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Merge branch 'sctp-dup-stream-reconf-events'

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Xin Long says:

====================
sctp: add proper process for duplicated stream reconf requests

Now sctp stream reconf will process a request again even if it's seqno
is less than asoc->strreset_inseq. It may cause a replay attack.

This patchset is to avoid it by add proper process for all duplicated
stream reconf requests.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2017-04-18 13:39:51 -04:00
commit 3a9ca1e2cb
2 changed files with 74 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/net/sctp/structs.h
View File

@ -1889,6 +1889,7 @@ struct sctp_association {
__u32 strreset_outseq; /* Update after receiving response */
__u32 strreset_inseq; /* Update after receiving request */
__u32 strreset_result[2]; /* save the results of last 2 responses */
struct sctp_chunk *strreset_chunk; /* save request chunk */

96
net/sctp/stream.c
View File

@ -344,6 +344,13 @@ static sctp_paramhdr_t *sctp_chunk_lookup_strreset_param(
return NULL;
}
static void sctp_update_strreset_result(struct sctp_association *asoc,
__u32 result)
{
asoc->strreset_result[1] = asoc->strreset_result[0];
asoc->strreset_result[0] = result;
}
struct sctp_chunk *sctp_process_strreset_outreq(
struct sctp_association *asoc,
union sctp_params param,
@ -360,15 +367,19 @@ struct sctp_chunk *sctp_process_strreset_outreq(
if (ntohl(outreq->send_reset_at_tsn) >
sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map)) {
result = SCTP_STRRESET_IN_PROGRESS;
goto out;
goto err;
}
if (request_seq > asoc->strreset_inseq) {
if (TSN_lt(asoc->strreset_inseq, request_seq) ||
TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
result = SCTP_STRRESET_ERR_BAD_SEQNO;
goto out;
} else if (request_seq == asoc->strreset_inseq) {
asoc->strreset_inseq++;
goto err;
} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
i = asoc->strreset_inseq - request_seq - 1;
result = asoc->strreset_result[i];
goto err;
}
asoc->strreset_inseq++;
/* Check strreset_enable after inseq inc, as sender cannot tell
* the peer doesn't enable strreset after receiving response with
@ -427,6 +438,8 @@ struct sctp_chunk *sctp_process_strreset_outreq(
GFP_ATOMIC);
out:
sctp_update_strreset_result(asoc, result);
err:
return sctp_make_strreset_resp(asoc, result, request_seq);
}
@ -443,12 +456,18 @@ struct sctp_chunk *sctp_process_strreset_inreq(
__u32 request_seq;
request_seq = ntohl(inreq->request_seq);
if (request_seq > asoc->strreset_inseq) {
if (TSN_lt(asoc->strreset_inseq, request_seq) ||
TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
result = SCTP_STRRESET_ERR_BAD_SEQNO;
goto out;
} else if (request_seq == asoc->strreset_inseq) {
asoc->strreset_inseq++;
goto err;
} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
i = asoc->strreset_inseq - request_seq - 1;
result = asoc->strreset_result[i];
if (result == SCTP_STRRESET_PERFORMED)
return NULL;
goto err;
}
asoc->strreset_inseq++;
if (!(asoc->strreset_enable & SCTP_ENABLE_RESET_STREAM_REQ))
goto out;
@ -483,10 +502,14 @@ struct sctp_chunk *sctp_process_strreset_inreq(
asoc->strreset_outstanding = 1;
sctp_chunk_hold(asoc->strreset_chunk);
result = SCTP_STRRESET_PERFORMED;
*evp = sctp_ulpevent_make_stream_reset_event(asoc,
