older systemd versions, however systemd continues to accept TPM-sealed
credentials that were created before this change.
+ * The "tpm2-measure-bank=" crypttab option of systemd-cryptsetup is
+ now deprecated and has no effect. Volume key measurements are
+ performed via varlink call to systemd-pcrextend, which automatically
+ selects all suitable TPM2 PCR banks; the banks can no longer be
+ restricted per volume.
+
* The legacy socket for controlling systemd-udevd has been removed, and
udevadm now unconditionally uses Varlink IPC. The legacy UNIX socket
/run/udev/control, which is sometimes used to check whether udevd is
<varlistentry>
<term><option>tpm2-measure-bank=</option></term>
- <listitem><para>Selects one or more TPM2 PCR banks to measure the volume key into, as configured with
- <option>tpm2-measure-pcr=</option> above. Multiple banks may be specified, separated by a colon
- character. If not specified, automatically determines available and used banks. Expects a message
- digest name (e.g. <literal>sha1</literal>, <literal>sha256</literal>, …) as argument, to identify the
- bank.</para>
+ <listitem><para>This option is deprecated and has no effect since version 262. All suitable PCR
+ banks are used.</para>
<xi:include href="version-info.xml" xpointer="v253"/></listitem>
</varlistentry>
#include "sd-device.h"
#include "sd-event.h"
#include "sd-json.h"
-#include "sd-messages.h"
#include "alloc-util.h"
#include "ask-password-api.h"
#include "build.h"
-#include "crypto-util.h"
#include "cryptsetup-fido2.h"
#include "cryptsetup-keyfile.h"
#include "cryptsetup-pkcs11.h"
#include "options.h"
#include "parse-util.h"
#include "path-util.h"
+#include "pcrextend-util.h"
#include "pkcs11-util.h"
#include "pretty-print.h"
#include "process-util.h"
static char *arg_tpm2_pcrlock = NULL;
static usec_t arg_token_timeout_usec = 30*USEC_PER_SEC;
static unsigned arg_tpm2_measure_pcr = UINT_MAX; /* This and the following field is about measuring the unlocked volume key to the local TPM */
-static char **arg_tpm2_measure_banks = NULL;
static char *arg_tpm2_measure_keyslot_nvpcr = NULL;
static char *arg_link_keyring = NULL;
static char *arg_link_key_type = NULL;
STATIC_DESTRUCTOR_REGISTER(arg_fido2_rp_id, freep);
STATIC_DESTRUCTOR_REGISTER(arg_tpm2_device, freep);
STATIC_DESTRUCTOR_REGISTER(arg_tpm2_signature, freep);
-STATIC_DESTRUCTOR_REGISTER(arg_tpm2_measure_banks, strv_freep);
STATIC_DESTRUCTOR_REGISTER(arg_tpm2_measure_keyslot_nvpcr, freep);
STATIC_DESTRUCTOR_REGISTER(arg_tpm2_pcrlock, freep);
STATIC_DESTRUCTOR_REGISTER(arg_link_keyring, freep);
} else if ((val = startswith(option, "tpm2-measure-bank="))) {
-#if HAVE_OPENSSL
- _cleanup_strv_free_ char **l = NULL;
-
- r = dlopen_libcrypto(LOG_ERR);
- if (r < 0)
- return r;
-
- l = strv_split(val, ":");
- if (!l)
- return log_oom();
-
- STRV_FOREACH(i, l) {
- const EVP_MD *implementation;
-
- implementation = sym_EVP_get_digestbyname(*i);
- if (!implementation)
- return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Unknown bank '%s', refusing.", val);
-
- if (strv_extend(&arg_tpm2_measure_banks, sym_EVP_MD_get0_name(implementation)) < 0)
- return log_oom();
- }
-#else
- log_error("Build lacks OpenSSL support, cannot measure to PCR banks, ignoring: %s", option);
