bug#38422: .png files in /gnu/store with executable permissions (555)

[Bengt Richter <bokr@bokr.com>]

Hi Ricardo,

On +2019-11-29 10:49:06 +0100, Ricardo Wurmus wrote:
> 
> Bengt Richter <bokr@bokr.com> writes:
> 
> > $ find /gnu -type f -perm /111 -iname '*png'|xargs stat -c '%a %A %N'|cut -d '-' -f5,6,7,8|less|uniq -c|less
> > --8<---------------cut here---------------start------------->8---
> >       1 x '/gnu/store/.links/1s94fymqj8xba55rg8xbdni9a215kxsxkddyh2qyb7y6fl7srpng'
> >       1 x '/gnu/store/.links/05dsk06ffdwgjdqgsy03zhnsrcd44yyi8ylk9qyb1a3n89aplpng'
> >      97 x '/gnu/store/jf7i57glqykwgm1k7zb5k8x6f1yd47l8-faba-icon-theme
> >       1 x '/gnu/store/k83hj06qj142xv6rqpfh3mcdf3149q09-gd-2.2.5/bin/gdparttopng'
> >       1 x '/gnu/store/k83hj06qj142xv6rqpfh3mcdf3149q09-gd-2.2.5/bin/gdtopng'
> >       1 x '/gnu/store/k83hj06qj142xv6rqpfh3mcdf3149q09-gd-2.2.5/bin/webpng'
> >       1 x '/gnu/store/k83hj06qj142xv6rqpfh3mcdf3149q09-gd-2.2.5/bin/gd2topng'
> >       1 x '/gnu/store/x9c77i6r5fmarslij6ng81awgrxblplm-texlive-bin-20180414/bin/dvipng'
> >   34143 x '/gnu/store/yg6skr4v6vnj04rm5k9h3pa81mjivba7-moka-icon-theme
> >       1 x '/gnu/store/7mxkdn6cp7x8sac49p2g80qw5j1aavi3-texlive-20180414/bin/dvipng'
> >      62 x '/gnu/store/6d79d8za76pj5f2flhckpmdvdgqhqxaa-docbook-xsl-1.79.1/xml/xsl/docbook
> >       1 x '/gnu/store/azd3rg350gjkgzvzps3s4j3kpz5kxh57-texlive-bin-20180414/bin/dvipng'
> >       1 x '/gnu/store/9w1hi2hr4zczc5jd5r2xmff9zf4gwc1n-texlive-union-49435/bin/dvipng'
> >       1 x '/gnu/store/5hv33gy8w247v3dcf4dfa8p0ijkmiz5x-gd-2.2.5/bin/gdparttopng'
> >       1 x '/gnu/store/5hv33gy8w247v3dcf4dfa8p0ijkmiz5x-gd-2.2.5/bin/gdtopng'
> >       1 x '/gnu/store/5hv33gy8w247v3dcf4dfa8p0ijkmiz5x-gd-2.2.5/bin/webpng'
> >       1 x '/gnu/store/5hv33gy8w247v3dcf4dfa8p0ijkmiz5x-gd-2.2.5/bin/gd2topng'
> >       1 x '/gnu/store/9jgmsnx36wv8ymgalwd1zlmq3z34bqf0-gd-2.2.5/bin/gdparttopng'
> >       1 x '/gnu/store/9jgmsnx36wv8ymgalwd1zlmq3z34bqf0-gd-2.2.5/bin/gdtopng'
> >       1 x '/gnu/store/9jgmsnx36wv8ymgalwd1zlmq3z34bqf0-gd-2.2.5/bin/webpng'
> >       1 x '/gnu/store/9jgmsnx36wv8ymgalwd1zlmq3z34bqf0-gd-2.2.5/bin/gd2topng'
> >
> > --8<---------------cut here---------------end--------------->8---
> 
> Maybe I’m missing something, but none of the above are PNGs.
> Most of them are executables, others are directories, so having them
> executable is expected.
> 
> Did I misunderstand?
>

No, you just didn't see it ;-)
┌───────────────────────────────────────────────────────────────────────────────────────────────┐
│ Sorry I didn't highlight well enough that I had trimmed off the full paths that ended in .png │
│ in what you snipped out above the above (see box below):                                      │
└───────────────────────────────────────────────────────────────────────────────────────────────┘

