Bill Richardson | f4f395e | 2014-10-22 17:42:20 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2014 The Chromium OS Authors. All rights reserved. |
| 3 | * Use of this source code is governed by a BSD-style license that can be |
| 4 | * found in the LICENSE file. |
| 5 | */ |
| 6 | |
| 7 | #include <ctype.h> |
| 8 | #include <getopt.h> |
| 9 | #include <stdint.h> |
| 10 | #include <stdio.h> |
| 11 | #include <string.h> |
| 12 | |
| 13 | #include "futility.h" |
| 14 | |
| 15 | static const char usage[] = "\n" |
| 16 | "Usage: " MYNAME " %s [OPTIONS] DIGEST [...]\n" |
| 17 | "\n" |
| 18 | "This simulates a TPM PCR extension, to determine the expected output\n" |
| 19 | "\n" |
| 20 | "Each DIGEST arg should be a hex string (spaces optional) of the\n" |
| 21 | "appropriate length. The PCR is extended with each digest in turn\n" |
| 22 | "and the new value displayed.\n" |
| 23 | "\n" |
| 24 | "Options:\n" |
| 25 | " -i Initialize the PCR with the first DIGEST argument\n" |
| 26 | " (the default is to start with all zeros)\n" |
| 27 | " -2 Use sha256 DIGESTS (the default is sha1)\n" |
| 28 | "\n" |
| 29 | "Examples:\n" |
| 30 | "\n" |
| 31 | " " MYNAME " %s b52791126f96a21a8ba4d511c6f25a1c1eb6dc9e\n" |
| 32 | " " MYNAME " %s " |
| 33 | "'b5 27 91 12 6f 96 a2 1a 8b a4 d5 11 c6 f2 5a 1c 1e b6 dc 9e'\n" |
| 34 | "\n"; |
| 35 | |
| 36 | static void help_and_quit(const char *prog) |
| 37 | { |
| 38 | printf(usage, prog, prog, prog); |
| 39 | } |
| 40 | |
| 41 | static int parse_hex(uint8_t *val, const char *str) |
| 42 | { |
| 43 | uint8_t v = 0; |
| 44 | char c; |
| 45 | int digit; |
| 46 | |
| 47 | for (digit = 0; digit < 2; digit++) { |
| 48 | c = *str; |
| 49 | if (!c) |
| 50 | return 0; |
| 51 | if (!isxdigit(c)) |
| 52 | return 0; |
| 53 | c = tolower(c); |
| 54 | if (c >= '0' && c <= '9') |
| 55 | v += c - '0'; |
| 56 | else |
| 57 | v += 10 + c - 'a'; |
| 58 | if (!digit) |
| 59 | v <<= 4; |
| 60 | str++; |
| 61 | } |
| 62 | |
| 63 | *val = v; |
| 64 | return 1; |
| 65 | } |
| 66 | |
| 67 | static void parse_digest_or_die(uint8_t *buf, int len, const char *str) |
| 68 | { |
| 69 | const char *s = str; |
| 70 | int i; |
| 71 | |
| 72 | for (i = 0; i < len; i++) { |
| 73 | /* skip whitespace */ |
| 74 | while (*s && isspace(*s)) |
| 75 | s++; |
| 76 | if (!*s) |
| 77 | break; |
| 78 | if (!parse_hex(buf, s)) |
| 79 | break; |
| 80 | |
| 81 | /* on to the next byte */ |
| 82 | s += 2; |
| 83 | buf++; |
| 84 | } |
| 85 | |
| 86 | if (i != len) { |
| 87 | fprintf(stderr, "Invalid DIGEST \"%s\"\n", str); |
| 88 | exit(1); |
| 89 | } |
| 90 | } |
| 91 | |
| 92 | static void print_digest(const uint8_t *buf, int len) |
| 93 | { |
| 94 | int i; |
| 95 | for (i = 0; i < len; i++) |
| 96 | printf("%02x", buf[i]); |
| 97 | } |
| 98 | |
| 99 | |
| 100 | static int do_pcr(int argc, char *argv[]) |
| 101 | { |
| 102 | uint8_t accum[SHA256_DIGEST_SIZE * 2]; |
| 103 | uint8_t pcr[SHA256_DIGEST_SIZE]; |
| 104 | int digest_alg = SHA1_DIGEST_ALGORITHM; |
| 105 | int digest_size = SHA1_DIGEST_SIZE; |
| 106 | int opt_init = 0; |
| 107 | int errorcnt = 0; |
| 108 | uint8_t *digest; |
| 109 | int i; |
| 110 | |
| 111 | opterr = 0; /* quiet, you */ |
| 112 | while ((i = getopt(argc, argv, ":i2")) != -1) { |
| 113 | switch (i) { |
| 114 | case 'i': |
| 115 | opt_init = 1; |
| 116 | break; |
| 117 | case '2': |
| 118 | digest_alg = SHA256_DIGEST_ALGORITHM; |
| 119 | digest_size = SHA256_DIGEST_SIZE; |
| 120 | break; |
| 121 | case '?': |
| 122 | if (optopt) |
| 123 | fprintf(stderr, "Unrecognized option: -%c\n", |
| 124 | optopt); |
| 125 | else |
| 126 | fprintf(stderr, "Unrecognized option\n"); |
| 127 | errorcnt++; |
| 128 | break; |
| 129 | case ':': |
| 130 | fprintf(stderr, "Missing argument to -%c\n", optopt); |
| 131 | errorcnt++; |
| 132 | break; |
| 133 | default: |
| 134 | DIE; |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | if (errorcnt) { |
| 139 | help_and_quit(argv[0]); |
| 140 | return 1; |
| 141 | } |
| 142 | |
| 143 | if (argc - optind < 1 + opt_init) { |
| 144 | fprintf(stderr, "You must extend at least one DIGEST\n"); |
| 145 | help_and_quit(argv[0]); |
| 146 | return 1; |
| 147 | } |
| 148 | |
| 149 | memset(pcr, 0, sizeof(pcr)); |
| 150 | |
| 151 | if (opt_init) { |
| 152 | parse_digest_or_die(pcr, digest_size, argv[optind]); |
| 153 | optind++; |
| 154 | } |
| 155 | |
| 156 | printf("PCR: "); |
| 157 | print_digest(pcr, digest_size); |
| 158 | printf("\n"); |
| 159 | |
| 160 | for (i = optind; i < argc; i++) { |
| 161 | memcpy(accum, pcr, sizeof(pcr)); |
| 162 | parse_digest_or_die(accum + digest_size, digest_size, argv[i]); |
| 163 | |
| 164 | printf(" + "); |
| 165 | print_digest(accum + digest_size, digest_size); |
| 166 | printf("\n"); |
| 167 | |
| 168 | digest = DigestBuf(accum, digest_size * 2, digest_alg); |
| 169 | if (!digest) { |
| 170 | fprintf(stderr, "Error computing digest!\n"); |
| 171 | return 1; |
| 172 | } |
| 173 | memcpy(pcr, digest, digest_size); |
| 174 | free(digest); |
| 175 | |
| 176 | printf("PCR: "); |
| 177 | print_digest(pcr, digest_size); |
| 178 | printf("\n"); |
| 179 | } |
| 180 | |
| 181 | return 0; |
| 182 | } |
| 183 | |
| 184 | DECLARE_FUTIL_COMMAND(pcr, do_pcr, |
| 185 | "Simulate a TPM PCR extension operation", |
| 186 | help_and_quit); |