![Shmulik Ladkani](/assets/img/avatar_default.png)
Generic skb_vlan_push/skb_vlan_pop functions don't properly handle the case where the input skb data pointer does not point at the mac header: - They're doing push/pop, but fail to properly unwind data back to its original location. For example, in the skb_vlan_push case, any subsequent 'skb_push(skb, skb->mac_len)' calls make the skb->data point 4 bytes BEFORE start of frame, leading to bogus frames that may be transmitted. - They update rcsum per the added/removed 4 bytes tag. Alas if data is originally after the vlan/eth headers, then these bytes were already pulled out of the csum. OTOH calling skb_vlan_push/skb_vlan_pop with skb->data at mac_header present no issues. act_vlan is the only caller to skb_vlan_*() that has skb->data pointing at network header (upon ingress). Other calles (ovs, bpf) already adjust skb->data at mac_header. This patch fixes act_vlan to point to the mac_header prior calling skb_vlan_*() functions, as other callers do. Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Pravin Shelar <pshelar@ovn.org> Cc: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
307 lines
7.2 KiB
C
307 lines
7.2 KiB
C
/*
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* Copyright (c) 2014 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/if_vlan.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_vlan.h>
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#include <net/tc_act/tc_vlan.h>
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#define VLAN_TAB_MASK 15
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static int vlan_net_id;
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static struct tc_action_ops act_vlan_ops;
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static int tcf_vlan(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_vlan *v = to_vlan(a);
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int action;
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int err;
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u16 tci;
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spin_lock(&v->tcf_lock);
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tcf_lastuse_update(&v->tcf_tm);
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bstats_update(&v->tcf_bstats, skb);
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action = v->tcf_action;
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/* Ensure 'data' points at mac_header prior calling vlan manipulating
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* functions.
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*/
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if (skb_at_tc_ingress(skb))
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skb_push_rcsum(skb, skb->mac_len);
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switch (v->tcfv_action) {
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case TCA_VLAN_ACT_POP:
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err = skb_vlan_pop(skb);
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if (err)
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goto drop;
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break;
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case TCA_VLAN_ACT_PUSH:
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err = skb_vlan_push(skb, v->tcfv_push_proto, v->tcfv_push_vid |
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(v->tcfv_push_prio << VLAN_PRIO_SHIFT));
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if (err)
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goto drop;
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break;
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case TCA_VLAN_ACT_MODIFY:
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/* No-op if no vlan tag (either hw-accel or in-payload) */
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if (!skb_vlan_tagged(skb))
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goto unlock;
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/* extract existing tag (and guarantee no hw-accel tag) */
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if (skb_vlan_tag_present(skb)) {
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tci = skb_vlan_tag_get(skb);
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skb->vlan_tci = 0;
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} else {
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/* in-payload vlan tag, pop it */
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err = __skb_vlan_pop(skb, &tci);
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if (err)
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goto drop;
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}
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/* replace the vid */
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tci = (tci & ~VLAN_VID_MASK) | v->tcfv_push_vid;
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/* replace prio bits, if tcfv_push_prio specified */
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if (v->tcfv_push_prio) {
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tci &= ~VLAN_PRIO_MASK;
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tci |= v->tcfv_push_prio << VLAN_PRIO_SHIFT;
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}
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/* put updated tci as hwaccel tag */
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__vlan_hwaccel_put_tag(skb, v->tcfv_push_proto, tci);
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break;
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default:
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BUG();
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}
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goto unlock;
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drop:
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action = TC_ACT_SHOT;
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v->tcf_qstats.drops++;
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unlock:
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if (skb_at_tc_ingress(skb))
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skb_pull_rcsum(skb, skb->mac_len);
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spin_unlock(&v->tcf_lock);
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return action;
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}
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static const struct nla_policy vlan_policy[TCA_VLAN_MAX + 1] = {
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[TCA_VLAN_PARMS] = { .len = sizeof(struct tc_vlan) },
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[TCA_VLAN_PUSH_VLAN_ID] = { .type = NLA_U16 },
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[TCA_VLAN_PUSH_VLAN_PROTOCOL] = { .type = NLA_U16 },
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[TCA_VLAN_PUSH_VLAN_PRIORITY] = { .type = NLA_U8 },
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};
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static int tcf_vlan_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 tc_action_net *tn = net_generic(net, vlan_net_id);
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struct nlattr *tb[TCA_VLAN_MAX + 1];
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struct tc_vlan *parm;
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struct tcf_vlan *v;
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int action;
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__be16 push_vid = 0;
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__be16 push_proto = 0;
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u8 push_prio = 0;
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bool exists = false;
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int ret = 0, err;
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if (!nla)
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return -EINVAL;
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err = nla_parse_nested(tb, TCA_VLAN_MAX, nla, vlan_policy);
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if (err < 0)
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return err;
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if (!tb[TCA_VLAN_PARMS])
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return -EINVAL;
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parm = nla_data(tb[TCA_VLAN_PARMS]);
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exists = tcf_hash_check(tn, parm->index, a, bind);
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if (exists && bind)
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return 0;
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switch (parm->v_action) {
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case TCA_VLAN_ACT_POP:
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break;
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case TCA_VLAN_ACT_PUSH:
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case TCA_VLAN_ACT_MODIFY:
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if (!tb[TCA_VLAN_PUSH_VLAN_ID]) {
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if (exists)
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tcf_hash_release(*a, bind);
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return -EINVAL;
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}
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push_vid = nla_get_u16(tb[TCA_VLAN_PUSH_VLAN_ID]);
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if (push_vid >= VLAN_VID_MASK) {
