Bug #74240 [NEW]: deflate_add can allocate too much memory

From: matt at bonneau dot net Operating system: All PHP version: master-Git-2017-03-13 (Git) Package: Zlib related Bug Type: Bug Bug description:deflate_add can allocate too much memory Description: ------------ deflate_add can grossly overestimate memory needed for the output buffer. This is more likely with highly compressable data. The allocations are roughly equal to the total bytes processed by deflate_add and can cause PHP to run out of memory. Test script: --------------- $deflator = deflate_init(ZLIB_ENCODING_RAW); $bytes = str_repeat("*", 65536); // if you use random bytes this usually can run forever // because they are not very compressable //$bytes = openssl_random_pseudo_bytes(65536); // this crashes after about 500 iterations if PHP is // configured for 64M for ($i = 0; $i < 100000; $i++) { echo "$i\n"; $output = deflate_add( $deflator, $bytes, ZLIB_SYNC_FLUSH ); } -- Edit bug report at https://bugs.php.net/bug.php?id=74240&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=74240&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=74240&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=74240&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=74240&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=74240&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=74240&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=74240&r=needscript Try newer version: https://bugs.php.net/fix.php?id=74240&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=74240&r=support Expected behavior: https://bugs.php.net/fix.php?id=74240&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=74240&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=74240&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=74240&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=74240&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=74240&r=dst IIS Stability: https://bugs.php.net/fix.php?id=74240&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=74240&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=74240&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=74240&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=74240&r=mysqlcfg