diff options
Diffstat (limited to 'net/sctp/sm_statefuns.c')
| -rw-r--r-- | net/sctp/sm_statefuns.c | 163 |
1 files changed, 130 insertions, 33 deletions
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index 5e7fb0f..caed19d 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -90,6 +90,11 @@ static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands); +static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands); static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, @@ -98,6 +103,7 @@ static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, struct sctp_transport *transport); static sctp_disposition_t sctp_sf_abort_violation( + const struct sctp_endpoint *ep, const struct sctp_association *asoc, void *arg, sctp_cmd_seq_t *commands, @@ -118,6 +124,13 @@ static sctp_disposition_t sctp_sf_violation_ctsn( void *arg, sctp_cmd_seq_t *commands); +static sctp_disposition_t sctp_sf_violation_chunk( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands); + /* 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. @@ -181,16 +194,21 @@ sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep, struct sctp_chunk *chunk = arg; struct sctp_ulpevent *ev; + if (!sctp_vtag_verify_either(chunk, asoc)) + return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + /* RFC 2960 6.10 Bundling * * An endpoint MUST NOT bundle INIT, INIT ACK or * SHUTDOWN COMPLETE with any other chunks. */ if (!chunk->singleton) - return SCTP_DISPOSITION_VIOLATION; + return sctp_sf_violation_chunk(ep, asoc, type, arg, commands); - if (!sctp_vtag_verify_either(chunk, asoc)) - return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); /* RFC 2960 10.2 SCTP-to-ULP * @@ -450,17 +468,17 @@ sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep, if (!sctp_vtag_verify(chunk, asoc)) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); - /* Make sure that the INIT-ACK chunk has a valid length */ - if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) - return sctp_sf_violation_chunklen(ep, asoc, type, arg, - commands); /* 6.10 Bundling * An endpoint MUST NOT bundle INIT, INIT ACK or * SHUTDOWN COMPLETE with any other chunks. */ if (!chunk->singleton) - return SCTP_DISPOSITION_VIOLATION; + return sctp_sf_violation_chunk(ep, asoc, type, arg, commands); + /* Make sure that the INIT-ACK chunk has a valid length */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); /* Grab the INIT header. */ chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; @@ -585,7 +603,7 @@ sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep, * control endpoint, respond with an ABORT. */ if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) - return sctp_sf_ootb(ep, asoc, type, arg, commands); + return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); /* Make sure that the COOKIE_ECHO chunk has a valid length. * In this case, we check that we have enough for at least a @@ -2496,6 +2514,11 @@ sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep, struct sctp_chunk *chunk = (struct sctp_chunk *) arg; struct sctp_chunk *reply; + /* Make sure that the chunk has a valid length */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + /* Since we are not going to really process this INIT, there * is no point in verifying chunk boundries. Just generate * the SHUTDOWN ACK. @@ -2929,7 +2952,7 @@ sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep, * * The return value is the disposition of the chunk. */ -sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, +static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, @@ -3126,14 +3149,14 @@ sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep, ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; do { - /* Break out if chunk length is less then minimal. */ + /* Report violation if the chunk is less then minimal */ if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) - break; - - ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); - if (ch_end > skb_tail_pointer(skb)) - break; + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + /* Now that we know we at least have a chunk header, + * do things that are type appropriate. + */ if (SCTP_CID_SHUTDOWN_ACK == ch->type) ootb_shut_ack = 1; @@ -3145,6 +3168,12 @@ sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep, if (SCTP_CID_ABORT == ch->type) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); + /* Report violation if chunk len overflows */ + ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); + if (ch_end > skb_tail_pointer(skb)) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + ch = (sctp_chunkhdr_t *) ch_end; } while (ch_end < skb_tail_pointer(skb)); @@ -3244,6 +3273,13 @@ sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep, void *arg, sctp_cmd_seq_t *commands) { + struct sctp_chunk *chunk = arg; + + /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + /* Although we do have an association in this case, it corresponds * to a restarted association. So the packet is treated as an OOTB * packet and the state function that handles OOTB SHUTDOWN_ACK is @@ -3658,6 +3694,16 @@ sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep, void *arg, sctp_cmd_seq_t *commands) { + struct sctp_chunk *chunk = arg; + + /* Make sure that the chunk has a valid length. + * Since we don't know the chunk type, we use a general + * chunkhdr structure to make a comparison. + */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk); return SCTP_DISPOSITION_DISCARD; } @@ -3713,6 +3759,13 @@ sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep, void *arg, sctp_cmd_seq_t *commands) { + struct sctp_chunk *chunk = arg; + + /* Make sure that the chunk has a valid length. */ + if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) + return sctp_sf_violation_chunklen(ep, asoc, type, arg, + commands); + return SCTP_DISPOSITION_VIOLATION; } @@ -3720,12 +3773,14 @@ sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep, * Common function to handle a protocol violation. */ static sctp_disposition_t sctp_sf_abort_violation( + const struct sctp_endpoint *ep, const struct sctp_association *asoc, void *arg, sctp_cmd_seq_t *commands, const __u8 *payload, const size_t paylen) { + struct sctp_packet *packet = NULL; struct sctp_chunk *chunk = arg; struct sctp_chunk *abort = NULL; @@ -3734,30 +3789,51 @@ static sctp_disposition_t sctp_sf_abort_violation( if (!abort) goto nomem; - sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); - SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); + if (asoc) { + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); + SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); - if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { - sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, - SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); - sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, - SCTP_ERROR(ECONNREFUSED)); - sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, - SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); + if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); + sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, + SCTP_ERROR(ECONNREFUSED)); + sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, + SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); + } else { + sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, + SCTP_ERROR(ECONNABORTED)); + sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, + SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); + SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); + } } else { - sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, - SCTP_ERROR(ECONNABORTED)); - sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, - SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); - SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); + packet = sctp_ootb_pkt_new(asoc, chunk); + + if (!packet) + goto nomem_pkt; + + if (sctp_test_T_bit(abort)) + packet->vtag = ntohl(chunk->sctp_hdr->vtag); + + abort->skb->sk = ep->base.sk; + + sctp_packet_append_chunk(packet, abort); + + sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, + SCTP_PACKET(packet)); + + SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); } - sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); + sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands); SCTP_INC_STATS(SCTP_MIB_ABORTEDS); return SCTP_DISPOSITION_ABORT; +nomem_pkt: + sctp_chunk_free(abort); nomem: return SCTP_DISPOSITION_NOMEM; } @@ -3790,7 +3866,7 @@ static sctp_disposition_t sctp_sf_violation_chunklen( { char err_str[]="The following chunk had invalid length:"; - return sctp_sf_abort_violation(asoc, arg, commands, err_str, + return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, sizeof(err_str)); } @@ -3809,10 +3885,31 @@ static sctp_disposition_t sctp_sf_violation_ctsn( { char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:"; - return sctp_sf_abort_violation(asoc, arg, commands, err_str, + return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, sizeof(err_str)); } +/* Handle protocol violation of an invalid chunk bundling. For example, + * when we have an association and we recieve bundled INIT-ACK, or + * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" + * statement from the specs. Additinally, there might be an attacker + * on the path and we may not want to continue this communication. + */ +static sctp_disposition_t sctp_sf_violation_chunk( + const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const sctp_subtype_t type, + void *arg, + sctp_cmd_seq_t *commands) +{ + char err_str[]="The following chunk violates protocol:"; + + if (!asoc) + return sctp_sf_violation(ep, asoc, type, arg, commands); + + return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, + sizeof(err_str)); +} /*************************************************************************** * These are the state functions for handling primitive (Section 10) events. ***************************************************************************/ |
