boot: add new pcrphase tool to measure barrier strings into PCR 11
This commit is contained in:
Lennart Poettering
@@ -0,0 +1,262 @@
|
||||
/* SPDX-License-Identifier: LGPL-2.1-or-later */
|
||||
|
||||
#include <getopt.h>
|
||||
|
||||
#include <sd-messages.h>
|
||||
|
||||
#include "efivars.h"
|
||||
#include "main-func.h"
|
||||
#include "openssl-util.h"
|
||||
#include "parse-util.h"
|
||||
#include "pretty-print.h"
|
||||
#include "tpm-pcr.h"
|
||||
#include "tpm2-util.h"
|
||||
|
||||
static char *arg_tpm2_device = NULL;
|
||||
static char **arg_banks = NULL;
|
||||
|
||||
STATIC_DESTRUCTOR_REGISTER(arg_banks, strv_freep);
|
||||
STATIC_DESTRUCTOR_REGISTER(arg_tpm2_device, freep);
|
||||
|
||||
static int help(int argc, char *argv[], void *userdata) {
|
||||
_cleanup_free_ char *link = NULL;
|
||||
int r;
|
||||
|
||||
r = terminal_urlify_man("systemd-pcrphase", "1", &link);
|
||||
if (r < 0)
|
||||
return log_oom();
|
||||
|
||||
printf("%1$s [OPTIONS...] COMMAND ...\n"
|
||||
"\n%5$sMeasure boot phase into TPM2 PCR 11.%6$s\n"
|
||||
"\n%3$sOptions:%4$s\n"
|
||||
" -h --help Show this help\n"
|
||||
" --version Print version\n"
|
||||
" --bank=DIGEST Select TPM bank (SHA1, SHA256)\n"
|
||||
" --tpm2-device=PATH Use specified TPM2 device\n"
|
||||
"\nSee the %2$s for details.\n",
|
||||
program_invocation_short_name,
|
||||
link,
|
||||
ansi_underline(),
|
||||
ansi_normal(),
|
||||
ansi_highlight(),
|
||||
ansi_normal());
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int parse_argv(int argc, char *argv[]) {
|
||||
enum {
|
||||
ARG_VERSION = 0x100,
|
||||
ARG_BANK,
|
||||
ARG_TPM2_DEVICE,
|
||||
};
|
||||
|
||||
static const struct option options[] = {
|
||||
{ "help", no_argument, NULL, 'h' },
|
||||
{ "version", no_argument, NULL, ARG_VERSION },
|
||||
{ "bank", required_argument, NULL, ARG_BANK },
|
||||
{ "tpm2-device", required_argument, NULL, ARG_TPM2_DEVICE },
|
||||
{}
|
||||
};
|
||||
|
||||
int c;
|
||||
|
||||
assert(argc >= 0);
|
||||
assert(argv);
|
||||
|
||||
while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
|
||||
switch (c) {
|
||||
|
||||
case 'h':
|
||||
help(0, NULL, NULL);
|
||||
return 0;
|
||||
|
||||
case ARG_VERSION:
|
||||
return version();
|
||||
|
||||
case ARG_BANK: {
|
||||
const EVP_MD *implementation;
|
||||
|
||||
implementation = EVP_get_digestbyname(optarg);
|
||||
if (!implementation)
|
||||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Unknown bank '%s', refusing.", optarg);
|
||||
|
||||
if (strv_extend(&arg_banks, EVP_MD_name(implementation)) < 0)
|
||||
return log_oom();
|
||||
|
||||
break;
|
||||
}
|
||||
|
||||
case ARG_TPM2_DEVICE: {
|
||||
_cleanup_free_ char *device = NULL;
|
||||
|
||||
if (streq(optarg, "list"))
|
||||
return tpm2_list_devices();
|
||||
|
||||
if (!streq(optarg, "auto")) {
|
||||
device = strdup(optarg);
|
||||
if (!device)
|
||||
return log_oom();
|
||||
}
|
||||
|
||||
free_and_replace(arg_tpm2_device, device);
|
||||
break;
|
||||
}
|
||||
|
||||
case '?':
|
||||
return -EINVAL;
|
||||
|
||||
default:
|
||||
assert_not_reached();
|
||||
}
