host/lib/host_common.c

/* Copyright (c) 2011 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.
 *
 * Host functions for verified boot.
 */

/* TODO: change all 'return 0', 'return 1' into meaningful return codes */
#include <string.h>

#include "host_common.h"

#include "cryptolib.h"
#include "utility.h"
#include "vboot_common.h"

VbECPreambleHeader* CreateECPreamble(
    uint64_t firmware_version,
    const VbSignature* body_digest,
    const VbPrivateKey* signing_key,
    uint32_t flags,
    const char* name) {

  VbECPreambleHeader* h;
  uint64_t signed_size = (sizeof(VbECPreambleHeader) + body_digest->sig_size);
  uint64_t block_size = signed_size + siglen_map[signing_key->algorithm];
  uint8_t* body_digest_dest;
  uint8_t* block_sig_dest;
  VbSignature *sigtmp;

  /* Allocate key block */
  h = (VbECPreambleHeader*)malloc(block_size);
  if (!h)
    return NULL;
  Memset(h, 0, block_size);
  body_digest_dest = (uint8_t*)(h + 1);
  block_sig_dest = body_digest_dest + body_digest->sig_size;

  h->header_version_major = EC_PREAMBLE_HEADER_VERSION_MAJOR;
  h->header_version_minor = EC_PREAMBLE_HEADER_VERSION_MINOR;
  h->preamble_size = block_size;
  h->firmware_version = firmware_version;
  h->flags = flags;
  if (name)
    strncpy(h->name, name, sizeof(h->name));

  /* Copy body hash */
  SignatureInit(&h->body_digest, body_digest_dest,
                body_digest->sig_size, 0);
  SignatureCopy(&h->body_digest, body_digest);

  /* Set up signature struct so we can calculate the signature */
  SignatureInit(&h->preamble_signature, block_sig_dest,
                siglen_map[signing_key->algorithm], signed_size);

  /* Calculate signature */
  sigtmp = CalculateSignature((uint8_t*)h, signed_size, signing_key);
  SignatureCopy(&h->preamble_signature, sigtmp);
  free(sigtmp);

  /* Return the header */
  return h;
}

VbFirmwarePreambleHeader* CreateFirmwarePreamble(
    uint64_t firmware_version,
    const VbPublicKey* kernel_subkey,
    const VbSignature* body_signature,
    const VbPrivateKey* signing_key,
    uint32_t flags) {

  VbFirmwarePreambleHeader* h;
  uint64_t signed_size = (sizeof(VbFirmwarePreambleHeader) +
                          kernel_subkey->key_size +
                          body_signature->sig_size);
  uint64_t block_size = signed_size + siglen_map[signing_key->algorithm];
  uint8_t* kernel_subkey_dest;
  uint8_t* body_sig_dest;
  uint8_t* block_sig_dest;
  VbSignature *sigtmp;

  /* Allocate key block */
  h = (VbFirmwarePreambleHeader*)malloc(block_size);
  if (!h)
    return NULL;
  Memset(h, 0, block_size);
  kernel_subkey_dest = (uint8_t*)(h + 1);
  body_sig_dest = kernel_subkey_dest + kernel_subkey->key_size;
  block_sig_dest = body_sig_dest + body_signature->sig_size;

  h->header_version_major = FIRMWARE_PREAMBLE_HEADER_VERSION_MAJOR;
  h->header_version_minor = FIRMWARE_PREAMBLE_HEADER_VERSION_MINOR;
  h->preamble_size = block_size;
  h->firmware_version = firmware_version;
  h->flags = flags;

  /* Copy data key */
  PublicKeyInit(&h->kernel_subkey, kernel_subkey_dest,
                kernel_subkey->key_size);
  PublicKeyCopy(&h->kernel_subkey, kernel_subkey);

  /* Copy body signature */
  SignatureInit(&h->body_signature, body_sig_dest,
                body_signature->sig_size, 0);
  SignatureCopy(&h->body_signature, body_signature);

  /* Set up signature struct so we can calculate the signature */
  SignatureInit(&h->preamble_signature, block_sig_dest,
                siglen_map[signing_key->algorithm], signed_size);

  /* Calculate signature */
  sigtmp = CalculateSignature((uint8_t*)h, signed_size, signing_key);
  SignatureCopy(&h->preamble_signature, sigtmp);
  free(sigtmp);

  /* Return the header */
  return h;
}


/* Creates a kernel preamble, signed with [signing_key].
 * Caller owns the returned pointer, and must free it with free().
 *
 * Returns NULL if error. */
VbKernelPreambleHeader* CreateKernelPreamble(
    uint64_t kernel_version,
    uint64_t body_load_address,
    uint64_t bootloader_address,
    uint64_t bootloader_size,
    const VbSignature* body_signature,
    uint64_t desired_size,
    const VbPrivateKey* signing_key) {

  VbKernelPreambleHeader* h;
  uint64_t signed_size = (sizeof(VbKernelPreambleHeader) +
                          body_signature->sig_size);
  uint64_t block_size = signed_size + siglen_map[signing_key->algorithm];
  uint8_t* body_sig_dest;
  uint8_t* block_sig_dest;
  VbSignature *sigtmp;

  /* If the block size is smaller than the desired size, pad it */
  if (block_size < desired_size)
    block_size = desired_size;

  /* Allocate key block */
  h = (VbKernelPreambleHeader*)malloc(block_size);
  Memset(h, 0, block_size);

  if (!h)
    return NULL;
  body_sig_dest = (uint8_t*)(h + 1);
  block_sig_dest = body_sig_dest + body_signature->sig_size;

  h->header_version_major = KERNEL_PREAMBLE_HEADER_VERSION_MAJOR;
  h->header_version_minor = KERNEL_PREAMBLE_HEADER_VERSION_MINOR;
  h->preamble_size = block_size;
  h->kernel_version = kernel_version;
  h->body_load_address = body_load_address;
  h->bootloader_address = bootloader_address;
  h->bootloader_size = bootloader_size;

  /* Copy body signature */
  SignatureInit(&h->body_signature, body_sig_dest,
                body_signature->sig_size, 0);
  SignatureCopy(&h->body_signature, body_signature);

  /* Set up signature struct so we can calculate the signature */
  SignatureInit(&h->preamble_signature, block_sig_dest,
                siglen_map[signing_key->algorithm], signed_size);

  /* Calculate signature */
  sigtmp = CalculateSignature((uint8_t*)h, signed_size, signing_key);
  SignatureCopy(&h->preamble_signature, sigtmp);
  free(sigtmp);

  /* Return the header */
  return h;
}