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![Jakub Kicinski](/assets/img/avatar_default.png)
We had historically not checked that genlmsghdr.reserved is 0 on input which prevents us from using those precious bytes in the future. One use case would be to extend the cmd field, which is currently just 8 bits wide and 256 is not a lot of commands for some core families. To make sure that new families do the right thing by default put the onus of opting out of validation on existing families. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> (NetLabel) Signed-off-by: David S. Miller <davem@davemloft.net>
512 lines
13 KiB
C
512 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* net/psample/psample.c - Netlink channel for packet sampling
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* Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include <linux/module.h>
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#include <linux/timekeeping.h>
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#include <net/net_namespace.h>
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#include <net/sock.h>
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#include <net/netlink.h>
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#include <net/genetlink.h>
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#include <net/psample.h>
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#include <linux/spinlock.h>
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#include <net/ip_tunnels.h>
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#include <net/dst_metadata.h>
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#define PSAMPLE_MAX_PACKET_SIZE 0xffff
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static LIST_HEAD(psample_groups_list);
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static DEFINE_SPINLOCK(psample_groups_lock);
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/* multicast groups */
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enum psample_nl_multicast_groups {
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PSAMPLE_NL_MCGRP_CONFIG,
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PSAMPLE_NL_MCGRP_SAMPLE,
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};
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static const struct genl_multicast_group psample_nl_mcgrps[] = {
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[PSAMPLE_NL_MCGRP_CONFIG] = { .name = PSAMPLE_NL_MCGRP_CONFIG_NAME },
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[PSAMPLE_NL_MCGRP_SAMPLE] = { .name = PSAMPLE_NL_MCGRP_SAMPLE_NAME },
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};
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static struct genl_family psample_nl_family __ro_after_init;
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static int psample_group_nl_fill(struct sk_buff *msg,
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struct psample_group *group,
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enum psample_command cmd, u32 portid, u32 seq,
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int flags)
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{
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void *hdr;
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int ret;
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hdr = genlmsg_put(msg, portid, seq, &psample_nl_family, flags, cmd);
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if (!hdr)
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return -EMSGSIZE;
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ret = nla_put_u32(msg, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
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if (ret < 0)
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goto error;
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ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_REFCOUNT, group->refcount);
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if (ret < 0)
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goto error;
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ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_SEQ, group->seq);
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if (ret < 0)
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goto error;
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genlmsg_end(msg, hdr);
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return 0;
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error:
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genlmsg_cancel(msg, hdr);
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return -EMSGSIZE;
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}
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static int psample_nl_cmd_get_group_dumpit(struct sk_buff *msg,
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struct netlink_callback *cb)
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{
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struct psample_group *group;
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int start = cb->args[0];
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int idx = 0;
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int err;
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spin_lock_bh(&psample_groups_lock);
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list_for_each_entry(group, &psample_groups_list, list) {
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if (!net_eq(group->net, sock_net(msg->sk)))
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continue;
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if (idx < start) {
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idx++;
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continue;
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}
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err = psample_group_nl_fill(msg, group, PSAMPLE_CMD_NEW_GROUP,
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NETLINK_CB(cb->skb).portid,
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cb->nlh->nlmsg_seq, NLM_F_MULTI);
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if (err)
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break;
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idx++;
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}
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spin_unlock_bh(&psample_groups_lock);
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cb->args[0] = idx;
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return msg->len;
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}
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static const struct genl_small_ops psample_nl_ops[] = {
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{
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.cmd = PSAMPLE_CMD_GET_GROUP,
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.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
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.dumpit = psample_nl_cmd_get_group_dumpit,
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/* can be retrieved by unprivileged users */
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}
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};
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static struct genl_family psample_nl_family __ro_after_init = {
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.name = PSAMPLE_GENL_NAME,
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.version = PSAMPLE_GENL_VERSION,
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.maxattr = PSAMPLE_ATTR_MAX,
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.netnsok = true,
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.module = THIS_MODULE,
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.mcgrps = psample_nl_mcgrps,
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.small_ops = psample_nl_ops,
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.n_small_ops = ARRAY_SIZE(psample_nl_ops),
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.resv_start_op = PSAMPLE_CMD_GET_GROUP + 1,
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.n_mcgrps = ARRAY_SIZE(psample_nl_mcgrps),
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};
