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cryptenroll: add support for TPM2 enrolling

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This commit is contained in:
Lennart Poettering 2020-11-28 15:27:34 +01:00
parent 2d64d2b955
commit 5e521624f2
8 changed files with 1279 additions and 0 deletions
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18
meson.build
View File

@ -1185,6 +1185,17 @@ else
endif endif
conf.set10('HAVE_LIBFIDO2', have) conf.set10('HAVE_LIBFIDO2', have)
want_tpm2 = get_option('tpm2')
if want_tpm2 != 'false' and not skip_deps
tpm2 = dependency('tss2-esys tss2-rc tss2-mu',
required : want_tpm2 == 'true')
have = tpm2.found()
else
have = false
tpm2 = []
endif
conf.set10('HAVE_TPM2', have)
want_elfutils = get_option('elfutils') want_elfutils = get_option('elfutils')
if want_elfutils != 'false' and not skip_deps if want_elfutils != 'false' and not skip_deps
libdw = dependency('libdw', libdw = dependency('libdw',
@ -2428,6 +2439,7 @@ if conf.get('HAVE_LIBCRYPTSETUP') == 1
src/cryptenroll/cryptenroll-pkcs11.h src/cryptenroll/cryptenroll-pkcs11.h
src/cryptenroll/cryptenroll-recovery.c src/cryptenroll/cryptenroll-recovery.c
src/cryptenroll/cryptenroll-recovery.h src/cryptenroll/cryptenroll-recovery.h
src/cryptenroll/cryptenroll-tpm2.h
src/cryptenroll/cryptenroll.c src/cryptenroll/cryptenroll.c
'''.split()) '''.split())
@ -2439,12 +2451,17 @@ if conf.get('HAVE_LIBCRYPTSETUP') == 1
systemd_cryptenroll_sources += files('src/cryptenroll/cryptenroll-fido2.c') systemd_cryptenroll_sources += files('src/cryptenroll/cryptenroll-fido2.c')
endif endif
if conf.get('HAVE_TPM2') == 1
systemd_cryptenroll_sources += files('src/cryptenroll/cryptenroll-tpm2.c')
endif
executable( executable(
'systemd-cryptenroll', 'systemd-cryptenroll',
systemd_cryptenroll_sources, systemd_cryptenroll_sources,
include_directories : includes, include_directories : includes,
link_with : [libshared], link_with : [libshared],
dependencies : [libcryptsetup, dependencies : [libcryptsetup,
libdl,
libopenssl, libopenssl,
libp11kit], libp11kit],
install_rpath : rootlibexecdir, install_rpath : rootlibexecdir,
@ -3770,6 +3787,7 @@ foreach tuple : [
['libfdisk'], ['libfdisk'],
['p11kit'], ['p11kit'],
['libfido2'], ['libfido2'],
['tpm2'],
['AUDIT'], ['AUDIT'],
['IMA'], ['IMA'],
['AppArmor'], ['AppArmor'],

2
meson_options.txt
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@ -327,6 +327,8 @@ option('p11kit', type : 'combo', choices : ['auto', 'true', 'false'],
description : 'p11kit support') description : 'p11kit support')
option('libfido2', type : 'combo', choices : ['auto', 'true', 'false'], option('libfido2', type : 'combo', choices : ['auto', 'true', 'false'],
description : 'FIDO2 support') description : 'FIDO2 support')
option('tpm2', type : 'combo', choices : ['auto', 'true', 'false'],
description : 'TPM2 support')
option('elfutils', type : 'combo', choices : ['auto', 'true', 'false'], option('elfutils', type : 'combo', choices : ['auto', 'true', 'false'],
description : 'elfutils support') description : 'elfutils support')
option('zlib', type : 'combo', choices : ['auto', 'true', 'false'], option('zlib', type : 'combo', choices : ['auto', 'true', 'false'],

131
src/cryptenroll/cryptenroll-tpm2.c Normal file
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@ -0,0 +1,131 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "alloc-util.h"
#include "cryptenroll-tpm2.h"
#include "hexdecoct.h"
#include "json.h"
#include "memory-util.h"
#include "tpm2-util.h"
static int search_policy_hash(
struct crypt_device *cd,
const void *hash,
size_t hash_size) {
int r;
assert(cd);
assert(hash || hash_size == 0);
if (hash_size == 0)
return 0;
for (int token = 0; token < LUKS2_TOKENS_MAX; token ++) {
_cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
_cleanup_free_ void *thash = NULL;
size_t thash_size = 0;
int keyslot;
JsonVariant *w;
r = cryptsetup_get_token_as_json(cd, token, "systemd-tpm2", &v);
if (IN_SET(r, -ENOENT, -EINVAL, -EMEDIUMTYPE))
continue;
if (r < 0)
return log_error_errno(r, "Failed to read JSON token data off disk: %m");
keyslot = cryptsetup_get_keyslot_from_token(v);
if (keyslot < 0)
return log_error_errno(keyslot, "Failed to determine keyslot of JSON token: %m");
w = json_variant_by_key(v, "tpm2-policy-hash");
if (!w || !json_variant_is_string(w))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"TPM2 token data lacks 'tpm2-policy-hash' field.");
r = unhexmem(json_variant_string(w), (size_t) -1, &thash, &thash_size);
if (r < 0)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Invalid base64 data in 'tpm2-policy-hash' field.");
if (memcmp_nn(hash, hash_size, thash, thash_size) == 0)
return keyslot; /* Found entry with same hash. */
}
return -ENOENT; /* Not found */
}
int enroll_tpm2(struct crypt_device *cd,
const void *volume_key,
size_t volume_key_size,
const char *device,
uint32_t pcr_mask) {
_cleanup_(erase_and_freep) void *secret = NULL, *secret2 = NULL;
_cleanup_(json_variant_unrefp) JsonVariant *v = NULL, *a = NULL;
_cleanup_(erase_and_freep) char *base64_encoded = NULL;
size_t secret_size, secret2_size, blob_size, hash_size;
_cleanup_free_ void *blob = NULL, *hash = NULL;
const char *node;
int r, keyslot;
assert(cd);
assert(volume_key);
assert(volume_key_size > 0);
assert(pcr_mask < (1U << TPM2_PCRS_MAX)); /* Support 24 PCR banks */
assert_se(node = crypt_get_device_name(cd));
r = tpm2_seal(device, pcr_mask, &secret, &secret_size, &blob, &blob_size, &hash, &hash_size);
if (r < 0)
return r;
/* Let's see if we already have this specific PCR policy hash enrolled, if so, exit early. */
