From 57295ef0e85640adcc3b85f08b12f09d54aad2d2 Mon Sep 17 00:00:00 2001
From: Tomi Salminen <tsalminen@forcepoint.com>
Date: Tue, 16 Apr 2019 13:55:39 +0300
Subject: [PATCH] Crash on SIGHUP when config file removed.

Reading config zeroed the returnable configuration only when the
config file was opened successfully. If not, the previously read
in configuration was returned, which was already freed.

Moved configuration zeroing to start of readin_config and added
unit test to test zero return.
---
 gram.y      |  2 +-
 test/util.c | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/gram.y b/gram.y
index 20af2f3..4115390 100644
--- a/gram.y
+++ b/gram.y
@@ -947,10 +947,10 @@ static void cleanup(void)
 
 struct Interface * readin_config(char const *path)
 {
+	IfaceList = 0;
 	FILE * in = fopen(path, "r");
 	if (in) {
 		filename = path;
-		IfaceList = 0;
 		num_lines = 1;
 		iface = 0;
 
diff --git a/test/util.c b/test/util.c
index b74b301..7124475 100644
--- a/test/util.c
+++ b/test/util.c
@@ -259,6 +259,20 @@ START_TEST(test_rand_between)
 }
 END_TEST
 
+START_TEST(test_cfg_removal_with_sighup)
+{
+  struct Interface *tmpIface = NULL;
+
+  tmpIface = readin_config("test/test1.conf");
+  ck_assert(tmpIface);
+
+  free_ifaces(tmpIface);
+
+  tmpIface = readin_config("test/file_that_should_not_exists.conf");
+  ck_assert(!tmpIface);
+}
+END_TEST
+
 Suite *util_suite(void)
 {
 	TCase *tc_safe_buffer = tcase_create("safe_buffer");
@@ -288,6 +302,7 @@ Suite *util_suite(void)
 
 	TCase *tc_misc = tcase_create("misc");
 	tcase_add_test(tc_misc, test_rand_between);
+	tcase_add_test(tc_misc, test_cfg_removal_with_sighup);
 
 	Suite *s = suite_create("util");
 	suite_add_tcase(s, tc_safe_buffer);