On Fri, Oct 05, 2018 at 07:48:27PM +0200, Christian Brauner wrote:

On Thu, Oct 04, 2018 at 02:33:46PM -0700, David Ahern wrote:

quoted

From: David Ahern <redacted>

Update inet6_dump_ifinfo for strict data checking. If the flag is
set, the dump request is expected to have an ifinfomsg struct as
the header. All elements of the struct are expected to be 0 and no
attributes can be appended.

Signed-off-by: David Ahern <redacted>

This is on top of current net-next? Are your patches ensuring that
ipv6 addr requests don't generate log messages anymore when a wrong
header is passed but the strict socket option is not passed? The context
here doesn't seem to indicate that. :)

Nm, 9/10 takes care of that. Thanks! :)

quoted

---
 net/ipv6/addrconf.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index f749a3ad721a..693199a29426 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c

@@ -5628,6 +5628,31 @@ static int inet6_fill_ifinfo(struct sk_buff *skb, struct inet6_dev *idev,
 	return -EMSGSIZE;
 }
 
+static int inet6_valid_dump_ifinfo(const struct nlmsghdr *nlh,
+				   struct netlink_ext_ack *extack)
+{
+	struct ifinfomsg *ifm;
+
+	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifm))) {
+		NL_SET_ERR_MSG(extack, "Invalid header");
+		return -EINVAL;
+	}
+
+	if (nlh->nlmsg_len > nlmsg_msg_size(sizeof(*ifm))) {
+		NL_SET_ERR_MSG(extack, "Invalid data after header");
+		return -EINVAL;
+	}
+
+	ifm = nlmsg_data(nlh);
+	if (ifm->__ifi_pad || ifm->ifi_type || ifm->ifi_flags ||
+	    ifm->ifi_change || ifm->ifi_index) {
+		NL_SET_ERR_MSG(extack, "Invalid values in header for dump request");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int inet6_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	struct net *net = sock_net(skb->sk);

@@ -5637,6 +5662,16 @@ static int inet6_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 	struct inet6_dev *idev;
 	struct hlist_head *head;
 
+	/* only requests using strict checking can pass data to
+	 * influence the dump
+	 */
+	if (cb->strict_check) {
+		int err = inet6_valid_dump_ifinfo(cb->nlh, cb->extack);
+
+		if (err)
+			return err;
+	}
+
 	s_h = cb->args[0];
 	s_idx = cb->args[1];
 

-- 
2.11.0