From a12ac49f0dfc4295e039eafaaf70db2f3c27662a Mon Sep 17 00:00:00 2001 From: Philip Withnall Date: Tue, 2 Jun 2015 16:19:51 +0100 Subject: [PATCH] sessionmonitor-systemd: Use sd_uid_get_state() to check session activity MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Instead of using sd_pid_get_session() then sd_session_is_active() to determine whether the user is active, use sd_uid_get_state() directly. This gets the maximum of the states of all the user’s sessions, rather than the state of the session containing the subject process. Since the user is the security boundary, this is fine. This change is necessary for `systemd --user` sessions, where most user code will be forked off user@.service, rather than running inside the logind session (whether that be a foreground/active or background/online session). Policy-wise, the change is from checking whether the subject process is in an active session; to checking whether the subject process is owned by a user with at least one active session. https://bugs.freedesktop.org/show_bug.cgi?id=76358 --- .../polkitbackendsessionmonitor-systemd.c | 33 +++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-) diff --git a/src/polkitbackend/polkitbackendsessionmonitor-systemd.c b/src/polkitbackend/polkitbackendsessionmonitor-systemd.c index 9995f87..4ed7a04 100644 --- a/src/polkitbackend/polkitbackendsessionmonitor-systemd.c +++ b/src/polkitbackend/polkitbackendsessionmonitor-systemd.c @@ -389,6 +389,37 @@ gboolean polkit_backend_session_monitor_is_session_active (PolkitBackendSessionMonitor *monitor, PolkitSubject *session) { - return sd_session_is_active (polkit_unix_session_get_session_id (POLKIT_UNIX_SESSION (session))); + const char *session_id; + char *state; + uid_t uid; + gboolean is_active = FALSE; + + session_id = polkit_unix_session_get_session_id (POLKIT_UNIX_SESSION (session)); + + g_debug ("Checking whether session %s is active.", session_id); + + /* Check whether *any* of the user's current sessions are active. */ + if (sd_session_get_uid (session_id, &uid) < 0) + goto fallback; + + g_debug ("Session %s has UID %u.", session_id, uid); + + if (sd_uid_get_state (uid, &state) < 0) + goto fallback; + + g_debug ("UID %u has state %s.", uid, state); + + is_active = (g_strcmp0 (state, "active") == 0); + free (state); + + return is_active; + +fallback: + /* Fall back to checking the session. This is not ideal, since the user + * might have multiple sessions, and we cannot guarantee to have chosen + * the active one. + * + * See: https://bugs.freedesktop.org/show_bug.cgi?id=76358. */ + return sd_session_is_active (session_id); } -- 2.1.0