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
static int determine_banks(struct tpm2_context *c) {
|
||||
_cleanup_free_ TPMI_ALG_HASH *algs = NULL;
|
||||
int n_algs, r;
|
||||
|
||||
assert(c);
|
||||
|
||||
if (!strv_isempty(arg_banks)) /* Explicitly configured? Then use that */
|
||||
return 0;
|
||||
|
||||
n_algs = tpm2_get_good_pcr_banks(c->esys_context, UINT32_C(1) << TPM_PCR_INDEX_KERNEL_IMAGE, &algs);
|
||||
if (n_algs <= 0)
|
||||
return n_algs;
|
||||
|
||||
for (int i = 0; i < n_algs; i++) {
|
||||
const EVP_MD *implementation;
|
||||
const char *salg;
|
||||
|
||||
salg = tpm2_pcr_bank_to_string(algs[i]);
|
||||
if (!salg)
|
||||
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE), "TPM2 operates with unknown PCR algorithm, can't measure.");
|
||||
|
||||
implementation = EVP_get_digestbyname(salg);
|
||||
if (!implementation)
|
||||
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE), "TPM2 operates with unsupported PCR algorithm, can't measure.");
|
||||
|
||||
r = strv_extend(&arg_banks, EVP_MD_name(implementation));
|
||||
if (r < 0)
|
||||
return log_oom();
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int run(int argc, char *argv[]) {
|
||||
_cleanup_(tpm2_context_destroy) struct tpm2_context c = {};
|
||||
_cleanup_free_ char *joined = NULL, *pcr_string = NULL;
|
||||
const char *word;
|
||||
unsigned pcr_nr;
|
||||
size_t length;
|
||||
TSS2_RC rc;
|
||||
int r;
|
||||
|
||||
log_setup();
|
||||
|
||||
r = parse_argv(argc, argv);
|
||||
if (r <= 0)
|
||||
return r;
|
||||
|
||||
if (optind+1 != argc)
|
||||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Expected a single argument.");
|
||||
|
||||
word = argv[optind];
|
||||
|
||||
/* Refuse to measure an empty word. We want to be able to write the series of measured words
|
||||
* separated by colons, where multiple separating colons are collapsed. Thus it makes sense to
|
||||
* disallow an empty word to avoid ambiguities. */
|
||||
if (isempty(word))
|
||||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "String to measure cannot be empty, refusing.");
|
||||
|
||||
length = strlen(word);
|
||||
|
||||
/* Skip logic if sd-stub is not used, after all PCR 11 might have a very different purpose then. */
|
||||
r = efi_get_variable_string(EFI_LOADER_VARIABLE(StubPcrKernelImage), &pcr_string);
|
||||
if (r == -ENOENT) {
|
||||
log_info("Kernel stub did not measure kernel image into PCR %u, skipping measurement.", TPM_PCR_INDEX_KERNEL_IMAGE);
|
||||
return EXIT_SUCCESS;
|
||||
}
|
||||
if (r < 0)
|
||||
return log_error_errno(r, "Failed to read StubPcrKernelImage EFI variable: %m");
|
||||
|
||||
/* Let's validate that the stub announced PCR 11 as we expected. */
|
||||
r = safe_atou(pcr_string, &pcr_nr);
|
||||
if (r < 0)
|
||||
return log_error_errno(r, "Failed to parse StubPcrKernelImage EFI variable: %s", pcr_string);
|
||||
if (pcr_nr != TPM_PCR_INDEX_KERNEL_IMAGE)
|
||||
return log_error_errno(SYNTHETIC_ERRNO(EREMOTE), "Kernel stub measured kernel image into PCR %u, which is different than expected %u.", pcr_nr, TPM_PCR_INDEX_KERNEL_IMAGE);
