Commit ea5693cc authored Nov 28, 2008 by Patrick McHardy Committed by David S. Miller Nov 28, 2008

netlink: allow empty nested attributes



validate_nla() currently doesn't allow empty nested attributes. This
makes userspace code unnecessarily complicated when starting and ending
the nested attribute is done by generic upper level code and the inner
attributes are dumped by a module.

Add a special case to accept empty nested attributes. When the nested
attribute is non empty, the same checks as before are performed.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent ed77a89c

net/netlink/attr.c

+6 −0

Original line number	Original line	Diff line number	Diff line
	@@ -83,6 +83,12 @@ static int validate_nla(struct nlattr *nla, int maxtype,
	if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla))		if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla))
	return -ERANGE;		return -ERANGE;
	break;		break;
			case NLA_NESTED:
			/* a nested attributes is allowed to be empty; if its not,
			* it must have a size of at least NLA_HDRLEN.
			*/
			if (attrlen == 0)
			break;
	default:		default:
	if (pt->len)		if (pt->len)
	minlen = pt->len;		minlen = pt->len;