From 0fc2ea922c8ad5520c80f03facbf396c81dce802 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Fri, 15 Dec 2017 00:41:27 +0800 Subject: sctp: implement validate_ftsn for sctp_stream_interleave validate_ftsn is added as a member of sctp_stream_interleave, used to validate ssn/chunk type for fwdtsn or mid (message id)/chunk type for ifwdtsn, called in sctp_sf_eat_fwd_tsn, just as validate_data. If this check fails, an abort packet will be sent, as said in section 2.3.1 of RFC8260. As ifwdtsn and fwdtsn chunks have different length, it also defines ftsn_chunk_len for sctp_stream_interleave to describe the chunk size. Then it replaces all sizeof(struct sctp_fwdtsn_chunk) with sctp_ftsnchk_len. It also adds the process for ifwdtsn in rx path. As Marcelo pointed out, there's no need to add event table for ifwdtsn, but just share prsctp_chunk_event_table with fwdtsn's. It would drop fwdtsn chunk for ifwdtsn and drop ifwdtsn chunk for fwdtsn by calling validate_ftsn in sctp_sf_eat_fwd_tsn. After this patch, the ifwdtsn can be accepted. Note that this patch also removes the sctp.intl_enable check for idata chunks in sctp_chunk_event_lookup, as it will do this check in validate_data later. Signed-off-by: Xin Long Acked-by: Marcelo R. Leitner Signed-off-by: David S. Miller --- net/sctp/stream_interleave.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) (limited to 'net/sctp/stream_interleave.c') diff --git a/net/sctp/stream_interleave.c b/net/sctp/stream_interleave.c index 2ead372e7a76..cc4a5e320145 100644 --- a/net/sctp/stream_interleave.c +++ b/net/sctp/stream_interleave.c @@ -1153,8 +1153,49 @@ static void sctp_generate_iftsn(struct sctp_outq *q, __u32 ctsn) } } +#define _sctp_walk_ifwdtsn(pos, chunk, end) \ + for (pos = chunk->subh.ifwdtsn_hdr->skip; \ + (void *)pos < (void *)chunk->subh.ifwdtsn_hdr->skip + (end); pos++) + +#define sctp_walk_ifwdtsn(pos, ch) \ + _sctp_walk_ifwdtsn((pos), (ch), ntohs((ch)->chunk_hdr->length) - \ + sizeof(struct sctp_ifwdtsn_chunk)) + +static bool sctp_validate_fwdtsn(struct sctp_chunk *chunk) +{ + struct sctp_fwdtsn_skip *skip; + __u16 incnt; + + if (chunk->chunk_hdr->type != SCTP_CID_FWD_TSN) + return false; + + incnt = chunk->asoc->stream.incnt; + sctp_walk_fwdtsn(skip, chunk) + if (ntohs(skip->stream) >= incnt) + return false; + + return true; +} + +static bool sctp_validate_iftsn(struct sctp_chunk *chunk) +{ + struct sctp_ifwdtsn_skip *skip; + __u16 incnt; + + if (chunk->chunk_hdr->type != SCTP_CID_I_FWD_TSN) + return false; + + incnt = chunk->asoc->stream.incnt; + sctp_walk_ifwdtsn(skip, chunk) + if (ntohs(skip->stream) >= incnt) + return false; + + return true; +} + static struct sctp_stream_interleave sctp_stream_interleave_0 = { .data_chunk_len = sizeof(struct sctp_data_chunk), + .ftsn_chunk_len = sizeof(struct sctp_fwdtsn_chunk), /* DATA process functions */ .make_datafrag = sctp_make_datafrag_empty, .assign_number = sctp_chunk_assign_ssn, @@ -1166,10 +1207,12 @@ static struct sctp_stream_interleave sctp_stream_interleave_0 = { .abort_pd = sctp_ulpq_abort_pd, /* FORWARD-TSN process functions */ .generate_ftsn = sctp_generate_fwdtsn, + .validate_ftsn = sctp_validate_fwdtsn, }; static struct sctp_stream_interleave sctp_stream_interleave_1 = { .data_chunk_len = sizeof(struct sctp_idata_chunk), + .ftsn_chunk_len = sizeof(struct sctp_ifwdtsn_chunk), /* I-DATA process functions */ .make_datafrag = sctp_make_idatafrag_empty, .assign_number = sctp_chunk_assign_mid, @@ -1181,6 +1224,7 @@ static struct sctp_stream_interleave sctp_stream_interleave_1 = { .abort_pd = sctp_intl_abort_pd, /* I-FORWARD-TSN process functions */ .generate_ftsn = sctp_generate_iftsn, + .validate_ftsn = sctp_validate_iftsn, }; void sctp_stream_interleave_init(struct sctp_stream *stream) -- cgit v1.2.3