don't allow newlines in LOG prefix (Phil Oester) (Closes: #312)
diff --git a/extensions/libipt_LOG.c b/extensions/libipt_LOG.c
index 74d6555..5e5d3fd 100644
--- a/extensions/libipt_LOG.c
+++ b/extensions/libipt_LOG.c
@@ -143,6 +143,10 @@
 				   "Maximum prefix length %u for --log-prefix",
 				   (unsigned int)sizeof(loginfo->prefix) - 1);
 
+		if (strlen(optarg) != strlen(strtok(optarg, "\n")))
+			exit_error(PARAMETER_PROBLEM,
+				   "Newlines not allowed in --log-prefix");
+
 		strcpy(loginfo->prefix, optarg);
 		*flags |= IPT_LOG_OPT_PREFIX;
 		break;