From: Christian Göttsche <cgzones@googlemail.com>
Date: Mon, 7 Aug 2023 17:11:38 +0000 (+0200)
Subject: selinux: make left shifts well defined
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=aa4b60518280834529f75cb7667ffac91967abea;p=linux.git

selinux: make left shifts well defined

The loops upper bound represent the number of permissions used (for the
current class or in general).  The limit for this is 32, thus we might
left shift of one less, 31.  Shifting a base of 1 results in undefined
behavior; use (u32)1 as base.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
---

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index dacec2ebdcd7d..1eeffc66ea7d7 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -207,22 +207,22 @@ static void map_decision(struct selinux_map *map,
 
 		for (i = 0, result = 0; i < n; i++) {
 			if (avd->allowed & mapping->perms[i])
-				result |= 1<<i;
+				result |= (u32)1<<i;
 			if (allow_unknown && !mapping->perms[i])
-				result |= 1<<i;
+				result |= (u32)1<<i;
 		}
 		avd->allowed = result;
 
 		for (i = 0, result = 0; i < n; i++)
 			if (avd->auditallow & mapping->perms[i])
-				result |= 1<<i;
+				result |= (u32)1<<i;
 		avd->auditallow = result;
 
 		for (i = 0, result = 0; i < n; i++) {
 			if (avd->auditdeny & mapping->perms[i])
-				result |= 1<<i;
+				result |= (u32)1<<i;
 			if (!allow_unknown && !mapping->perms[i])
-				result |= 1<<i;
+				result |= (u32)1<<i;
 		}
 		/*
 		 * In case the kernel has a bug and requests a permission
@@ -230,7 +230,7 @@ static void map_decision(struct selinux_map *map,
 		 * should audit that denial
 		 */
 		for (; i < (sizeof(u32)*8); i++)
-			result |= 1<<i;
+			result |= (u32)1<<i;
 		avd->auditdeny = result;
 	}
 }