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tor/src/or/routerkeys.c

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/* Copyright (c) 2014-2017, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file routerkeys.c
*
* \brief Functions and structures to handle generating and maintaining the
* set of keypairs necessary to be an OR.
*
* The keys handled here now are the Ed25519 keys that Tor relays use to sign
* descriptors, authenticate themselves on links, and identify one another
* uniquely. Other keys are maintained in router.c and rendservice.c.
*
* (TODO: The keys in router.c should go here too.)
*/
#include "or.h"
#include "config.h"
#include "crypto_util.h"
#include "router.h"
#include "crypto_pwbox.h"
#include "routerkeys.h"
#include "torcert.h"
#define ENC_KEY_HEADER "Boxed Ed25519 key"
#define ENC_KEY_TAG "master"
/* DOCDOC */
static ssize_t
do_getpass(const char *prompt, char *buf, size_t buflen,
int twice, const or_options_t *options)
{
if (options->keygen_force_passphrase == FORCE_PASSPHRASE_OFF) {
tor_assert(buflen);
buf[0] = 0;
return 0;
}
char *prompt2 = NULL;
char *buf2 = NULL;
int fd = -1;
ssize_t length = -1;
if (options->use_keygen_passphrase_fd) {
twice = 0;
fd = options->keygen_passphrase_fd;
length = read_all(fd, buf, buflen-1, 0);
if (length >= 0)
buf[length] = 0;
goto done_reading;
}
if (twice) {
const char msg[] = "One more time:";
size_t p2len = strlen(prompt) + 1;
if (p2len < sizeof(msg))
p2len = sizeof(msg);
prompt2 = tor_malloc(p2len);
memset(prompt2, ' ', p2len);
memcpy(prompt2 + p2len - sizeof(msg), msg, sizeof(msg));
buf2 = tor_malloc_zero(buflen);
}
while (1) {
length = tor_getpass(prompt, buf, buflen);
if (length < 0)
goto done_reading;
if (! twice)
break;
ssize_t length2 = tor_getpass(prompt2, buf2, buflen);
if (length != length2 || tor_memneq(buf, buf2, length)) {
fprintf(stderr, "That didn't match.\n");
} else {
break;
}
}
done_reading:
if (twice) {
tor_free(prompt2);
memwipe(buf2, 0, buflen);
tor_free(buf2);
}
if (options->keygen_force_passphrase == FORCE_PASSPHRASE_ON && length == 0)
return -1;
return length;
}
/* DOCDOC */
int
read_encrypted_secret_key(ed25519_secret_key_t *out,
const char *fname)
{
int r = -1;
uint8_t *secret = NULL;
size_t secret_len = 0;
char pwbuf[256];
uint8_t encrypted_key[256];
char *tag = NULL;
int saved_errno = 0;
ssize_t encrypted_len = crypto_read_tagged_contents_from_file(fname,
ENC_KEY_HEADER,
&tag,
encrypted_key,
sizeof(encrypted_key));
if (encrypted_len < 0) {
saved_errno = errno;
log_info(LD_OR, "%s is missing", fname);
r = 0;
goto done;
}
if (strcmp(tag, ENC_KEY_TAG)) {
saved_errno = EINVAL;
goto done;
}
while (1) {
ssize_t pwlen =
do_getpass("Enter passphrase for master key:", pwbuf, sizeof(pwbuf), 0,
get_options());
if (pwlen < 0) {
saved_errno = EINVAL;
goto done;
}
const int r_unbox = crypto_unpwbox(&secret, &secret_len,
encrypted_key, encrypted_len,
pwbuf, pwlen);
if (r_unbox == UNPWBOX_CORRUPTED) {
log_err(LD_OR, "%s is corrupted.", fname);
saved_errno = EINVAL;
goto done;
} else if (r_unbox == UNPWBOX_OKAY) {
break;
}
/* Otherwise, passphrase is bad, so try again till user does ctrl-c or gets
* it right. */
}
if (secret_len != ED25519_SECKEY_LEN) {
log_err(LD_OR, "%s is corrupted.", fname);
saved_errno = EINVAL;
goto done;
}
memcpy(out->seckey, secret, ED25519_SECKEY_LEN);
r = 1;
done:
memwipe(encrypted_key, 0, sizeof(encrypted_key));
memwipe(pwbuf, 0, sizeof(pwbuf));
tor_free(tag);
if (secret) {
memwipe(secret, 0, secret_len);
tor_free(secret);
}
if (saved_errno)
errno = saved_errno;
return r;
}
/* DOCDOC */
int
write_encrypted_secret_key(const ed25519_secret_key_t *key,
const char *fname)
{
int r = -1;
char pwbuf0[256];
uint8_t *encrypted_key = NULL;
size_t encrypted_len = 0;
if (do_getpass("Enter new passphrase:", pwbuf0, sizeof(pwbuf0), 1,
get_options()) < 0) {
log_warn(LD_OR, "NO/failed passphrase");
return -1;
}
if (strlen(pwbuf0) == 0) {
if (get_options()->keygen_force_passphrase == FORCE_PASSPHRASE_ON)
return -1;
else
return 0;
}
if (crypto_pwbox(&encrypted_key, &encrypted_len,
key->seckey, sizeof(key->seckey),
pwbuf0, strlen(pwbuf0), 0) < 0) {
log_warn(LD_OR, "crypto_pwbox failed!?");
goto done;
}
if (crypto_write_tagged_contents_to_file(fname,
ENC_KEY_HEADER,
ENC_KEY_TAG,
encrypted_key, encrypted_len) < 0)
goto done;
r = 1;
done:
if (encrypted_key) {
memwipe(encrypted_key, 0, encrypted_len);
tor_free(encrypted_key);
}
memwipe(pwbuf0, 0, sizeof(pwbuf0));
return r;
}
/* DOCDOC */
static int
write_secret_key(const ed25519_secret_key_t *key, int encrypted,
const char *fname,
const char *fname_tag,
const char *encrypted_fname)
{
if (encrypted) {
int r = write_encrypted_secret_key(key, encrypted_fname);
if (r == 1) {
/* Success! */
/* Try to unlink the unencrypted key, if any existed before */
if (strcmp(fname, encrypted_fname))
unlink(fname);
return r;
} else if (r != 0) {
/* Unrecoverable failure! */
return r;
}
fprintf(stderr, "Not encrypting the secret key.\n");
}
return ed25519_seckey_write_to_file(key, fname, fname_tag);
}
/**
* Read an ed25519 key and associated certificates from files beginning with
* <b>fname</b>, with certificate type <b>cert_type</b>. On failure, return
* NULL; on success return the keypair.
