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Created Sep 1, 2015

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commit e8429400d40e3c3aa4b22ba701991d698a2f3b2f
Author: Stanislav Malyshev <stas@php.net>
Date: Mon Aug 31 21:28:11 2015 -0700
Fix bug #70172 - Use After Free Vulnerability in unserialize()
diff --git a/ext/standard/tests/serialize/bug70172.phpt b/ext/standard/tests/serialize/bug70172.phpt
new file mode 100644
index 0000000..0e9d7ed
--- /dev/null
+++ b/ext/standard/tests/serialize/bug70172.phpt
@@ -0,0 +1,52 @@
+--TEST--
+Bug #70172 - Use After Free Vulnerability in unserialize()
+--FILE--
+<?php
+class obj implements Serializable {
+ var $data;
+ function serialize() {
+ return serialize($this->data);
+ }
+ function unserialize($data) {
+ $this->data = unserialize($data);
+ }
+}
+
+$fakezval = ptr2str(1122334455);
+$fakezval .= ptr2str(0);
+$fakezval .= "\x00\x00\x00\x00";
+$fakezval .= "\x01";
+$fakezval .= "\x00";
+$fakezval .= "\x00\x00";
+
+$inner = 'r:2;';
+$exploit = 'a:2:{i:0;i:1;i:1;C:3:"obj":'.strlen($inner).':{'.$inner.'}}';
+
+$data = unserialize($exploit);
+
+for ($i = 0; $i < 5; $i++) {
+ $v[$i] = $fakezval.$i;
+}
+
+var_dump($data);
+
+function ptr2str($ptr)
+{
+ $out = '';
+ for ($i = 0; $i < 8; $i++) {
+ $out .= chr($ptr & 0xff);
+ $ptr >>= 8;
+ }
+ return $out;
+}
+?>
+--EXPECTF--
+array(2) {
+ [0]=>
+ int(1)
+ [1]=>
+ object(obj)#%d (1) {
+ ["data"]=>
+ int(1)
+ }
+}
\ No newline at end of file
diff --git a/ext/standard/var.c b/ext/standard/var.c
index 7603ff2..33b976f 100644
--- a/ext/standard/var.c
+++ b/ext/standard/var.c
@@ -951,6 +951,8 @@ PHP_FUNCTION(unserialize)
int buf_len;
const unsigned char *p;
php_unserialize_data_t var_hash;
+ int oldlevel;
+ zval *old_rval = return_value;
if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &buf, &buf_len) == FAILURE) {
RETURN_FALSE;
@@ -970,6 +972,19 @@ PHP_FUNCTION(unserialize)
}
RETURN_FALSE;
}
+ if (return_value != old_rval) {
+ /*
+ * Terrible hack due to the fact that executor passes us zval *,
+ * but unserialize with r/R wants to replace it with another zval *
+ */
+ zval_dtor(old_rval);
+ *old_rval = *return_value;
+ zval_copy_ctor(old_rval);
+ var_push_dtor_no_addref(&var_hash, &return_value);
+ var_push_dtor_no_addref(&var_hash, &old_rval);
+ } else {
+ var_push_dtor(&var_hash, &return_value);
+ }
PHP_VAR_UNSERIALIZE_DESTROY(var_hash);
}
/* }}} */
diff --git a/ext/standard/var_unserializer.c b/ext/standard/var_unserializer.c
index ffaf680..5f2336e 100644
--- a/ext/standard/var_unserializer.c
+++ b/ext/standard/var_unserializer.c
@@ -1,4 +1,4 @@
-/* Generated by re2c 0.13.7.5 on Sun Aug 23 19:50:03 2015 */
+/* Generated by re2c 0.13.7.5 on Mon Aug 31 23:15:46 2015 */
#line 1 "ext/standard/var_unserializer.re"
/*
+----------------------------------------------------------------------+
@@ -69,7 +69,7 @@ PHPAPI void var_push_dtor(php_unserialize_data_t *var_hashx, zval **rval)
var_hash = (*var_hashx)->last_dtor;
#if VAR_ENTRIES_DBG
- fprintf(stderr, "var_push_dtor(%ld): %d\n", var_hash?var_hash->used_slots:-1L, Z_TYPE_PP(rval));
+ fprintf(stderr, "var_push_dtor(%p, %ld): %d\n", *rval, var_hash?var_hash->used_slots:-1L, Z_TYPE_PP(rval));
#endif
