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libwebsockets/lib/secure-streams/serialized/proxy/proxy-deserialize.c
Andy Green 2cfa260e62 sspc: refactor to allow different transports 
This is a NOP for existing usecases.

At the moment the only implemented transport for serialized SS is wsi, it's
typically used with Unix Domain Sockets, but it also works over tcp the
same.

It generalizes the interface between serialized chunks and the
transport, separately for client and proxy.  The wsi transport is migrated
to use the new transport ops structs.

It will then be possible to "bring your own transport", so long as it is
reliable, and in-order, both for proxy and client / sspc.

We also adapt minimal-secure-streams-binance to build the -client variant
via SS proxy as well.

LWS_ONLY_SSPC is added so libwebsockets can be produced with just sspc
client support even for tiny targets.

A new embedded minimal example for rpi pico is also provided that
demonstrates using Serialized SS over a UART to an SS proxy, to implement
the SS Binance example on the pico, even though it has no networking itself.
2021-10-08 09:48:41 +01:00

841 lines
19 KiB
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/*
* libwebsockets - small server side websockets and web server implementation
*
* Copyright (C) 2019 - 2021 Andy Green <andy@warmcat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
*
* Serialized Secure Streams deserializer for Proxy side
*/
#include <private-lib-core.h>
/*
* event loop is consuming dsh-buffered, already-serialized tx from the
* foreign side
*/
int
lws_ss_deserialize_tx_payload(struct lws_dsh *dsh, struct lws *wsi,
lws_ss_tx_ordinal_t ord, uint8_t *buf,
size_t *len, int *flags)
{
uint8_t *p;
size_t si;
if (lws_dsh_get_head(dsh, KIND_C_TO_P, (void **)&p, &si)) {
*len = 0;
return 0;
}
/*
* The packet in the dsh has a proxying serialization header, process
* and strip it so we just forward the payload
*/
if (*len <= si - 23 || si < 23) {
/*
* What comes out of the dsh needs to fit in the tx buffer...
* we have arrangements at the proxy rx of the client UDS to
* chop chunks larger than 1380 into seuqential lumps of 1380
*/
lwsl_err("%s: *len = %d, si = %d\n", __func__, (int)*len, (int)si);
assert(0);
return 1;
}
if (p[0] != LWSSS_SER_TXPRE_TX_PAYLOAD) {
assert(0);
return 1;
}
*len = (size_t)(lws_ser_ru16be(&p[1]) - (23 - 3));
if (*len != si - 23) {
/*
* We cannot accept any length that doesn't reflect the actual
* length of what came in from the dsh, either something nasty
* happened with truncation or we are being attacked
*/
assert(0);
return 1;
}
memcpy(buf, p + 23, si - 23);
*flags = (int)lws_ser_ru32be(&p[3]);
lws_dsh_free((void **)&p);
return 0;
}
/*
* event loop side is consuming serialized data from the client via dsh, parse
* it using a bytewise parser for the serialization header(s)...
