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authorShmulik Ladkani <sladkani@proofpoint.com>2019-12-25 10:51:01 +0200
committerDavid S. Miller <davem@davemloft.net>2019-12-27 16:35:32 -0800
commit70cf3dc7313207816255b9acb0dffb19dae78144 (patch)
tree70c0d31b107bf18fd277f6e582cf88bff57ee5a4 /net
parentbb3d0b8bf5be61ab1d6f472c43cbf34de17e796b (diff)
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net/sched: act_mirred: Pull mac prior redir to non mac_header_xmit device
There's no skb_pull performed when a mirred action is set at egress of a mac device, with a target device/action that expects skb->data to point at the network header. As a result, either the target device is errornously given an skb with data pointing to the mac (egress case), or the net stack receives the skb with data pointing to the mac (ingress case). E.g: # tc qdisc add dev eth9 root handle 1: prio # tc filter add dev eth9 parent 1: prio 9 protocol ip handle 9 basic \ action mirred egress redirect dev tun0 (tun0 is a tun device. result: tun0 errornously gets the eth header instead of the iph) Revise the push/pull logic of tcf_mirred_act() to not rely on the skb_at_tc_ingress() vs tcf_mirred_act_wants_ingress() comparison, as it does not cover all "pull" cases. Instead, calculate whether the required action on the target device requires the data to point at the network header, and compare this to whether skb->data points to network header - and make the push/pull adjustments as necessary. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Shmulik Ladkani <sladkani@proofpoint.com> Tested-by: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/sched/act_mirred.c22
1 files changed, 12 insertions, 10 deletions
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index 1e3eb3a97532..1ad300e6dbc0 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -219,8 +219,10 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a,
bool use_reinsert;
bool want_ingress;
bool is_redirect;
+ bool expects_nh;
int m_eaction;
int mac_len;
+ bool at_nh;
rec_level = __this_cpu_inc_return(mirred_rec_level);
if (unlikely(rec_level > MIRRED_RECURSION_LIMIT)) {
@@ -261,19 +263,19 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a,
goto out;
}
- /* If action's target direction differs than filter's direction,
- * and devices expect a mac header on xmit, then mac push/pull is
- * needed.
- */
want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
- if (skb_at_tc_ingress(skb) != want_ingress && m_mac_header_xmit) {
- if (!skb_at_tc_ingress(skb)) {
- /* caught at egress, act ingress: pull mac */
- mac_len = skb_network_header(skb) - skb_mac_header(skb);
+
+ expects_nh = want_ingress || !m_mac_header_xmit;
+ at_nh = skb->data == skb_network_header(skb);
+ if (at_nh != expects_nh) {
+ mac_len = skb_at_tc_ingress(skb) ? skb->mac_len :
+ skb_network_header(skb) - skb_mac_header(skb);
+ if (expects_nh) {
+ /* target device/action expect data at nh */
skb_pull_rcsum(skb2, mac_len);
} else {
- /* caught at ingress, act egress: push mac */
- skb_push_rcsum(skb2, skb->mac_len);
+ /* target device/action expect data at mac */
+ skb_push_rcsum(skb2, mac_len);
}
}