blob: a09782ce5f296f68a298ffd8dbcd744e544c2123 [file] [log] [blame] [edit]
/* Copyright 2015 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.
*
* Some instances of the Chrome OS embedded controller firmware can't do a
* normal software sync handshake at boot, but will verify their own RW images
* instead. This is typically done by putting a struct vb2_packed_key in the RO
* image and a corresponding struct vb21_signature in the RW image.
*
* This file provides the basic implementation for that approach.
*/
#include <stdint.h>
#include <stdio.h>
#include <unistd.h>
#include "2common.h"
#include "2rsa.h"
#include "2sha.h"
#include "2sysincludes.h"
#include "file_type.h"
#include "fmap.h"
#include "futility.h"
#include "futility_options.h"
#include "host_common.h"
#include "host_common21.h"
#include "host_key21.h"
#include "host_misc.h"
#include "host_signature21.h"
#include "util_misc.h"
#define SIGNATURE_RSVD_SIZE 1024
#define EC_RW_FILENAME "EC_RW.bin"
static inline void vb2_print_bytes(const void *ptr, uint32_t len)
{
const uint8_t *buf = (const uint8_t *)ptr;
int i;
for (i = 0; i < len; i++)
printf("%02x", *buf++);
}
static void show_sig(const char *name, const struct vb21_signature *sig)
{
printf("Signature: %s\n", name);
printf(" Vboot API: 2.1\n");
printf(" Desc: \"%s\"\n", vb21_common_desc(sig));
printf(" Signature Algorithm: %d %s\n", sig->sig_alg,
vb2_get_sig_algorithm_name(sig->sig_alg));
printf(" Hash Algorithm: %d %s\n", sig->hash_alg,
vb2_get_hash_algorithm_name(sig->hash_alg));
printf(" Total size: %#x (%d)\n", sig->c.total_size,
sig->c.total_size);
printf(" ID: ");
vb2_print_bytes(&sig->id, sizeof(sig->id));
printf("\n");
printf(" Data size: %#x (%d)\n", sig->data_size,
sig->data_size);
}
int ft_show_rwsig(const char *name, uint8_t *buf, uint32_t len, void *nuthin)
{
const struct vb21_signature *sig = 0;
const struct vb21_packed_key *pkey = show_option.pkey;
struct vb2_public_key key;
uint8_t workbuf[VB2_VERIFY_DATA_WORKBUF_BYTES]
__attribute__((aligned(VB2_WORKBUF_ALIGN)));
struct vb2_workbuf wb;
uint32_t data_size, sig_size = SIGNATURE_RSVD_SIZE;
uint32_t total_data_size = 0;
uint8_t *data;
FmapHeader *fmap;
int i;
VB2_DEBUG("name %s len 0x%08x (%d)\n", name, len, len);
/* Am I just looking at a signature file? */
VB2_DEBUG("Looking for signature at 0x0\n");
sig = (const struct vb21_signature *)buf;
if (VB2_SUCCESS == vb21_verify_signature(sig, len)) {
show_sig(name, sig);
if (!show_option.fv) {
printf("No data available to verify\n");
return show_option.strict;
}
data = show_option.fv;
data_size = show_option.fv_size;
total_data_size = show_option.fv_size;
} else if ((fmap = fmap_find(buf, len))) {
/* This looks like a full image. */
FmapAreaHeader *fmaparea;
VB2_DEBUG("Found an FMAP!\n");
/* If no public key is provided, use the one packed in RO
* image, and print that. */
if (!pkey) {
pkey = (const struct vb21_packed_key *)
fmap_find_by_name(buf, len, fmap, "KEY_RO", 0);
if (pkey)
ft_show_vb21_pubkey(name, (uint8_t *)pkey,
pkey->c.total_size, NULL);
}
sig = (const struct vb21_signature *)
fmap_find_by_name(buf, len, fmap, "SIG_RW", &fmaparea);
if (!sig) {
VB2_DEBUG("No SIG_RW in FMAP.\n");
return 1;
}
sig_size = fmaparea->area_size;
VB2_DEBUG("Looking for signature at %#tx (%#x)\n",
(uint8_t*)sig - buf, sig_size);
if (VB2_SUCCESS != vb21_verify_signature(sig, sig_size))
return 1;
show_sig(name, sig);
data = fmap_find_by_name(buf, len, fmap, "EC_RW", &fmaparea);
data_size = sig->data_size;
/*
* TODO(crosbug.com/p/62231): EC_RW region should not include
* the signature.
