From a5a6579db33af91f4f5134e14be758dc71c1b694 Mon Sep 17 00:00:00 2001
From: Jeff Vander Stoep <jeffv@google.com>
Date: Thu, 12 Mar 2015 16:26:17 -0700
Subject: [PATCH] mm: reorder can_do_mlock to fix audit denial
A userspace call to mmap(MAP_LOCKED) may result in the successful locking
of memory while also producing a confusing audit log denial. can_do_mlock
checks capable and rlimit. If either of these return positive
can_do_mlock returns true. The capable check leads to an LSM hook used by
apparmour and selinux which produce the audit denial. Reordering so
rlimit is checked first eliminates the denial on success, only recording a
denial when the lock is unsuccessful as a result of the denial.
Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
Acked-by: Nick Kralevich <nnk@google.com>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Paul Cassella <cassella@cray.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/mlock.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/mlock.c b/mm/mlock.c
index 73cf0987088c36..8a54cd21492587 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -26,10 +26,10 @@
int can_do_mlock(void)
{
- if (capable(CAP_IPC_LOCK))
- return 1;
if (rlimit(RLIMIT_MEMLOCK) != 0)
return 1;
+ if (capable(CAP_IPC_LOCK))
+ return 1;
return 0;
}
EXPORT_SYMBOL(can_do_mlock);
--
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