[ovs-dev] [PATCH 1/5] netdev-linux: Fix use of uninitialized LAG master name.

Ilya Maximets i.maximets at ovn.org
Mon May 24 19:43:24 UTC 2021


On 5/20/21 6:43 PM, Mark Gray wrote:
> On 04/04/2021 18:31, Ilya Maximets wrote:
>> 'if_indextoname' may fail leaving the 'master_name' uninitialized:
>>
>>  Conditional jump or move depends on uninitialised value(s)
>>     at 0x4C34329: strlen (vg_replace_strmem.c:459)
>>     by 0x51C638: hash_string (hash.h:342)
>>     by 0x51C638: hash_name (shash.c:28)
>>     by 0x51CC51: shash_find (shash.c:231)
>>     by 0x51CD38: shash_find_data (shash.c:245)
>>     by 0x4A797F: netdev_from_name (netdev.c:2013)
>>     by 0x544148: netdev_linux_update_lag (netdev-linux.c:676)
>>     by 0x544148: netdev_linux_run (netdev-linux.c:769)
>>     by 0x4A5997: netdev_run (netdev.c:186)
>>     by 0x40752B: main (ovs-vswitchd.c:129)
>>   Uninitialised value was created by a stack allocation
>>     at 0x543AFA: netdev_linux_run (netdev-linux.c:722)
>>
>> CC: John Hurley <john.hurley at netronome.com>
>> Fixes: d22f8927c3c9 ("netdev-linux: monitor and offload LAG slaves to TC")
>> Signed-off-by: Ilya Maximets <i.maximets at ovn.org>
>> ---
>>  lib/netdev-linux.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
>> index 15b25084b..2b8283e94 100644
>> --- a/lib/netdev-linux.c
>> +++ b/lib/netdev-linux.c
>> @@ -672,7 +672,9 @@ netdev_linux_update_lag(struct rtnetlink_change *change)
>>              uint32_t block_id;
>>              int error = 0;
>>  
>> -            if_indextoname(change->master_ifindex, master_name);
>> +            if (!if_indextoname(change->master_ifindex, master_name)) {
>> +                return;
>> +            }
>>              master_netdev = netdev_from_name(master_name);
>>              if (!master_netdev) {
>>                  return;
>>
> Interesting that strlen() doesn't check for NULL. LGTM
> 
> Acked-by: Mark D. Gray <mark.d.gray at redhat.com>
> 

Thanks!  Applied to master and backported down to 2.12.

Best regards, Ilya Maximets.


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