add test

Author: devnexen

sapi/phpdbg/phpdbg_watch.c

@@ -316,7 +316,7 @@ void *phpdbg_watchpoint_userfaultfd_thread(void *phpdbg_globals) {
 
 	struct uffd_msg fault_msg = {0};
 	while (read(globals->watch_userfaultfd, &fault_msg, sizeof(fault_msg)) == sizeof(fault_msg)) {
-    	void *page = phpdbg_get_page_boundary((char *)(uintptr_t) fault_msg.arg.pagefault.address);
+		void *page = phpdbg_get_page_boundary((char *)(uintptr_t) fault_msg.arg.pagefault.address);
 		zend_hash_index_add_empty_element(globals->watchlist_mem, (zend_ulong) page);
 		struct uffdio_writeprotect unprotect = {
 			.mode = 0,

sapi/phpdbg/tests/gh13681.phpt

@@ -0,0 +1,39 @@
+--TEST--
+phpdbg_watch null pointer access
+--CREDITS--
+Yuancheng Jiang
+--SKIPIF--
+<?php
+if (getenv('SKIP_ASAN')) {
+    die("skip intentionally causes segfaults");
+}
+?>
+--FILE--
+<?php
+echo "*** Testing array_multisort() : Testing with anonymous arguments ***\n";
+var_dump(array_multisort(array(1,3,2,4)));
+$xconnect=$GLOBALS[array_rand($GLOBALS)];
+echo "Done\n";
+$a = [];
+$a[0] = 1;
+$a[0] = 2;
+$a = [0 => 3, 1 => 4];
+?>
+--PHPDBG--
+b 6
+r
+w a $a
+c
+q
+--EXPECTF--
+[Successful compilation of %s]
+prompt> [Breakpoint #0 added at %s:%d]
+prompt> *** Testing array_multisort() : Testing with anonymous arguments ***
+bool(true)
+Done
+[Breakpoint #0 at %s:%d, hits: 1]
+>00006: $a = [];
+ 00007: $a[0] = 1;
+ 00008: $a[0] = 2;
+prompt> prompt> [Script ended normally]
+prompt>