vboot2: Add api-level functions to use new data structures

And associated unit tests.

And fix a memory overwrite in the old vb_api_tests.c, which apparently
didn't touch a critical piece of the shared work buffer, but was still
wrong.  (This was a problem in the test, not in the code being
tested.)

BUG=chromium:423882
BRANCH=none
TEST=VBOOT2=1 make runtests

Change-Id: I322fb7e6bb5214b0adcf5d6d48a0cd238abba88e
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/229738
Reviewed-by: Bill Richardson <wfrichar@chromium.org>

4 files changed, 179 insertions, 4 deletions

diff --git a/firmware/2lib/2api2.c b/firmware/2lib/2api2.c
new file mode 100644
index 00000000..0df2cf69
--- /dev/null
+++ b/firmware/2lib/2api2.c
@@ -0,0 +1,146 @@
+/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Externally-callable APIs
+ * (Firmware portion)
+ */
+
+#include "2sysincludes.h"
+#include "2api.h"
+#include "2common.h"
+#include "2misc.h"
+#include "2nvstorage.h"
+#include "2secdata.h"
+#include "2sha.h"
+#include "2rsa.h"
+
+int vb2api_fw_phase3_2(struct vb2_context *ctx)
+{
+	int rv;
+
+	/* Verify firmware keyblock */
+	rv = vb2_load_fw_keyblock2(ctx);
+	if (rv) {
+		vb2_fail(ctx, VB2_RECOVERY_RO_INVALID_RW, rv);
+		return rv;
+	}
+
+	/* Verify firmware preamble */
+	rv = vb2_load_fw_preamble2(ctx);
+	if (rv) {
+		vb2_fail(ctx, VB2_RECOVERY_RO_INVALID_RW, rv);
+		return rv;
+	}
+
+	return VB2_SUCCESS;
+}
+
+int vb2api_init_hash2(struct vb2_context *ctx,
+		      const struct vb2_guid *guid,
+		      uint32_t *size)
+{
+	struct vb2_shared_data *sd = vb2_get_sd(ctx);
+	const struct vb2_fw_preamble2 *pre;
+	const struct vb2_signature2 *sig = NULL;
+	struct vb2_digest_context *dc;
+	struct vb2_workbuf wb;
+	uint32_t hash_offset;
+	int i;
+
+	vb2_workbuf_from_ctx(ctx, &wb);
+
+	/* Get preamble pointer */
+	if (!sd->workbuf_preamble_size)
+		return VB2_ERROR_API_INIT_HASH_PREAMBLE;
+	pre = (const struct vb2_fw_preamble2 *)
+		(ctx->workbuf + sd->workbuf_preamble_offset);
+
+	/* Find the matching signature */
+	hash_offset = pre->hash_offset;
+	for (i = 0; i < pre->hash_count; i++) {
+		sig = (const struct vb2_signature2 *)
+			((uint8_t *)pre + hash_offset);
+
+		if (!memcmp(guid, &sig->guid, sizeof(*guid)))
+			break;
+
+		hash_offset += sig->c.total_size;
+	}
+	if (i >= pre->hash_count)
+		return VB2_ERROR_API_INIT_HASH_GUID;  /* No match */
+
+	/* Allocate workbuf space for the hash */
+	if (sd->workbuf_hash_size) {
+		dc = (struct vb2_digest_context *)
+			(ctx->workbuf + sd->workbuf_hash_offset);
+	} else {
+		uint32_t dig_size = sizeof(*dc);
+
+		dc = vb2_workbuf_alloc(&wb, dig_size);
+		if (!dc)
+			return VB2_ERROR_API_INIT_HASH_WORKBUF;
+
+		sd->workbuf_hash_offset = vb2_offset_of(ctx->workbuf, dc);
+		sd->workbuf_hash_size = dig_size;
+		ctx->workbuf_used = sd->workbuf_hash_offset + dig_size;
+	}
+
+	sd->hash_tag = vb2_offset_of(ctx->workbuf, sig);
+	sd->hash_remaining_size = sig->data_size;
+
+	if (size)
+		*size = sig->data_size;
+
+	return vb2_digest_init(dc, sig->hash_alg);
+}
+
+int vb2api_check_hash2(struct vb2_context *ctx)
+{
+	struct vb2_shared_data *sd = vb2_get_sd(ctx);
+	struct vb2_digest_context *dc = (struct vb2_digest_context *)
+		(ctx->workbuf + sd->workbuf_hash_offset);
+	struct vb2_workbuf wb;
+
+	uint8_t *digest;
+	uint32_t digest_size = vb2_digest_size(dc->hash_alg);
+
+	const struct vb2_signature2 *sig;
+
+	int rv;
+
+	vb2_workbuf_from_ctx(ctx, &wb);
+
+	/* Get signature pointer */
+	if (!sd->hash_tag)
+		return VB2_ERROR_API_CHECK_HASH_TAG;
+	sig = (const struct vb2_signature2 *)(ctx->workbuf + sd->hash_tag);
+
+	/* Must have initialized hash digest work area */
+	if (!sd->workbuf_hash_size)
+		return VB2_ERROR_API_CHECK_HASH_WORKBUF;
+
+	/* Should have hashed the right amount of data */
+	if (sd->hash_remaining_size)
+		return VB2_ERROR_API_CHECK_HASH_SIZE;
+
+	/* Allocate the digest */
+	digest = vb2_workbuf_alloc(&wb, digest_size);
+	if (!digest)
+		return VB2_ERROR_API_CHECK_HASH_WORKBUF_DIGEST;
+
+	/* Finalize the digest */
+	rv = vb2_digest_finalize(dc, digest, digest_size);
+	if (rv)
+		return rv;
+
+	/* Compare with the signature */
+	if (vb2_safe_memcmp(digest, (const uint8_t *)sig + sig->sig_offset,
+			    digest_size))
+		return VB2_ERROR_API_CHECK_HASH_SIG;
+
+	// TODO: the old check-hash function called vb2_fail() on any mismatch.
+	// I don't think it should do that; the caller should.
+
+	return VB2_SUCCESS;
+}
diff --git a/firmware/2lib/include/2api.h b/firmware/2lib/include/2api.h
index 603e0953..c0727c76 100644
--- a/firmware/2lib/include/2api.h
+++ b/firmware/2lib/include/2api.h
@@ -297,6 +297,11 @@ int vb2api_fw_phase2(struct vb2_context *ctx);
 int vb2api_fw_phase3(struct vb2_context *ctx);
 
