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|
/*
This file is part of TALER
Copyright (C) 2020, 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/crypto_helper_denom.c
* @brief utility functions for running out-of-process private key operations
* @author Christian Grothoff
*/
#include "platform.h"
#include "taler_util.h"
#include "taler_signatures.h"
#include "taler-exchange-secmod-rsa.h"
#include <poll.h>
#include "crypto_helper_common.h"
struct TALER_CRYPTO_DenominationHelper
{
/**
* Function to call with updates to available key material.
*/
TALER_CRYPTO_DenominationKeyStatusCallback dkc;
/**
* Closure for @e dkc
*/
void *dkc_cls;
/**
* Socket address of the denomination helper process.
* Used to reconnect if the connection breaks.
*/
struct sockaddr_un sa;
/**
* The UNIX domain socket, -1 if we are currently not connected.
*/
int sock;
/**
* Have we ever been sync'ed?
*/
bool synced;
};
/**
* Disconnect from the helper process. Updates
* @e sock field in @a dh.
*
* @param[in,out] dh handle to tear down connection of
*/
static void
do_disconnect (struct TALER_CRYPTO_DenominationHelper *dh)
{
GNUNET_break (0 == close (dh->sock));
dh->sock = -1;
dh->synced = false;
}
/**
* Try to connect to the helper process. Updates
* @e sock field in @a dh.
*
* @param[in,out] dh handle to establish connection for
* @return #GNUNET_OK on success
*/
static enum GNUNET_GenericReturnValue
try_connect (struct TALER_CRYPTO_DenominationHelper *dh)
{
if (-1 != dh->sock)
return GNUNET_OK;
dh->sock = socket (AF_UNIX,
SOCK_STREAM,
0);
if (-1 == dh->sock)
{
GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
"socket");
return GNUNET_SYSERR;
}
if (0 !=
connect (dh->sock,
(const struct sockaddr *) &dh->sa,
sizeof (dh->sa)))
{
GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
"connect",
dh->sa.sun_path);
do_disconnect (dh);
return GNUNET_SYSERR;
}
return GNUNET_OK;
}
struct TALER_CRYPTO_DenominationHelper *
TALER_CRYPTO_helper_denom_connect (
const struct GNUNET_CONFIGURATION_Handle *cfg,
TALER_CRYPTO_DenominationKeyStatusCallback dkc,
void *dkc_cls)
{
struct TALER_CRYPTO_DenominationHelper *dh;
char *unixpath;
if (GNUNET_OK !=
GNUNET_CONFIGURATION_get_value_filename (cfg,
"taler-exchange-secmod-rsa",
"UNIXPATH",
&unixpath))
{
GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
"taler-exchange-secmod-rsa",
"UNIXPATH");
return NULL;
}
/* we use >= here because we want the sun_path to always
be 0-terminated */
if (strlen (unixpath) >= sizeof (dh->sa.sun_path))
{
GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
"taler-exchange-secmod-rsa",
"UNIXPATH",
"path too long");
GNUNET_free (unixpath);
return NULL;
}
dh = GNUNET_new (struct TALER_CRYPTO_DenominationHelper);
dh->dkc = dkc;
dh->dkc_cls = dkc_cls;
dh->sa.sun_family = AF_UNIX;
strncpy (dh->sa.sun_path,
unixpath,
sizeof (dh->sa.sun_path) - 1);
GNUNET_free (unixpath);
dh->sock = -1;
if (GNUNET_OK !=
try_connect (dh))
{
TALER_CRYPTO_helper_denom_disconnect (dh);
return NULL;
}
TALER_CRYPTO_helper_denom_poll (dh);
return dh;
}
/**
* Handle a #TALER_HELPER_RSA_MT_AVAIL message from the helper.
*
* @param dh helper context
* @param hdr message that we received
* @return #GNUNET_OK on success
*/
static enum GNUNET_GenericReturnValue
handle_mt_avail (struct TALER_CRYPTO_DenominationHelper *dh,
const struct GNUNET_MessageHeader *hdr)
{
const struct TALER_CRYPTO_RsaKeyAvailableNotification *kan
= (const struct TALER_CRYPTO_RsaKeyAvailableNotification *) hdr;
const char *buf = (const char *) &kan[1];
const char *section_name;
if (sizeof (*kan) > ntohs (hdr->size))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
if (ntohs (hdr->size) !=
sizeof (*kan)
+ ntohs (kan->pub_size)
+ ntohs (kan->section_name_len))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
section_name = &buf[ntohs (kan->pub_size)];
if ('\0' != section_name[ntohs (kan->section_name_len) - 1])
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
{
struct TALER_DenominationPublicKey denom_pub;
struct TALER_DenominationHash h_denom_pub;
denom_pub.cipher = TALER_DENOMINATION_RSA;
denom_pub.details.rsa_public_key
= GNUNET_CRYPTO_rsa_public_key_decode (buf,
ntohs (kan->pub_size));
if (NULL == denom_pub.details.rsa_public_key)
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
GNUNET_CRYPTO_rsa_public_key_hash (denom_pub.details.rsa_public_key,
&h_denom_pub.hash);
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Received RSA key %s (%s)\n",
GNUNET_h2s (&h_denom_pub.hash),
section_name);
if (GNUNET_OK !=
TALER_exchange_secmod_denom_verify (
&h_denom_pub,
section_name,
GNUNET_TIME_absolute_ntoh (kan->anchor_time),
GNUNET_TIME_relative_ntoh (kan->duration_withdraw),
&kan->secm_pub,
&kan->secm_sig))
{
GNUNET_break_op (0);
TALER_denom_pub_free (&denom_pub);
return GNUNET_SYSERR;
}
dh->dkc (dh->dkc_cls,
section_name,
GNUNET_TIME_absolute_ntoh (kan->anchor_time),
GNUNET_TIME_relative_ntoh (kan->duration_withdraw),
&h_denom_pub,
&denom_pub,
&kan->secm_pub,
&kan->secm_sig);
TALER_denom_pub_free (&denom_pub);
}
return GNUNET_OK;
}
/**
* Handle a #TALER_HELPER_RSA_MT_PURGE message from the helper.
