Merge remote-tracking branch 'security/bug76248' into PHP-5.6

* security/bug76248:
  Fix bug #76248 - Malicious LDAP-Server Response causes Crash

Author: smalyshev

ext/ldap/ldap.c

@@ -1103,7 +1103,11 @@ PHP_FUNCTION(ldap_get_entries)
 
 		add_assoc_long(tmp1, "count", num_attrib);
 		dn = ldap_get_dn(ldap, ldap_result_entry);
-		add_assoc_string(tmp1, "dn", dn, 1);
+		if (dn) {
+			add_assoc_string(tmp1, "dn", dn, 1);
+		} else {
+			add_assoc_null(tmp1, "dn");
+		}
 #if (LDAP_API_VERSION > 2000) || HAVE_NSLDAP || HAVE_ORALDAP || WINDOWS
 		ldap_memfree(dn);
 #else

ext/ldap/tests/bug76248.phpt

@@ -0,0 +1,40 @@
+--TEST--
+Bug #76248 (Malicious LDAP-Server Response causes Crash)
+--SKIPIF--
+<?php
+require_once('skipif.inc');
+if (!function_exists('pcntl_fork')) die('skip fork not available');
+?>
+--FILE--
+<?php
+$pid = pcntl_fork();
+const PORT = 12345;
+if ($pid == 0) {
+	// child
+    $server = stream_socket_server("tcp://127.0.0.1:12345");
+	$socket = stream_socket_accept($server, 3);
+	fwrite($socket, base64_decode("MAwCAQFhBwoBAAQABAAweQIBAmR0BJljbj1yb290LGRjPWV4YW1wbGUsZGM9Y29tMFcwIwQLb2JqZWN0Q2xhc3MxFAQSb3JnYW5pemF0aW9uYWxSb2xlMAwEAmNuMQYEBHJvb3QwIgQLZGVzY3JpcHRpb24xEwQRRGlyZWN0b3J5IE1hbmFnZXIwDAIBAmUHCgEABAAEADB5AgEDZHQEmWNuPXJvb3QsZGM9ZXhhbXBsZSxkYz1jb20wVzAjBAtvYmplY3RDbGFzczEUBBJvcmdhbml6YXRpb25hbFJvbGUwDAQCY24xBgQEcm9vdDAiBAtkZXNjcmlwdGlvbjETBBFEaXJlY3RvcnkgTWFuYWdlcjAMAgEDZQcKAQAEAAQA"));
+	fflush($socket);	
+} else {
+	// parent
+	$ds = ldap_connect("127.0.0.1", PORT);
+	ldap_set_option($ds, LDAP_OPT_PROTOCOL_VERSION, 3);
+	$b = ldap_bind($ds, "cn=root,dc=example,dc=com", "secret");
+
+	$s = ldap_search($ds, "dc=example,dc=com", "(cn=root)"); 
+	$tt = ldap_get_entries($ds, $s);
+	var_dump($tt);
+}
+?>
+--EXPECT--
+array(2) {
+  ["count"]=>
+  int(1)
+  [0]=>
+  array(2) {
+    ["count"]=>
+    int(0)
+    ["dn"]=>
+    NULL
+  }
+}