Bug #79615 [NEW]: Wrong GIF header written in GD GIFEncode

From: sageptr at gmail dot com Operating system: PHP version: Irrelevant Package: GD related Bug Type: Bug Bug description:Wrong GIF header written in GD GIFEncode Description: ------------ In file https://github.com/php/php-src/blob/master/ext/gd/libgd/gd_gif_out.c#L336, line 336: B |= (Resolution - 1) << 5; Should be: B |= (Resolution - 1) << 4; This bug was fixed in the original libgd: https://github.com/libgd/libgd/commit/db10f301fff50d8f65ebbbedb57b79433c2dc8a3 But still presents in PHP version of GD Test script: --------------- <?php $im = imagecreate(3, 3); // 3x3, 9 colors, 4 bits per pixel for ($x = 0; $x < 3; $x++) for ($y = 0; $y < 3; $y++) imagesetpixel($im, $x, $y, imagecolorallocate($im, $x, $y, 0)); ob_start(); imagegif($im); echo decbin(ord(ob_get_clean()[0xA])); Expected result: ---------------- Should output "10110011" (1 011 0 011, as Resolution bits and BitsPerPixel bits should match) Actual result: -------------- Outputs "11100011" (1 110 0 011, Resolutions bits are shifted 1 bit left) -- Edit bug report at https://bugs.php.net/bug.php?id=79615&edit=1 -- Fix committed: https://bugs.php.net/fix.php?id=79615&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=79615&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=79615&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=79615&r=needscript Try newer version: https://bugs.php.net/fix.php?id=79615&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=79615&r=support Expected behavior: https://bugs.php.net/fix.php?id=79615&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=79615&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=79615&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=79615&r=globals PHP version support discontinued: https://bugs.php.net/fix.php?id=79615&r=phptooold Daylight Savings: https://bugs.php.net/fix.php?id=79615&r=dst IIS Stability: https://bugs.php.net/fix.php?id=79615&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=79615&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=79615&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=79615&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=79615&r=mysqlcfg