PHP 4.0 Bug #4201: ImageCreateFromPNG("/dev/null") crashes (Segfault)

From: flebarbe@ocare.com Operating system: Linux PHP version: 4.0 Latest CVS (20/04/2000) PHP Bug Type: Reproduceable crash Bug description: ImageCreateFromPNG("/dev/null") crashes (Segfault) With gd and jpeg enabled in PHP4b4. Here's a simple test script that crashes PHP4-cvs : <?php ImageCreateFromJPEG("/dev/null"); ImageCreateFromPNG("/dev/null"); ?> It crashes at shutdown time. I backtraced it to the following : (from gd.c, line 688) : im = gdImageCreateFromJpeg(fp); fflush(fp); fclose(fp); ZEND_REGISTER_RESOURCE(return_value, im, GDG(le_gd)); } If gdImageCreateFromJpeg cannot interpret the file to create the image, it returns NULL. So, NULL is registered as a resource to free. Then, at shutdown time, 'gdImageDestroy' is called with NULL as argument, and it crashes. The patch I attach to this message does the folloing: 1) Issue a warning if gdImageCreateFromJPEG returns NULL, 2) Returns false to the script (so that the programmer can test it), 3) Prevents 'im' to be registered as a resource to destroy. The situation is exactly the same for PNG and GIF.