[ovs-dev] [PATCH v2] odp-execute: Fix length checking while executing check_pkt_len action.

Ilya Maximets i.maximets at ovn.org
Fri Jun 26 10:51:10 UTC 2020


If dp-packet contains l2 padding or cutlen was applied to it, size will
be larger than the actual size of a payload and action will work
incorrectly.

Ex. Padding could be added during miniflow_extract() if detected.

CC: Numan Siddique <nusiddiq at redhat.com>
Fixes: 5b34f8fc3b38 ("Add a new OVS action check_pkt_larger")
Reported-by: Miroslav Kubiczek <miroslav.kubiczek at adaptivemobile.com>
Reported-at: https://mail.openvswitch.org/pipermail/ovs-discuss/2020-May/050157.html
Signed-off-by: Ilya Maximets <i.maximets at ovn.org>
---

Version 2:
  - Using dp_packet_get_send_len() to account cutlen.

 lib/odp-execute.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/odp-execute.c b/lib/odp-execute.c
index 6018e378a..6eeda2a61 100644
--- a/lib/odp-execute.c
+++ b/lib/odp-execute.c
@@ -761,10 +761,11 @@ odp_execute_check_pkt_len(void *dp, struct dp_packet *packet, bool steal,
 
     const struct nlattr *a;
     struct dp_packet_batch pb;
+    uint32_t size = dp_packet_get_send_len(packet)
+                    - dp_packet_l2_pad_size(packet);
 
     a = attrs[OVS_CHECK_PKT_LEN_ATTR_PKT_LEN];
-    bool is_greater = dp_packet_size(packet) > nl_attr_get_u16(a);
-    if (is_greater) {
+    if (size > nl_attr_get_u16(a)) {
         a = attrs[OVS_CHECK_PKT_LEN_ATTR_ACTIONS_IF_GREATER];
     } else {
         a = attrs[OVS_CHECK_PKT_LEN_ATTR_ACTIONS_IF_LESS_EQUAL];
-- 
2.25.4



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