-#endif
+ /* Deprecated: the PCR banks to measure into are now chosen by systemd-pcrextend
+ * (it extends all suitable banks). Kept for compatibility, but ignored. */
+ log_warning("The tpm2-measure-bank= option is deprecated and has no effect, ignoring.");
} else if ((val = startswith(option, "tpm2-measure-keyslot-nvpcr="))) {
return 0;
}
-#if HAVE_TPM2
- _cleanup_(tpm2_context_unrefp) Tpm2Context *c = NULL;
- r = tpm2_context_new_or_warn(arg_tpm2_device, &c);
- if (r < 0)
- return r;
-
- _cleanup_strv_free_ char **l = NULL;
- if (strv_isempty(arg_tpm2_measure_banks)) {
- r = tpm2_get_good_pcr_banks_strv(c, UINT32_C(1) << arg_tpm2_measure_pcr, &l);
- if (r < 0)
- return log_error_errno(r, "Could not verify pcr banks: %m");
- }
-
- _cleanup_free_ char *joined = strv_join(l ?: arg_tpm2_measure_banks, ", ");
- if (!joined)
- return log_oom();
-
- /* Note: we don't directly measure the volume key, it might be a security problem to send an
- * unprotected direct hash of the secret volume key over the wire to the TPM. Hence let's instead
- * send a HMAC signature instead. */
-
_cleanup_free_ char *prefix = NULL;
/* Note: what is extended to the SHA256 bank here must match the expected hash of 'fixate-volume-key='
* calculated by cryptsetup_get_volume_key_id(). */
r = cryptsetup_get_volume_key_prefix(cd, name, &prefix);
- if (r)
- return log_error_errno(r, "Could not verify pcr banks: %m");
-
- r = tpm2_pcr_extend_bytes(
- c,
- /* banks= */ l ?: arg_tpm2_measure_banks,
- /* pcr_index = */ arg_tpm2_measure_pcr,
- /* data = */ &IOVEC_MAKE_STRING(prefix),
- /* secret = */ &IOVEC_MAKE(volume_key, volume_key_size),
- /* event_type = */ TPM2_EVENT_VOLUME_KEY,
- /* description = */ prefix);
if (r < 0)
- return log_error_errno(r, "Could not extend PCR: %m");
+ return log_error_errno(r, "Failed to get volume key prefix: %m");
- log_struct(LOG_INFO,
- LOG_MESSAGE_ID(SD_MESSAGE_TPM_PCR_EXTEND_STR),
- LOG_MESSAGE("Successfully extended PCR index %u with '%s' and volume key (banks %s).", arg_tpm2_measure_pcr, prefix, joined),
- LOG_ITEM("MEASURING=%s", prefix),
- LOG_ITEM("PCR=%u", arg_tpm2_measure_pcr),
- LOG_ITEM("BANKS=%s", joined));
+ /* Pass the volume key as HMAC secret. pcrextend extends HMAC(volume_key, prefix),
+ * never a bare hash. Matches cryptsetup_get_volume_key_id(). */
+ r = pcrextend_pcr_now(arg_tpm2_measure_pcr, prefix, &IOVEC_MAKE(volume_key, volume_key_size), "volume_key");
+ if (r < 0)
+ return log_error_errno(r, "Could not extend PCR: %m");
return 0;
-#else
- return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "TPM2 support disabled, not measuring volume key.");
-#endif
}
static int measure_keyslot(
const char *mechanism,
int keyslot) {
-#if HAVE_TPM2
int r;
-#endif
+
assert(cd);
assert(name);
return 0;
}
-#if HAVE_TPM2
r = efi_measured_os(LOG_WARNING);
if (r < 0)
return r;
return 0;
}
- _cleanup_(tpm2_context_unrefp) Tpm2Context *c = NULL;
- r = tpm2_context_new_or_warn(arg_tpm2_device, &c);
- if (r < 0)
- return r;
-
_cleanup_free_ char *escaped = NULL;
escaped = xescape(name, ":"); /* avoid ambiguity around ":" once we join things below */
if (!escaped)
if (!s)
return log_oom();
- r = tpm2_nvpcr_extend_bytes(
- c,
- /* session= */ NULL,
- arg_tpm2_measure_keyslot_nvpcr,
- &IOVEC_MAKE_STRING(s),
