PharFileInfo refcount bug

[YuanchengJiang]

Description

The following code:

<?php
$fname = str_replace('\\', '/', __DIR__ . '/files/Structures_Graph-1.0.3.tgz');
$tar = new PharData($fname);
foreach (new RecursiveIteratorIterator($tar) as $file) {
}
$fusion = $file;
$dests = array(
"$sub_dir/..///../copy_copy_variation8.tmp",
"$sub_dir///../*",
"$dirname_with_blank/copy_copy_variation8.tmp"
);
foreach($dests as $dest) {
unlink("$fusion");
}

Resulted in this output:

/home/phpfuzz/WorkSpace/flowfusion/php-src/Zend/zend_string.h:338:2: runtime error: member access within misaligned address 0x7461697261765f79 for type 'zend_string' (aka 'struct _zend_string'), which requires 8 byte alignment
0x7461697261765f79: note: pointer points here
<memory cannot be printed>
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /home/phpfuzz/WorkSpace/flowfusion/php-src/Zend/zend_string.h:338:2 in 

To reproduce:

./php-src/sapi/cli/php  ./test.php

Commit:

commit 5acff0e61dd9a62ddff52bea25d552db45fb32e6
Author: Niels Dossche <[email protected]>
Date:   Tue Feb 11 21:57:50 2025 +0100

    Update NEWS and UPGRADING for zlib flock() support
    
    [ci skip]
    
    Closes GH-17752.

Configurations:

CC="clang-12" CXX="clang++-12" CFLAGS="-DZEND_VERIFY_TYPE_INFERENCE" CXXFLAGS="-DZEND_VERIFY_TYPE_INFERENCE" ./configure --enable-debug --enable-address-sanitizer --enable-undefined-sanitizer --enable-re2c-cgoto --enable-fpm --enable-litespeed --enable-phpdbg-debug --enable-zts --enable-bcmath --enable-calendar --enable-dba --enable-dl-test --enable-exif --enable-ftp --enable-gd --enable-gd-jis-conv --enable-mbstring --enable-pcntl --enable-shmop --enable-soap --enable-sockets --enable-sysvmsg --enable-zend-test --with-zlib --with-bz2 --with-curl --with-enchant --with-gettext --with-gmp --with-mhash --with-ldap --with-libedit --with-readline --with-snmp --with-sodium --with-xsl --with-zip

Operating System:

Ubuntu 20.04 Host, Docker 0599jiangyc/flowfusion:latest

This report is automatically generated by FlowFusion

PHP Version

5acff0e

Operating System

No response

[devnexen]

Hi, can t reproduce this one. Would it be possible to automatically add to your flowfusion reports the following env var :

UBSAN_OPTIONS="print_stacktrace=1" ?

[YuanchengJiang]

@devnexen sure! thank you for letting me know about this option.

/home/phpfuzz/WorkSpace/flowfusion/php-src/Zend/zend_string.h:338:2: runtime error: member access within misaligned address 0x7274532f73656c69 for type 'zend_string' (aka 'struct _zend_string'), which requires 8 byte alignment
0x7274532f73656c69: note: pointer points here
<memory cannot be printed>
    #0 0x2154c22 in zend_string_efree /home/phpfuzz/WorkSpace/flowfusion/php-src/Zend/zend_string.h:338:2
    #1 0x2173b33 in zim_PharFileInfo___destruct /home/phpfuzz/WorkSpace/flowfusion/php-src/ext/phar/phar_object.c:4538:4
    #2 0x3f3494f in zend_call_function /home/phpfuzz/WorkSpace/flowfusion/php-src/Zend/zend_execute_API.c:1021:4
    #3 0x3f3a3de in zend_call_known_function /home/phpfuzz/WorkSpace/flowfusion/php-src/Zend/zend_execute_API.c:1102:23
    #4 0x4be3384 in zend_call_known_instance_method /home/phpfuzz/WorkSpace/flowfusion/php-src/Zend/zend_API.h:860:2
    #5 0x4bde1db in zend_call_known_instance_method_with_0_params /home/phpfuzz/WorkSpace/flowfusion/php-src/Zend/zend_API.h:866:2
    #6 0x4bdd4df in zend_objects_destroy_object /home/phpfuzz/WorkSpace/flowfusion/php-src/Zend/zend_objects.c:194:3
    #7 0x2ab36e4 in spl_filesystem_object_destroy_object /home/phpfuzz/WorkSpace/flowfusion/php-src/ext/spl/spl_directory.c:109:2
    #8 0x4bd13e0 in zend_objects_store_call_destructors /home/phpfuzz/WorkSpace/flowfusion/php-src/Zend/zend_objects_API.c:57:7
    #9 0x3f0f609 in shutdown_destructors /home/phpfuzz/WorkSpace/flowfusion/php-src/Zend/zend_execute_API.c:266:3
    #10 0x4d30dbb in zend_call_destructors /home/phpfuzz/WorkSpace/flowfusion/php-src/Zend/zend.c:1335:3
    #11 0x35298d8 in php_request_shutdown /home/phpfuzz/WorkSpace/flowfusion/php-src/main/main.c:1921:3
    #12 0x4d5c3ae in do_cli /home/phpfuzz/WorkSpace/flowfusion/php-src/sapi/cli/php_cli.c:1144:3
    #13 0x4d5147f in main /home/phpfuzz/WorkSpace/flowfusion/php-src/sapi/cli/php_cli.c:1348:18
    #14 0x7fc96dc99d8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    #15 0x7fc96dc99e3f in __libc_start_main csu/../csu/libc-start.c:392:3
    #16 0x605954 in _start (/home/phpfuzz/WorkSpace/flowfusion/php-src/sapi/cli/php+0x605954)

SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /home/phpfuzz/WorkSpace/flowfusion/php-src/Zend/zend_string.h:338:2 in

[nielsdos]

Simplified:

<?php
$fname = __DIR__.'/ext/phar/tests/tar/files/Structures_Graph-1.0.3.tgz';
$tar = new PharData($fname);
foreach (new RecursiveIteratorIterator($tar) as $file) {
}
unlink("$file");

EDIT: ah if you do this instead, the bug disappears, so the unlink removes some data still in use by file:

$str = "$file";
unset($file);
unlink($str);

[YuanchengJiang]

BTW, the address looks dangerous to me. Is it controllable?

[nielsdos]

It's probably controllable by a subsequent allocation. Question remains how an attacker would do this though but it's not outside the realm of possibility.