UBSan: Negation of PHP_INT_MIN triggers runtime error in streams/memory.c via SplTempFileObject::fseek
Open
Nobody has claimed this yet.
- #20922 by @arshidkv12 — closed without merging
Bug
Category: Streams
Status: Verified
- Dominant language
- C
- Stars
- 40.4k
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Description
Description
The following code:
<?php
$cls = new SplTempFileObject();
$fusion = $cls;
var_dump($fusion->fseek(PHP_INT_MIN, SEEK_END));
Resulted in this output:
/home/phpfuzz/WorkSpace/flowfusion/php-src/main/streams/memory.c:168:45: runtime error: negation of -9223372036854775808 cannot be represented in type 'zend_off_t' (aka 'long'); cast to an unsigned type to negate this value to itself
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /home/phpfuzz/WorkSpace/flowfusion/php-src/main/streams/memory.c:168:45 in
To reproduce:
./php-src/sapi/cli/php ./test.php
Commit:
9ab800ec9b5959dfe3d4cde50f7a27a763d102f8
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 --with-mysqli --with-pdo-mysql --with-pdo-pgsql --with-pgsql --with-sqlite3 --with-pdo-sqlite --with-webp --with-jpeg --with-freetype --enable-sigchild --with-readline --with-pcre-jit --with-iconv
Operating System:
Ubuntu 20.04 Host, Docker 0599jiangyc/flowfusion:latest
This report is automatically generated by FlowFusion
PHP Version
nightly
Operating System
No response
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
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- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start in main/streams/memory.c around line 168 and trace the SplTempFileObject::fseek entry point using the provided PHP_INT_MIN and SEEK_END reproduction in test.php. Run the UBSan command shown in the report; done means this input no longer triggers the negation runtime error.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c, php
- Domain
- backend
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100