On Wed, Jan 25, 2017 at 11:27 PM, Vladislav Yasevich
<vyasevich@xxxxxxxxx> wrote:
> On Tue, Jan 24, 2017 at 1:01 AM, Xin Long <lucien.xin@xxxxxxxxx> wrote:
>>
>> sctp_addr_id2transport is a function for sockopt to look up assoc by
>> address. As the address is from userspace, it can be a v4-mapped v6
>> address. But in sctp protocol stack, it always handles a v4-mapped
>> v6 address as a v4 address. So it's necessary to convert it to a v4
>> address before looking up assoc by address.
>>
>> This patch is to fix it by calling sctp_verify_addr in which it can do
>> this conversion before calling sctp_endpoint_lookup_assoc, just like
>> what sctp_sendmsg and __sctp_connect do for the address from users.
>>
>> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
>> ---
>> net/sctp/socket.c | 6 +++++-
>> 1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
>> index 318c678..37eeab7 100644
>> --- a/net/sctp/socket.c
>> +++ b/net/sctp/socket.c
>> @@ -235,8 +235,12 @@ static struct sctp_transport
>> *sctp_addr_id2transport(struct sock *sk,
>> sctp_assoc_t id)
>> {
>> struct sctp_association *addr_asoc = NULL, *id_asoc = NULL;
>> - struct sctp_transport *transport;
>> + struct sctp_af *af = sctp_get_af_specific(addr->ss_family);
>> union sctp_addr *laddr = (union sctp_addr *)addr;
>> + struct sctp_transport *transport;
>> +
>> + if (sctp_verify_addr(sk, laddr, af->sockaddr_len))
>> + return NULL;
>>
>
> This causes a side-effect such that GET options will end up with ipv4
> address instead
> of a v4mapped address that was passed in.
not really
(more below)
>
> -vlad
>
>>
>> addr_asoc = sctp_endpoint_lookup_assoc(sctp_sk(sk)->ep,
>> laddr,
sctp_get_pf_specific(sk->sk_family)->addr_to_user(sctp_sk(sk),
(union sctp_addr *)addr);
here it will convert it back to v4mapped v6 address.
>> --
>> 2.1.0
>>
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>
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