cbfstool: Expand CBFS verification validity check

This patch adds a new line to `cbfstool print -v` output that records
the overall CBFS verification health of the image. While this info was
already visible from individual fields before, it's nice to have a
one-stop location to see "this is a good image" without having to
carefully parse a lot of output manually.

Also add a few lines to the Makefile that check whether this field is
valid for the final image (it always should be, but hopefully this check
will allow us to catch regressions like the one fixed by CB:64547 sooner
in the future).

BUG=b:233263447

Signed-off-by: Julius Werner <jwerner@chromium.org>
Change-Id: I1b74b01a55b22294556007aaee835d0fdb9e1c63
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64657
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>

1 files changed, 29 insertions, 8 deletions

diff --git a/util/cbfstool/cbfstool.c b/util/cbfstool/cbfstool.c
index 71c8911ede21..ff10131e4744 100644
--- a/util/cbfstool/cbfstool.c
+++ b/util/cbfstool/cbfstool.c
@@ -1499,6 +1499,23 @@ static int cbfs_layout(void)
 	return 0;
 }
 
+static enum cb_err verify_walker(__unused cbfs_dev_t dev, size_t offset,
+				 const union cbfs_mdata *mdata, size_t already_read, void *arg)
+{
+	uint32_t type = be32toh(mdata->h.type);
+	uint32_t data_offset = be32toh(mdata->h.offset);
+	if (verification_exclude(type))
+		return CB_CBFS_NOT_FOUND;
+	assert(already_read == data_offset);
+	const struct vb2_hash *hash = cbfs_file_hash(mdata);
+	if (!hash)
+		return CB_ERR;
+	void *file_data = arg + offset + data_offset;
+	if (vb2_hash_verify(file_data, be32toh(mdata->h.len), hash) != VB2_SUCCESS)
+		return CB_CBFS_HASH_MISMATCH;
+	return CB_CBFS_NOT_FOUND;
+}
+
 static int cbfs_print(void)
 {
 	struct cbfs_image image;
@@ -1515,29 +1532,33 @@ static int cbfs_print(void)
 	}
 
 	if (verbose) {
+		const char *verification_state = "fully valid";
 		struct mh_cache *mhc = get_mh_cache();
 		if (mhc->cbfs_hash.algo == VB2_HASH_INVALID)
 			return 0;
 
 		struct vb2_hash real_hash = { .algo = mhc->cbfs_hash.algo };
-		enum cb_err err = cbfs_walk(&image, NULL, NULL, &real_hash,
-					    CBFS_WALK_WRITEBACK_HASH);
-		if (err != CB_CBFS_NOT_FOUND) {
-			ERROR("Unexpected cbfs_walk() error %d\n", err);
-			return 1;
-		}
+		enum cb_err err = cbfs_walk(&image, verify_walker, buffer_get(&image.buffer),
+					    &real_hash, CBFS_WALK_WRITEBACK_HASH);
+		if (err == CB_CBFS_HASH_MISMATCH)
+			verification_state = "invalid file hashes";
+		else if (err != CB_CBFS_NOT_FOUND)
+			verification_state = "missing file hashes";
 		char *hash_str = bintohex(real_hash.raw,
 				vb2_digest_size(real_hash.algo));
 		printf("[METADATA HASH]\t%s:%s",
 		       vb2_get_hash_algorithm_name(real_hash.algo), hash_str);
 		if (!strcmp(param.region_name, SECTION_NAME_PRIMARY_CBFS)) {
 			if (!memcmp(mhc->cbfs_hash.raw, real_hash.raw,
-				    vb2_digest_size(real_hash.algo)))
+				    vb2_digest_size(real_hash.algo))) {
 				printf(":valid");
-			else
+			} else {
 				printf(":invalid");
+				verification_state = "invalid metadata hash";
+			}
 		}
 		printf("\n");
+		printf("[CBFS VERIFICATION (%s)]\t%s\n", param.region_name, verification_state);
 		free(hash_str);
 	}