audit: don't attempt to lookup PIDs when changing PID filtering audit rules

Commit f1dc4867 ("audit: anchor all pid references in the initial pid
namespace") introduced a find_vpid() call when adding/removing audit
rules with PID/PPID filters; unfortunately this is problematic as
find_vpid() only works if there is a task with the associated PID
alive on the system.  The following commands demonstrate a simple
reproducer.

	# auditctl -D
	# auditctl -l
	# autrace /bin/true
	# auditctl -l

This patch resolves the problem by simply using the PID provided by
the user without any additional validation, e.g. no calls to check to
see if the task/PID exists.

Cc: stable@vger.kernel.org # 3.15
Cc: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>

diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index d214cd073a58001a6af0a99275b435552116928e..c0d148bd7a5cdf20a27b7cbd8d6c40c218c73b8b 100644 (file)
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -444,19 +444,6 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
                        f->val = 0;
                }
 
-               if ((f->type == AUDIT_PID) || (f->type == AUDIT_PPID)) {
-                       struct pid *pid;
-                       rcu_read_lock();
-                       pid = find_vpid(f->val);
-                       if (!pid) {
-                               rcu_read_unlock();
-                               err = -ESRCH;
-                               goto exit_free;
-                       }
-                       f->val = pid_nr(pid);
-                       rcu_read_unlock();
-               }
-
                err = audit_field_valid(entry, f);
                if (err)
                        goto exit_free;