From 3798eb6fd5dddb211b01d41495072fd9858d4e32 Mon Sep 17 00:00:00 2001
From: Stanislav Malyshev <stas@php.net>
Date: Tue, 12 Jul 2016 23:27:45 -0700
Subject: [PATCH] Fix bug #72562 - destroy var_hash properly
---
ext/session/session.c | 3 ++-
ext/session/tests/bug72562.phpt | 44 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 46 insertions(+), 1 deletion(-)
create mode 100644 ext/session/tests/bug72562.phpt
diff --git a/ext/session/session.c b/ext/session/session.c
index f5439ea..cb6cc01 100644
--- a/ext/session/session.c
+++ b/ext/session/session.c
@@ -837,6 +837,7 @@ PS_SERIALIZER_DECODE_FUNC(php_binary) /* {{{ */
namelen = ((unsigned char)(*p)) & (~PS_BIN_UNDEF);
if (namelen < 0 || namelen > PS_BIN_MAX || (p + namelen) >= endptr) {
+ PHP_VAR_UNSERIALIZE_DESTROY(var_hash);
return FAILURE;
}
diff --git a/ext/session/tests/bug72562.phpt b/ext/session/tests/bug72562.phpt
new file mode 100644
index 0000000..d85e48b
--- /dev/null
+++ b/ext/session/tests/bug72562.phpt
@@ -0,0 +1,44 @@
+--TEST--
+Bug #72562: Use After Free in unserialize() with Unexpected Session Deserialization
+--SKIPIF--
+<?php include('skipif.inc'); ?>
+--FILE--
+<?php
+
+ini_set('session.serialize_handler', 'php_binary');
+session_start();
+$sess = "\x1xi:1;\x2y";
+session_decode($sess);
+$uns_1 = '{';
+$out_1[] = unserialize($uns_1);
+unset($out_1);
+$fakezval = ptr2str(1122334455);
+$fakezval .= ptr2str(0);
+$fakezval .= "\x00\x00\x00\x00";
+$fakezval .= "\x01";
+$fakezval .= "\x00";
+$fakezval .= "\x00\x00";
+for ($i = 0; $i < 5; $i++) {
+ $v[$i] = $fakezval.$i;
+}
+$uns_2 = 'R:2;';
+$out_2 = unserialize($uns_2);
+var_dump($out_2);
+
+function ptr2str($ptr)
+{
+ $out = '';
+ for ($i = 0; $i < 8; $i++) {
+ $out .= chr($ptr & 0xff);
+ $ptr >>= 8;
+ }
+ return $out;
+}
+?>
+--EXPECTF--
+Warning: session_decode(): Failed to decode session object. Session has been destroyed in %s/bug72562.php on line %d
+
+Notice: unserialize(): Error at offset 0 of 1 bytes in %s/bug72562.php on line %d
+
+Notice: unserialize(): Error at offset 4 of 4 bytes in %s/bug72562.php on line %d
+bool(false)