|
||||
|
||||
r = dlopen_tpm2();
|
||||
if (r < 0)
|
||||
return log_error_errno(r, "Failed to load TPM2 libraries: %m");
|
||||
|
||||
r = tpm2_context_init(arg_tpm2_device, &c);
|
||||
if (r < 0)
|
||||
return r;
|
||||
|
||||
r = determine_banks(&c);
|
||||
if (r < 0)
|
||||
return r;
|
||||
if (strv_isempty(arg_banks)) /* Still none? */
|
||||
return log_error_errno(SYNTHETIC_ERRNO(ENOENT), "Found a TPM2 without enabled PCR banks. Can't operate.");
|
||||
|
||||
TPML_DIGEST_VALUES values = {};
|
||||
STRV_FOREACH(bank, arg_banks) {
|
||||
const EVP_MD *implementation;
|
||||
int id;
|
||||
|
||||
assert_se(implementation = EVP_get_digestbyname(*bank));
|
||||
|
||||
if (values.count >= ELEMENTSOF(values.digests))
|
||||
return log_error_errno(SYNTHETIC_ERRNO(E2BIG), "Too many banks selected.");
|
||||
|
||||
if ((size_t) EVP_MD_size(implementation) > sizeof(values.digests[values.count].digest))
|
||||
return log_error_errno(SYNTHETIC_ERRNO(E2BIG), "Hash result too large for TPM2.");
|
||||
|
||||
id = tpm2_pcr_bank_from_string(EVP_MD_name(implementation));
|
||||
if (id < 0)
|
||||
return log_error_errno(id, "Can't map hash name to TPM2.");
|
||||
|
||||
values.digests[values.count].hashAlg = id;
|
||||
|
||||
if (EVP_Digest(word, length, (unsigned char*) &values.digests[values.count].digest, NULL, implementation, NULL) != 1)
|
||||
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE), "Failed to hash word.");
|
||||
|
||||
values.count++;
|
||||
}
|
||||
|
||||
joined = strv_join(arg_banks, ", ");
|
||||
if (!joined)
|
||||
return log_oom();
|
||||
|
||||
log_debug("Measuring '%s' into PCR index %u, banks %s.", word, TPM_PCR_INDEX_KERNEL_IMAGE, joined);
|
||||
|
||||
rc = sym_Esys_PCR_Extend(
|
||||
c.esys_context,
|
||||
ESYS_TR_PCR0 + TPM_PCR_INDEX_KERNEL_IMAGE, /* → PCR 11 */
|
||||
ESYS_TR_PASSWORD,
|
||||
ESYS_TR_NONE,
|
||||
ESYS_TR_NONE,
|
||||
&values);
|
||||
if (rc != TSS2_RC_SUCCESS)
|
||||
return log_error_errno(
|
||||
SYNTHETIC_ERRNO(ENOTRECOVERABLE),
|
||||
"Failed to measure '%s': %s",
|
||||
word,
|
||||
sym_Tss2_RC_Decode(rc));
|
||||
|
||||
log_struct(LOG_INFO,
|
||||
"MESSAGE_ID=" SD_MESSAGE_TPM_PCR_EXTEND_STR,
|
||||
LOG_MESSAGE("Successfully extended PCR index %u with '%s' (banks %s).", TPM_PCR_INDEX_KERNEL_IMAGE, word, joined),
|
||||
"MEASURING=%s", word,
|
||||
"PCR=%u", TPM_PCR_INDEX_KERNEL_IMAGE,
|
||||
"BANKS=%s", joined);
|
||||
|
||||
return EXIT_SUCCESS;
|
||||
}
|
||||
|
||||
DEFINE_MAIN_FUNCTION(run);
|
||||
@@ -189,6 +189,9 @@ _SD_BEGIN_DECLARATIONS;
|
||||
#define SD_MESSAGE_SHUTDOWN_CANCELED SD_ID128_MAKE(24,9f,6f,b9,e6,e2,42,8c,96,f3,f0,87,56,81,ff,a3)
|
||||
#define SD_MESSAGE_SHUTDOWN_CANCELED_STR SD_ID128_MAKE_STR(24,9f,6f,b9,e6,e2,42,8c,96,f3,f0,87,56,81,ff,a3)
|
||||
|
||||
#define SD_MESSAGE_TPM_PCR_EXTEND SD_ID128_MAKE(3f,7d,5e,f3,e5,4f,43,02,b4,f0,b1,43,bb,27,0c,ab)
|
||||
#define SD_MESSAGE_TPM_PCR_EXTEND_STR SD_ID128_MAKE_STR(3f,7d,5e,f3,e5,4f,43,02,b4,f0,b1,43,bb,27,0c,ab)
|
||||
|
||||
_SD_END_DECLARATIONS;
|
||||
|
||||
#endif
|
||||
|
||||
Reference in New Issue
Block a user