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static void psample_group_notify(struct psample_group *group,
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enum psample_command cmd)
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{
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struct sk_buff *msg;
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int err;
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msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
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if (!msg)
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return;
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err = psample_group_nl_fill(msg, group, cmd, 0, 0, NLM_F_MULTI);
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if (!err)
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genlmsg_multicast_netns(&psample_nl_family, group->net, msg, 0,
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PSAMPLE_NL_MCGRP_CONFIG, GFP_ATOMIC);
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else
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nlmsg_free(msg);
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}
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static struct psample_group *psample_group_create(struct net *net,
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u32 group_num)
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{
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struct psample_group *group;
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group = kzalloc(sizeof(*group), GFP_ATOMIC);
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if (!group)
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return NULL;
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group->net = net;
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group->group_num = group_num;
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list_add_tail(&group->list, &psample_groups_list);
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psample_group_notify(group, PSAMPLE_CMD_NEW_GROUP);
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return group;
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}
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static void psample_group_destroy(struct psample_group *group)
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{
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psample_group_notify(group, PSAMPLE_CMD_DEL_GROUP);
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list_del(&group->list);
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kfree_rcu(group, rcu);
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}
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static struct psample_group *
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psample_group_lookup(struct net *net, u32 group_num)
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{
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struct psample_group *group;
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list_for_each_entry(group, &psample_groups_list, list)
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if ((group->group_num == group_num) && (group->net == net))
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return group;
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return NULL;
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}
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struct psample_group *psample_group_get(struct net *net, u32 group_num)
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{
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struct psample_group *group;
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spin_lock_bh(&psample_groups_lock);
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group = psample_group_lookup(net, group_num);
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if (!group) {
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group = psample_group_create(net, group_num);
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if (!group)
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goto out;
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}
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group->refcount++;
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out:
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spin_unlock_bh(&psample_groups_lock);
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return group;
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}
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EXPORT_SYMBOL_GPL(psample_group_get);
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void psample_group_take(struct psample_group *group)
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{
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spin_lock_bh(&psample_groups_lock);
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group->refcount++;
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spin_unlock_bh(&psample_groups_lock);
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}
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EXPORT_SYMBOL_GPL(psample_group_take);
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void psample_group_put(struct psample_group *group)
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{
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spin_lock_bh(&psample_groups_lock);
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if (--group->refcount == 0)
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psample_group_destroy(group);
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spin_unlock_bh(&psample_groups_lock);
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}
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EXPORT_SYMBOL_GPL(psample_group_put);
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#ifdef CONFIG_INET
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static int __psample_ip_tun_to_nlattr(struct sk_buff *skb,
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struct ip_tunnel_info *tun_info)
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{
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unsigned short tun_proto = ip_tunnel_info_af(tun_info);
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const void *tun_opts = ip_tunnel_info_opts(tun_info);
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const struct ip_tunnel_key *tun_key = &tun_info->key;
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int tun_opts_len = tun_info->options_len;
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if (tun_key->tun_flags & TUNNEL_KEY &&
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nla_put_be64(skb, PSAMPLE_TUNNEL_KEY_ATTR_ID, tun_key->tun_id,
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PSAMPLE_TUNNEL_KEY_ATTR_PAD))
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return -EMSGSIZE;
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if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE &&
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nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_INFO_BRIDGE))
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return -EMSGSIZE;
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switch (tun_proto) {
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case AF_INET:
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if (tun_key->u.ipv4.src &&
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nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_SRC,
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tun_key->u.ipv4.src))
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return -EMSGSIZE;
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if (tun_key->u.ipv4.dst &&
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nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_DST,
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tun_key->u.ipv4.dst))
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return -EMSGSIZE;
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break;
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case AF_INET6:
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if (!ipv6_addr_any(&tun_key->u.ipv6.src) &&
