[php-src] Issue #19094: SEGV _zend_class_iterator_funcs

Issue: https://github.com/php/php-src/issues/19094 Author: YuanchengJiang ### Description The following code: ```php <?php $cls = new MultipleIterator(); $fusion = $cls; class Canary extends stdClass { } $canary = new Canary('canary'); $fusion[$canary] = $canary; try {$cls->key();} catch (Exception $e) { echo($e); } ``` Resulted in this output: ``` /home/phpfuzz/WorkSpace/flowfusion/php-src/ext/spl/spl_observer.c:1290:77: runtime error: member access within null pointer of type 'zend_class_iterator_funcs' (aka 'struct _zend_class_iterator_funcs') SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /home/phpfuzz/WorkSpace/flowfusion/php-src/ext/spl/spl_observer.c:1290:77 in ``` To reproduce: ``` ./php-src/sapi/cli/php ./test.php ``` Commit: ``` b43a7ac0e776ef3879fb236cd3f4efa82ba2bb3b ``` 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](https://github.com/php/flowfusion)* ### PHP Version ```plain b43a7ac0e776ef3879fb236cd3f4efa82ba2bb3b ``` ### Operating System _No response_