[ovs-discuss] [PATCH ] ofproto: Fix for ovs-vswitchd crash on flow-mod with unsupported action
parameswaran krishnamurthy
parkrish at gmail.com
Tue Mar 5 12:45:54 UTC 2019
Problem Description:
The ovs-vswitchd is crashing while invoking flow-mod with upsupported
action(Tested with ovs2.10.1)
Steps to recreate:
Step 1) Create a flow
ovs-ofctl add-flow switch1
priority=228,dl_type=0x0800,dl_vlan="600",in_port=25,actions=output:ALL
This step is successful.
Step 2) Invoke flow-mod with incorrect contents.
ovs-ofctl mod-flows switch1
priority=228,dl_type=0x0800,dl_vlan="600",in_port=25,actions=output:ALL,mod_vlan_vid:50,mod_vlan_pcp=6,mod_nw_tos=16
In the above example, the ofproto provider I have, will return error for
rule_construct as set_fields come after Output.
However the OVS is ignoring the error (The return value of add_flow_init
is ignored in modify_flow_init_strict) and eventually the ovs-vswitched
crashes.
Crash backtrace:
-----------------------
Thread 1 "ovs-vswitchd" received signal SIGSEGV, Segmentation fault.
0x00007f6a06e785fb in modify_flows_start__ (
ofproto=ofproto at entry=0x55b289cecc28, ofm=ofm at entry=0x7ffdf7d57b70)
at ofproto/ofproto.c:5402
5402 in ofproto/ofproto.c
(gdb) bt
#0 0x00007f6a06e785fb in modify_flows_start__ (
ofproto=ofproto at entry=0x55b289cecc28, ofm=ofm at entry=0x7ffdf7d57b70)
at ofproto/ofproto.c:5402
#1 0x00007f6a06e790db in modify_flows_start_loose (ofm=0x7ffdf7d57b70,
ofproto=0x55b289cecc28) at ofproto/ofproto.c:5443
#2 ofproto_flow_mod_start (ofproto=ofproto at entry=0x55b289cecc28,
ofm=ofm at entry=0x7ffdf7d57b70) at ofproto/ofproto.c:7672
#3 0x00007f6a06e79164 in handle_flow_mod__ (
ofproto=ofproto at entry=0x55b289cecc28, fm=fm at entry=0x7ffdf7d57d20,
req=req at entry=0x7ffdf7d57cd0) at ofproto/ofproto.c:5858
#4 0x00007f6a06e792c2 in handle_flow_mod (ofconn=ofconn at entry
=0x55b289d528c0,
oh=oh at entry=0x55b289d5a410) at ofproto/ofproto.c:5835
#5 0x00007f6a06e7a173 in handle_openflow__ (msg=0x55b289d351d0,
ofconn=0x55b289d528c0) at ofproto/ofproto.c:8127
#6 handle_openflow (ofconn=0x55b289d528c0, ofp_msg=0x55b289d351d0)
at ofproto/ofproto.c:8296
#7 0x00007f6a06e6a013 in ofconn_run (
handle_openflow=0x7f6a06e796f0 <handle_openflow>,
ofconn=0x55b289d528c0)
at ofproto/connmgr.c:1446
#8 connmgr_run (mgr=0x55b289d14fe0,
handle_openflow=handle_openflow at entry=0x7f6a06e796f0
handle_openflow>)
at ofproto/connmgr.c:365
#9 0x00007f6a06e73056 in ofproto_run (p=0x55b289cecc28)
Fix:
------
In modify_flow_init_strict and modify_flow_init_loose instead of
blindly returning 0, the fix returns the value returned by
add_flow_init.
Testing:
----------
The flow-mod that was causing the crash get properly rejected with the
fix and no crash occurred.
Patch
----------
diff -uNr '--exclude=*.o' openvswitch-2.10.1/ofproto/ofproto.c
openvswitch-2.10.1_modified/ofproto/ofproto.c
--- openvswitch-2.10.1/ofproto/ofproto.c 2018-10-19 15:57:46.650077822 -0700
+++ openvswitch-2.10.1_modified/ofproto/ofproto.c 2019-03-05
00:16:27.436754000 -0800
@@ -5410,6 +5410,7 @@
const struct ofputil_flow_mod *fm)
OVS_EXCLUDED(ofproto_mutex)
{
+ enum ofperr error;
rule_criteria_init(&ofm->criteria, fm->table_id, &fm->match, 0,
OVS_VERSION_MAX, fm->cookie, fm->cookie_mask, OFPP_ANY,
OFPG_ANY);
@@ -5417,9 +5418,9 @@
(fm->flags & OFPUTIL_FF_NO_READONLY) != 0);
/* Must create a new flow in advance for the case that no matches are
* found. Also used for template for multiple modified flows. */
- add_flow_init(ofproto, ofm, fm);
+ error = add_flow_init(ofproto, ofm, fm);
- return 0;
+ return error;
}
/* Implements OFPFC_MODIFY. Returns 0 on success or an OpenFlow error code on
@@ -5495,6 +5496,7 @@
const struct ofputil_flow_mod *fm)
OVS_EXCLUDED(ofproto_mutex)
{
+ enum ofperr error;
rule_criteria_init(&ofm->criteria, fm->table_id, &fm->match, fm->priority,
OVS_VERSION_MAX, fm->cookie, fm->cookie_mask, OFPP_ANY,
OFPG_ANY);
@@ -5502,9 +5504,9 @@
(fm->flags & OFPUTIL_FF_NO_READONLY) != 0);
/* Must create a new flow in advance for the case that no matches are
* found. Also used for template for multiple modified flows. */
- add_flow_init(ofproto, ofm, fm);
+ error = add_flow_init(ofproto, ofm, fm);
- return 0;
+ return error;
}
/* Implements OFPFC_MODIFY_STRICT. Returns 0 on success or an OpenFlow error
Signed-off-by: Parameswaran Krishnamurthy <parkrish at gmail.com>
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