digest buffers if they are larger than digest sizes
Extending tpm PCRs in case of TPM2 requires 32 bit values, some
digests pre-calculated in vboot source code are 20 bytes in size. To
make sure that PCR extension is consistent, pad remaining buffer space
when a 20 byte digest is returned in a 32 byte buffer.
BRANCH=none
BUG=chrome-os-partner:50645
TEST=did not verify much, made sure that PCR extension commands
triggered by coreboot succeed.
Change-Id: Ib16bdf782f18a6106eadb4b880cd1e67b56ad6db
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/358175
Reviewed-by: Randall Spangler <rspangler@chromium.org>
(cherry picked from commit cd341a0cd7d698b816b55a0f6e2e9ae9aeeea3bb)
Reviewed-on: https://chromium-review.googlesource.com/358933
Reviewed-by: Bernie Thompson <bhthompson@chromium.org>
Commit-Queue: Bernie Thompson <bhthompson@chromium.org>
Tested-by: Bernie Thompson <bhthompson@chromium.org>
diff --git a/firmware/2lib/2api.c b/firmware/2lib/2api.c
index 059cb6c..c12a805 100644
--- a/firmware/2lib/2api.c
+++ b/firmware/2lib/2api.c
@@ -199,6 +199,9 @@
return VB2_ERROR_API_PCR_DIGEST_BUF;
memcpy(dest, digest, digest_size);
+ if (digest_size < *dest_size)
+ memset(dest + digest_size, 0, *dest_size - digest_size);
+
*dest_size = digest_size;
return VB2_SUCCESS;