*
* @param dh helper context
* @param hdr message that we received
* @return #GNUNET_OK on success
*/
static enum GNUNET_GenericReturnValue
handle_mt_purge (struct TALER_CRYPTO_DenominationHelper *dh,
const struct GNUNET_MessageHeader *hdr)
{
const struct TALER_CRYPTO_RsaKeyPurgeNotification *pn
= (const struct TALER_CRYPTO_RsaKeyPurgeNotification *) hdr;
if (sizeof (*pn) != ntohs (hdr->size))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Received revocation of denomination key %s\n",
GNUNET_h2s (&pn->h_denom_pub.hash));
dh->dkc (dh->dkc_cls,
NULL,
GNUNET_TIME_UNIT_ZERO_ABS,
GNUNET_TIME_UNIT_ZERO,
&pn->h_denom_pub,
NULL,
NULL,
NULL);
return GNUNET_OK;
}
void
TALER_CRYPTO_helper_denom_poll (struct TALER_CRYPTO_DenominationHelper *dh)
{
char buf[UINT16_MAX];
size_t off = 0;
unsigned int retry_limit = 3;
const struct GNUNET_MessageHeader *hdr
= (const struct GNUNET_MessageHeader *) buf;
if (GNUNET_OK !=
try_connect (dh))
return; /* give up */
while (1)
{
uint16_t msize;
ssize_t ret;
ret = recv (dh->sock,
buf,
sizeof (buf),
(dh->synced && (0 == off))
? MSG_DONTWAIT
: 0);
if (ret < 0)
{
if (EINTR == errno)
continue;
if (EAGAIN == errno)
{
GNUNET_assert (dh->synced);
GNUNET_assert (0 == off);
break;
}
GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
"recv");
do_disconnect (dh);
if (0 == retry_limit)
return; /* give up */
if (GNUNET_OK !=
try_connect (dh))
return; /* give up */
retry_limit--;
continue;
}
if (0 == ret)
{
GNUNET_break (0 == off);
return;
}
off += ret;
more:
if (off < sizeof (struct GNUNET_MessageHeader))
continue;
msize = ntohs (hdr->size);
if (off < msize)
continue;
switch (ntohs (hdr->type))
{
case TALER_HELPER_RSA_MT_AVAIL:
if (GNUNET_OK !=
handle_mt_avail (dh,
hdr))
{
GNUNET_break_op (0);
do_disconnect (dh);
return;
}
break;
case TALER_HELPER_RSA_MT_PURGE:
if (GNUNET_OK !=
handle_mt_purge (dh,
hdr))
{
GNUNET_break_op (0);
do_disconnect (dh);
return;
}
break;
case TALER_HELPER_RSA_SYNCED:
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Now synchronized with RSA helper\n");
dh->synced = true;
break;
default:
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Received unexpected message of type %d (len: %u)\n",
(unsigned int) ntohs (hdr->type),
(unsigned int) msize);
GNUNET_break_op (0);
do_disconnect (dh);
return;
}
memmove (buf,
&buf[msize],
off - msize);
off -= msize;
goto more;
}
}
struct TALER_BlindedDenominationSignature
TALER_CRYPTO_helper_denom_sign (
struct TALER_CRYPTO_DenominationHelper *dh,
const struct TALER_DenominationHash *h_denom_pub,
const void *msg,
size_t msg_size,
enum TALER_ErrorCode *ec)
{
struct TALER_BlindedDenominationSignature ds = {
.cipher = TALER_DENOMINATION_INVALID
};
if (GNUNET_OK !=
try_connect (dh))
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"Failed to connect to helper\n");
*ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_UNAVAILABLE;
return ds;
}
{
char buf[sizeof (struct TALER_CRYPTO_SignRequest) + msg_size];
struct TALER_CRYPTO_SignRequest *sr
= (struct TALER_CRYPTO_SignRequest *) buf;
sr->header.size = htons (sizeof (buf));
sr->header.type = htons (TALER_HELPER_RSA_MT_REQ_SIGN);
sr->reserved = htonl (0);
sr->h_denom_pub = *h_denom_pub;
memcpy (&sr[1],
msg,
msg_size);
if (GNUNET_OK !=
TALER_crypto_helper_send_all (dh->sock,
buf,
sizeof (buf)))
{
GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
"send");
do_disconnect (dh);
*ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_UNAVAILABLE;
return ds;
}
}
{
char buf[UINT16_MAX];
size_t off = 0;
const struct GNUNET_MessageHeader *hdr
= (const struct GNUNET_MessageHeader *) buf;
bool finished = false;
*ec = TALER_EC_INVALID;
while (1)
