From be9855bca326901f7c7fc62dac0118534a0fe135 Mon Sep 17 00:00:00 2001
From: Nikos Mavrogiannopoulos <nmav@redhat.com>
Date: Tue, 20 May 2014 17:54:06 +0200
Subject: [PATCH] use safe_memset() instead of the plain memset() which can be
 optimized out.

---
 src/common.h | 15 +++++++++++++++
 src/main.c   |  4 ++--
 src/tlslib.c |  2 +-
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/common.h b/src/common.h
index a810cb98..0b2d5e9c 100644
--- a/src/common.h
+++ b/src/common.h
@@ -52,5 +52,20 @@ int recv_socket_msg(int fd, uint8_t cmd,
 
 const char* cmd_request_to_str(unsigned cmd);
 
+inline static
+void safe_memset(void *data, int c, size_t size)
+{
+	volatile unsigned volatile_zero = 0;
+	volatile char *vdata = (volatile char*)data;
+
+	/* This is based on a nice trick for safe memset,
+	 * sent by David Jacobson in the openssl-dev mailing list.
+	 */
+
+	do {
+		memset(data, c, size);
+	} while(vdata[volatile_zero] != c);
+}
+
 #endif
 
diff --git a/src/main.c b/src/main.c
index 433acdb2..447a310f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -566,7 +566,7 @@ void clear_lists(main_server_st *s)
 		if (ctmp->auth_ctx != NULL)
 			proc_auth_deinit(s, ctmp);
 		list_del(&ctmp->list);
-		memset(ctmp, 0, sizeof(*ctmp));
+		safe_memset(ctmp, 0, sizeof(*ctmp));
 		free(ctmp);
 		s->proc_list.total--;
 	}
@@ -584,7 +584,7 @@ void clear_lists(main_server_st *s)
 	tls_cache_deinit(s->tls_db);
 	ip_lease_deinit(&s->ip_leases);
 	ctl_handler_deinit(s);
-	memset(s->cookie_key, 0, sizeof(s->cookie_key));
+	safe_memset(s->cookie_key, 0, sizeof(s->cookie_key));
 }
 
 static void kill_children(main_server_st* s)
diff --git a/src/tlslib.c b/src/tlslib.c
index 21030f79..003cc643 100644
--- a/src/tlslib.c
+++ b/src/tlslib.c
@@ -203,7 +203,7 @@ struct htable_iter iter;
 	cache = htable_first(&db->ht, &iter);
 	while(cache != NULL) {
 		if (cache->session_data_size > 0) {
-	          	memset(cache->session_data, 0, cache->session_data_size);
+	          	safe_memset(cache->session_data, 0, cache->session_data_size);
 	          	cache->session_data_size = 0;
 	          	cache->session_id_size = 0;
 		}