From: David Ahern <dsah...@gmail.com> Update br_mdb_dump 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 a br_port_msg 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 <dsah...@gmail.com> --- net/bridge/br_mdb.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/net/bridge/br_mdb.c b/net/bridge/br_mdb.c index a4a848bf827b..57c43c1b1e71 100644 --- a/net/bridge/br_mdb.c +++ b/net/bridge/br_mdb.c @@ -167,8 +167,26 @@ static int br_mdb_dump(struct sk_buff *skb, struct netlink_callback *cb) struct net_device *dev; struct net *net = sock_net(skb->sk); struct nlmsghdr *nlh = NULL; + struct br_port_msg *bpm; int idx = 0, s_idx; + if (cb->nlh->nlmsg_flags & NLM_F_DUMP_PROPER_HDR) { + struct netlink_ext_ack *extack = cb->extack; + + if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*bpm))) { + NL_SET_ERR_MSG(extack, "Invalid header"); + return -EINVAL; + } + if (bpm->ifindex) { + NL_SET_ERR_MSG(extack, "Filtering by device index is not supported"); + return -EINVAL; + } + if (nlh->nlmsg_len != nlmsg_msg_size(sizeof(*bpm))) { + NL_SET_ERR_MSG(extack, "Invalid data after header"); + return -EINVAL; + } + } + s_idx = cb->args[0]; rcu_read_lock(); @@ -178,8 +196,6 @@ static int br_mdb_dump(struct sk_buff *skb, struct netlink_callback *cb) for_each_netdev_rcu(net, dev) { if (dev->priv_flags & IFF_EBRIDGE) { - struct br_port_msg *bpm; - if (idx < s_idx) goto skip; -- 2.11.0