From 0fc2ea922c8ad5520c80f03facbf396c81dce802 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Fri, 15 Dec 2017 00:41:27 +0800 Subject: [PATCH] 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 --- include/net/sctp/stream_interleave.h | 2 ++ include/net/sctp/structs.h | 10 +++++++ net/sctp/sm_statefuns.c | 24 +++++---------- net/sctp/sm_statetable.c | 4 +-- net/sctp/stream_interleave.c | 44 ++++++++++++++++++++++++++++ 5 files changed, 66 insertions(+), 18 deletions(-) diff --git a/include/net/sctp/stream_interleave.h b/include/net/sctp/stream_interleave.h index 66267dbcecba..0db15b50c5e6 100644 --- a/include/net/sctp/stream_interleave.h +++ b/include/net/sctp/stream_interleave.h @@ -33,6 +33,7 @@ struct sctp_stream_interleave { __u16 data_chunk_len; + __u16 ftsn_chunk_len; /* (I-)DATA process */ struct sctp_chunk *(*make_datafrag)(const struct sctp_association *asoc, const struct sctp_sndrcvinfo *sinfo, @@ -49,6 +50,7 @@ struct sctp_stream_interleave { void (*abort_pd)(struct sctp_ulpq *ulpq, gfp_t gfp); /* (I-)FORWARD-TSN process */ void (*generate_ftsn)(struct sctp_outq *q, __u32 ctsn); + bool (*validate_ftsn)(struct sctp_chunk *chunk); }; void sctp_stream_interleave_init(struct sctp_stream *stream); diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index b7720d65a975..8ac4d5cdbfed 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -1443,6 +1443,16 @@ static inline __u16 sctp_datahdr_len(const struct sctp_stream *stream) return stream->si->data_chunk_len - sizeof(struct sctp_chunkhdr); } +static inline __u16 sctp_ftsnchk_len(const struct sctp_stream *stream) +{ + return stream->si->ftsn_chunk_len; +} + +static inline __u16 sctp_ftsnhdr_len(const struct sctp_stream *stream) +{ + return stream->si->ftsn_chunk_len - sizeof(struct sctp_chunkhdr); +} + /* SCTP_GET_ASSOC_STATS counters */ struct sctp_priv_assoc_stats { /* Maximum observed rto in the association during subsequent diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index c609c5409910..541f34735346 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -3957,7 +3957,6 @@ enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, { struct sctp_fwdtsn_hdr *fwdtsn_hdr; struct sctp_chunk *chunk = arg; - struct sctp_fwdtsn_skip *skip; __u16 len; __u32 tsn; @@ -3971,7 +3970,7 @@ enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); /* Make sure that the FORWARD_TSN chunk has valid length. */ - if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) + if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands); @@ -3990,14 +3989,11 @@ enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) goto discard_noforce; - /* Silently discard the chunk if stream-id is not valid */ - sctp_walk_fwdtsn(skip, chunk) { - if (ntohs(skip->stream) >= asoc->stream.incnt) - goto discard_noforce; - } + if (!asoc->stream.si->validate_ftsn(chunk)) + goto discard_noforce; sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); - if (len > sizeof(struct sctp_fwdtsn_hdr)) + if (len > sctp_ftsnhdr_len(&asoc->stream)) sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, SCTP_CHUNK(chunk)); @@ -4028,7 +4024,6 @@ enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( { struct sctp_fwdtsn_hdr *fwdtsn_hdr; struct sctp_chunk *chunk = arg; - struct sctp_fwdtsn_skip *skip; __u16 len; __u32 tsn; @@ -4042,7 +4037,7 @@ enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); /* Make sure that the FORWARD_TSN chunk has a valid length. */ - if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) + if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands); @@ -4061,14 +4056,11 @@ enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) goto gen_shutdown; - /* Silently discard the chunk if stream-id is not valid */ - sctp_walk_fwdtsn(skip, chunk) { - if (ntohs(skip->stream) >= asoc->stream.incnt) - goto gen_shutdown; - } + if (!asoc->stream.si->validate_ftsn(chunk)) + goto gen_shutdown; sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); - if (len > sizeof(struct sctp_fwdtsn_hdr)) + if (len > sctp_ftsnhdr_len(&asoc->stream)) sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, SCTP_CHUNK(chunk)); diff --git a/net/sctp/sm_statetable.c b/net/sctp/sm_statetable.c index 8c9bb4109f47..691d9dc620e3 100644 --- a/net/sctp/sm_statetable.c +++ b/net/sctp/sm_statetable.c @@ -985,14 +985,14 @@ static const struct sctp_sm_table_entry *sctp_chunk_event_lookup( if (state > SCTP_STATE_MAX) return &bug; - if (net->sctp.intl_enable && cid == SCTP_CID_I_DATA) + if (cid == SCTP_CID_I_DATA) cid = SCTP_CID_DATA; if (cid <= SCTP_CID_BASE_MAX) return &chunk_event_table[cid][state]; if (net->sctp.prsctp_enable) { - if (cid == SCTP_CID_FWD_TSN) + if (cid == SCTP_CID_FWD_TSN || cid == SCTP_CID_I_FWD_TSN) return &prsctp_chunk_event_table[0][state]; } 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) -- GitLab