*
* If INIT_ED_KEY_CREATE is set in <b>flags</b>, then create the key (and
* certificate if requested) if it doesn't exist, and save it to disk.
*
* If INIT_ED_KEY_NEEDCERT is set in <b>flags</b>, load/create a certificate
* too and store it in *<b>cert_out</b>. Fail if the cert can't be
* found/created. To create a certificate, <b>signing_key</b> must be set to
* the key that should sign it; <b>now</b> to the current time, and
* <b>lifetime</b> to the lifetime of the key.
*
* If INIT_ED_KEY_REPLACE is set in <b>flags</b>, then create and save new key
* whether we can read the old one or not.
*
* If INIT_ED_KEY_EXTRA_STRONG is set in <b>flags</b>, set the extra_strong
* flag when creating the secret key.
*
* If INIT_ED_KEY_INCLUDE_SIGNING_KEY_IN_CERT is set in <b>flags</b>, and
* we create a new certificate, create it with the signing key embedded.
*
* If INIT_ED_KEY_SPLIT is set in <b>flags</b>, and we create a new key,
* store the public key in a separate file from the secret key.
*
* If INIT_ED_KEY_MISSING_SECRET_OK is set in <b>flags</b>, and we find a
* public key file but no secret key file, return successfully anyway.
*
* If INIT_ED_KEY_OMIT_SECRET is set in <b>flags</b>, do not try to load a
* secret key unless no public key is found. Do not return a secret key. (but
* create and save one if needed).
*
* If INIT_ED_KEY_NO_LOAD_SECRET is set in <b>flags</b>, don't try to load
* a secret key, no matter what.
*
* If INIT_ED_KEY_TRY_ENCRYPTED is set, we look for an encrypted secret key
* and consider encrypting any new secret key.
*
* If INIT_ED_KEY_NO_REPAIR is set, and there is any issue loading the keys
* from disk _other than their absence_ (full or partial), we do not try to
* replace them.
*
* If INIT_ED_KEY_SUGGEST_KEYGEN is set, have log messages about failures
* refer to the --keygen option.
*
* If INIT_ED_KEY_EXPLICIT_FNAME is set, use the provided file name for the
* secret key file, encrypted or not.
*/
ed25519_keypair_t *
ed_key_init_from_file(const char *fname, uint32_t flags,
int severity,
const ed25519_keypair_t *signing_key,
time_t now,
time_t lifetime,
uint8_t cert_type,
struct tor_cert_st **cert_out)
{
char *secret_fname = NULL;
char *encrypted_secret_fname = NULL;
char *public_fname = NULL;
char *cert_fname = NULL;
const char *loaded_secret_fname = NULL;
int created_pk = 0, created_sk = 0, created_cert = 0;
const int try_to_load = ! (flags & INIT_ED_KEY_REPLACE);
const int encrypt_key = !! (flags & INIT_ED_KEY_TRY_ENCRYPTED);
const int norepair = !! (flags & INIT_ED_KEY_NO_REPAIR);
const int split = !! (flags & INIT_ED_KEY_SPLIT);
const int omit_secret = !! (flags & INIT_ED_KEY_OMIT_SECRET);
const int offline_secret = !! (flags & INIT_ED_KEY_OFFLINE_SECRET);
const int explicit_fname = !! (flags & INIT_ED_KEY_EXPLICIT_FNAME);
/* we don't support setting both of these flags at once. */
tor_assert((flags & (INIT_ED_KEY_NO_REPAIR|INIT_ED_KEY_NEEDCERT)) !=
(INIT_ED_KEY_NO_REPAIR|INIT_ED_KEY_NEEDCERT));
char tag[8];
tor_snprintf(tag, sizeof(tag), "type%d", (int)cert_type);
tor_cert_t *cert = NULL;
char *got_tag = NULL;
ed25519_keypair_t *keypair = tor_malloc_zero(sizeof(ed25519_keypair_t));
if (explicit_fname) {
secret_fname = tor_strdup(fname);
encrypted_secret_fname = tor_strdup(fname);
} else {
tor_asprintf(&secret_fname, "%s_secret_key", fname);
tor_asprintf(&encrypted_secret_fname, "%s_secret_key_encrypted", fname);
}
tor_asprintf(&public_fname, "%s_public_key", fname);
tor_asprintf(&cert_fname, "%s_cert", fname);
/* Try to read the secret key. */
int have_secret = 0;
int load_secret = try_to_load &&
!offline_secret &&
(!omit_secret || file_status(public_fname)==FN_NOENT);
if (load_secret) {
int rv = ed25519_seckey_read_from_file(&keypair->seckey,
&got_tag, secret_fname);
if (rv == 0) {
have_secret = 1;
loaded_secret_fname = secret_fname;
tor_assert(got_tag);
} else {
if (errno != ENOENT && norepair) {
tor_log(severity, LD_OR, "Unable to read %s: %s", secret_fname,
strerror(errno));
goto err;
}
}
}
/* Should we try for an encrypted key? */
int have_encrypted_secret_file = 0;
if (!have_secret && try_to_load && encrypt_key) {
int r = read_encrypted_secret_key(&keypair->seckey,
encrypted_secret_fname);
if (r > 0) {
have_secret = 1;
have_encrypted_secret_file = 1;
tor_free(got_tag); /* convince coverity we aren't leaking */
got_tag = tor_strdup(tag);
loaded_secret_fname = encrypted_secret_fname;
} else if (errno != ENOENT && norepair) {
tor_log(severity, LD_OR, "Unable to read %s: %s",
encrypted_secret_fname, strerror(errno));
goto err;
}
} else {
if (try_to_load) {