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if (exists)
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tcf_hash_release(*a, bind);
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return -ERANGE;
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}
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if (tb[TCA_VLAN_PUSH_VLAN_PROTOCOL]) {
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push_proto = nla_get_be16(tb[TCA_VLAN_PUSH_VLAN_PROTOCOL]);
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switch (push_proto) {
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case htons(ETH_P_8021Q):
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case htons(ETH_P_8021AD):
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break;
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default:
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return -EPROTONOSUPPORT;
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}
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} else {
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push_proto = htons(ETH_P_8021Q);
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}
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if (tb[TCA_VLAN_PUSH_VLAN_PRIORITY])
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push_prio = nla_get_u8(tb[TCA_VLAN_PUSH_VLAN_PRIORITY]);
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break;
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default:
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if (exists)
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tcf_hash_release(*a, bind);
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return -EINVAL;
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}
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action = parm->v_action;
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if (!exists) {
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ret = tcf_hash_create(tn, parm->index, est, a,
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&act_vlan_ops, bind, false);
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if (ret)
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return ret;
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ret = ACT_P_CREATED;
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} else {
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tcf_hash_release(*a, bind);
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if (!ovr)
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return -EEXIST;
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}
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v = to_vlan(*a);
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spin_lock_bh(&v->tcf_lock);
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v->tcfv_action = action;
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v->tcfv_push_vid = push_vid;
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v->tcfv_push_prio = push_prio;
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v->tcfv_push_proto = push_proto;
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v->tcf_action = parm->action;
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spin_unlock_bh(&v->tcf_lock);
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if (ret == ACT_P_CREATED)
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tcf_hash_insert(tn, *a);
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return ret;
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}
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static int tcf_vlan_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_vlan *v = to_vlan(a);
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struct tc_vlan opt = {
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.index = v->tcf_index,
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.refcnt = v->tcf_refcnt - ref,
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.bindcnt = v->tcf_bindcnt - bind,
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.action = v->tcf_action,
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.v_action = v->tcfv_action,
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};
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struct tcf_t t;
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if (nla_put(skb, TCA_VLAN_PARMS, sizeof(opt), &opt))
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goto nla_put_failure;
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if ((v->tcfv_action == TCA_VLAN_ACT_PUSH ||
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v->tcfv_action == TCA_VLAN_ACT_MODIFY) &&
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(nla_put_u16(skb, TCA_VLAN_PUSH_VLAN_ID, v->tcfv_push_vid) ||
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nla_put_be16(skb, TCA_VLAN_PUSH_VLAN_PROTOCOL,
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v->tcfv_push_proto) ||
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(nla_put_u8(skb, TCA_VLAN_PUSH_VLAN_PRIORITY,
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v->tcfv_push_prio))))
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goto nla_put_failure;
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tcf_tm_dump(&t, &v->tcf_tm);
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if (nla_put_64bit(skb, TCA_VLAN_TM, sizeof(t), &t, TCA_VLAN_PAD))
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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, b);
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return -1;
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}
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static int tcf_vlan_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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{
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struct tc_action_net *tn = net_generic(net, vlan_net_id);
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return tcf_generic_walker(tn, skb, cb, type, ops);
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}
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static int tcf_vlan_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, vlan_net_id);
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return tcf_hash_search(tn, a, index);
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}
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static struct tc_action_ops act_vlan_ops = {
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.kind = "vlan",
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.type = TCA_ACT_VLAN,
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.owner = THIS_MODULE,
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.act = tcf_vlan,
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.dump = tcf_vlan_dump,
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.init = tcf_vlan_init,
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.walk = tcf_vlan_walker,
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.lookup = tcf_vlan_search,
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.size = sizeof(struct tcf_vlan),
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};
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static __net_init int vlan_init_net(struct net *net)
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{
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struct tc_action_net *tn = net_generic(net, vlan_net_id);
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return tc_action_net_init(tn, &act_vlan_ops, VLAN_TAB_MASK);
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}
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static void __net_exit vlan_exit_net(struct net *net)
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{
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struct tc_action_net *tn = net_generic(net, vlan_net_id);
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tc_action_net_exit(tn);
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}
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static struct pernet_operations vlan_net_ops = {
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.init = vlan_init_net,
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.exit = vlan_exit_net,
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.id = &vlan_net_id,
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.size = sizeof(struct tc_action_net),
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};
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static int __init vlan_init_module(void)
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{
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return tcf_register_action(&act_vlan_ops, &vlan_net_ops);
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}
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static void __exit vlan_cleanup_module(void)
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{
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tcf_unregister_action(&act_vlan_ops, &vlan_net_ops);
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}
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module_init(vlan_init_module);
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module_exit(vlan_cleanup_module);
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MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
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MODULE_DESCRIPTION("vlan manipulation actions");
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MODULE_LICENSE("GPL v2");
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