[HQ-93] un-clobber stack data in sigar_gethostbyname

include/sigar_private.h

@@ -239,4 +239,23 @@ int sigar_get_iftype(const char *name, int *type, int *inst);
 #define SIGAR_NIC_ETHERNET "Ethernet"
 #define SIGAR_NIC_NETROM   "AMPR NET/ROM"
 
+#ifdef WIN32
+#else
+#include <netdb.h>
+#endif
+
+#define SIGAR_GETHOSTBYNAME_LEN 512
+#if defined(__hpux) || defined(_AIX)
+#define SIGAR_HAS_HOSTENT_DATA
+#endif
+
+typedef struct {
+    char buffer[SIGAR_GETHOSTBYNAME_LEN];
+    struct hostent hs;
+    int error;
+#ifdef SIGAR_HAS_HOSTENT_DATA
+    struct hostent_data hd;
+#endif
+} sigar_hostent_t;
+
 #endif

include/sigar_util.h

@@ -30,7 +30,8 @@
 
 char *sigar_uitoa(char *buf, unsigned int n, int *len);
 
-struct hostent *sigar_gethostbyname(const char *name);
+struct hostent *sigar_gethostbyname(const char *name,
+                                    sigar_hostent_t *data);
 
 SIGAR_INLINE char *sigar_skip_line(char *buffer, int buflen);
 

src/sigar.c

@@ -1547,34 +1547,26 @@ static int fqdn_ip_get(sigar_t *sigar, char *name)
     return SIGAR_OK;
 }
 
-#ifdef WIN32
+struct hostent *sigar_gethostbyname(const char *name,
-#else
+                                    sigar_hostent_t *data)
-#include <netdb.h>
-#endif
-
-#define GETHOSTBYNAME_LEN 512
-#if defined(__hpux) || defined(_AIX)
-#define HAS_HOSTENT_DATA
-#endif
-
-struct hostent *sigar_gethostbyname(const char *name)
 {
-    char buffer[GETHOSTBYNAME_LEN];
+    struct hostent *hp = NULL;
-    struct hostent hs, *hp;
-    int err;
-#if defined(HAS_HOSTENT_DATA)
-    struct hostent_data hd;
-#endif
  
 #if defined(__linux__)
-    gethostbyname_r(name, &hs, buffer, sizeof(buffer),
+    gethostbyname_r(name, &data->hs,
-                    &hp, &err);
+                    data->buffer, sizeof(data->buffer),
+                    &hp, &data->error);
 #elif defined(__sun)
-    hp = gethostbyname_r(name, &hs, buffer, sizeof(buffer),
+    hp = gethostbyname_r(name, &data->hs,
-                         &err);
+                         data->buffer, sizeof(data->buffer),
-#elif defined(HAS_HOSTENT_DATA)
+                         &data->error);
-    gethostbyname_r(name, &hs, &hd);
+#elif defined(SIGAR_HAS_HOSTENT_DATA)
-    hp = &hs;
+    if (gethostbyname_r(name, &data->hs, &data->hd) == 0) {
+        hp = &data->hs;
+    }
+    else {
+        data->error = h_errno;
+    }
 #else
     hp = gethostbyname(name);
 #endif
@@ -1593,6 +1585,7 @@ struct hostent *sigar_gethostbyname(const char *name)
 
 SIGAR_DECLARE(int) sigar_fqdn_get(sigar_t *sigar, char *name, int namelen)
 {
+    sigar_hostent_t data;
     struct hostent *p;
     char domain[SIGAR_FQDN_LEN + 1];
 #ifdef WIN32
@@ -1618,7 +1611,7 @@ SIGAR_DECLARE(int) sigar_fqdn_get(sigar_t *sigar, char *name, int namelen)
     }
 
     /* XXX use _r versions of these functions. */
-    if (!(p = sigar_gethostbyname(name))) {
+    if (!(p = sigar_gethostbyname(name, &data))) {
         if (SIGAR_LOG_IS_DEBUG(sigar)) {
             sigar_log_printf(sigar, SIGAR_LOG_DEBUG,
                              "[fqdn] gethostbyname(%s) failed: %s",

src/sigar_util.c

@@ -496,12 +496,13 @@ int sigar_cpu_mhz_from_model(char *model)
 static enum clnt_stat get_sockaddr(struct sockaddr_in *addr, char *host)
 {
     register struct hostent *hp;
+    sigar_hostent_t data;
 
     memset(addr, 0, sizeof(struct sockaddr_in));
     addr->sin_family = AF_INET;
 
     if ((addr->sin_addr.s_addr = inet_addr(host)) == -1) {
-        if (!(hp = sigar_gethostbyname(host))) {
+        if (!(hp = sigar_gethostbyname(host, &data))) {
             return RPC_UNKNOWNHOST;
         }
         memcpy(&addr->sin_addr, hp->h_addr, hp->h_length);