Apport hook prompts 3 times for password

Unfortunately, in looking into this it's not easy to fix, at least not in the apport hook itself.

The code in question is:
 report['GdmLog'] = root_collect_file_contents('/var/log/gdm/:0.log')
        report['GdmLog1'] = root_collect_file_contents('/var/log/gdm/:0.log.1')
        report['GdmLog2'] = root_collect_file_contents('/var/log/gdm/:0.log.2')

Each of the root_collect_file_contents() calls essentially calls and return root_command_output(['cat', path]). root_command_output() is one of the stock apport lib routines.

So the question is, why isn't root_command_output() caching the sudo permission from one call to the next?

@Martin, do you have a suggestion for how to better attach three files as separate apport items without incurring three password prompts?

Indeed it works when running without $DISPLAY, i. e. apport calls sudo directly. But it doesn't seem to cache credentials when using gksu, as this creates new PTYs (to run sudo in) every time.

We could provide a new API root_commands_output to accept a keyname -> [command list] and slurp in all command outputs in one go. The xorg hook could then use that.

That seems to be a rather interesting gksu bug or misbehaviour: "gksu whoami" does cache the password through sudo, but "gksu whoami > /tmp/o" doesn't. So the output redirection breaks this somehow.

(Note that "sudo whoami > /tmp/o" just works fine).

OK, this is definitively gksu breakage when searchign for the password prompt. Let's fix it at the proper place.

The root cause of this is sudo itself, after all. It seems to check if any of stdin/out/err is a real PTY and grab the ticket if available. But if all of stdin/out/err are redirected, it doesn't respect the sudo tickets any more either:

  cat | /usr/bin/sudo whoami 2>&1 |cat

always asks for a password. libgksu needs to provides stdin for the password, and redirect stderr for checking if the password was correct. If you now additionally redirect stdout as well, there is no fd left to check the PTY with.

There seems to be another mode with "forkpty()", I'll check this.

So, we can't fix that in sudo or libgksu; with "forkpty" it's even worse, as a new TTY will be allocated every time.

Restoring back to xorg (for updating the hook) and apport (for providing better API).

On Tue, Feb 15, 2011 at 04:15:18PM -0000, Martin Pitt wrote:
> Restoring back to xorg (for updating the hook) and apport (for providing
> better API).

What is your recommendation for how we can work around this in the hook?
(Or should I wait for the better API?)

Bryce Harrington [2011-02-15 20:16 -0000]:
> What is your recommendation for how we can work around this in the hook?

You need to cat all gdm log files at once, and then pick them apart
yourself (or just store them in one key).

I have to think about how to run multiple programs and store their
individual outputs in one go. I have an idea, but it will take some
more effort to implement. I hope I can get to that in the next week,
though.

--
Martin Pitt | http://www.piware.de
Ubuntu Developer (www.ubuntu.com) | Debian Developer (www.debian.org)

Fixed upstream. I added a new method

def attach_root_command_outputs(report, command_map):
    '''Execute multiple commands as root and put their outputs into report.

    command_map is a keyname -> 'shell command' dictionary with the commands to
    run. They are all run through /bin/sh, so you need to take care of shell
    escaping yourself. To include stderr output of a command, end it with
    "2>&1".

    Just like root_command_output() this will use gksu, kdesudo, or sudo for
    gaining root privileges, depending on the running desktop environment.

    This is preferrable to using root_command_output() multiple times, as that
    will ask for the password every time.
    '''

This patch against the current hook uses the new API. Bryce, as I can't commit to the xorg git, would you mind committing/uploading this yourself? Thanks!

This bug was fixed in the package apport - 1.18-0ubuntu1

---------------
apport (1.18-0ubuntu1) natty; urgency=low

  [ Martin Pitt ]
  * New upstream release:
    - Ensure that symptom scripts define a run() function, and don't show them
      if not.
    - Do not show symptom scripts which start with an underscore. These can be
      used for private libraries for the actual symptom scripts.
    - Update bash completion. Thanks Philip Muškovac.
    - etc/default/apport: Remove obsolete "maxsize" setting. (LP: #719564)
    - Remove explicit handling of KDE *.ui files in setup.py, as
      python-distutils-extra 2.24 fixes this. Bump version check.
    - hookutils.py: Add attach_root_command_outputs() to run several commands
      at once. This avoids asking for the password several times.
      (LP: #716595)
  * debian/apport.postinst: Add missing debhelper token.
  * debian/rules: Drop dump_acpi_tables.py chmod workaround, it's upstream now
    and has the proper permissions.
  * Add etc/apport/blacklist.d/apport and drop the creation of it in
    /debian/rules. This is easier to maintain and more obvious. Also move
    README.blacklist from python-apport to apport, it fits better there.
  * etc/apport/blacklist.d/apport: Add the binaries of nspluginwrapper, as we
    can't do anything about them anyway. (LP: #717468)

  [ Brian Murray ]
  * data/package-hooks/source_linux.py: Properly set regression-release tag if
    the reporter chooses "I do not know".
 -- Martin Pitt <email address hidden> Wed, 16 Feb 2011 14:29:36 +0100

This bug was fixed in the package xorg - 1:7.6~3ubuntu5

---------------
xorg (1:7.6~3ubuntu5) natty; urgency=low

  * apport/source_xorg.py:
    - Add 'locale' information (for keyboards)
    - Drop 'glxinfo' since it's been demoted to universe (LP: #714784)
    - Switch to new attach_root_command_outputs() call. Prevents prompting
      for password 3 times for 3 gdm files (thanks Pitti!) (LP: #716595)
 -- Bryce Harrington <email address hidden> Thu, 17 Feb 2011 11:42:58 -0800

I still get this sort of behaviour - I was asked once for a password for the video data and again for the data for my kernel. This is on 12.04 when Compiz crashed.

On Thu, Feb 09, 2012 at 06:27:11PM -0000, Avi Greenbury wrote:
> I still get this sort of behaviour - I was asked once for a password for
> the video data and again for the data for my kernel. This is on 12.04
> when Compiz crashed.

The way apport works, it can't hold onto the root password between
function calls. This bug was "solved" by attaching all three gdm files
in one function call.

However, the display manager data and the kernel data require separate
function calls, and since both require sudo to do so, you get prompted
twice. Still an undesired behavior, but not this bug.