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systemd/SOURCES/0486-pcrphase-make-tool-mor...

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import systemd-252-32.el9_4
6 months ago
From d2b974f55d80f09d544a3af6a2ef987df4284260 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 14 Oct 2022 23:29:48 +0200
Subject: [PATCH] pcrphase: make tool more generic, reuse for measuring machine
id/fs uuids
See: #24503
(cherry picked from commit 17984c55513fc18f9bd4878c37fa87d278ab1e1d)
Related: RHEL-16182
---
meson.build | 4 +-
src/boot/pcrphase.c | 210 +++++++++++++++++++++++++++++++++++++++-----
2 files changed, 189 insertions(+), 25 deletions(-)
diff --git a/meson.build b/meson.build
index fe7b47eef5..54155eee1f 100644
--- a/meson.build
+++ b/meson.build
@@ -2610,7 +2610,9 @@ if conf.get('HAVE_BLKID') == 1 and conf.get('HAVE_GNU_EFI') == 1
'src/boot/pcrphase.c',
include_directories : includes,
link_with : [libshared],
- dependencies : [libopenssl, tpm2],
+ dependencies : [libopenssl,
+ tpm2,
+ libblkid],
install_rpath : rootpkglibdir,
install : true,
install_dir : rootlibexecdir)
diff --git a/src/boot/pcrphase.c b/src/boot/pcrphase.c
index 1f3dc4ab3a..12629b2be3 100644
--- a/src/boot/pcrphase.c
+++ b/src/boot/pcrphase.c
@@ -2,12 +2,20 @@
#include <getopt.h>
+#include <sd-device.h>
#include <sd-messages.h>
+#include "blkid-util.h"
+#include "blockdev-util.h"
+#include "chase-symlinks.h"
#include "efivars.h"
#include "env-util.h"
+#include "escape.h"
+#include "fd-util.h"
#include "main-func.h"
+#include "mountpoint-util.h"
#include "openssl-util.h"
+#include "parse-argument.h"
#include "parse-util.h"
#include "pretty-print.h"
#include "tpm-pcr.h"
@@ -16,9 +24,12 @@
static bool arg_graceful = false;
static char *arg_tpm2_device = NULL;
static char **arg_banks = NULL;
+static char *arg_file_system = NULL;
+static bool arg_machine_id = false;
STATIC_DESTRUCTOR_REGISTER(arg_banks, strv_freep);
STATIC_DESTRUCTOR_REGISTER(arg_tpm2_device, freep);
+STATIC_DESTRUCTOR_REGISTER(arg_file_system, freep);
static int help(int argc, char *argv[], void *userdata) {
_cleanup_free_ char *link = NULL;
@@ -28,7 +39,9 @@ static int help(int argc, char *argv[], void *userdata) {
if (r < 0)
return log_oom();
- printf("%1$s [OPTIONS...] WORD ...\n"
+ printf("%1$s [OPTIONS...] WORD\n"
+ "%1$s [OPTIONS...] --file-system=PATH\n"
+ "%1$s [OPTIONS...] --machine-id\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"
@@ -36,6 +49,8 @@ static int help(int argc, char *argv[], void *userdata) {
" --bank=DIGEST Select TPM bank (SHA1, SHA256)\n"
" --tpm2-device=PATH Use specified TPM2 device\n"
" --graceful Exit gracefully if no TPM2 device is found\n"
+ " --file-system=PATH Measure UUID/labels of file system into PCR 15\n"
+ " --machine-id Measure machine ID into PCR 15\n"
"\nSee the %2$s for details.\n",
program_invocation_short_name,
link,
@@ -53,6 +68,8 @@ static int parse_argv(int argc, char *argv[]) {
ARG_BANK,
ARG_TPM2_DEVICE,
ARG_GRACEFUL,
+ ARG_FILE_SYSTEM,
+ ARG_MACHINE_ID,
};
static const struct option options[] = {
@@ -61,10 +78,12 @@ static int parse_argv(int argc, char *argv[]) {
{ "bank", required_argument, NULL, ARG_BANK },
{ "tpm2-device", required_argument, NULL, ARG_TPM2_DEVICE },
{ "graceful", no_argument, NULL, ARG_GRACEFUL },
+ { "file-system", required_argument, NULL, ARG_FILE_SYSTEM },
+ { "machine-id", no_argument, NULL, ARG_MACHINE_ID },
{}
};
- int c;
+ int c, r;
assert(argc >= 0);
assert(argv);
@@ -112,6 +131,17 @@ static int parse_argv(int argc, char *argv[]) {
arg_graceful = true;
break;
+ case ARG_FILE_SYSTEM:
+ r = parse_path_argument(optarg, /* suppress_root= */ false, &arg_file_system);
+ if (r < 0)
+ return r;
+
+ break;
+
+ case ARG_MACHINE_ID:
+ arg_machine_id = true;
+ break;
+
case '?':
return -EINVAL;
@@ -119,10 +149,13 @@ static int parse_argv(int argc, char *argv[]) {