* it's possibly coalesced
*
* client: pss is pointing to the start of userdata. We can use
* pss_to_sspc_h(_pss, _ssi) to convert that to a pointer to the sspc
* handle
*
* proxy: pss is pointing to &conn->ss, a pointer to the ss handle
*
* Returns one of
*
* LWSSSSRET_OK
* LWSSSSRET_DISCONNECT_ME
* LWSSSSRET_DESTROY_ME
*/
/* convert userdata ptr _pss to handle pointer, allowing for any layout in
* userdata */
#define client_pss_to_sspc_h(_pss, _ssi) (*((lws_sspc_handle_t **) \
((uint8_t *)_pss) + _ssi->handle_offset))
/* client pss to sspc userdata */
#define client_pss_to_userdata(_pss) ((void *)_pss)
/* proxy convert pss to ss handle */
#define proxy_pss_to_ss_h(_pss) (*_pss)
/* convert userdata ptr _pss to handle pointer, allowing for any layout in
* userdata */
#define client_pss_to_sspc_h(_pss, _ssi) (*((lws_sspc_handle_t **) \
((uint8_t *)_pss) + _ssi->handle_offset))
/* client pss to sspc userdata */
#define client_pss_to_userdata(_pss) ((void *)_pss)
/* proxy convert pss to ss handle */
#define proxy_pss_to_ss_h(_pss) (*_pss)
int
lws_ss_proxy_deserialize_parse(struct lws_ss_serialization_parser *par,
struct lws_context *context,
struct lws_dsh *dsh, const uint8_t *cp,
size_t len, lws_ss_conn_states_t *state,
void *parconn, lws_ss_handle_t **pss,
lws_ss_info_t *ssi)
{
lws_ss_state_return_t r;
lws_ss_metadata_t *pm;
uint8_t pre[23];
uint32_t flags;
lws_usec_t us;
uint8_t *p;
int n;
while (len--) {
switch (par->ps) {
case RPAR_TYPE:
par->type = *cp++;
par->ps++;
break;
case RPAR_LEN_MSB: /* this is remaining frame length */
par->rem = (uint16_t)((*cp++) << 8);
par->ps++;
break;
case RPAR_LEN_LSB:
par->rem = (uint16_t)(par->rem | *cp++);
switch (par->type) {
/* event loop side */
case LWSSS_SER_TXPRE_TX_PAYLOAD:
if (*state != LPCSPROX_OPERATIONAL)
goto hangup;
par->ps = RPAR_FLAG_B3;
break;
case LWSSS_SER_TXPRE_DESTROYING:
par->ps = RPAR_TYPE;
lwsl_cx_notice(context, "DESTROYING");
goto hangup;
case LWSSS_SER_TXPRE_ONWARD_CONNECT:
if (*state != LPCSPROX_OPERATIONAL)
goto hangup;
par->ps = RPAR_TYPE;
lwsl_cx_notice(context, "ONWARD_CONNECT");
/*
* Shrug it off if we are already connecting or
* connected
*/
if (!proxy_pss_to_ss_h(pss) ||
proxy_pss_to_ss_h(pss)->wsi)
break;
/*
* We're going to try to do the onward connect
*/
if ((proxy_pss_to_ss_h(pss) &&
lws_fi(&proxy_pss_to_ss_h(pss)->fic,
"ssproxy_onward_conn_fail")) ||
_lws_ss_client_connect(proxy_pss_to_ss_h(pss),
0, parconn) ==
LWSSSSRET_DESTROY_ME)
goto hangup;
break;
case LWSSS_SER_TXPRE_STREAMTYPE:
if (*state != LPCSPROX_WAIT_INITIAL_TX)
goto hangup;
if (par->rem < 1 + 4 + 1)
goto hangup;
par->ps = RPAR_INIT_PROVERS;
break;
case LWSSS_SER_TXPRE_METADATA:
if (par->rem < 3)
goto hangup;
par->ctr = 0;
par->ps = RPAR_METADATA_NAMELEN;
break;
case LWSSS_SER_TXPRE_TXCR_UPDATE:
par->ps = RPAR_TXCR0;
par->ctr = 0;
break;
case LWSSS_SER_TXPRE_TIMEOUT_UPDATE:
if (par->rem != 4)
goto hangup;
par->ps = RPAR_TIMEOUT0;
par->ctr = 0;
break;
case LWSSS_SER_TXPRE_PAYLOAD_LENGTH_HINT:
if (par->rem != 4)
goto hangup;
par->ps = RPAR_PAYLEN0;
par->ctr = 0;
break;
/* client side */
case LWSSS_SER_RXPRE_RX_PAYLOAD:
