![Daniel Borkmann](/assets/img/avatar_default.png)
Similarly as in cls_bpf, also this code needs to reject mismatches.
Reference: http://article.gmane.org/gmane.linux.network/347406
Fixes: d23b8ad8ab
("tc: add BPF based action")
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
209 lines
4.8 KiB
C
209 lines
4.8 KiB
C
/*
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* Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include <linux/rtnetlink.h>
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#include <linux/filter.h>
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#include <net/netlink.h>
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#include <net/pkt_sched.h>
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#include <linux/tc_act/tc_bpf.h>
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#include <net/tc_act/tc_bpf.h>
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#define BPF_TAB_MASK 15
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static int tcf_bpf(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_bpf *b = a->priv;
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int action;
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int filter_res;
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spin_lock(&b->tcf_lock);
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b->tcf_tm.lastuse = jiffies;
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bstats_update(&b->tcf_bstats, skb);
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action = b->tcf_action;
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filter_res = BPF_PROG_RUN(b->filter, skb);
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if (filter_res == 0) {
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/* Return code 0 from the BPF program
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* is being interpreted as a drop here.
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*/
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action = TC_ACT_SHOT;
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b->tcf_qstats.drops++;
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}
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spin_unlock(&b->tcf_lock);
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return action;
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}
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static int tcf_bpf_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 *tp = skb_tail_pointer(skb);
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struct tcf_bpf *b = a->priv;
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struct tc_act_bpf opt = {
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.index = b->tcf_index,
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.refcnt = b->tcf_refcnt - ref,
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.bindcnt = b->tcf_bindcnt - bind,
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.action = b->tcf_action,
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};
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struct tcf_t t;
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struct nlattr *nla;
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if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt))
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goto nla_put_failure;
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if (nla_put_u16(skb, TCA_ACT_BPF_OPS_LEN, b->bpf_num_ops))
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goto nla_put_failure;
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nla = nla_reserve(skb, TCA_ACT_BPF_OPS, b->bpf_num_ops *
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sizeof(struct sock_filter));
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if (!nla)
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goto nla_put_failure;
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memcpy(nla_data(nla), b->bpf_ops, nla_len(nla));
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t.install = jiffies_to_clock_t(jiffies - b->tcf_tm.install);
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t.lastuse = jiffies_to_clock_t(jiffies - b->tcf_tm.lastuse);
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t.expires = jiffies_to_clock_t(b->tcf_tm.expires);
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if (nla_put(skb, TCA_ACT_BPF_TM, sizeof(t), &t))
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goto nla_put_failure;
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return skb->len;
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nla_put_failure:
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nlmsg_trim(skb, tp);
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return -1;
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}
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static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = {
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[TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) },
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[TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 },
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[TCA_ACT_BPF_OPS] = { .type = NLA_BINARY,
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.len = sizeof(struct sock_filter) * BPF_MAXINSNS },
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};
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static int tcf_bpf_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)
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{
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struct nlattr *tb[TCA_ACT_BPF_MAX + 1];
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struct tc_act_bpf *parm;
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struct tcf_bpf *b;
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u16 bpf_size, bpf_num_ops;
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struct sock_filter *bpf_ops;
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struct sock_fprog_kern tmp;
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struct bpf_prog *fp;
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int ret;
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if (!nla)
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return -EINVAL;
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ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy);
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if (ret < 0)
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return ret;
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if (!tb[TCA_ACT_BPF_PARMS] ||
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!tb[TCA_ACT_BPF_OPS_LEN] || !tb[TCA_ACT_BPF_OPS])
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return -EINVAL;
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parm = nla_data(tb[TCA_ACT_BPF_PARMS]);
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bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]);
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if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
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return -EINVAL;
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bpf_size = bpf_num_ops * sizeof(*bpf_ops);
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if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS]))
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return -EINVAL;
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bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
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if (!bpf_ops)
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return -ENOMEM;
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memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size);
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tmp.len = bpf_num_ops;
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tmp.filter = bpf_ops;
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ret = bpf_prog_create(&fp, &tmp);
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if (ret)
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goto free_bpf_ops;
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if (!tcf_hash_check(parm->index, a, bind)) {
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ret = tcf_hash_create(parm->index, est, a, sizeof(*b), bind);
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if (ret)
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goto destroy_fp;
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ret = ACT_P_CREATED;
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} else {
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if (bind)
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goto destroy_fp;
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tcf_hash_release(a, bind);
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if (!ovr) {
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ret = -EEXIST;
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goto destroy_fp;
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}
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}
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b = to_bpf(a);
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spin_lock_bh(&b->tcf_lock);
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b->tcf_action = parm->action;
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b->bpf_num_ops = bpf_num_ops;
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b->bpf_ops = bpf_ops;
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b->filter = fp;
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spin_unlock_bh(&b->tcf_lock);
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if (ret == ACT_P_CREATED)
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tcf_hash_insert(a);
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return ret;
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destroy_fp:
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bpf_prog_destroy(fp);
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free_bpf_ops:
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kfree(bpf_ops);
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return ret;
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}
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static void tcf_bpf_cleanup(struct tc_action *a, int bind)
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{
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struct tcf_bpf *b = a->priv;
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bpf_prog_destroy(b->filter);
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}
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static struct tc_action_ops act_bpf_ops = {
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.kind = "bpf",
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.type = TCA_ACT_BPF,
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.owner = THIS_MODULE,
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.act = tcf_bpf,
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.dump = tcf_bpf_dump,
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.cleanup = tcf_bpf_cleanup,
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.init = tcf_bpf_init,
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};
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static int __init bpf_init_module(void)
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{
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return tcf_register_action(&act_bpf_ops, BPF_TAB_MASK);
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}
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static void __exit bpf_cleanup_module(void)
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{
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tcf_unregister_action(&act_bpf_ops);
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}
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module_init(bpf_init_module);
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module_exit(bpf_cleanup_module);
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MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
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MODULE_DESCRIPTION("TC BPF based action");
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MODULE_LICENSE("GPL v2");
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