LSM: shrink sizeof LSM specific portion of common_audit_data

Linus found that the gigantic size of the common audit data caused a big
perf hit on something as simple as running stat() in a loop.  This patch
requires LSMs to declare the LSM specific portion separately rather than
doing it in a union.  Thus each LSM can be responsible for shrinking their
portion and don't have to pay a penalty just because other LSMs have a
bigger space requirement.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/security/apparmor/ipc.c b/security/apparmor/ipc.c
index 7ee05c6f3c6..c3da93a5150 100644
--- a/security/apparmor/ipc.c
+++ b/security/apparmor/ipc.c
@@ -26,7 +26,7 @@ static void audit_cb(struct audit_buffer *ab, void *va)
 {
 	struct common_audit_data *sa = va;
 	audit_log_format(ab, " target=");
-	audit_log_untrustedstring(ab, sa->aad.target);
+	audit_log_untrustedstring(ab, sa->aad->target);
 }
 
 /**
@@ -41,10 +41,12 @@ static int aa_audit_ptrace(struct aa_profile *profile,
 			   struct aa_profile *target, int error)
 {
 	struct common_audit_data sa;
+	struct apparmor_audit_data aad = {0,};
 	COMMON_AUDIT_DATA_INIT(&sa, NONE);
-	sa.aad.op = OP_PTRACE;
-	sa.aad.target = target;
-	sa.aad.error = error;
+	sa.aad = &aad;
+	aad.op = OP_PTRACE;
+	aad.target = target;
+	aad.error = error;
 
 	return aa_audit(AUDIT_APPARMOR_AUTO, profile, GFP_ATOMIC, &sa,
 			audit_cb);