selinux: convert the policy type_attr_map to flex_array

Current selinux policy can have over 3000 types.  The type_attr_map in
policy is an array sized by the number of types times sizeof(struct ebitmap)
(12 on x86_64).  Basic math tells us the array is going to be of length
3000 x 12 = 36,000 bytes.  The largest 'safe' allocation on a long running
system is 16k.  Most of the time a 32k allocation will work.  But on long
running systems a 64k allocation (what we need) can fail quite regularly.
In order to deal with this I am converting the type_attr_map to use
flex_arrays.  Let the library code deal with breaking this into PAGE_SIZE
pieces.

-v2
rework some of the if(!obj) BUG() to be BUG_ON(!obj)
drop flex_array_put() calls and just use a _get() object directly

-v3
make apply to James' tree (drop the policydb_write changes)

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by:  Stephen D. Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h
index 26d9adf8542..310e94442cb 100644
--- a/security/selinux/ss/policydb.h
+++ b/security/selinux/ss/policydb.h
@@ -24,6 +24,8 @@
 #ifndef _SS_POLICYDB_H_
 #define _SS_POLICYDB_H_
 
+#include <linux/flex_array.h>
+
 #include "symtab.h"
 #include "avtab.h"
 #include "sidtab.h"
@@ -246,7 +248,7 @@ struct policydb {
 	struct hashtab *range_tr;
 
 	/* type -> attribute reverse mapping */
-	struct ebitmap *type_attr_map;
+	struct flex_array *type_attr_map_array;
 
 	struct ebitmap policycaps;