Add hwid digest field to GBB header

This adds a field in the GBB header to store the sha256 digest of
the HWID string, and updates gbb_utility so that it stores the
digest when it modifies the HWID. Because this is a new field,
the GBB_MINOR_VER is incremented.

BUG=chromium:415227
BRANCH=ToT
TEST=make runtests, VBOOT2=1 make runtests

Since the GBB is in the RO firmware, there should be no side
effects for existing devices (but even without that, they should
handle a minor version change without complaint).

Change-Id: Icdb2a0b564677b0b65e58df897d2ec5af3964998
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/221360
This commit is contained in:
Bill Richardson
2014-10-02 18:50:33 -07:00
committed by chrome-internal-fetch
parent 8bb3689d42
commit 6df3e33912
12 changed files with 132 additions and 14 deletions

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@@ -175,7 +175,7 @@ endif
# And a few more default utilities
LD = ${CC}
CXX ?= g++ # HEY: really?
CXX ?= g++
PKG_CONFIG ?= pkg-config
# Determine QEMU architecture needed, if any

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@@ -315,7 +315,8 @@ struct vb2_shared_data {
/* VB2 GBB struct version */
#define VB2_GBB_MAJOR_VER 1
#define VB2_GBB_MINOR_VER 1
#define VB2_GBB_MINOR_VER 2
/* v1.2 - added fields for sha256 digest of the HWID */
/* Flags for vb2_gbb_header.flags */
enum vb2_gbb_flag {
@@ -388,7 +389,13 @@ struct vb2_gbb_header {
uint32_t recovery_key_offset; /* Recovery key */
uint32_t recovery_key_size;
uint8_t pad[80]; /* To match GBB_HEADER_SIZE. Initialize to 0. */
/* Added in version 1.2 */
uint8_t hwid_digest[32]; /* sha256 */
uint8_t pad[48]; /* To match EXPECTED_GBB_HEADER_SIZE. Init to 0. */
} __attribute__((packed));
/* The GBB is used outside of vboot_reference, so this size is important. */
#define EXPECTED_GBB_HEADER_SIZE 128
#endif /* VBOOT_REFERENCE_VBOOT_2STRUCT_H_ */

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@@ -26,7 +26,8 @@
* return default values for those fields.
*/
#define GBB_MAJOR_VER 1
#define GBB_MINOR_VER 1
#define GBB_MINOR_VER 2
/* v1.2 - added field to hold sha256 digest of the HWID */
/* Maximum length of a HWID in bytes, counting terminating null. */
#define GBB_HWID_MAX_SIZE 256
@@ -86,8 +87,10 @@ typedef struct GoogleBinaryBlockHeader
uint32_t bmpfv_size;
uint32_t recovery_key_offset; /* Recovery key */
uint32_t recovery_key_size;
/* Added in version 1.2 */
uint8_t hwid_digest[32]; /* sha256 */
uint8_t pad[80]; /* To match GBB_HEADER_SIZE. Initialize to 0. */
uint8_t pad[48]; /* To match GBB_HEADER_SIZE. Initialize to 0. */
} __attribute__((packed)) GoogleBinaryBlockHeader;
#ifdef __cplusplus

