integer overflow in imagepng

Description

The following code:

<?php
try {
$exp = imagecreate(100, 100);
imageresolution($exp, 71, 0x80000000);
imagepng($exp, $filename);
} catch (\Throwable $_ffl_e) {}

Resulted in this output:

/home/fuzz/WorkSpace/fusion-fuzz/projects/php/php-src/ext/gd/libgd/gd_png.c:556:54: runtime error: 8.45466e+10 is outside the range of representable values of type 'unsigned int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /home/fuzz/WorkSpace/fusion-fuzz/projects/php/php-src/ext/gd/libgd/gd_png.c:556:54 in 

To reproduce:

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

Commit:

dc807bca6d2ea6463748b7398f7910841f96b7ea

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 bug was found by fusion-fuzz

PHP Version

nightly

Operating System

No response

ext/gd/libgd/gd_png.c の 556 行目付近から始め、示されている UBSan 設定で提供された PHP スクリプトを使って報告を再現します。imageresolution の値がどのように imagepng に到達するかを追跡します。再現コードが integer-conversion の未定義動作を報告しなくなり、そのケースの回帰テストによるカバレッジがあれば完了です。