{
uint16_t msize;
ssize_t ret;
ret = recv (dh->sock,
buf,
sizeof (buf),
(finished && (0 == off))
? MSG_DONTWAIT
: 0);
if (ret < 0)
{
if (EINTR == errno)
continue;
if (EAGAIN == errno)
{
GNUNET_assert (finished);
GNUNET_assert (0 == off);
return ds;
}
GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
"recv");
do_disconnect (dh);
*ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_UNAVAILABLE;
break;
}
if (0 == ret)
{
GNUNET_break (0 == off);
if (! finished)
*ec = TALER_EC_EXCHANGE_SIGNKEY_HELPER_BUG;
return ds;
}
off += ret;
more:
if (off < sizeof (struct GNUNET_MessageHeader))
continue;
msize = ntohs (hdr->size);
if (off < msize)
continue;
switch (ntohs (hdr->type))
{
case TALER_HELPER_RSA_MT_RES_SIGNATURE:
if ( (msize < sizeof (struct TALER_CRYPTO_SignResponse)) ||
(finished) )
{
GNUNET_break_op (0);
do_disconnect (dh);
*ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_BUG;
goto end;
}
{
const struct TALER_CRYPTO_SignResponse *sr =
(const struct TALER_CRYPTO_SignResponse *) buf;
struct GNUNET_CRYPTO_RsaSignature *rsa_signature;
rsa_signature = GNUNET_CRYPTO_rsa_signature_decode (
&sr[1],
msize - sizeof (*sr));
if (NULL == rsa_signature)
{
GNUNET_break_op (0);
do_disconnect (dh);
*ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_BUG;
goto end;
}
*ec = TALER_EC_NONE;
finished = true;
ds.details.blinded_rsa_signature = rsa_signature;
break;
}
case TALER_HELPER_RSA_MT_RES_SIGN_FAILURE:
if (msize != sizeof (struct TALER_CRYPTO_SignFailure))
{
GNUNET_break_op (0);
do_disconnect (dh);
*ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_BUG;
goto end;
}
{
const struct TALER_CRYPTO_SignFailure *sf =
(const struct TALER_CRYPTO_SignFailure *) buf;
*ec = (enum TALER_ErrorCode) ntohl (sf->ec);
return ds;
}
case TALER_HELPER_RSA_MT_AVAIL:
if (GNUNET_OK !=
handle_mt_avail (dh,
hdr))
{
GNUNET_break_op (0);
do_disconnect (dh);
*ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_BUG;
goto end;
}
break; /* while(1) loop ensures we recvfrom() again */
case TALER_HELPER_RSA_MT_PURGE:
if (GNUNET_OK !=
handle_mt_purge (dh,
hdr))
{
GNUNET_break_op (0);
do_disconnect (dh);
*ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_BUG;
goto end;
}
break; /* while(1) loop ensures we recvfrom() again */
case TALER_HELPER_RSA_SYNCED:
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"Synchronized add odd time with RSA helper!\n");
dh->synced = true;
break;
default:
GNUNET_break_op (0);
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Received unexpected message of type %u\n",
ntohs (hdr->type));
do_disconnect (dh);
*ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_BUG;
goto end;
}
memmove (buf,
&buf[msize],
off - msize);
off -= msize;
goto more;
} /* while(1) */
end:
if (finished)
TALER_blinded_denom_sig_free (&ds);
return ds;
}
}
void
TALER_CRYPTO_helper_denom_revoke (
struct TALER_CRYPTO_DenominationHelper *dh,
const struct TALER_DenominationHash *h_denom_pub)
{
struct TALER_CRYPTO_RevokeRequest rr = {
.header.size = htons (sizeof (rr)),
.header.type = htons (TALER_HELPER_RSA_MT_REQ_REVOKE),
.h_denom_pub = *h_denom_pub
};
if (GNUNET_OK !=
try_connect (dh))
return; /* give up */
if (GNUNET_OK !=
TALER_crypto_helper_send_all (dh->sock,
&rr,
sizeof (rr)))
{
GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
"send");
do_disconnect (dh);
return;
}
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Requested revocation of denomination key %s\n",
GNUNET_h2s (&h_denom_pub->hash));
}
void
TALER_CRYPTO_helper_denom_disconnect (
struct TALER_CRYPTO_DenominationHelper *dh)
{
if (-1 != dh->sock)
do_disconnect (dh);
GNUNET_free (dh);
}
/* end of crypto_helper_denom.c */
|