Bug #78987 [NEW]: Memory problems running finfo::buffer with PHP_CLI

From: jhhillie at amazon dot com Operating system: Ubuntu PHP version: 7.4Git-2019-12-18 (Git) Package: Performance problem Bug Type: Bug Bug description:Memory problems running finfo::buffer with PHP_CLI Description: ------------ When calling finfo::buffer() with a crafted string, PHP tries to allocate an insane amount of memory to do so. I found a similar bug here - https://bugs.php.net/bug.php?id=68819 I suspect the bug may have been re-introduced at some stage during newer versions. 1) I tested it on the version my customer had been using - v7.0.33 (doesn't work) 2) I then tested on the latest php version - v7.4.0 (doesn't work) 3) Testing on an older version - v5.4.16 it works perfectly. Test script: --------------- Generated a random file of 300MB using: $ sudo fallocate -l 300M test-file The script used: <?php $content = file_get_contents('test-file', true); $fileInfo = new \finfo(FILEINFO_MIME_TYPE); var_dump($fileInfo->buffer($content)); ?> Expected result: ---------------- To provide the file metadata (I know there are other ways to do this): string(19) "application/x-empty" Actual result: -------------- PHP Warning: finfo::buffer(): Failed identify data 12:cannot allocate 2516582408 bytes (Cannot allocate memory)application/octet-stream in php shell code on line 1 bool(false) -- Edit bug report at https://bugs.php.net/bug.php?id=78987&edit=1 -- Fix committed: https://bugs.php.net/fix.php?id=78987&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=78987&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=78987&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=78987&r=needscript Try newer version: https://bugs.php.net/fix.php?id=78987&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=78987&r=support Expected behavior: https://bugs.php.net/fix.php?id=78987&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=78987&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=78987&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=78987&r=globals PHP version support discontinued: https://bugs.php.net/fix.php?id=78987&r=phptooold Daylight Savings: https://bugs.php.net/fix.php?id=78987&r=dst IIS Stability: https://bugs.php.net/fix.php?id=78987&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=78987&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=78987&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=78987&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=78987&r=mysqlcfg