Re: [Qemu-devel] [PATCH v6 03/29] test-qga: Kill broken and dead QGA_TEST_SIDE_EFFECTING code

[Thomas Huth]

On 01.09.2017 20:03, Eric Blake wrote:
> Back when the test was introduced, in commit 62c39b307, the
> test was set up to run qemu-ga directly on the host performing
> the test, and defaults to limiting itself to safe commands.  At
> the time, it was envisioned that setting QGA_TEST_SIDE_EFFECTING
> in the environment could cover a few more commands, while noting
> the potential danger of those side effects running in the host.
> 
> But this has NEVER been tested: if you enable the environment
> variable, the test WILL fail.  One obvious reason: if you are not
> running as root, you'll probably get a permission failure when
> trying to freeze the file systems, or when changing system time.
> Less obvious: if you run the test as root (wow, you're brave), you
> could end up hanging if the test tries to log things to a
> temporarily frozen filesystem.  But the cutest reason of all: if
> you get past the above hurdles, the test uses invalid JSON in
> test_qga_fstrim() (missing '' around the dictionary key 'minimum'),
> and will thus fail an assertion in qmp_fd().
> 
> Rather than leave this untested time-bomb in place, rip it out.
> Hopefully, as originally envisioned, we can find an opportunity
> to test an actual sandboxed guest where the guest-agent has
> full permissions and will not unduly affect the host running
> the test - if so, 'git revert' can be used if desired, for
> salvaging any useful parts of this attempt.
> 
> Signed-off-by: Eric Blake <address@hidden>
> Reviewed-by: Marc-André Lureau <address@hidden>
> ---
>  tests/test-qga.c | 90 
> --------------------------------------------------------
>  1 file changed, 90 deletions(-)

Reviewed-by: Thomas Huth <address@hidden>