/* Check if it's there anyway, so we don't replace it. */
if (file_status(encrypted_secret_fname) != FN_NOENT)
have_encrypted_secret_file = 1;
}
}
if (have_secret) {
if (strcmp(got_tag, tag)) {
tor_log(severity, LD_OR, "%s has wrong tag", loaded_secret_fname);
goto err;
}
/* Derive the public key */
if (ed25519_public_key_generate(&keypair->pubkey, &keypair->seckey)<0) {
tor_log(severity, LD_OR, "%s can't produce a public key",
loaded_secret_fname);
goto err;
}
}
/* If we do split keys here, try to read the pubkey. */
int found_public = 0;
if (try_to_load && (!have_secret || split)) {
ed25519_public_key_t pubkey_tmp;
tor_free(got_tag);
found_public = ed25519_pubkey_read_from_file(&pubkey_tmp,
&got_tag, public_fname) == 0;
if (!found_public && errno != ENOENT && norepair) {
tor_log(severity, LD_OR, "Unable to read %s: %s", public_fname,
strerror(errno));
goto err;
}
if (found_public && strcmp(got_tag, tag)) {
tor_log(severity, LD_OR, "%s has wrong tag", public_fname);
goto err;
}
if (found_public) {
if (have_secret) {
/* If we have a secret key and we're reloading the public key,
* the key must match! */
if (! ed25519_pubkey_eq(&keypair->pubkey, &pubkey_tmp)) {
tor_log(severity, LD_OR, "%s does not match %s! If you are trying "
"to restore from backup, make sure you didn't mix up the "
"key files. If you are absolutely sure that %s is the right "
"key for this relay, delete %s or move it out of the way.",
public_fname, loaded_secret_fname,
loaded_secret_fname, public_fname);
goto err;
}
} else {
/* We only have the public key; better use that. */
tor_assert(split);
memcpy(&keypair->pubkey, &pubkey_tmp, sizeof(pubkey_tmp));
}
} else {
/* We have no public key file, but we do have a secret key, make the
* public key file! */
if (have_secret) {
if (ed25519_pubkey_write_to_file(&keypair->pubkey, public_fname, tag)
< 0) {
tor_log(severity, LD_OR, "Couldn't repair %s", public_fname);
goto err;
} else {
tor_log(LOG_NOTICE, LD_OR,
"Found secret key but not %s. Regenerating.",
public_fname);
}
}
}
}
/* If the secret key is absent and it's not allowed to be, fail. */
if (!have_secret && found_public &&
!(flags & INIT_ED_KEY_MISSING_SECRET_OK)) {
if (have_encrypted_secret_file) {
tor_log(severity, LD_OR, "We needed to load a secret key from %s, "
"but it was encrypted. Try 'tor --keygen' instead, so you "
"can enter the passphrase.",
secret_fname);
} else if (offline_secret) {
tor_log(severity, LD_OR, "We wanted to load a secret key from %s, "
"but you're keeping it offline. (OfflineMasterKey is set.)",
secret_fname);
} else {
tor_log(severity, LD_OR, "We needed to load a secret key from %s, "
"but couldn't find it. %s", secret_fname,
(flags & INIT_ED_KEY_SUGGEST_KEYGEN) ?
"If you're keeping your master secret key offline, you will "
"need to run 'tor --keygen' to generate new signing keys." :
"Did you forget to copy it over when you copied the rest of the "
"signing key material?");
}
goto err;
}
/* If it's absent, and we're not supposed to make a new keypair, fail. */
if (!have_secret && !found_public && !(flags & INIT_ED_KEY_CREATE)) {
if (split) {
tor_log(severity, LD_OR, "No key found in %s or %s.",
secret_fname, public_fname);
} else {
tor_log(severity, LD_OR, "No key found in %s.", secret_fname);
}
goto err;
}
/* If the secret key is absent, but the encrypted key would be present,
* that's an error */
if (!have_secret && !found_public && have_encrypted_secret_file) {
tor_assert(!encrypt_key);
tor_log(severity, LD_OR, "Found an encrypted secret key, "
"but not public key file %s!", public_fname);
goto err;
}
/* if it's absent, make a new keypair... */
if (!have_secret && !found_public) {
tor_free(keypair);
keypair = ed_key_new(signing_key, flags, now, lifetime,
cert_type, &cert);
if (!keypair) {
tor_log(severity, LD_OR, "Couldn't create keypair");
goto err;
}
created_pk = created_sk = created_cert = 1;
}
/* Write it to disk if we're supposed to do with a new passphrase, or if
* we just created it. */
if (created_sk || (have_secret && get_options()->change_key_passphrase)) {
if (write_secret_key(&keypair->seckey,
encrypt_key,
secret_fname, tag, encrypted_secret_fname) < 0
||
(split &&
ed25519_pubkey_write_to_file(&keypair->pubkey, public_fname, tag) < 0)
||
(cert &&
crypto_write_tagged_contents_to_file(cert_fname, "ed25519v1-cert",
tag, cert->encoded, cert->encoded_len) < 0)) {
tor_log(severity, LD_OR, "Couldn't write keys or cert to file.");
goto err;
}
goto done;
}
/* If we're not supposed to get a cert, we're done. */
if (! (flags & INIT_ED_KEY_NEEDCERT))
goto done;
/* Read a cert. */
