ext/standard: Fix ip2long in AIX to treat IPs with leading zeros as invalid like LINUX

close GH-21296

Author: reshmavk

NEWS

@@ -21,6 +21,7 @@ PHP                                                                        NEWS
 - Standard:
   . Fixed bug GH-21689 (version_compare() incorrectly handles versions ending
     with a dot). (timwolla)
+  . Fixed ip2long() leading zeros handling inconsistency on AIX. (ayappanec)
 
 07 May 2026, PHP 8.4.21
 

ext/standard/basic_functions.c

@@ -598,6 +598,20 @@ PHP_FUNCTION(ip2long)
 	if (addr_len == 0 || inet_pton(AF_INET, addr, &ip) != 1) {
 		RETURN_FALSE;
 	}
+#ifdef _AIX
+	/*
+	AIX accepts IP strings with extraneous 0 (192.168.042.42 will be treated as
+	192.168.42.42), while Linux doesn't.
+	For consistency, we convert back the IP to a string and check if it is equal to
+	the original string. If not, the IP should be considered invalid.
+	*/
+	char str[INET_ADDRSTRLEN];
+	const char* result = inet_ntop(AF_INET, &ip, str, sizeof(str));
+	ZEND_ASSERT(result != NULL);
+	if (strcmp(addr, result) != 0) {
+		RETURN_FALSE;
+	}
+#endif
 	RETURN_LONG(ntohl(ip.s_addr));
 }
 /* }}} */