[ovs-dev] [PATCH ovn] binding: Cleanup gateway port local binding in runtime data.

Ilya Maximets i.maximets at ovn.org
Tue Nov 24 11:01:10 UTC 2020


On 11/20/20 4:37 PM, Dumitru Ceara wrote:
> When a port binding of type "l3gateway" is claimed its remote peer
> port_binding is also stored in local_datapath.peer_ports[].remote.
> 
> If the remote peer port_binding is deleted first (i.e., before the local
> "l3gateway" one) then we need to remove the complete
> local_datapath.peer_ports[] entry in order to avoid ending up using
> dangling pointers to already freed port bindings.
> 
> Also, properly reset local_datapath->has_local_l3gateway in
> remove_pb_from_local_datapath().
> 
> Ilya reported this issue found by AddressSanitizer during his testing:
> 
> ==1816017==ERROR: AddressSanitizer: heap-use-after-free on address 0x6140000cb170 at pc 0x0000005ab574 bp 0x7fff68925a30 sp 0x7fff68925a28
> READ of size 8 at 0x6140000cb170 thread T0
>     #0 0x5ab573 in put_replace_chassis_mac_flows git/ovn/controller/physical.c:550:9
>     #1 0x5a65eb in consider_port_binding git/ovn/controller/physical.c:1168:13
>     #2 0x5a8764 in physical_run git/ovn/controller/physical.c:1607:9
>     #3 0x5a0064 in flow_output_physical_flow_changes_handler git/ovn/controller/ovn-controller.c:2127:9
>     #4 0x5db423 in engine_compute git/ovn/lib/inc-proc-eng.c:306:18
>     #5 0x5dae1f in engine_run_node git/ovn/lib/inc-proc-eng.c:352:14
>     #6 0x5dac74 in engine_run git/ovn/lib/inc-proc-eng.c:377:9
>     #7 0x59ad64 in main git/ovn/controller/ovn-controller.c
>     #8 0x7f39fa6491a2 in __libc_start_main (/lib64/libc.so.6+0x271a2)
>     #9 0x480b2d in _start (git/ovn/controller/ovn-controller+0x480b2d)
> 
> 0x6140000cb170 is located 304 bytes inside of 408-byte region [0x6140000cb040,0x6140000cb1d8)
> freed by thread T0 here:
>     #0 0x520d07 in free (git/ovn/controller/ovn-controller+0x520d07)
>     #1 0x712de7 in ovsdb_idl_db_track_clear git/ovs/lib/ovsdb-idl.c:1984:21
>     #2 0x59b5cd in main git/ovn/controller/ovn-controller.c:2762:9
>     #3 0x7f39fa6491a2 in __libc_start_main (/lib64/libc.so.6+0x271a2)
> 
> Reported-by: Ilya Maximets <i.maximets at ovn.org>
> Fixes: 354bdba51abf ("ovn-controller: I-P for SB port binding and OVS interface in runtime_data.")
> Signed-off-by: Dumitru Ceara <dceara at redhat.com>
> ---

I do not know this part of the code well enough to ack, but
this patch fixes the issue for me.  Thanks!

Tested-by: Ilya Maximets <i.maximets at ovn.org>

Best regards, Ilya Maximets.


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