373 lines
16 KiB
Diff
373 lines
16 KiB
Diff
From d2b974f55d80f09d544a3af6a2ef987df4284260 Mon Sep 17 00:00:00 2001
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From: Lennart Poettering <lennart@poettering.net>
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Date: Fri, 14 Oct 2022 23:29:48 +0200
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Subject: [PATCH] pcrphase: make tool more generic, reuse for measuring machine
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id/fs uuids
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See: #24503
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(cherry picked from commit 17984c55513fc18f9bd4878c37fa87d278ab1e1d)
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Related: RHEL-16182
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---
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meson.build | 4 +-
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src/boot/pcrphase.c | 210 +++++++++++++++++++++++++++++++++++++++-----
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2 files changed, 189 insertions(+), 25 deletions(-)
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diff --git a/meson.build b/meson.build
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index fe7b47eef5..54155eee1f 100644
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--- a/meson.build
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+++ b/meson.build
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@@ -2610,7 +2610,9 @@ if conf.get('HAVE_BLKID') == 1 and conf.get('HAVE_GNU_EFI') == 1
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'src/boot/pcrphase.c',
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include_directories : includes,
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link_with : [libshared],
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- dependencies : [libopenssl, tpm2],
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+ dependencies : [libopenssl,
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+ tpm2,
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+ libblkid],
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install_rpath : rootpkglibdir,
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install : true,
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install_dir : rootlibexecdir)
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diff --git a/src/boot/pcrphase.c b/src/boot/pcrphase.c
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index 1f3dc4ab3a..12629b2be3 100644
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--- a/src/boot/pcrphase.c
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+++ b/src/boot/pcrphase.c
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@@ -2,12 +2,20 @@
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#include <getopt.h>
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+#include <sd-device.h>
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#include <sd-messages.h>
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+#include "blkid-util.h"
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+#include "blockdev-util.h"
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+#include "chase-symlinks.h"
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#include "efivars.h"
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#include "env-util.h"
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+#include "escape.h"
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+#include "fd-util.h"
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#include "main-func.h"
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+#include "mountpoint-util.h"
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#include "openssl-util.h"
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+#include "parse-argument.h"
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#include "parse-util.h"
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#include "pretty-print.h"
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#include "tpm-pcr.h"
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@@ -16,9 +24,12 @@
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static bool arg_graceful = false;
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static char *arg_tpm2_device = NULL;
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static char **arg_banks = NULL;
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+static char *arg_file_system = NULL;
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+static bool arg_machine_id = false;
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STATIC_DESTRUCTOR_REGISTER(arg_banks, strv_freep);
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STATIC_DESTRUCTOR_REGISTER(arg_tpm2_device, freep);
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+STATIC_DESTRUCTOR_REGISTER(arg_file_system, freep);
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static int help(int argc, char *argv[], void *userdata) {
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_cleanup_free_ char *link = NULL;
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@@ -28,7 +39,9 @@ static int help(int argc, char *argv[], void *userdata) {
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if (r < 0)
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return log_oom();
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- printf("%1$s [OPTIONS...] WORD ...\n"
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+ printf("%1$s [OPTIONS...] WORD\n"
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+ "%1$s [OPTIONS...] --file-system=PATH\n"
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+ "%1$s [OPTIONS...] --machine-id\n"
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"\n%5$sMeasure boot phase into TPM2 PCR 11.%6$s\n"
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"\n%3$sOptions:%4$s\n"
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" -h --help Show this help\n"
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@@ -36,6 +49,8 @@ static int help(int argc, char *argv[], void *userdata) {
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" --bank=DIGEST Select TPM bank (SHA1, SHA256)\n"
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" --tpm2-device=PATH Use specified TPM2 device\n"
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" --graceful Exit gracefully if no TPM2 device is found\n"
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+ " --file-system=PATH Measure UUID/labels of file system into PCR 15\n"
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+ " --machine-id Measure machine ID into PCR 15\n"
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"\nSee the %2$s for details.\n",
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program_invocation_short_name,
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link,
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@@ -53,6 +68,8 @@ static int parse_argv(int argc, char *argv[]) {
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ARG_BANK,
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ARG_TPM2_DEVICE,
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ARG_GRACEFUL,
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+ ARG_FILE_SYSTEM,
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+ ARG_MACHINE_ID,
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};
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static const struct option options[] = {
