1 files changed, 588 insertions, 0 deletions
diff --git a/src/util/crypto_helper_denom.c b/src/util/crypto_helper_denom.c
new file mode 100644
index 000000000..b999be02a
--- /dev/null
+++ b/src/util/crypto_helper_denom.c
@@ -0,0 +1,588 @@
+/*
+  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_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-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;
+
+  /**
+   * Socket address of this process.
+   */
+  struct sockaddr_un my_sa;
+
+  /**
+   * Template for @e my_sa.
+   */
+  char *template;
+
+  /**
+   * 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));
+  if (0 != unlink (dh->my_sa.sun_path))
+    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
+                              "unlink",
+                              dh->my_sa.sun_path);
+  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;
+  }
+  {
+    char *tmpdir;
+
+    tmpdir = GNUNET_DISK_mktemp (dh->template);
+    if (NULL == tmpdir)
+    {
+      do_disconnect (dh);
+      return;
+    }
+    /* we use >= here because we want the sun_path to always
+       be 0-terminated */
+    if (strlen (tmpdir) >= sizeof (dh->sa.sun_path))
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                                 "PATHS",
+                                 "TALER_RUNTIME_DIR",
+                                 "path too long");
+      GNUNET_free (tmpdir);
+      do_disconnect (dh);
+      return;
+    }
+    dh->my_sa.sun_family = AF_UNIX;
+    strncpy (dh->my_sa.sun_path,
+             tmpdir,
+             sizeof (dh->sa.sun_path));
+    if (0 != unlink (tmpdir))
+      GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
+                                "unlink",
+                                tmpdir);
+    GNUNET_free (tmpdir);
+  }
+  if (0 != bind (dh->sock,
+                 (const struct sockaddr *) &dh->my_sa,
+                 sizeof (dh->my_sa)))
+  {
+    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
+                         "bind");
+    do_disconnect (dh);
+    return;
+  }
+  {
+    struct GNUNET_MessageHeader hdr = {
+      .size = htons (sizeof (hdr)),
+      .type = htons (TALER_HELPER_RSA_MT_REQ_INIT)
+    };
+    ssize_t ret;
+
+    ret = sendto (dh->sock,
+                  &hdr,
+                  sizeof (hdr),
+                  0,
+                  (const struct sockaddr *) &dh->sa,
+                  sizeof (dh->sa));
+    if (ret < 0)
+    {
+      GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
+                                "sendto",
+                                dh->sa.sun_path);
+      do_disconnect (dh);
+      return;
+    }
+    /* We are using SOCK_DGRAM, partial writes should not be possible */
+    GNUNET_break (((size_t) ret) == sizeof (hdr));
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Successfully sent REQ_INIT\n");
+  }
+
+}
+
+
+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;
+  }
+  /* 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-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;
+  dh->sa.sun_family = AF_UNIX;
+  strncpy (dh->sa.sun_path,
+           unixpath,
+           sizeof (dh->sa.sun_path));
+  dh->sock = -1;
+  {
+    char *tmpdir;
+    char *template;
+
+    if (GNUNET_OK !=
+        GNUNET_CONFIGURATION_get_value_filename (cfg,
+                                                 "PATHS",
+                                                 "TALER_RUNTIME_DIR",
+                                                 &tmpdir))
+    {
+      GNUNET_log_config_missing (GNUNET_ERROR_TYPE_WARNING,
+                                 "PATHS",
+                                 "TALER_RUNTIME_DIR");
+      tmpdir = GNUNET_strdup ("/tmp");
+    }
+    GNUNET_asprintf (&template,
+                     "%s/crypto-rsa-client/XXXXXX",
+                     tmpdir);
+    GNUNET_free (tmpdir);
+    if (GNUNET_OK !=
+        GNUNET_DISK_directory_create_for_file (template))
+    {
+      GNUNET_free (dh);
+      GNUNET_free (template);
+      return NULL;
+    }
+    dh->template = template;
+  }
+  TALER_CRYPTO_helper_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 int
+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 GNUNET_HashCode h_denom_pub;
+
+    denom_pub.rsa_public_key
+      = GNUNET_CRYPTO_rsa_public_key_decode (buf,
+                                             ntohs (kan->pub_size));
+    if (NULL == denom_pub.rsa_public_key)
+    {
+      GNUNET_break_op (0);
+      return GNUNET_SYSERR;
+    }
+    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);
+  }
+  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 int
+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;
+  }
+  dh->dkc (dh->dkc_cls,
+           NULL,
+           GNUNET_TIME_UNIT_ZERO_ABS,
+           GNUNET_TIME_UNIT_ZERO,
+           &pn->h_denom_pub,
+           NULL);
+  return GNUNET_OK;
+}
+
+
+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)
+    {
+      if (EAGAIN == errno)
+        break;
+      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:
+      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;
+    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 = sendto (dh->sock,
+                  buf,
+                  sizeof (buf),
+                  0,
+                  &dh->sa,
+                  sizeof (dh->sa));
+    if (ret < 0)
+    {
+      GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
+                           "sendto");
+      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));
+  }
+
+  while (1)
+  {
+    char buf[UINT16_MAX];
+    ssize_t ret;
+    const struct GNUNET_MessageHeader *hdr
+      = (const struct GNUNET_MessageHeader *) buf;
+
+    ret = recv (dh->sock,
+                buf,
+                sizeof (buf),
+                0);
+    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;
+        return ds;
+      }
+      {
+        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;
+          return ds;
+        }
+        *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;
+        return ds;
+      }
+      {
+        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;
+        return ds;
+      }
+      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;
+        return ds;
+      }
+      break; /* while(1) loop ensures we recvfrom() again */
+    default:
+      GNUNET_break_op (0);
+      do_disconnect (dh);
+      *ec = TALER_EC_EXCHANGE_DENOMINATION_HELPER_BUG;
+      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 = sendto (dh->sock,
+                &rr,
+                sizeof (rr),
+                0,
+                (const struct sockaddr *) &dh->sa,
+                sizeof (dh->sa));
+  if (ret < 0)
+  {
+    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
+                         "sendto");
+    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->template);
+  GNUNET_free (dh);
+}
+
+
+/* end of crypto_helper_denom.c */