in_winevtlog: Plug memory errors on exceptions

Signed-off-by: Hiroshi Hatake <hiroshi@chronosphere.io>

Author: cosmo0920

plugins/in_winevtlog/pack.c

@@ -127,14 +127,23 @@ static int append_kv_line(flb_sds_t *text, const char *key,
     }
 
     *text = flb_sds_cat(*text, key, strlen(key));
+    if (*text == NULL) {
+        return -1;
+    }
+
     *text = flb_sds_cat(*text, "=", 1);
+    if (*text == NULL) {
+        return -1;
+    }
 
     if (val != NULL && val_len > 0) {
         *text = flb_sds_cat(*text, val, val_len);
+        if (*text == NULL) {
+            return -1;
+        }
     }
 
     *text = flb_sds_cat(*text, "\n", 1);
-
     if (*text == NULL) {
         return -1;
     }
@@ -1062,6 +1071,10 @@ void winevtlog_pack_text_event(PEVT_VARIANT system, WCHAR *message,
         append_kv_line(&text, "Message", NULL, 0);
     }
 
+    if (text == NULL) {
+        return;
+    }
+
     out_len = flb_sds_len(text);
     if (out_len > 0 && text[out_len - 1] == '\n') {
         out_len -= 1;
@@ -1072,9 +1085,11 @@ void winevtlog_pack_text_event(PEVT_VARIANT system, WCHAR *message,
         ret = flb_log_event_encoder_set_current_timestamp(ctx->log_encoder);
     }
 
-    ret = flb_log_event_encoder_append_body_string(ctx->log_encoder,
-                                                   ctx->render_event_text_key,
-                                                   flb_sds_len(ctx->render_event_text_key));
+    if (ret == FLB_EVENT_ENCODER_SUCCESS) {
+        ret = flb_log_event_encoder_append_body_string(ctx->log_encoder,
+                                                       ctx->render_event_text_key,
+                                                       flb_sds_len(ctx->render_event_text_key));
+    }
 
     if (ret == FLB_EVENT_ENCODER_SUCCESS) {
         ret = flb_log_event_encoder_append_body_string(ctx->log_encoder, text, out_len);

plugins/in_winevtlog/winevtlog.c

@@ -920,14 +920,16 @@ int winevtlog_read(struct winevtlog_channel *ch, struct winevtlog_config *ctx,
                     read_size += (system_size + message_size + string_inserts_size);
                     winevtlog_pack_xml_event(system_xml, message, string_inserts,
                                              count_inserts, ch, ctx);
+                }
 
-                    flb_free(string_inserts);
-                    flb_free(system_xml);
-                    if (message)
-                        flb_free(message);
+                flb_free(string_inserts);
+                flb_free(system_xml);
+                if (message) {
+                    flb_free(message);
                 }
             }
             else if (ctx->render_event_as_text) {
+                rendered_system = NULL;
                 render_system_event(ch->events[i], &rendered_system, &system_size);
                 message = get_description(ch->events[i], LANG_NEUTRAL, &message_size, ch->remote);
                 get_string_inserts(ch->events[i], &string_inserts, &count_inserts, &string_inserts_size);
@@ -937,11 +939,12 @@ int winevtlog_read(struct winevtlog_channel *ch, struct winevtlog_config *ctx,
                     winevtlog_pack_text_event(rendered_system, message, string_inserts,
                                               count_inserts, ch, ctx);
 
-                    flb_free(string_inserts);
-                    flb_free(rendered_system);
-                    if (message) {
-                        flb_free(message);
-                    }
+                }
+
+                flb_free(string_inserts);
+                flb_free(rendered_system);
+                if (message) {
+                    flb_free(message);
                 }
             }
             else {
@@ -953,11 +956,12 @@ int winevtlog_read(struct winevtlog_channel *ch, struct winevtlog_config *ctx,
                     read_size += (system_size + message_size + string_inserts_size);
                     winevtlog_pack_event(rendered_system, message, string_inserts,
                                          count_inserts, ch, ctx);
+                }
 
-                    flb_free(string_inserts);
-                    flb_free(rendered_system);
-                    if (message)
-                        flb_free(message);
+                flb_free(string_inserts);
+                flb_free(rendered_system);
+                if (message) {
+                    flb_free(message);
                 }
             }
         }