ima: Use kmemdup rather than kmalloc+memcpy

Issue identified with Coccinelle.
Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

security/integrity/ima/ima_policy.c

@@ -353,15 +353,14 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
 	struct ima_rule_entry *nentry;
 	int i;
 
-	nentry = kmalloc(sizeof(*nentry), GFP_KERNEL);
-	if (!nentry)
-		return NULL;
-
 	/*
 	 * Immutable elements are copied over as pointers and data; only
 	 * lsm rules can change
 	 */
-	memcpy(nentry, entry, sizeof(*nentry));
+	nentry = kmemdup(entry, sizeof(*nentry), GFP_KERNEL);
+	if (!nentry)
+		return NULL;
+
 	memset(nentry->lsm, 0, sizeof_field(struct ima_rule_entry, lsm));
 
 	for (i = 0; i < MAX_LSM_RULES; i++) {