| Message ID | 13e1c79da12f9c08739e1ba94361d203e2a6627d.1583939416.git.gnault@redhat.com |
|---|---|
| State | Accepted |
| Delegated to: | stephen hemminger |
| Headers | show |
| Series | [iproute2] iproute2: fix MPLS label parsing | expand |
On Wed, 11 Mar 2020 16:16:36 +0100 Guillaume Nault <gnault@redhat.com> wrote: > The initial value of "label" in parse_mpls() is 0xffffffff. Therefore > we should test for this value, and not 0, to detect if a label has been > provided. The "!label" test not only fails to detect a missing label > parameter, it also prevents the use of the IPv4 explicit NULL label, > which actually equals 0. > > Reproducer: > $ ip link add name dm0 type dummy > $ tc qdisc add dev dm0 ingress > > $ tc filter add dev dm0 parent ffff: matchall action mpls push > Error: act_mpls: Label is required for MPLS push. > We have an error talking to the kernel > --> Filter was pushed to the kernel, where it got rejected. > > $ tc filter add dev dm0 parent ffff: matchall action mpls push label 0 > Error: argument "label" is required > --> Label 0 was rejected by iproute2. > > Expected result: > $ tc filter add dev dm0 parent ffff: matchall action mpls push > Error: argument "label" is required > --> Filter was directly rejected by iproute2. > > $ tc filter add dev dm0 parent ffff: matchall action mpls push label 0 > --> Filter is accepted. > > Signed-off-by: Guillaume Nault <gnault@redhat.com> Applied, thanks
diff --git a/tc/m_mpls.c b/tc/m_mpls.c index 6f3a39f4..50eba01c 100644 --- a/tc/m_mpls.c +++ b/tc/m_mpls.c @@ -156,7 +156,7 @@ static int parse_mpls(struct action_util *a, int *argc_p, char ***argv_p, } } - if (action == TCA_MPLS_ACT_PUSH && !label) + if (action == TCA_MPLS_ACT_PUSH && label == 0xffffffff) missarg("label"); if (action == TCA_MPLS_ACT_PUSH && proto &&
The initial value of "label" in parse_mpls() is 0xffffffff. Therefore we should test for this value, and not 0, to detect if a label has been provided. The "!label" test not only fails to detect a missing label parameter, it also prevents the use of the IPv4 explicit NULL label, which actually equals 0. Reproducer: $ ip link add name dm0 type dummy $ tc qdisc add dev dm0 ingress $ tc filter add dev dm0 parent ffff: matchall action mpls push Error: act_mpls: Label is required for MPLS push. We have an error talking to the kernel --> Filter was pushed to the kernel, where it got rejected. $ tc filter add dev dm0 parent ffff: matchall action mpls push label 0 Error: argument "label" is required --> Label 0 was rejected by iproute2. Expected result: $ tc filter add dev dm0 parent ffff: matchall action mpls push Error: argument "label" is required --> Filter was directly rejected by iproute2. $ tc filter add dev dm0 parent ffff: matchall action mpls push label 0 --> Filter is accepted. Signed-off-by: Guillaume Nault <gnault@redhat.com> --- tc/m_mpls.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)