![Dmytro Linkin](/assets/img/avatar_default.png)
Currently init call of all actions (except ipt) init their 'parm'
structure as a direct pointer to nla data in skb. This leads to race
condition when some of the filter actions were initialized successfully
(and were assigned with idr action index that was written directly
into nla data), but then were deleted and retried (due to following
action module missing or classifier-initiated retry), in which case
action init code tries to insert action to idr with index that was
assigned on previous iteration. During retry the index can be reused
by another action that was inserted concurrently, which causes
unintended action sharing between filters.
To fix described race condition, save action idr index to temporary
stack-allocated variable instead on nla data.
Fixes: 0190c1d452
("net: sched: atomically check-allocate action")
Signed-off-by: Dmytro Linkin <dmitrolin@mellanox.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
401 lines
10 KiB
C
401 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* net/sched/act_police.c Input police filter
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*
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* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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* J Hadi Salim (action changes)
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/skbuff.h>
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#include <linux/rtnetlink.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <net/act_api.h>
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#include <net/netlink.h>
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#include <net/pkt_cls.h>
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#include <net/tc_act/tc_police.h>
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/* Each policer is serialized by its individual spinlock */
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static unsigned int police_net_id;
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static struct tc_action_ops act_police_ops;
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static int tcf_police_walker(struct net *net, struct sk_buff *skb,
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struct netlink_callback *cb, int type,
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const struct tc_action_ops *ops,
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struct netlink_ext_ack *extack)
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{
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struct tc_action_net *tn = net_generic(net, police_net_id);
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return tcf_generic_walker(tn, skb, cb, type, ops, extack);
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}
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static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = {
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[TCA_POLICE_RATE] = { .len = TC_RTAB_SIZE },
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[TCA_POLICE_PEAKRATE] = { .len = TC_RTAB_SIZE },
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[TCA_POLICE_AVRATE] = { .type = NLA_U32 },
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[TCA_POLICE_RESULT] = { .type = NLA_U32 },
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};
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static int tcf_police_init(struct net *net, struct nlattr *nla,
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struct nlattr *est, struct tc_action **a,
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int ovr, int bind, bool rtnl_held,
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struct tcf_proto *tp,
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struct netlink_ext_ack *extack)
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{
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int ret = 0, tcfp_result = TC_ACT_OK, err, size;
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struct nlattr *tb[TCA_POLICE_MAX + 1];
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struct tcf_chain *goto_ch = NULL;
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struct tc_police *parm;
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struct tcf_police *police;
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struct qdisc_rate_table *R_tab = NULL, *P_tab = NULL;
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struct tc_action_net *tn = net_generic(net, police_net_id);
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struct tcf_police_params *new;
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bool exists = false;
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u32 index;
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if (nla == NULL)
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return -EINVAL;
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err = nla_parse_nested_deprecated(tb, TCA_POLICE_MAX, nla,
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police_policy, NULL);
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if (err < 0)
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return err;
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if (tb[TCA_POLICE_TBF] == NULL)
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return -EINVAL;
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size = nla_len(tb[TCA_POLICE_TBF]);
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if (size != sizeof(*parm) && size != sizeof(struct tc_police_compat))
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return -EINVAL;
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parm = nla_data(tb[TCA_POLICE_TBF]);
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index = parm->index;
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err = tcf_idr_check_alloc(tn, &index, a, bind);
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if (err < 0)
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return err;
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exists = err;
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if (exists && bind)
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return 0;
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if (!exists) {
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ret = tcf_idr_create(tn, index, NULL, a,
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&act_police_ops, bind, true);
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if (ret) {
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tcf_idr_cleanup(tn, index);
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return ret;
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}
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ret = ACT_P_CREATED;
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spin_lock_init(&(to_police(*a)->tcfp_lock));
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} else if (!ovr) {
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tcf_idr_release(*a, bind);
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return -EEXIST;
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}
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err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
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if (err < 0)
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goto release_idr;
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police = to_police(*a);
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if (parm->rate.rate) {
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err = -ENOMEM;
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R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE], NULL);
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if (R_tab == NULL)
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goto failure;
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if (parm->peakrate.rate) {
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P_tab = qdisc_get_rtab(&parm->peakrate,
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tb[TCA_POLICE_PEAKRATE], NULL);
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if (P_tab == NULL)
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goto failure;
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}
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}
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if (est) {
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err = gen_replace_estimator(&police->tcf_bstats,
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police->common.cpu_bstats,
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&police->tcf_rate_est,
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&police->tcf_lock,
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NULL, est);
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if (err)
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goto failure;
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} else if (tb[TCA_POLICE_AVRATE] &&
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(ret == ACT_P_CREATED ||
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!gen_estimator_active(&police->tcf_rate_est))) {
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err = -EINVAL;
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goto failure;
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}