SCTP_STREAM_RESET_INCOMING_SSN, nums, str_p, GFP_ATOMIC);
out:
sctp_update_strreset_result(asoc, result);
err:
if (!chunk)
chunk = sctp_make_strreset_resp(asoc, result, request_seq);
@ -506,12 +529,21 @@ struct sctp_chunk *sctp_process_strreset_tsnreq(
__u16 i;
request_seq = ntohl(tsnreq->request_seq);
if (request_seq > asoc->strreset_inseq) {
if (TSN_lt(asoc->strreset_inseq, request_seq) ||
TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
result = SCTP_STRRESET_ERR_BAD_SEQNO;
goto out;
} else if (request_seq == asoc->strreset_inseq) {
asoc->strreset_inseq++;
goto err;
} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
i = asoc->strreset_inseq - request_seq - 1;
result = asoc->strreset_result[i];
if (result == SCTP_STRRESET_PERFORMED) {
next_tsn = asoc->next_tsn;
init_tsn =
sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + 1;
}
goto err;
}
asoc->strreset_inseq++;
if (!(asoc->strreset_enable & SCTP_ENABLE_RESET_ASSOC_REQ))
goto out;
@ -568,6 +600,8 @@ struct sctp_chunk *sctp_process_strreset_tsnreq(
next_tsn, GFP_ATOMIC);
out:
sctp_update_strreset_result(asoc, result);
err:
return sctp_make_strreset_tsnresp(asoc, result, request_seq,
next_tsn, init_tsn);
}
@ -582,15 +616,19 @@ struct sctp_chunk *sctp_process_strreset_addstrm_out(
__u32 result = SCTP_STRRESET_DENIED;
struct sctp_stream_in *streamin;
__u32 request_seq, incnt;
__u16 in;
__u16 in, i;
request_seq = ntohl(addstrm->request_seq);
if (request_seq > asoc->strreset_inseq) {
if (TSN_lt(asoc->strreset_inseq, request_seq) ||
TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
result = SCTP_STRRESET_ERR_BAD_SEQNO;
goto out;
} else if (request_seq == asoc->strreset_inseq) {
asoc->strreset_inseq++;
goto err;
} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
i = asoc->strreset_inseq - request_seq - 1;
result = asoc->strreset_result[i];
goto err;
}
asoc->strreset_inseq++;
if (!(asoc->strreset_enable & SCTP_ENABLE_CHANGE_ASSOC_REQ))
goto out;
@ -638,6 +676,8 @@ struct sctp_chunk *sctp_process_strreset_addstrm_out(
0, ntohs(addstrm->number_of_streams), 0, GFP_ATOMIC);
out:
sctp_update_strreset_result(asoc, result);
err:
return sctp_make_strreset_resp(asoc, result, request_seq);
}
@ -652,15 +692,21 @@ struct sctp_chunk *sctp_process_strreset_addstrm_in(
struct sctp_stream_out *streamout;
struct sctp_chunk *chunk = NULL;
__u32 request_seq, outcnt;
__u16 out;
__u16 out, i;
request_seq = ntohl(addstrm->request_seq);
if (request_seq > asoc->strreset_inseq) {
if (TSN_lt(asoc->strreset_inseq, request_seq) ||
TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
result = SCTP_STRRESET_ERR_BAD_SEQNO;
goto out;
} else if (request_seq == asoc->strreset_inseq) {
asoc->strreset_inseq++;
goto err;
} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
i = asoc->strreset_inseq - request_seq - 1;
result = asoc->strreset_result[i];
if (result == SCTP_STRRESET_PERFORMED)
return NULL;
goto err;
}
asoc->strreset_inseq++;
if (!(asoc->strreset_enable & SCTP_ENABLE_CHANGE_ASSOC_REQ))
goto out;
@ -693,10 +739,14 @@ struct sctp_chunk *sctp_process_strreset_addstrm_in(
stream->outcnt = outcnt;
result = SCTP_STRRESET_PERFORMED;
*evp = sctp_ulpevent_make_stream_change_event(asoc,
0, 0, ntohs(addstrm->number_of_streams), GFP_ATOMIC);
out:
sctp_update_strreset_result(asoc, result);
err:
if (!chunk)
chunk = sctp_make_strreset_resp(asoc, result, request_seq);