if (!var_hash || var_hash->used_slots == VAR_ENTRIES_MAX) {
@@ -100,7 +100,7 @@ PHPAPI void var_push_dtor_no_addref(php_unserialize_data_t *var_hashx, zval **rv
var_hash = (*var_hashx)->last_dtor;
#if VAR_ENTRIES_DBG
- fprintf(stderr, "var_push_dtor_no_addref(%ld): %d (%d)\n", var_hash?var_hash->used_slots:-1L, Z_TYPE_PP(rval), Z_REFCOUNT_PP(rval));
+ fprintf(stderr, "var_push_dtor_no_addref(%p, %ld): %d (%d)\n", *rval, var_hash?var_hash->used_slots:-1L, Z_TYPE_PP(rval), Z_REFCOUNT_PP(rval));
#endif
if (!var_hash || var_hash->used_slots == VAR_ENTRIES_MAX) {
@@ -179,6 +179,9 @@ PHPAPI void var_destroy(php_unserialize_data_t *var_hashx)
while (var_hash) {
for (i = 0; i < var_hash->used_slots; i++) {
+#if VAR_ENTRIES_DBG
+ fprintf(stderr, "var_destroy dtor(%p, %ld)\n", var_hash->data[i], Z_REFCOUNT_P(var_hash->data[i]));
+#endif
zval_ptr_dtor(&var_hash->data[i]);
}
next = var_hash->next;
@@ -239,7 +242,7 @@ static char *unserialize_str(const unsigned char **p, size_t *len, size_t maxlen
#define YYMARKER marker
-#line 247 "ext/standard/var_unserializer.re"
+#line 250 "ext/standard/var_unserializer.re"
@@ -484,7 +487,7 @@ PHPAPI int php_var_unserialize(UNSERIALIZE_PARAMETER)
-#line 488 "ext/standard/var_unserializer.c"
+#line 491 "ext/standard/var_unserializer.c"
{
YYCTYPE yych;
static const unsigned char yybm[] = {
@@ -544,9 +547,9 @@ yy2:
yych = *(YYMARKER = ++YYCURSOR);
if (yych == ':') goto yy95;
yy3:
-#line 839 "ext/standard/var_unserializer.re"
+#line 845 "ext/standard/var_unserializer.re"
{ return 0; }
-#line 550 "ext/standard/var_unserializer.c"
+#line 553 "ext/standard/var_unserializer.c"
yy4:
yych = *(YYMARKER = ++YYCURSOR);
if (yych == ':') goto yy89;
@@ -589,13 +592,13 @@ yy13:
goto yy3;
yy14:
++YYCURSOR;
-#line 833 "ext/standard/var_unserializer.re"
+#line 839 "ext/standard/var_unserializer.re"
{
/* this is the case where we have less data than planned */
php_error_docref(NULL TSRMLS_CC, E_NOTICE, "Unexpected end of serialized data");
return 0; /* not sure if it should be 0 or 1 here? */
}
-#line 599 "ext/standard/var_unserializer.c"
+#line 602 "ext/standard/var_unserializer.c"
yy16:
yych = *++YYCURSOR;
goto yy3;
@@ -626,7 +629,7 @@ yy20:
yych = *++YYCURSOR;
if (yych != '"') goto yy18;
++YYCURSOR;
-#line 687 "ext/standard/var_unserializer.re"
+#line 692 "ext/standard/var_unserializer.re"
{
size_t len, len2, len3, maxlen;
long elements;
@@ -642,6 +645,7 @@ yy20:
zval **args[1];
zval *arg_func_name;
+ if (!var_hash) return 0;
if (*start == 'C') {
custom_object = 1;
}
@@ -772,7 +776,7 @@ yy20:
return object_common2(UNSERIALIZE_PASSTHRU, elements);
}
-#line 776 "ext/standard/var_unserializer.c"
+#line 780 "ext/standard/var_unserializer.c"
yy25:
yych = *++YYCURSOR;
if (yych <= ',') {
@@ -797,15 +801,16 @@ yy27:
yych = *++YYCURSOR;
if (yych != '"') goto yy18;
++YYCURSOR;
-#line 679 "ext/standard/var_unserializer.re"
+#line 683 "ext/standard/var_unserializer.re"
{
+ if (!var_hash) return 0;
INIT_PZVAL(*rval);
return object_common2(UNSERIALIZE_PASSTHRU,
object_common1(UNSERIALIZE_PASSTHRU, ZEND_STANDARD_CLASS_DEF_PTR));
}
-#line 809 "ext/standard/var_unserializer.c"
+#line 814 "ext/standard/var_unserializer.c"
yy32:
yych = *++YYCURSOR;
if (yych == '+') goto yy33;
@@ -826,11 +831,12 @@ yy34:
