apparmor: Use struct_size() helper in kzalloc()

Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows that,
in the worse scenario, could lead to heap overflows.

Link: https://github.com/KSPP/linux/issues/160
Signed-off-by: Gustavo A. R. Silva <[e-mail]>
Signed-off-by: John Johansen <[e-mail]>

security/apparmor/label.c

···
 	AA_BUG(size < 1);
 
 	/*  + 1 for null terminator entry on vec */
-	new = kzalloc(sizeof(*new) + sizeof(struct aa_profile *) * (size + 1),
-			gfp);
+	new = kzalloc(struct_size(new, vec, size + 1), gfp);
 	AA_DEBUG("%s (%p)\n", __func__, new);
 	if (!new)
 		goto fail;

security/apparmor/policy.c

···
 	struct aa_profile *profile;
 
 	/* freed by free_profile - usually through aa_put_profile */
-	profile = kzalloc(sizeof(*profile) + sizeof(struct aa_profile *) * 2,
-			  gfp);
+	profile = kzalloc(struct_size(profile, label.vec, 2), gfp);
 	if (!profile)
 		return NULL;