Description:
------------
a heap buffer overflow in zif_sodium_pad


/sapi/cli/php -v
PHP 7.2.10 (cli) (built: Oct  8 2018 05:36:41) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies


 
test@ubuntu:~/php-7.2.10_bak$ ./sapi/cli/php ../crashxxxx.php
```
Warning: ftp_site() expects exactly 2 parameters, 0 given in /home/test/crashxxxx.php on line 6
=================================================================
==17594==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x603000001200 at pc 0x556907c879b1 bp 0x7fff74df9c50 sp 0x7fff74df9c40
READ of size 1 at 0x603000001200 thread T0
    #0 0x556907c879b0 in zif_sodium_pad /home/test/php-7.2.10_bak/ext/sodium/libsodium.c:3407
    #1 0x556908282ad3 in ZEND_DO_ICALL_SPEC_RETVAL_USED_HANDLER /home/test/php-7.2.10/Zend/zend_vm_execute.h:617
    #2 0x556908282ad3 in execute_ex /home/test/php-7.2.10/Zend/zend_vm_execute.h:59750
    #3 0x5569082a8eba in zend_execute /home/test/php-7.2.10/Zend/zend_vm_execute.h:63776
    #4 0x556908005795 in zend_execute_scripts /home/test/php-7.2.10/Zend/zend.c:1496
    #5 0x556907eeddfc in php_execute_script /home/test/php-7.2.10/main/main.c:2590
    #6 0x5569082ae333 in do_cli /home/test/php-7.2.10/sapi/cli/php_cli.c:1011
    #7 0x5569073f4025 in main /home/test/php-7.2.10/sapi/cli/php_cli.c:1404
    #8 0x7f29fae8db96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
    #9 0x5569073f43b9 in _start (/home/test/php-7.2.10_bak/sapi/cli/php+0x44e3b9)

0x603000001200 is located 0 bytes to the right of 32-byte region [0x6030000011e0,0x603000001200)
allocated by thread T0 here:
    #0 0x7f29fea79b50 in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xdeb50)
    #1 0x556907f82488 in __zend_malloc /home/test/php-7.2.10/Zend/zend_alloc.c:2829

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/test/php-7.2.10_bak/ext/sodium/libsodium.c:3407 in zif_sodium_pad
Shadow bytes around the buggy address:
  0x0c067fff81f0: 04 fa fa fa 00 00 00 06 fa fa 00 00 01 fa fa fa
  0x0c067fff8200: 00 00 00 07 fa fa 00 00 00 00 fa fa 00 00 00 06
  0x0c067fff8210: fa fa 00 00 00 07 fa fa 00 00 01 fa fa fa 00 00
  0x0c067fff8220: 00 fa fa fa 00 00 01 fa fa fa fd fd fd fd fa fa
  0x0c067fff8230: 00 00 00 00 fa fa 00 00 00 02 fa fa 00 00 00 00
=>0x0c067fff8240:[fa]fa 00 00 00 00 fa fa 00 00 00 00 fa fa 00 00
  0x0c067fff8250: 00 00 fa fa 00 00 00 00 fa fa 00 00 00 00 fa fa
  0x0c067fff8260: 00 00 00 00 fa fa 00 00 00 00 fa fa 00 00 00 00
  0x0c067fff8270: fa fa 00 00 00 00 fa fa 00 00 00 00 fa fa 00 00
  0x0c067fff8280: 00 00 fa fa 00 00 00 00 fa fa 00 00 00 00 fa fa
  0x0c067fff8290: 00 00 00 00 fa fa 00 00 00 00 fa fa 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==17594==ABORTING
```

Test script:
---------------
test@ubuntu:~/php-7.2.10_bak$ cat ../crashxxxx.php


<?php
function func1(){	return urldecode(preg_quote(uniqid(), gzcompress(gc_mem_caches(-4294967296,-100))));}
function func2(){	return memory_get_peak_usage(func1());}
function test()
{
	return sodium_pad(ftp_site(),func2());
}
test();
?>