diff options
| -rw-r--r-- | include/net/sctp/constants.h | 4 | ||||
| -rw-r--r-- | include/net/sctp/sm.h | 1 | ||||
| -rw-r--r-- | include/net/sctp/structs.h | 8 | ||||
| -rw-r--r-- | net/sctp/associola.c | 10 | ||||
| -rw-r--r-- | net/sctp/endpointola.c | 29 | ||||
| -rw-r--r-- | net/sctp/input.c | 65 | ||||
| -rw-r--r-- | net/sctp/inqueue.c | 19 | ||||
| -rw-r--r-- | net/sctp/sm_statefuns.c | 218 | ||||
| -rw-r--r-- | net/sctp/sm_statetable.c | 33 |
9 files changed, 374 insertions, 13 deletions
diff --git a/include/net/sctp/constants.h b/include/net/sctp/constants.h index 777118f..da8354e 100644 --- a/include/net/sctp/constants.h +++ b/include/net/sctp/constants.h @@ -183,7 +183,9 @@ typedef enum { SCTP_IERROR_NO_DATA, SCTP_IERROR_BAD_STREAM, SCTP_IERROR_BAD_PORTS, - + SCTP_IERROR_AUTH_BAD_HMAC, + SCTP_IERROR_AUTH_BAD_KEYID, + SCTP_IERROR_PROTO_VIOLATION, } sctp_ierror_t; diff --git a/include/net/sctp/sm.h b/include/net/sctp/sm.h index 148cdb4..bf2f5ed 100644 --- a/include/net/sctp/sm.h +++ b/include/net/sctp/sm.h @@ -143,6 +143,7 @@ sctp_state_fn_t sctp_sf_do_asconf_ack; sctp_state_fn_t sctp_sf_do_9_2_reshutack; sctp_state_fn_t sctp_sf_eat_fwd_tsn; sctp_state_fn_t sctp_sf_eat_fwd_tsn_fast; +sctp_state_fn_t sctp_sf_eat_auth; /* Prototypes for primitive event state functions. */ sctp_state_fn_t sctp_sf_do_prm_asoc; diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index 31841c3..47e54f8 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -724,6 +724,13 @@ struct sctp_chunk { */ struct sctp_transport *transport; + /* SCTP-AUTH: For the special case inbound processing of COOKIE-ECHO + * we need save a pointer to the AUTH chunk, since the SCTP-AUTH + * spec violates the principle premis that all chunks are processed + * in order. + */ + struct sk_buff *auth_chunk; + __u8 rtt_in_progress; /* Is this chunk used for RTT calculation? */ __u8 resent; /* Has this chunk ever been retransmitted. */ __u8 has_tsn; /* Does this chunk have a TSN yet? */ @@ -1067,6 +1074,7 @@ void sctp_inq_init(struct sctp_inq *); void sctp_inq_free(struct sctp_inq *); void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet); struct sctp_chunk *sctp_inq_pop(struct sctp_inq *); +struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *); void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t); /* This is the structure we use to hold outbound chunks. You push diff --git a/net/sctp/associola.c b/net/sctp/associola.c index 3bdd8dc..03158e36 100644 --- a/net/sctp/associola.c +++ b/net/sctp/associola.c @@ -1011,6 +1011,16 @@ static void sctp_assoc_bh_rcv(struct work_struct *work) state = asoc->state; subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); + /* SCTP-AUTH, Section 6.3: + * The receiver has a list of chunk types which it expects + * to be received only after an AUTH-chunk. This list has + * been sent to the peer during the association setup. It + * MUST silently discard these chunks if they are not placed + * after an AUTH chunk in the packet. + */ + if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) + continue; + /* Remember where the last DATA chunk came from so we * know where to send the SACK. */ diff --git a/net/sctp/endpointola.c b/net/sctp/endpointola.c index c8d5023..2d2d81e 100644 --- a/net/sctp/endpointola.c +++ b/net/sctp/endpointola.c @@ -400,6 +400,7 @@ static void sctp_endpoint_bh_rcv(struct work_struct *work) sctp_subtype_t subtype; sctp_state_t state; int error = 0; + int first_time = 1; /* is this the first time through the looop */ if (ep->base.dead) return; @@ -411,6 +412,29 @@ static void sctp_endpoint_bh_rcv(struct work_struct *work) while (NULL != (chunk = sctp_inq_pop(inqueue))) { subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); + /* If the first chunk in the packet is AUTH, do special + * processing specified in Section 6.3 of SCTP-AUTH spec + */ + if (first_time && (subtype.chunk == SCTP_CID_AUTH)) { + struct sctp_chunkhdr *next_hdr; + + next_hdr = sctp_inq_peek(inqueue); + if (!next_hdr) + goto normal; + + /* If the next chunk is COOKIE-ECHO, skip the AUTH + * chunk while saving a pointer to it so we can do + * Authentication later (during cookie-echo + * processing). + */ + if (next_hdr->type == SCTP_CID_COOKIE_ECHO) { + chunk->auth_chunk = skb_clone(chunk->skb, + GFP_ATOMIC); + chunk->auth = 1; + continue; + } + } +normal: /* We might have grown an association since last we * looked, so try again. * @@ -426,6 +450,8 @@ static void sctp_endpoint_bh_rcv(struct work_struct *work) } state = asoc ? asoc->state : SCTP_STATE_CLOSED; + if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) + continue; /* Remember where the last DATA chunk came from so we * know where to send the SACK. @@ -449,5 +475,8 @@ static void sctp_endpoint_bh_rcv(struct work_struct *work) */ if (!sctp_sk(sk)->ep) break; + + if (first_time) + first_time = 0; } } diff --git a/net/sctp/input.c b/net/sctp/input.c index f9a0c92..86503e7 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -911,15 +911,6 @@ static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb, ch = (sctp_chunkhdr_t *) skb->data; - /* If this is INIT/INIT-ACK look inside the chunk too. */ - switch (ch->type) { - case SCTP_CID_INIT: - case SCTP_CID_INIT_ACK: - break; - default: - return NULL; - } - /* The code below will attempt to walk the chunk and extract * parameter information. Before we do that, we need to verify * that the chunk length doesn't cause overflow. Otherwise, we'll @@ -964,6 +955,60 @@ static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb, return NULL; } +/* SCTP-AUTH, Section 6.3: +* If the receiver does not find a STCB for a packet containing an AUTH +* chunk as the first chunk and not a COOKIE-ECHO chunk as the second +* chunk, it MUST use the chunks after the AUTH chunk to look up an existing +* association. +* +* This means that any chunks that can help us identify the association need +* to be looked at to find this assocation. +* +* TODO: The only chunk currently defined that can do that is ASCONF, but we +* don't support that functionality yet. +*/ +static struct sctp_association *__sctp_rcv_auth_lookup(struct sk_buff *skb, + const union sctp_addr *paddr, + const union sctp_addr *laddr, + struct sctp_transport **transportp) +{ + /* XXX - walk through the chunks looking for something that can + * help us find the association. INIT, and INIT-ACK are not permitted. + * That leaves ASCONF, but we don't support that yet. + */ + return NULL; +} + +/* + * There are circumstances when we need to look inside the SCTP packet + * for information to help us find the association. Examples + * include looking inside of INIT/INIT-ACK chunks or after the AUTH + * chunks. + */ +static struct sctp_association *__sctp_rcv_lookup_harder(struct sk_buff *skb, + const union sctp_addr *paddr, + const union sctp_addr *laddr, + struct sctp_transport **transportp) +{ + sctp_chunkhdr_t *ch; + + ch = (sctp_chunkhdr_t *) skb->data; + + /* If this is INIT/INIT-ACK look inside the chunk too. */ + switch (ch->type) { + case SCTP_CID_INIT: + case SCTP_CID_INIT_ACK: + return __sctp_rcv_init_lookup(skb, laddr, transportp); + break; + + case SCTP_CID_AUTH: + return __sctp_rcv_auth_lookup(skb, paddr, laddr, transportp); + break; + } + + return NULL; +} + /* Lookup an association for an inbound skb. */ static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, const union sctp_addr *paddr, @@ -979,7 +1024,7 @@ static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, * parameters within the INIT or INIT-ACK. */ if (!asoc) - asoc = __sctp_rcv_init_lookup(skb, laddr, transportp); + asoc = __sctp_rcv_lookup_harder(skb, paddr, laddr, transportp); return asoc; } diff --git a/net/sctp/inqueue.c b/net/sctp/inqueue.c index e4ea7fd..f10fe7f 100644 --- a/net/sctp/inqueue.c +++ b/net/sctp/inqueue.c @@ -100,6 +100,25 @@ void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *chunk) q->immediate.func(&q->immediate); } +/* Peek at the next chunk on the inqeue. */ +struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *queue) +{ + struct sctp_chunk *chunk; + sctp_chunkhdr_t *ch = NULL; + + chunk = queue->in_progress; + /* If there is no more chunks in this packet, say so */ + if (chunk->singleton || + chunk->end_of_packet || + chunk->pdiscard) + return NULL; + + ch = (sctp_chunkhdr_t *)chunk->chunk_end; + + return ch; +} + + /* Extract a chunk from an SCTP inqueue. * * WARNING: If you need to put the chunk on another queue, you need to diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index 3854863..5aef4aa 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -138,6 +138,11 @@ static sctp_disposition_t sctp_sf_violation_chunk( void *arg, sctp_cmd_seq_t *commands); +static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + struct sctp_chunk *chunk); + /* Small helper function that checks if the chunk length * is of the appropriate length. The 'required_length' argument * is set to be the size of a specific chunk we are testing. @@ -495,8 +500,6 @@ sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep, (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, &err_chunk)) { - SCTP_INC_STATS(SCTP_MIB_ABORTEDS); - /* This chunk contains fatal error. It is to be discarded. * Send an ABORT, with causes if there is any. */ @@ -521,6 +524,22 @@ sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep, sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); error = SCTP_ERROR_INV_PARAM; } + + /* SCTP-AUTH, Section 6.3: + * It should be noted that if the receiver wants to tear + * down an association in an authenticated way only, the + * handling of malformed packets should not result in + * tearing down the association. + * + * This means that if we only want to abort associations + * in an authenticated way (i.e AUTH+ABORT), then we + * can't destory this association just becuase the packet + * was malformed. + */ + if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + + SCTP_INC_STATS(SCTP_MIB_ABORTEDS); return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, asoc, chunk->transport); } @@ -699,6 +718,36 @@ sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep, if (error) goto nomem_init; + /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo + * is supposed to be authenticated and we have to do delayed + * authentication. We've just recreated the association using + * the information in the cookie and now it's much easier to + * do the authentication. + */ + if (chunk->auth_chunk) { + struct sctp_chunk auth; + sctp_ierror_t ret; + + /* set-up our fake chunk so that we can process it */ + auth.skb = chunk->auth_chunk; + auth.asoc = chunk->asoc; + auth.sctp_hdr = chunk->sctp_hdr; + auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk, + sizeof(sctp_chunkhdr_t)); + skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t)); + auth.transport = chunk->transport; + + ret = sctp_sf_authenticate(ep, new_asoc, type, &auth); + + /* We can now safely free the auth_chunk clone */ + kfree_skb(chunk->auth_chunk); + + if (ret != SCTP_IERROR_NO_ERROR) { + sctp_association_free(new_asoc); + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + } + } + repl = sctp_make_cookie_ack(new_asoc, chunk); if (!repl) goto nomem_init; @@ -3653,6 +3702,156 @@ gen_shutdown: } /* + * SCTP-AUTH Section 6.3 Receving authenticated chukns + * + * The receiver MUST use the HMAC algorithm indicated in the HMAC + * Identifier field. If this algorithm was not specified by the + * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk + * during association setup, the AUTH chunk and all chunks after it MUST + * be discarded and an ERROR chunk SHOULD be sent with the error cause + * defined in Section 4.1. + * + * If an endpoint with no shared key receives a Shared Key Identifier + * other than 0, it MUST silently discard all authenticated chunks. If + * the endpoint has at least one endpoint pair shared key for the peer, + * it MUST use the key specified by the Shared Key Identifier if a + * key has been configured for that Shared Key Identifier. If no + * endpoint pair shared key has been configured for that Shared Key + * Identifier, all authenticated chunks MUST be silently discarded. + * + * Verification Tag: 8.5 Verification Tag [Normal verification] + * + * The return value is the disposition of the chunk. + */ +static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + struct sctp_chunk *chunk) +{ + struct sctp_authhdr *auth_hdr; + struct sctp_hmac *hmac; + unsigned int sig_len; + __u16 key_id; + __u8 *save_digest; + __u8 *digest; + + /* Pull in the auth header, so we can do some more verification */ + auth_hdr = (struct sctp_authhdr *)chunk->skb->data; + chunk->subh.auth_hdr = auth_hdr; + skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); + + /* Make sure that we suport the HMAC algorithm from the auth + * chunk. + */ + if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) + return SCTP_IERROR_AUTH_BAD_HMAC; + + /* Make sure that the provided shared key identifier has been + * configured + */ + key_id = ntohs(auth_hdr->shkey_id); + if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) + return SCTP_IERROR_AUTH_BAD_KEYID; + + + /* Make sure that the length of the signature matches what + * we expect. + */ + sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); + hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); + if (sig_len != hmac->hmac_len) + return SCTP_IERROR_PROTO_VIOLATION; + + /* Now that we've done validation checks, we can compute and + * verify the hmac. The steps involved are: + * 1. Save the digest from the chunk. + * 2. Zero out the digest in the chunk. + * 3. Compute the new digest + * 4. Compare saved and new digests. + */ + digest = auth_hdr->hmac; + skb_pull(chunk->skb, sig_len); + + save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); + if (!save_digest) + goto nomem; + + memset(digest, 0, sig_len); + + sctp_auth_calculate_hmac(asoc, chunk->skb, + (struct sctp_auth_chunk *)chunk->chunk_hdr, + GFP_ATOMIC); + + /* Discard the packet if the digests do not match */ + if (memcmp(save_digest, digest, sig_len)) { + kfree(save_digest); + return SCTP_IERROR_BAD_SIG; + } + + kfree(save_digest); + chunk->auth = 1; + + return SCTP_IERROR_NO_ERROR; +nomem: + return SCTP_IERROR_NOMEM; +} + +sctp_disposition_t sctp_sf_eat_auth(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + struct sctp_authhdr *auth_hdr; + struct sctp_chunk *chunk = arg; + struct sctp_chunk *err_chunk; + sctp_ierror_t error; + + if (!sctp_vtag_verify(chunk, asoc)) { + sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, + SCTP_NULL()); + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + } + + /* Make sure