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nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_SRC,
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&tun_key->u.ipv6.src))
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return -EMSGSIZE;
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if (!ipv6_addr_any(&tun_key->u.ipv6.dst) &&
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nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_DST,
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&tun_key->u.ipv6.dst))
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return -EMSGSIZE;
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break;
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}
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if (tun_key->tos &&
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nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TOS, tun_key->tos))
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return -EMSGSIZE;
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if (nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TTL, tun_key->ttl))
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return -EMSGSIZE;
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if ((tun_key->tun_flags & TUNNEL_DONT_FRAGMENT) &&
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nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_DONT_FRAGMENT))
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return -EMSGSIZE;
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if ((tun_key->tun_flags & TUNNEL_CSUM) &&
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nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_CSUM))
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return -EMSGSIZE;
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if (tun_key->tp_src &&
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nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_SRC, tun_key->tp_src))
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return -EMSGSIZE;
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if (tun_key->tp_dst &&
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nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_DST, tun_key->tp_dst))
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return -EMSGSIZE;
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if ((tun_key->tun_flags & TUNNEL_OAM) &&
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nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_OAM))
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return -EMSGSIZE;
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if (tun_opts_len) {
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if (tun_key->tun_flags & TUNNEL_GENEVE_OPT &&
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nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_GENEVE_OPTS,
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tun_opts_len, tun_opts))
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return -EMSGSIZE;
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else if (tun_key->tun_flags & TUNNEL_ERSPAN_OPT &&
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nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_ERSPAN_OPTS,
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tun_opts_len, tun_opts))
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return -EMSGSIZE;
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}
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return 0;
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}
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static int psample_ip_tun_to_nlattr(struct sk_buff *skb,
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struct ip_tunnel_info *tun_info)
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{
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struct nlattr *nla;
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int err;
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nla = nla_nest_start_noflag(skb, PSAMPLE_ATTR_TUNNEL);
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if (!nla)
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return -EMSGSIZE;
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err = __psample_ip_tun_to_nlattr(skb, tun_info);
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if (err) {
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nla_nest_cancel(skb, nla);
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return err;
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}
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nla_nest_end(skb, nla);
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return 0;
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}
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static int psample_tunnel_meta_len(struct ip_tunnel_info *tun_info)
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{
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unsigned short tun_proto = ip_tunnel_info_af(tun_info);
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const struct ip_tunnel_key *tun_key = &tun_info->key;
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int tun_opts_len = tun_info->options_len;
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int sum = nla_total_size(0); /* PSAMPLE_ATTR_TUNNEL */
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if (tun_key->tun_flags & TUNNEL_KEY)
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sum += nla_total_size_64bit(sizeof(u64));
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if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE)
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sum += nla_total_size(0);
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switch (tun_proto) {
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case AF_INET:
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if (tun_key->u.ipv4.src)
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sum += nla_total_size(sizeof(u32));
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if (tun_key->u.ipv4.dst)
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sum += nla_total_size(sizeof(u32));
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break;
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case AF_INET6:
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if (!ipv6_addr_any(&tun_key->u.ipv6.src))
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sum += nla_total_size(sizeof(struct in6_addr));
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if (!ipv6_addr_any(&tun_key->u.ipv6.dst))
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sum += nla_total_size(sizeof(struct in6_addr));
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break;
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}
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if (tun_key->tos)
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sum += nla_total_size(sizeof(u8));
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sum += nla_total_size(sizeof(u8)); /* TTL */
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if (tun_key->tun_flags & TUNNEL_DONT_FRAGMENT)
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sum += nla_total_size(0);
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if (tun_key->tun_flags & TUNNEL_CSUM)
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sum += nla_total_size(0);
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if (tun_key->tp_src)
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sum += nla_total_size(sizeof(u16));
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if (tun_key->tp_dst)
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sum += nla_total_size(sizeof(u16));
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if (tun_key->tun_flags & TUNNEL_OAM)
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sum += nla_total_size(0);
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if (tun_opts_len) {
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if (tun_key->tun_flags & TUNNEL_GENEVE_OPT)
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sum += nla_total_size(tun_opts_len);
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else if (tun_key->tun_flags & TUNNEL_ERSPAN_OPT)
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sum += nla_total_size(tun_opts_len);
