From: Zhen Lei <thunder.leizhen@huawei.com>
Date: Thu, 22 Aug 2024 14:08:58 +0000 (+0800)
Subject: selinux: simplify avc_xperms_audit_required()
X-Git-Tag: v6.12-rc1~199^2~1
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=68cfb28332420e0515cb6ffdb46921d59ba9739f;p=thirdparty%2Flinux.git

selinux: simplify avc_xperms_audit_required()

By associative and commutative laws, the result of the two 'audited' is
zero. Take the second 'audited' as an example:
  1) audited = requested & avd->auditallow;
  2) audited &= ~requested;
  ==> audited = ~requested & (requested & avd->auditallow);
  ==> audited = (~requested & requested) & avd->auditallow;
  ==> audited = 0 & avd->auditallow;
  ==> audited = 0;

In fact, it is more readable to directly write zero. The value of the
first 'audited' is 0 because AUDIT is not allowed. The second 'audited'
is zero because there is no AUDITALLOW permission.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
---

diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index 1ec377ce6d226..e0d1a9dfaceea 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -388,7 +388,7 @@ static inline u32 avc_xperms_audit_required(u32 requested,
 		audited = denied & avd->auditdeny;
 		if (audited && xpd) {
 			if (avc_xperms_has_perm(xpd, perm, XPERMS_DONTAUDIT))
-				audited &= ~requested;
+				audited = 0;
 		}
 	} else if (result) {
 		audited = denied = requested;
@@ -396,7 +396,7 @@ static inline u32 avc_xperms_audit_required(u32 requested,
 		audited = requested & avd->auditallow;
 		if (audited && xpd) {
 			if (!avc_xperms_has_perm(xpd, perm, XPERMS_AUDITALLOW))
-				audited &= ~requested;
+				audited = 0;
 		}
 	}