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Date: Thu, 14 Dec 2017 16:26:02 -0200
From: Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
To: Xin Long <lucien.xin@...il.com>
Cc: network dev <netdev@...r.kernel.org>, linux-sctp@...r.kernel.org,
Neil Horman <nhorman@...driver.com>, davem@...emloft.net
Subject: Re: [PATCHv2 net-next 3/8] sctp: implement validate_ftsn for
sctp_stream_interleave
On Fri, Dec 15, 2017 at 12:41:27AM +0800, Xin Long wrote:
> 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 <lucien.xin@...il.com>
Acked-by: Marcelo R. Leitner <marcelo.leitner@...il.com>
> ---
> 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 66267db..0db15b5 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 b7720d6..8ac4d5c 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 c609c54..541f347 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 8c9bb41..691d9dc 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 2ead372..cc4a5e3 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)
> --
> 2.1.0
>
> --
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