r = search_policy_hash(cd, hash, hash_size);
if (r == -ENOENT)
log_debug_errno(r, "PCR policy hash not yet enrolled, enrolling now.");
else if (r < 0)
return r;
else {
log_info("This PCR set is already enrolled, executing no operation.");
return r; /* return existing keyslot, so that wiping won't kill it */
}
/* Quick verification that everything is in order, we are not in a hurry after all. */
log_debug("Unsealing for verification...");
r = tpm2_unseal(device, pcr_mask, blob, blob_size, hash, hash_size, &secret2, &secret2_size);
if (r < 0)
return r;
if (memcmp_nn(secret, secret_size, secret2, secret2_size) != 0)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE), "TPM2 seal/unseal verification failed.");
/* let's base64 encode the key to use, for compat with homed (and it's easier to every type it in by keyboard, if that might end up being necessary. */
r = base64mem(secret, secret_size, &base64_encoded);
if (r < 0)
return log_error_errno(r, "Failed to base64 encode secret key: %m");
r = cryptsetup_set_minimal_pbkdf(cd);
if (r < 0)
return log_error_errno(r, "Failed to set minimal PBKDF: %m");
keyslot = crypt_keyslot_add_by_volume_key(
cd,
CRYPT_ANY_SLOT,
volume_key,
volume_key_size,
base64_encoded,
strlen(base64_encoded));
if (keyslot < 0)
return log_error_errno(keyslot, "Failed to add new TPM2 key to %s: %m", node);
r = tpm2_make_luks2_json(keyslot, pcr_mask, blob, blob_size, hash, hash_size, &v);
if (r < 0)
return log_error_errno(r, "Failed to prepare TPM2 JSON token object: %m");
r = cryptsetup_add_token_json(cd, v);
if (r < 0)
return log_error_errno(r, "Failed to add TPM2 JSON token to LUKS2 header: %m");
log_info("New TPM2 token enrolled as key slot %i.", keyslot);
return keyslot;
}

16
src/cryptenroll/cryptenroll-tpm2.h Normal file
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@ -0,0 +1,16 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once
#include <sys/types.h>
#include "cryptsetup-util.h"
#include "log.h"
#if HAVE_TPM2
int enroll_tpm2(struct crypt_device *cd, const void *volume_key, size_t volume_key_size, const char *device, uint32_t pcr_mask);
#else
static inline int enroll_tpm2(struct crypt_device *cd, const void *volume_key, size_t volume_key_size, const char *device, uint32_t pcr_mask) {
return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
"TPM2 key enrollment not supported.");
}
#endif

61
src/cryptenroll/cryptenroll.c
View File

@ -7,22 +7,26 @@
#include "cryptenroll-password.h" #include "cryptenroll-password.h"
#include "cryptenroll-pkcs11.h" #include "cryptenroll-pkcs11.h"
#include "cryptenroll-recovery.h" #include "cryptenroll-recovery.h"
#include "cryptenroll-tpm2.h"
#include "cryptsetup-util.h" #include "cryptsetup-util.h"
#include "escape.h" #include "escape.h"
#include "libfido2-util.h" #include "libfido2-util.h"
#include "main-func.h" #include "main-func.h"
#include "memory-util.h" #include "memory-util.h"
#include "parse-util.h"
#include "path-util.h" #include "path-util.h"
#include "pkcs11-util.h" #include "pkcs11-util.h"
#include "pretty-print.h" #include "pretty-print.h"
#include "strv.h" #include "strv.h"
#include "terminal-util.h" #include "terminal-util.h"
#include "tpm2-util.h"
typedef enum EnrollType { typedef enum EnrollType {
ENROLL_PASSWORD, ENROLL_PASSWORD,
ENROLL_RECOVERY, ENROLL_RECOVERY,
ENROLL_PKCS11, ENROLL_PKCS11,
ENROLL_FIDO2, ENROLL_FIDO2,
ENROLL_TPM2,
_ENROLL_TYPE_MAX, _ENROLL_TYPE_MAX,
_ENROLL_TYPE_INVALID = -1, _ENROLL_TYPE_INVALID = -1,
} EnrollType; } EnrollType;
@ -31,6 +35,7 @@ static EnrollType arg_enroll_type = _ENROLL_TYPE_INVALID;
static char *arg_pkcs11_token_uri = NULL; static char *arg_pkcs11_token_uri = NULL;
static char *arg_fido2_device = NULL; static char *arg_fido2_device = NULL;
static char *arg_tpm2_device = NULL; static char *arg_tpm2_device = NULL;
static uint32_t arg_tpm2_pcr_mask = UINT32_MAX;
static char *arg_node = NULL; static char *arg_node = NULL;
STATIC_DESTRUCTOR_REGISTER(arg_pkcs11_token_uri, freep); STATIC_DESTRUCTOR_REGISTER(arg_pkcs11_token_uri, freep);
@ -56,6 +61,10 @@ static int help(void) {
" Specify PKCS#11 security token URI\n" " Specify PKCS#11 security token URI\n"
" --fido2-device=PATH\n" " --fido2-device=PATH\n"
" Enroll a FIDO2-HMAC security token\n" " Enroll a FIDO2-HMAC security token\n"
" --tpm2-device=PATH\n"
" Enroll a TPM2 device\n"
" --tpm2-pcrs=PCR1,PCR2,PCR3,…\n"
" Specifiy TPM2 PCRs to seal against\n"
"\nSee the %s for details.\n" "\nSee the %s for details.\n"
, program_invocation_short_name , program_invocation_short_name
, ansi_highlight(), ansi_normal() , ansi_highlight(), ansi_normal()
@ -73,6 +82,8 @@ static int parse_argv(int argc, char *argv[]) {
ARG_RECOVERY_KEY, ARG_RECOVERY_KEY,
ARG_PKCS11_TOKEN_URI, ARG_PKCS11_TOKEN_URI,
ARG_FIDO2_DEVICE, ARG_FIDO2_DEVICE,
ARG_TPM2_DEVICE,
ARG_TPM2_PCRS,
}; };
static const struct option options[] = { static const struct option options[] = {
@ -82,6 +93,8 @@ static int parse_argv(int argc, char *argv[]) {
{ "recovery-key", no_argument, NULL, ARG_RECOVERY_KEY }, { "recovery-key", no_argument, NULL, ARG_RECOVERY_KEY },
{ "pkcs11-token-uri", required_argument, NULL, ARG_PKCS11_TOKEN_URI }, { "pkcs11-token-uri", required_argument, NULL, ARG_PKCS11_TOKEN_URI },
{ "fido2-device", required_argument, NULL, ARG_FIDO2_DEVICE }, { "fido2-device", required_argument, NULL, ARG_FIDO2_DEVICE },
{ "tpm2-device", required_argument, NULL, ARG_TPM2_DEVICE },
{ "tpm2-pcrs", required_argument, NULL, ARG_TPM2_PCRS },
{} {}
}; };
@ -169,6 +182,47 @@ static int parse_argv(int argc, char *argv[]) {
break; break;
} }
case ARG_TPM2_DEVICE: {
