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/*
* Copyright 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 <ctype.h>
#include <getopt.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include "2sysincludes.h"
#include "2common.h"
#include "2sha.h"
#include "futility.h"
static const char usage[] = "\n"
"Usage: " MYNAME " %s [OPTIONS] DIGEST [...]\n"
"\n"
"This simulates a TPM PCR extension, to determine the expected output\n"
"\n"
"Each DIGEST arg should be a hex string (spaces optional) of the\n"
"appropriate length. The PCR is extended with each digest in turn\n"
"and the new value displayed.\n"
"\n"
"Options:\n"
" -i Initialize the PCR with the first DIGEST argument\n"
" (the default is to start with all zeros)\n"
" -2 Use sha256 DIGESTS (the default is sha1)\n"
"\n"
"Examples:\n"
"\n"
" " MYNAME " %s b52791126f96a21a8ba4d511c6f25a1c1eb6dc9e\n"
" " MYNAME " %s "
"'b5 27 91 12 6f 96 a2 1a 8b a4 d5 11 c6 f2 5a 1c 1e b6 dc 9e'\n"
"\n";
static void print_help(int argc, char *argv[])
{
printf(usage, argv[0], argv[0], argv[0]);
}
static int parse_hex(uint8_t *val, const char *str)
{
uint8_t v = 0;
char c;
int digit;
for (digit = 0; digit < 2; digit++) {
c = *str;
if (!c)
return 0;
if (!isxdigit(c))
return 0;
c = tolower(c);
if (c >= '0' && c <= '9')
v += c - '0';
else
v += 10 + c - 'a';
if (!digit)
v <<= 4;
str++;
}
*val = v;
return 1;
}
static void parse_digest_or_die(uint8_t *buf, int len, const char *str)
{
const char *s = str;
int i;
for (i = 0; i < len; i++) {
/* skip whitespace */
while (*s && isspace(*s))
s++;
if (!*s)
break;
if (!parse_hex(buf, s))
break;
/* on to the next byte */
s += 2;
buf++;
}
if (i != len) {
fprintf(stderr, "Invalid DIGEST \"%s\"\n", str);
exit(1);
}
}
static void print_digest(const uint8_t *buf, int len)
{
int i;
for (i = 0; i < len; i++)
printf("%02x", buf[i]);
}
enum {
OPT_HELP = 1000,
};
static const struct option long_opts[] = {
{"help", 0, 0, OPT_HELP},
{NULL, 0, 0, 0}
};
static int do_pcr(int argc, char *argv[])
{
uint8_t accum[VB2_MAX_DIGEST_SIZE * 2];
uint8_t pcr[VB2_MAX_DIGEST_SIZE];
int digest_alg = VB2_HASH_SHA1;
int digest_size;
int opt_init = 0;
int errorcnt = 0;
int i;
opterr = 0; /* quiet, you */
while ((i = getopt_long(argc, argv, ":i2", long_opts, NULL)) != -1) {
switch (i) {
case 'i':
opt_init = 1;
break;
case '2':
digest_alg = VB2_HASH_SHA256;
break;
case OPT_HELP:
print_help(argc, argv);
return !!errorcnt;
case '?':
if (optopt)
fprintf(stderr, "Unrecognized option: -%c\n",
optopt);
else
fprintf(stderr, "Unrecognized option\n");
errorcnt++;
break;
case ':':
fprintf(stderr, "Missing argument to -%c\n", optopt);
errorcnt++;
break;
default:
FATAL("Unrecognized getopt output: %d\n", i);
}
}
if (errorcnt) {
print_help(argc, argv);
return 1;
}
if (argc - optind < 1 + opt_init) {
fprintf(stderr, "You must extend at least one DIGEST\n");
print_help(argc, argv);
return 1;
}
memset(pcr, 0, sizeof(pcr));
digest_size = vb2_digest_size(digest_alg);
if (!digest_size) {
fprintf(stderr, "Error determining digest size!\n");
return 1;
}
if (opt_init) {
parse_digest_or_die(pcr, digest_size, argv[optind]);
optind++;
}
printf("PCR: ");
print_digest(pcr, digest_size);
printf("\n");
for (i = optind; i < argc; i++) {
memcpy(accum, pcr, sizeof(pcr));
parse_digest_or_die(accum + digest_size, digest_size, argv[i]);
printf(" + ");
print_digest(accum + digest_size, digest_size);
printf("\n");
if (VB2_SUCCESS != vb2_digest_buffer(accum, digest_size * 2,
digest_alg,
pcr, digest_size)) {
fprintf(stderr, "Error computing digest!\n");
return 1;
}
printf("PCR: ");
print_digest(pcr, digest_size);
printf("\n");
}
return 0;
}
DECLARE_FUTIL_COMMAND(pcr, do_pcr, VBOOT_VERSION_ALL,
"Simulate a TPM PCR extension operation");
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