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@@ -61,10 +78,12 @@ static int parse_argv(int argc, char *argv[]) {
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{ "bank", required_argument, NULL, ARG_BANK },
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{ "tpm2-device", required_argument, NULL, ARG_TPM2_DEVICE },
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{ "graceful", no_argument, NULL, ARG_GRACEFUL },
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+ { "file-system", required_argument, NULL, ARG_FILE_SYSTEM },
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+ { "machine-id", no_argument, NULL, ARG_MACHINE_ID },
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{}
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};
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- int c;
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+ int c, r;
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assert(argc >= 0);
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assert(argv);
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@@ -112,6 +131,17 @@ static int parse_argv(int argc, char *argv[]) {
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arg_graceful = true;
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break;
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+ case ARG_FILE_SYSTEM:
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+ r = parse_path_argument(optarg, /* suppress_root= */ false, &arg_file_system);
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+ if (r < 0)
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+ return r;
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+
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+ break;
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+
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+ case ARG_MACHINE_ID:
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+ arg_machine_id = true;
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+ break;
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+
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case '?':
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return -EINVAL;
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@@ -119,10 +149,13 @@ static int parse_argv(int argc, char *argv[]) {
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assert_not_reached();
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}
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+ if (arg_file_system && arg_machine_id)
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+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "--file-system= and --machine-id may not be combined.");
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+
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return 1;
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}
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-static int determine_banks(struct tpm2_context *c) {
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+static int determine_banks(struct tpm2_context *c, unsigned target_pcr_nr) {
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_cleanup_strv_free_ char **l = NULL;
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int r;
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@@ -131,7 +164,7 @@ static int determine_banks(struct tpm2_context *c) {
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if (!strv_isempty(arg_banks)) /* Explicitly configured? Then use that */
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return 0;
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- r = tpm2_get_good_pcr_banks_strv(c->esys_context, UINT32_C(1) << TPM_PCR_INDEX_KERNEL_IMAGE, &l);
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+ r = tpm2_get_good_pcr_banks_strv(c->esys_context, UINT32_C(1) << target_pcr_nr, &l);
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if (r < 0)
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return r;
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@@ -139,11 +172,77 @@ static int determine_banks(struct tpm2_context *c) {
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return 0;
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}
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+static int get_file_system_word(
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+ sd_device *d,
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+ const char *prefix,
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+ char **ret) {
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+
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+ int r;
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+
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+ assert(d);
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+ assert(prefix);
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+ assert(ret);
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+
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+ _cleanup_close_ int block_fd = sd_device_open(d, O_RDONLY|O_CLOEXEC|O_NONBLOCK);
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+ if (block_fd < 0)
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+ return block_fd;
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+
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+ _cleanup_(blkid_free_probep) blkid_probe b = blkid_new_probe();
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+ if (!b)
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+ return -ENOMEM;
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+
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+ errno = 0;
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+ r = blkid_probe_set_device(b, block_fd, 0, 0);
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+ if (r != 0)
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+ return errno_or_else(ENOMEM);
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+
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+ (void) blkid_probe_enable_superblocks(b, 1);
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+ (void) blkid_probe_set_superblocks_flags(b, BLKID_SUBLKS_TYPE|BLKID_SUBLKS_UUID|BLKID_SUBLKS_LABEL);
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+ (void) blkid_probe_enable_partitions(b, 1);
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+ (void) blkid_probe_set_partitions_flags(b, BLKID_PARTS_ENTRY_DETAILS);
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+
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+ errno = 0;
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+ r = blkid_do_safeprobe(b);
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+ if (r == _BLKID_SAFEPROBE_ERROR)
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+ return errno_or_else(EIO);
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+ if (IN_SET(r, _BLKID_SAFEPROBE_AMBIGUOUS, _BLKID_SAFEPROBE_NOT_FOUND))
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+ return -ENOPKG;
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+
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+ assert(r == _BLKID_SAFEPROBE_FOUND);
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+
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+ _cleanup_strv_free_ char **l = strv_new(prefix);
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+ if (!l)
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+ return log_oom();