_cleanup_free_ char *device = NULL;
if (streq(optarg, "list"))
return tpm2_list_devices();
if (arg_enroll_type >= 0 || arg_tpm2_device)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Multiple operations specified at once, refusing.");
if (!streq(optarg, "auto")) {
device = strdup(optarg);
if (!device)
return log_oom();
}
arg_enroll_type = ENROLL_TPM2;
arg_tpm2_device = TAKE_PTR(device);
break;
}
case ARG_TPM2_PCRS: {
uint32_t mask;
if (isempty(optarg)) {
arg_tpm2_pcr_mask = 0;
break;
}
r = tpm2_parse_pcrs(optarg, &mask);
if (r < 0)
return r;
if (arg_tpm2_pcr_mask == UINT32_MAX)
arg_tpm2_pcr_mask = mask;
else
arg_tpm2_pcr_mask |= mask;
break;
}
case '?': case '?':
return -EINVAL; return -EINVAL;
@ -193,6 +247,9 @@ static int parse_argv(int argc, char *argv[]) {
if (r < 0) if (r < 0)
return r; return r;
if (arg_tpm2_pcr_mask == UINT32_MAX)
arg_tpm2_pcr_mask = TPM2_PCR_MASK_DEFAULT;
return 1; return 1;
} }
@ -348,6 +405,10 @@ static int run(int argc, char *argv[]) {
r = enroll_fido2(cd, vk, vks, arg_fido2_device); r = enroll_fido2(cd, vk, vks, arg_fido2_device);
break; break;
case ENROLL_TPM2:
r = enroll_tpm2(cd, vk, vks, arg_tpm2_device, arg_tpm2_pcr_mask);
break;
default: default:
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Operation not implemented yet."); return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Operation not implemented yet.");
} }

2
src/shared/meson.build
View File

@ -237,6 +237,8 @@ shared_sources = files('''
tmpfile-util-label.h tmpfile-util-label.h
tomoyo-util.c tomoyo-util.c
tomoyo-util.h tomoyo-util.h
tpm2-util.c
tpm2-util.h
udev-util.c udev-util.c
udev-util.h udev-util.h
uid-range.c uid-range.c

998
src/shared/tpm2-util.c Normal file
View File

@ -0,0 +1,998 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "extract-word.h"
#include "parse-util.h"
#include "tpm2-util.h"
#if HAVE_TPM2
#include "alloc-util.h"
#include "dirent-util.h"
#include "dlfcn-util.h"
#include "fd-util.h"
#include "format-table.h"
#include "fs-util.h"
#include "hexdecoct.h"
#include "memory-util.h"
#include "random-util.h"
#include "time-util.h"
static void *libtss2_esys_dl = NULL;
static void *libtss2_rc_dl = NULL;
static void *libtss2_mu_dl = NULL;
TSS2_RC (*sym_Esys_Create)(ESYS_CONTEXT *esysContext, ESYS_TR parentHandle, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, const TPM2B_SENSITIVE_CREATE *inSensitive, const TPM2B_PUBLIC *inPublic, const TPM2B_DATA *outsideInfo, const TPML_PCR_SELECTION *creationPCR, TPM2B_PRIVATE **outPrivate, TPM2B_PUBLIC **outPublic, TPM2B_CREATION_DATA **creationData, TPM2B_DIGEST **creationHash, TPMT_TK_CREATION **creationTicket) = NULL;
TSS2_RC (*sym_Esys_CreatePrimary)(ESYS_CONTEXT *esysContext, ESYS_TR primaryHandle, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, const TPM2B_SENSITIVE_CREATE *inSensitive, const TPM2B_PUBLIC *inPublic, const TPM2B_DATA *outsideInfo, const TPML_PCR_SELECTION *creationPCR, ESYS_TR *objectHandle, TPM2B_PUBLIC **outPublic, TPM2B_CREATION_DATA **creationData, TPM2B_DIGEST **creationHash, TPMT_TK_CREATION **creationTicket) = NULL;
void (*sym_Esys_Finalize)(ESYS_CONTEXT **context) = NULL;
TSS2_RC (*sym_Esys_FlushContext)(ESYS_CONTEXT *esysContext, ESYS_TR flushHandle) = NULL;
void (*sym_Esys_Free)(void *ptr) = NULL;
TSS2_RC (*sym_Esys_GetRandom)(ESYS_CONTEXT *esysContext, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, UINT16 bytesRequested, TPM2B_DIGEST **randomBytes) = NULL;
TSS2_RC (*sym_Esys_Initialize)(ESYS_CONTEXT **esys_context, TSS2_TCTI_CONTEXT *tcti, TSS2_ABI_VERSION *abiVersion) = NULL;
TSS2_RC (*sym_Esys_Load)(ESYS_CONTEXT *esysContext, ESYS_TR parentHandle, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, const TPM2B_PRIVATE *inPrivate, const TPM2B_PUBLIC *inPublic, ESYS_TR *objectHandle) = NULL;
TSS2_RC (*sym_Esys_PolicyGetDigest)(ESYS_CONTEXT *esysContext, ESYS_TR policySession, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, TPM2B_DIGEST **policyDigest) = NULL;
TSS2_RC (*sym_Esys_PolicyPCR)(ESYS_CONTEXT *esysContext, ESYS_TR policySession, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, const TPM2B_DIGEST *pcrDigest, const TPML_PCR_SELECTION *pcrs) = NULL;
TSS2_RC (*sym_Esys_StartAuthSession)(ESYS_CONTEXT *esysContext, ESYS_TR tpmKey, ESYS_TR bind, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, const TPM2B_NONCE *nonceCaller, TPM2_SE sessionType, const TPMT_SYM_DEF *symmetric, TPMI_ALG_HASH authHash, ESYS_TR *sessionHandle) = NULL;
TSS2_RC (*sym_Esys_Startup)(ESYS_CONTEXT *esysContext, TPM2_SU startupType) = NULL;
TSS2_RC (*sym_Esys_Unseal)(ESYS_CONTEXT *esysContext, ESYS_TR itemHandle, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, TPM2B_SENSITIVE_DATA **outData) = NULL;
const char* (*sym_Tss2_RC_Decode)(TSS2_RC rc) = NULL;
TSS2_RC (*sym_Tss2_MU_TPM2B_PRIVATE_Marshal)(TPM2B_PRIVATE const *src, uint8_t buffer[], size_t buffer_size, size_t *offset) = NULL;
TSS2_RC (*sym_Tss2_MU_TPM2B_PRIVATE_Unmarshal)(uint8_t const buffer[], size_t buffer_size, size_t *offset, TPM2B_PRIVATE *dest) = NULL;
TSS2_RC (*sym_Tss2_MU_TPM2B_PUBLIC_Marshal)(TPM2B_PUBLIC const *src, uint8_t buffer[], size_t buffer_size, size_t *offset) = NULL;
TSS2_RC (*sym_Tss2_MU_TPM2B_PUBLIC_Unmarshal)(uint8_t const buffer[], size_t buffer_size, size_t *offset, TPM2B_PUBLIC *dest) = NULL;
int dlopen_tpm2(void) {
int r, k = 0;
if (!libtss2_esys_dl) {
_cleanup_(dlclosep) void *dl = NULL;
dl = dlopen("libtss2-esys.so.0", RTLD_LAZY);
if (!dl)
return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
"TPM2 support is not installed: %s", dlerror());
r = dlsym_many_and_warn(
dl,
LOG_DEBUG,
DLSYM_ARG(Esys_Create),