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if (tb[TCA_POLICE_RESULT]) {
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tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
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if (TC_ACT_EXT_CMP(tcfp_result, TC_ACT_GOTO_CHAIN)) {
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NL_SET_ERR_MSG(extack,
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"goto chain not allowed on fallback");
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err = -EINVAL;
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goto failure;
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}
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}
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new = kzalloc(sizeof(*new), GFP_KERNEL);
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if (unlikely(!new)) {
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err = -ENOMEM;
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goto failure;
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}
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/* No failure allowed after this point */
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new->tcfp_result = tcfp_result;
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new->tcfp_mtu = parm->mtu;
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if (!new->tcfp_mtu) {
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new->tcfp_mtu = ~0;
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if (R_tab)
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new->tcfp_mtu = 255 << R_tab->rate.cell_log;
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}
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if (R_tab) {
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new->rate_present = true;
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psched_ratecfg_precompute(&new->rate, &R_tab->rate, 0);
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qdisc_put_rtab(R_tab);
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} else {
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new->rate_present = false;
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}
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if (P_tab) {
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new->peak_present = true;
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psched_ratecfg_precompute(&new->peak, &P_tab->rate, 0);
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qdisc_put_rtab(P_tab);
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} else {
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new->peak_present = false;
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}
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new->tcfp_burst = PSCHED_TICKS2NS(parm->burst);
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if (new->peak_present)
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new->tcfp_mtu_ptoks = (s64)psched_l2t_ns(&new->peak,
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new->tcfp_mtu);
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if (tb[TCA_POLICE_AVRATE])
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new->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]);
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spin_lock_bh(&police->tcf_lock);
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spin_lock_bh(&police->tcfp_lock);
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police->tcfp_t_c = ktime_get_ns();
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police->tcfp_toks = new->tcfp_burst;
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if (new->peak_present)
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police->tcfp_ptoks = new->tcfp_mtu_ptoks;
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spin_unlock_bh(&police->tcfp_lock);
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goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
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rcu_swap_protected(police->params,
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new,
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lockdep_is_held(&police->tcf_lock));
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spin_unlock_bh(&police->tcf_lock);
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if (goto_ch)
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tcf_chain_put_by_act(goto_ch);
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if (new)
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kfree_rcu(new, rcu);
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if (ret == ACT_P_CREATED)
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tcf_idr_insert(tn, *a);
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return ret;
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failure:
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qdisc_put_rtab(P_tab);
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qdisc_put_rtab(R_tab);
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if (goto_ch)
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tcf_chain_put_by_act(goto_ch);
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release_idr:
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tcf_idr_release(*a, bind);
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return err;
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}
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static int tcf_police_act(struct sk_buff *skb, const struct tc_action *a,
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struct tcf_result *res)
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{
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struct tcf_police *police = to_police(a);
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struct tcf_police_params *p;
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s64 now, toks, ptoks = 0;
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int ret;
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tcf_lastuse_update(&police->tcf_tm);
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bstats_cpu_update(this_cpu_ptr(police->common.cpu_bstats), skb);
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ret = READ_ONCE(police->tcf_action);
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p = rcu_dereference_bh(police->params);
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if (p->tcfp_ewma_rate) {
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struct gnet_stats_rate_est64 sample;
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if (!gen_estimator_read(&police->tcf_rate_est, &sample) ||
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sample.bps >= p->tcfp_ewma_rate)
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goto inc_overlimits;
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}
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if (qdisc_pkt_len(skb) <= p->tcfp_mtu) {
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if (!p->rate_present) {
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ret = p->tcfp_result;
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goto end;
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}
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now = ktime_get_ns();
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spin_lock_bh(&police->tcfp_lock);
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toks = min_t(s64, now - police->tcfp_t_c, p->tcfp_burst);
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if (p->peak_present) {
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ptoks = toks + police->tcfp_ptoks;
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if (ptoks > p->tcfp_mtu_ptoks)
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ptoks = p->tcfp_mtu_ptoks;
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ptoks -= (s64)psched_l2t_ns(&p->peak,
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qdisc_pkt_len(skb));
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}
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toks += police->tcfp_toks;
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if (toks > p->tcfp_burst)
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toks = p->tcfp_burst;
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toks -= (s64)psched_l2t_ns(&p->rate, qdisc_pkt_len(skb));
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if ((toks|ptoks) >= 0) {
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police->tcfp_t_c = now;
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police->tcfp_toks = toks;
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police->tcfp_ptoks = ptoks;
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spin_unlock_bh(&police->tcfp_lock);
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ret = p->tcfp_result;
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goto inc_drops;
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}
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spin_unlock_bh(&police->tcfp_lock);
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}
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inc_overlimits:
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qstats_overlimit_inc(this_cpu_ptr(police->common.cpu_qstats));
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inc_drops:
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if (ret == TC_ACT_SHOT)
