instance auth: refactor, make it serializable

1 files changed, 70 insertions, 44 deletions

diff --git a/src/backend/taler-merchant-httpd_private-post-instances-ID-auth.c b/src/backend/taler-merchant-httpd_private-post-instances-ID-auth.c
index 93b0f784..17316348 100644
--- a/src/backend/taler-merchant-httpd_private-post-instances-ID-auth.c
+++ b/src/backend/taler-merchant-httpd_private-post-instances-ID-auth.c
@@ -25,6 +25,7 @@
  */
 #include "platform.h"
 #include "taler-merchant-httpd_private-post-instances-ID-auth.h"
+#include "taler-merchant-httpd_helper.h"
 #include <taler/taler_json_lib.h>
 
 
@@ -52,44 +53,13 @@ post_instances_ID_auth (struct TMH_MerchantInstance *mi,
   json_t *jauth = hc->request_body;
 
   {
-    bool auth_ok = false;
-    const char *auth_method = json_string_value (json_object_get (jauth,
-                                                                  "method"));
+    enum GNUNET_GenericReturnValue ret;
 
-    if (NULL == auth_method)
-    {
-      GNUNET_break_op (0);
-    }
-    else if (0 == strcmp (auth_method,
-                          "external"))
-    {
-      auth_token = NULL;
-      auth_ok = true;
-    }
-    else if (0 == strcmp (auth_method,
-                          "token"))
-    {
-      auth_token = json_string_value (json_object_get (jauth,
-                                                       "token"));
-      if (NULL != auth_token)
-      {
-        if (0 == strncasecmp (RFC_8959_PREFIX,
-                              auth_token,
-                              strlen (RFC_8959_PREFIX)))
-          auth_ok = true;
-      }
-      else
-        GNUNET_break_op (0);
-    }
-
-    if (! auth_ok)
-    {
-      GNUNET_break_op (0);
-      return TALER_MHD_reply_with_error (connection,
-                                         MHD_HTTP_BAD_REQUEST,
-                                         TALER_EC_MERCHANT_PRIVATE_POST_INSTANCE_AUTH_BAD_AUTH,
-                                         "bad authentication config");
-    }
+    ret = TMH_check_auth_config (connection,
+                                 jauth,
+                                 &auth_token);
+    if (GNUNET_OK != ret)
+      return (GNUNET_NO == ret) ? MHD_YES : MHD_NO;
   }
 
   if (NULL == auth_token)
@@ -108,6 +78,7 @@ post_instances_ID_auth (struct TMH_MerchantInstance *mi,
                       &ias.auth_hash);
   }
 
+  /* Store the new auth information in the database */
   {
     enum GNUNET_DB_QueryStatus qs;
 
@@ -122,6 +93,55 @@ post_instances_ID_auth (struct TMH_MerchantInstance *mi,
                                            TALER_EC_GENERIC_DB_START_FAILED,
                                            NULL);
       }
+
+      /* Make the authentication update a serializable operation.
+         We first check that the authentication information
+         that the caller's request authenticated with
+         is still up to date.
+         Otherwise, we've detected a conflicting update
+         to the authentication. */
+      {
+        struct TALER_MERCHANTDB_InstanceAuthSettings db_ias;
+        qs = TMH_db->lookup_instance_auth (TMH_db->cls,
+                                           mi->settings.id,
+                                           &db_ias);
+
+        switch (qs)
+        {
+          case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
+            /* Instance got purged. */
+            TMH_db->rollback (TMH_db->cls);
+            return TALER_MHD_reply_with_error (connection,
+                                              MHD_HTTP_UNAUTHORIZED,
+                                              TALER_EC_GENERIC_DB_COMMIT_FAILED,
+                                              NULL);
+          case GNUNET_DB_STATUS_SOFT_ERROR:
+            TMH_db->rollback (TMH_db->cls);
+            goto retry;
+          case GNUNET_DB_STATUS_HARD_ERROR:
+            TMH_db->rollback (TMH_db->cls);
+            return TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_GENERIC_DB_FETCH_FAILED,
+                                             NULL);
+          case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
+            /* Success! */
+            break;
+        }
+
+        if (GNUNET_OK !=
+            TMH_check_auth (hc->auth_token,
+                            &db_ias.auth_salt,
+                            &db_ias.auth_hash))
+        {
+          TMH_db->rollback (TMH_db->cls);
+          return TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_UNAUTHORIZED,
+                                             TALER_EC_MERCHANT_GENERIC_UNAUTHORIZED,
+                                             NULL);
+        }
+      }
+
       qs = TMH_db->update_instance_auth (TMH_db->cls,
                                          mi->settings.id,
                                          &ias);
@@ -129,12 +149,13 @@ post_instances_ID_auth (struct TMH_MerchantInstance *mi,
       {
         GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR == qs);
         TMH_db->rollback (TMH_db->cls);
-        goto retry;
-      }
-      if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT != qs)
-      {
-        GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR == qs);
-        TMH_db->rollback (TMH_db->cls);
+        if (GNUNET_DB_STATUS_HARD_ERROR == qs)
+        {
+          return TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_GENERIC_DB_FETCH_FAILED,
+                                             NULL);
+        }
         goto retry;
       }
       qs = TMH_db->commit (TMH_db->cls);
@@ -156,7 +177,12 @@ retry:
   }
   if (0 == strcmp (mi->settings.id,
                    "default"))
-    GNUNET_free (TMH_default_auth); /* clear after it was manually set */
+  {
+    /* The default auth string should've been
+       cleared with the first request
+       for the default instance. */
+    GNUNET_assert (NULL == TMH_default_auth);
+  }
   return TALER_MHD_reply_static (connection,
                                  MHD_HTTP_NO_CONTENT,
                                  NULL,