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authorChristian Grothoff <christian@grothoff.org>2020-11-21 23:58:00 +0100
committerChristian Grothoff <christian@grothoff.org>2020-11-21 23:58:00 +0100
commit9b68dbb8e6c873ff40c00da85b3a9f709afd42e1 (patch)
tree32006db3b17e98c0c738641c0624072a6a83203a
parent5fb918ae7ea8215a2b32b08308b8921d8aca74bf (diff)
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implementing client library for talking to the crypto helper process
m---------contrib/gana0
-rw-r--r--src/include/taler_crypto_lib.h119
-rw-r--r--src/util/Makefile.am1
-rw-r--r--src/util/crypto_helper.c406
-rw-r--r--src/util/taler-helper-crypto-rsa.h4
5 files changed, 527 insertions, 3 deletions
diff --git a/contrib/gana b/contrib/gana
-Subproject 05da9c93fc7fff258e54a9413d11ea72a82fe03
+Subproject e5ae01eeb4dedd8599473e64e098ea97fb7dadd
diff --git a/src/include/taler_crypto_lib.h b/src/include/taler_crypto_lib.h
index a4fde80b3..e09051049 100644
--- a/src/include/taler_crypto_lib.h
+++ b/src/include/taler_crypto_lib.h
@@ -24,7 +24,7 @@
#include <gnunet/gnunet_util_lib.h>
#include "taler_util.h"
-
+#include "taler_error_codes.h"
#include <gcrypt.h>
@@ -737,6 +737,123 @@ TALER_refresh_get_commitment (struct TALER_RefreshCommitmentP *rc,
const struct TALER_CoinSpendPublicKeyP *coin_pub,
const struct TALER_Amount *amount_with_fee);
+/* **************** Helper-based RSA operations **************** */
+
+/**
+ * Handle for talking to an Denomination key signing helper.
+ */
+struct TALER_CRYPTO_DenominationHelper;
+
+/**
+ * Function called with information about available keys for signing. Usually
+ * only called once per key upon connect. Also called again in case a key is
+ * being revoked, in that case with an @a end_time of zero.
+ *
+ * @param cls closure
+ * @param section_name name of the denomination type in the configuration;
+ * NULL if the key has been revoked or purged
+ * @param start_time when does the key become available for signing;
+ * zero if the key has been revoked or purged
+ * @param validity_duration how long does the key remain available for signing;
+ * zero if the key has been revoked or purged
+ * @param h_denom_pub hash of the @a denom_pub that is available (or was purged)
+ * @param denom_pub the public key itself, NULL if the key was revoked or purged
+ */
+typedef void
+(*TALER_CRYPTO_DenominationKeyStatusCallback)(
+ void *cls,
+ const char *section_name,
+ struct GNUNET_TIME_Absolute start_time,
+ struct GNUNET_TIME_Relative validity_duration,
+ const struct GNUNET_HashCode *h_denom_pub,
+ const struct TALER_DenominationPublicKey *denom_pub);
+
+
+/**
+ * Initiate connection to an denomination key helper.
+ *
+ * @param cfg configuration to use
+ * @param dkc function to call with key information
+ * @param dkc_cls closure for @a dkc
+ * @return NULL on error (such as bad @a cfg).
+ */
+struct TALER_CRYPTO_DenominationHelper *
+TALER_CRYPTO_helper_denom_connect (
+ const struct GNUNET_CONFIGURATION_Handle *cfg,
+ TALER_CRYPTO_DenominationKeyStatusCallback dkc,
+ void *dkc_cls);
+
+
+/**
+ * Function to call to 'poll' for updates to the available key material.
+ * Should be called whenever it is important that the key material status is
+ * current, like when handling a "/keys" request. This function basically
+ * briefly checks if there are messages from the helper announcing changes to
+ * denomination keys.
+ *
+ * @param dh helper process connection
+ */
+void
+TALER_CRYPTO_helper_poll (struct TALER_CRYPTO_DenominationHelper *dh);
+
+
+/**
+ * Request helper @a dh to sign @a msg using the public key corresponding to
+ * @a h_denom_pub.
+ *
+ * This operation will block until the signature has been obtained. Should
+ * this process receive a signal (that is not ignored) while the operation is
+ * pending, the operation will fail. Note that the helper may still believe
+ * that it created the signature. Thus, signals may result in a small
+ * differences in the signature counters. Retrying in this case may work.