case LWSSS_SER_RXPRE_CREATE_RESULT:
case LWSSS_SER_RXPRE_CONNSTATE:
case LWSSS_SER_RXPRE_METADATA:
goto hangup;
case LWSSS_SER_RXPRE_TXCR_UPDATE:
par->ctr = 0;
par->ps = RPAR_RX_TXCR_UPDATE;
break;
case LWSSS_SER_RXPRE_PERF:
par->ctr = 0;
if (!par->rem)
goto hangup;
par->ps = RPAR_PERF;
break;
default:
lwsl_cx_notice(context, "bad type 0x%x",
par->type);
goto hangup;
}
break;
case RPAR_FLAG_B3:
case RPAR_FLAG_B2:
case RPAR_FLAG_B1:
case RPAR_FLAG_B0:
par->flags <<= 8;
par->flags |= *cp++;
par->ps++;
if (!par->rem--)
goto hangup;
break;
case RPAR_LATA3:
case RPAR_LATA2:
case RPAR_LATA1:
case RPAR_LATA0:
par->usd_phandling <<= 8;
par->usd_phandling |= *cp++;
par->ps++;
if (!par->rem--)
goto hangup;
break;
case RPAR_LATB7:
case RPAR_LATB6:
case RPAR_LATB5:
case RPAR_LATB4:
case RPAR_LATB3:
case RPAR_LATB2:
case RPAR_LATB1:
case RPAR_LATB0:
par->ust_pwait <<= 8;
par->ust_pwait |= *cp++;
par->ps++;
par->frag1 = 1;
if (!par->rem--)
goto hangup;
if (par->ps == RPAR_RIDESHARE_LEN &&
!(par->flags & LWSSS_FLAG_RIDESHARE))
par->ps = RPAR_PAYLOAD;
if (par->rem)
break;
/* fallthru - handle 0-length payload */
if (!(par->flags & LWSSS_FLAG_RIDESHARE))
goto payload_ff;
goto hangup;
/*
* Inbound rideshare info is provided on the RX packet
* itself
*/
case RPAR_RIDESHARE_LEN:
par->slen = *cp++;
par->ctr = 0;
par->ps++;
if (par->rem-- < par->slen)
goto hangup;
break;
case RPAR_PERF:
n = (int)len + 1;
if (n > par->rem)
n = par->rem;
if (n) {
cp += n;
par->rem = (uint16_t)(par->rem -
(uint16_t)(unsigned int)n);
len = (len + 1) - (unsigned int)n;
}
if (!par->rem)
par->ps = RPAR_TYPE;
break;
case RPAR_RIDESHARE:
par->rideshare[par->ctr++] = (char)*cp++;
if (!par->rem--)
goto hangup;
if (par->ctr != par->slen)
break;
par->ps = RPAR_PAYLOAD;
if (par->rem)
break;
/* fallthru - handle 0-length payload */
case RPAR_PAYLOAD:
payload_ff:
n = (int)len + 1;
if (n > par->rem)
n = par->rem;
/*
* We get called with a serialized buffer of a size
* chosen by the client. We can only create dsh entries
* with up to 1380 payload, to guarantee we can emit
* them on the onward connection atomically.
*
* If 1380 isn't enough to cover what was handed to us,
* we'll stop at 1380 and go around again and create
* more dsh entries for the rest, with their own
* headers.
*/
if (n > 1380)
n = 1380;
/*
* Since we're in the business of fragmenting client
* serialized payloads at 1380, we have to deal with
* refragmenting the SOM / EOM flags that covered the
* whole client serialized packet, so they apply to
* each dsh entry we split it into correctly
*/
flags = par->flags & LWSSS_FLAG_RELATED_START;
if (par->frag1)
/*
* Only set the first time we came to this
* state after deserialization of the header
*/
flags |= par->flags &
(LWSSS_FLAG_SOM | LWSSS_FLAG_POLL);
if (par->rem == n)
/*
* We are going to complete the advertised
* payload length from the client on this dsh,
* so give him the EOM type flags if any
*/
flags |= par->flags & (LWSSS_FLAG_EOM |
LWSSS_FLAG_RELATED_END);
par->frag1 = 0;
us = lws_now_usecs();
{
lws_ss_handle_t *hss;
/*
* Proxy - we received some serialized tx from
* the client.