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+
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+ FOREACH_STRING(field, "TYPE", "UUID", "LABEL", "PART_ENTRY_UUID", "PART_ENTRY_TYPE", "PART_ENTRY_NAME") {
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+ const char *v = NULL;
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+
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+ (void) blkid_probe_lookup_value(b, field, &v, NULL);
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+
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+ _cleanup_free_ char *escaped = xescape(strempty(v), ":"); /* Avoid ambiguity around ":" */
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+ if (!escaped)
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+ return log_oom();
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+
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+ r = strv_consume(&l, TAKE_PTR(escaped));
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+ if (r < 0)
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+ return log_oom();
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+
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+ }
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+
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+ assert(strv_length(l) == 7); /* We always want 7 components, to avoid ambiguous strings */
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+
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+ _cleanup_free_ char *word = strv_join(l, ":");
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+ if (!word)
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+ return log_oom();
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+
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+ *ret = TAKE_PTR(word);
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+ return 0;
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+}
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+
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static int run(int argc, char *argv[]) {
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+ _cleanup_free_ char *joined = NULL, *pcr_string = NULL, *word = NULL;
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_cleanup_(tpm2_context_destroy) struct tpm2_context c = {};
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- _cleanup_free_ char *joined = NULL, *pcr_string = NULL;
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- const char *word;
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- unsigned pcr_nr;
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+ unsigned target_pcr_nr, efi_pcr_nr;
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size_t length;
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int r;
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@@ -153,16 +252,79 @@ static int run(int argc, char *argv[]) {
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if (r <= 0)
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return r;
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- if (optind+1 != argc)
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- return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Expected a single argument.");
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+ if (arg_file_system) {
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+ _cleanup_free_ char *normalized = NULL, *normalized_escaped = NULL;
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+ _cleanup_(sd_device_unrefp) sd_device *d = NULL;
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+ _cleanup_close_ int dfd = -EBADF;
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+
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+ if (optind != argc)
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+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Expected no argument.");
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- word = argv[optind];
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+ dfd = chase_symlinks_and_open(arg_file_system, NULL, 0, O_DIRECTORY|O_CLOEXEC, &normalized);
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+ if (dfd < 0)
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+ return log_error_errno(dfd, "Failed to open path '%s': %m", arg_file_system);
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- /* Refuse to measure an empty word. We want to be able to write the series of measured words
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- * separated by colons, where multiple separating colons are collapsed. Thus it makes sense to
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- * disallow an empty word to avoid ambiguities. */
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- if (isempty(word))
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- return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "String to measure cannot be empty, refusing.");
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+ r = fd_is_mount_point(dfd, NULL, 0);
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+ if (r < 0)
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+ return log_error_errno(r, "Failed to determine if path '%s' is mount point: %m", normalized);
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+ if (r == 0)
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+ return log_error_errno(SYNTHETIC_ERRNO(ENOTDIR), "Specified path '%s' is not a mount point, refusing: %m", normalized);
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+
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+ normalized_escaped = xescape(normalized, ":"); /* Avoid ambiguity around ":" */
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+ if (!normalized_escaped)
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+ return log_oom();
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+
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+ _cleanup_free_ char* prefix = strjoin("file-system:", normalized_escaped);
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+ if (!prefix)
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+ return log_oom();
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+
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+ r = block_device_new_from_fd(dfd, BLOCK_DEVICE_LOOKUP_BACKING, &d);
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+ if (r < 0) {
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+ log_notice_errno(r, "Unable to determine backing block device of '%s', measuring generic fallback file system identity string: %m", arg_file_system);
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+
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+ word = strjoin(prefix, "::::::");
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+ if (!word)
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+ return log_oom();
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+ } else {
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+ r = get_file_system_word(d, prefix, &word);
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+ if (r < 0)
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+ return log_error_errno(r, "Failed to get file system identifier string for '%s': %m", arg_file_system);
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+ }
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+
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+ target_pcr_nr = TPM_PCR_INDEX_VOLUME_KEY; /* → PCR 15 */
