diff --git a/lib/roken/roken_gethostby.c b/lib/roken/roken_gethostby.c
index c99596c53..1d6c8ffe8 100644
--- a/lib/roken/roken_gethostby.c
+++ b/lib/roken/roken_gethostby.c
@@ -66,11 +66,13 @@ setup_int(const char *proxy_host, short proxy_port,
     memset(&dns_addr, 0, sizeof(dns_addr));
     if(dns_req)
 	free(dns_req);
+    dns_req = NULL;
     if(proxy_host) {
 	if(make_address(proxy_host, &dns_addr.sin_addr) != 0)
 	    return -1;
 	dns_addr.sin_port = htons(proxy_port);
-	asprintf(&dns_req, "http://%s:%d%s", dns_host, dns_port, dns_path);
+	if (asprintf(&dns_req, "http://%s:%d%s", dns_host, dns_port, dns_path) < 0)
+	    return -1;
     } else {
 	if(make_address(dns_host, &dns_addr.sin_addr) != 0)
 	    return -1;
@@ -135,7 +137,7 @@ roken_gethostby(const char *hostname)
 {
     int s;
     struct sockaddr_in addr;
-    char *request;
+    char *request = NULL;
     char buf[1024];
     int offset = 0;
     int n;
@@ -144,7 +146,8 @@ roken_gethostby(const char *hostname)
     if(dns_addr.sin_family == 0)
 	return NULL; /* no configured host */
     addr = dns_addr;
-    asprintf(&request, "GET %s?%s HTTP/1.0\r\n\r\n", dns_req, hostname);
+    if (asprintf(&request, "GET %s?%s HTTP/1.0\r\n\r\n", dns_req, hostname) < 0)
+	return NULL;
     if(request == NULL)
 	return NULL;
     s  = socket(AF_INET, SOCK_STREAM, 0);
diff --git a/lib/roken/setenv.c b/lib/roken/setenv.c
index 403db67cf..b4dbefef2 100644
--- a/lib/roken/setenv.c
+++ b/lib/roken/setenv.c
@@ -48,13 +48,12 @@ ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
 setenv(const char *var, const char *val, int rewrite)
 {
 #ifndef _WIN32
-    char *t;
+    char *t = NULL;
 
     if (!rewrite && getenv(var) != 0)
 	return 0;
 
-    asprintf (&t, "%s=%s", var, val);
-    if (t == NULL)
+    if (asprintf (&t, "%s=%s", var, val) < 0 || t == NULL)
 	return -1;
 
     if (putenv(t) == 0)
diff --git a/lib/roken/vsyslog.c b/lib/roken/vsyslog.c
index 91541fb73..aea7086d7 100644
--- a/lib/roken/vsyslog.c
+++ b/lib/roken/vsyslog.c
@@ -64,6 +64,7 @@ vsyslog(int pri, const char *fmt, va_list ap)
     char *fmt2;
     const char *p;
     char *p2;
+    int ret;
     int saved_errno = errno;
     int fmt_len  = strlen (fmt);
     int fmt2_len = fmt_len;
@@ -100,9 +101,9 @@ vsyslog(int pri, const char *fmt, va_list ap)
     }
     *p2 = '\0';
 
-    vasprintf (&buf, fmt2, ap);
+    ret = vasprintf (&buf, fmt2, ap);
     free (fmt2);
-    if (buf == NULL) {
+    if (ret < 0 || buf == NULL) {
 	simple_vsyslog (pri, fmt, ap);
 	return;
     }
diff --git a/lib/roken/write_pid.c b/lib/roken/write_pid.c
index 2a6ada586..505936984 100644
--- a/lib/roken/write_pid.c
+++ b/lib/roken/write_pid.c
@@ -38,11 +38,10 @@
 ROKEN_LIB_FUNCTION char * ROKEN_LIB_CALL
 pid_file_write (const char *progname)
 {
+    char *ret = NULL;
     FILE *fp;
-    char *ret;
 
-    asprintf (&ret, "%s%s.pid", _PATH_VARRUN, progname);
-    if (ret == NULL)
+    if (asprintf (&ret, "%s%s.pid", _PATH_VARRUN, progname) < 0 || ret == NULL)
 	return NULL;
     fp = fopen (ret, "w");
     if (fp == NULL) {