oss-sec mailing list archives
Re: ImageMagick identify "d:" hangs
From: Tavis Ormandy <taviso () google com>
Date: Wed, 28 Sep 2016 11:16:10 -0700
On Tue, Sep 27, 2016 at 7:56 AM, Bob Friesenhahn <bfriesen () simple dallas tx us> wrote:
On Tue, 27 Sep 2016, Jakub Wilk wrote:* Bob Friesenhahn <bfriesen () simple dallas tx us>, 2016-09-27, 08:48:From my own investigations, I used identify -debug all "d:" and see that a temporary file is reported to be created and then the program hangs which no apparent CPU usage.strace tells me that it waits for input on stdin. This is a simpler way to make it "hang": identify -This is what I expected was happening. The main thing to investigate is if the "ImageTragick" patches distributions are using do protect against this possible issue as well.
You know, you reminded me that the pdf and/or the ps delegate probably allows filesystem enumeration via filenameforall, as far as I know that's permitted with -dSAFER. I think that's probably unexpected. For example, if you try to identify a file like this, it will list local usernames on stdout, I guess a real attack would have to encode that in the output somehow, but I only know enough postscript to know i'd rather write bf. Might be a fun exercise for masochistic hackers though. $ cat whatever.jpeg %PDF-1.0 (/home/*) {==} 256 string filenameforall $ identify whatever.jpeg (/home/taviso) identify.im6: Postscript delegate failed `whatever.jpeg': No such file or directory @ error/pdf.c/ReadPDFImage/677. Tavis.
Current thread:
- ImageMagick identify "d:" hangs Bob Friesenhahn (Sep 27)
- Re: ImageMagick identify "d:" hangs Jakub Wilk (Sep 27)
- Re: ImageMagick identify "d:" hangs Bob Friesenhahn (Sep 27)
- Re: ImageMagick identify "d:" hangs Tavis Ormandy (Sep 28)
- Re: ImageMagick identify "d:" hangs Tavis Ormandy (Sep 28)
- Re: ImageMagick identify "d:" hangs Tavis Ormandy (Sep 28)
- Re: ImageMagick identify "d:" hangs Bob Friesenhahn (Sep 28)
- Re: ImageMagick identify "d:" hangs Tavis Ormandy (Sep 28)
- Re: ImageMagick identify "d:" hangs Florian Weimer (Sep 28)
- Re: ImageMagick identify "d:" hangs Bob Friesenhahn (Sep 27)
- Re: ImageMagick identify "d:" hangs Jakub Wilk (Sep 27)
- Re: ImageMagick identify "d:" hangs Florian Weimer (Sep 28)
- Re: ImageMagick identify "d:" hangs Tavis Ormandy (Sep 29)
- Re: ImageMagick identify "d:" hangs Tavis Ormandy (Sep 29)
- Re: ImageMagick identify "d:" hangs Tavis Ormandy (Sep 30)
- Re: ImageMagick identify "d:" hangs Florian Weimer (Sep 30)