diff --git a/configure.ac b/configure.ac
index 2f4d8d8..bf34d6a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -25,6 +25,10 @@ if test x"$have_pamheader" != x"yes"; then
 	AC_MSG_ERROR(You are missing PAM headers)
 fi
 
+AC_CHECK_FUNC([memset_s], [
+   AC_DEFINE([HAVE_MEMSET_S], [1], [Define if has memset_s])
+])
+
 case "$host" in
 (*-*-linux*)
 	PAM_MODDIR="\$(slibdir)/security";
diff --git a/pam_shield.c b/pam_shield.c
index e594fc3..dbabab6 100644
--- a/pam_shield.c
+++ b/pam_shield.c
@@ -98,7 +98,7 @@ static _pam_shield_db_rec_t *new_db_record(int window_size) {
     logmsg(LOG_CRIT, "new_db_record(): out of memory allocating %d bytes", size);
     return NULL;
   }
-  memset(record, 0, size);
+  memset_s(record, size, 0, size);
   record->max_entries = window_size;
   return record;
 }
@@ -117,7 +117,7 @@ static struct addrinfo *get_addr_info(char *rhost) {
   struct addrinfo hints, *res;
   int err;
 
-  memset(&hints, 0, sizeof(struct addrinfo));
+  memset_s(&hints, sizeof(struct addrinfo), 0, sizeof(struct addrinfo));
   hints.ai_family = PF_UNSPEC;
   hints.ai_socktype = SOCK_STREAM;
 
diff --git a/pam_shield_lib.c b/pam_shield_lib.c
index cc44099..321aea9 100644
--- a/pam_shield_lib.c
+++ b/pam_shield_lib.c
@@ -69,7 +69,7 @@ ip_list *new_ip_list(void) {
   if ((ip = (ip_list *)malloc(sizeof(ip_list))) == NULL)
     return NULL;
 
-  memset(ip, 0, sizeof(ip_list));
+  memset_s(ip, sizeof(ip_list), 0, sizeof(ip_list));
   return ip;
 }
 
@@ -171,7 +171,7 @@ name_list *new_name_list(char *name) {
   if ((n = (name_list *)malloc(sizeof(name_list) + strlen(name))) == NULL)
     return NULL;
 
-  memset(n, 0, sizeof(name_list));
+  memset_s(n, sizeof(name_list), 0, sizeof(name_list));
   snprintf(n->name, sizeof(n->name), "%s", name);
   return n;
 }
@@ -347,7 +347,7 @@ void ip_bitmask(int bits, unsigned char *mask, int size) {
   if (mask == NULL)
     return;
 
-  memset(mask, 0, size);
+  memset_s(mask, size, 0, size);
 
   if (bits < 0)
     bits = 0;
@@ -397,7 +397,7 @@ int allow_ip(char *ipnum, int line_no) {
   /* try network address as IPv4 */
   if (inet_pton(AF_INET, ipnum, &ip->ip.in) > 0) {
     if (netmask == NULL) { /* no netmask given, treat as host */
-      memset(&ip->mask.in.s_addr, 0xff, sizeof(ip->mask.in.s_addr));
+      memset_s(&ip->mask.in.s_addr, sizeof(ip->mask.in.s_addr), 0xff, sizeof(ip->mask.in.s_addr));
       add_ip_list(&allow_ipv4_list, ip);
       return 0;
     }
@@ -426,7 +426,7 @@ int allow_ip(char *ipnum, int line_no) {
   /* try network address as IPv6 */
   if (inet_pton(AF_INET6, ipnum, &ip->ip.in6) > 0) {
     if (netmask == NULL) { /* no netmask given, treat as host */
-      memset(ip->mask.in6.s6_addr, 0xff, sizeof(ip->mask.in6.s6_addr));
+      memset_s(ip->mask.in6.s6_addr, sizeof(ip->mask.in6.s6_addr), 0xff, sizeof(ip->mask.in6.s6_addr));
       add_ip_list(&allow_ipv6_list, ip);
       return 0;
     }
@@ -758,4 +758,18 @@ void fatal_func(const char *str) {
     logmsg(LOG_ERR, "failed to create new gdbm file '%s' : %s", dbfile, gdbm_strerror(gdbm_errno));
 }
 
+#ifndef HAVE_MEMSET_S
+void memset_s(void *dest, size_t destsz, int c, size_t count) {
+  if (count > destsz) {
+    fprintf(stderr, "Error: count exceeds destsz\n");
+    exit(EXIT_FAILURE);
+  }
+
+  unsigned char *p = (unsigned char *)dest;
+  while (count--) {
+    *p++ = (unsigned char)c;
+  }
+}
+#endif
+
 #pragma GCC visibility pop
diff --git a/pam_shield_lib.h b/pam_shield_lib.h
index 3698ec8..576403b 100644
--- a/pam_shield_lib.h
+++ b/pam_shield_lib.h
@@ -165,4 +165,8 @@ int expire_record(_pam_shield_db_rec_t *record);
 /* gdbm has encountered a fatal error */
 void fatal_func(const char *str);
 
+#ifndef HAVE_MEMSET_S
+void memset_s(void *dest, size_t destsz, int c, size_t count);
+#endif
+
 #pragma GCC visibility pop