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Bug #72848 integer overflow in quoted_printable_encode caused heap corruption
Submitted: 2016-08-16 07:38 UTC Modified: 2017-02-13 01:45 UTC
From: minhrau dot vc dot 365 at gmail dot com Assigned: stas
Status: Closed Package: *General Issues
PHP Version: 5.6.24 OS: ALL
Private report: No CVE-ID:
 [2016-08-16 07:38 UTC] minhrau dot vc dot 365 at gmail dot com
Description:
------------
An integer overflow in function php_quot_print_encode, will lead to heap corruption. Please check the detail of this vuln in comment below:

PHPAPI unsigned char *php_quot_print_encode(const unsigned char *str, size_t length, size_t *ret_length) /* {{{ */
{
	unsigned long lp = 0;
	unsigned char c, *ret, *d;
	char *hex = "0123456789ABCDEF";

	ret = safe_emalloc(3, length + (((3 * length)/(PHP_QPRINT_MAXL-9)) + 1), 1); // the size of safe_emalloc is larger than INT_MAX
	d = ret;

	while (length--) { 

Test script:
---------------
<?php

ini_set('memory_limit', -1);


$str = str_repeat('รด', 0xffffffff/4);

var_dump(strlen($str));


$str1 = quoted_printable_encode($str);
unset($str);
var_dump(strlen($str1));
chunk_split($str1, 11, $str1);
?>


Expected result:
----------------
No Crash

Actual result:
--------------
Starting program: /home/minhrau/PHP-5.6.24/sapi/cli/php testquoted_printable_encode_negative.php
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/libthread_db.so.1".
int(2147483646)
int(-1879048199)

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff1d92f78 in __memcpy_avx_unaligned () from /usr/lib/libc.so.6
(gdb) bt
#0  0x00007ffff1d92f78 in __memcpy_avx_unaligned () from /usr/lib/libc.so.6
#1  0x00000000006b053f in zif_chunk_split (ht=<optimized out>, return_value=0x7ffff7fa2fc8, return_value_ptr=<optimized out>, this_ptr=<optimized out>, return_value_used=<optimized out>) at /home/minhrau/PHP-5.6.24/ext/standard/string.c:2221
#2  0x00000000007f908d in zend_do_fcall_common_helper_SPEC (execute_data=<optimized out>) at /home/minhrau/PHP-5.6.24/Zend/zend_vm_execute.h:558
#3  0x0000000000783b4e in execute_ex (execute_data=0x7ffff7f6f248) at /home/minhrau/PHP-5.6.24/Zend/zend_vm_execute.h:363
#4  0x000000000074ed41 in zend_execute_scripts (type=type@entry=8, retval=retval@entry=0x0, file_count=file_count@entry=3) at /home/minhrau/PHP-5.6.24/Zend/zend.c:1341
#5  0x00000000006ed0d0 in php_execute_script (primary_file=primary_file@entry=0x7fffffffd0d0) at /home/minhrau/PHP-5.6.24/main/main.c:2613
#6  0x00000000007faa97 in do_cli (argc=2, argv=0xf8c960) at /home/minhrau/PHP-5.6.24/sapi/cli/php_cli.c:994
#7  0x00000000004361e4 in main (argc=2, argv=0xf8c960) at /home/minhrau/PHP-5.6.24/sapi/cli/php_cli.c:1378
(gdb) 


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 [2016-08-16 22:50 UTC] stas@php.net
-Assigned To: +Assigned To: stas
 [2016-08-16 22:50 UTC] stas@php.net
The fix is in security repo as a29edf505ad1562ed1e468babf0b104d5c2fda9b and in https://gist.github.com/64e09c9dd01524d8c2a9f7e7e0ce32df

please verify
 [2016-08-17 05:57 UTC] stas@php.net
Automatic comment on behalf of stas
Revision: http://git.php.net/?p=php-src.git;a=commit;h=24d741d376905ab21eed17c25dd3ce09a8893f80
Log: Fix bug #72848 - integer overflow in quoted_printable_encode caused heap corruption
 [2016-08-17 05:57 UTC] stas@php.net
-Status: Assigned +Status: Closed
 [2016-08-17 08:23 UTC] stas@php.net
Automatic comment on behalf of stas
Revision: http://git.php.net/?p=php-src.git;a=commit;h=24d741d376905ab21eed17c25dd3ce09a8893f80
Log: Fix bug #72848 - integer overflow in quoted_printable_encode caused heap corruption
 [2016-08-17 09:15 UTC] laruence@php.net
Automatic comment on behalf of stas
Revision: http://git.php.net/?p=php-src.git;a=commit;h=24d741d376905ab21eed17c25dd3ce09a8893f80
Log: Fix bug #72848 - integer overflow in quoted_printable_encode caused heap corruption
 [2016-08-18 11:15 UTC] tyrael@php.net
Automatic comment on behalf of stas
Revision: http://git.php.net/?p=php-src.git;a=commit;h=444314a2919587674c24777e56d29b4040b4fed4
Log: Fix bug #72848 - integer overflow in quoted_printable_encode caused heap corruption
 [2016-10-17 10:09 UTC] bwoebi@php.net
Automatic comment on behalf of stas
Revision: http://git.php.net/?p=php-src.git;a=commit;h=24d741d376905ab21eed17c25dd3ce09a8893f80
Log: Fix bug #72848 - integer overflow in quoted_printable_encode caused heap corruption
 [2017-02-13 01:45 UTC] stas@php.net
-Type: Security +Type: Bug
 
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