tor_free(got_tag);
uint8_t certbuf[256];
ssize_t cert_body_len = crypto_read_tagged_contents_from_file(
cert_fname, "ed25519v1-cert",
&got_tag, certbuf, sizeof(certbuf));
if (cert_body_len >= 0 && !strcmp(got_tag, tag))
cert = tor_cert_parse(certbuf, cert_body_len);
/* If we got it, check it to the extent we can. */
int bad_cert = 0;
if (! cert) {
tor_log(severity, LD_OR, "Cert was unparseable");
bad_cert = 1;
} else if (!tor_memeq(cert->signed_key.pubkey, keypair->pubkey.pubkey,
ED25519_PUBKEY_LEN)) {
tor_log(severity, LD_OR, "Cert was for wrong key");
bad_cert = 1;
} else if (signing_key &&
tor_cert_checksig(cert, &signing_key->pubkey, now) < 0) {
tor_log(severity, LD_OR, "Can't check certificate: %s",
tor_cert_describe_signature_status(cert));
bad_cert = 1;
} else if (cert->cert_expired) {
tor_log(severity, LD_OR, "Certificate is expired");
bad_cert = 1;
} else if (signing_key && cert->signing_key_included &&
! ed25519_pubkey_eq(&signing_key->pubkey, &cert->signing_key)) {
tor_log(severity, LD_OR, "Certificate signed by unexpectd key!");
bad_cert = 1;
}
if (bad_cert) {
tor_cert_free(cert);
cert = NULL;
}
/* If we got a cert, we're done. */
if (cert)
goto done;
/* If we didn't get a cert, and we're not supposed to make one, fail. */
if (!signing_key || !(flags & INIT_ED_KEY_CREATE)) {
tor_log(severity, LD_OR, "Without signing key, can't create certificate");
goto err;
}
/* We have keys but not a certificate, so make one. */
uint32_t cert_flags = 0;
if (flags & INIT_ED_KEY_INCLUDE_SIGNING_KEY_IN_CERT)
cert_flags |= CERT_FLAG_INCLUDE_SIGNING_KEY;
cert = tor_cert_create(signing_key, cert_type,
&keypair->pubkey,
now, lifetime,
cert_flags);
if (! cert) {
tor_log(severity, LD_OR, "Couldn't create certificate");
goto err;
}
/* Write it to disk. */
created_cert = 1;
if (crypto_write_tagged_contents_to_file(cert_fname, "ed25519v1-cert",
tag, cert->encoded, cert->encoded_len) < 0) {
tor_log(severity, LD_OR, "Couldn't write cert to disk.");
goto err;
}
done:
if (cert_out)
*cert_out = cert;
else
tor_cert_free(cert);
goto cleanup;
err:
if (keypair)
memwipe(keypair, 0, sizeof(*keypair));
tor_free(keypair);
tor_cert_free(cert);
if (cert_out)
*cert_out = NULL;
if (created_sk)
unlink(secret_fname);
if (created_pk)
unlink(public_fname);
if (created_cert)
unlink(cert_fname);
cleanup:
tor_free(encrypted_secret_fname);
tor_free(secret_fname);
tor_free(public_fname);
tor_free(cert_fname);
tor_free(got_tag);
return keypair;
}
/**
* Create a new signing key and (optionally) certficiate; do not read or write
* from disk. See ed_key_init_from_file() for more information.
*/
ed25519_keypair_t *
ed_key_new(const ed25519_keypair_t *signing_key,
uint32_t flags,
time_t now,
time_t lifetime,
uint8_t cert_type,
struct tor_cert_st **cert_out)
{
if (cert_out)
*cert_out = NULL;
const int extra_strong = !! (flags & INIT_ED_KEY_EXTRA_STRONG);
ed25519_keypair_t *keypair = tor_malloc_zero(sizeof(ed25519_keypair_t));
if (ed25519_keypair_generate(keypair, extra_strong) < 0)
goto err;
if (! (flags & INIT_ED_KEY_NEEDCERT))
return keypair;
tor_assert(signing_key);
tor_assert(cert_out);
uint32_t cert_flags = 0;
if (flags & INIT_ED_KEY_INCLUDE_SIGNING_KEY_IN_CERT)
cert_flags |= CERT_FLAG_INCLUDE_SIGNING_KEY;
tor_cert_t *cert = tor_cert_create(signing_key, cert_type,
&keypair->pubkey,
now, lifetime,
cert_flags);
if (! cert)
goto err;
*cert_out = cert;
return keypair;
err:
tor_free(keypair);
return NULL;
}
static ed25519_keypair_t *master_identity_key = NULL;
static ed25519_keypair_t *master_signing_key = NULL;
static ed25519_keypair_t *current_auth_key = NULL;
static tor_cert_t *signing_key_cert = NULL;
static tor_cert_t *link_cert_cert = NULL;
static tor_cert_t *auth_key_cert = NULL;
static uint8_t *rsa_ed_crosscert = NULL;
static size_t rsa_ed_crosscert_len = 0;
static time_t rsa_ed_crosscert_expiration = 0;
/**
* Running as a server: load, reload, or refresh our ed25519 keys and
* certificates, creating and saving new ones as needed.
*
* Return -1 on failure; 0 on success if the signing key was not replaced;
* and 1 on success if the signing key was replaced.
*/
int
load_ed_keys(const or_options_t *options, time_t now)
{
ed25519_keypair_t *id = NULL;
ed25519_keypair_t *sign = NULL;
ed25519_keypair_t *auth = NULL;
const ed25519_keypair_t *sign_signing_key_with_id = NULL;
const ed25519_keypair_t *use_signing = NULL;
const tor_cert_t *check_signing_cert = NULL;
tor_cert_t *sign_cert = NULL;
tor_cert_t *auth_cert = NULL;
int signing_key_changed = 0;
// It is later than 1972, since otherwise there would be no C compilers.
