e2e: Route decrypted messages back up

Parse the decrypted JSON and route it back up to the room code.

Signed-off-by: Dr. David Alan Gilbert <dave@treblig.org>

3 files changed, 52 insertions, 12 deletions

diff --git a/matrix-e2e.c b/matrix-e2e.c
index cad7d30..c43a360 100644
--- a/matrix-e2e.c
+++ b/matrix-e2e.c
@@ -1139,8 +1139,11 @@ out:
     return;
 }
 
-void matrix_e2e_decrypt_room(PurpleConversation *conv,
-                             struct _JsonObject *cevent)
+/*
+ * If succesful returns a JsonParser on the decrypted event.
+ */
+JsonParser *matrix_e2e_decrypt_room(PurpleConversation *conv,
+                                    struct _JsonObject *cevent)
 {
     JsonObject *cevent_content;
     const gchar *cevent_sender, *cevent_sender_key, *cevent_session_id;
@@ -1148,6 +1151,7 @@ void matrix_e2e_decrypt_room(PurpleConversation *conv,
     gchar *dupe_ciphertext = NULL;
     gchar *plaintext = NULL;
     size_t maxlen = 0;
+    JsonParser *plaintext_parser = NULL;
 
     cevent_sender = matrix_json_object_get_string_member(cevent, "sender");
     cevent_content = matrix_json_object_get_object_member(cevent, "content");
@@ -1165,7 +1169,7 @@ void matrix_e2e_decrypt_room(PurpleConversation *conv,
     if (!algorithm || strcmp(algorithm, "m.megolm.v1.aes-sha2")) {
         purple_debug_info("matrixprpl", "%s: Bad algorithm %s\n",
                                __func__, algorithm);
-        return;
+        goto out;
     }
 
     if (!cevent_sender || !cevent_content || !cevent_sender_key ||
@@ -1177,7 +1181,7 @@ void matrix_e2e_decrypt_room(PurpleConversation *conv,
                                __func__, cevent_sender, cevent_content,
                                cevent_sender_key, cevent_session_id,
                                cevent_device_id, cevent_ciphertext);
-        return;
+        goto out;
     }
 
     OlmInboundGroupSession *oigs = get_inbound_megolm_session(conv,
@@ -1191,7 +1195,7 @@ void matrix_e2e_decrypt_room(PurpleConversation *conv,
                           "%s: No Megolm session for %s/%s/%s/%s\n", __func__,
                           cevent_device_id, cevent_sender, cevent_sender_key,
                           cevent_session_id);
-        return;
+        goto out;
     }
     purple_debug_info("matrixprpl",
                       "%s: have Megolm session %p for %s/%s/%s/%s\n",
@@ -1232,12 +1236,22 @@ void matrix_e2e_decrypt_room(PurpleConversation *conv,
                 __func__, decrypt_len, maxlen);
         goto out;
     }
+    // TODO: Stash index somewhere - supposed to check it for validity
     plaintext[decrypt_len] = '\0';
     purple_debug_info("matrixprpl",
                       "%s: Decrypted megolm event as '%s' index=%zd\n",
                       __func__, plaintext, (size_t)index);
-    // TODO: Stash index somewhere - supposed to check it for validity
-    // TODO: JSON parse it and then send it back to matrix_room_handle_timeline_event
+
+    plaintext_parser = json_parser_new();
+    GError *err = NULL;
+    if (!json_parser_load_from_data(plaintext_parser,
+                                    plaintext, strlen(plaintext), &err)) {
+        purple_debug_info("matrixprpl",
+                          "%s: Failed to json parse decrypted plain text: %s\n",
+                          __func__, plaintext);
+        g_object_unref(plaintext_parser);
+        goto out;
+    }
 
 out:
     g_free(dupe_ciphertext);
@@ -1245,6 +1259,8 @@ out:
         clear_mem(plaintext, maxlen);
     }
     g_free(plaintext);
+
+    return plaintext_parser;
 }
 