+ *
+ * @param dh helper process connection
+ * @param h_denom_pub hash of the public key to use to sign
+ * @param msg message to sign
+ * @param msg_size number of bytes in @a msg
+ * @param[out] ec set to the error code (or #TALER_EC_NONE on success)
+ * @return signature, the value inside the structure will be NULL on failure,
+ * see @a ec for details about the failure
+ */
+struct TALER_DenominationSignature
+TALER_CRYPTO_helper_denom_sign (
+ struct TALER_CRYPTO_DenominationHelper *dh,
+ const struct GNUNET_HashCode *h_denom_pub,
+ const void *msg,
+ size_t msg_size,
+ enum TALER_ErrorCode *ec);
+
+
+/**
+ * Ask the helper to revoke the public key associated with @param h_denom_pub.
+ * Will cause the helper to tell all clients that the key is now unavailable,
+ * and to create a replacement key.
+ *
+ * This operation will block until the revocation request has been
+ * transmitted. Should this process receive a signal (that is not ignored)
+ * while the operation is pending, the operation may fail. If the key is
+ * unknown, this function will also appear to have succeeded. To be sure that
+ * the revocation worked, clients must watch the denomination key status
+ * callback.
+ *
+ * @param dh helper to process connection
+ * @param h_denom_pub hash of the public key to revoke
+ */
+void
+TALER_CRYPTO_helper_denom_revoke (
+ struct TALER_CRYPTO_DenominationHelper *dh,
+ const struct GNUNET_HashCode *h_denom_pub);
+
+
+/**
+ * Close connection to @a dh.
+ *
+ * @param[in] dh connection to close
+ */
+void
+TALER_CRYPTO_helper_denom_disconnect (
+ struct TALER_CRYPTO_DenominationHelper *dh);
+
/* **************** /wire account offline signing **************** */
diff --git a/src/util/Makefile.am b/src/util/Makefile.am
index 4aef4cac7..c74fe2101 100644
--- a/src/util/Makefile.am
+++ b/src/util/Makefile.am
@@ -50,6 +50,7 @@ libtalerutil_la_SOURCES = \
amount.c \
config.c \
crypto.c \
+ crypto_helper.c \
crypto_wire.c \
getopt.c \
lang.c \
diff --git a/src/util/crypto_helper.c b/src/util/crypto_helper.c
new file mode 100644
index 000000000..2b0fbe468
--- /dev/null
+++ b/src/util/crypto_helper.c
@@ -0,0 +1,406 @@
+/*
+ This file is part of TALER
+ Copyright (C) 2020 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.c
+ * @brief utility functions for running out-of-process private key operations
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "taler_util.h"
+#include "taler-helper-crypto-rsa.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;
+};
+
+
+/**
+ * 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;
+}
+
+
+/**
+ * Try to connect to the helper process. Updates
+ * @e sock field in @a dh.
+ *
+ * @param[in,out] dh handle to establish connection for
+ */
+static void
+try_connect (struct TALER_CRYPTO_DenominationHelper *dh)
+{
+ if (-1 != dh->sock)
+ return;
+ dh->sock = socket (AF_UNIX,
+ SOCK_DGRAM,
+ 0);
+ if (-1 == dh->sock)
+ {
+ GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
+ "socket");
+ return;
+ }
+ if (0 != connect (dh->sock,
+ (const struct sockaddr *) &dh->sa,
+ sizeof (dh->sa)))
+ {
+ if (EINPROGRESS != dh->sock)
+ {
+ GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
+ "connect");
+ do_disconnect (dh);
+ return;
+ }
+ }
+}
+
+
+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-helper-crypto-rsa",
+ "UNIXPATH",