DLSYM_ARG(Esys_CreatePrimary),
DLSYM_ARG(Esys_Finalize),
DLSYM_ARG(Esys_FlushContext),
DLSYM_ARG(Esys_Free),
DLSYM_ARG(Esys_GetRandom),
DLSYM_ARG(Esys_Initialize),
DLSYM_ARG(Esys_Load),
DLSYM_ARG(Esys_PolicyGetDigest),
DLSYM_ARG(Esys_PolicyPCR),
DLSYM_ARG(Esys_StartAuthSession),
DLSYM_ARG(Esys_Startup),
DLSYM_ARG(Esys_Unseal),
NULL);
if (r < 0)
return r;
libtss2_esys_dl = TAKE_PTR(dl);
k++;
}
if (!libtss2_rc_dl) {
_cleanup_(dlclosep) void *dl = NULL;
dl = dlopen("libtss2-rc.so.0", RTLD_LAZY);
if (!dl)
return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
"TPM2 support is not installed: %s", dlerror());
r = dlsym_many_and_warn(
dl,
LOG_DEBUG,
DLSYM_ARG(Tss2_RC_Decode),
NULL);
if (r < 0)
return r;
libtss2_rc_dl = TAKE_PTR(dl);
k++;
}
if (!libtss2_mu_dl) {
_cleanup_(dlclosep) void *dl = NULL;
dl = dlopen("libtss2-mu.so.0", RTLD_LAZY);
if (!dl)
return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
"TPM2 support is not installed: %s", dlerror());
r = dlsym_many_and_warn(
dl,
LOG_DEBUG,
DLSYM_ARG(Tss2_MU_TPM2B_PRIVATE_Marshal),
DLSYM_ARG(Tss2_MU_TPM2B_PRIVATE_Unmarshal),
DLSYM_ARG(Tss2_MU_TPM2B_PUBLIC_Marshal),
DLSYM_ARG(Tss2_MU_TPM2B_PUBLIC_Unmarshal),
NULL);
if (r < 0)
return r;
libtss2_mu_dl = TAKE_PTR(dl);
k++;
}
return k;
}
struct tpm2_context {
ESYS_CONTEXT *esys_context;
void *tcti_dl;
TSS2_TCTI_CONTEXT *tcti_context;
};
static void tpm2_context_destroy(struct tpm2_context *c) {
assert(c);
if (c->esys_context)
sym_Esys_Finalize(&c->esys_context);
c->tcti_context = mfree(c->tcti_context);
if (c->tcti_dl) {
dlclose(c->tcti_dl);
c->tcti_dl = NULL;
}
}
static inline void Esys_Finalize_wrapper(ESYS_CONTEXT **c) {
/* A wrapper around Esys_Finalize() for use with _cleanup_(). Only reasons we need this wrapper is
* because the function itself warn logs if we'd pass a pointer to NULL, and we don't want that. */
if (*c)
sym_Esys_Finalize(c);
}
static inline void Esys_Freep(void *p) {
if (*(void**) p)
sym_Esys_Free(*(void**) p);
}
static ESYS_TR flush_context_verbose(ESYS_CONTEXT *c, ESYS_TR handle) {
TSS2_RC rc;
if (!c || handle == ESYS_TR_NONE)
return ESYS_TR_NONE;
rc = sym_Esys_FlushContext(c, handle);
if (rc != TSS2_RC_SUCCESS) /* We ignore failures here (besides debug logging), since this is called
* in error paths, where we cannot do anything about failures anymore. And
* when it is called in successful codepaths by this time we already did
* what we wanted to do, and got the results we wanted so there's no
* reason to make this fail more loudly than necessary. */
log_debug("Failed to get flush context of TPM, ignoring: %s", sym_Tss2_RC_Decode(rc));
return ESYS_TR_NONE;
}
static int tpm2_init(const char *device, struct tpm2_context *ret) {
_cleanup_(Esys_Finalize_wrapper) ESYS_CONTEXT *c = NULL;
_cleanup_free_ TSS2_TCTI_CONTEXT *tcti = NULL;
_cleanup_(dlclosep) void *dl = NULL;
TSS2_RC rc;
int r;
r = dlopen_tpm2();
if (r < 0)
return log_error_errno(r, "TPM2 support not installed: %m");
if (!device)
device = secure_getenv("SYSTEMD_TPM2_DEVICE");
if (device) {
const char *param, *driver, *fn;
const TSS2_TCTI_INFO* info;
TSS2_TCTI_INFO_FUNC func;
size_t sz = 0;
param = strchr(device, ':');
if (param) {
driver = strndupa(device, param - device);
param++;
} else {
driver = "device";
param = device;
}
fn = strjoina("libtss2-tcti-", driver, ".so.0");
dl = dlopen(fn, RTLD_NOW);
if (!dl)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE), "Failed to load %s: %s", fn, dlerror());
func = dlsym(dl, TSS2_TCTI_INFO_SYMBOL);
if (!func)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to find TCTI info symbol " TSS2_TCTI_INFO_SYMBOL ": %s",
dlerror());
info = func();
if (!info)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE), "Unable to get TCTI info data.");
log_debug("Loaded TCTI module '%s' (%s) [Version %" PRIu32 "]", info->name, info->description, info->version);
rc = info->init(NULL, &sz, NULL);
if (rc != TPM2_RC_SUCCESS)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to initialize TCTI context: %s", sym_Tss2_RC_Decode(rc));
tcti = malloc0(sz);
if (!tcti)
return log_oom();
rc = info->init(tcti, &sz, device);
if (rc != TPM2_RC_SUCCESS)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to initialize TCTI context: %s", sym_Tss2_RC_Decode(rc));
}
rc = sym_Esys_Initialize(&c, tcti, NULL);
if (rc != TSS2_RC_SUCCESS)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to initialize TPM context: %s", sym_Tss2_RC_Decode(rc));
rc = sym_Esys_Startup(c, TPM2_SU_CLEAR);
if (rc == TPM2_RC_INITIALIZE)
log_debug("TPM already started up.");
else if (rc == TSS2_RC_SUCCESS)
log_debug("TPM successfully started up.");
else
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to start up TPM: %s", sym_Tss2_RC_Decode(rc));
*ret = (struct tpm2_context) {
.esys_context = TAKE_PTR(c),
.tcti_context = TAKE_PTR(tcti),
.tcti_dl = TAKE_PTR(dl),
};
return 0;
}
static int tpm2_credit_random(ESYS_CONTEXT *c) {
size_t rps, done = 0;
TSS2_RC rc;
int r;
assert(c);
/* Pulls some entropy from the TPM and adds it into the kernel RNG pool. That way we can say that the
* key we will ultimately generate with the kernel random pool is at least as good as the TPM's RNG,
* but likely better. Note that we don't trust the TPM RNG very much, hence do not actually credit
* any entropy. */
for (rps = random_pool_size(); rps > 0;) {
_cleanup_(Esys_Freep) TPM2B_DIGEST *buffer = NULL;
rc = sym_Esys_GetRandom(
c,
ESYS_TR_NONE,
ESYS_TR_NONE,
ESYS_TR_NONE,
MIN(rps, 32U), /* 32 is supposedly a safe choice, given that AES 256bit keys are this long, and TPM2 baseline requires support for those. */
&buffer);