 #else
@@ -1253,9 +1269,10 @@ void matrix_e2e_decrypt_d2d(PurpleConnection *pc, JsonObject *cevent)
 {
 }
 
-void matrix_e2e_decrypt_room(PurpleConversation *conv,
-                             struct _JsonObject *cevent)
+JsonParser *matrix_e2e_decrypt_room(PurpleConversation *conv,
+                                    struct _JsonObject *cevent)
 {
+    return NULL;
 }
 
 int matrix_e2e_get_device_keys(MatrixConnectionData *conn, const gchar *device_id)
diff --git a/matrix-e2e.h b/matrix-e2e.h
index 9483b4e..a3d953f 100644
--- a/matrix-e2e.h
+++ b/matrix-e2e.h
@@ -28,7 +28,7 @@ typedef struct _PurpleConversation PurpleConversation;
 int matrix_e2e_get_device_keys(MatrixConnectionData *conn, const gchar *device_id);
 void matrix_e2e_cleanup_connection(MatrixConnectionData *conn);
 void matrix_e2e_decrypt_d2d(struct _PurpleConnection *pc, struct _JsonObject *event);
-void matrix_e2e_decrypt_room(struct _PurpleConversation *conv, struct _JsonObject *event);
+JsonParser *matrix_e2e_decrypt_room(struct _PurpleConversation *conv, struct _JsonObject *event);
 void matrix_e2e_handle_sync_key_counts(struct _PurpleConnection *pc, struct _JsonObject *count_object, gboolean force_send);
 
 #endif
diff --git a/matrix-room.c b/matrix-room.c
index 6acaf0b..60ab229 100644
--- a/matrix-room.c
+++ b/matrix-room.c
@@ -932,6 +932,7 @@ void matrix_room_handle_timeline_event(PurpleConversation *conv,
     gchar *tmp_body = NULL;
     gchar *escaped_body = NULL;
     PurpleMessageFlags flags;
+    JsonParser *decrypted_parser = NULL;
 
     const gchar *sender_display_name;
     MatrixRoomMember *sender = NULL;
@@ -953,8 +954,27 @@ void matrix_room_handle_timeline_event(PurpleConversation *conv,
 
     if(!strcmp(event_type, "m.room.encrypted")) {
         purple_debug_info("matrixprpl", "Got an m.room.encrypted!\n");
-        matrix_e2e_decrypt_room(conv, json_event_obj);
-        return;
+        decrypted_parser = matrix_e2e_decrypt_room(conv, json_event_obj);
+        if (!decrypted_parser) {
+            purple_debug_warning("matrixprpl",
+                                 "Failed to decrypt m.room.encrypted");
+            return;
+        }
+        JsonNode *decrypted_node = json_parser_get_root(decrypted_parser);
+        JsonObject *decrypted_body;
+        decrypted_body = matrix_json_node_get_object(decrypted_node);
+        event_type = matrix_json_object_get_string_member(decrypted_body,
+                                                               "type");
+        json_content_obj = matrix_json_object_get_object_member(decrypted_body,
+                                                               "content");
+        // TODO: Check room_id matches
+        // TODO: Add some info about device trust etc
+        if (!event_type || !json_content_obj) {
+            purple_debug_warning("matrixprpl",
+                                 "Failed to find members of decrypted json");
+            g_object_unref(decrypted_parser);
+            return;
+        }
     }
 
     if(strcmp(event_type, "m.room.message") != 0) {
@@ -1023,6 +1043,9 @@ void matrix_room_handle_timeline_event(PurpleConversation *conv,
     serv_got_chat_in(conv->account->gc, g_str_hash(room_id),
             sender_display_name, flags, escaped_body, timestamp / 1000);
     g_free(escaped_body);
+    if (decrypted_parser) {
+        g_object_unref(decrypted_parser);
+    }
 }