+ &unixpath))
+ {
+ GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
+ "taler-helper-crypto-rsa",
+ "UNIXPATH");
+ return NULL;
+ }
+ if (strlen (unixpath) > sizeof (dh->sa.sun_path))
+ {
+ GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+ "taler-helper-crypto-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;
+ strncpy (dh->sa.sun_path,
+ unixpath,
+ sizeof (dh->sa.sun_path));
+ dh->sock = -1;
+ TALER_CRYPTO_helper_poll (dh);
+ return dh;
+}
+
+
+void
+TALER_CRYPTO_helper_poll (struct TALER_CRYPTO_DenominationHelper *dh)
+{
+ char buf[UINT16_MAX];
+ ssize_t ret;
+ const struct GNUNET_MessageHeader *hdr
+ = (const struct GNUNET_MessageHeader *) buf;
+
+ try_connect (dh);
+ if (-1 == dh->sock)
+ return; /* give up */
+ while (1)
+ {
+ ret = recv (dh->sock,
+ buf,
+ sizeof (buf),
+ MSG_DONTWAIT);
+ if (ret < 0)
+ {
+ GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
+ "recv");
+ do_disconnect (dh);
+ return;
+ }
+
+ if ( (ret < sizeof (struct GNUNET_MessageHeader)) ||
+ (ret != ntohs (hdr->size)) )
+ {
+ GNUNET_break_op (0);
+ do_disconnect (dh);
+ return;
+ }
+ switch (ntohs (hdr->type))
+ {
+ case TALER_HELPER_RSA_MT_AVAIL:
+ {
+ const struct TALER_CRYPTO_RsaKeyAvailableNotification *kan
+ = (const struct TALER_CRYPTO_RsaKeyAvailableNotification *) buf;
+ const char *section_name;
+ struct TALER_DenominationPublicKey denom_pub;
+ struct GNUNET_HashCode h_denom_pub;
+
+ if ( (sizeof (*kan) < ret) ||
+ (sizeof (*kan) + ntohs (kan->pub_size) + ntohs (
+ kan->section_name_len)) ||
+ ('\0' != buf[ret - 1]) )
+ {
+ GNUNET_break_op (0);
+ do_disconnect (dh);
+ return;
+ }
+ denom_pub.rsa_public_key
+ = GNUNET_CRYPTO_rsa_public_key_decode (&buf[sizeof (*kan)],
+ ntohs (kan->pub_size));
+ if (NULL == denom_pub.rsa_public_key)
+ {
+ GNUNET_break_op (0);
+ do_disconnect (dh);
+ return;
+ }
+ section_name = &buf[sizeof (*kan) + ntohs (kan->pub_size)];
+ GNUNET_CRYPTO_rsa_public_key_hash (denom_pub.rsa_public_key,
+ &h_denom_pub);
+ 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);
+ GNUNET_CRYPTO_rsa_public_key_free (denom_pub.rsa_public_key);
+ }
+ break;
+ case TALER_HELPER_RSA_MT_PURGE:
+ {
+ const struct TALER_CRYPTO_RsaKeyPurgeNotification *pn
+ = (const struct TALER_CRYPTO_RsaKeyPurgeNotification *) buf;
+
+ if (sizeof (*pn) != ret)
+ {
+ GNUNET_break_op (0);
+ do_disconnect (dh);
+ return;
+ }
+
+ dh->dkc (dh->dkc_cls,
+ NULL,
+ GNUNET_TIME_UNIT_ZERO_ABS,
+ GNUNET_TIME_UNIT_ZERO,
+ &pn->h_denom_pub,
+ NULL);
+ }
+ break;
+ default:
+ GNUNET_break_op (0);
+ do_disconnect (dh);
+ return;
+ }
+ }
+}
+
+
+struct TALER_DenominationSignature
+TALER_CRYPTO_helper_denom_sign (
+ struct TALER_CRYPTO_DenominationHelper *dh,
+ const struct GNUNET_HashCode *h_denom_pub,
+ const void *msg,
+ size_t msg_size,
+ enum TALER_ErrorCode *ec)
+{
+ struct TALER_DenominationSignature ds = { NULL };
+ {
+ char buf[sizeof (struct TALER_CRYPTO_SignRequest) + msg_size];
+ struct TALER_CRYPTO_SignRequest *sr
+ = (struct TALER_CRYPTO_SignRequest *) buf;
+ ssize_t ret;
+
+ try_connect (dh);
+ if (-1 == dh->sock)
+ {
+ *ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_UNAVAILABLE;
+ return ds;
+ }
+ 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);
+ ret = send (dh->sock,
+ buf,
+ sizeof (buf),
+ 0);
+ if (ret < 0)
+ {
+ GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
