sctp: process duplicated strreset in and addstrm in requests correctly
This patch is to fix the replay attack issue for strreset and addstrm in requests. When a duplicated strreset in or addstrm in request is received, reply it with bad seqno if it's seqno < asoc->strreset_inseq - 2, and reply it with the result saved in asoc if it's seqno >= asoc->strreset_inseq - 2. For strreset in or addstrm in request, if the receiver side processes it successfully, a strreset out or addstrm out request(as a response for that request) will be sent back to peer. reconf_time will retransmit the out request even if it's lost. So when receiving a duplicated strreset in or addstrm in request and it's result was performed, it shouldn't reply this request, but drop it instead. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -456,12 +456,18 @@ struct sctp_chunk *sctp_process_strreset_inreq(
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__u32 request_seq;
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request_seq = ntohl(inreq->request_seq);
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if (request_seq > asoc->strreset_inseq) {
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if (TSN_lt(asoc->strreset_inseq, request_seq) ||
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TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
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result = SCTP_STRRESET_ERR_BAD_SEQNO;
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goto out;
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} else if (request_seq == asoc->strreset_inseq) {
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asoc->strreset_inseq++;
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goto err;
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} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
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i = asoc->strreset_inseq - request_seq - 1;
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result = asoc->strreset_result[i];
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if (result == SCTP_STRRESET_PERFORMED)
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return NULL;
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goto err;
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}
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asoc->strreset_inseq++;
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if (!(asoc->strreset_enable & SCTP_ENABLE_RESET_STREAM_REQ))
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goto out;
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@ -496,10 +502,14 @@ struct sctp_chunk *sctp_process_strreset_inreq(
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asoc->strreset_outstanding = 1;
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sctp_chunk_hold(asoc->strreset_chunk);
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result = SCTP_STRRESET_PERFORMED;
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*evp = sctp_ulpevent_make_stream_reset_event(asoc,
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SCTP_STREAM_RESET_INCOMING_SSN, nums, str_p, GFP_ATOMIC);
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out:
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sctp_update_strreset_result(asoc, result);
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err:
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if (!chunk)
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chunk = sctp_make_strreset_resp(asoc, result, request_seq);
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@ -671,15 +681,21 @@ struct sctp_chunk *sctp_process_strreset_addstrm_in(
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struct sctp_stream_out *streamout;
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struct sctp_chunk *chunk = NULL;
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__u32 request_seq, outcnt;
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__u16 out;
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__u16 out, i;
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request_seq = ntohl(addstrm->request_seq);
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if (request_seq > asoc->strreset_inseq) {
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if (TSN_lt(asoc->strreset_inseq, request_seq) ||
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TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
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result = SCTP_STRRESET_ERR_BAD_SEQNO;
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goto out;
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} else if (request_seq == asoc->strreset_inseq) {
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asoc->strreset_inseq++;
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goto err;
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} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
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i = asoc->strreset_inseq - request_seq - 1;
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result = asoc->strreset_result[i];
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if (result == SCTP_STRRESET_PERFORMED)
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return NULL;
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goto err;
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}
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asoc->strreset_inseq++;
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if (!(asoc->strreset_enable & SCTP_ENABLE_CHANGE_ASSOC_REQ))
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goto out;
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@ -712,10 +728,14 @@ struct sctp_chunk *sctp_process_strreset_addstrm_in(
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stream->outcnt = outcnt;
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result = SCTP_STRRESET_PERFORMED;
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*evp = sctp_ulpevent_make_stream_change_event(asoc,
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0, 0, ntohs(addstrm->number_of_streams), GFP_ATOMIC);
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out:
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sctp_update_strreset_result(asoc, result);
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err:
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if (!chunk)
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chunk = sctp_make_strreset_resp(asoc, result, request_seq);
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