[pulseaudio-discuss] [PATCH v2] core-util: Fail if XDG_RUNTIME_DIR belongs to someone else

[Tanu Kaskinen]

On Mon, 2014-09-08 at 13:32 +0200, David Henningsson wrote:
> Usually, PA will use the PULSE_SERVER X11 property instead of using XDG_RUNTIME_DIR,
> so this environment variable does not matter.
> 
> If this property is not available, or if one is using the pacmd cli protocol,
> the client will go ahead and call pa_make_secure_dir on XDG_RUNTIME_DIR/pulse.
> This will either fail (if you're another regular user), or succeed (if you're root).
> Both scenarios are bad - failing will cause the connection to fail, and succeeding
> is even worse, as it can cause *other* connections to fail (as the directory
> ownership has changed).
> 
> Instead fail and complain loudly.
> 
> BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=83007
> Signed-off-by: David Henningsson <david.henningsson at canonical.com>
> ---
>  src/pulsecore/core-util.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> v2: Don't blame systemd anymore. Make error message translatable.
> 
> diff --git a/src/pulsecore/core-util.c b/src/pulsecore/core-util.c
> index d7a95d6..6bb6317 100644
> --- a/src/pulsecore/core-util.c
> +++ b/src/pulsecore/core-util.c
> @@ -1816,6 +1816,14 @@ char *pa_get_runtime_dir(void) {
>      /* Use the XDG standard for the runtime directory. */
>      d = getenv("XDG_RUNTIME_DIR");
>      if (d) {
> +        struct stat st;
> +        if (stat(d, &st) == 0 && st.st_uid != getuid()) {
> +            pa_log(_("XDG_RUNTIME_DIR (%s) is not owned by us (uid %d), but by uid %d!\n"
> +                   "(This could e g happen if you try to connect to a non-root PulseAudio as a root user, over the native protocol. Don't do that.)"),

I'd prefer to not add any line breaks to log messages, because the new
line will not be aligned with the first line, since the first line will
likely have some prefix stuff in it. If you really want to force a long
message to have multiple lines, I think it's better to call pa_log()
multiple times.

Otherwise looks good!

-- 
Tanu