On Fri, Sep 28, 2018 at 08:45:01AM -0700, dsah...@kernel.org wrote:
> From: David Ahern <dsah...@gmail.com>
>
> Update inet_dump_ifaddr to check for NLM_F_DUMP_PROPER_HDR in the netlink
> message header. If the flag is set, the dump request is expected to have
> an ifaddrmsg struct as the header potentially followed by one or more
> attributes. Any data passed in the header or as an attribute is taken as
> a request to influence the data returned. Only values suppored by the
> dump handler are allowed to be non-0 or set in the request. At the moment
> only the IFA_TARGET_NETNSID attribute is supported. Follow on patches
> will support for other fields (e.g., honor ifa_index and only return data
> for the given device index).
>
> Signed-off-by: David Ahern <dsah...@gmail.com>
> ---
> net/ipv4/devinet.c | 52 +++++++++++++++++++++++++++++++++++++++++-----------
> 1 file changed, 41 insertions(+), 11 deletions(-)
>
> diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
> index 44d931a3cd50..1e06a21cd8f4 100644
> --- a/net/ipv4/devinet.c
> +++ b/net/ipv4/devinet.c
> @@ -1661,15 +1661,15 @@ static int inet_fill_ifaddr(struct sk_buff *skb,
> struct in_ifaddr *ifa,
>
> static int inet_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
> {
> + struct netlink_ext_ack *extack = cb->extack;
> + const struct nlmsghdr *nlh = cb->nlh;
> struct inet_fill_args fillargs = {
> .portid = NETLINK_CB(cb->skb).portid,
> - .seq = cb->nlh->nlmsg_seq,
> + .seq = nlh->nlmsg_seq,
> .event = RTM_NEWADDR,
> - .flags = NLM_F_MULTI,
> .netnsid = -1,
> };
> struct net *net = sock_net(skb->sk);
> - struct nlattr *tb[IFA_MAX+1];
> struct net *tgt_net = net;
> int h, s_h;
> int idx, s_idx;
> @@ -1683,15 +1683,45 @@ static int inet_dump_ifaddr(struct sk_buff *skb,
> struct netlink_callback *cb)
> s_idx = idx = cb->args[1];
> s_ip_idx = ip_idx = cb->args[2];
>
> - if (nlmsg_parse(cb->nlh, sizeof(struct ifaddrmsg), tb, IFA_MAX,
> - ifa_ipv4_policy, NULL) >= 0) {
> - if (tb[IFA_TARGET_NETNSID]) {
> - fillargs.netnsid = nla_get_s32(tb[IFA_TARGET_NETNSID]);
> + if (nlh->nlmsg_flags & NLM_F_DUMP_PROPER_HDR) {
> + struct nlattr *tb[IFA_MAX+1];
> + struct ifaddrmsg *ifm;
> + int err, i;
> +
> + if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifm))) {
> + NL_SET_ERR_MSG(extack, "Invalid header");
> + return -EINVAL;
> + }
> +
> + ifm = (struct ifaddrmsg *) nlmsg_data(cb->nlh);
> + if (ifm->ifa_prefixlen || ifm->ifa_flags || ifm->ifa_scope) {
> + NL_SET_ERR_MSG(extack, "Invalid values in header for
> dump request");
> + return -EINVAL;
> + }
> + if (ifm->ifa_index) {
> + NL_SET_ERR_MSG(extack, "Filter by device index not
> supported");
> + return -EINVAL;
> + }
> + err = nlmsg_parse(cb->nlh, sizeof(struct ifaddrmsg), tb,
> IFA_MAX,
> + ifa_ipv4_policy, NULL);
> + if (err < 0)
> + return err;
>
> - tgt_net = rtnl_get_net_ns_capable(skb->sk,
> - fillargs.netnsid);
> - if (IS_ERR(tgt_net))
> - return PTR_ERR(tgt_net);
> + for (i = 0; i < IFA_MAX; ++i) {
> + if (i == IFA_TARGET_NETNSID) {
> + fillargs.netnsid = nla_get_s32(tb[i]);
> +
> + tgt_net = rtnl_get_net_ns_capable(skb->sk,
> +
> fillargs.netnsid);
> + if (IS_ERR(tgt_net))
> + return PTR_ERR(tgt_net);
> +
> + fillargs.flags |= NLM_F_DUMP_FILTERED;
> + }
> + if (tb[i]) {
> + NL_SET_ERR_MSG(extack, "Unsupported attribute
> in dump request");
> + return -EINVAL;
> + }
That loop doesn't do what it promises, no? Shouldn't it be:
for (i = 0; i < IFA_MAX; ++i) {
if (i == IFA_TARGET_NETNSID && tb[IFA_TARGET_NETNSID]) {
fillargs.netnsid = nla_get_s32(tb[i]);
tgt_net = rtnl_get_net_ns_capable(skb->sk,
fillargs.netnsid);
if (IS_ERR(tgt_net))
return PTR_ERR(tgt_net);
fillargs.flags |= NLM_F_DUMP_FILTERED;
continue;
}
if (tb[i]) {
NL_SET_ERR_MSG(extack, "Unsupported attribute
in dump request");
return -EINVAL;
}
}
> }
>
> --
> 2.11.0
>
