/*
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
*/
/**
* @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
#include
#include
#include "taler_error_codes.h"
#include "taler_signatures.h"
#include "secmod_common.h"
#include
/**
* 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_CsPrivateKey denom_priv;
/**
* The public key of the denomination.
*/
struct GNUNET_CRYPTO_CsPublicKey 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;
};
/**
* 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] dk 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;
void *p;
size_t tlen;
GNUNET_assert (sizeof(dk->denom_pub) < UINT16_MAX);
GNUNET_assert (nlen < UINT16_MAX);
tlen = 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->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);
an->denom_pub = dk->denom_pub;
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,
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;
struct GNUNET_CRYPTO_CsRSecret r[2];
struct TALER_BlindedDenominationCsSignAnswer cs_answer;
struct GNUNET_TIME_Absolute now = GNUNET_TIME_absolute_get ();
bool for_melt;
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);
}
for_melt = (0 != ntohl (sr->for_melt));
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Received request to sign over bytes with key %s\n",
GNUNET_h2s (&sr->h_cs.hash));
GNUNET_assert (dk->rc < UINT_MAX);
dk->rc++;
GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock));
GNUNET_CRYPTO_cs_r_derive (&sr->planchet.nonce.nonce,
for_melt ? "rm" : "rw",
&dk->denom_priv,
r);
cs_answer.b = GNUNET_CRYPTO_cs_sign_derive (&dk->denom_priv,
r,
sr->planchet.c,
&sr->planchet.nonce.nonce,
&cs_answer.s_scalar);
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 == cs_answer)
// {
// 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;
size_t tsize;
enum GNUNET_GenericReturnValue ret;
tsize = sizeof (*sr) + sizeof(cs_answer);
GNUNET_assert (tsize < UINT16_MAX);
sr = GNUNET_malloc (tsize);
sr->header.size = htons (tsize);
sr->header.type = htons (TALER_HELPER_CS_MT_RES_SIGNATURE);
sr->cs_answer = cs_answer;
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_CsPrivateKey priv;
struct GNUNET_CRYPTO_CsPublicKey pub;
GNUNET_CRYPTO_cs_private_key_generate (&priv);
GNUNET_CRYPTO_cs_private_key_get_public (&priv,
&pub);
TALER_cs_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,
&priv,
sizeof(priv),
GNUNET_DISK_PERM_USER_READ))
{
GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
"write",
dk->filename);
return GNUNET_SYSERR;
}
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_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 client request @a rdr 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 rdr the request details
* @return #GNUNET_OK on success
*/
static enum GNUNET_GenericReturnValue
handle_r_derive_request (struct TES_Client *client,
const struct TALER_CRYPTO_CsRDeriveRequest *rdr)
{
struct DenominationKey *dk;
struct TALER_DenominationCSPrivateRPairP r_priv;
struct TALER_DenominationCSPublicRPairP r_pub;
struct GNUNET_TIME_Absolute now = GNUNET_TIME_absolute_get ();
bool for_melt;
GNUNET_assert (0 == pthread_mutex_lock (&keys_lock));
dk = GNUNET_CONTAINER_multihashmap_get (keys,
&rdr->h_cs.hash);
if (NULL == dk)
{
struct TALER_CRYPTO_RDeriveFailure rdf = {
.header.size = htons (sizeof (rdr)),
.header.type = htons (TALER_HELPER_CS_MT_RES_RDERIVE_FAILURE),
.ec = htonl (TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN)
};
GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock));
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"R Derive request failed, denomination key %s unknown\n",
GNUNET_h2s (&rdr->h_cs.hash));
return TES_transmit (client->csock,
&rdf.header);
}
if (GNUNET_TIME_absolute_is_future (dk->anchor.abs_time))
{
/* it is too early */
