[ovs-dev] [PATCH] odp: Fix crash in parse_8021q_onward().

[nickcooper-zhangtonghao]

When we use the 'ovs-appctl ofproto/trace' to send packets,
which include the 'vlan' field, but exclude the 'encap',
the ovs-vswitchd will crash. We should check 'encap' field
in parse_8021q_onward(), before using it.

ovs-appctl ofproto/trace ovs-system  \
    'in_port(1),eth(src=50:54:00:00:00:05,dst=50:54:00:00:00:07),
    eth_type(0x8100),vlan(vid=99,pcp=0)'

    #0  nl_attr_get_size (nla=nla at entry=0x0) at lib/netlink.c:567
    #1  parse_8021q_onward (src_flow=0x7ffd0ec77540, key_len=40,
        key=0x1207e00, flow=0x7ffd0ec77540, expected_attrs=<optimized out>,
        out_of_range_attr=0, present_attrs=120, attrs=0x7ffd0ec77170)
        at lib/odp-util.c:5359
    #2  odp_flow_key_to_flow__ (key=0x1207e00, key_len=40,
        flow=flow at entry=0x7ffd0ec77540, src_flow=src_flow at entry=0x7ffd0ec77540)
        at lib/odp-util.c:5520
    #3  odp_flow_key_to_flow (key=<optimized out>, key_len=<optimized out>,
        flow=flow at entry=0x7ffd0ec77540) at lib/odp-util.c:5555
    #4  parse_flow_and_packet (argc=3, argv=0x12b2220,
        ofprotop=ofprotop at entry=0x7ffd0ec77510, flow=flow at entry=0x7ffd0ec77540,
        packetp=packetp at entry=0x7ffd0ec77518)
        at ofproto/ofproto-dpif-trace.c:211
    #5  ofproto_unixctl_trace (conn=0x1268c20, argc=<optimized out>,
        argv=<optimized out>, aux=<optimized out>) at ofproto/ofproto-dpif-trace.c:309
    #6  process_command (request=<optimized out>, conn=0x1268c20) at lib/unixctl.c:313
    #7  run_connection (conn=0x1268c20) at lib/unixctl.c:347
    #8  unixctl_server_run (server=0x1180970) at lib/unixctl.c:400
    #9  main (argc=5, argv=0x7ffd0ec779c8) at vswitchd/ovs-vswitchd.c:120

Signed-off-by: nickcooper-zhangtonghao <nic at opencloud.tech>
---
 lib/odp-util.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/odp-util.c b/lib/odp-util.c
index dea5ab2..4aaf8e1 100644
--- a/lib/odp-util.c
+++ b/lib/odp-util.c
@@ -5335,7 +5335,8 @@ parse_8021q_onward(const struct nlattr *attrs[OVS_KEY_ATTR_MAX + 1],
                         ? nl_attr_get_be16(attrs[OVS_KEY_ATTR_VLAN])
                         : htons(0));
         if (!is_mask) {
-            if (!(present_attrs & (UINT64_C(1) << OVS_KEY_ATTR_VLAN))) {
+            if (!(present_attrs & (UINT64_C(1) << OVS_KEY_ATTR_VLAN)) ||
+                !(present_attrs & (UINT64_C(1) << OVS_KEY_ATTR_ENCAP))) {
                 return ODP_FIT_TOO_LITTLE;
             } else if (flow->vlans[encaps].tci == htons(0)) {
                 /* Corner case for a truncated 802.1Q header. */
-- 
1.8.3.1