Audit: use new LSM hooks instead of SELinux exports

Stop using the following exported SELinux interfaces:
selinux_get_inode_sid(inode, sid)
selinux_get_ipc_sid(ipcp, sid)
selinux_get_task_sid(tsk, sid)
selinux_sid_to_string(sid, ctx, len)
kfree(ctx)

and use following generic LSM equivalents respectively:
security_inode_getsecid(inode, secid)
security_ipc_getsecid*(ipcp, secid)
security_task_getsecid(tsk, secid)
security_sid_to_secctx(sid, ctx, len)
security_release_secctx(ctx, len)

Call security_release_secctx only if security_secid_to_secctx
succeeded.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Ahmed S. Darwish <darwish.07@gmail.com>
Acked-by: James Morris <jmorris@namei.org>
Reviewed-by: Paul Moore <paul.moore@hp.com>
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 2f2914b..35e58a1 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -28,6 +28,7 @@
 #include <linux/netlink.h>
 #include <linux/sched.h>
 #include <linux/inotify.h>
+#include <linux/security.h>
 #include <linux/selinux.h>
 #include "audit.h"
 
@@ -1515,11 +1516,12 @@
 	if (sid) {
 		char *ctx = NULL;
 		u32 len;
-		if (selinux_sid_to_string(sid, &ctx, &len))
+		if (security_secid_to_secctx(sid, &ctx, &len))
 			audit_log_format(ab, " ssid=%u", sid);
-		else
+		else {
 			audit_log_format(ab, " subj=%s", ctx);
-		kfree(ctx);
+			security_release_secctx(ctx, len);
+		}
 	}
 	audit_log_format(ab, " op=%s rule key=", action);
 	if (rule->filterkey)