Friday, September 27, 2019

Re: firefox: unveil and pledge enhancements [8]

On Fri, 27 Sep 2019 at 15:40:55 +0200, Solene Rapenne wrote:
> On Wed, Sep 25, 2019 at 11:25:59AM -0500, joshua stein wrote:
> > This patchset goes back to files in /etc/firefox for unveil file
> > lists, and goes further and moves the pledge strings to separate
> > files too. This should be the most secure version that is still
> > tweakable at runtime.
> >
> > I switched away from using Firefox's NS_LOCAL_FILE_CONTRACTID/
> > NS_LOCALFILEINPUTSTREAM_CONTRACTID mechanisms to read a file, since
> > they require a lot of internal setup to be done before they can be
> > used (which is otherwise a good thing, because other things later in
> > Firefox shouldn't have raw file access). Instead of those, I'm
> > using the normal C++ API for reading the /etc/firefox files and this
> > way I have been able to move the pledge/unveil calls earlier in the
> > process startup. Unfortunately this also means that I can't
> > dynamically detect the localized ~/Downloads directory, so if you
> > use a different directory, you'll just need to modify the
> > unveil.content and unveil.main files to change it.
> >
> > I tried the $TMPDIR shenanigans with the main process mkdtemp'ing
> > somewhere in $TMPDIR (or /tmp), and then exporting TMPDIR as that
> > directory so that everything else within Firefox uses that
> > subdirectory as its temp directory, allowing /tmp to be removed from
> > the unveil lists and only that subdirectory visible. Unfortunately
> > the first thing to break was our own shm_open() which hard-codes
> > /tmp and doesn't honor $TMPDIR. So that all was ripped out and
> > we're back to full access to /tmp.
> >
> > If the mailing list mangles this again, it's at
> > https://jcs.org/patches/firefox-port-unveil8.diff
> >
>
> running firefox on a fresh account produce an error because .config is
> not there, creating it before starting firefox allow it to run.
>
> $ firefox
> firefox: /etc/firefox/unveil.main: unveil(/home/he-man/.config/dconf, rw) failed: No such file or directory

Oops, I meant to ignore ENOENT in errno, not the return value of
unveil. I'll post a new patch that fixes that and also tries to
"mkdir -p" that dconf path because if it's not there, firefox does a
lot of console spamming.

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