// (Try to diagnose #22466.)
tor_assert_nonfatal(now >= 2 * 365 * 86400);
#define FAIL(msg) do { \
log_warn(LD_OR, (msg)); \
goto err; \
} while (0)
#define SET_KEY(key, newval) do { \
if ((key) != (newval)) \
ed25519_keypair_free(key); \
key = (newval); \
} while (0)
#define SET_CERT(cert, newval) do { \
if ((cert) != (newval)) \
tor_cert_free(cert); \
cert = (newval); \
} while (0)
#define HAPPENS_SOON(when, interval) \
((when) < now + (interval))
#define EXPIRES_SOON(cert, interval) \
(!(cert) || HAPPENS_SOON((cert)->valid_until, (interval)))
/* XXXX support encrypted identity keys fully */
/* First try to get the signing key to see how it is. */
{
char *fname =
options_get_keydir_fname(options, "ed25519_signing");
sign = ed_key_init_from_file(
fname,
INIT_ED_KEY_NEEDCERT|
INIT_ED_KEY_INCLUDE_SIGNING_KEY_IN_CERT,
LOG_INFO,
NULL, 0, 0, CERT_TYPE_ID_SIGNING, &sign_cert);
tor_free(fname);
check_signing_cert = sign_cert;
use_signing = sign;
}
if (use_signing) {
/* We loaded a signing key with its certificate. */
if (! master_signing_key) {
/* We didn't know one before! */
signing_key_changed = 1;
} else if (! ed25519_pubkey_eq(&use_signing->pubkey,
&master_signing_key->pubkey) ||
! tor_memeq(use_signing->seckey.seckey,
master_signing_key->seckey.seckey,
ED25519_SECKEY_LEN)) {
/* We loaded a different signing key than the one we knew before. */
signing_key_changed = 1;
}
}
if (!use_signing && master_signing_key) {
/* We couldn't load a signing key, but we already had one loaded */
check_signing_cert = signing_key_cert;
use_signing = master_signing_key;
}
const int offline_master =
options->OfflineMasterKey && options->command != CMD_KEYGEN;
const int need_new_signing_key =
NULL == use_signing ||
EXPIRES_SOON(check_signing_cert, 0) ||
(options->command == CMD_KEYGEN && ! options->change_key_passphrase);
const int want_new_signing_key =
need_new_signing_key ||
EXPIRES_SOON(check_signing_cert, options->TestingSigningKeySlop);
/* We can only create a master key if we haven't been told that the
* master key will always be offline. Also, if we have a signing key,
* then we shouldn't make a new master ID key. */
const int can_make_master_id_key = !offline_master &&
NULL == use_signing;
if (need_new_signing_key) {
log_notice(LD_OR, "It looks like I need to generate and sign a new "
"medium-term signing key, because %s. To do that, I "
"need to load%s the permanent master identity key. "
"If the master identity key was not moved or encrypted "
"with a passphrase, this will be done automatically and "
"no further action is required. Otherwise, provide the "
"necessary data using 'tor --keygen' to do it manually.",
(NULL == use_signing) ? "I don't have one" :
EXPIRES_SOON(check_signing_cert, 0) ? "the one I have is expired" :
"you asked me to make one with --keygen",
can_make_master_id_key ? " (or create)" : "");
} else if (want_new_signing_key && !offline_master) {
log_notice(LD_OR, "It looks like I should try to generate and sign a "
"new medium-term signing key, because the one I have is "
"going to expire soon. To do that, I'm going to have to "
"try to load the permanent master identity key. "
"If the master identity key was not moved or encrypted "
"with a passphrase, this will be done automatically and "
"no further action is required. Otherwise, provide the "
"necessary data using 'tor --keygen' to do it manually.");
} else if (want_new_signing_key) {
log_notice(LD_OR, "It looks like I should try to generate and sign a "
"new medium-term signing key, because the one I have is "
"going to expire soon. But OfflineMasterKey is set, so I "
"won't try to load a permanent master identity key. You "
"will need to use 'tor --keygen' to make a new signing "
"key and certificate.");
}
{
uint32_t flags =
(INIT_ED_KEY_SPLIT|
INIT_ED_KEY_EXTRA_STRONG|INIT_ED_KEY_NO_REPAIR);
if (can_make_master_id_key)
flags |= INIT_ED_KEY_CREATE;
if (! need_new_signing_key)
flags |= INIT_ED_KEY_MISSING_SECRET_OK;
if (! want_new_signing_key || offline_master)
flags |= INIT_ED_KEY_OMIT_SECRET;
if (offline_master)
flags |= INIT_ED_KEY_OFFLINE_SECRET;
if (options->command == CMD_KEYGEN)
flags |= INIT_ED_KEY_TRY_ENCRYPTED;
/* Check/Create the key directory */
if (create_keys_directory(options) < 0)
return -1;
char *fname;
if (options->master_key_fname) {
fname = tor_strdup(options->master_key_fname);
flags |= INIT_ED_KEY_EXPLICIT_FNAME;
} else {
fname = options_get_keydir_fname(options, "ed25519_master_id");
}
id = ed_key_init_from_file(
fname,
flags,
LOG_WARN, NULL, 0, 0, 0, NULL);
tor_free(fname);
if (!id) {
if (need_new_signing_key) {
if (offline_master)