if (rc != TSS2_RC_SUCCESS)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to acquire entropy from TPM: %s", sym_Tss2_RC_Decode(rc));
if (buffer->size == 0)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Zero-sized entropy returned from TPM.");
r = random_write_entropy(-1, buffer->buffer, buffer->size, false);
if (r < 0)
return log_error_errno(r, "Failed wo write entropy to kernel: %m");
done += buffer->size;
rps = LESS_BY(rps, buffer->size);
}
log_debug("Added %zu bytes of entropy to the kernel random pool.", done);
return 0;
}
static int tpm2_make_primary(
ESYS_CONTEXT *c,
ESYS_TR *ret_primary) {
static const TPM2B_SENSITIVE_CREATE primary_sensitive = {};
static const TPM2B_PUBLIC primary_template = {
.size = sizeof(TPMT_PUBLIC),
.publicArea = {
.type = TPM2_ALG_ECC,
.nameAlg = TPM2_ALG_SHA256,
.objectAttributes = TPMA_OBJECT_RESTRICTED|TPMA_OBJECT_DECRYPT|TPMA_OBJECT_FIXEDTPM|TPMA_OBJECT_FIXEDPARENT|TPMA_OBJECT_SENSITIVEDATAORIGIN|TPMA_OBJECT_USERWITHAUTH,
.parameters = {
.eccDetail = {
.symmetric = {
.algorithm = TPM2_ALG_AES,
.keyBits.aes = 128,
.mode.aes = TPM2_ALG_CFB,
},
.scheme.scheme = TPM2_ALG_NULL,
.curveID = TPM2_ECC_NIST_P256,
.kdf.scheme = TPM2_ALG_NULL,
},
},
},
};
static const TPML_PCR_SELECTION creation_pcr = {};
ESYS_TR primary = ESYS_TR_NONE;
TSS2_RC rc;
log_debug("Creating primary key on TPM.");
rc = sym_Esys_CreatePrimary(
c,
ESYS_TR_RH_OWNER,
ESYS_TR_PASSWORD,
ESYS_TR_NONE,
ESYS_TR_NONE,
&primary_sensitive,
&primary_template,
NULL,
&creation_pcr,
&primary,
NULL,
NULL,
NULL,
NULL);
if (rc != TSS2_RC_SUCCESS)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to generate primary key in TPM: %s", sym_Tss2_RC_Decode(rc));
log_debug("Successfully created primary key on TPM.");
*ret_primary = primary;
return 0;
}
static int tpm2_make_pcr_session(
ESYS_CONTEXT *c,
uint32_t pcr_mask,
ESYS_TR *ret_session,
TPM2B_DIGEST **ret_policy_digest) {
static const TPMT_SYM_DEF symmetric = {
.algorithm = TPM2_ALG_AES,
.keyBits = {
.aes = 128
},
.mode = {
.aes = TPM2_ALG_CFB,
}
};
TPML_PCR_SELECTION pcr_selection = {
.count = 1,
.pcrSelections[0].hash = TPM2_ALG_SHA256,
.pcrSelections[0].sizeofSelect = 3,
.pcrSelections[0].pcrSelect[0] = pcr_mask & 0xFF,
.pcrSelections[0].pcrSelect[1] = (pcr_mask >> 8) & 0xFF,
.pcrSelections[0].pcrSelect[2] = (pcr_mask >> 16) & 0xFF,
};
_cleanup_(Esys_Freep) TPM2B_DIGEST *policy_digest = NULL;
ESYS_TR session = ESYS_TR_NONE;
TSS2_RC rc;
int r;
assert(c);
log_debug("Starting authentication session.");
rc = sym_Esys_StartAuthSession(
c,
ESYS_TR_NONE,
ESYS_TR_NONE,
ESYS_TR_NONE,
ESYS_TR_NONE,
ESYS_TR_NONE,
NULL,
TPM2_SE_POLICY,
&symmetric,
TPM2_ALG_SHA256,
&session);
if (rc != TSS2_RC_SUCCESS)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to open session in TPM: %s", sym_Tss2_RC_Decode(rc));
log_debug("Configuring PCR policy.");
rc = sym_Esys_PolicyPCR(
c,
session,
ESYS_TR_NONE,
ESYS_TR_NONE,
ESYS_TR_NONE,
NULL,
&pcr_selection);
if (rc != TSS2_RC_SUCCESS) {
r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to add PCR policy to TPM: %s", sym_Tss2_RC_Decode(rc));
goto finish;
}
if (DEBUG_LOGGING || ret_policy_digest) {
log_debug("Acquiring policy digest.");
rc = sym_Esys_PolicyGetDigest(
c,
session,
ESYS_TR_NONE,
ESYS_TR_NONE,
ESYS_TR_NONE,
&policy_digest);
if (rc != TSS2_RC_SUCCESS) {
r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to get policy digest from TPM: %s", sym_Tss2_RC_Decode(rc));
goto finish;
}
if (DEBUG_LOGGING) {
_cleanup_free_ char *h = NULL;
h = hexmem(policy_digest->buffer, policy_digest->size);
if (!h) {
r = log_oom();
goto finish;
}
log_debug("Session policy digest: %s", h);
}
}
if (ret_session) {
*ret_session = session;
session = ESYS_TR_NONE;
}
if (ret_policy_digest)
*ret_policy_digest = TAKE_PTR(policy_digest);
r = 0;
finish:
session = flush_context_verbose(c, session);
return r;
}
int tpm2_seal(
const char *device,
uint32_t pcr_mask,
void **ret_secret,
size_t *ret_secret_size,
void **ret_blob,
size_t *ret_blob_size,
void **ret_pcr_hash,
size_t *ret_pcr_hash_size) {
_cleanup_(tpm2_context_destroy) struct tpm2_context c = {};
_cleanup_(Esys_Freep) TPM2B_DIGEST *policy_digest = NULL;
_cleanup_(Esys_Freep) TPM2B_PRIVATE *private = NULL;
_cleanup_(Esys_Freep) TPM2B_PUBLIC *public = NULL;
static const TPML_PCR_SELECTION creation_pcr = {};
_cleanup_(erase_and_freep) void *secret = NULL;
_cleanup_free_ void *blob = NULL, *hash = NULL;
TPM2B_SENSITIVE_CREATE hmac_sensitive;
ESYS_TR primary = ESYS_TR_NONE;
TPM2B_PUBLIC hmac_template;
size_t k, blob_size;
usec_t start;
TSS2_RC rc;
int r;
assert(ret_secret);
assert(ret_secret_size);
assert(ret_blob);
assert(ret_blob_size);
assert(ret_pcr_hash);
assert(ret_pcr_hash_size);
assert(pcr_mask < (UINT32_C(1) << TPM2_PCRS_MAX)); /* Support 24 PCR banks */
/* So here's what we do here: we connect to the TPM2 chip. It persistently contains a "seed" key that
* is randomized when the TPM2 is first initialized or reset and remains stable across boots. We
* generate a "primary" key pair derived from that (RSA). Given the seed remains fixed this will
* result in the same key pair whenever we specify the exact same parameters for it. We then create a
* PCR-bound policy session, which calculates a hash on the current PCR values of the indexes we
* specify. We then generate a randomized key on the host (which is the key we actually enroll in the
* LUKS2 keyslots), which we upload into the TPM2, where it is encrypted with the "primary" key,
* taking the PCR policy session into account. We then download the encrypted key from the TPM2
* ("sealing") and marshall it into binary form, which is ultimately placed in the LUKS2 JSON header.