assert_not_reached();
}
+ if (arg_file_system && arg_machine_id)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "--file-system= and --machine-id may not be combined.");
+
return 1;
}
-static int determine_banks(struct tpm2_context *c) {
+static int determine_banks(struct tpm2_context *c, unsigned target_pcr_nr) {
_cleanup_strv_free_ char **l = NULL;
int r;
@@ -131,7 +164,7 @@ static int determine_banks(struct tpm2_context *c) {
if (!strv_isempty(arg_banks)) /* Explicitly configured? Then use that */
return 0;
- r = tpm2_get_good_pcr_banks_strv(c->esys_context, UINT32_C(1) << TPM_PCR_INDEX_KERNEL_IMAGE, &l);
+ r = tpm2_get_good_pcr_banks_strv(c->esys_context, UINT32_C(1) << target_pcr_nr, &l);
if (r < 0)
return r;
@@ -139,11 +172,77 @@ static int determine_banks(struct tpm2_context *c) {
return 0;
}
+static int get_file_system_word(
+ sd_device *d,
+ const char *prefix,
+ char **ret) {
+
+ int r;
+
+ assert(d);
+ assert(prefix);
+ assert(ret);
+
+ _cleanup_close_ int block_fd = sd_device_open(d, O_RDONLY|O_CLOEXEC|O_NONBLOCK);
+ if (block_fd < 0)
+ return block_fd;
+
+ _cleanup_(blkid_free_probep) blkid_probe b = blkid_new_probe();
+ if (!b)
+ return -ENOMEM;
+
+ errno = 0;
+ r = blkid_probe_set_device(b, block_fd, 0, 0);
+ if (r != 0)
+ return errno_or_else(ENOMEM);
+
+ (void) blkid_probe_enable_superblocks(b, 1);
+ (void) blkid_probe_set_superblocks_flags(b, BLKID_SUBLKS_TYPE|BLKID_SUBLKS_UUID|BLKID_SUBLKS_LABEL);
+ (void) blkid_probe_enable_partitions(b, 1);
+ (void) blkid_probe_set_partitions_flags(b, BLKID_PARTS_ENTRY_DETAILS);
+
+ errno = 0;
+ r = blkid_do_safeprobe(b);
+ if (r == _BLKID_SAFEPROBE_ERROR)
+ return errno_or_else(EIO);
+ if (IN_SET(r, _BLKID_SAFEPROBE_AMBIGUOUS, _BLKID_SAFEPROBE_NOT_FOUND))
+ return -ENOPKG;
+
+ assert(r == _BLKID_SAFEPROBE_FOUND);
+
+ _cleanup_strv_free_ char **l = strv_new(prefix);
+ if (!l)
+ return log_oom();
+
+ FOREACH_STRING(field, "TYPE", "UUID", "LABEL", "PART_ENTRY_UUID", "PART_ENTRY_TYPE", "PART_ENTRY_NAME") {
+ const char *v = NULL;
+
+ (void) blkid_probe_lookup_value(b, field, &v, NULL);
+
+ _cleanup_free_ char *escaped = xescape(strempty(v), ":"); /* Avoid ambiguity around ":" */
+ if (!escaped)
+ return log_oom();
+
+ r = strv_consume(&l, TAKE_PTR(escaped));
+ if (r < 0)
+ return log_oom();
+
+ }
+
+ assert(strv_length(l) == 7); /* We always want 7 components, to avoid ambiguous strings */
+
+ _cleanup_free_ char *word = strv_join(l, ":");
+ if (!word)
+ return log_oom();
+
+ *ret = TAKE_PTR(word);
+ return 0;
+}
+
static int run(int argc, char *argv[]) {
+ _cleanup_free_ char *joined = NULL, *pcr_string = NULL, *word = NULL;
_cleanup_(tpm2_context_destroy) struct tpm2_context c = {};
- _cleanup_free_ char *joined = NULL, *pcr_string = NULL;
- const char *word;
- unsigned pcr_nr;
+ unsigned target_pcr_nr, efi_pcr_nr;
size_t length;
int r;
@@ -153,16 +252,79 @@ static int run(int argc, char *argv[]) {
if (r <= 0)
return r;
- if (optind+1 != argc)
- return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Expected a single argument.");
+ if (arg_file_system) {
+ _cleanup_free_ char *normalized = NULL, *normalized_escaped = NULL;
+ _cleanup_(sd_device_unrefp) sd_device *d = NULL;
+ _cleanup_close_ int dfd = -EBADF;
+
+ if (optind != argc)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Expected no argument.");
- word = argv[optind];
+ dfd = chase_symlinks_and_open(arg_file_system, NULL, 0, O_DIRECTORY|O_CLOEXEC, &normalized);
+ if (dfd < 0)
+ return log_error_errno(dfd, "Failed to open path '%s': %m", arg_file_system);
- /* 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.");
+ r = fd_is_mount_point(dfd, NULL, 0);
+ if (r < 0)
+ return log_error_errno(r, "Failed to determine if path '%s' is mount point: %m", normalized);
+ if (r == 0)
+ return log_error_errno(SYNTHETIC_ERRNO(ENOTDIR), "Specified path '%s' is not a mount point, refusing: %m", normalized);
