On 08/26/2015 05:09 PM, lucien xin wrote:
> On Thu, Aug 27, 2015 at 4:59 AM, Marcelo Ricardo Leitner
> <mleit...@redhat.com> wrote:
>> On Wed, Aug 26, 2015 at 04:42:21PM -0400, Vlad Yasevich wrote:
>>> On 08/26/2015 04:35 PM, Xin Long wrote:
>>>> in sctp_process_asconf(), we get address parameter from the beginning of
>>>> the addip params. but we never check if it's really there. if the addr
>>>> param is not there, it still can pass sctp_verify_asconf(), then to be
>>>> handled by sctp_process_asconf(), it will not be safe.
>>>>
>>>> so add a code in sctp_verify_asconf() to check the address parameter is in
>>>> the beginning, or return false to send abort.
>>>>
>>>> v2->v3:
>>>> * put the check in the loop, add the check for multiple address
>>>> parameters.
>>>
>>>
>>> Please split the multiple address detection from first address detection.
>>> They are 2 different bugs and each one deserves a separate commit and
>>> changelog.
>>
>> See below, thx.
>>
>>>
>>> Thanks
>>> -vlad
>>>
>>>> v1->v2:
>>>> * put the check behind the params' length verify.
>>>>
>>>> Signed-off-by: Xin Long <lucien....@gmail.com>
>>>> Signed-off-by: Vlad Yasevich <vyase...@redhat.com>
>>>> ---
>>>> net/sctp/sm_make_chunk.c | 14 ++++++++++++--
>>>> 1 file changed, 12 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
>>>> index 06320c8..4068fe1 100644
>>>> --- a/net/sctp/sm_make_chunk.c
>>>> +++ b/net/sctp/sm_make_chunk.c
>>>> @@ -3130,14 +3130,24 @@ bool sctp_verify_asconf(const struct
>>>> sctp_association *asoc,
>>>> case SCTP_PARAM_ERR_CAUSE:
>>>> break;
>>>> case SCTP_PARAM_IPV4_ADDRESS:
>>>> + if (addr_param_seen) {
>>>> + /* peer placed multiple address parameters into
>>>> + * the same asconf. reject it.
>>>> + */
>>>> + return false;
>>>> + }
>>>> if (length != sizeof(sctp_ipv4addr_param_t))
>>>> return false;
>>>> - addr_param_seen = true;
>>>> + if (param.v == addip->addip_hdr.params)
>>>> + addr_param_seen = true;
>>>> break;
>>
>> I know I had suggested using addr_param_seen to check for multiple
>> occurrences, but now realized we can simplify this with something like:
>>
>> + if (param.v != addip->addip_hdr.params)
>> + return false;
>> addr_param_seen = true;
>>
>> Then the check against addr_param_seen is not needed and do both checks
>> at once.
>>
> looks nice, Vlad ?
>
yes. This is fine too. I think this kills 2 bugs with 1 patch...
If you go this route, make sure to document this well in the change log.
-vlad
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