*
* The header for buffering private to the
* proxy is 23 bytes vs 19, so we can hold the
* current time when it was buffered
* additionally
*/
hss = proxy_pss_to_ss_h(pss);
if (hss)
lwsl_ss_info(hss, "C2P RX: len %d", (int)n);
p = pre;
pre[0] = LWSSS_SER_TXPRE_TX_PAYLOAD;
lws_ser_wu16be(&p[1], (uint16_t)((unsigned int)n + 23 - 3));
lws_ser_wu32be(&p[3], flags);
/* us held at client before written */
lws_ser_wu32be(&p[7], par->usd_phandling);
/* us taken for transit to proxy */
lws_ser_wu32be(&p[11], (uint32_t)(us -
(lws_usec_t)par->ust_pwait));
/* time used later to find proxy hold time */
lws_ser_wu64be(&p[15], (uint64_t)us);
if ((hss &&
lws_fi(&hss->fic, "ssproxy_dsh_c2p_pay_oom")) ||
lws_dsh_alloc_tail(dsh, KIND_C_TO_P, pre,
23, cp, (unsigned int)n)) {
lwsl_ss_err(hss, "unable to alloc in dsh 3");
return LWSSSSRET_DISCONNECT_ME;
}
lwsl_notice("%s: dsh c2p %d, p2c %d\n", __func__,
(int)lws_dsh_get_size(dsh, KIND_C_TO_P),
(int)lws_dsh_get_size(dsh, 1));
if (hss)
_lws_ss_request_tx(hss);
}
if (n) {
cp += n;
par->rem = (uint16_t)(par->rem -
(uint16_t)(unsigned int)n);
len = (len + 1) - (unsigned int)n;
/*
* if we didn't consume it all, we'll come
* around again and produce more dsh entries up
* to 1380 each until it is gone
*/
}
if (!par->rem)
par->ps = RPAR_TYPE;
break;
case RPAR_RX_TXCR_UPDATE:
goto hangup;
case RPAR_INIT_PROVERS:
/* Protocol version byte for this connection */
par->protocol_version = *cp++;
/*
* So we have to know what versions of the serialization
* protocol we can support at the proxy side, and
* reject anythng we don't know how to deal with
* noisily in the logs.
*/
if (par->protocol_version != 1) {
lwsl_err("%s: Rejecting client with "
"unsupported SSv%d protocol\n",
__func__, par->protocol_version);
goto hangup;
}
if (!--par->rem)
goto hangup;
par->ctr = 0;
par->ps = RPAR_INIT_PID;
break;
case RPAR_INIT_PID:
if (!--par->rem)
goto hangup;
par->temp32 = (par->temp32 << 8) | *cp++;
if (++par->ctr < 4)
break;
par->client_pid = (uint32_t)par->temp32;
par->ctr = 0;
par->ps = RPAR_INITTXC0;
break;
case RPAR_INITTXC0:
if (!--par->rem)
goto hangup;
par->temp32 = (par->temp32 << 8) | *cp++;
if (++par->ctr < 4)
break;
par->txcr_out = par->temp32;
par->ctr = 0;
par->ps = RPAR_STREAMTYPE;
break;
/*
* These are the client adjusting our / the remote peer ability
* to send back to him. He's sending a signed u32 BE
*/
case RPAR_TXCR0:
par->temp32 = (par->temp32 << 8) | *cp++;
if (++par->ctr < 4) {
if (!--par->rem)
goto hangup;
break;
}
if (--par->rem)
goto hangup;
/*
* We're the proxy, being told by the client
* that it wants to allow more tx from the peer
* on the onward connection towards it.