+ "send");
+ do_disconnect (dh);
+ *ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_UNAVAILABLE;
+ return ds;
+ }
+ /* We are using SOCK_DGRAM, partial writes should not be possible */
+ GNUNET_break (((size_t) ret) == sizeof (buf));
+ }
+
+ {
+ char buf[UINT16_MAX];
+ ssize_t ret;
+ const struct GNUNET_MessageHeader *hdr
+ = (const struct GNUNET_MessageHeader *) buf;
+
+ ret = recv (dh->sock,
+ buf,
+ sizeof (buf),
+ MSG_DONTWAIT);
+ if (ret < 0)
+ {
+ GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
+ "recv");
+ do_disconnect (dh);
+ *ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_UNAVAILABLE;
+ return ds;
+ }
+ if ( (ret < sizeof (struct GNUNET_MessageHeader)) ||
+ (ret != ntohs (hdr->size)) )
+ {
+ GNUNET_break_op (0);
+ do_disconnect (dh);
+ *ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_BUG;
+ return ds;
+ }
+ switch (ntohs (hdr->type))
+ {
+ case TALER_HELPER_RSA_MT_RES_SIGNATURE:
+ if (ret < sizeof (struct TALER_CRYPTO_SignResponse))
+ {
+ GNUNET_break_op (0);
+ do_disconnect (dh);
+ *ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_BUG;
+ break;
+ }
+ {
+ 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],
+ ret - sizeof (*sr));
+ if (NULL == rsa_signature)
+ {
+ GNUNET_break_op (0);
+ do_disconnect (dh);
+ *ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_BUG;
+ break;
+ }
+ *ec = TALER_EC_NONE;
+ ds.rsa_signature = rsa_signature;
+ return ds;
+ }
+ case TALER_HELPER_RSA_MT_RES_SIGN_FAILURE:
+ if (ret != sizeof (struct TALER_CRYPTO_SignFailure))
+ {
+ GNUNET_break_op (0);
+ do_disconnect (dh);
+ *ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_BUG;
+ break;
+ }
+ {
+ const struct TALER_CRYPTO_SignFailure *sf =
+ (const struct TALER_CRYPTO_SignFailure *) buf;
+
+ *ec = (enum TALER_ErrorCode) ntohl (sf->ec);
+ break;
+ }
+ default:
+ GNUNET_break_op (0);
+ do_disconnect (dh);
+ *ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_BUG;
+ break;
+ }
+ }
+ return ds;
+}
+
+
+void
+TALER_CRYPTO_helper_denom_revoke (
+ struct TALER_CRYPTO_DenominationHelper *dh,
+ const struct GNUNET_HashCode *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
+ };
+ ssize_t ret;
+
+ try_connect (dh);
+ if (-1 == dh->sock)
+ return; /* give up */
+ ret = send (dh->sock,
+ &rr,
+ sizeof (rr),
+ 0);
+ if (ret < 0)
+ {
+ GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
+ "send");
+ do_disconnect (dh);
+ return;
+ }
+ /* We are using SOCK_DGRAM, partial writes should not be possible */
+ GNUNET_break (((size_t) ret) == sizeof (rr));
+}
+
+
+void
+TALER_CRYPTO_helper_denom_disconnect (
+ struct TALER_CRYPTO_DenominationHelper *dh)
+{
+ do_disconnect (dh);
+ GNUNET_free (dh);
+}
+
+
+/* end of crypto_helper.c */
diff --git a/src/util/taler-helper-crypto-rsa.h b/src/util/taler-helper-crypto-rsa.h
index 373cd5ea8..a80c32e67 100644
--- a/src/util/taler-helper-crypto-rsa.h
+++ b/src/util/taler-helper-crypto-rsa.h
@@ -99,7 +99,7 @@ struct TALER_CRYPTO_RsaKeyPurgeNotification
struct TALER_CRYPTO_SignRequest
{
/**
- * Type is #TALER_HELPER_RSA_MT_SIGN.
+ * Type is #TALER_HELPER_RSA_MT_REQ_SIGN.
*/
struct GNUNET_MessageHeader header;
@@ -123,7 +123,7 @@ struct TALER_CRYPTO_SignRequest
struct TALER_CRYPTO_RevokeRequest
{
/**
- * Type is #TALER_HELPER_RSA_MT_REVOKE.
+ * Type is #TALER_HELPER_RSA_MT_REQ_REVOKE.
*/
struct GNUNET_MessageHeader header;