Bug #69706 [Fbk->NoF]: getimagesize() can fail if the underlying stream doensn't support seeking

Edit report at https://bugs.php.net/bug.php?id=69706&edit=1 ID: 69706 Updated by: php-bugs@lists.php.net Reported by: deviantintegral at gmail dot com Summary: getimagesize() can fail if the underlying stream doensn't support seeking -Status: Feedback +Status: No Feedback Type: Bug Package: GetImageSize related Operating System: Any PHP Version: 5.6.9 Assigned To: cmb Private report: N New Comment: No feedback was provided. The bug is being suspended because we assume that you are no longer experiencing the problem. If this is not the case and you are able to provide the information that was requested earlier, please do so and change the status of the bug back to "Re-Opened". Thank you. Previous Comments: ------------------------------------------------------------------------ [2020-04-02 11:25:32] cmb@php.net For SEEK_CUR and positive offsets, non-seekable streams are supposed to be read (discarding what was written). So if you can still reproduce this issue with any of the actively supported PHP versions[1], please provide a minimal self-contained reproduce script. [1] <https://www.php.net/supported-versions.php> ------------------------------------------------------------------------ [2015-05-25 18:29:08] deviantintegral at gmail dot com Description: ------------ I've verified this is an issue on PHP 5.4, 5.6, and statically on the master branch. The AWS SDK (https://aws.amazon.com/sdk-for-php/) includes a stream wrapper that by default does not support seeking on files backed by S3. Calling getimagesize() on an image can fail if php_skip_variable() is called. I've seen this happen with images that specify the "Image Quality" EXIF tag, which is the M_APP15 constant in ext/standard/image.c. The stream documentation states that seeking is not required to be supported by stream wrappers, and it's not clear that getimagesize() needs seeking to work properly. I see two ways to improve this: * Log a notice if php_skip_variable() tries to seek on an unseekable stream. That would have saved me a ton of time tracing this with GDB. * Or, if a stream is not seekable, copy the file to the temporary file system and fetch metadata from there. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=69706&edit=1