*
* The TPM2 "seed" key and "primary" keys never leave the TPM2 chip (and cannot be extracted at
* all). The random key we enroll in LUKS2 we generate on the host using the Linux random device. It
* is stored in the LUKS2 JSON only in encrypted form with the "primary" key of the TPM2 chip, thus
* binding the unlocking to the TPM2 chip. */
start = now(CLOCK_MONOTONIC);
r = tpm2_init(device, &c);
if (r < 0)
return r;
r = tpm2_make_primary(c.esys_context, &primary);
if (r < 0)
return r;
r = tpm2_make_pcr_session(c.esys_context, pcr_mask, NULL, &policy_digest);
if (r < 0)
goto finish;
/* We use a keyed hash object (i.e. HMAC) to store the secret key we want to use for unlocking the
* LUKS2 volume with. We don't ever use for HMAC/keyed hash operations however, we just use it
* because it's a key type that is universally supported and suitable for symmetric binary blobs. */
hmac_template = (TPM2B_PUBLIC) {
.size = sizeof(TPMT_PUBLIC),
.publicArea = {
.type = TPM2_ALG_KEYEDHASH,
.nameAlg = TPM2_ALG_SHA256,
.objectAttributes = TPMA_OBJECT_FIXEDTPM | TPMA_OBJECT_FIXEDPARENT,
.parameters = {
.keyedHashDetail = {
.scheme.scheme = TPM2_ALG_NULL,
},
},
.unique = {
.keyedHash = {
.size = 32,
},
},
.authPolicy = *policy_digest,
},
};
hmac_sensitive = (TPM2B_SENSITIVE_CREATE) {
.size = sizeof(hmac_sensitive.sensitive),
.sensitive.data.size = 32,
};
assert(sizeof(hmac_sensitive.sensitive.data.buffer) >= hmac_sensitive.sensitive.data.size);
(void) tpm2_credit_random(c.esys_context);
log_debug("Generating secret key data.");
r = genuine_random_bytes(hmac_sensitive.sensitive.data.buffer, hmac_sensitive.sensitive.data.size, RANDOM_BLOCK);
if (r < 0) {
log_error_errno(r, "Failed to generate secret key: %m");
goto finish;
}
log_debug("Creating HMAC key.");
rc = sym_Esys_Create(
c.esys_context,
primary,
ESYS_TR_PASSWORD,
ESYS_TR_NONE,
ESYS_TR_NONE,
&hmac_sensitive,
&hmac_template,
NULL,
&creation_pcr,
&private,
&public,
NULL,
NULL,
NULL);
if (rc != TSS2_RC_SUCCESS) {
r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to generate HMAC key in TPM: %s", sym_Tss2_RC_Decode(rc));
goto finish;
}
secret = memdup(hmac_sensitive.sensitive.data.buffer, hmac_sensitive.sensitive.data.size);
explicit_bzero_safe(hmac_sensitive.sensitive.data.buffer, hmac_sensitive.sensitive.data.size);
if (!secret) {
r = log_oom();
goto finish;
}
log_debug("Marshalling private and public part of HMAC key.");
k = ALIGN8(sizeof(*private)) + ALIGN8(sizeof(*public)); /* Some roughly sensible start value */
for (;;) {
_cleanup_free_ void *buf = NULL;
size_t offset = 0;
buf = malloc(k);
if (!buf) {
r = log_oom();
goto finish;
}
rc = sym_Tss2_MU_TPM2B_PRIVATE_Marshal(private, buf, k, &offset);
if (rc == TSS2_RC_SUCCESS) {
rc = sym_Tss2_MU_TPM2B_PUBLIC_Marshal(public, buf, k, &offset);
if (rc == TSS2_RC_SUCCESS) {
blob = TAKE_PTR(buf);
blob_size = offset;
break;
}
}
if (rc != TSS2_MU_RC_INSUFFICIENT_BUFFER) {
r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to marshal private/public key: %s", sym_Tss2_RC_Decode(rc));
goto finish;
}
if (k > SIZE_MAX / 2) {
r = log_oom();
goto finish;
}
k *= 2;
}
hash = memdup(policy_digest->buffer, policy_digest->size);
if (!hash)
return log_oom();
if (DEBUG_LOGGING) {
char buf[FORMAT_TIMESPAN_MAX];
log_debug("Completed TPM2 key sealing in %s.", format_timespan(buf, sizeof(buf), now(CLOCK_MONOTONIC) - start, 1));
}
*ret_secret = TAKE_PTR(secret);
*ret_secret_size = hmac_sensitive.sensitive.data.size;
*ret_blob = TAKE_PTR(blob);
*ret_blob_size = blob_size;
*ret_pcr_hash = TAKE_PTR(hash);
*ret_pcr_hash_size = policy_digest->size;
r = 0;
finish:
primary = flush_context_verbose(c.esys_context, primary);
return r;
}
int tpm2_unseal(
const char *device,
uint32_t pcr_mask,
const void *blob,
size_t blob_size,
const void *known_policy_hash,
size_t known_policy_hash_size,
void **ret_secret,
size_t *ret_secret_size) {
_cleanup_(tpm2_context_destroy) struct tpm2_context c = {};
ESYS_TR primary = ESYS_TR_NONE, session = ESYS_TR_NONE, hmac_key = ESYS_TR_NONE;
_cleanup_(Esys_Freep) TPM2B_SENSITIVE_DATA* unsealed = NULL;
_cleanup_(Esys_Freep) TPM2B_DIGEST *policy_digest = NULL;
_cleanup_(erase_and_freep) char *secret = NULL;
TPM2B_PRIVATE private = {};
TPM2B_PUBLIC public = {};
size_t offset = 0;
TSS2_RC rc;
usec_t start;
int r;
assert(blob);
assert(blob_size > 0);
assert(known_policy_hash_size == 0 || known_policy_hash);
assert(ret_secret);
assert(ret_secret_size);
assert(pcr_mask < (UINT32_C(1) << TPM2_PCRS_MAX)); /* Support 24 PCR banks */
/* So here's what we do here: We connect to the TPM2 chip. As we do when sealing we generate a
* "primary" key on the TPM2 chip, with the same parameters as well as a PCR-bound policy
* session. Given we pass the same parameters, this will result in the same "primary" key, and same
* policy hash (the latter of course, only if the PCR values didn't change in between). We unmarshal
* the encrypted key we stored in the LUKS2 JSON token header and upload it into the TPM2, where it
* is decrypted if the seed and the PCR policy were right ("unsealing"). We then download the result,
* and use it to unlock the LUKS2 volume. */
start = now(CLOCK_MONOTONIC);
log_debug("Unmarshalling private part of HMAC key.");
rc = sym_Tss2_MU_TPM2B_PRIVATE_Unmarshal(blob, blob_size, &offset, &private);
if (rc != TSS2_RC_SUCCESS)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to unmarshal private key: %s", sym_Tss2_RC_Decode(rc));
log_debug("Unmarshalling public part of HMAC key.");
