firmware/lib20/common.c - mirrors/cros/chromiumos/platform/vboot_reference - Git at Google

 /* 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.
  *
  * Common functions between firmware and kernel verified boot.
  * (Firmware portion)
  */

 #include "2sysincludes.h"
 #include "2rsa.h"
 #include "2sha.h"
 #include "vb2_common.h"

 uint8_t *vb2_signature_data(struct vb2_signature *sig)
 {
 	return (uint8_t *)sig + sig->sig_offset;
 }

 int vb2_verify_member_inside(const void *parent, size_t parent_size,
 			     const void *member, size_t member_size,
 			     ptrdiff_t member_data_offset,
 			     size_t member_data_size)
 {
 	const uintptr_t parent_end = (uintptr_t)parent + parent_size;
 	const ptrdiff_t member_offs = vb2_offset_of(parent, member);
 	const ptrdiff_t member_end_offs = member_offs + member_size;
 	const ptrdiff_t data_offs = member_offs + member_data_offset;
 	const ptrdiff_t data_end_offs = data_offs + member_data_size;

 	/* Make sure parent doesn't wrap */
 	if (parent_size < 0 || parent_end < (uintptr_t)parent)
 		return VB2_ERROR_INSIDE_PARENT_WRAPS;

 	/*
 	 * Make sure the member is fully contained in the parent and doesn't
 	 * wrap.  Use >, not >=, since member_size = 0 is possible.
 	 */
 	if (member_size < 0 || member_end_offs < member_offs)
 		return VB2_ERROR_INSIDE_MEMBER_WRAPS;
 	if (member_offs < 0 || member_offs > parent_size ||
 	    member_end_offs > parent_size)
 		return VB2_ERROR_INSIDE_MEMBER_OUTSIDE;

 	/* Make sure the member data is after the member */
 	if (member_data_size > 0 && data_offs < member_end_offs)
 		return VB2_ERROR_INSIDE_DATA_OVERLAP;

 	/* Make sure parent fully contains member data, if any */
 	if (member_data_size < 0 || data_end_offs < data_offs)
 		return VB2_ERROR_INSIDE_DATA_WRAPS;
 	if (data_offs < 0 || data_offs > parent_size ||
 	    data_end_offs > parent_size)
 		return VB2_ERROR_INSIDE_DATA_OUTSIDE;

 	return VB2_SUCCESS;
 }

 int vb2_verify_signature_inside(const void *parent,
 				uint32_t parent_size,
 				const struct vb2_signature *sig)
 {
 	return vb2_verify_member_inside(parent, parent_size,
 					sig, sizeof(*sig),
 					sig->sig_offset, sig->sig_size);
 }

 int vb2_verify_digest(const struct vb2_public_key *key,
 		      struct vb2_signature *sig,
 		      const uint8_t *digest,
 		      const struct vb2_workbuf *wb)
 {
 	uint8_t *sig_data = vb2_signature_data(sig);

 	if (sig->sig_size != vb2_rsa_sig_size(key->sig_alg)) {
 		VB2_DEBUG("Wrong data signature size for algorithm, "
 			  "sig_size=%d, expected %d for algorithm %d.\n",
 			  sig->sig_size, vb2_rsa_sig_size(key->sig_alg),
 			  key->sig_alg);
 		return VB2_ERROR_VDATA_SIG_SIZE;
 	}

 	return vb2_rsa_verify_digest(key, sig_data, digest, wb);
 }

 int vb2_verify_data(const uint8_t *data,
 		    uint32_t size,
 		    struct vb2_signature *sig,
 		    const struct vb2_public_key *key,
 		    const struct vb2_workbuf *wb)
 {
 	struct vb2_workbuf wblocal = *wb;
 	struct vb2_digest_context *dc;
 	uint8_t *digest;
 	uint32_t digest_size;
 	int rv;

 	if (sig->data_size > size) {
 		VB2_DEBUG("Data buffer smaller than length of signed data.\n");
 		return VB2_ERROR_VDATA_NOT_ENOUGH_DATA;
 	}

 	/* Digest goes at start of work buffer */
 	digest_size = vb2_digest_size(key->hash_alg);
 	if (!digest_size)
 		return VB2_ERROR_VDATA_DIGEST_SIZE;

 	digest = vb2_workbuf_alloc(&wblocal, digest_size);
 	if (!digest)
 		return VB2_ERROR_VDATA_WORKBUF_DIGEST;

