Fix GH-18480: array_splice overflow on array length with offset.

close GH-18483

Author: devnexen

NEWS

@@ -2,6 +2,10 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? ????, PHP 8.3.22
 
+- Core:
+  . Fixed GH-18480 (array_splice with large values for offset/length arguments).
+    (nielsdos/David Carlier)
+
 - Curl:
   . Fixed GH-18460 (curl_easy_setopt with CURLOPT_USERPWD/CURLOPT_USERNAME/
     CURLOPT_PASSWORD set the Authorization header when set to NULL).

ext/standard/array.c

@@ -3252,17 +3252,17 @@ static void php_splice(HashTable *in_hash, zend_long offset, zend_long length, H
 
 		/* If hash for removed entries exists, go until offset+length and copy the entries to it */
 		if (removed != NULL) {
-			for ( ; pos < offset + length && idx < in_hash->nNumUsed; idx++, entry++) {
+			for ( ; pos - offset < length && idx < in_hash->nNumUsed; idx++, entry++) {
 				if (Z_TYPE_P(entry) == IS_UNDEF) continue;
 				pos++;
 				Z_TRY_ADDREF_P(entry);
 				zend_hash_next_index_insert_new(removed, entry);
 				zend_hash_packed_del_val(in_hash, entry);
 			}
 		} else { /* otherwise just skip those entries */
-			int pos2 = pos;
+			zend_long pos2 = pos;
 
-			for ( ; pos2 < offset + length && idx < in_hash->nNumUsed; idx++, entry++) {
+			for ( ; pos2 - offset < length && idx < in_hash->nNumUsed; idx++, entry++) {
 				if (Z_TYPE_P(entry) == IS_UNDEF) continue;
 				pos2++;
 				zend_hash_packed_del_val(in_hash, entry);
@@ -3317,7 +3317,7 @@ static void php_splice(HashTable *in_hash, zend_long offset, zend_long length, H
 
 		/* If hash for removed entries exists, go until offset+length and copy the entries to it */
 		if (removed != NULL) {
-			for ( ; pos < offset + length && idx < in_hash->nNumUsed; idx++, p++) {
+			for ( ; pos - offset < length && idx < in_hash->nNumUsed; idx++, p++) {
 				if (Z_TYPE(p->val) == IS_UNDEF) continue;
 				pos++;
 				entry = &p->val;
@@ -3330,9 +3330,9 @@ static void php_splice(HashTable *in_hash, zend_long offset, zend_long length, H
 				zend_hash_del_bucket(in_hash, p);
 			}
 		} else { /* otherwise just skip those entries */
-			int pos2 = pos;
+			zend_long pos2 = pos;
 
-			for ( ; pos2 < offset + length && idx < in_hash->nNumUsed; idx++, p++) {
+			for ( ; pos2 - offset < length && idx < in_hash->nNumUsed; idx++, p++) {
 				if (Z_TYPE(p->val) == IS_UNDEF) continue;
 				pos2++;
 				zend_hash_del_bucket(in_hash, p);

ext/standard/tests/array/gh18480.phpt

@@ -0,0 +1,40 @@
+--TEST--
+GH-18480 (array_splice overflow with large offset / length values)
+--FILE--
+<?php
+
+foreach ([PHP_INT_MIN, PHP_INT_MAX] as $length) {
+	$a = [PHP_INT_MAX];
+	$offset = PHP_INT_MAX;
+	var_dump(array_splice($a,$offset, $length));
+	$a = [PHP_INT_MAX];
+	$offset = PHP_INT_MIN;
+	var_dump(array_splice($a,$offset, $length));
+	$a = ["a" => PHP_INT_MAX];
+	$offset = PHP_INT_MAX;
+	var_dump(array_splice($a,$offset, $length));
+	$a = ["a" => PHP_INT_MAX];
+	$offset = PHP_INT_MIN;
+	var_dump(array_splice($a,$offset, $length));
+}
+--EXPECTF--
+array(0) {
+}
+array(0) {
+}
+array(0) {
+}
+array(0) {
+}
+array(0) {
+}
+array(1) {
+  [0]=>
+  int(%d)
+}
+array(0) {
+}
+array(1) {
+  ["a"]=>
+  int(%d)
+}