*/
total_data_size = fmaparea->area_size-sig_size;
if (!data) {
VB2_DEBUG("No EC_RW in FMAP.\n");
return 1;
}
} else {
/* Or maybe this is just the RW portion, that does not
* contain a FMAP. */
if (show_option.sig_size)
sig_size = show_option.sig_size;
VB2_DEBUG("Looking for signature at %#x\n", len - sig_size);
if (len < sig_size) {
VB2_DEBUG("File is too small\n");
return 1;
}
sig = (const struct vb21_signature *)(buf + len - sig_size);
if (VB2_SUCCESS == vb21_verify_signature(sig, sig_size)) {
show_sig(name, sig);
data = buf;
data_size = sig->data_size;
total_data_size = len - sig_size;
} else {
return 1;
}
}
if (!pkey) {
printf("No public key available to verify with\n");
return show_option.strict;
}
/* We already did this once, so it should work again */
if (vb21_unpack_key(&key,
(const uint8_t *)pkey,
pkey->c.total_size)) {
VB2_DEBUG("Can't unpack pubkey\n");
return 1;
}
if (data_size > total_data_size) {
VB2_DEBUG("Invalid signature data_size: bigger than total area size.\n");
return 1;
}
/* The sig is destroyed by the verify operation, so make a copy */
{
uint8_t sigbuf[sig->c.total_size];
memcpy(sigbuf, sig, sizeof(sigbuf));
vb2_workbuf_init(&wb, workbuf, sizeof(workbuf));
if (vb21_verify_data(data, data_size,
(struct vb21_signature *)sigbuf,
(const struct vb2_public_key *)&key,
&wb)) {
fprintf(stderr, "Signature verification failed\n");
return 1;
}
}
/* Check that the rest of region is padded with 0xff. */
for (i = data_size; i < total_data_size; i++) {
if (data[i] != 0xff) {
fprintf(stderr, "Padding verification failed\n");
return 1;
}
}
printf("Signature verification succeeded.\n");
return 0;
}
int ft_sign_rwsig(const char *name, uint8_t *buf, uint32_t len, void *nuthin)
{
struct vb21_signature *tmp_sig = 0;
struct vb2_public_key *pubkey = 0;
struct vb21_packed_key *packedkey = 0;
uint8_t *keyb_data = 0;
uint32_t keyb_size;
uint8_t* data = buf; /* data to be signed */
uint32_t r, data_size = len, sig_size = SIGNATURE_RSVD_SIZE;
int retval = 1;
FmapHeader *fmap = NULL;
FmapAreaHeader *fmaparea;
struct vb21_signature *old_sig = 0;
VB2_DEBUG("name %s len 0x%08x (%d)\n", name, len, len);
/* If we don't have a distinct OUTFILE, look for an existing sig */
if (sign_option.inout_file_count < 2) {
fmap = fmap_find(buf, len);
if (fmap) {
/* This looks like a full image. */
VB2_DEBUG("Found an FMAP!\n");
old_sig = (struct vb21_signature *)
fmap_find_by_name(buf, len, fmap, "SIG_RW",
&fmaparea);
if (!old_sig) {
VB2_DEBUG("No SIG_RW in FMAP.\n");
goto done;
}
sig_size = fmaparea->area_size;
VB2_DEBUG("Looking for signature at %#tx (%#x)\n",
(uint8_t*)old_sig - buf, sig_size);
data = fmap_find_by_name(buf, len, fmap, "EC_RW",
&fmaparea);
if (!data) {
VB2_DEBUG("No EC_RW in FMAP.\n");
goto done;
}
} else {
/* Or maybe this is just the RW portion, that does not
* contain a FMAP. */
if (sign_option.sig_size)
sig_size = sign_option.sig_size;
VB2_DEBUG("Looking for old signature at %#x\n",
len - sig_size);
if (len < sig_size) {
fprintf(stderr, "File is too small\n");
goto done;
}
/* Take a look */
old_sig = (struct vb21_signature *)
(buf + len - sig_size);
}
if (vb21_verify_signature(old_sig, sig_size)) {
fprintf(stderr, "Can't find a valid signature\n");
goto done;
}
/* Use the same extent again */
data_size = old_sig->data_size;
VB2_DEBUG("Found sig: data_size is %#x (%d)\n", data_size,
data_size);
}
/* Unless overridden */
if (sign_option.data_size)
data_size = sign_option.data_size;
/* Sign the blob */
if (sign_option.prikey) {
r = vb21_sign_data(&tmp_sig,
data, data_size, sign_option.prikey, 0);
if (r) {
fprintf(stderr,
"Unable to sign data (error 0x%08x)\n", r);
goto done;
}
} else {
