[PATCH 3.17 57/73] audit: dont attempt to lookup PIDs when changing PID filtering audit rules

From: Greg Kroah-Hartman
Date: Tue Jan 06 2015 - 21:28:31 EST


3.17-stable review patch. If anyone has any objections, please let me know.

------------------

From: Paul Moore <pmoore@xxxxxxxxxx>

commit 3640dcfa4fd00cd91d88bb86250bdb496f7070c0 upstream.

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: Richard Guy Briggs <rgb@xxxxxxxxxx>
Signed-off-by: Paul Moore <pmoore@xxxxxxxxxx>
Acked-by: Eric Paris <eparis@xxxxxxxxxx>
Reviewed-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
kernel/auditfilter.c | 13 -------------
1 file changed, 13 deletions(-)

--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -433,19 +433,6 @@ static struct audit_entry *audit_data_to
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;


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