qxl abi: parse QXLMessage.

3 files changed, 41 insertions, 4 deletions

diff --git a/server/red_parse_qxl.c b/server/red_parse_qxl.c
index f7de6cf..6c8eb69 100644
--- a/server/red_parse_qxl.c
+++ b/server/red_parse_qxl.c
@@ -330,3 +330,25 @@ void red_put_update_cmd(RedUpdateCmd *red)
 {
     /* nothing yet */
 }
+
+void red_get_message(RedMemSlotInfo *slots, int group_id,
+                     RedMessage *red, SPICE_ADDRESS addr)
+{
+    QXLMessage *qxl;
+
+    /*
+     * security alert:
+     *   qxl->data[0] size isn't specified anywhere -> can't verify
+     *   luckily this is for debug logging only,
+     *   so we can just ignore it by default.
+     */
+    qxl = (QXLMessage *)get_virt(slots, addr, sizeof(*qxl), group_id);
+    red->release_info  = &qxl->release_info;
+    red->data          = qxl->data;
+}
+
+void red_put_message(RedMessage *red)
+{
+    /* nothing yet */
+}
+
diff --git a/server/red_parse_qxl.h b/server/red_parse_qxl.h
index bc2dd4e..b4baed8 100644
--- a/server/red_parse_qxl.h
+++ b/server/red_parse_qxl.h
@@ -60,6 +60,11 @@ typedef struct SPICE_ATTR_PACKED RedUpdateCmd {
     uint32_t surface_id;
 } RedUpdateCmd;
 
+typedef struct SPICE_ATTR_PACKED RedMessage {
+    QXLReleaseInfo *release_info;
+    uint8_t *data;
+} RedMessage;
+
 void red_get_drawable(RedMemSlotInfo *slots, int group_id,
                       RedDrawable *red, SPICE_ADDRESS addr);
 void red_get_compat_drawable(RedMemSlotInfo *slots, int group_id,
@@ -70,4 +75,8 @@ void red_get_update_cmd(RedMemSlotInfo *slots, int group_id,
                         RedUpdateCmd *red, SPICE_ADDRESS addr);
 void red_put_update_cmd(RedUpdateCmd *red);
 
+void red_get_message(RedMemSlotInfo *slots, int group_id,
+                     RedMessage *red, SPICE_ADDRESS addr);
+void red_put_message(RedMessage *red);
+
 #endif
diff --git a/server/red_worker.c b/server/red_worker.c
index b90c3f9..34f723f 100644
--- a/server/red_worker.c
+++ b/server/red_worker.c
@@ -5057,13 +5057,19 @@ static int red_process_commands(RedWorker *worker, uint32_t max_pipe_size)
             break;
         }
         case QXL_CMD_MESSAGE: {
+            RedMessage message;
             QXLReleaseInfoExt release_info_ext;
-            QXLMessage *message = (QXLMessage *)get_virt(&worker->mem_slots, ext_cmd.cmd.data,
-                                                         sizeof(QXLMessage), ext_cmd.group_id);
-            red_printf("MESSAGE: %s", message->data);
+
+            red_get_message(&worker->mem_slots, ext_cmd.group_id,
+                            &message, ext_cmd.cmd.data);
+#ifdef DEBUG
+            /* alert: accessing message.data is insecure */
+            red_printf("MESSAGE: %s", message.data);
+#endif
             release_info_ext.group_id = ext_cmd.group_id;
-            release_info_ext.info = &message->release_info;
+            release_info_ext.info = message.release_info;
             worker->qxl->st->qif->release_resource(worker->qxl, release_info_ext);
+            red_put_message(&message);
             break;
         }
         case QXL_CMD_SURFACE: {