Fix #78210: Invalid pointer address

This is actually about three distinct issues:

* If an empty string is passed as $address to `stream_socket_sendto()`,
  the `sa` is not initialized, so we must not pass it as `addr` to
  `php_stream_xport_sendto()`.

* On POSIX, `recvfrom()` truncates messages which are too long to fit
  into the specified buffer (unless `MSG_PEEK` is given), discards the
  excessive bytes, and returns the buffer length.  On Windows, the same
  happens, but `recvfrom()` returns `SOCKET_ERROR` with the error code
  `WSAEMSGSIZE`.  We have to catch this for best POSIX compatibility.

* In `php_network_parse_network_address_with_port()`, we have to zero
  `in6` (not only its alias `sa`) to properly support IPv6.

Co-Authored-By: Nikita Popov <nikita.ppv@googlemail.com>

Author: cmb69

NEWS

@@ -4,6 +4,7 @@ PHP                                                                        NEWS
 
 - Core:
   . Fixed bug #79364 (When copy empty array, next key is unspecified). (cmb)
+  . Fixed bug #78210 (Invalid pointer address). (cmb, Nikita)
 
 - Spl:
   . Fixed bug #75673 (SplStack::unserialize() behavior). (cmb)

ext/standard/streamsfuncs.c

@@ -366,7 +366,7 @@ PHP_FUNCTION(stream_socket_sendto)
 		}
 	}
 
-	RETURN_LONG(php_stream_xport_sendto(stream, data, datalen, (int)flags, target_addr ? &sa : NULL, sl));
+	RETURN_LONG(php_stream_xport_sendto(stream, data, datalen, (int)flags, target_addr_len ? &sa : NULL, sl));
 }
 /* }}} */
 

main/network.c

@@ -512,9 +512,11 @@ PHPAPI int php_network_parse_network_address_with_port(const char *addr, zend_lo
 	zend_string *errstr = NULL;
 #if HAVE_IPV6
 	struct sockaddr_in6 *in6 = (struct sockaddr_in6*)sa;
-#endif
 
-	memset(sa, 0, sizeof(struct sockaddr));
+	memset(in6, 0, sizeof(struct sockaddr_in6));
+#else
+	memset(in4, 0, sizeof(struct sockaddr_in));
+#endif
 
 	if (*addr == '[') {
 		colon = memchr(addr + 1, ']', addrlen-1);

main/streams/xp_socket.c

@@ -272,6 +272,12 @@ static inline int sock_recvfrom(php_netstream_data_t *sock, char *buf, size_t bu
 		socklen_t sl = sizeof(sa);
 		ret = recvfrom(sock->socket, buf, XP_SOCK_BUF_SIZE(buflen), flags, (struct sockaddr*)&sa, &sl);
 		ret = (ret == SOCK_CONN_ERR) ? -1 : ret;
+#ifdef PHP_WIN32
+		/* POSIX discards excess bytes without signalling failure; emulate this on Windows */
+		if (ret == -1 && WSAGetLastError() == WSAEMSGSIZE) {
+			ret = buflen;
+		}
+#endif
 		if (sl) {
 			php_network_populate_name_from_sockaddr((struct sockaddr*)&sa, sl,
 					textaddr, addr, addrlen);