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@@ -29,6 +29,7 @@ static void print_help(const char *prog)
"with following options:\n"
" --hwid \tReport hardware id (default).\n"
" --flags \tReport header flags.\n"
" --digest \tReport digest of hwid (>= v1.2)\n"
" -k, --rootkey=FILE \tFile name to export Root Key.\n"
" -b, --bmpfv=FILE \tFile name to export Bitmap FV.\n"
" -r --recoverykey=FILE\tFile name to export Recovery Key.\n"
@@ -55,6 +56,10 @@ static void print_help(const char *prog)
prog, prog, prog, prog);
}
enum {
OPT_DIGEST = 1000,
};
/* Command line options */
static const struct option long_opts[] = {
/* name hasarg *flag val */
@@ -67,6 +72,7 @@ static const struct option long_opts[] = {
{"recoverykey", 1, NULL, 'R'},
{"hwid", 2, NULL, 'i'},
{"flags", 2, NULL, 'L'},
{"digest", 0, NULL, OPT_DIGEST},
{NULL, 0, NULL, 0},
};
@@ -340,6 +346,7 @@ static int do_gbb_utility(int argc, char *argv[])
char *opt_hwid = NULL;
char *opt_flags = NULL;
int sel_hwid = 0;
int sel_digest = 0;
int sel_flags = 0;
uint8_t *inbuf = NULL;
off_t filesize;
@@ -386,6 +393,9 @@ static int do_gbb_utility(int argc, char *argv[])
opt_flags = optarg;
sel_flags = 1;
break;
case OPT_DIGEST:
sel_digest = 1;
break;
case '?':
errorcnt++;
if (optopt)
@@ -437,7 +447,7 @@ static int do_gbb_utility(int argc, char *argv[])
/* With no args, show the HWID */
if (!opt_rootkey && !opt_bmpfv && !opt_recoverykey
&& !sel_flags)
&& !sel_flags && !sel_digest)
sel_hwid = 1;
inbuf = read_entire_file(infile, &filesize);
@@ -457,6 +467,9 @@ static int do_gbb_utility(int argc, char *argv[])
gbb->hwid_size ? (char *)(gbb_base +
gbb->
hwid_offset) : "");
if (sel_digest)
print_hwid_digest(gbb, "digest: ", "\n");
if (sel_flags)
printf("flags: 0x%08x\n", gbb->flags);
if (opt_rootkey)
@@ -540,6 +553,7 @@ static int do_gbb_utility(int argc, char *argv[])
gbb->hwid_size);
strcpy((char *)(gbb_base + gbb->hwid_offset),
opt_hwid);
update_hwid_digest(gbb);
}
}

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@@ -141,8 +141,8 @@ int futil_cb_show_gbb(struct futil_traverse_state_s *state)
}
printf("GBB content:\n");
printf(" HWID: %s\n",
(const char *)(buf + gbb->hwid_offset));
printf(" HWID: %s\n", buf + gbb->hwid_offset);
print_hwid_digest(gbb, " digest: ", "\n");
pubkey = (VbPublicKey *)(buf + gbb->rootkey_offset);
if (PublicKeyLooksOkay(pubkey, gbb->rootkey_size)) {

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@@ -129,7 +129,7 @@ static void log_args(int argc, char *argv[])
log_open();
/* delimiter */
log_str(NULL, "##### HEY #####");
log_str(NULL, "##### LOG #####");
/* Can we tell who called us? */
parent = getppid();

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@@ -71,6 +71,14 @@ int futil_looks_like_gbb(GoogleBinaryBlockHeader *gbb, uint32_t len);
int futil_valid_gbb_header(GoogleBinaryBlockHeader *gbb, uint32_t len,
uint32_t *maxlen);
/* For GBB v1.2 and later, update the hwid_digest */
void update_hwid_digest(GoogleBinaryBlockHeader *gbb);
/* For GBB v1.2 and later, print the stored digest of the HWID (and whether
* it's correct). Return true if it is correct. */
int print_hwid_digest(GoogleBinaryBlockHeader *gbb,
const char *banner, const char *footer);
/* Copies a file or dies with an error message */
void futil_copy_file_or_die(const char *infile, const char *outfile);

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@@ -114,6 +114,57 @@ int futil_valid_gbb_header(GoogleBinaryBlockHeader *gbb, uint32_t len,
return 1;
}
/* For GBB v1.2 and later, print the stored digest of the HWID (and whether
* it's correct). Return true if it is correct. */
int print_hwid_digest(GoogleBinaryBlockHeader *gbb,
const char *banner, const char *footer)
{
printf("%s", banner);
/* There isn't one for v1.1 and earlier, so assume it's good. */
if (gbb->minor_version < 2) {
printf("<none>%s", footer);
return 1;
}
uint8_t *buf = (uint8_t *)gbb;
char *hwid_str = (char *)(buf + gbb->hwid_offset);
int is_valid = 0;
uint8_t* digest = DigestBuf(buf + gbb->hwid_offset,
strlen(hwid_str),
SHA256_DIGEST_ALGORITHM);
if (digest) {
int i;
is_valid = 1;
/* print it, comparing as we go */
for (i = 0; i < SHA256_DIGEST_SIZE; i++) {
printf("%02x", gbb->hwid_digest[i]);
if (gbb->hwid_digest[i] != digest[i])
is_valid = 0;
}
free(digest);
}
printf(" %s", is_valid ? "valid" : "<invalid>");
printf("%s", footer);
return is_valid;
}
/* For GBB v1.2 and later, update the hwid_digest field. */
void update_hwid_digest(GoogleBinaryBlockHeader *gbb)
{
/* There isn't one for v1.1 and earlier */
if (gbb->minor_version < 2)
return;
uint8_t *buf = (uint8_t *)gbb;
char *hwid_str = (char *)(buf + gbb->hwid_offset);
uint8_t* digest = DigestBuf(buf + gbb->hwid_offset,
strlen(hwid_str),
SHA256_DIGEST_ALGORITHM);
memcpy(gbb->hwid_digest, digest, SHA256_DIGEST_SIZE);
free(digest);
}
/*
* TODO: All sorts of race conditions likely here, and everywhere this is used.

