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>

Author: cgzones

security/selinux/ss/services.c

@@ -207,30 +207,30 @@ 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
 		 * between num_perms and the maximum permission number, we
 		 * should audit that denial
 		 */
 		for (; i < (sizeof(u32)*8); i++)
-			result |= 1<<i;
+			result |= (u32)1<<i;
 		avd->auditdeny = result;
 	}
 }