[PHP-DEV] [PATCH] PHP4 and GD, reproduceable SEGFAULT From: Flavien LEBARBE (flebarbe <email protected>)
Date: 04/19/00

Hello,

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.

Flavien Lebarbé. 

-- 
Flavien LEBARBE       OPEN CARE      Support for Freedom
mailto:flebarbe <email protected>           http://www.ocare.com
Tel:+33 141430890                      Fax:+33 141430891

--- gd.c.orig Wed Apr 19 12:27:40 2000 +++ gd.c Wed Apr 19 14:00:48 2000 @@ -460,6 +460,10 @@ fflush(fp); fclose(fp); + if (!im) { + php_error(E_WARNING,"ImageCreateFromPng: %s is not a valid PNG file", fn); + RETURN_FALSE; + } ZEND_REGISTER_RESOURCE(return_value, im, GDG(le_gd)); } /* }}} */ @@ -570,6 +574,10 @@ fflush(fp); fclose(fp); + if (!im) { + php_error(E_WARNING,"ImageCreateFromGif: %s is not a recognized GIF file", fn); + RETURN_FALSE; + } ZEND_REGISTER_RESOURCE(return_value, im, GDG(le_gd)); } /* }}} */ @@ -683,6 +691,10 @@ fflush(fp); fclose(fp); + if (!im) { + php_error(E_WARNING,"ImageCreateFromJPEG: %s is not a recognized JPEG file", fn); + RETURN_FALSE; + } ZEND_REGISTER_RESOURCE(return_value, im, GDG(le_gd)); } /* }}} */ 

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