 	/* Hashing requires temp space for the context */
 	dc = vb2_workbuf_alloc(&wblocal, sizeof(*dc));
 	if (!dc)
 		return VB2_ERROR_VDATA_WORKBUF_HASHING;

 	rv = vb2_digest_init(dc, key->hash_alg);
 	if (rv)
 		return rv;

 	rv = vb2_digest_extend(dc, data, sig->data_size);
 	if (rv)
 		return rv;

 	rv = vb2_digest_finalize(dc, digest, digest_size);
 	if (rv)
 		return rv;

 	vb2_workbuf_free(&wblocal, sizeof(*dc));

 	return vb2_verify_digest(key, sig, digest, &wblocal);
 }

 int vb2_verify_keyblock(struct vb2_keyblock *block,
 			uint32_t size,
 			const struct vb2_public_key *key,
 			const struct vb2_workbuf *wb)
 {
 	struct vb2_signature *sig;
 	int rv;

 	/* Sanity checks before attempting signature of data */
 	if(size < sizeof(*block)) {
 		VB2_DEBUG("Not enough space for key block header.\n");
 		return VB2_ERROR_KEYBLOCK_TOO_SMALL_FOR_HEADER;
 	}
 	if (memcmp(block->magic, KEY_BLOCK_MAGIC, KEY_BLOCK_MAGIC_SIZE)) {
 		VB2_DEBUG("Not a valid verified boot key block.\n");
 		return VB2_ERROR_KEYBLOCK_MAGIC;
 	}
 	if (block->header_version_major != KEY_BLOCK_HEADER_VERSION_MAJOR) {
 		VB2_DEBUG("Incompatible key block header version.\n");
 		return VB2_ERROR_KEYBLOCK_HEADER_VERSION;
 	}
 	if (size < block->keyblock_size) {
 		VB2_DEBUG("Not enough data for key block.\n");
 		return VB2_ERROR_KEYBLOCK_SIZE;
 	}

 	/* Check signature */
 	sig = &block->keyblock_signature;

 	if (vb2_verify_signature_inside(block, block->keyblock_size, sig)) {
 		VB2_DEBUG("Key block signature off end of block\n");
 		return VB2_ERROR_KEYBLOCK_SIG_OUTSIDE;
 	}

 	/* Make sure advertised signature data sizes are sane. */
 	if (block->keyblock_size < sig->data_size) {
 		VB2_DEBUG("Signature calculated past end of block\n");
 		return VB2_ERROR_KEYBLOCK_SIGNED_TOO_MUCH;
 	}

 	VB2_DEBUG("Checking key block signature...\n");
 	rv = vb2_verify_data((const uint8_t *)block, size, sig, key, wb);
 	if (rv) {
 		VB2_DEBUG("Invalid key block signature.\n");
 		return VB2_ERROR_KEYBLOCK_SIG_INVALID;
 	}

 	/* Verify we signed enough data */
 	if (sig->data_size < sizeof(struct vb2_keyblock)) {
 		VB2_DEBUG("Didn't sign enough data\n");
 		return VB2_ERROR_KEYBLOCK_SIGNED_TOO_LITTLE;
 	}

 	/* Verify data key is inside the block and inside signed data */
 	if (vb2_verify_packed_key_inside(block, block->keyblock_size,
 					 &block->data_key)) {
 		VB2_DEBUG("Data key off end of key block\n");
 		return VB2_ERROR_KEYBLOCK_DATA_KEY_OUTSIDE;
 	}
 	if (vb2_verify_packed_key_inside(block, sig->data_size,
 					 &block->data_key)) {
 		VB2_DEBUG("Data key off end of signed data\n");
 		return VB2_ERROR_KEYBLOCK_DATA_KEY_UNSIGNED;
 	}

 	/* Success */
 	return VB2_SUCCESS;
 }

 int vb2_verify_fw_preamble(struct vb2_fw_preamble *preamble,
 			   uint32_t size,
 			   const struct vb2_public_key *key,
 			   const struct vb2_workbuf *wb)
 {
 	struct vb2_signature *sig = &preamble->preamble_signature;

 	VB2_DEBUG("Verifying preamble.\n");

