Bug #74175 [NEW]: php_random_bytes() failing with built on system where SYS_getrandom is defined

From: lbarnaud@php.net Operating system: Linux PHP version: 7.1.2 Package: Unknown/Other Function Bug Type: Bug Bug description:php_random_bytes() failing with built on system where SYS_getrandom is defined Description: ------------ - Built PHP on a system where the SYS_getrandom macro is defined - Ran the executable on a Kernel that doesn't implement this syscall - php_random_bytes() is unable to generate random bytes (always returns FAILURE) I stumbled upon this issue by running a "php:7-alpine" Docker container (from https://hub.docker.com/_/php/) on a Debian 8 with a 3.16 kernel. The getrandom syscall is apparently implemented in linux 3.17. The problem became visible when session_regenerate_id() failed with the following error: Failed to create new session ID: user (path: /sessions) Which I traced to php_random_bytes() returning FAILURE. Expected result: ---------------- php_random_bytes() could fallback to other methods, such as readon /dev/urandom, when the "getrandom" syscall is not implemented by the kernel. Actual result: -------------- php_random_bytes() calls syscall(SYS_getrandom, ...). This returns -1, with errno=38. php_random_bytes() returns FAILURE. -- Edit bug report at https://bugs.php.net/bug.php?id=74175&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=74175&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=74175&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=74175&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=74175&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=74175&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=74175&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=74175&r=needscript Try newer version: https://bugs.php.net/fix.php?id=74175&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=74175&r=support Expected behavior: https://bugs.php.net/fix.php?id=74175&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=74175&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=74175&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=74175&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=74175&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=74175&r=dst IIS Stability: https://bugs.php.net/fix.php?id=74175&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=74175&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=74175&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=74175&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=74175&r=mysqlcfg