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-rw-r--r--net/sctp/sm_statefuns.c163
-rw-r--r--net/sctp/sm_statetable.c16
2 files changed, 138 insertions, 41 deletions
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 5e7fb0f54b88..caed19d90d06 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.
***************************************************************************/
diff --git a/net/sctp/sm_statetable.c b/net/sctp/sm_statetable.c
index 70a91ece3c49..ddb0ba3974b0 100644
--- a/net/sctp/sm_statetable.c
+++ b/net/sctp/sm_statetable.c
@@ -110,7 +110,7 @@ const sctp_sm_table_entry_t *sctp_sm_lookup_event(sctp_event_t event_type,
/* SCTP_STATE_EMPTY */ \
TYPE_SCTP_FUNC(sctp_sf_ootb), \
/* SCTP_STATE_CLOSED */ \
- TYPE_SCTP_FUNC(sctp_sf_tabort_8_4_8), \
+ TYPE_SCTP_FUNC(sctp_sf_ootb), \
/* SCTP_STATE_COOKIE_WAIT */ \
TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
/* SCTP_STATE_COOKIE_ECHOED */ \
@@ -173,7 +173,7 @@ const sctp_sm_table_entry_t *sctp_sm_lookup_event(sctp_event_t event_type,
/* SCTP_STATE_EMPTY */ \
TYPE_SCTP_FUNC(sctp_sf_ootb), \
/* SCTP_STATE_CLOSED */ \
- TYPE_SCTP_FUNC(sctp_sf_tabort_8_4_8), \
+ TYPE_SCTP_FUNC(sctp_sf_ootb), \
/* SCTP_STATE_COOKIE_WAIT */ \
TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
/* SCTP_STATE_COOKIE_ECHOED */ \
@@ -194,7 +194,7 @@ const sctp_sm_table_entry_t *sctp_sm_lookup_event(sctp_event_t event_type,
/* SCTP_STATE_EMPTY */ \
TYPE_SCTP_FUNC(sctp_sf_ootb), \
/* SCTP_STATE_CLOSED */ \
- TYPE_SCTP_FUNC(sctp_sf_tabort_8_4_8), \
+ TYPE_SCTP_FUNC(sctp_sf_ootb), \
/* SCTP_STATE_COOKIE_WAIT */ \
TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
/* SCTP_STATE_COOKIE_ECHOED */ \
@@ -216,7 +216,7 @@ const sctp_sm_table_entry_t *sctp_sm_lookup_event(sctp_event_t event_type,
/* SCTP_STATE_EMPTY */ \
TYPE_SCTP_FUNC(sctp_sf_ootb), \
/* SCTP_STATE_CLOSED */ \
- TYPE_SCTP_FUNC(sctp_sf_tabort_8_4_8), \
+ TYPE_SCTP_FUNC(sctp_sf_ootb), \
/* SCTP_STATE_COOKIE_WAIT */ \
TYPE_SCTP_FUNC(sctp_sf_violation), \
/* SCTP_STATE_COOKIE_ECHOED */ \
@@ -258,7 +258,7 @@ const sctp_sm_table_entry_t *sctp_sm_lookup_event(sctp_event_t event_type,
/* SCTP_STATE_EMPTY */ \
TYPE_SCTP_FUNC(sctp_sf_ootb), \
/* SCTP_STATE_CLOSED */ \
- TYPE_SCTP_FUNC(sctp_sf_tabort_8_4_8), \
+ TYPE_SCTP_FUNC(sctp_sf_ootb), \
/* SCTP_STATE_COOKIE_WAIT */ \
TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
/* SCTP_STATE_COOKIE_ECHOED */ \
@@ -300,7 +300,7 @@ const sctp_sm_table_entry_t *sctp_sm_lookup_event(sctp_event_t event_type,
/* SCTP_STATE_EMPTY */ \
TYPE_SCTP_FUNC(sctp_sf_ootb), \
/* SCTP_STATE_CLOSED */ \
- TYPE_SCTP_FUNC(sctp_sf_tabort_8_4_8), \
+ TYPE_SCTP_FUNC(sctp_sf_ootb), \
/* SCTP_STATE_COOKIE_WAIT */ \
TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
/* SCTP_STATE_COOKIE_ECHOED */ \
@@ -499,7 +499,7 @@ static const sctp_sm_table_entry_t addip_chunk_event_table[SCTP_NUM_ADDIP_CHUNK_
/* SCTP_STATE_EMPTY */ \
TYPE_SCTP_FUNC(sctp_sf_ootb), \
/* SCTP_STATE_CLOSED */ \
- TYPE_SCTP_FUNC(sctp_sf_tabort_8_4_8), \
+ TYPE_SCTP_FUNC(sctp_sf_ootb), \
/* SCTP_STATE_COOKIE_WAIT */ \
TYPE_SCTP_FUNC(sctp_sf_discard_chunk), \
/* SCTP_STATE_COOKIE_ECHOED */ \
@@ -528,7 +528,7 @@ chunk_event_table_unknown[SCTP_STATE_NUM_STATES] = {
/* SCTP_STATE_EMPTY */
TYPE_SCTP_FUNC(sctp_sf_ootb),
/* SCTP_STATE_CLOSED */
- TYPE_SCTP_FUNC(sctp_sf_tabort_8_4_8),
+ TYPE_SCTP_FUNC(sctp_sf_ootb),
/* SCTP_STATE_COOKIE_WAIT */
TYPE_SCTP_FUNC(sctp_sf_unk_chunk),
/* SCTP_STATE_COOKIE_ECHOED */
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.