+
+ normalized_escaped = xescape(normalized, ":"); /* Avoid ambiguity around ":" */
+ if (!normalized_escaped)
+ return log_oom();
+
+ _cleanup_free_ char* prefix = strjoin("file-system:", normalized_escaped);
+ if (!prefix)
+ return log_oom();
+
+ r = block_device_new_from_fd(dfd, BLOCK_DEVICE_LOOKUP_BACKING, &d);
+ if (r < 0) {
+ log_notice_errno(r, "Unable to determine backing block device of '%s', measuring generic fallback file system identity string: %m", arg_file_system);
+
+ word = strjoin(prefix, "::::::");
+ if (!word)
+ return log_oom();
+ } else {
+ r = get_file_system_word(d, prefix, &word);
+ if (r < 0)
+ return log_error_errno(r, "Failed to get file system identifier string for '%s': %m", arg_file_system);
+ }
+
+ target_pcr_nr = TPM_PCR_INDEX_VOLUME_KEY; /* → PCR 15 */
+
+ } else if (arg_machine_id) {
+ sd_id128_t mid;
+
+ if (optind != argc)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Expected no argument.");
+
+ r = sd_id128_get_machine(&mid);
+ if (r < 0)
+ return log_error_errno(r, "Failed to acquire machine ID: %m");
+
+ word = strjoin("machine-id:", SD_ID128_TO_STRING(mid));
+ if (!word)
+ return log_oom();
+
+ target_pcr_nr = TPM_PCR_INDEX_VOLUME_KEY; /* → PCR 15 */
+
+ } else {
+ if (optind+1 != argc)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Expected a single argument.");
+
+ word = strdup(argv[optind]);
+ if (!word)
+ return log_oom();
+
+ /* 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.");
+
+ target_pcr_nr = TPM_PCR_INDEX_KERNEL_IMAGE; /* → PCR 11 */
+ }
if (arg_graceful && tpm2_support() != TPM2_SUPPORT_FULL) {
log_notice("No complete TPM2 support detected, exiting gracefully.");
@@ -187,14 +349,14 @@ static int run(int argc, char *argv[]) {
return log_error_errno(r, "Failed to read StubPcrKernelImage EFI variable: %m");
else {
/* Let's validate that the stub announced PCR 11 as we expected. */
- r = safe_atou(pcr_string, &pcr_nr);
+ r = safe_atou(pcr_string, &efi_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) {
+ if (efi_pcr_nr != TPM_PCR_INDEX_KERNEL_IMAGE) {
if (b != 0)
- 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);
+ return log_error_errno(SYNTHETIC_ERRNO(EREMOTE), "Kernel stub measured kernel image into PCR %u, which is different than expected %u.", efi_pcr_nr, TPM_PCR_INDEX_KERNEL_IMAGE);
else
- log_notice("Kernel stub measured kernel image into PCR %u, which is different than expected %u, but told to measure anyway, hence proceeding.", pcr_nr, TPM_PCR_INDEX_KERNEL_IMAGE);
+ log_notice("Kernel stub measured kernel image into PCR %u, which is different than expected %u, but told to measure anyway, hence proceeding.", efi_pcr_nr, TPM_PCR_INDEX_KERNEL_IMAGE);
} else
log_debug("Kernel stub reported same PCR %u as we want to use, proceeding.", TPM_PCR_INDEX_KERNEL_IMAGE);
}
@@ -207,7 +369,7 @@ static int run(int argc, char *argv[]) {
if (r < 0)
return r;
- r = determine_banks(&c);
+ r = determine_banks(&c, target_pcr_nr);
if (r < 0)
return r;
if (strv_isempty(arg_banks)) /* Still none? */
@@ -217,17 +379,17 @@ static int run(int argc, char *argv[]) {
if (!joined)
return log_oom();
- log_debug("Measuring '%s' into PCR index %u, banks %s.", word, TPM_PCR_INDEX_KERNEL_IMAGE, joined);
+ log_debug("Measuring '%s' into PCR index %u, banks %s.", word, target_pcr_nr, joined);
- r = tpm2_extend_bytes(c.esys_context, arg_banks, TPM_PCR_INDEX_KERNEL_IMAGE, word, length, NULL, 0); /* → PCR 11 */
+ r = tpm2_extend_bytes(c.esys_context, arg_banks, target_pcr_nr, word, length, NULL, 0);
if (r < 0)
return r;
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),
+ LOG_MESSAGE("Extended PCR index %u with '%s' (banks %s).", target_pcr_nr, word, joined),
"MEASURING=%s", word,
- "PCR=%u", TPM_PCR_INDEX_KERNEL_IMAGE,
+ "PCR=%u", target_pcr_nr,
"BANKS=%s", joined);
return EXIT_SUCCESS;