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Diffstat (limited to 'src/util/taler-exchange-secmod-cs.c')
| -rw-r--r-- | src/util/taler-exchange-secmod-cs.c | 1580 |
1 files changed, 1580 insertions, 0 deletions
diff --git a/src/util/taler-exchange-secmod-cs.c b/src/util/taler-exchange-secmod-cs.c new file mode 100644 index 000000000..12a1fbbd0 --- /dev/null +++ b/src/util/taler-exchange-secmod-cs.c @@ -0,0 +1,1580 @@ +/* + This file is part of TALER + Copyright (C) 2014-2021 Taler Systems SA + + TALER is free software; you can redistribute it and/or modify it under the + terms of the GNU General Public License as published by the Free Software + Foundation; either version 3, or (at your option) any later version. + + TALER is distributed in the hope that it will be useful, but WITHOUT ANY + WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR + A PARTICULAR PURPOSE. See the GNU General Public License for more details. + + You should have received a copy of the GNU General Public License along with + TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/> +*/ +/** + * @file util/taler-exchange-secmod-cs.c + * @brief Standalone process to perform private key CS operations + * @author Christian Grothoff + * + * Key design points: + * - EVERY thread of the exchange will have its own pair of connections to the + * crypto helpers. This way, every thread will also have its own /keys state + * and avoid the need to synchronize on those. + * - auditor signatures and master signatures are to be kept in the exchange DB, + * and merged with the public keys of the helper by the exchange HTTPD! + * - the main loop of the helper is SINGLE-THREADED, but there are + * threads for crypto-workers which do the signing in parallel, one per client. + * - thread-safety: signing happens in parallel, thus when REMOVING private keys, + * we must ensure that all signers are done before we fully free() the + * private key. This is done by reference counting (as work is always + * assigned and collected by the main thread). + */ +#include "platform.h" +#include "taler_util.h" +#include "taler-exchange-secmod-cs.h" +#include <gcrypt.h> +#include <pthread.h> +#include <sys/eventfd.h> +#include "taler_error_codes.h" +#include "taler_signatures.h" +#include "secmod_common.h" +#include <poll.h> + + +/** + * Information we keep per denomination. + */ +struct Denomination; + + +/** + * One particular denomination key. + */ +struct DenominationKey +{ + + /** + * Kept in a DLL of the respective denomination. Sorted by anchor time. + */ + struct DenominationKey *next; + + /** + * Kept in a DLL of the respective denomination. Sorted by anchor time. + */ + struct DenominationKey *prev; + + /** + * Denomination this key belongs to. + */ + struct Denomination *denom; + + /** + * Name of the file this key is stored under. + */ + char *filename; + + /** + * The private key of the denomination. + */ + struct GNUNET_CRYPTO_RsaPrivateKey *denom_priv; + + /** + * The public key of the denomination. + */ + struct GNUNET_CRYPTO_RsaPublicKey *denom_pub; + + /** + * Message to transmit to clients to introduce this public key. + */ + struct TALER_CRYPTO_CsKeyAvailableNotification *an; + + /** + * Hash of this denomination's public key. + */ + struct TALER_CsPubHashP h_cs; + + /** + * Time at which this key is supposed to become valid. + */ + struct GNUNET_TIME_Timestamp anchor; + + /** + * Generation when this key was created or revoked. + */ + uint64_t key_gen; + + /** + * Reference counter. Counts the number of threads that are + * using this key at this time. + */ + unsigned int rc; + + /** + * Flag set to true if this key has been purged and the memory + * must be freed as soon as @e rc hits zero. + */ + bool purge; + +}; + + +struct Denomination +{ + + /** + * Kept in a DLL. Sorted by #denomination_action_time(). + */ + struct Denomination *next; + + /** + * Kept in a DLL. Sorted by #denomination_action_time(). + */ + struct Denomination *prev; + + /** + * Head of DLL of actual keys of this denomination. + */ + struct DenominationKey *keys_head; + + /** + * Tail of DLL of actual keys of this denomination. + */ + struct DenominationKey *keys_tail; + + /** + * How long can coins be withdrawn (generated)? Should be small + * enough to limit how many coins will be signed into existence with + * the same key, but large enough to still provide a reasonable + * anonymity set. + */ + struct GNUNET_TIME_Relative duration_withdraw; + + /** + * What is the configuration section of this denomination type? Also used + * for the directory name where the denomination keys are stored. + */ + char *section; + + /** + * Length of (new) CS keys (in bits). + */ + uint32_t rsa_keysize; +}; + + +/** + * Return value from main(). + */ +static int global_ret; + +/** + * Time when the key update is executed. + * Either the actual current time, or a pretended time. + */ +static struct GNUNET_TIME_Timestamp now; + +/** + * The time for the key update, as passed by the user + * on the command line. + */ +static struct GNUNET_TIME_Timestamp now_tmp; + +/** + * Where do we store the keys? + */ +static char *keydir; + +/** + * How much should coin creation (@e duration_withdraw) duration overlap + * with the next denomination? Basically, the starting time of two + * denominations is always @e duration_withdraw - #overlap_duration apart. + */ +static struct GNUNET_TIME_Relative overlap_duration; + +/** + * How long into the future do we pre-generate keys? + */ +static struct GNUNET_TIME_Relative lookahead_sign; + +/** + * All of our denominations, in a DLL. Sorted? + */ +static struct Denomination *denom_head; + +/** + * All of our denominations, in a DLL. Sorted? + */ +static struct Denomination *denom_tail; + +/** + * Map of hashes of public (CS) keys to `struct DenominationKey *` + * with the respective private keys. + */ +static struct GNUNET_CONTAINER_MultiHashMap *keys; + +/** + * Task run to generate new keys. + */ +static struct GNUNET_SCHEDULER_Task *keygen_task; + +/** + * Lock for the keys queue. + */ +static pthread_mutex_t keys_lock; + +/** + * Current key generation. + */ +static uint64_t key_gen; + + +/** + * Generate the announcement message for @a dk. + * + * @param[in,out] denomination key to generate the announcement for + */ +static void +generate_response (struct DenominationKey *dk) +{ + struct Denomination *denom = dk->denom; + size_t nlen = strlen (denom->section) + 1; + struct TALER_CRYPTO_CsKeyAvailableNotification *an; + size_t buf_len; + void *buf; + void *p; + size_t tlen; + + buf_len = GNUNET_CRYPTO_rsa_public_key_encode (dk->denom_pub, + &buf); + GNUNET_assert (buf_len < UINT16_MAX); + GNUNET_assert (nlen < UINT16_MAX); + tlen = buf_len + nlen + sizeof (*an); + GNUNET_assert (tlen < UINT16_MAX); + an = GNUNET_malloc (tlen); + an->header.size = htons ((uint16_t) tlen); + an->header.type = htons (TALER_HELPER_CS_MT_AVAIL); + an->pub_size = htons ((uint16_t) buf_len); + an->section_name_len = htons ((uint16_t) nlen); + an->anchor_time = GNUNET_TIME_timestamp_hton (dk->anchor); + an->duration_withdraw = GNUNET_TIME_relative_hton (denom->duration_withdraw); + TALER_exchange_secmod_cs_sign (&dk->h_cs, + denom->section, + dk->anchor, + denom->duration_withdraw, + &TES_smpriv, + &an->secm_sig); + an->secm_pub = TES_smpub; + p = (void *) &an[1]; + memcpy (p, + buf, + buf_len); + GNUNET_free (buf); + memcpy (p + buf_len, + denom->section, + nlen); + dk->an = an; +} + + +/** + * Handle @a client request @a sr to create signature. Create the + * signature using the respective key and return the result to + * the client. + * + * @param client the client making the request + * @param sr the request details + * @return #GNUNET_OK on success + */ +static enum GNUNET_GenericReturnValue +handle_sign_request (struct TES_Client *client, + const struct TALER_CRYPTO_CsSignRequest *sr) +{ + struct DenominationKey *dk; + const void *blinded_msg = &sr[1]; + size_t blinded_msg_size = ntohs (sr->header.size) - sizeof (*sr); + struct GNUNET_CRYPTO_RsaSignature *rsa_signature; + struct GNUNET_TIME_Absolute now = GNUNET_TIME_absolute_get (); + + GNUNET_assert (0 == pthread_mutex_lock (&keys_lock)); + dk = GNUNET_CONTAINER_multihashmap_get (keys, + &sr->h_cs.hash); + if (NULL == dk) + { + struct TALER_CRYPTO_SignFailure sf = { + .header.size = htons (sizeof (sr)), + .header.type = htons (TALER_HELPER_CS_MT_RES_SIGN_FAILURE), + .ec = htonl (TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN) + }; + + GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock)); + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + "Signing request failed, denomination key %s unknown\n", + GNUNET_h2s (&sr->h_cs.hash)); + return TES_transmit (client->csock, + &sf.header); + } + if (GNUNET_TIME_absolute_is_future (dk->anchor.abs_time)) + { + /* it is too early */ + struct TALER_CRYPTO_SignFailure sf = { + .header.size = htons (sizeof (sr)), + .header.type = htons (TALER_HELPER_CS_MT_RES_SIGN_FAILURE), + .ec = htonl (TALER_EC_EXCHANGE_DENOMINATION_HELPER_TOO_EARLY) + }; + + GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock)); + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + "Signing request failed, denomination key %s is not yet valid\n", + GNUNET_h2s (&sr->h_cs.hash)); + return TES_transmit (client->csock, + &sf.header); + } + + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + "Received request to sign over %u bytes with key %s\n", + (unsigned int) blinded_msg_size, + GNUNET_h2s (&sr->h_cs.hash)); + GNUNET_assert (dk->rc < UINT_MAX); + dk->rc++; + GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock)); + rsa_signature + = GNUNET_CRYPTO_rsa_sign_blinded (dk->denom_priv, + blinded_msg, + blinded_msg_size); + GNUNET_assert (0 == pthread_mutex_lock (&keys_lock)); + GNUNET_assert (dk->rc > 0); + dk->rc--; + GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock)); + if (NULL == rsa_signature) + { + struct TALER_CRYPTO_SignFailure sf = { + .header.size = htons (sizeof (sf)), + .header.type = htons (TALER_HELPER_CS_MT_RES_SIGN_FAILURE), + .ec = htonl (TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE) + }; + + GNUNET_log (GNUNET_ERROR_TYPE_WARNING, + "Signing request failed, worker failed to produce signature\n"); + return TES_transmit (client->csock, + &sf.header); + } + + { + struct TALER_CRYPTO_SignResponse *sr; + void *buf; + size_t buf_size; + size_t tsize; + enum GNUNET_GenericReturnValue ret; + + buf_size = GNUNET_CRYPTO_rsa_signature_encode (rsa_signature, + &buf); + GNUNET_CRYPTO_rsa_signature_free (rsa_signature); + tsize = sizeof (*sr) + buf_size; + GNUNET_assert (tsize < UINT16_MAX); + sr = GNUNET_malloc (tsize); + sr->header.size = htons (tsize); + sr->header.type = htons (TALER_HELPER_CS_MT_RES_SIGNATURE); + memcpy (&sr[1], + buf, + buf_size); + GNUNET_free (buf); + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + "Sending CS signature after %s\n", + GNUNET_TIME_relative2s ( + GNUNET_TIME_absolute_get_duration (now), + GNUNET_YES)); + ret = TES_transmit (client->csock, + &sr->header); + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + "Sent CS signature after %s\n", + GNUNET_TIME_relative2s ( + GNUNET_TIME_absolute_get_duration (now), + GNUNET_YES)); + GNUNET_free (sr); + return ret; + } +} + + +/** + * Initialize key material for denomination key @a dk (also on disk). + * + * @param[in,out] dk denomination key to compute key material for + * @param position where in the DLL will the @a dk go + * @return #GNUNET_OK on success + */ +static enum GNUNET_GenericReturnValue +setup_key (struct DenominationKey *dk, + struct DenominationKey *position) +{ + struct Denomination *denom = dk->denom; + struct GNUNET_CRYPTO_RsaPrivateKey *priv; + struct GNUNET_CRYPTO_RsaPublicKey *pub; + size_t buf_size; + void *buf; + + priv = GNUNET_CRYPTO_rsa_private_key_create (denom->rsa_keysize); + if (NULL == priv) + { + GNUNET_break (0); + GNUNET_SCHEDULER_shutdown (); + global_ret = EXIT_FAILURE; + return GNUNET_SYSERR; + } + pub = GNUNET_CRYPTO_rsa_private_key_get_public (priv); + if (NULL == pub) + { + GNUNET_break (0); + GNUNET_CRYPTO_rsa_private_key_free (priv); + return GNUNET_SYSERR; + } + buf_size = GNUNET_CRYPTO_rsa_private_key_encode (priv, + &buf); + TALER_rsa_pub_hash (pub, + &dk->h_cs); + GNUNET_asprintf (&dk->filename, + "%s/%s/%llu", + keydir, + denom->section, + (unsigned long long) (dk->anchor.abs_time.abs_value_us + / GNUNET_TIME_UNIT_SECONDS.rel_value_us)); + if (GNUNET_OK != + GNUNET_DISK_fn_write (dk->filename, + buf, + buf_size, + GNUNET_DISK_PERM_USER_READ)) + { + GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR, + "write", + dk->filename); + GNUNET_free (buf); + GNUNET_CRYPTO_rsa_private_key_free (priv); + GNUNET_CRYPTO_rsa_public_key_free (pub); + return GNUNET_SYSERR; + } + GNUNET_free (buf); + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + "Setup fresh private key %s at %s in `%s' (generation #%llu)\n", + GNUNET_h2s (&dk->h_cs.hash), + GNUNET_TIME_timestamp2s (dk->anchor), + dk->filename, + (unsigned long long) key_gen); + dk->denom_priv = priv; + dk->denom_pub = pub; + dk->key_gen = key_gen; + generate_response (dk); + if (GNUNET_OK != + GNUNET_CONTAINER_multihashmap_put ( + keys, + &dk->h_cs.hash, + dk, + GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)) + { + GNUNET_log (GNUNET_ERROR_TYPE_ERROR, + "Duplicate private key created! Terminating.\n"); + GNUNET_CRYPTO_rsa_private_key_free (dk->denom_priv); + GNUNET_CRYPTO_rsa_public_key_free (dk->denom_pub); + GNUNET_free (dk->filename); + GNUNET_free (dk->an); + GNUNET_free (dk); + return GNUNET_SYSERR; + } + GNUNET_CONTAINER_DLL_insert_after (denom->keys_head, + denom->keys_tail, + position, + dk); + return GNUNET_OK; +} + + +/** + * The withdraw period of a key @a dk has expired. Purge it. + * + * @param[in] dk expired denomination key to purge + */ +static void +purge_key (struct DenominationKey *dk) +{ + if (dk->purge) + return; + if (0 != unlink (dk->filename)) + GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR, + "unlink", + dk->filename); + GNUNET_free (dk->filename); + dk->purge = true; + dk->key_gen = key_gen; +} + + +/** + * A @a client informs us that a key has been revoked. + * Check if the key is still in use, and if so replace (!) + * it with a fresh key. + * + * @param client the client making the request + * @param rr the revocation request + */ +static enum GNUNET_GenericReturnValue +handle_revoke_request (struct TES_Client *client, + const struct TALER_CRYPTO_CsRevokeRequest *rr) +{ + struct DenominationKey *dk; + struct DenominationKey *ndk; + struct Denomination *denom; + + (void) client; + GNUNET_assert (0 == pthread_mutex_lock (&keys_lock)); + dk = GNUNET_CONTAINER_multihashmap_get (keys, + &rr->h_cs.hash); + if (NULL == dk) + { + GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock)); + GNUNET_log (GNUNET_ERROR_TYPE_WARNING, + "Revocation request ignored, denomination key %s unknown\n", + GNUNET_h2s (&rr->h_cs.hash)); + return GNUNET_OK; + } + if (dk->purge) + { + GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock)); + GNUNET_log (GNUNET_ERROR_TYPE_WARNING, + "Revocation request ignored, denomination key %s already revoked\n", + GNUNET_h2s (&rr->h_cs.hash)); + return GNUNET_OK; + } + + key_gen++; + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + "Revoking key %s, bumping generation to %llu\n", + GNUNET_h2s (&rr->h_cs.hash), + (unsigned long long) key_gen); + purge_key (dk); + + /* Setup replacement key */ + denom = dk->denom; + ndk = GNUNET_new (struct DenominationKey); + ndk->denom = denom; + ndk->anchor = dk->anchor; + if (GNUNET_OK != + setup_key (ndk, + dk)) + { + GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock)); + GNUNET_break (0); + GNUNET_SCHEDULER_shutdown (); + global_ret = EXIT_FAILURE; + return GNUNET_SYSERR; + } + GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock)); + TES_wake_clients (); + return GNUNET_OK; +} + + +/** + * Handle @a hdr message received from @a client. + * + * @param client the client that received the message + * @param hdr message that was received + * @return #GNUNET_OK on success + */ +static enum GNUNET_GenericReturnValue +cs_work_dispatch (struct TES_Client *client, + const struct GNUNET_MessageHeader *hdr) +{ + uint16_t msize = ntohs (hdr->size); + + switch (ntohs (hdr->type)) + { + case TALER_HELPER_CS_MT_REQ_SIGN: + if (msize <= sizeof (struct TALER_CRYPTO_CsSignRequest)) + { + GNUNET_break_op (0); + return GNUNET_SYSERR; + } + return handle_sign_request ( + client, + (const struct TALER_CRYPTO_CsSignRequest *) hdr); + case TALER_HELPER_CS_MT_REQ_REVOKE: + if (msize != sizeof (struct TALER_CRYPTO_CsRevokeRequest)) + { + GNUNET_break_op (0); + return GNUNET_SYSERR; + } + return handle_revoke_request ( + client, + (const struct TALER_CRYPTO_CsRevokeRequest *) hdr); + default: + GNUNET_break_op (0); + return GNUNET_SYSERR; + } +} + + +/** + * Send our initial key set to @a client together with the + * "sync" terminator. + * + * @param client the client to inform + * @return #GNUNET_OK on success + */ +static enum GNUNET_GenericReturnValue +cs_client_init (struct TES_Client *client) +{ + size_t obs = 0; + char *buf; + + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + "Initializing new client %p\n", + client); + GNUNET_assert (0 == pthread_mutex_lock (&keys_lock)); + for (struct Denomination *denom = denom_head; + NULL != denom; + denom = denom->next) + { + for (struct DenominationKey *dk = denom->keys_head; + NULL != dk; + dk = dk->next) + { + obs += ntohs (dk->an->header.size); + } + } + buf = GNUNET_malloc (obs); + obs = 0; + for (struct Denomination *denom = denom_head; + NULL != denom; + denom = denom->next) + { + for (struct DenominationKey *dk = denom->keys_head; + NULL != dk; + dk = dk->next) + { + memcpy (&buf[obs], + dk->an, + ntohs (dk->an->header.size)); + obs += ntohs (dk->an->header.size); + } + } + client->key_gen = key_gen; + GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock)); + if (GNUNET_OK != + TES_transmit_raw (client->csock, + obs, + buf)) + { + GNUNET_free (buf); + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + "Client %p must have disconnected\n", + client); + return GNUNET_SYSERR; + } + GNUNET_free (buf); + { + struct GNUNET_MessageHeader synced = { + .type = htons (TALER_HELPER_CS_SYNCED), + .size = htons (sizeof (synced)) + }; + + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + "Sending CS SYNCED message to %p\n", + client); + if (GNUNET_OK != + TES_transmit (client->csock, + &synced)) + { + GNUNET_break (0); + return GNUNET_SYSERR; + } + } + return GNUNET_OK; +} + + +/** + * Notify @a client about all changes to the keys since + * the last generation known to the @a client. + * + * @param client the client to notify + * @return #GNUNET_OK on success + */ +static enum GNUNET_GenericReturnValue +cs_update_client_keys (struct TES_Client *client) +{ + size_t obs = 0; + char *buf; + enum GNUNET_GenericReturnValue ret; + + GNUNET_assert (0 == pthread_mutex_lock (&keys_lock)); + for (struct Denomination *denom = denom_head; + NULL != denom; + denom = denom->next) + { + for (struct DenominationKey *key = denom->keys_head; + NULL != key; + key = key->next) + { + if (key->key_gen <= client->key_gen) + continue; + if (key->purge) + obs += sizeof (struct TALER_CRYPTO_CsKeyPurgeNotification); + else + obs += ntohs (key->an->header.size); + } + } + if (0 == obs) + { + /* nothing to do */ + client->key_gen = key_gen; + GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock)); + return GNUNET_OK; + } + buf = GNUNET_malloc (obs); + obs = 0; + for (struct Denomination *denom = denom_head; + NULL != denom; + denom = denom->next) + { + for (struct DenominationKey *key = denom->keys_head; + NULL != key; + key = key->next) + { + if (key->key_gen <= client->key_gen) + continue; + if (key->purge) + { + struct TALER_CRYPTO_CsKeyPurgeNotification pn = { + .header.type = htons (TALER_HELPER_CS_MT_PURGE), + .header.size = htons (sizeof (pn)), + .h_cs = key->h_cs + }; + + memcpy (&buf[obs], + &pn, + sizeof (pn)); + obs += sizeof (pn); + } + else + { + memcpy (&buf[obs], + key->an, + ntohs (key->an->header.size)); + obs += ntohs (key->an->header.size); + } + } + } + client->key_gen = key_gen; + GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock)); + ret = TES_transmit_raw (client->csock, + obs, + buf); + GNUNET_free (buf); + return ret; +} + + +/** + * Create a new denomination key (we do not have enough). + * + * @param denom denomination key to create + * @param now current time to use (to get many keys to use the exact same time) + * @return #GNUNET_OK on success + */ +static enum GNUNET_GenericReturnValue +create_key (struct Denomination *denom, + struct GNUNET_TIME_Timestamp now) +{ + struct DenominationKey *dk; + struct GNUNET_TIME_Timestamp anchor; + + anchor = now; + if (NULL != denom->keys_tail) + { + struct GNUNET_TIME_Absolute abs; + + abs = GNUNET_TIME_absolute_add (denom->keys_tail->anchor.abs_time, + GNUNET_TIME_relative_subtract ( + denom->duration_withdraw, + overlap_duration)); + if (GNUNET_TIME_absolute_cmp (now.abs_time, <, abs)) + anchor = GNUNET_TIME_absolute_to_timestamp (abs); + } + dk = GNUNET_new (struct DenominationKey); + dk->denom = denom; + dk->anchor = anchor; + if (GNUNET_OK != + setup_key (dk, + denom->keys_tail)) + { + GNUNET_break (0); + GNUNET_free (dk); + GNUNET_SCHEDULER_shutdown (); + global_ret = EXIT_FAILURE; + return GNUNET_SYSERR; + } + return GNUNET_OK; +} + + +/** + * At what time does this denomination require its next action? + * Basically, the minimum of the withdraw expiration time of the + * oldest denomination key, and the withdraw expiration time of + * the newest denomination key minus the #lookahead_sign time. + * + * @param denom denomination to compute action time for + */ +static struct GNUNET_TIME_Absolute +denomination_action_time (const struct Denomination *denom) +{ + struct DenominationKey *head = denom->keys_head; + struct DenominationKey *tail = denom->keys_tail; + struct GNUNET_TIME_Absolute tt; + + if (NULL == head) + return GNUNET_TIME_UNIT_ZERO_ABS; + tt = GNUNET_TIME_absolute_subtract ( + GNUNET_TIME_absolute_subtract ( + GNUNET_TIME_absolute_add (tail->anchor.abs_time, + denom->duration_withdraw), + lookahead_sign), + overlap_duration); + if (head->rc > 0) + return tt; /* head expiration does not count due to rc > 0 */ + return GNUNET_TIME_absolute_min ( + GNUNET_TIME_absolute_add (head->anchor.abs_time, + denom->duration_withdraw), + tt); +} + + +/** + * Create new keys and expire ancient keys of the given denomination @a denom. + * Removes the @a denom from the #denom_head DLL and re-insert its at the + * correct location sorted by next maintenance activity. + * + * @param[in,out] denom denomination to update material for + * @param now current time to use (to get many keys to use the exact same time) + * @param[in,out] wake set to true if we should wake the clients + * @return #GNUNET_OK on success + */ +static enum GNUNET_GenericReturnValue +update_keys (struct Denomination *denom, + struct GNUNET_TIME_Timestamp now, + bool *wake) +{ + /* create new denomination keys */ + if (NULL != denom->keys_tail) + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + "Updating keys of denomination `%s', last key %s valid for another %s\n", + denom->section, + GNUNET_h2s (&denom->keys_tail->h_cs.hash), + GNUNET_TIME_relative2s ( + GNUNET_TIME_absolute_get_remaining ( + GNUNET_TIME_absolute_subtract ( + GNUNET_TIME_absolute_add ( + denom->keys_tail->anchor.abs_time, + denom->duration_withdraw), + overlap_duration)), + GNUNET_YES)); + while ( (NULL == denom->keys_tail) || + GNUNET_TIME_absolute_is_past ( + GNUNET_TIME_absolute_subtract ( + GNUNET_TIME_absolute_subtract ( + GNUNET_TIME_absolute_add (denom->keys_tail->anchor.abs_time, + denom->duration_withdraw), + lookahead_sign), + overlap_duration)) ) + { + if (! *wake) + { + key_gen++; + *wake = true; + } + if (GNUNET_OK != + create_key (denom, + now)) + { + GNUNET_break (0); + global_ret = EXIT_FAILURE; + GNUNET_SCHEDULER_shutdown (); + return GNUNET_SYSERR; + } + } + /* remove expired denomination keys */ + while ( (NULL != denom->keys_head) && + GNUNET_TIME_absolute_is_past + (GNUNET_TIME_absolute_add (denom->keys_head->anchor.abs_time, + denom->duration_withdraw)) ) + { + struct DenominationKey *key = denom->keys_head; + struct DenominationKey *nxt = key->next; + + if (0 != key->rc) + break; /* later */ + GNUNET_CONTAINER_DLL_remove (denom->keys_head, + denom->keys_tail, + key); + GNUNET_assert (GNUNET_OK == + GNUNET_CONTAINER_multihashmap_remove ( + keys, + &key->h_cs.hash, + key)); + if ( (! key->purge) && + (0 != unlink (key->filename)) ) + GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR, + "unlink", + key->filename); + GNUNET_free (key->filename); + GNUNET_CRYPTO_rsa_private_key_free (key->denom_priv); + GNUNET_CRYPTO_rsa_public_key_free (key->denom_pub); + GNUNET_free (key->an); + GNUNET_free (key); + key = nxt; + } + + /* Update position of 