From cd341a0cd7d698b816b55a0f6e2e9ae9aeeea3bb Mon Sep 17 00:00:00 2001 From: Vadim Bendebury Date: Wed, 6 Jul 2016 09:01:05 -0700 Subject: [PATCH] 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 Reviewed-on: https://chromium-review.googlesource.com/358175 Reviewed-by: Randall Spangler --- firmware/2lib/2api.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/firmware/2lib/2api.c b/firmware/2lib/2api.c index 059cb6c29e..c12a8051c8 100644 --- a/firmware/2lib/2api.c +++ b/firmware/2lib/2api.c @@ -199,6 +199,9 @@ int vb2api_get_pcr_digest(struct vb2_context *ctx, 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;