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+
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+ } else if (arg_machine_id) {
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+ sd_id128_t mid;
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+
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+ if (optind != argc)
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+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Expected no argument.");
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+
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+ r = sd_id128_get_machine(&mid);
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+ if (r < 0)
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+ return log_error_errno(r, "Failed to acquire machine ID: %m");
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+
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+ word = strjoin("machine-id:", SD_ID128_TO_STRING(mid));
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+ if (!word)
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+ return log_oom();
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+
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+ target_pcr_nr = TPM_PCR_INDEX_VOLUME_KEY; /* → PCR 15 */
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+
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+ } else {
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+ if (optind+1 != argc)
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+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Expected a single argument.");
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+
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+ word = strdup(argv[optind]);
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+ if (!word)
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+ return log_oom();
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+
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+ /* Refuse to measure an empty word. We want to be able to write the series of measured words
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+ * separated by colons, where multiple separating colons are collapsed. Thus it makes sense to
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+ * disallow an empty word to avoid ambiguities. */
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+ if (isempty(word))
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+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "String to measure cannot be empty, refusing.");
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+
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+ target_pcr_nr = TPM_PCR_INDEX_KERNEL_IMAGE; /* → PCR 11 */
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+ }
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if (arg_graceful && tpm2_support() != TPM2_SUPPORT_FULL) {
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log_notice("No complete TPM2 support detected, exiting gracefully.");
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@@ -187,14 +349,14 @@ static int run(int argc, char *argv[]) {
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return log_error_errno(r, "Failed to read StubPcrKernelImage EFI variable: %m");
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else {
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/* Let's validate that the stub announced PCR 11 as we expected. */
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- r = safe_atou(pcr_string, &pcr_nr);
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+ r = safe_atou(pcr_string, &efi_pcr_nr);
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if (r < 0)
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return log_error_errno(r, "Failed to parse StubPcrKernelImage EFI variable: %s", pcr_string);
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- if (pcr_nr != TPM_PCR_INDEX_KERNEL_IMAGE) {
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+ if (efi_pcr_nr != TPM_PCR_INDEX_KERNEL_IMAGE) {
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if (b != 0)
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- 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);
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+ 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);
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else
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- 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);
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+ 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);
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} else
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log_debug("Kernel stub reported same PCR %u as we want to use, proceeding.", TPM_PCR_INDEX_KERNEL_IMAGE);
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}
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@@ -207,7 +369,7 @@ static int run(int argc, char *argv[]) {
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if (r < 0)
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return r;
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- r = determine_banks(&c);
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+ r = determine_banks(&c, target_pcr_nr);
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if (r < 0)
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return r;
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if (strv_isempty(arg_banks)) /* Still none? */
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@@ -217,17 +379,17 @@ static int run(int argc, char *argv[]) {
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if (!joined)
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return log_oom();
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- log_debug("Measuring '%s' into PCR index %u, banks %s.", word, TPM_PCR_INDEX_KERNEL_IMAGE, joined);
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+ log_debug("Measuring '%s' into PCR index %u, banks %s.", word, target_pcr_nr, joined);
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- r = tpm2_extend_bytes(c.esys_context, arg_banks, TPM_PCR_INDEX_KERNEL_IMAGE, word, length, NULL, 0); /* → PCR 11 */
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+ r = tpm2_extend_bytes(c.esys_context, arg_banks, target_pcr_nr, word, length, NULL, 0);
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if (r < 0)
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return r;
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log_struct(LOG_INFO,
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"MESSAGE_ID=" SD_MESSAGE_TPM_PCR_EXTEND_STR,
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- LOG_MESSAGE("Successfully extended PCR index %u with '%s' (banks %s).", TPM_PCR_INDEX_KERNEL_IMAGE, word, joined),
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+ LOG_MESSAGE("Extended PCR index %u with '%s' (banks %s).", target_pcr_nr, word, joined),
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"MEASURING=%s", word,
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- "PCR=%u", TPM_PCR_INDEX_KERNEL_IMAGE,
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+ "PCR=%u", target_pcr_nr,
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"BANKS=%s", joined);
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return EXIT_SUCCESS;
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