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| author | Davide Caratti <dcaratti@redhat.com> | 2019-10-12 13:55:07 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-10-15 17:14:48 -0700 |
| commit | fa4e0f8855fcba600e0be2575ee29c69166f74bd (patch) | |
| tree | 3224a12d0c83472a92df41f3dfff6c48b6fd1f64 /net/sched | |
| parent | dedc5a08da07874c6e0d411e7f39c5c2cf137014 (diff) | |
| download | linux-fa4e0f8855fcba600e0be2575ee29c69166f74bd.tar.gz linux-fa4e0f8855fcba600e0be2575ee29c69166f74bd.tar.bz2 linux-fa4e0f8855fcba600e0be2575ee29c69166f74bd.zip | |
net/sched: fix corrupted L2 header with MPLS 'push' and 'pop' actions
the following script:
# tc qdisc add dev eth0 clsact
# tc filter add dev eth0 egress protocol ip matchall \
> action mpls push protocol mpls_uc label 0x355aa bos 1
causes corruption of all IP packets transmitted by eth0. On TC egress, we
can't rely on the value of skb->mac_len, because it's 0 and a MPLS 'push'
operation will result in an overwrite of the first 4 octets in the packet
L2 header (e.g. the Destination Address if eth0 is an Ethernet); the same
error pattern is present also in the MPLS 'pop' operation. Fix this error
in act_mpls data plane, computing 'mac_len' as the difference between the
network header and the mac header (when not at TC ingress), and use it in
MPLS 'push'/'pop' core functions.
v2: unbreak 'make htmldocs' because of missing documentation of 'mac_len'
in skb_mpls_pop(), reported by kbuild test robot
CC: Lorenzo Bianconi <lorenzo@kernel.org>
Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC")
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Acked-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
| -rw-r--r-- | net/sched/act_mpls.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/net/sched/act_mpls.c b/net/sched/act_mpls.c index e168df0e008a..4cf6c553bb0b 100644 --- a/net/sched/act_mpls.c +++ b/net/sched/act_mpls.c @@ -55,7 +55,7 @@ static int tcf_mpls_act(struct sk_buff *skb, const struct tc_action *a, struct tcf_mpls *m = to_mpls(a); struct tcf_mpls_params *p; __be32 new_lse; - int ret; + int ret, mac_len; tcf_lastuse_update(&m->tcf_tm); bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb); @@ -63,8 +63,12 @@ static int tcf_mpls_act(struct sk_buff *skb, const struct tc_action *a, /* Ensure 'data' points at mac_header prior calling mpls manipulating * functions. */ - if (skb_at_tc_ingress(skb)) + if (skb_at_tc_ingress(skb)) { skb_push_rcsum(skb, skb->mac_len); + mac_len = skb->mac_len; + } else { + mac_len = skb_network_header(skb) - skb_mac_header(skb); + } ret = READ_ONCE(m->tcf_action); @@ -72,12 +76,12 @@ static int tcf_mpls_act(struct sk_buff *skb, const struct tc_action *a, switch (p->tcfm_action) { case TCA_MPLS_ACT_POP: - if (skb_mpls_pop(skb, p->tcfm_proto)) + if (skb_mpls_pop(skb, p->tcfm_proto, mac_len)) goto drop; break; case TCA_MPLS_ACT_PUSH: new_lse = tcf_mpls_get_lse(NULL, p, !eth_p_mpls(skb->protocol)); - if (skb_mpls_push(skb, new_lse, p->tcfm_proto)) + if (skb_mpls_push(skb, new_lse, p->tcfm_proto, mac_len)) goto drop; break; case TCA_MPLS_ACT_MODIFY: |