 	/* Sanity checks before attempting signature of data */
 	if(size < sizeof(*preamble)) {
 		VB2_DEBUG("Not enough data for preamble header\n");
 		return VB2_ERROR_PREAMBLE_TOO_SMALL_FOR_HEADER;
 	}
 	if (preamble->header_version_major !=
 	    FIRMWARE_PREAMBLE_HEADER_VERSION_MAJOR) {
 		VB2_DEBUG("Incompatible firmware preamble header version.\n");
 		return VB2_ERROR_PREAMBLE_HEADER_VERSION;
 	}

 	if (preamble->header_version_minor < 1) {
 		VB2_DEBUG("Only preamble header 2.1+ supported\n");
 		return VB2_ERROR_PREAMBLE_HEADER_OLD;
 	}

 	if (size < preamble->preamble_size) {
 		VB2_DEBUG("Not enough data for preamble.\n");
 		return VB2_ERROR_PREAMBLE_SIZE;
 	}

 	/* Check signature */
 	if (vb2_verify_signature_inside(preamble, preamble->preamble_size,
 					sig)) {
 		VB2_DEBUG("Preamble signature off end of preamble\n");
 		return VB2_ERROR_PREAMBLE_SIG_OUTSIDE;
 	}

 	/* Make sure advertised signature data sizes are sane. */
 	if (preamble->preamble_size < sig->data_size) {
 		VB2_DEBUG("Signature calculated past end of the block\n");
 		return VB2_ERROR_PREAMBLE_SIGNED_TOO_MUCH;
 	}

 	if (vb2_verify_data((const uint8_t *)preamble, size, sig, key, wb)) {
 		VB2_DEBUG("Preamble signature validation failed\n");
 		return VB2_ERROR_PREAMBLE_SIG_INVALID;
 	}

 	/* Verify we signed enough data */
 	if (sig->data_size < sizeof(struct vb2_fw_preamble)) {
 		VB2_DEBUG("Didn't sign enough data\n");
 		return VB2_ERROR_PREAMBLE_SIGNED_TOO_LITTLE;
 	}

 	/* Verify body signature is inside the signed data */
 	if (vb2_verify_signature_inside(preamble, sig->data_size,
 					&preamble->body_signature)) {
 		VB2_DEBUG("Firmware body signature off end of preamble\n");
 		return VB2_ERROR_PREAMBLE_BODY_SIG_OUTSIDE;
 	}

 	/* Verify kernel subkey is inside the signed data */
 	if (vb2_verify_packed_key_inside(preamble, sig->data_size,
 					 &preamble->kernel_subkey)) {
 		VB2_DEBUG("Kernel subkey off end of preamble\n");
 		return VB2_ERROR_PREAMBLE_KERNEL_SUBKEY_OUTSIDE;
 	}

 	/* Success */
 	return VB2_SUCCESS;
 }
	/* 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.
	*
	* Common functions between firmware and kernel verified boot.
	* (Firmware portion)
	*/

	#include "2sysincludes.h"
	#include "2rsa.h"
	#include "2sha.h"
	#include "vb2_common.h"

	uint8_t vb2_signature_data(struct vb2_signature sig)
	{
	return (uint8_t *)sig + sig->sig_offset;
	}

	int vb2_verify_member_inside(const void *parent, size_t parent_size,
	const void *member, size_t member_size,
	ptrdiff_t member_data_offset,
	size_t member_data_size)
	{
	const uintptr_t parent_end = (uintptr_t)parent + parent_size;
	const ptrdiff_t member_offs = vb2_offset_of(parent, member);
	const ptrdiff_t member_end_offs = member_offs + member_size;
	const ptrdiff_t data_offs = member_offs + member_data_offset;
	const ptrdiff_t data_end_offs = data_offs + member_data_size;

	/* Make sure parent doesn't wrap */
	if (parent_size < 0 \|\| parent_end < (uintptr_t)parent)
	return VB2_ERROR_INSIDE_PARENT_WRAPS;

	/*
	* Make sure the member is fully contained in the parent and doesn't
	* wrap. Use >, not >=, since member_size = 0 is possible.
	*/
	if (member_size < 0 \|\| member_end_offs < member_offs)
	return VB2_ERROR_INSIDE_MEMBER_WRAPS;
	if (member_offs < 0 \|\| member_offs > parent_size \|\|
	member_end_offs > parent_size)
	return VB2_ERROR_INSIDE_MEMBER_OUTSIDE;

	/* Make sure the member data is after the member */
	if (member_data_size > 0 && data_offs < member_end_offs)
	return VB2_ERROR_INSIDE_DATA_OVERLAP;