yych = *++YYCURSOR;
if (yych != '{') goto yy18;
++YYCURSOR;
-#line 659 "ext/standard/var_unserializer.re"
+#line 662 "ext/standard/var_unserializer.re"
{
long elements = parse_iv(start + 2);
/* use iv() not uiv() in order to check data range */
*p = YYCURSOR;
+ if (!var_hash) return 0;
if (elements < 0) {
return 0;
@@ -846,7 +852,7 @@ yy34:
return finish_nested_data(UNSERIALIZE_PASSTHRU);
}
-#line 850 "ext/standard/var_unserializer.c"
+#line 856 "ext/standard/var_unserializer.c"
yy39:
yych = *++YYCURSOR;
if (yych == '+') goto yy40;
@@ -867,7 +873,7 @@ yy41:
yych = *++YYCURSOR;
if (yych != '"') goto yy18;
++YYCURSOR;
-#line 630 "ext/standard/var_unserializer.re"
+#line 633 "ext/standard/var_unserializer.re"
{
size_t len, maxlen;
char *str;
@@ -896,7 +902,7 @@ yy41:
ZVAL_STRINGL(*rval, str, len, 0);
return 1;
}
-#line 900 "ext/standard/var_unserializer.c"
+#line 906 "ext/standard/var_unserializer.c"
yy46:
yych = *++YYCURSOR;
if (yych == '+') goto yy47;
@@ -917,7 +923,7 @@ yy48:
yych = *++YYCURSOR;
if (yych != '"') goto yy18;
++YYCURSOR;
-#line 602 "ext/standard/var_unserializer.re"
+#line 605 "ext/standard/var_unserializer.re"
{
size_t len, maxlen;
char *str;
@@ -945,7 +951,7 @@ yy48:
ZVAL_STRINGL(*rval, str, len, 1);
return 1;
}
-#line 949 "ext/standard/var_unserializer.c"
+#line 955 "ext/standard/var_unserializer.c"
yy53:
yych = *++YYCURSOR;
if (yych <= '/') {
@@ -1033,7 +1039,7 @@ yy61:
}
yy63:
++YYCURSOR;
-#line 592 "ext/standard/var_unserializer.re"
+#line 595 "ext/standard/var_unserializer.re"
{
#if SIZEOF_LONG == 4
use_double:
@@ -1043,7 +1049,7 @@ use_double:
ZVAL_DOUBLE(*rval, zend_strtod((const char *)start + 2, NULL));
return 1;
}
-#line 1047 "ext/standard/var_unserializer.c"
+#line 1053 "ext/standard/var_unserializer.c"
yy65:
yych = *++YYCURSOR;
if (yych <= ',') {
@@ -1102,7 +1108,7 @@ yy73:
yych = *++YYCURSOR;
if (yych != ';') goto yy18;
++YYCURSOR;
-#line 577 "ext/standard/var_unserializer.re"
+#line 580 "ext/standard/var_unserializer.re"
{
*p = YYCURSOR;
INIT_PZVAL(*rval);
@@ -1117,7 +1123,7 @@ yy73:
return 1;
}
-#line 1121 "ext/standard/var_unserializer.c"
+#line 1127 "ext/standard/var_unserializer.c"
yy76:
yych = *++YYCURSOR;
if (yych == 'N') goto yy73;
@@ -1144,7 +1150,7 @@ yy79:
if (yych <= '9') goto yy79;
if (yych != ';') goto yy18;
++YYCURSOR;
-#line 550 "ext/standard/var_unserializer.re"
+#line 553 "ext/standard/var_unserializer.re"
{
#if SIZEOF_LONG == 4
int digits = YYCURSOR - start - 3;
@@ -1171,7 +1177,7 @@ yy79:
ZVAL_LONG(*rval, parse_iv(start + 2));
return 1;
}
-#line 1175 "ext/standard/var_unserializer.c"
+#line 1181 "ext/standard/var_unserializer.c"
yy83:
yych = *++YYCURSOR;
if (yych <= '/') goto yy18;
@@ -1179,24 +1185,24 @@ yy83:
yych = *++YYCURSOR;
if (yych != ';') goto yy18;
++YYCURSOR;
-#line 543 "ext/standard/var_unserializer.re"
+#line 546 "ext/standard/var_unserializer.re"
{
*p = YYCURSOR;
INIT_PZVAL(*rval);
ZVAL_BOOL(*rval, parse_iv(start + 2));
return 1;
}
-#line 1190 "ext/standard/var_unserializer.c"
+#line 1196 "ext/standard/var_unserializer.c"
yy87:
++YYCURSOR;
-#line 536 "ext/standard/var_unserializer.re"
+#line 539 "ext/standard/var_unserializer.re"
{
*p = YYCURSOR;
INIT_PZVAL(*rval);
ZVAL_NULL(*rval);
return 1;
}
-#line 1200 "ext/standard/var_unserializer.c"
