1 files changed, 364 insertions, 0 deletions
diff --git a/src/reclaim/pabc_helper.c b/src/reclaim/pabc_helper.c
new file mode 100644
index 000000000..1b1dbea0f
--- /dev/null
+++ b/src/reclaim/pabc_helper.c
@@ -0,0 +1,364 @@
+// maximilian.kaul@aisec.fraunhofer.de
+
+// WIP implementation of
+// https://github.com/ontio/ontology-crypto/wiki/Anonymous-Credential
+// using the relic library https://github.com/relic-toolkit/relic/
+
+#include "pabc_helper.h"
+#include <pwd.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static char pabc_dir[PATH_MAX + 1];
+
+static const char *
+get_homedir ()
+{
+  const char *homedir;
+  if ((homedir = getenv ("HOME")) == NULL)
+  {
+    homedir = getpwuid (getuid ())->pw_dir;
+  }
+  return homedir;
+}
+
+
+static enum GNUNET_GenericReturnValue
+write_file (char const *const filename, const char *buffer)
+{
+  struct GNUNET_DISK_FileHandle *fh;
+  fh = GNUNET_DISK_file_open (filename,
+                              GNUNET_DISK_OPEN_WRITE
+                              | GNUNET_DISK_OPEN_TRUNCATE
+                              | GNUNET_DISK_OPEN_CREATE,
+                              GNUNET_DISK_PERM_USER_WRITE
+                              | GNUNET_DISK_PERM_USER_READ);
+  if (fh == NULL)
+    return GNUNET_SYSERR;
+  if (GNUNET_SYSERR == GNUNET_DISK_file_write (fh,
+                                               buffer, strlen (buffer) + 1))
+    goto fail;
+  GNUNET_DISK_file_close (fh);
+  return GNUNET_OK;
+
+fail:
+  GNUNET_DISK_file_close (fh);
+  return GNUNET_SYSERR;
+}
+
+
+static enum GNUNET_GenericReturnValue
+init_pabc_dir ()
+{
+  size_t filename_size = strlen (get_homedir ()) + 1 + strlen (".local") + 1
+                         + strlen ("pabc-reclaim") + 1;
+  snprintf (pabc_dir, filename_size, "%s/%s/%s",
+            get_homedir (), ".local", "pabc-reclaim");
+  return GNUNET_DISK_directory_create (pabc_dir);
+}
+
+
+static const char *
+get_pabcdir ()
+{
+  init_pabc_dir ();
+  return pabc_dir;
+}
+
+
+enum GNUNET_GenericReturnValue
+read_file (char const *const filename, char **buffer)
+{
+  struct GNUNET_DISK_FileHandle *fh;
+  if (GNUNET_YES != GNUNET_DISK_file_test (filename))
+    return GNUNET_SYSERR;
+
+  fh = GNUNET_DISK_file_open (filename,
+                              GNUNET_DISK_OPEN_READ,
+                              GNUNET_DISK_PERM_USER_READ);
+  if (fh == NULL)
+    return GNUNET_SYSERR;
+  long lSize = GNUNET_DISK_file_seek (fh, 0, GNUNET_DISK_SEEK_END);
+  if (lSize < 0)
+    goto fail;
+  GNUNET_DISK_file_seek (fh, 0, GNUNET_DISK_SEEK_SET);
+  *buffer = calloc ((size_t) lSize + 1, sizeof(char));
+  if (*buffer == NULL)
+    goto fail;
+
+  // copy the file into the buffer:
+  size_t r = GNUNET_DISK_file_read (fh, *buffer, (size_t) lSize);
+  if (r != (size_t) lSize)
+    goto fail;
+
+  GNUNET_DISK_file_close (fh);
+  return GNUNET_OK;
+
+fail:
+  GNUNET_DISK_file_close (fh);
+  return GNUNET_SYSERR;
+}
+
+
+struct pabc_public_parameters *
+PABC_read_issuer_ppfile (const char *f, struct pabc_context *const ctx)
+{
+  if (NULL == ctx)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "No global context provided\n");
+    return NULL;
+  }
+  struct pabc_public_parameters *pp;
+  char *buffer;
+  int r;
+  r = read_file (f, &buffer);
+  if (GNUNET_OK != r)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Error reading file\n");
+    return NULL;
+  }