	/* Make sure parent fully contains member data, if any */
	if (member_data_size < 0 \|\| data_end_offs < data_offs)
	return VB2_ERROR_INSIDE_DATA_WRAPS;
	if (data_offs < 0 \|\| data_offs > parent_size \|\|
	data_end_offs > parent_size)
	return VB2_ERROR_INSIDE_DATA_OUTSIDE;

	return VB2_SUCCESS;
	}

	int vb2_verify_signature_inside(const void *parent,
	uint32_t parent_size,
	const struct vb2_signature *sig)
	{
	return vb2_verify_member_inside(parent, parent_size,
	sig, sizeof(*sig),
	sig->sig_offset, sig->sig_size);
	}

	int vb2_verify_digest(const struct vb2_public_key *key,
	struct vb2_signature *sig,
	const uint8_t *digest,
	const struct vb2_workbuf *wb)
	{
	uint8_t *sig_data = vb2_signature_data(sig);

	if (sig->sig_size != vb2_rsa_sig_size(key->sig_alg)) {
	VB2_DEBUG("Wrong data signature size for algorithm, "
	"sig_size=%d, expected %d for algorithm %d.\n",
	sig->sig_size, vb2_rsa_sig_size(key->sig_alg),
	key->sig_alg);
	return VB2_ERROR_VDATA_SIG_SIZE;
	}

	return vb2_rsa_verify_digest(key, sig_data, digest, wb);
	}

	int vb2_verify_data(const uint8_t *data,
	uint32_t size,
	struct vb2_signature *sig,
	const struct vb2_public_key *key,
	const struct vb2_workbuf *wb)
	{
	struct vb2_workbuf wblocal = *wb;
	struct vb2_digest_context *dc;
	uint8_t *digest;
	uint32_t digest_size;
	int rv;

	if (sig->data_size > size) {
	VB2_DEBUG("Data buffer smaller than length of signed data.\n");
	return VB2_ERROR_VDATA_NOT_ENOUGH_DATA;
	}

	/* Digest goes at start of work buffer */
	digest_size = vb2_digest_size(key->hash_alg);
	if (!digest_size)
	return VB2_ERROR_VDATA_DIGEST_SIZE;

	digest = vb2_workbuf_alloc(&wblocal, digest_size);
	if (!digest)
	return VB2_ERROR_VDATA_WORKBUF_DIGEST;

	/* Hashing requires temp space for the context */
	dc = vb2_workbuf_alloc(&wblocal, sizeof(*dc));
	if (!dc)
	return VB2_ERROR_VDATA_WORKBUF_HASHING;

	rv = vb2_digest_init(dc, key->hash_alg);
	if (rv)
	return rv;

	rv = vb2_digest_extend(dc, data, sig->data_size);
	if (rv)
	return rv;

	rv = vb2_digest_finalize(dc, digest, digest_size);
	if (rv)
	return rv;

	vb2_workbuf_free(&wblocal, sizeof(*dc));

	return vb2_verify_digest(key, sig, digest, &wblocal);
	}

	int vb2_verify_keyblock(struct vb2_keyblock *block,
	uint32_t size,
	const struct vb2_public_key *key,
	const struct vb2_workbuf *wb)
	{
	struct vb2_signature *sig;
	int rv;

	/* Sanity checks before attempting signature of data */
	if(size < sizeof(*block)) {
	VB2_DEBUG("Not enough space for key block header.\n");
	return VB2_ERROR_KEYBLOCK_TOO_SMALL_FOR_HEADER;
	}
	if (memcmp(block->magic, KEY_BLOCK_MAGIC, KEY_BLOCK_MAGIC_SIZE)) {
	VB2_DEBUG("Not a valid verified boot key block.\n");
	return VB2_ERROR_KEYBLOCK_MAGIC;
	}
	if (block->header_version_major != KEY_BLOCK_HEADER_VERSION_MAJOR) {
	VB2_DEBUG("Incompatible key block header version.\n");
	return VB2_ERROR_KEYBLOCK_HEADER_VERSION;
	}
	if (size < block->keyblock_size) {
	VB2_DEBUG("Not enough data for key block.\n");
	return VB2_ERROR_KEYBLOCK_SIZE;
	}

	/* Check signature */
	sig = &block->keyblock_signature;

	if (vb2_verify_signature_inside(block, block->keyblock_size, sig)) {
	VB2_DEBUG("Key block signature off end of block\n");
	return VB2_ERROR_KEYBLOCK_SIG_OUTSIDE;
	}