VB2_DEBUG("Private key not provided. Copying previous signature\n");
if (!old_sig) {
/* This isn't necessary because no prikey mode runs only
* for fmap input or RW input */
fprintf(stderr, "Previous signature not found.\n");
goto done;
}
tmp_sig = calloc(1, old_sig->c.total_size);
if (!tmp_sig)
goto done;
memcpy(tmp_sig, old_sig, old_sig->c.total_size);
}
if (sign_option.inout_file_count < 2) {
/* Overwrite the old signature */
if (tmp_sig->c.total_size > sig_size) {
fprintf(stderr, "New sig is too large (%d > %d)\n",
tmp_sig->c.total_size, sig_size);
goto done;
}
VB2_DEBUG("Replacing old signature with new one\n");
memset(old_sig, 0xff, sig_size);
memcpy(old_sig, tmp_sig, tmp_sig->c.total_size);
if (fmap) {
VB2_DEBUG("Writing %s (size=%d)\n",
EC_RW_FILENAME, fmaparea->area_size);
if (vb2_write_file(EC_RW_FILENAME,
data, fmaparea->area_size))
goto done;
}
} else {
/* Write the signature to a new file */
r = vb21_write_object(sign_option.outfile, tmp_sig);
if (r) {
fprintf(stderr, "Unable to write sig"
" (error 0x%08x, if that helps)\n", r);
goto done;
}
}
/* For full images, let's replace the public key in RO. If prikey is
* not provided, skip it. */
if (fmap && sign_option.prikey) {
uint8_t *new_pubkey;
uint8_t *pubkey_buf = 0;
/* Create the public key */
if (vb2_public_key_alloc(&pubkey,
sign_option.prikey->sig_alg)) {
fprintf(stderr, "Unable to allocate the public key\n");
goto done;
}
/* Extract the keyb blob */
if (vb_keyb_from_rsa(sign_option.prikey->rsa_private_key,
&keyb_data, &keyb_size)) {
fprintf(stderr, "Couldn't extract the public key\n");
goto done;
}
/*
* Copy the keyb blob to the public key's buffer, because that's
* where vb2_unpack_key_data() and vb2_public_key_pack() expect
* to find it.
*/
pubkey_buf = vb2_public_key_packed_data(pubkey);
memcpy(pubkey_buf, keyb_data, keyb_size);
/* Fill in the internal struct pointers */
if (vb2_unpack_key_data(pubkey, pubkey_buf, keyb_size)) {
fprintf(stderr, "Unable to unpack the public key blob\n");
goto done;
}
pubkey->hash_alg = sign_option.prikey->hash_alg;
pubkey->version = sign_option.version_specified ?
sign_option.version : 1;
vb2_public_key_set_desc(pubkey, sign_option.prikey->desc);
memcpy((struct vb2_id *)pubkey->id, &sign_option.prikey->id,
sizeof(*(pubkey->id)));
if (vb21_public_key_pack(&packedkey, pubkey)) {
goto done;
}
new_pubkey = fmap_find_by_name(buf, len, fmap, "KEY_RO",
&fmaparea);
if (!new_pubkey) {
VB2_DEBUG("No KEY_RO in FMAP.\n");
goto done;
}
/* Overwrite the old signature */
if (packedkey->c.total_size > fmaparea->area_size) {
fprintf(stderr, "New sig is too large (%d > %d)\n",
packedkey->c.total_size, sig_size);
goto done;
}
memset(new_pubkey, 0xff, fmaparea->area_size);
memcpy(new_pubkey, packedkey, packedkey->c.total_size);
}
/* Finally */
retval = 0;
done:
if (tmp_sig)
free(tmp_sig);
if (pubkey)
vb2_public_key_free(pubkey);
if (packedkey)
free(packedkey);
if (keyb_data)
free(keyb_data);
return retval;
}
enum futil_file_type ft_recognize_rwsig(uint8_t *buf, uint32_t len)
{
FmapHeader *fmap;
const struct vb21_signature *sig = NULL;
uint32_t sig_size;
if (!vb21_verify_signature((const struct vb21_signature *)buf, len))
return FILE_TYPE_RWSIG;
fmap = fmap_find(buf, len);
if (fmap) {
/* This looks like a full image. */
FmapAreaHeader *fmaparea;
sig = (const struct vb21_signature *)
fmap_find_by_name(buf, len, fmap, "SIG_RW", &fmaparea);
if (!sig)
return FILE_TYPE_UNKNOWN;
sig_size = fmaparea->area_size;
} else {
/* RW-only image */
sig = (const struct vb21_signature *)
(buf + len - SIGNATURE_RSVD_SIZE);
sig_size = SIGNATURE_RSVD_SIZE;
}
if (len >= sig_size && !vb21_verify_signature(sig, sig_size))
return FILE_TYPE_RWSIG;
return FILE_TYPE_UNKNOWN;
}