+  if (PABC_OK != pabc_decode_and_new_public_parameters (ctx, &pp, buffer))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to decode public parameters\n");
+    PABC_FREE_NULL (buffer);
+    return NULL;
+  }
+  PABC_FREE_NULL (buffer);
+  return pp;
+}
+
+
+enum GNUNET_GenericReturnValue
+PABC_load_public_parameters (struct pabc_context *const ctx,
+                             char const *const pp_name,
+                             struct pabc_public_parameters **pp)
+{
+  char fname[PATH_MAX];
+  char *pp_filename;
+  const char *pdir = get_pabcdir ();
+
+  if (ctx == NULL)
+    return GNUNET_SYSERR;
+  if (pp_name == NULL)
+    return GNUNET_SYSERR;
+
+  GNUNET_STRINGS_urlencode (pp_name, strlen (pp_name), &pp_filename);
+  if (GNUNET_YES != GNUNET_DISK_directory_test (pdir, GNUNET_YES))
+  {
+    GNUNET_free (pp_filename);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Error reading %s\n", pdir);
+    return GNUNET_SYSERR;
+  }
+  snprintf (fname, PATH_MAX, "%s/%s%s", pdir, pp_filename, PABC_PP_EXT);
+  if (GNUNET_YES != GNUNET_DISK_file_test (fname))
+  {
+    GNUNET_free (pp_filename);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Error testing %s\n", fname);
+    return GNUNET_SYSERR;
+  }
+  *pp = PABC_read_issuer_ppfile (fname, ctx);
+  if (*pp)
+    return GNUNET_OK;
+  else
+    return GNUNET_SYSERR;
+}
+
+
+enum GNUNET_GenericReturnValue
+PABC_write_public_parameters (char const *const pp_name,
+                              struct pabc_public_parameters *const pp)
+{
+  char *json;
+  char *filename;
+  char *pp_filename;
+  enum pabc_status status;
+  struct pabc_context *ctx = NULL;
+
+  GNUNET_STRINGS_urlencode (pp_name, strlen (pp_name), &pp_filename);
+  PABC_ASSERT (pabc_new_ctx (&ctx));
+  // store in json file
+  status = pabc_encode_public_parameters (ctx, pp, &json);
+  if (status != PABC_OK)
+  {
+    GNUNET_free (pp_filename);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to encode public parameters.\n");
+    pabc_free_ctx (&ctx);
+    return GNUNET_SYSERR;
+  }
+
+  size_t filename_size =
+    strlen (get_pabcdir ()) + 1 + strlen (pp_filename) + strlen (PABC_PP_EXT)
+    + 1;
+  filename = GNUNET_malloc (filename_size);
+  if (! filename)
+  {
+    GNUNET_free (pp_filename);
+    PABC_FREE_NULL (json);
+    pabc_free_ctx (&ctx);
+    return GNUNET_SYSERR;
+  }
+  snprintf (filename, filename_size, "%s/%s%s", get_pabcdir (), pp_filename,
+            PABC_PP_EXT);
+
+  GNUNET_free (pp_filename);
+  if (GNUNET_OK != write_file (filename, json))
+  {
+    PABC_FREE_NULL (filename);
+    PABC_FREE_NULL (json);
+    pabc_free_ctx (&ctx);
+    return GNUNET_SYSERR;
+  }
+  PABC_FREE_NULL (filename);
+  PABC_FREE_NULL (json);
+  pabc_free_ctx (&ctx);
+  return GNUNET_OK;
+}
+
+
+enum GNUNET_GenericReturnValue
+PABC_write_usr_ctx (char const *const usr_name,
+                    char const *const pp_name,
+                    struct pabc_context const *const ctx,
+                    struct pabc_public_parameters const *const pp,
+                    struct pabc_user_context *const usr_ctx)
+{
+
+  char *pp_filename;
+  char *json = NULL;
+  enum pabc_status status;
+  char *fname = NULL;
+
+  if (NULL == usr_name)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "No issuer given.\n");
+    return GNUNET_SYSERR;
+  }
+  if (NULL == pp_name)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "No user given.\n");
+    return GNUNET_SYSERR;
+  }