FAIL("Can't load master identity key; OfflineMasterKey is set.");
else
FAIL("Missing identity key");
} else {
log_warn(LD_OR, "Master public key was absent; inferring from "
"public key in signing certificate and saving to disk.");
tor_assert(check_signing_cert);
id = tor_malloc_zero(sizeof(*id));
memcpy(&id->pubkey, &check_signing_cert->signing_key,
sizeof(ed25519_public_key_t));
fname = options_get_keydir_fname(options,
"ed25519_master_id_public_key");
if (ed25519_pubkey_write_to_file(&id->pubkey, fname, "type0") < 0) {
log_warn(LD_OR, "Error while attempting to write master public key "
"to disk");
tor_free(fname);
goto err;
}
tor_free(fname);
}
}
if (tor_mem_is_zero((char*)id->seckey.seckey, sizeof(id->seckey)))
sign_signing_key_with_id = NULL;
else
sign_signing_key_with_id = id;
}
if (master_identity_key &&
!ed25519_pubkey_eq(&id->pubkey, &master_identity_key->pubkey)) {
FAIL("Identity key on disk does not match key we loaded earlier!");
}
if (need_new_signing_key && NULL == sign_signing_key_with_id)
FAIL("Can't load master key make a new signing key.");
if (sign_cert) {
if (! sign_cert->signing_key_included)
FAIL("Loaded a signing cert with no key included!");
if (! ed25519_pubkey_eq(&sign_cert->signing_key, &id->pubkey))
FAIL("The signing cert we have was not signed with the master key "
"we loaded!");
if (tor_cert_checksig(sign_cert, &id->pubkey, 0) < 0) {
log_warn(LD_OR, "The signing cert we loaded was not signed "
"correctly: %s!",
tor_cert_describe_signature_status(sign_cert));
goto err;
}
}
if (want_new_signing_key && sign_signing_key_with_id) {
uint32_t flags = (INIT_ED_KEY_CREATE|
INIT_ED_KEY_REPLACE|
INIT_ED_KEY_EXTRA_STRONG|
INIT_ED_KEY_NEEDCERT|
INIT_ED_KEY_INCLUDE_SIGNING_KEY_IN_CERT);
char *fname =
options_get_keydir_fname(options, "ed25519_signing");
ed25519_keypair_free(sign);
tor_cert_free(sign_cert);
sign = ed_key_init_from_file(fname,
flags, LOG_WARN,
sign_signing_key_with_id, now,
options->SigningKeyLifetime,
CERT_TYPE_ID_SIGNING, &sign_cert);
tor_free(fname);
if (!sign)
FAIL("Missing signing key");
use_signing = sign;
signing_key_changed = 1;
tor_assert(sign_cert->signing_key_included);
tor_assert(ed25519_pubkey_eq(&sign_cert->signing_key, &id->pubkey));
tor_assert(ed25519_pubkey_eq(&sign_cert->signed_key, &sign->pubkey));
} else if (want_new_signing_key) {
static ratelim_t missing_master = RATELIM_INIT(3600);
log_fn_ratelim(&missing_master, LOG_WARN, LD_OR,
"Signing key will expire soon, but I can't load the "
"master key to sign a new one!");
}
tor_assert(use_signing);
/* At this point we no longer need our secret identity key. So wipe
* it, if we loaded it in the first place. */
memwipe(id->seckey.seckey, 0, sizeof(id->seckey));
if (options->command == CMD_KEYGEN)
goto end;
if (server_mode(options) &&
(!rsa_ed_crosscert ||
HAPPENS_SOON(rsa_ed_crosscert_expiration, 30*86400))) {
uint8_t *crosscert;
time_t expiration = now+6*30*86400; /* 6 months in the future. */
ssize_t crosscert_len = tor_make_rsa_ed25519_crosscert(&id->pubkey,
get_server_identity_key(),
expiration,
&crosscert);
tor_free(rsa_ed_crosscert);
rsa_ed_crosscert_len = crosscert_len;
rsa_ed_crosscert = crosscert;
rsa_ed_crosscert_expiration = expiration;
}
if (!current_auth_key ||
signing_key_changed ||
EXPIRES_SOON(auth_key_cert, options->TestingAuthKeySlop)) {
auth = ed_key_new(use_signing, INIT_ED_KEY_NEEDCERT,
now,
options->TestingAuthKeyLifetime,
CERT_TYPE_SIGNING_AUTH, &auth_cert);
if (!auth)
FAIL("Can't create auth key");
}
/* We've generated or loaded everything. Put them in memory. */
end:
if (! master_identity_key) {
SET_KEY(master_identity_key, id);
} else {
tor_free(id);
}
if (sign) {
SET_KEY(master_signing_key, sign);
SET_CERT(signing_key_cert, sign_cert);
}
if (auth) {
SET_KEY(current_auth_key, auth);
SET_CERT(auth_key_cert, auth_cert);
}
return signing_key_changed;
err:
ed25519_keypair_free(id);
ed25519_keypair_free(sign);
ed25519_keypair_free(auth);
tor_cert_free(sign_cert);
tor_cert_free(auth_cert);
return -1;
}
/**
* Retrieve our currently-in-use Ed25519 link certificate and id certificate,
* and, if they would expire soon (based on the time <b>now</b>, generate new
* certificates (without embedding the public part of the signing key inside).
* If <b>force</b> is true, always generate a new certificate.
*
* The signed_key from the current id->signing certificate will be used to
* sign the new key within newly generated X509 certificate.
*
* Returns -1 upon error. Otherwise, returns 0 upon success (either when the
* current certificate is still valid, or when a new certificate was
* successfully generated, or no certificate was needed).
