audit: allow unsetting the loginuid (with priv)
If a task has CAP_AUDIT_CONTROL allow that task to unset their loginuid.
This would allow a child of that task to set their loginuid without
CAP_AUDIT_CONTROL. Thus when launching a new login daemon, a
priviledged helper would be able to unset the loginuid and then the
daemon, which may be malicious user facing, do not need priv to function
correctly.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index b55788b..c75d781 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2019,7 +2019,9 @@
if (rc)
goto out;
- sessionid = atomic_inc_return(&session_id);
+ /* are we setting or clearing? */
+ if (uid_valid(loginuid))
+ sessionid = atomic_inc_return(&session_id);
task->sessionid = sessionid;
task->loginuid = loginuid;