+  if (NULL == ctx)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "No context given.\n");
+    return GNUNET_SYSERR;
+  }
+  if (NULL == pp)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "No public parameters given.\n");
+    return GNUNET_SYSERR;
+  }
+  if (NULL == usr_ctx)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "No user context given.\n");
+    return GNUNET_SYSERR;
+  }
+
+  GNUNET_STRINGS_urlencode (pp_name, strlen (pp_name), &pp_filename);
+  status = pabc_encode_user_ctx (ctx, pp, usr_ctx, &json);
+  if (PABC_OK != status)
+  {
+    GNUNET_free (pp_filename);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Failed to encode user context.\n");
+    return status;
+  }
+
+  size_t fname_size = strlen (get_pabcdir ()) + 1 + strlen (usr_name) + 1
+                      + strlen (pp_filename) + strlen (PABC_USR_EXT) + 1;
+  fname = GNUNET_malloc (fname_size);
+
+  snprintf (fname, fname_size, "%s/%s_%s%s", get_pabcdir (), usr_name,
+            pp_filename,
+            PABC_USR_EXT);
+
+  GNUNET_free (pp_filename);
+  if (GNUNET_OK == write_file (fname, json))
+  {
+    GNUNET_free (fname);
+    GNUNET_free (json);
+    return GNUNET_OK;
+  }
+  else
+  {
+    GNUNET_free (fname);
+    GNUNET_free (json);
+    return GNUNET_SYSERR;
+  }
+}
+
+
+enum GNUNET_GenericReturnValue
+PABC_read_usr_ctx (char const *const usr_name,
+                   char const *const pp_name,
+                   struct pabc_context const *const ctx,
+                   struct pabc_public_parameters const *const pp,
+                   struct pabc_user_context **usr_ctx)
+{
+  char *json = NULL;
+  char *pp_filename;
+  enum pabc_status status;
+
+  char *fname = NULL;
+
+  if (NULL == usr_name)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "No issuer given.\n");
+    return GNUNET_SYSERR;
+  }
+  if (NULL == pp_name)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "No user given.\n");
+    return GNUNET_SYSERR;
+  }
+  if (NULL == ctx)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "No context given.\n");
+    return GNUNET_SYSERR;
+  }
+  if (NULL == pp)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "No public parameters given.\n");
+    return GNUNET_SYSERR;
+  }
+  if (NULL == usr_ctx)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "No user context given.\n");
+    return GNUNET_SYSERR;
+  }
+  GNUNET_STRINGS_urlencode (pp_name, strlen (pp_name), &pp_filename);
+
+  size_t fname_size = strlen (get_pabcdir ()) + 1 + strlen (usr_name) + 1
+                      + strlen (pp_filename) + strlen (PABC_USR_EXT) + 1;
+  fname = GNUNET_malloc (fname_size);
+  snprintf (fname, fname_size, "%s/%s_%s%s", get_pabcdir (), usr_name,
+            pp_filename,
+            PABC_USR_EXT);
+  GNUNET_free (pp_filename);
+  if (GNUNET_OK != read_file (fname, &json))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to read `%s'\n", fname);
+    PABC_FREE_NULL (fname);
+    return GNUNET_SYSERR;
+  }
+  GNUNET_free (fname);
+
+  status = pabc_new_user_context (ctx, pp, usr_ctx);
+  if (PABC_OK != status)
+  {
+    GNUNET_free (json);
+    return GNUNET_SYSERR;
+  }
+  status = pabc_decode_user_ctx (ctx, pp, *usr_ctx, json);
+  GNUNET_free (json);
+  if (PABC_OK != status)
+  {
+    pabc_free_user_context (ctx, pp, usr_ctx);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Failed to encode user context.\n");
+    return GNUNET_SYSERR;
+  }
+
+  return GNUNET_OK;
+}