*/
int
generate_ed_link_cert(const or_options_t *options, time_t now,
int force)
{
const tor_x509_cert_t *link_ = NULL, *id = NULL;
tor_cert_t *link_cert = NULL;
if (tor_tls_get_my_certs(1, &link_, &id) < 0 || link_ == NULL) {
if (!server_mode(options)) {
/* No need to make an Ed25519->Link cert: we are a client */
return 0;
}
log_warn(LD_OR, "Can't get my x509 link cert.");
return -1;
}
const common_digests_t *digests = tor_x509_cert_get_cert_digests(link_);
if (force == 0 &&
link_cert_cert &&
! EXPIRES_SOON(link_cert_cert, options->TestingLinkKeySlop) &&
fast_memeq(digests->d[DIGEST_SHA256], link_cert_cert->signed_key.pubkey,
DIGEST256_LEN)) {
return 0;
}
ed25519_public_key_t dummy_key;
memcpy(dummy_key.pubkey, digests->d[DIGEST_SHA256], DIGEST256_LEN);
link_cert = tor_cert_create(get_master_signing_keypair(),
CERT_TYPE_SIGNING_LINK,
&dummy_key,
now,
options->TestingLinkCertLifetime, 0);
if (link_cert) {
SET_CERT(link_cert_cert, link_cert);
}
return 0;
}
#undef FAIL
#undef SET_KEY
#undef SET_CERT
/**
* Return 1 if any of the following are true:
*
* - if one of our Ed25519 signing, auth, or link certificates would expire
* soon w.r.t. the time <b>now</b>,
* - if we do not currently have a link certificate, or
* - if our cached Ed25519 link certificate is not same as the one we're
* currently using.
*
* Otherwise, returns 0.
*/
int
should_make_new_ed_keys(const or_options_t *options, const time_t now)
{
if (!master_identity_key ||
!master_signing_key ||
!current_auth_key ||
!link_cert_cert ||
EXPIRES_SOON(signing_key_cert, options->TestingSigningKeySlop) ||
EXPIRES_SOON(auth_key_cert, options->TestingAuthKeySlop) ||
EXPIRES_SOON(link_cert_cert, options->TestingLinkKeySlop))
return 1;
const tor_x509_cert_t *link_ = NULL, *id = NULL;
if (tor_tls_get_my_certs(1, &link_, &id) < 0 || link_ == NULL)
return 1;
const common_digests_t *digests = tor_x509_cert_get_cert_digests(link_);
if (!fast_memeq(digests->d[DIGEST_SHA256],
link_cert_cert->signed_key.pubkey,
DIGEST256_LEN)) {
return 1;
}
return 0;
}
#undef EXPIRES_SOON
#undef HAPPENS_SOON
#ifdef TOR_UNIT_TESTS
/* Helper for unit tests: populate the ed25519 keys without saving or
* loading */
void
init_mock_ed_keys(const crypto_pk_t *rsa_identity_key)
{
routerkeys_free_all();
#define MAKEKEY(k) \
k = tor_malloc_zero(sizeof(*k)); \
if (ed25519_keypair_generate(k, 0) < 0) { \
log_warn(LD_BUG, "Couldn't make a keypair"); \
goto err; \
}
MAKEKEY(master_identity_key);
MAKEKEY(master_signing_key);
MAKEKEY(current_auth_key);
#define MAKECERT(cert, signing, signed_, type, flags) \
cert = tor_cert_create(signing, \
type, \
&signed_->pubkey, \
time(NULL), 86400, \
flags); \
if (!cert) { \
log_warn(LD_BUG, "Couldn't make a %s certificate!", #cert); \
goto err; \
}
MAKECERT(signing_key_cert,
master_identity_key, master_signing_key, CERT_TYPE_ID_SIGNING,
CERT_FLAG_INCLUDE_SIGNING_KEY);
MAKECERT(auth_key_cert,
master_signing_key, current_auth_key, CERT_TYPE_SIGNING_AUTH, 0);
if (generate_ed_link_cert(get_options(), time(NULL), 0) < 0) {
log_warn(LD_BUG, "Couldn't make link certificate");
goto err;
}
rsa_ed_crosscert_len = tor_make_rsa_ed25519_crosscert(
&master_identity_key->pubkey,
rsa_identity_key,
time(NULL)+86400,
&rsa_ed_crosscert);
return;
err:
routerkeys_free_all();
tor_assert_nonfatal_unreached();
}
#undef MAKEKEY
#undef MAKECERT
#endif /* defined(TOR_UNIT_TESTS) */
/**
* Print the ISO8601-formated <b>expiration</b> for a certificate with
* some <b>description</b> to stdout.
*
* For example, for a signing certificate, this might print out:
* signing-cert-expiry: 2017-07-25 08:30:15 UTC
*/
static void
print_cert_expiration(const char *expiration,
const char *description)
{
fprintf(stderr, "%s-cert-expiry: %s\n", description, expiration);
}
/**
* Log when a certificate, <b>cert</b>, with some <b>description</b> and
* stored in a file named <b>fname</b>, is going to expire.
*/
static void
log_ed_cert_expiration(const tor_cert_t *cert,
const char *description,
const char *fname) {
char expiration[ISO_TIME_LEN+1];
if (BUG(!cert)) { /* If the specified key hasn't been loaded */
log_warn(LD_OR, "No %s key loaded; can't get certificate expiration.",
description);
} else {
format_local_iso_time(expiration, cert->valid_until);
log_notice(LD_OR, "The %s certificate stored in %s is valid until %s.",
description, fname, expiration);
print_cert_expiration(expiration, description);
}
}
/**
* Log when our master signing key certificate expires. Used when tor is given
* the --key-expiration command-line option.
*
* Returns 0 on success and 1 on failure.
*/
static int
log_master_signing_key_cert_expiration(const or_options_t *options)
{
const tor_cert_t *signing_key;
char *fn = NULL;
int failed = 0;
time_t now = approx_time();
fn = options_get_keydir_fname(options, "ed25519_signing_cert");
/* Try to grab our cached copy of the key. */
signing_key = get_master_signing_key_cert();
tor_assert(server_identity_key_is_set());
/* Load our keys from disk, if necessary. */
if (!signing_key) {
failed = load_ed_keys(options, now) < 0;
signing_key = get_master_signing_key_cert();
}
/* If we do have a signing key, log the expiration time. */
if (signing_key) {
log_ed_cert_expiration(signing_key, "signing", fn);
} else {
log_warn(LD_OR, "Could not load signing key certificate from %s, so " \
"we couldn't learn anything about certificate expiration.", fn);
}
tor_free(fn);
return failed;
}
/**
* Log when a key certificate expires. Used when tor is given the
* --key-expiration command-line option.