rc = sym_Tss2_MU_TPM2B_PUBLIC_Unmarshal(blob, blob_size, &offset, &public);
if (rc != TSS2_RC_SUCCESS)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to unmarshal public key: %s", sym_Tss2_RC_Decode(rc));
r = tpm2_init(device, &c);
if (r < 0)
return r;
r = tpm2_make_pcr_session(c.esys_context, pcr_mask, &session, &policy_digest);
if (r < 0)
goto finish;
/* If we know the policy hash to expect, and it doesn't match, we can shortcut things here, and not
* wait until the TPM2 tells us to go away. */
if (known_policy_hash_size > 0 &&
memcmp_nn(policy_digest->buffer, policy_digest->size, known_policy_hash, known_policy_hash_size) != 0)
return log_error_errno(SYNTHETIC_ERRNO(EPERM),
"Current policy digest does not match stored policy digest, cancelling TPM2 authentication attempt.");
r = tpm2_make_primary(c.esys_context, &primary);
if (r < 0)
return r;
log_debug("Loading HMAC key into TPM.");
rc = sym_Esys_Load(
c.esys_context,
primary,
ESYS_TR_PASSWORD,
ESYS_TR_NONE,
ESYS_TR_NONE,
&private,
&public,
&hmac_key);
if (rc != TSS2_RC_SUCCESS) {
r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to load HMAC key in TPM: %s", sym_Tss2_RC_Decode(rc));
goto finish;
}
log_debug("Unsealing HMAC key.");
rc = sym_Esys_Unseal(
c.esys_context,
hmac_key,
session,
ESYS_TR_NONE,
ESYS_TR_NONE,
&unsealed);
if (rc != TSS2_RC_SUCCESS) {
r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to unseal HMAC key in TPM: %s", sym_Tss2_RC_Decode(rc));
goto finish;
}
secret = memdup(unsealed->buffer, unsealed->size);
explicit_bzero_safe(unsealed->buffer, unsealed->size);
if (!secret) {
r = log_oom();
goto finish;
}
if (DEBUG_LOGGING) {
char buf[FORMAT_TIMESPAN_MAX];
log_debug("Completed TPM2 key unsealing in %s.", format_timespan(buf, sizeof(buf), now(CLOCK_MONOTONIC) - start, 1));
}
*ret_secret = TAKE_PTR(secret);
*ret_secret_size = unsealed->size;
r = 0;
finish:
primary = flush_context_verbose(c.esys_context, primary);
session = flush_context_verbose(c.esys_context, session);
hmac_key = flush_context_verbose(c.esys_context, hmac_key);
return r;
}
#endif
int tpm2_list_devices(void) {
#if HAVE_TPM2
_cleanup_(table_unrefp) Table *t = NULL;
_cleanup_(closedirp) DIR *d = NULL;
int r;
r = dlopen_tpm2();
if (r < 0)
return log_error_errno(r, "TPM2 support is not installed.");
t = table_new("path", "device", "driver");
if (!t)
return log_oom();
d = opendir("/sys/class/tpmrm");
if (!d) {
log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_ERR, errno, "Failed to open /sys/class/tpmrm: %m");
if (errno != ENOENT)
return -errno;
} else {
for (;;) {
_cleanup_free_ char *device_path = NULL, *device = NULL, *driver_path = NULL, *driver = NULL, *node = NULL;
struct dirent *de;
de = readdir_no_dot(d);
if (!de)
break;
device_path = path_join("/sys/class/tpmrm", de->d_name, "device");
if (!device_path)
return log_oom();
r = readlink_malloc(device_path, &device);
if (r < 0)
log_debug_errno(r, "Failed to read device symlink %s, ignoring: %m", device_path);
else {
driver_path = path_join(device_path, "driver");
if (!driver_path)
return log_oom();
r = readlink_malloc(driver_path, &driver);
if (r < 0)
log_debug_errno(r, "Failed to read driver symlink %s, ignoring: %m", driver_path);
}
node = path_join("/dev", de->d_name);
if (!node)
return log_oom();
r = table_add_many(
t,
TABLE_PATH, node,
TABLE_STRING, device ? last_path_component(device) : NULL,
TABLE_STRING, driver ? last_path_component(driver) : NULL);
if (r < 0)
return table_log_add_error(r);
}
}
if (table_get_rows(t) <= 1) {
log_info("No suitable TPM2 devices found.");
return 0;
}
r = table_print(t, stdout);
if (r < 0)
return log_error_errno(r, "Failed to show device table: %m");
return 0;
#else
return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
"TPM2 not supported on this build.");
#endif
}
int tpm2_find_device_auto(
int log_level, /* log level when no device is found */
char **ret) {
#if HAVE_TPM2
_cleanup_(closedirp) DIR *d = NULL;
int r;
r = dlopen_tpm2();
if (r < 0)
return log_error_errno(r, "TPM2 support is not installed.");
d = opendir("/sys/class/tpmrm");
if (!d) {
log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_ERR, errno,
"Failed to open /sys/class/tpmrm: %m");
if (errno != ENOENT)
return -errno;
} else {
_cleanup_free_ char *node = NULL;
for (;;) {
struct dirent *de;
de = readdir_no_dot(d);
if (!de)
break;
if (node)
return log_error_errno(SYNTHETIC_ERRNO(ENOTUNIQ),
"More than one TPM2 (tpmrm) device found.");
node = path_join("/dev", de->d_name);
if (!node)
return log_oom();
}
if (node) {
*ret = TAKE_PTR(node);
return 0;
}
}
return log_full_errno(log_level, SYNTHETIC_ERRNO(ENODEV), "No TPM2 (tpmrm) device found.");
#else
return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
"TPM2 not supported on this build.");
#endif
}
int tpm2_parse_pcrs(const char *s, uint32_t *ret) {
const char *p = s;
uint32_t mask = 0;
int r;
/* Parses a comma-separated list of PCR indexes */
for (;;) {
_cleanup_free_ char *pcr = NULL;
unsigned n;
r = extract_first_word(&p, &pcr, ",", EXTRACT_DONT_COALESCE_SEPARATORS);
if (r == 0)
break;
if (r < 0)
return log_error_errno(r, "Failed to parse PCR list: %s", s);
r = safe_atou(pcr, &n);
if (r < 0)
return log_error_errno(r, "Failed to parse PCR number: %s", pcr);
if (n >= TPM2_PCRS_MAX)
return log_error_errno(SYNTHETIC_ERRNO(ERANGE),
"PCR number out of range (valid range 0…23): %u", n);
mask |= UINT32_C(1) << n;
}
*ret = mask;
return 0;
}
int tpm2_make_luks2_json(