- /* secret= */ NULL,
- TPM2_EVENT_KEYSLOT,
- s);
+ r = pcrextend_nvpcr_now(arg_tpm2_measure_keyslot_nvpcr, s, "keyslot");
if (r < 0)
return log_error_errno(r, "Could not extend NvPCR: %m");
- log_struct(LOG_INFO,
- "MESSAGE_ID=" SD_MESSAGE_TPM_NVPCR_EXTEND_STR,
- LOG_MESSAGE("Successfully extended NvPCR index '%s' with '%s'.", arg_tpm2_measure_keyslot_nvpcr, s),
- "MEASURING=%s", s,
- "NVPCR=%s", arg_tpm2_measure_keyslot_nvpcr);
-
return 0;
-#else
- return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "TPM2 support disabled, not measuring keyslot.");
-#endif
}
static int log_external_activation(int r, const char *volume) {
#include "tpm2-pcr.h"
#include "user-record.h"
-static int pcrextend_pcr_now(unsigned pcr, const char *word, const struct iovec *secret, const char *event) {
+int pcrextend_pcr_now(unsigned pcr, const char *word, const struct iovec *secret, const char *event) {
#if HAVE_TPM2
int r;
#endif
}
-static int pcrextend_nvpcr_now(const char *nvpcr, const char *word, const char *event) {
+int pcrextend_nvpcr_now(const char *nvpcr, const char *word, const char *event) {
#if HAVE_TPM2
int r;
+ assert(nvpcr);
+ assert(word);
+
_cleanup_(sd_varlink_unrefp) sd_varlink *vl = NULL;
r = sd_varlink_connect_address(&vl, "/run/systemd/io.systemd.PCRExtend");
if (r < 0)
#include "forward.h"
+int pcrextend_pcr_now(unsigned pcr, const char *word, const struct iovec *secret, const char *event);
+int pcrextend_nvpcr_now(const char *nvpcr, const char *word, const char *event);
+
int pcrextend_file_system_word(const char *path, char **ret, char **ret_normalized_path);
int pcrextend_machine_id_word(char **ret);
int pcrextend_product_id_word(char **ret);
--- /dev/null
+#!/usr/bin/env bash
+# SPDX-License-Identifier: LGPL-2.1-or-later
+set -eux
+set -o pipefail
+
+# Tests that systemd-cryptsetup's tpm2-measure-pcr= option measures the volume key
+# through the io.systemd.PCRExtend Varlink service.
+#
+# Note: the tpm2-measure-keyslot-nvpcr= (NvPCR) path is intentionally not covered here. NvPCRs use a
+# signed PCR policy that must be anchored first (see TEST-70-TPM2.nvpcr.sh), which is heavy setup
+# orthogonal to what this test checks; the NvPCR extend-via-pcrextend path is already covered there.
+
+# shellcheck source=test/units/util.sh
+. "$(dirname "$0")"/util.sh
+
+export SYSTEMD_LOG_LEVEL=debug
+
+if ! command -v systemd-cryptsetup >/dev/null || ! tpm_has_pcr sha256 15; then
+ echo "systemd-cryptsetup or PCR 15 (sha256) not available, skipping cryptsetup measurement test"
+ exit 0
+fi
+
+IMAGE=""
+
+at_exit() {
+ if [[ $? -ne 0 ]]; then
+ # Dump the event log on failure, to ease debugging
+ jq --seq --slurp </run/log/systemd/tpm2-measure.log || :
+ fi
+
+ set +e
+
+ systemd-cryptsetup detach test-volume
+ rm -rf /run/systemd/system/systemd-pcrextend.socket.d
+ systemctl daemon-reload
+ systemctl restart systemd-pcrextend.socket
+ rm -f "${IMAGE:-}" /tmp/passphrase /tmp/vk /tmp/vk-hmac.bin \
+ /tmp/oldpcr15 /tmp/newpcr15 /tmp/measure-bank.log
+}
+
+trap at_exit EXIT
+
+# The socket carries ConditionSecurity=measured-os, which does not hold in the
+# test VM, so the Varlink service would never activate. Drop the condition so
+# systemd-cryptsetup can reach it, exactly like TEST-70-TPM2.pcrextend.sh does.