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@@ -201,6 +201,33 @@ cat ${TMP}.blob | ${REPLACE} 0x2c 0x00 > ${TMP}.blob.bad
${FUTILITY} gbb_utility -g --recoverykey ${TMP}.read2 ${TMP}.blob.bad
if ${FUTILITY} gbb_utility -s --recoverykey ${TMP}.data2 ${TMP}.blob.bad; then false; fi
# GBB v1.2 adds a sha256 digest field in what was previously padding:
#
# hwid_digest: 0x0030 xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx
# 0x0040 xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx
# pad: 0x0050 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
# 0x0060 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
# 0x0070 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
# (HWID) 0x0080 30 31 32 33 34 35 36 37 38 39 41 42 43 44 45 00
# See that the digest is updated properly.
hwid="123456789ABCDEF"
${FUTILITY} gbb_utility -s -i ${hwid} ${TMP}.blob
expect=$(echo -n "$hwid" | sha256sum | cut -d ' ' -f 1)
[ $(echo -n ${expect} | wc -c) == "64" ]
${FUTILITY} gbb_utility -g --digest ${TMP}.blob | grep ${expect}
# Garble the digest, see that it's noticed.
# (assuming these zeros aren't present)
cat ${TMP}.blob | ${REPLACE} 0x33 0x00 0x00 0x00 0x00 0x00 > ${TMP}.blob.bad
${FUTILITY} gbb_utility -g --digest ${TMP}.blob.bad | grep '0000000000'
${FUTILITY} gbb_utility -g --digest ${TMP}.blob.bad | grep 'invalid'
# Garble the HWID. The digest is unchanged, but now invalid.
cat ${TMP}.blob | ${REPLACE} 0x84 0x70 0x71 0x72 > ${TMP}.blob.bad
${FUTILITY} gbb_utility -g --digest ${TMP}.blob.bad | grep 'invalid'
# cleanup
rm -f ${TMP}*
exit 0

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@@ -1,15 +1,19 @@
/*
* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
* 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.
*/
#include <stdio.h>
#include "gbb_header.h"
#include "test_common.h"
int main(int argc, char *argv[])
{
TEST_EQ(0, 0, "Not Really A");
TEST_EQ(sizeof(GoogleBinaryBlockHeader),
GBB_HEADER_SIZE,
"sizeof(GoogleBinaryBlockHeader)");
return !gTestSuccess;
TEST_EQ(0, 0, "Not Really A");
return !gTestSuccess;
}

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@@ -134,6 +134,10 @@ static void gbb_tests(void)
struct vb2_gbb_header gbbdest;
TEST_EQ(sizeof(struct vb2_gbb_header),
EXPECTED_GBB_HEADER_SIZE,
"sizeof(struct vb2_gbb_header)");
reset_common_data();
/* Good contents */

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@@ -499,7 +499,7 @@ namespace vboot_reference {
config_.header.minor_version = minor_version_;
config_.header.number_of_localizations = config_.localizations.size();
config_.header.number_of_screenlayouts = config_.localizations[0].size();
// HEY: this is part of the yaml consistency check
// NOTE: this is part of the yaml consistency check
for (unsigned int i = 1; i < config_.localizations.size(); ++i) {
assert(config_.header.number_of_screenlayouts ==
config_.localizations[i].size());