that the AUTH chunk has valid length. */ + if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + + auth_hdr = (struct sctp_authhdr *)chunk->skb->data; + error = sctp_sf_authenticate(ep, asoc, type, chunk); + switch (error) { + case SCTP_IERROR_AUTH_BAD_HMAC: + /* Generate the ERROR chunk and discard the rest + * of the packet + */ + err_chunk = sctp_make_op_error(asoc, chunk, + SCTP_ERROR_UNSUP_HMAC, + &auth_hdr->hmac_id, + sizeof(__u16)); + if (err_chunk) { + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, + SCTP_CHUNK(err_chunk)); + } + /* Fall Through */ + case SCTP_IERROR_AUTH_BAD_KEYID: + case SCTP_IERROR_BAD_SIG: + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + break; + case SCTP_IERROR_PROTO_VIOLATION: + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + break; + case SCTP_IERROR_NOMEM: + return SCTP_DISPOSITION_NOMEM; + default: + break; + } + + return SCTP_DISPOSITION_CONSUME; +} + +/* * Process an unknown chunk. * * Section: 3.2. Also, 2.1 in the implementor's guide. @@ -3857,6 +4056,20 @@ static sctp_disposition_t sctp_sf_abort_violation( if (!abort) goto nomem; + /* SCTP-AUTH, Section 6.3: + * It should be noted that if the receiver wants to tear + * down an association in an authenticated way only, the + * handling of malformed packets should not result in + * tearing down the association. + * + * This means that if we only want to abort associations + * in an authenticated way (i.e AUTH+ABORT), then we + * can't destory this association just becuase the packet + * was malformed. + */ + if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) + goto discard; + if (asoc) { sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); @@ -3894,6 +4107,7 @@ static sctp_disposition_t sctp_sf_abort_violation( SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); } +discard: sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands); SCTP_INC_STATS(SCTP_MIB_ABORTEDS); diff --git a/net/sctp/sm_statetable.c b/net/sctp/sm_statetable.c index ddb0ba3..a93a4bc 100644 --- a/net/sctp/sm_statetable.c +++ b/net/sctp/sm_statetable.c @@ -523,6 +523,34 @@ static const sctp_sm_table_entry_t prsctp_chunk_event_table[SCTP_NUM_PRSCTP_CHUN TYPE_SCTP_FWD_TSN, }; /*state_fn_t prsctp_chunk_event_table[][] */ +#define TYPE_SCTP_AUTH { \ + /* SCTP_STATE_EMPTY */ \ + TYPE_SCTP_FUNC(sctp_sf_ootb), \ + /* SCTP_STATE_CLOSED */ \ + TYPE_SCTP_FUNC(sctp_sf_ootb), \ + /* SCTP_STATE_COOKIE_WAIT */ \ + TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \ + /* SCTP_STATE_COOKIE_ECHOED */ \ + TYPE_SCTP_FUNC(sctp_sf_eat_auth), \ + /* SCTP_STATE_ESTABLISHED */ \ + TYPE_SCTP_FUNC(sctp_sf_eat_auth), \ + /* SCTP_STATE_SHUTDOWN_PENDING */ \ + TYPE_SCTP_FUNC(sctp_sf_eat_auth), \ + /* SCTP_STATE_SHUTDOWN_SENT */ \ + TYPE_SCTP_FUNC(sctp_sf_eat_auth), \ + /* SCTP_STATE_SHUTDOWN_RECEIVED */ \ + TYPE_SCTP_FUNC(sctp_sf_eat_auth), \ + /* SCTP_STATE_SHUTDOWN_ACK_SENT */ \ + TYPE_SCTP_FUNC(sctp_sf_eat_auth), \ +} /* TYPE_SCTP_AUTH */ + +/* The primary index for this table is the chunk type. + * The secondary index for this table is the state. + */ +static const sctp_sm_table_entry_t auth_chunk_event_table[SCTP_NUM_AUTH_CHUNK_TYPES][SCTP_STATE_NUM_STATES] = { + TYPE_SCTP_AUTH, +}; /*state_fn_t auth_chunk_event_table[][] */ + static const sctp_sm_table_entry_t chunk_event_table_unknown[SCTP_STATE_NUM_STATES] = { /* SCTP_STATE_EMPTY */ @@ -976,5 +1004,10 @@ static const sctp_sm_table_entry_t *sctp_chunk_event_lookup(sctp_cid_t cid, return &addip_chunk_event_table[1][state]; } + if (sctp_auth_enable) { + if (cid == SCTP_CID_AUTH) + return &auth_chunk_event_table[0][state]; + } + return &chunk_event_table_unknown[state]; } |