*/
#if defined(LWS_ROLE_H2) || defined(LWS_ROLE_MQTT)
if (proxy_pss_to_ss_h(pss) &&
proxy_pss_to_ss_h(pss)->wsi) {
lws_wsi_tx_credit(
proxy_pss_to_ss_h(pss)->wsi,
LWSTXCR_PEER_TO_US,
par->temp32);
lwsl_notice("%s: proxy RX_PEER_TXCR: +%d (est %d)\n",
__func__, par->temp32,
proxy_pss_to_ss_h(pss)->wsi->
txc.peer_tx_cr_est);
_lws_ss_request_tx(proxy_pss_to_ss_h(pss));
} else
#endif
lwsl_info("%s: dropping TXCR\n", __func__);
par->ps = RPAR_TYPE;
break;
case RPAR_TIMEOUT0:
par->temp32 = (par->temp32 << 8) | *cp++;
if (++par->ctr < 4) {
if (!--par->rem)
goto hangup;
break;
}
if (--par->rem)
goto hangup;
/*
* Proxy...
*
* *pss may have gone away asynchronously inbetweentimes
*/
if (proxy_pss_to_ss_h(pss)) {
if ((unsigned int)par->temp32 == 0xffffffff) {
lwsl_notice("%s: cancel ss timeout\n",
__func__);
lws_ss_cancel_timeout(
proxy_pss_to_ss_h(pss));
} else {
if (!par->temp32)
par->temp32 = (int)
proxy_pss_to_ss_h(pss)->
policy->timeout_ms;
lwsl_notice("%s: set ss timeout for +%ums\n",
__func__, par->temp32);
lws_ss_start_timeout(
proxy_pss_to_ss_h(pss),
(unsigned int)par->temp32);
}
}
par->ps = RPAR_TYPE;
break;
case RPAR_PAYLEN0:
/*
* It's the length from lws_ss_request_tx_len() being
* passed up to the proxy
*/
par->temp32 = (par->temp32 << 8) | *cp++;
if (++par->ctr < 4) {
if (!--par->rem)
goto hangup;
break;
}
if (--par->rem)
goto hangup;
lwsl_notice("%s: set payload len %u\n", __func__,
par->temp32);
par->ps = RPAR_TYPE;
if (proxy_pss_to_ss_h(pss)) {
r = lws_ss_request_tx_len(proxy_pss_to_ss_h(pss),
(unsigned long)par->temp32);
if (r == LWSSSSRET_DESTROY_ME)
goto hangup;
}
break;
case RPAR_METADATA_NAMELEN:
/* both client and proxy */
if (!--par->rem)
goto hangup;
par->slen = *cp++;
if (par->slen >= sizeof(par->metadata_name) - 1)
goto hangup;
par->ctr = 0;
par->ps++;
break;
case RPAR_METADATA_NAME:
/* both client and proxy */
if (!--par->rem)
goto hangup;
par->metadata_name[par->ctr++] = (char)*cp++;
if (par->ctr != par->slen)
break;
par->metadata_name[par->ctr] = '\0';
par->ps = RPAR_METADATA_VALUE;
/* proxy side is receiving it */
if (!proxy_pss_to_ss_h(pss))
goto hangup;
if (!proxy_pss_to_ss_h(pss)->policy) {
lwsl_err("%s: null policy\n", __func__);
goto hangup;
}
/*
* This is the policy's metadata list for the given
* name
*/
pm = lws_ss_policy_metadata(
proxy_pss_to_ss_h(pss)->policy,
par->metadata_name);
if (!pm) {
lwsl_err("%s: metadata %s not in proxy policy\n",
__func__, par->metadata_name);
goto hangup;
}
par->ssmd = lws_ss_get_handle_metadata(
proxy_pss_to_ss_h(pss),
par->metadata_name);
if (par->ssmd) {
if (par->ssmd->value_on_lws_heap)
lws_free_set_NULL(par->ssmd->value__may_own_heap);
par->ssmd->value_on_lws_heap = 0;
if (proxy_pss_to_ss_h(pss) &&
lws_fi(&proxy_pss_to_ss_h(pss)->fic, "ssproxy_rx_metadata_oom"))
par->ssmd->value__may_own_heap = NULL;
else
par->ssmd->value__may_own_heap =