struct TALER_CRYPTO_RDeriveFailure rdf = {
.header.size = htons (sizeof (rdr)),
.header.type = htons (TALER_HELPER_CS_MT_RES_RDERIVE_FAILURE),
.ec = htonl (TALER_EC_EXCHANGE_DENOMINATION_HELPER_TOO_EARLY)
};
GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock));
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"R Derive request failed, denomination key %s is not yet valid\n",
GNUNET_h2s (&rdr->h_cs.hash));
return TES_transmit (client->csock,
&rdf.header);
}
for_melt = (0 != ntohl (rdr->for_melt));
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Received request to derive R with key %s\n",
GNUNET_h2s (&rdr->h_cs.hash));
GNUNET_assert (dk->rc < UINT_MAX);
dk->rc++;
GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock));
GNUNET_CRYPTO_cs_r_derive (&rdr->nonce.nonce,
for_melt ? "rm" : "rw",
&dk->denom_priv,
r_priv.r);
GNUNET_CRYPTO_cs_r_get_public (&r_priv.r[0],
&r_pub.r_pub[0]);
GNUNET_CRYPTO_cs_r_get_public (&r_priv.r[1],
&r_pub.r_pub[1]);
GNUNET_assert (0 == pthread_mutex_lock (&keys_lock));
GNUNET_assert (dk->rc > 0);
dk->rc--;
GNUNET_assert (0 == pthread_mutex_unlock (&keys_lock));
{
struct TALER_CRYPTO_RDeriveResponse rdr = {
.header.size = htons (sizeof (struct TALER_CRYPTO_RDeriveResponse)),
.header.type = htons (TALER_HELPER_CS_MT_RES_RDERIVE),
.r_pub = r_pub
};
enum GNUNET_GenericReturnValue ret;
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Sending CS Derived R after %s\n",
GNUNET_TIME_relative2s (
GNUNET_TIME_absolute_get_duration (now),
GNUNET_YES));
ret = TES_transmit (client->csock,
&rdr.header);
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Sent CS Derived R after %s\n",
GNUNET_TIME_relative2s (
GNUNET_TIME_absolute_get_duration (now),
GNUNET_YES));
return ret;
}
}
/**
* 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);
case TALER_HELPER_CS_MT_REQ_RDERIVE:
if (msize != sizeof (struct TALER_CRYPTO_CsRDeriveRequest))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
return handle_r_derive_request (client,
(const struct
TALER_CRYPTO_CsRDeriveRequest *) 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_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 priv key material
*/
static void
parse_key (struct Denomination *denom,
const char *filename,
const struct GNUNET_CRYPTO_CsPrivateKey *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;
}
{
struct GNUNET_CRYPTO_CsPublicKey pub;
struct DenominationKey *dk;
struct DenominationKey *before;
GNUNET_CRYPTO_cs_private_key_get_public (priv,
&pub);
dk = GNUNET_new (struct DenominationKey);
dk->denom_priv = *priv;
dk->denom = denom;
dk->anchor = anchor;
dk->filename = GNUNET_strdup (filename);
TALER_cs_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_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 != sizeof(struct GNUNET_CRYPTO_CsPrivateKey))
{
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,
(const struct GNUNET_CRYPTO_CsPrivateKey *) ptr);
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)
{
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;
}
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;
char *cipher;
if ( (0 != strncasecmp (denomination_alias,
"coin_",
strlen ("coin_"))) &&
(0 != strncasecmp (denomination_alias,
"coin-",
strlen ("coin-"))) )
return; /* not a denomination type definition */
if (GNUNET_OK !=
GNUNET_CONFIGURATION_get_value_string (ctx->cfg,
denomination_alias,
"CIPHER",
&cipher))
{
GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
denomination_alias,
"CIPHER");
return;
}
if (0 != strcmp (cipher, "CS"))
{
GNUNET_free (cipher);
return; /* Ignore denominations of other types than CS*/
}
GNUNET_free (cipher);
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_WARNING,
"No CS denominations configured\n");
TES_wake_clients ();
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;
}