Re: [B.A.T.M.A.N.] [PATCH-maint] batman-adv: fix potential orig_node reference leak

["Martin Hundebøll" <martin@hundeboll.net>]

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On 2014-02-11 18:26, Antonio Quartulli wrote:
> On 08/02/14 16:45, Simon Wunderlich wrote:
>> Since batadv_orig_node_new() sets the refcount to two, assuming that
>> the calling function will use a reference for putting the orig_node into
>> a hash or similar, both references must be freed if initialization of
>> the orig_node fails. Otherwise that object may be leaked in that error
>> case.
>>
>> Reported-by: Antonio Quartulli <antonio@meshcoding.com>
>> Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
>> ---
>>  bat_iv_ogm.c |    2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/bat_iv_ogm.c b/bat_iv_ogm.c
>> index 6f4fcdc..6000337 100644
>> --- a/bat_iv_ogm.c
>> +++ b/bat_iv_ogm.c
>> @@ -256,6 +256,8 @@ batadv_iv_ogm_orig_get(struct batadv_priv *bat_priv, const uint8_t *addr)
>>  free_bcast_own:
>>  	kfree(orig_node->bat_iv.bcast_own);
>>  free_orig_node:
>> +	/* free twice, as batadv_orig_node_new set refcount to 2 */
>> +	batadv_orig_node_free_ref(orig_node);
>>  	batadv_orig_node_free_ref(orig_node);
> 
> Coudln't we just invoke kfree(orig_node) here ? I think that if we hit
> this point it is because the node has not added to the hash and
> therefore it i snot used in any other context. This way we avoid the
> double free_ref() and we don't trgger the whole RCU mechanism.
> 
> Or am I missing something?

batadv_<type>_free_ref() might have side effect that are not handled by
kfree alone...

-- 
Kind Regards
Martin Hundebøll
Frederiks Allé 99, 1.th
8000 Aarhus C
Denmark

+45 61 65 54 61
martin@hundeboll.net


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