lws_malloc((unsigned int)par->rem + 1, "metadata");
if (!par->ssmd->value__may_own_heap) {
lwsl_err("%s: OOM mdv\n", __func__);
goto hangup;
}
par->ssmd->length = par->rem;
((uint8_t *)par->ssmd->value__may_own_heap)[par->rem] = '\0';
/* mark it as needing cleanup */
par->ssmd->value_on_lws_heap = 1;
}
par->ctr = 0;
break;
case RPAR_METADATA_VALUE:
/* both client and proxy */
((uint8_t *)(par->ssmd->value__may_own_heap))[par->ctr++] = *cp++;
if (--par->rem)
break;
/* we think we got all the value */
lwsl_ss_info(proxy_pss_to_ss_h(pss),
"RPAR_METADATA_VALUE for %s (len %d)",
par->ssmd->name,
(int)par->ssmd->length);
lwsl_hexdump_ss_info(proxy_pss_to_ss_h(pss),
par->ssmd->value__may_own_heap,
par->ssmd->length);
par->ps = RPAR_TYPE;
break;
case RPAR_STREAMTYPE:
/* only the proxy can get these */
if (par->ctr == sizeof(par->streamtype) - 1)
goto hangup;
/*
* We can only expect to get this if we ourselves are
* in the state that we're waiting for it. If it comes
* later it's a protocol error.
*/
if (*state != LPCSPROX_WAIT_INITIAL_TX)
goto hangup;
/*
* We're the proxy, creating an SS on behalf of a
* client
*/
par->streamtype[par->ctr++] = (char)*cp++;
if (--par->rem)
break;
par->ps = RPAR_TYPE;
par->streamtype[par->ctr] = '\0';
lwsl_info("%s: proxy ss '%s', sssv%d, txcr %d\n",
__func__, par->streamtype,
par->protocol_version, par->txcr_out);
ssi->streamtype = par->streamtype;
if (par->txcr_out) // !!!
ssi->manual_initial_tx_credit = par->txcr_out;
/*
* Even for a synthetic SS proxing action like _lws_smd,
* we create an actual SS in the proxy representing the
* connection
*/
ssi->flags |= LWSSSINFLAGS_PROXIED;
ssi->sss_protocol_version = par->protocol_version;
ssi->client_pid = par->client_pid;
if (lws_ss_create(context, 0, ssi, parconn, pss,
NULL, NULL)) {
/*
* We're unable to create the onward secure
* stream he asked for... schedule a chance to
* inform him
*/
lwsl_err("%s: create '%s' fail\n", __func__,
par->streamtype);
*state = LPCSPROX_REPORTING_FAIL;
break;
} else {
lwsl_debug("%s: create '%s' OK\n",
__func__, par->streamtype);
*state = LPCSPROX_REPORTING_OK;
}
if (*pss) {
(*pss)->being_serialized = 1;
#if defined(LWS_WITH_SYS_SMD)
if ((*pss)->policy != &pol_smd)
/*
* In SMD case we overloaded the
* initial credit to be the class mask
*/
#endif
{
lwsl_info("%s: Created SS initial credit %d\n",
__func__, par->txcr_out);
(*pss)->info.manual_initial_tx_credit = par->txcr_out;
}
}
/* parent needs to schedule write on client conn */
break;
/* clientside states */
case RPAR_RESULT_CREATION:
case RPAR_RESULT_CREATION_RIDESHARE:
case RPAR_RESULT_CREATION_DSH:
case RPAR_STATEINDEX:
case RPAR_ORD3:
case RPAR_ORD2:
case RPAR_ORD1:
case RPAR_ORD0:
goto hangup;
default:
goto hangup;
}
}
return LWSSSSRET_OK;
hangup:
lwsl_cx_notice(context, "hangup");
return LWSSSSRET_DISCONNECT_ME;
}
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