+#line 1206 "ext/standard/var_unserializer.c"
yy89:
yych = *++YYCURSOR;
if (yych <= ',') {
@@ -1219,7 +1225,7 @@ yy91:
if (yych <= '9') goto yy91;
if (yych != ';') goto yy18;
++YYCURSOR;
-#line 513 "ext/standard/var_unserializer.re"
+#line 516 "ext/standard/var_unserializer.re"
{
long id;
@@ -1242,7 +1248,7 @@ yy91:
return 1;
}
-#line 1246 "ext/standard/var_unserializer.c"
+#line 1252 "ext/standard/var_unserializer.c"
yy95:
yych = *++YYCURSOR;
if (yych <= ',') {
@@ -1265,7 +1271,7 @@ yy97:
if (yych <= '9') goto yy97;
if (yych != ';') goto yy18;
++YYCURSOR;
-#line 492 "ext/standard/var_unserializer.re"
+#line 495 "ext/standard/var_unserializer.re"
{
long id;
@@ -1278,7 +1284,7 @@ yy97:
}
if (*rval != NULL) {
- zval_ptr_dtor(rval);
+ var_push_dtor_no_addref(var_hash, rval);
}
*rval = *rval_ref;
Z_ADDREF_PP(rval);
@@ -1286,9 +1292,9 @@ yy97:
return 1;
}
-#line 1290 "ext/standard/var_unserializer.c"
+#line 1296 "ext/standard/var_unserializer.c"
}
-#line 841 "ext/standard/var_unserializer.re"
+#line 847 "ext/standard/var_unserializer.re"
return 0;
diff --git a/ext/standard/var_unserializer.re b/ext/standard/var_unserializer.re
index f02602c..ed82152 100644
--- a/ext/standard/var_unserializer.re
+++ b/ext/standard/var_unserializer.re
@@ -67,7 +67,7 @@ PHPAPI void var_push_dtor(php_unserialize_data_t *var_hashx, zval **rval)
var_hash = (*var_hashx)->last_dtor;
#if VAR_ENTRIES_DBG
- fprintf(stderr, "var_push_dtor(%ld): %d\n", var_hash?var_hash->used_slots:-1L, Z_TYPE_PP(rval));
+ fprintf(stderr, "var_push_dtor(%p, %ld): %d\n", *rval, var_hash?var_hash->used_slots:-1L, Z_TYPE_PP(rval));
#endif
if (!var_hash || var_hash->used_slots == VAR_ENTRIES_MAX) {
@@ -98,7 +98,7 @@ PHPAPI void var_push_dtor_no_addref(php_unserialize_data_t *var_hashx, zval **rv
var_hash = (*var_hashx)->last_dtor;
#if VAR_ENTRIES_DBG
- fprintf(stderr, "var_push_dtor_no_addref(%ld): %d (%d)\n", var_hash?var_hash->used_slots:-1L, Z_TYPE_PP(rval), Z_REFCOUNT_PP(rval));
+ fprintf(stderr, "var_push_dtor_no_addref(%p, %ld): %d (%d)\n", *rval, var_hash?var_hash->used_slots:-1L, Z_TYPE_PP(rval), Z_REFCOUNT_PP(rval));
#endif
if (!var_hash || var_hash->used_slots == VAR_ENTRIES_MAX) {
@@ -177,6 +177,9 @@ PHPAPI void var_destroy(php_unserialize_data_t *var_hashx)
while (var_hash) {
for (i = 0; i < var_hash->used_slots; i++) {
+#if VAR_ENTRIES_DBG
+ fprintf(stderr, "var_destroy dtor(%p, %ld)\n", var_hash->data[i], Z_REFCOUNT_P(var_hash->data[i]));
+#endif
zval_ptr_dtor(&var_hash->data[i]);
}
next = var_hash->next;
@@ -501,7 +504,7 @@ PHPAPI int php_var_unserialize(UNSERIALIZE_PARAMETER)
}
if (*rval != NULL) {
- zval_ptr_dtor(rval);
+ var_push_dtor_no_addref(var_hash, rval);
}
*rval = *rval_ref;
Z_ADDREF_PP(rval);
@@ -660,6 +663,7 @@ use_double:
long elements = parse_iv(start + 2);
/* use iv() not uiv() in order to check data range */
*p = YYCURSOR;
+ if (!var_hash) return 0;
if (elements < 0) {
return 0;
@@ -677,6 +681,7 @@ use_double:
}
"o:" iv ":" ["] {
+ if (!var_hash) return 0;
INIT_PZVAL(*rval);
@@ -699,6 +704,7 @@ object ":" uiv ":" ["] {
zval **args[1];
zval *arg_func_name;
+ if (!var_hash) return 0;
if (*start == 'C') {
custom_object = 1;
}
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