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>

1 files changed, 0 insertions, 13 deletions

diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index d214cd073a58..c0d148bd7a5c 100644
--- 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;