 /**
+ * Same, but for new-style structs.
+ */
+int vb2api_fw_phase3_2(struct vb2_context *ctx);
+
+/**
  * Initialize hashing data for the specified tag.
  *
  * @param ctx		Vboot context
@@ -308,8 +313,17 @@ int vb2api_fw_phase3(struct vb2_context *ctx);
 int vb2api_init_hash(struct vb2_context *ctx, uint32_t tag, uint32_t *size);
 
 /**
+ * Same, but for new-style structs.
+ */
+int vb2api_init_hash2(struct vb2_context *ctx,
+		      const struct vb2_guid *guid,
+		      uint32_t *size);
+
+/**
  * Extend the hash started by vb2api_init_hash() with additional data.
  *
+ * (This is the same for both old and new style structs.)
+ *
  * @param ctx		Vboot context
  * @param buf		Data to hash
  * @param size		Size of data in bytes
@@ -327,9 +341,10 @@ int vb2api_extend_hash(struct vb2_context *ctx,
  */
 int vb2api_check_hash(struct vb2_context *ctx);
 
-int vb2api_get_kernel_subkey(struct vb2_context *ctx,
-			     uint8_t *buf,
-			     uint32_t *size);
+/**
+ * Same, but for new-style structs.
+ */
+int vb2api_check_hash2(struct vb2_context *ctx);
 
 /*****************************************************************************/
 /* APIs provided by the caller to verified boot */
diff --git a/firmware/2lib/include/2return_codes.h b/firmware/2lib/include/2return_codes.h
index 259726d1..fa7437e0 100644
--- a/firmware/2lib/include/2return_codes.h
+++ b/firmware/2lib/include/2return_codes.h
@@ -414,6 +414,12 @@ enum vb2_return_code {
 	/* Phase one needs recovery mode */
 	VB2_ERROR_API_PHASE1_RECOVERY,
 
+	/* Bag tag in vb2api_check_hash() */
+	VB2_ERROR_API_INIT_HASH_GUID,
+
+	/* Siganature mismatch in vb2api_check_hash() */
+	VB2_ERROR_API_CHECK_HASH_SIG,
+
         /**********************************************************************
 	 * Errors which may be generated by implementations of vb2ex functions.
 	 * Implementation may also return its own specific errors, which should
diff --git a/firmware/2lib/include/2struct.h b/firmware/2lib/include/2struct.h
index de67bfc3..dd956219 100644
--- a/firmware/2lib/include/2struct.h
+++ b/firmware/2lib/include/2struct.h
@@ -611,7 +611,15 @@ struct vb2_shared_data {
 	uint32_t workbuf_hash_offset;
 	uint32_t workbuf_hash_size;
 
-	/* Current tag we're hashing */
+	/*
+	 * Current tag we're hashing
+	 *
+	 * For new structs, this is the offset of the vb2_signature2 struct
+	 * in the work buffer.
+	 *
+	 * TODO: rename to workbuf_hash_sig_offset when vboot1 structs are
+	 * deprecated.
+	 */
 	uint32_t hash_tag;
 
 	/* Amount of data we still expect to hash */