int keyslot,
uint32_t pcr_mask,
const void *blob,
size_t blob_size,
const void *policy_hash,
size_t policy_hash_size,
JsonVariant **ret) {
_cleanup_(json_variant_unrefp) JsonVariant *v = NULL, *a = NULL;
_cleanup_free_ char *keyslot_as_string = NULL;
JsonVariant* pcr_array[TPM2_PCRS_MAX];
unsigned n_pcrs = 0;
int r;
assert(blob || blob_size == 0);
assert(policy_hash || policy_hash_size == 0);
if (asprintf(&keyslot_as_string, "%i", keyslot) < 0)
return -ENOMEM;
for (unsigned i = 0; i < ELEMENTSOF(pcr_array); i++) {
if ((pcr_mask & (UINT32_C(1) << i)) == 0)
continue;
r = json_variant_new_integer(pcr_array + n_pcrs, i);
if (r < 0) {
json_variant_unref_many(pcr_array, n_pcrs);
return -ENOMEM;
}
n_pcrs++;
}
r = json_variant_new_array(&a, pcr_array, n_pcrs);
json_variant_unref_many(pcr_array, n_pcrs);
if (r < 0)
return -ENOMEM;
r = json_build(&v,
JSON_BUILD_OBJECT(
JSON_BUILD_PAIR("type", JSON_BUILD_STRING("systemd-tpm2")),
JSON_BUILD_PAIR("keyslots", JSON_BUILD_ARRAY(JSON_BUILD_STRING(keyslot_as_string))),
JSON_BUILD_PAIR("tpm2-blob", JSON_BUILD_BASE64(blob, blob_size)),
JSON_BUILD_PAIR("tpm2-pcrs", JSON_BUILD_VARIANT(a)),
JSON_BUILD_PAIR("tpm2-policy-hash", JSON_BUILD_HEX(policy_hash, policy_hash_size))));
if (r < 0)
return r;
if (ret)
*ret = TAKE_PTR(v);
return keyslot;
}

51
src/shared/tpm2-util.h Normal file
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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once
#include "json.h"
#include "macro.h"
#if HAVE_TPM2
#include <tss2/tss2_esys.h>
#include <tss2/tss2_mu.h>
#include <tss2/tss2_rc.h>
extern TSS2_RC (*sym_Esys_Create)(ESYS_CONTEXT *esysContext, ESYS_TR parentHandle, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, const TPM2B_SENSITIVE_CREATE *inSensitive, const TPM2B_PUBLIC *inPublic, const TPM2B_DATA *outsideInfo, const TPML_PCR_SELECTION *creationPCR, TPM2B_PRIVATE **outPrivate, TPM2B_PUBLIC **outPublic, TPM2B_CREATION_DATA **creationData, TPM2B_DIGEST **creationHash, TPMT_TK_CREATION **creationTicket);
extern TSS2_RC (*sym_Esys_CreatePrimary)(ESYS_CONTEXT *esysContext, ESYS_TR primaryHandle, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, const TPM2B_SENSITIVE_CREATE *inSensitive, const TPM2B_PUBLIC *inPublic, const TPM2B_DATA *outsideInfo, const TPML_PCR_SELECTION *creationPCR, ESYS_TR *objectHandle, TPM2B_PUBLIC **outPublic, TPM2B_CREATION_DATA **creationData, TPM2B_DIGEST **creationHash, TPMT_TK_CREATION **creationTicket);
extern void (*sym_Esys_Finalize)(ESYS_CONTEXT **context);
extern TSS2_RC (*sym_Esys_FlushContext)(ESYS_CONTEXT *esysContext, ESYS_TR flushHandle);
extern void (*sym_Esys_Free)(void *ptr);
extern TSS2_RC (*sym_Esys_GetRandom)(ESYS_CONTEXT *esysContext, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, UINT16 bytesRequested, TPM2B_DIGEST **randomBytes);
extern TSS2_RC (*sym_Esys_Initialize)(ESYS_CONTEXT **esys_context, TSS2_TCTI_CONTEXT *tcti, TSS2_ABI_VERSION *abiVersion);
extern TSS2_RC (*sym_Esys_Load)(ESYS_CONTEXT *esysContext, ESYS_TR parentHandle, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, const TPM2B_PRIVATE *inPrivate, const TPM2B_PUBLIC *inPublic, ESYS_TR *objectHandle);
extern TSS2_RC (*sym_Esys_PolicyGetDigest)(ESYS_CONTEXT *esysContext, ESYS_TR policySession, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, TPM2B_DIGEST **policyDigest);
extern TSS2_RC (*sym_Esys_PolicyPCR)(ESYS_CONTEXT *esysContext, ESYS_TR policySession, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, const TPM2B_DIGEST *pcrDigest, const TPML_PCR_SELECTION *pcrs);
extern TSS2_RC (*sym_Esys_StartAuthSession)(ESYS_CONTEXT *esysContext, ESYS_TR tpmKey, ESYS_TR bind, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, const TPM2B_NONCE *nonceCaller, TPM2_SE sessionType, const TPMT_SYM_DEF *symmetric, TPMI_ALG_HASH authHash, ESYS_TR *sessionHandle);
extern TSS2_RC (*sym_Esys_Startup)(ESYS_CONTEXT *esysContext, TPM2_SU startupType);
extern TSS2_RC (*sym_Esys_Unseal)(ESYS_CONTEXT *esysContext, ESYS_TR itemHandle, ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3, TPM2B_SENSITIVE_DATA **outData);
extern const char* (*sym_Tss2_RC_Decode)(TSS2_RC rc);
extern TSS2_RC (*sym_Tss2_MU_TPM2B_PRIVATE_Marshal)(TPM2B_PRIVATE const *src, uint8_t buffer[], size_t buffer_size, size_t *offset);
extern TSS2_RC (*sym_Tss2_MU_TPM2B_PRIVATE_Unmarshal)(uint8_t const buffer[], size_t buffer_size, size_t *offset, TPM2B_PRIVATE *dest);
extern TSS2_RC (*sym_Tss2_MU_TPM2B_PUBLIC_Marshal)(TPM2B_PUBLIC const *src, uint8_t buffer[], size_t buffer_size, size_t *offset);
extern TSS2_RC (*sym_Tss2_MU_TPM2B_PUBLIC_Unmarshal)(uint8_t const buffer[], size_t buffer_size, size_t *offset, TPM2B_PUBLIC *dest);
int dlopen_tpm2(void);
int tpm2_seal(const char *device, uint32_t pcr_mask, void **ret_secret, size_t *ret_secret_size, void **ret_blob, size_t *ret_blob_size, void **ret_pcr_hash, size_t *ret_pcr_hash_size);
int tpm2_unseal(const char *device, uint32_t pcr_mask, const void *blob, size_t blob_size, const void *pcr_hash, size_t pcr_hash_size, void **ret_secret, size_t *ret_secret_size);
#endif
int tpm2_list_devices(void);
int tpm2_find_device_auto(int log_level, char **ret);
int tpm2_parse_pcrs(const char *s, uint32_t *ret);
int tpm2_make_luks2_json(int keyslot, uint32_t pcr_mask, const void *blob, size_t blob_size, const void *policy_hash, size_t policy_hash_size, JsonVariant **ret);
#define TPM2_PCRS_MAX 24
/* Default to PCR 7 only */
#define TPM2_PCR_MASK_DEFAULT (UINT32_C(1) << 7)