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qstats_drop_inc(this_cpu_ptr(police->common.cpu_qstats));
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end:
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return ret;
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}
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static void tcf_police_cleanup(struct tc_action *a)
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{
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struct tcf_police *police = to_police(a);
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struct tcf_police_params *p;
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p = rcu_dereference_protected(police->params, 1);
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if (p)
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kfree_rcu(p, rcu);
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}
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static void tcf_police_stats_update(struct tc_action *a,
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u64 bytes, u32 packets,
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u64 lastuse, bool hw)
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{
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struct tcf_police *police = to_police(a);
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struct tcf_t *tm = &police->tcf_tm;
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_bstats_cpu_update(this_cpu_ptr(a->cpu_bstats), bytes, packets);
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if (hw)
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_bstats_cpu_update(this_cpu_ptr(a->cpu_bstats_hw),
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bytes, packets);
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tm->lastuse = max_t(u64, tm->lastuse, lastuse);
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}
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static int tcf_police_dump(struct sk_buff *skb, struct tc_action *a,
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int bind, int ref)
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{
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unsigned char *b = skb_tail_pointer(skb);
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struct tcf_police *police = to_police(a);
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struct tcf_police_params *p;
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struct tc_police opt = {
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.index = police->tcf_index,
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.refcnt = refcount_read(&police->tcf_refcnt) - ref,
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.bindcnt = atomic_read(&police->tcf_bindcnt) - bind,
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};
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struct tcf_t t;
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spin_lock_bh(&police->tcf_lock);
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opt.action = police->tcf_action;
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p = rcu_dereference_protected(police->params,
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lockdep_is_held(&police->tcf_lock));
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opt.mtu = p->tcfp_mtu;
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opt.burst = PSCHED_NS2TICKS(p->tcfp_burst);
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if (p->rate_present)
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psched_ratecfg_getrate(&opt.rate, &p->rate);
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if (p->peak_present)
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psched_ratecfg_getrate(&opt.peakrate, &p->peak);
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if (nla_put(skb, TCA_POLICE_TBF, sizeof(opt), &opt))
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goto nla_put_failure;
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if (p->tcfp_result &&
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nla_put_u32(skb, TCA_POLICE_RESULT, p->tcfp_result))
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goto nla_put_failure;
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if (p->tcfp_ewma_rate &&
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nla_put_u32(skb, TCA_POLICE_AVRATE, p->tcfp_ewma_rate))
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goto nla_put_failure;
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t.install = jiffies_to_clock_t(jiffies - police->tcf_tm.install);
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t.lastuse = jiffies_to_clock_t(jiffies - police->tcf_tm.lastuse);
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t.firstuse = jiffies_to_clock_t(jiffies - police->tcf_tm.firstuse);
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t.expires = jiffies_to_clock_t(police->tcf_tm.expires);
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if (nla_put_64bit(skb, TCA_POLICE_TM, sizeof(t), &t, TCA_POLICE_PAD))
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goto nla_put_failure;
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spin_unlock_bh(&police->tcf_lock);
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return skb->len;
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nla_put_failure:
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spin_unlock_bh(&police->tcf_lock);
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nlmsg_trim(skb, b);
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return -1;
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}
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static int tcf_police_search(struct net *net, struct tc_action **a, u32 index)
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{
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struct tc_action_net *tn = net_generic(net, police_net_id);
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return tcf_idr_search(tn, a, index);
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}
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MODULE_AUTHOR("Alexey Kuznetsov");
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MODULE_DESCRIPTION("Policing actions");
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MODULE_LICENSE("GPL");
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static struct tc_action_ops act_police_ops = {
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.kind = "police",
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.id = TCA_ID_POLICE,
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.owner = THIS_MODULE,
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.stats_update = tcf_police_stats_update,
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.act = tcf_police_act,
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.dump = tcf_police_dump,
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.init = tcf_police_init,
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.walk = tcf_police_walker,
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.lookup = tcf_police_search,
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.cleanup = tcf_police_cleanup,
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.size = sizeof(struct tcf_police),
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};
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static __net_init int police_init_net(struct net *net)
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{
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struct tc_action_net *tn = net_generic(net, police_net_id);
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return tc_action_net_init(tn, &act_police_ops);
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}
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static void __net_exit police_exit_net(struct list_head *net_list)
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{
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tc_action_net_exit(net_list, police_net_id);
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}
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static struct pernet_operations police_net_ops = {
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.init = police_init_net,
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.exit_batch = police_exit_net,
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.id = &police_net_id,
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.size = sizeof(struct tc_action_net),
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};
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static int __init police_init_module(void)
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{
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return tcf_register_action(&act_police_ops, &police_net_ops);
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}
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static void __exit police_cleanup_module(void)
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{
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tcf_unregister_action(&act_police_ops, &police_net_ops);
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}
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module_init(police_init_module);
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module_exit(police_cleanup_module);
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