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authorDavid Ahern <dsahern@gmail.com>2018-10-07 20:16:31 -0700
committerDavid S. Miller <davem@davemloft.net>2018-10-08 10:39:04 -0700
commit2d011be8c07b50e8b3699d06ee11af5f5914b09a (patch)
tree6c3d44a3e11fd4038f9c8d0a1e09cf6748cae801
parent905cf0abe8c2c892313f08e38d808eee4e794987 (diff)
downloadlinux-2d011be8c07b50e8b3699d06ee11af5f5914b09a.tar.bz2
rtnetlink: Update rtnl_bridge_getlink for strict data checking
Update rtnl_bridge_getlink for strict data checking. If the flag is set, the dump request is expected to have an ifinfomsg 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 supported by the dump handler are allowed to be non-0 or set in the request. At the moment only the IFLA_EXT_MASK attribute is supported. Signed-off-by: David Ahern <dsahern@gmail.com> Acked-by: Christian Brauner <christian@brauner.io> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/core/rtnetlink.c70
1 files changed, 57 insertions, 13 deletions
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 12fd52105005..e38e1f178611 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -4021,28 +4021,72 @@ nla_put_failure:
}
EXPORT_SYMBOL_GPL(ndo_dflt_bridge_getlink);
+static int valid_bridge_getlink_req(const struct nlmsghdr *nlh,
+ bool strict_check, u32 *filter_mask,
+ struct netlink_ext_ack *extack)
+{
+ struct nlattr *tb[IFLA_MAX+1];
+ int err, i;
+
+ if (strict_check) {
+ struct ifinfomsg *ifm;
+
+ if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifm))) {
+ NL_SET_ERR_MSG(extack, "Invalid header for bridge link dump");
+ 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 bridge link dump request");
+ return -EINVAL;
+ }
+
+ err = nlmsg_parse_strict(nlh, sizeof(struct ifinfomsg), tb,
+ IFLA_MAX, ifla_policy, extack);
+ } else {
+ err = nlmsg_parse(nlh, sizeof(struct ifinfomsg), tb,
+ IFLA_MAX, ifla_policy, extack);
+ }
+ if (err < 0)
+ return err;
+
+ /* new attributes should only be added with strict checking */
+ for (i = 0; i <= IFLA_MAX; ++i) {
+ if (!tb[i])
+ continue;
+
+ switch (i) {
+ case IFLA_EXT_MASK:
+ *filter_mask = nla_get_u32(tb[i]);
+ break;
+ default:
+ if (strict_check) {
+ NL_SET_ERR_MSG(extack, "Unsupported attribute in bridge link dump request");
+ return -EINVAL;
+ }
+ }
+ }
+
+ return 0;
+}
+
static int rtnl_bridge_getlink(struct sk_buff *skb, struct netlink_callback *cb)
{
+ const struct nlmsghdr *nlh = cb->nlh;
struct net *net = sock_net(skb->sk);
struct net_device *dev;
int idx = 0;
u32 portid = NETLINK_CB(cb->skb).portid;
- u32 seq = cb->nlh->nlmsg_seq;
+ u32 seq = nlh->nlmsg_seq;
u32 filter_mask = 0;
int err;
- if (nlmsg_len(cb->nlh) > sizeof(struct ifinfomsg)) {
- struct nlattr *extfilt;
-
- extfilt = nlmsg_find_attr(cb->nlh, sizeof(struct ifinfomsg),
- IFLA_EXT_MASK);
- if (extfilt) {
- if (nla_len(extfilt) < sizeof(filter_mask))
- return -EINVAL;
-
- filter_mask = nla_get_u32(extfilt);
- }
- }
+ err = valid_bridge_getlink_req(nlh, cb->strict_check, &filter_mask,
+ cb->extack);
+ if (err < 0 && cb->strict_check)
+ return err;
rcu_read_lock();
for_each_netdev_rcu(net, dev) {