Re: Browsing and attaching images considered harmful in Linux

[Gustavo Grieco <gustavo.grieco () gmail com>]

2016-07-06 0:41 GMT+02:00  <cve-assign () mitre org>:
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> > I would like to bring the attention of the oss-security list to the
> > existence of many security issues in the gdk-pixbuf library and its
> > dependencies causing a that attaching a corrupted image file in Linux
> > has become a risky business. For instance, there is a read
> > out-of-bounds in librsvg2 (a dependency of gdk-pixbuf used to render
> > svg images), which can be easily triggered if you try to attach a svg
> > in Firefox.
>
> > librsvg2 (2.40.2-1 with debug symbols)
>
> > 1. Download and unpack boom.tar.gz somewhere.
> > 2. gdb --args /usr/lib/firefox/firefox
> > 3. Execute "run" and try to attach (ctrl+o) the svg file inside boom
> > directory in Firefox.
> >
> > Result:
> >
> > Program received signal SIGSEGV, Segmentation fault.
>
> > 0x00007fffbb7a4c0d in rsvg_pattern_fix_fallback
> > (pattern=pattern@entry=0x7ffffffea110) at rsvg-paint-server.c:645
>
> > It is interesting to note that rcx looks controllable:
> >
> > (gdb) x/i $rip
> > => 0x7fffbb7a4c0d <rsvg_pattern_fix_fallback+333>:        testb  $0x4,0xe4(%rcx)
> > (gdb) info registers
> > ...
> > rcx            0xe5e5e5e5e5e5e5e5        -1880844493789993499
> > ...
> >
> > Fortunately, this issue is already solved in the last revision of
> > librsvg2 (AFAIK, this issue has no CVE, so please MITRE assign one if
> > suitable). Nevertheless, I reported such vulnerability to Mozilla more
> > than a month ago hoping that they will disable the svg support in the
> > open/attach widget. After some discussion, it was marked as WONTFIX.
> > While i understand why, i still feel it can be productive to discuss
> > this here.
> >
> > (the same trick can be used to crash Chrome/Chromium, since the code
> > to open/attach an image is almost the same, so this is not a Firefox
> > specific issue)
>
> Use CVE-2016-6163 for this specific "read out-of-bounds in librsvg2 (a
> dependency of gdk-pixbuf used to render svg images)."

Thanks!

> (We cannot assign CVE IDs for the more general topic of "many security
> issues in the gdk-pixbuf library and its dependencies" without
> additional information.)

I only hope to encourage package maintainers to keep gdk-pixbuf and
its dependencies always in the last version.


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