Fix GH-14290: Member access within null pointer in extension spl

php_pcre_replace_impl() can fail and return NULL. We should take that
error condition into account. Because other failures return false, we
return false here as well.

At first, I also thought there was a potential memory leak in the error
check of replacement_str, but found that the error condition can never
trigger, so replace that with an assertion.

Closes GH-14292.

NEWS

@@ -2,6 +2,9 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? ????, PHP 8.2.21
 
+- SPL:
+  . Fixed bug GH-14290 (Member access within null pointer in extension spl).
+    (nielsdos)
 
 06 Jun 2024, PHP 8.2.20
 

ext/spl/spl_iterators.c

@@ -1904,12 +1904,17 @@ PHP_METHOD(RegexIterator, accept)
 			zval *replacement = zend_read_property(intern->std.ce, Z_OBJ_P(ZEND_THIS), "replacement", sizeof("replacement")-1, 1, &rv);
 			zend_string *replacement_str = zval_try_get_string(replacement);
 
-			if (UNEXPECTED(!replacement_str)) {
-				RETURN_THROWS();
-			}
+			/* Property type is ?string, so this should always succeed. */
+			ZEND_ASSERT(replacement_str != NULL);
 
 			result = php_pcre_replace_impl(intern->u.regex.pce, subject, ZSTR_VAL(subject), ZSTR_LEN(subject), replacement_str, -1, &count);
 
+			if (UNEXPECTED(!result)) {
+				zend_string_release(replacement_str);
+				zend_string_release_ex(subject, false);
+				RETURN_FALSE;
+			}
+
 			if (intern->u.regex.flags & REGIT_USE_KEY) {
 				zval_ptr_dtor(&intern->current.key);
 				ZVAL_STR(&intern->current.key, result);
@@ -1926,7 +1931,7 @@ PHP_METHOD(RegexIterator, accept)
 	if (intern->u.regex.flags & REGIT_INVERTED) {
 		RETVAL_BOOL(Z_TYPE_P(return_value) != IS_TRUE);
 	}
-	zend_string_release_ex(subject, 0);
+	zend_string_release_ex(subject, false);
 } /* }}} */
 
 /* {{{ Returns current regular expression */

ext/spl/tests/gh14290.phpt

@@ -0,0 +1,16 @@
+--TEST--
+GH-14290 (Member access within null pointer in extension spl)
+--INI--
+pcre.backtrack_limit=2
+pcre.jit=0
+--FILE--
+<?php
+$h = new ArrayIterator(['test' => 'test1']);
+$i = new RegexIterator($h, '/^test(.*)/', RegexIterator::REPLACE);
+foreach ($i as $name => $value) {
+    var_dump($name, $value);
+}
+echo "Done\n";
+?>
+--EXPECT--
+Done