	/* Make sure advertised signature data sizes are sane. */
	if (block->keyblock_size < sig->data_size) {
	VB2_DEBUG("Signature calculated past end of block\n");
	return VB2_ERROR_KEYBLOCK_SIGNED_TOO_MUCH;
	}

	VB2_DEBUG("Checking key block signature...\n");
	rv = vb2_verify_data((const uint8_t *)block, size, sig, key, wb);
	if (rv) {
	VB2_DEBUG("Invalid key block signature.\n");
	return VB2_ERROR_KEYBLOCK_SIG_INVALID;
	}

	/* Verify we signed enough data */
	if (sig->data_size < sizeof(struct vb2_keyblock)) {
	VB2_DEBUG("Didn't sign enough data\n");
	return VB2_ERROR_KEYBLOCK_SIGNED_TOO_LITTLE;
	}

	/* Verify data key is inside the block and inside signed data */
	if (vb2_verify_packed_key_inside(block, block->keyblock_size,
	&block->data_key)) {
	VB2_DEBUG("Data key off end of key block\n");
	return VB2_ERROR_KEYBLOCK_DATA_KEY_OUTSIDE;
	}
	if (vb2_verify_packed_key_inside(block, sig->data_size,
	&block->data_key)) {
	VB2_DEBUG("Data key off end of signed data\n");
	return VB2_ERROR_KEYBLOCK_DATA_KEY_UNSIGNED;
	}

	/* Success */
	return VB2_SUCCESS;
	}

	int vb2_verify_fw_preamble(struct vb2_fw_preamble *preamble,
	uint32_t size,
	const struct vb2_public_key *key,
	const struct vb2_workbuf *wb)
	{
	struct vb2_signature *sig = &preamble->preamble_signature;

	VB2_DEBUG("Verifying preamble.\n");

	/* Sanity checks before attempting signature of data */
	if(size < sizeof(*preamble)) {
	VB2_DEBUG("Not enough data for preamble header\n");
	return VB2_ERROR_PREAMBLE_TOO_SMALL_FOR_HEADER;
	}
	if (preamble->header_version_major !=
	FIRMWARE_PREAMBLE_HEADER_VERSION_MAJOR) {
	VB2_DEBUG("Incompatible firmware preamble header version.\n");
	return VB2_ERROR_PREAMBLE_HEADER_VERSION;
	}

	if (preamble->header_version_minor < 1) {
	VB2_DEBUG("Only preamble header 2.1+ supported\n");
	return VB2_ERROR_PREAMBLE_HEADER_OLD;
	}

	if (size < preamble->preamble_size) {
	VB2_DEBUG("Not enough data for preamble.\n");
	return VB2_ERROR_PREAMBLE_SIZE;
	}

	/* Check signature */
	if (vb2_verify_signature_inside(preamble, preamble->preamble_size,
	sig)) {
	VB2_DEBUG("Preamble signature off end of preamble\n");
	return VB2_ERROR_PREAMBLE_SIG_OUTSIDE;
	}

	/* Make sure advertised signature data sizes are sane. */
	if (preamble->preamble_size < sig->data_size) {
	VB2_DEBUG("Signature calculated past end of the block\n");
	return VB2_ERROR_PREAMBLE_SIGNED_TOO_MUCH;
	}

	if (vb2_verify_data((const uint8_t *)preamble, size, sig, key, wb)) {
	VB2_DEBUG("Preamble signature validation failed\n");
	return VB2_ERROR_PREAMBLE_SIG_INVALID;
	}

	/* Verify we signed enough data */
	if (sig->data_size < sizeof(struct vb2_fw_preamble)) {
	VB2_DEBUG("Didn't sign enough data\n");
	return VB2_ERROR_PREAMBLE_SIGNED_TOO_LITTLE;
	}

	/* Verify body signature is inside the signed data */
	if (vb2_verify_signature_inside(preamble, sig->data_size,
	&preamble->body_signature)) {
	VB2_DEBUG("Firmware body signature off end of preamble\n");
	return VB2_ERROR_PREAMBLE_BODY_SIG_OUTSIDE;
	}

	/* Verify kernel subkey is inside the signed data */
	if (vb2_verify_packed_key_inside(preamble, sig->data_size,
	&preamble->kernel_subkey)) {
	VB2_DEBUG("Kernel subkey off end of preamble\n");
	return VB2_ERROR_PREAMBLE_KERNEL_SUBKEY_OUTSIDE;
	}

	/* Success */
	return VB2_SUCCESS;
	}