Bug #76859 [NEW]: stream_get_line skips data if used with data-generating filter

From: tenzzor at gmail dot com Operating system: Linux PHP version: master-Git-2018-09-11 (Git) Package: Streams related Bug Type: Bug Bug description:stream_get_line skips data if used with data-generating filter Description: ------------ This is happening with stream filters which create more data then they consume. For example, base64_encode, zlib.inflate. The issue is happening because stream_get_line internally calls php_stream_get_record function, which repeatedly calls php_stream_fill_read_buffer until enough data is "accumulated" in the buffer. Problem with that is repeated calls to populate read buffer force reset state of stream->readpos and stream->writepos in case filters exist on the stream. In other words, if on second call to get_record function, buffer holds some data, but does not have delimiter in it and length of data is less then required, then function attempts to put more data into buffer, which is in effect, resets buffer and content is lost. Test script: --------------- <?php $h = fopen('php://temp', 'r+b'); $len = floor(1.5 * 8 * 1024); // 8*1024 == stream->chunk_size. We need a bit more. $data = str_repeat('1', $len); fwrite($h, $data); rewind($h); stream_filter_append($h, 'convert.base64-encode'); $out = ''; while (!feof($h)) { $out .= stream_get_line($h, 1024); } fclose($h); echo $len, ' and ', strlen(base64_decode($out)), PHP_EOL; assert($data == base64_decode($out)); Expected result: ---------------- 12288 and 12288 Actual result: -------------- 12288 and 11520 Warning: assert(): assert($data == base64_decode($out)) failed in /usr/src/app/t3.php on line 17 -- Edit bug report at https://bugs.php.net/bug.php?id=76859&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=76859&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=76859&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=76859&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=76859&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=76859&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=76859&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=76859&r=needscript Try newer version: https://bugs.php.net/fix.php?id=76859&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=76859&r=support Expected behavior: https://bugs.php.net/fix.php?id=76859&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=76859&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=76859&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=76859&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=76859&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=76859&r=dst IIS Stability: https://bugs.php.net/fix.php?id=76859&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=76859&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=76859&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=76859&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=76859&r=mysqlcfg