--8<----(the part you snipped out)-----------cut here---------------start------------->8---
Hi Guix,

I was wanting to check on some executable files in the store,
and happened to see some executable .png files ;-/

I suspect they came in when I was playing with icecat
and let it load  a "theme", but I am not sure some didn't
also happen trying to get firefox radio buttons to work ;-/

Anyway, does anyone else get 555 permissions on files like these?
┌───────────────────────────────────────────────────────────────────────────────────────────┐
│ These are all *.png files with 555 permissons, but I trimmed back to see common prefixes. │
│ Obviously the moka-con-theme was most of it, but also faba and docbook look iffy.         │
└───────────────────────────────────────────────────────────────────────────────────────────┘

Is this zero-day stuff with a nasty somewhere, waiting for referencing by another nasty, or am I being paranoid?
What is the safe way to detoxify this mess? I know I shouldn't directly chmod anything in store, right?

The icecat discussion got moved to mozilla, but in case someone else did whatever I did,
I thought I'd post a heads-up here.
I'll try to cc Mark :)
--8<----(the part you snipped out)-----------cut here---------------end--------------->8---


Note the cut -d '-' etc from above
--8<---------------cut here---------------start------------->8---
> > $ find /gnu -type f -perm /111 -iname '*png'|xargs stat -c '%a %A %N'|cut -d '-' -f5,6,7,8|less|uniq -c|less
--8<---------------cut here---------------end--------------->8---

I thought the 34143 moka-icon-theme items looked especially iffy, being so many:
--8<---------------cut here---------------start------------->8---
> >   34143 x '/gnu/store/yg6skr4v6vnj04rm5k9h3pa81mjivba7-moka-icon-theme
--8<---------------cut here---------------end--------------->8---

So let's not cut that tail and just grab some of those moka-icon-theme items full length:
$ find /gnu -type f -perm /111 -iname '*png'|xargs stat -c '%a %A %N'|grep moka-icon-theme|head
--8<---------------cut here---------------start------------->8---
555 -r-xr-xr-x '/gnu/store/yg6skr4v6vnj04rm5k9h3pa81mjivba7-moka-icon-theme-5.4.0/share/icons/Moka/64x64@2x/emblems/emblem-insync-synced.png'
555 -r-xr-xr-x '/gnu/store/yg6skr4v6vnj04rm5k9h3pa81mjivba7-moka-icon-theme-5.4.0/share/icons/Moka/64x64@2x/emblems/emblem-synchronizing.png'
555 -r-xr-xr-x '/gnu/store/yg6skr4v6vnj04rm5k9h3pa81mjivba7-moka-icon-theme-5.4.0/share/icons/Moka/64x64@2x/emblems/emblem-insync-synced-callbacks-active.png'
555 -r-xr-xr-x '/gnu/store/yg6skr4v6vnj04rm5k9h3pa81mjivba7-moka-icon-theme-5.4.0/share/icons/Moka/64x64@2x/emblems/emblem-insync-syncing.png'
555 -r-xr-xr-x '/gnu/store/yg6skr4v6vnj04rm5k9h3pa81mjivba7-moka-icon-theme-5.4.0/share/icons/Moka/64x64@2x/emblems/emblem-dropbox-uptodate.png'
555 -r-xr-xr-x '/gnu/store/yg6skr4v6vnj04rm5k9h3pa81mjivba7-moka-icon-theme-5.4.0/share/icons/Moka/64x64@2x/emblems/emblem-readonly.png'
555 -r-xr-xr-x '/gnu/store/yg6skr4v6vnj04rm5k9h3pa81mjivba7-moka-icon-theme-5.4.0/share/icons/Moka/64x64@2x/emblems/emblem-important.png'
555 -r-xr-xr-x '/gnu/store/yg6skr4v6vnj04rm5k9h3pa81mjivba7-moka-icon-theme-5.4.0/share/icons/Moka/64x64@2x/emblems/emblem-danger.png'
555 -r-xr-xr-x '/gnu/store/yg6skr4v6vnj04rm5k9h3pa81mjivba7-moka-icon-theme-5.4.0/share/icons/Moka/64x64@2x/emblems/emblem-web.png'
555 -r-xr-xr-x '/gnu/store/yg6skr4v6vnj04rm5k9h3pa81mjivba7-moka-icon-theme-5.4.0/share/icons/Moka/64x64@2x/emblems/emblem-symbolic-link.png'
--8<---------------cut here---------------end--------------->8---

Some executables ending in png are legit, like conversion programs from something to .png format.

