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 <lucien.xin@gmail.com>
Acked-by: Marcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/sctp/stream_interleave.h b/include/net/sctp/stream_interleave.h
index 66267db..0db15b5 100644 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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)