+mkdir -p /run/systemd/system/systemd-pcrextend.socket.d
+cat >/run/systemd/system/systemd-pcrextend.socket.d/50-no-condition.conf <<EOF
+[Unit]
+ConditionSecurity=
+EOF
+systemctl daemon-reload
+systemctl restart systemd-pcrextend.socket
+
+# Prepare a fresh LUKS2 volume unlocked by a passphrase keyfile
+IMAGE="$(mktemp /tmp/systemd-cryptsetup-measure-XXX.IMAGE)"
+truncate -s 20M "$IMAGE"
+echo -n passphrase >/tmp/passphrase
+chmod 0600 /tmp/passphrase
+cryptsetup luksFormat -q --pbkdf pbkdf2 --pbkdf-force-iterations 1000 --use-urandom "$IMAGE" /tmp/passphrase
+
+UUID="$(cryptsetup luksUUID "$IMAGE")"
+
+# Extract the raw volume key so we can recompute the expected HMAC below. The
+# volume key is measured as HMAC(volume_key, prefix) rather than a plain hash
+# (see cryptsetup_get_volume_key_prefix()/cryptsetup_get_volume_key_id()).
+cryptsetup luksDump -q --dump-volume-key --volume-key-file=/tmp/vk --key-file=/tmp/passphrase "$IMAGE"
+VK_HEX="$(od -An -v -tx1 /tmp/vk | tr -d ' \n')"
+
+# prefix = "cryptsetup:" <escaped volume name> ":" <LUKS UUID>; "test-volume"
+# contains no ':' so it is unescaped.
+PREFIX="cryptsetup:test-volume:$UUID"
+
+# Expected measured digest for the sha256 bank: HMAC-SHA256(volume_key, prefix)
+printf '%s' "$PREFIX" | openssl dgst -binary -sha256 -mac HMAC -macopt "hexkey:$VK_HEX" >/tmp/vk-hmac.bin
+DIGEST_EXPECTED="$(od -An -v -tx1 /tmp/vk-hmac.bin | tr -d ' \n')"
+
+# Remember the current event log length so we can index the record we add.
+# (json-seq: each record is RS(0x1e)-prefixed, LF-suffixed.) The log is created
+# lazily on the first measurement, and this subtest may be the first thing to
+# measure (e.g. when run in isolation), so treat an absent log as zero records.
+RECORD_COUNT=0
+if [[ -f /run/log/systemd/tpm2-measure.log ]]; then
+ RECORD_COUNT="$(jq --seq --slurp '. | length' </run/log/systemd/tpm2-measure.log | tr -d '\036')"
+fi
+
+tpm2_pcrread sha256:15 -Q -o /tmp/oldpcr15
+
+# Activate with measurement enabled. Unlock is via the keyfile (no TPM unlock),
+# to prove measurement is independent of the unlock mechanism.
+SYSTEMD_FORCE_MEASURE=1 systemd-cryptsetup attach test-volume "$IMAGE" /tmp/passphrase \
+ tpm2-measure-pcr=15,headless=1
+
+tpm2_pcrread sha256:15 -Q -o /tmp/newpcr15
+
+# The TPM PCR 15 must have been extended with the HMAC:
+# new = sha256(old || HMAC(volume_key, prefix))
+diff /tmp/newpcr15 \
+ <(cat /tmp/oldpcr15 /tmp/vk-hmac.bin | openssl dgst -binary -sha256)
+
+# The volume-key measurement is the record we just added (the first one past RECORD_COUNT).
+test "$(jq --seq --slurp ".[$RECORD_COUNT].pcr" </run/log/systemd/tpm2-measure.log)" == "$(printf '\x1e15')"
+DIGEST_CURRENT="$(jq --seq --slurp --raw-output ".[$RECORD_COUNT].digests[] | select(.hashAlg == \"sha256\").digest" </run/log/systemd/tpm2-measure.log)"
+test "$DIGEST_CURRENT" == "$DIGEST_EXPECTED"
+
+systemd-cryptsetup detach test-volume
+
+# The deprecated tpm2-measure-bank= option must warn but not fail.
+SYSTEMD_FORCE_MEASURE=1 systemd-cryptsetup attach test-volume "$IMAGE" /tmp/passphrase \
+ tpm2-measure-pcr=15,tpm2-measure-bank=sha256,headless=1 |& tee /tmp/measure-bank.log
+systemd-cryptsetup detach test-volume
+grep -i "deprecated" /tmp/measure-bank.log >/dev/null
projects / thirdparty / systemd.git / commitdiff