'denom' in #denom_head DLL: sort by action time */ + { + struct Denomination *before; + struct GNUNET_TIME_Absolute at; + + at = denomination_action_time (denom); + GNUNET_CONTAINER_DLL_remove (denom_head, + denom_tail, + denom); + before = NULL; + for (struct Denomination *pos = denom_head; + NULL != pos; + pos = pos->next) + { + if (GNUNET_TIME_absolute_cmp (denomination_action_time (pos), >=, at)) + break; + before = pos; + } + GNUNET_CONTAINER_DLL_insert_after (denom_head, + denom_tail, + before, + denom); + } + return GNUNET_OK; +} + + +/** + * Task run periodically to expire keys and/or generate fresh ones. + * + * @param cls NULL + */ +static void +update_denominations (void *cls) +{ + struct Denomination *denom; + struct GNUNET_TIME_Absolute now; + struct GNUNET_TIME_Timestamp t; + bool wake = false; + + (void) cls; + keygen_task = NULL; + now = GNUNET_TIME_absolute_get (); + t = GNUNET_TIME_absolute_to_timestamp (now); + GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, + "Updating denominations ...\n"); + GNUNET_assert (0 == pthread_mutex_lock (&keys_lock)); + do { + denom = denom_head; + if (GNUNET_OK != + update_keys (denom, + t, + &wake)) + return; + } while (denom != denom_head); + GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock)); + GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, + "Updating denominations finished ...\n"); + if (wake) + TES_wake_clients (); + keygen_task = GNUNET_SCHEDULER_add_at (denomination_action_time (denom), + &update_denominations, + NULL); +} + + +/** + * Parse private key of denomination @a denom in @a buf. + * + * @param[out] denom denomination of the key + * @param filename name of the file we are parsing, for logging + * @param buf key material + * @param buf_size number of bytes in @a buf + */ +static void +parse_key (struct Denomination *denom, + const char *filename, + const void *buf, + size_t buf_size) +{ + struct GNUNET_CRYPTO_RsaPrivateKey *priv; + char *anchor_s; + char dummy; + unsigned long long anchor_ll; + struct GNUNET_TIME_Timestamp anchor; + + anchor_s = strrchr (filename, + '/'); + if (NULL == anchor_s) + { + /* File in a directory without '/' in the name, this makes no sense. */ + GNUNET_break (0); + return; + } + anchor_s++; + if (1 != sscanf (anchor_s, + "%llu%c", + &anchor_ll, + &dummy)) + { + /* Filenames in KEYDIR must ONLY be the anchor time in seconds! */ + GNUNET_log (GNUNET_ERROR_TYPE_WARNING, + "Filename `%s' invalid for key file, skipping\n", + filename); + return; + } + anchor.abs_time.abs_value_us + = anchor_ll * GNUNET_TIME_UNIT_SECONDS.rel_value_us; + if (anchor_ll != anchor.abs_time.abs_value_us + / GNUNET_TIME_UNIT_SECONDS.rel_value_us) + { + /* Integer overflow. Bad, invalid filename. */ + GNUNET_log (GNUNET_ERROR_TYPE_WARNING, + "Filename `%s' invalid for key file, skipping\n", + filename); + return; + } + priv = GNUNET_CRYPTO_rsa_private_key_decode (buf, + buf_size); + if (NULL == priv) + { + /* Parser failure. */ + GNUNET_log (GNUNET_ERROR_TYPE_WARNING, + "File `%s' is malformed, skipping\n", + filename); + return; + } + + { + struct GNUNET_CRYPTO_RsaPublicKey *pub; + struct DenominationKey *dk; + struct DenominationKey *before; + + pub = GNUNET_CRYPTO_rsa_private_key_get_public (priv); + if (NULL == pub) + { + GNUNET_break (0); + GNUNET_CRYPTO_rsa_private_key_free (priv); + return; + } + dk = GNUNET_new (struct DenominationKey); + dk->denom_priv = priv; + dk->denom = denom; + dk->anchor = anchor; + dk->filename = GNUNET_strdup (filename); + TALER_rsa_pub_hash (pub, + &dk->h_cs); + dk->denom_pub = pub; + generate_response (dk); + if (GNUNET_OK != + GNUNET_CONTAINER_multihashmap_put ( + keys, + &dk->h_cs.hash, + dk, + GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)) + { + GNUNET_log (GNUNET_ERROR_TYPE_ERROR, + "Duplicate private key %s detected in file `%s'. Skipping.\n", + GNUNET_h2s (&dk->h_cs.hash), + filename); + GNUNET_CRYPTO_rsa_private_key_free (priv); + GNUNET_CRYPTO_rsa_public_key_free (pub); + GNUNET_free (dk->an); + GNUNET_free (dk); + return; + } + before = NULL; + for (struct DenominationKey *pos = denom->keys_head; + NULL != pos; + pos = pos->next) + { + if (GNUNET_TIME_timestamp_cmp (pos->anchor, >, anchor)) + break; + before = pos; + } + GNUNET_CONTAINER_DLL_insert_after (denom->keys_head, + denom->keys_tail, + before, + dk); + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + "Imported key %s from `%s'\n", + GNUNET_h2s (&dk->h_cs.hash), + filename); + } +} + + +/** + * Import a private key from @a filename for the denomination + * given in @a cls. + * + * @param[in,out] cls a `struct Denomiantion` + * @param filename name of a file in the directory + * @return #GNUNET_OK (always, continue to iterate) + */ +static enum GNUNET_GenericReturnValue +import_key (void *cls, + const char *filename) +{ + struct Denomination *denom = cls; + struct GNUNET_DISK_FileHandle *fh; + struct GNUNET_DISK_MapHandle *map; + void *ptr; + int fd; + struct stat sbuf; + + { + struct stat lsbuf; + + if (0 != lstat (filename, + &lsbuf)) + { + GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, + "lstat", + filename); + return GNUNET_OK; + } + if (! S_ISREG (lsbuf.st_mode)) + { + GNUNET_log (GNUNET_ERROR_TYPE_ERROR, + "File `%s' is not a regular file, which is not allowed for private keys!