From ed6eff11790a5bf1ce9b0421667e46ab1cf368f4 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Sun, 7 Oct 2018 20:16:29 -0700 Subject: [PATCH] net/ipv6: Update inet6_dump_addr for strict data checking Update inet6_dump_addr for strict data checking. 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 can add support for other fields (e.g., honor ifa_index and only return data for the given device index). Signed-off-by: David Ahern Acked-by: Christian Brauner Signed-off-by: David S. Miller --- net/ipv6/addrconf.c | 69 ++++++++++++++++++++++++++++++++++++++------- 1 file changed, 59 insertions(+), 10 deletions(-) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index afa279170ba5..095d3f56f0a9 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -4998,9 +4998,62 @@ static int in6_dump_addrs(struct inet6_dev *idev, struct sk_buff *skb, return err; } +static int inet6_valid_dump_ifaddr_req(const struct nlmsghdr *nlh, + struct inet6_fill_args *fillargs, + struct net **tgt_net, struct sock *sk, + struct netlink_ext_ack *extack) +{ + 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_MOD(extack, "Invalid header for address dump request"); + return -EINVAL; + } + + ifm = nlmsg_data(nlh); + if (ifm->ifa_prefixlen || ifm->ifa_flags || ifm->ifa_scope) { + NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for address dump request"); + return -EINVAL; + } + if (ifm->ifa_index) { + NL_SET_ERR_MSG_MOD(extack, "Filter by device index not supported for address dump"); + return -EINVAL; + } + + err = nlmsg_parse_strict(nlh, sizeof(*ifm), tb, IFA_MAX, + ifa_ipv6_policy, extack); + if (err < 0) + return err; + + for (i = 0; i <= IFA_MAX; ++i) { + if (!tb[i]) + continue; + + if (i == IFA_TARGET_NETNSID) { + struct net *net; + + fillargs->netnsid = nla_get_s32(tb[i]); + net = rtnl_get_net_ns_capable(sk, fillargs->netnsid); + if (IS_ERR(net)) { + NL_SET_ERR_MSG_MOD(extack, "Invalid target network namespace id"); + return PTR_ERR(net); + } + *tgt_net = net; + } else { + NL_SET_ERR_MSG_MOD(extack, "Unsupported attribute in dump request"); + return -EINVAL; + } + } + + return 0; +} + static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb, enum addr_type_t type) { + const struct nlmsghdr *nlh = cb->nlh; struct inet6_fill_args fillargs = { .portid = NETLINK_CB(cb->skb).portid, .seq = cb->nlh->nlmsg_seq, @@ -5009,7 +5062,6 @@ static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb, .type = type, }; struct net *net = sock_net(skb->sk); - struct nlattr *tb[IFA_MAX+1]; struct net *tgt_net = net; int h, s_h; int idx, ip_idx; @@ -5022,16 +5074,13 @@ static int inet6_dump_addr(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_ipv6_policy, cb->extack) >= 0) { - if (tb[IFA_TARGET_NETNSID]) { - fillargs.netnsid = nla_get_s32(tb[IFA_TARGET_NETNSID]); + if (cb->strict_check) { + int err; - tgt_net = rtnl_get_net_ns_capable(skb->sk, - fillargs.netnsid); - if (IS_ERR(tgt_net)) - return PTR_ERR(tgt_net); - } + err = inet6_valid_dump_ifaddr_req(nlh, &fillargs, &tgt_net, + skb->sk, cb->extack); + if (err < 0) + return err; } rcu_read_lock(); -- 2.30.2