*
* If an command argument is given, which should specify the type of
* key to get expiry information about (currently supported arguments
* are "sign"), get info about that type of certificate. Otherwise,
* print info about the supported arguments.
*
* Returns 0 on success and -1 on failure.
*/
int
log_cert_expiration(void)
{
const or_options_t *options = get_options();
const char *arg = options->command_arg;
if (!strcmp(arg, "sign")) {
return log_master_signing_key_cert_expiration(options);
} else {
fprintf(stderr, "No valid argument to --key-expiration found!\n");
fprintf(stderr, "Currently recognised arguments are: 'sign'\n");
return -1;
}
}
const ed25519_public_key_t *
get_master_identity_key(void)
{
if (!master_identity_key)
return NULL;
return &master_identity_key->pubkey;
}
/** Return true iff <b>id</b> is our Ed25519 master identity key. */
int
router_ed25519_id_is_me(const ed25519_public_key_t *id)
{
return id && master_identity_key &&
ed25519_pubkey_eq(id, &master_identity_key->pubkey);
}
#ifdef TOR_UNIT_TESTS
/* only exists for the unit tests, since otherwise the identity key
* should be used to sign nothing but the signing key. */
const ed25519_keypair_t *
get_master_identity_keypair(void)
{
return master_identity_key;
}
#endif /* defined(TOR_UNIT_TESTS) */
const ed25519_keypair_t *
get_master_signing_keypair(void)
{
return master_signing_key;
}
const struct tor_cert_st *
get_master_signing_key_cert(void)
{
return signing_key_cert;
}
const ed25519_keypair_t *
get_current_auth_keypair(void)
{
return current_auth_key;
}
const tor_cert_t *
get_current_link_cert_cert(void)
{
return link_cert_cert;
}
const tor_cert_t *
get_current_auth_key_cert(void)
{
return auth_key_cert;
}
void
get_master_rsa_crosscert(const uint8_t **cert_out,
size_t *size_out)
{
*cert_out = rsa_ed_crosscert;
*size_out = rsa_ed_crosscert_len;
}
/** Construct cross-certification for the master identity key with
* the ntor onion key. Store the sign of the corresponding ed25519 public key
* in *<b>sign_out</b>. */
tor_cert_t *
make_ntor_onion_key_crosscert(const curve25519_keypair_t *onion_key,
const ed25519_public_key_t *master_id_key, time_t now, time_t lifetime,
int *sign_out)
{
tor_cert_t *cert = NULL;
ed25519_keypair_t ed_onion_key;
if (ed25519_keypair_from_curve25519_keypair(&ed_onion_key, sign_out,
onion_key) < 0)
goto end;
cert = tor_cert_create(&ed_onion_key, CERT_TYPE_ONION_ID, master_id_key,
now, lifetime, 0);
end:
memwipe(&ed_onion_key, 0, sizeof(ed_onion_key));
return cert;
}
/** Construct and return an RSA signature for the TAP onion key to
* cross-certify the RSA and Ed25519 identity keys. Set <b>len_out</b> to its
* length. */
uint8_t *
make_tap_onion_key_crosscert(const crypto_pk_t *onion_key,
const ed25519_public_key_t *master_id_key,
const crypto_pk_t *rsa_id_key,
int *len_out)
{
uint8_t signature[PK_BYTES];
uint8_t signed_data[DIGEST_LEN + ED25519_PUBKEY_LEN];
*len_out = 0;
if (crypto_pk_get_digest(rsa_id_key, (char*)signed_data) < 0) {
return NULL;
}
memcpy(signed_data + DIGEST_LEN, master_id_key->pubkey, ED25519_PUBKEY_LEN);
int r = crypto_pk_private_sign(onion_key,
(char*)signature, sizeof(signature),
(const char*)signed_data, sizeof(signed_data));
if (r < 0)
return NULL;
*len_out = r;
return tor_memdup(signature, r);
}
/** Check whether an RSA-TAP cross-certification is correct. Return 0 if it
* is, -1 if it isn't. */
MOCK_IMPL(int,
check_tap_onion_key_crosscert,(const uint8_t *crosscert,
int crosscert_len,
const crypto_pk_t *onion_pkey,
const ed25519_public_key_t *master_id_pkey,
const uint8_t *rsa_id_digest))
{
uint8_t *cc = tor_malloc(crypto_pk_keysize(onion_pkey));
int cc_len =
crypto_pk_public_checksig(onion_pkey,
(char*)cc,
crypto_pk_keysize(onion_pkey),
(const char*)crosscert,
crosscert_len);
if (cc_len < 0) {
goto err;
}
if (cc_len < DIGEST_LEN + ED25519_PUBKEY_LEN) {
log_warn(LD_DIR, "Short signature on cross-certification with TAP key");
goto err;
}
if (tor_memneq(cc, rsa_id_digest, DIGEST_LEN) ||
tor_memneq(cc + DIGEST_LEN, master_id_pkey->pubkey,
ED25519_PUBKEY_LEN)) {
log_warn(LD_DIR, "Incorrect cross-certification with TAP key");
goto err;
}
tor_free(cc);
return 0;
err:
tor_free(cc);
return -1;
}
void
routerkeys_free_all(void)
{
ed25519_keypair_free(master_identity_key);
ed25519_keypair_free(master_signing_key);
ed25519_keypair_free(current_auth_key);
tor_cert_free(signing_key_cert);
tor_cert_free(link_cert_cert);
tor_cert_free(auth_key_cert);
tor_free(rsa_ed_crosscert);
master_identity_key = master_signing_key = NULL;
current_auth_key = NULL;
signing_key_cert = link_cert_cert = auth_key_cert = NULL;
rsa_ed_crosscert = NULL; // redundant
rsa_ed_crosscert_len = 0;
}
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