\n", + filename); + return GNUNET_OK; + } + } + + fd = open (filename, + O_CLOEXEC); + if (-1 == fd) + { + GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, + "open", + filename); + GNUNET_break (0 == close (fd)); + return GNUNET_OK; + } + if (0 != fstat (fd, + &sbuf)) + { + GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, + "stat", + filename); + return GNUNET_OK; + } + if (! S_ISREG (sbuf.st_mode)) + { + GNUNET_log (GNUNET_ERROR_TYPE_ERROR, + "File `%s' is not a regular file, which is not allowed for private keys!\n", + filename); + GNUNET_break (0 == close (fd)); + return GNUNET_OK; + } + if (0 != (sbuf.st_mode & (S_IWUSR | S_IRWXG | S_IRWXO))) + { + /* permission are NOT tight, try to patch them up! */ + if (0 != + fchmod (fd, + S_IRUSR)) + { + GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, + "fchmod", + filename); + /* refuse to use key if file has wrong permissions */ + GNUNET_break (0 == close (fd)); + return GNUNET_OK; + } + } + fh = GNUNET_DISK_get_handle_from_int_fd (fd); + if (NULL == fh) + { + GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, + "open", + filename); + GNUNET_break (0 == close (fd)); + return GNUNET_OK; + } + if (sbuf.st_size > 16 * 1024) + { + GNUNET_log (GNUNET_ERROR_TYPE_ERROR, + "File `%s' too big to be a private key\n", + filename); + GNUNET_DISK_file_close (fh); + return GNUNET_OK; + } + ptr = GNUNET_DISK_file_map (fh, + &map, + GNUNET_DISK_MAP_TYPE_READ, + (size_t) sbuf.st_size); + if (NULL == ptr) + { + GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, + "mmap", + filename); + GNUNET_DISK_file_close (fh); + return GNUNET_OK; + } + parse_key (denom, + filename, + ptr, + (size_t) sbuf.st_size); + GNUNET_DISK_file_unmap (map); + GNUNET_DISK_file_close (fh); + return GNUNET_OK; +} + + +/** + * Parse configuration for denomination type parameters. Also determines + * our anchor by looking at the existing denominations of the same type. + * + * @param cfg configuration to use + * @param ct section in the configuration file giving the denomination type parameters + * @param[out] denom set to the denomination parameters from the configuration + * @return #GNUNET_OK on success, #GNUNET_SYSERR if the configuration is invalid + */ +static enum GNUNET_GenericReturnValue +parse_denomination_cfg (const struct GNUNET_CONFIGURATION_Handle *cfg, + const char *ct, + struct Denomination *denom) +{ + unsigned long long rsa_keysize; + + if (GNUNET_OK != + GNUNET_CONFIGURATION_get_value_time (cfg, + ct, + "DURATION_WITHDRAW", + &denom->duration_withdraw)) + { + GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR, + ct, + "DURATION_WITHDRAW"); + return GNUNET_SYSERR; + } + if (GNUNET_TIME_relative_cmp (overlap_duration, + >=, + denom->duration_withdraw)) + { + GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR, + "taler-exchange-secmod-cs", + "OVERLAP_DURATION", + "Value given must be smaller than value for DURATION_WITHDRAW!"); + return GNUNET_SYSERR; + } + if (GNUNET_OK != + GNUNET_CONFIGURATION_get_value_number (cfg, + ct, + "RSA_KEYSIZE", + &rsa_keysize)) + { + GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR, + ct, + "RSA_KEYSIZE"); + return GNUNET_SYSERR; + } + if ( (rsa_keysize > 4 * 2048) || + (rsa_keysize < 1024) ) + { + GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR, + ct, + "RSA_KEYSIZE", + "Given RSA keysize outside of permitted range [1024,8192]\n"); + return GNUNET_SYSERR; + } + denom->rsa_keysize = (unsigned int) rsa_keysize; + denom->section = GNUNET_strdup (ct); + return GNUNET_OK; +} + + +/** + * Closure for #load_denominations. + */ +struct LoadContext +{ + + /** + * Configuration to use. + */ + const struct GNUNET_CONFIGURATION_Handle *cfg; + + /** + * Current time to use. + */ + struct GNUNET_TIME_Timestamp t; + + /** + * Status, to be set to #GNUNET_SYSERR on failure + */ + enum GNUNET_GenericReturnValue ret; +}; + + +/** + * Generate new denomination signing keys for the denomination type of the given @a + * denomination_alias. + * + * @param cls a `struct LoadContext`, with 'ret' to be set to #GNUNET_SYSERR on failure + * @param denomination_alias name of the denomination's section in the configuration + */ +static void +load_denominations (void *cls, + const char *denomination_alias) +{ + struct LoadContext *ctx = cls; + struct Denomination *denom; + bool wake = true; + + if ( (0 != strncasecmp (denomination_alias, + "coin_", + strlen ("coin_"))) && + (0 != strncasecmp (denomination_alias, + "coin-", + strlen ("coin-"))) ) + return; /* not a denomination type definition */ + denom = GNUNET_new (struct Denomination); + if (GNUNET_OK != + parse_denomination_cfg (ctx->cfg, + denomination_alias, + denom)) + { + ctx->ret = GNUNET_SYSERR; + GNUNET_free (denom); + return; + } + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + "Loading keys for denomination %s\n", + denom->section); + { + char *dname; + + GNUNET_asprintf (&dname, + "%s/%s", + keydir, + denom->section); + GNUNET_break (GNUNET_OK == + GNUNET_DISK_directory_create (dname)); + GNUNET_DISK_directory_scan (dname, + &import_key, + denom); + GNUNET_free (dname); + } + GNUNET_CONTAINER_DLL_insert (denom_head, + denom_tail, + denom); + update_keys (denom, + ctx->t, + &wake); +} + + +/** + * Load the various duration values from @a cfg + * + * @param cfg configuration to use + * @return #GNUNET_OK on success + */ +static enum GNUNET_GenericReturnValue +load_durations (const struct GNUNET_CONFIGURATION_Handle *cfg) +{ + if (GNUNET_OK != + GNUNET_CONFIGURATION_get_value_time (cfg, + "taler-exchange-secmod-cs", + "OVERLAP_DURATION", + &overlap_duration)) + { + GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR, + "taler-exchange-secmod-cs", + "OVERLAP_DURATION"); + return GNUNET_SYSERR; + } + if (GNUNET_OK != + GNUNET_CONFIGURATION_get_value_time (cfg, + "taler-exchange-secmod-cs", + "LOOKAHEAD_SIGN", + &lookahead_sign)) + { + GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR, + "taler-exchange-secmod-cs", + "LOOKAHEAD_SIGN"); + return GNUNET_SYSERR; + } + return GNUNET_OK; +} + + +/** + * Function run on shutdown. Stops the various jobs (nicely). + * + * @param cls NULL + */ +static void +do_shutdown (void *cls) +{ + (void) cls; + TES_listen_stop (); + if (NULL != keygen_task) + { + GNUNET_SCHEDULER_cancel (keygen_task); + keygen_task = NULL; + } +} + + +/** + * Main function that will be run under the GNUnet scheduler. + * + * @param cls closure + * @param args remaining command-line arguments + * @param cfgfile name of the configuration file used (for saving, can be NULL!) + * @param cfg configuration + */ +static void +run (void *cls, + char *const *args, + const char *cfgfile, + const struct GNUNET_CONFIGURATION_Handle *cfg) +{ + static struct TES_Callbacks cb = { + .dispatch = cs_work_dispatch, + .updater = cs_update_client_keys, + .init = cs_client_init + }; + + (void) cls; + (void) args; + (void) cfgfile; + if (GNUNET_TIME_timestamp_cmp (now, !=, now_tmp)) + { + /* The user gave "--now", use it! */ + now = now_tmp; + } + else + { + /* get current time again, we may be timetraveling! */ + now = GNUNET_TIME_timestamp_get (); + } + if (GNUNET_OK != + GNUNET_CONFIGURATION_get_value_filename (cfg, + "taler-exchange-secmod-cs", + "KEY_DIR", + &keydir)) + { + GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR, + "taler-exchange-secmod-cs", + "KEY_DIR"); + global_ret = EXIT_NOTCONFIGURED; + return; + } + if (GNUNET_OK != + load_durations (cfg)) + { + global_ret = EXIT_NOTCONFIGURED; + return; + } + global_ret = TES_listen_start (cfg, + "taler-exchange-secmod-cs", + &cb); + if (0 != global_ret) + return; + GNUNET_SCHEDULER_add_shutdown (&do_shutdown, + NULL); + /* Load denominations */ + keys = GNUNET_CONTAINER_multihashmap_create (65536, + GNUNET_YES); + { + struct LoadContext lc = { + .cfg = cfg, + .ret = GNUNET_OK, + .t = now + }; + + GNUNET_assert (0 == pthread_mutex_lock (&keys_lock)); + GNUNET_CONFIGURATION_iterate_sections (cfg, + &load_denominations, + &lc); + GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock)); + if (GNUNET_OK != lc.ret) + { + global_ret = EXIT_FAILURE; + GNUNET_SCHEDULER_shutdown (); + return; + } + } + if (NULL == denom_head) + { + GNUNET_log (GNUNET_ERROR_TYPE_ERROR, + "No denominations configured\n"); + global_ret = EXIT_NOTCONFIGURED; + GNUNET_SCHEDULER_shutdown (); + return; + } + /* start job to keep keys up-to-date; MUST be run before the #listen_task, + hence with priority. */ + keygen_task = GNUNET_SCHEDULER_add_with_priority ( + GNUNET_SCHEDULER_PRIORITY_URGENT, + &update_denominations, + NULL); +} + + +/** + * The entry point. + * + * @param argc number of arguments in @a argv + * @param argv command-line arguments + * @return 0 on normal termination + */ +int +main (int argc, + char **argv) +{ + struct GNUNET_GETOPT_CommandLineOption options[] = { + GNUNET_GETOPT_option_timetravel ('T', + "timetravel"), + GNUNET_GETOPT_option_timestamp ('t', + "time", + "TIMESTAMP", + "pretend it is a different time for the update", + &now_tmp), + GNUNET_GETOPT_OPTION_END + }; + enum GNUNET_GenericReturnValue ret; + + /* Restrict permissions for the key files that we create. */ + (void) umask (S_IWGRP | S_IROTH | S_IWOTH | S_IXOTH); + + /* force linker to link against libtalerutil; if we do + not do this, the linker may "optimize" libtalerutil + away and skip #TALER_OS_init(), which we do need */ + TALER_OS_init (); + now_tmp = now = GNUNET_TIME_timestamp_get (); + ret = GNUNET_PROGRAM_run (argc, argv, + "taler-exchange-secmod-cs", + "Handle private CS key operations for a Taler exchange", + options, + &run, + NULL); + if (GNUNET_NO == ret) + return EXIT_SUCCESS; + if (GNUNET_SYSERR == ret) + return EXIT_INVALIDARGUMENT; + return global_ret; +} |