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}
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return sum;
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}
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#endif
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void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,
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u32 sample_rate, const struct psample_metadata *md)
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{
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ktime_t tstamp = ktime_get_real();
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int out_ifindex = md->out_ifindex;
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int in_ifindex = md->in_ifindex;
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u32 trunc_size = md->trunc_size;
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#ifdef CONFIG_INET
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struct ip_tunnel_info *tun_info;
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#endif
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struct sk_buff *nl_skb;
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int data_len;
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int meta_len;
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void *data;
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int ret;
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meta_len = (in_ifindex ? nla_total_size(sizeof(u16)) : 0) +
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(out_ifindex ? nla_total_size(sizeof(u16)) : 0) +
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(md->out_tc_valid ? nla_total_size(sizeof(u16)) : 0) +
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(md->out_tc_occ_valid ? nla_total_size_64bit(sizeof(u64)) : 0) +
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(md->latency_valid ? nla_total_size_64bit(sizeof(u64)) : 0) +
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nla_total_size(sizeof(u32)) + /* sample_rate */
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nla_total_size(sizeof(u32)) + /* orig_size */
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nla_total_size(sizeof(u32)) + /* group_num */
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nla_total_size(sizeof(u32)) + /* seq */
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nla_total_size_64bit(sizeof(u64)) + /* timestamp */
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nla_total_size(sizeof(u16)); /* protocol */
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#ifdef CONFIG_INET
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tun_info = skb_tunnel_info(skb);
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if (tun_info)
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meta_len += psample_tunnel_meta_len(tun_info);
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#endif
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data_len = min(skb->len, trunc_size);
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if (meta_len + nla_total_size(data_len) > PSAMPLE_MAX_PACKET_SIZE)
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data_len = PSAMPLE_MAX_PACKET_SIZE - meta_len - NLA_HDRLEN
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- NLA_ALIGNTO;
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nl_skb = genlmsg_new(meta_len + nla_total_size(data_len), GFP_ATOMIC);
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if (unlikely(!nl_skb))
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return;
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data = genlmsg_put(nl_skb, 0, 0, &psample_nl_family, 0,
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PSAMPLE_CMD_SAMPLE);
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if (unlikely(!data))
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goto error;
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if (in_ifindex) {
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ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_IIFINDEX, in_ifindex);
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if (unlikely(ret < 0))
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goto error;
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}
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if (out_ifindex) {
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ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OIFINDEX, out_ifindex);
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if (unlikely(ret < 0))
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goto error;
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}
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ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_RATE, sample_rate);
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if (unlikely(ret < 0))
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goto error;
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ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_ORIGSIZE, skb->len);
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if (unlikely(ret < 0))
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goto error;
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ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
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if (unlikely(ret < 0))
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goto error;
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ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_GROUP_SEQ, group->seq++);
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if (unlikely(ret < 0))
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goto error;
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if (md->out_tc_valid) {
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ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OUT_TC, md->out_tc);
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if (unlikely(ret < 0))
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goto error;
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}
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if (md->out_tc_occ_valid) {
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ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_OUT_TC_OCC,
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md->out_tc_occ, PSAMPLE_ATTR_PAD);
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if (unlikely(ret < 0))
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goto error;
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|
}
|
|
|
|
if (md->latency_valid) {
|
|
ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_LATENCY,
|
|
md->latency, PSAMPLE_ATTR_PAD);
|
|
if (unlikely(ret < 0))
|
|
goto error;
|
|
}
|
|
|
|
ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_TIMESTAMP,
|
|
ktime_to_ns(tstamp), PSAMPLE_ATTR_PAD);
|
|
if (unlikely(ret < 0))
|
|
goto error;
|
|
|
|
ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_PROTO,
|
|
be16_to_cpu(skb->protocol));
|
|
if (unlikely(ret < 0))
|
|
goto error;
|
|
|
|
if (data_len) {
|
|
int nla_len = nla_total_size(data_len);
|
|
struct nlattr *nla;
|
|
|
|
nla = skb_put(nl_skb, nla_len);
|
|
nla->nla_type = PSAMPLE_ATTR_DATA;
|
|
nla->nla_len = nla_attr_size(data_len);
|
|
|
|
if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
|
|
goto error;
|
|
}
|
|
|
|
#ifdef CONFIG_INET
|
|
if (tun_info) {
|
|
ret = psample_ip_tun_to_nlattr(nl_skb, tun_info);
|
|
if (unlikely(ret < 0))
|
|
goto error;
|
|
}
|
|
#endif
|
|
|
|
genlmsg_end(nl_skb, data);
|
|
genlmsg_multicast_netns(&psample_nl_family, group->net, nl_skb, 0,
|
|
PSAMPLE_NL_MCGRP_SAMPLE, GFP_ATOMIC);
|
|
|
|
return;
|
|
error:
|
|
pr_err_ratelimited("Could not create psample log message\n");
|
|
nlmsg_free(nl_skb);
|
|
}
|
|
EXPORT_SYMBOL_GPL(psample_sample_packet);
|
|
|
|
static int __init psample_module_init(void)
|
|
{
|
|
return genl_register_family(&psample_nl_family);
|
|
}
|
|
|
|
static void __exit psample_module_exit(void)
|
|
{
|
|
genl_unregister_family(&psample_nl_family);
|
|
}
|
|
|
|
module_init(psample_module_init);
|
|
module_exit(psample_module_exit);
|
|
|
|
MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
|
|
MODULE_DESCRIPTION("netlink channel for packet sampling");
|
|
MODULE_LICENSE("GPL v2");
|