> -- 
> Ricardo
> 

PS. Thinking about it, I'm pretty sure I used normal guix install ... yes:

--8<----(555s were in source tarball)-----------cut here---------------start------------->8---
$ guix package -I|grep -i moka
moka-icon-theme 5.4.0   out     /gnu/store/yg6skr4v6vnj04rm5k9h3pa81mjivba7-moka-icon-theme-5.4.0
$ mkdir ~/my-roots
$ guix build -r ~/my-roots/moka -S moka-icon-theme
substitute: updating substitutes from 'https://ci.guix.gnu.org'... 100.0%
67.4 MB will be downloaded:
   /gnu/store/vd3l2qbmdw0i9v9knqjm3q42sfwli2nl-moka-icon-theme-5.4.0.tar.gz
substituting /gnu/store/vd3l2qbmdw0i9v9knqjm3q42sfwli2nl-moka-icon-theme-5.4.0.tar.gz...
downloading from https://ci.guix.gnu.org/nar/vd3l2qbmdw0i9v9knqjm3q42sfwli2nl-moka-icon-theme-5.4.0.tar.gz...
 moka-icon-theme-5.4.0.tar.gz  64.3MiB                                                                                1.5MiB/s 00:44 [##################] 100.0%

/gnu/store/vd3l2qbmdw0i9v9knqjm3q42sfwli2nl-moka-icon-theme-5.4.0.tar.gz
$ lsc ~/my-roots/*
                 72 2019-11-29 03:53:27 [@] /home/bokr/my-roots/moka -> /gnu/store/vd3l2qbmdw0i9v9knqjm3q42sfwli2nl-moka-icon-theme-5.4.0.tar.gz
$ tar -tzvf ~/my-roots/moka|egrep -m5 'png$'
lrwxrwxrwx root/root         0 2018-06-16 09:06 moka-icon-theme-5.4.0/Moka/16x16/actions/exit.png -> system-log-out.png
lrwxrwxrwx root/root         0 2018-06-16 09:06 moka-icon-theme-5.4.0/Moka/16x16/actions/gnome-lockscreen.png -> system-lock-screen.png
lrwxrwxrwx root/root         0 2018-06-16 09:06 moka-icon-theme-5.4.0/Moka/16x16/actions/gnome-logout.png -> system-log-out.png
lrwxrwxrwx root/root         0 2018-06-16 09:06 moka-icon-theme-5.4.0/Moka/16x16/actions/gnome-run.png -> system-run.png
lrwxrwxrwx root/root         0 2018-06-16 09:06 moka-icon-theme-5.4.0/Moka/16x16/actions/gnome-session-reboot.png -> system-restart.png

Oops, those were links, let's try again:

$ tar -tzvf ~/my-roots/moka|egrep -m5 '^[^l].*png$'
-rwxrwxr-x root/root       633 2018-06-16 09:06 moka-icon-theme-5.4.0/Moka/16x16/actions/system-lock-screen.png
-rwxrwxr-x root/root       537 2018-06-16 09:06 moka-icon-theme-5.4.0/Moka/16x16/actions/system-log-out.png
-rwxrwxr-x root/root       554 2018-06-16 09:06 moka-icon-theme-5.4.0/Moka/16x16/actions/system-restart.png
-rwxrwxr-x root/root       549 2018-06-16 09:06 moka-icon-theme-5.4.0/Moka/16x16/actions/system-run.png
-rwxrwxr-x root/root       544 2018-06-16 09:06 moka-icon-theme-5.4.0/Moka/16x16/actions/system-shutdown.png
--8<----(555s were in source tarball)-----------cut here---------------end--------------->8---

-- 
Regards,
Bengt Richter