diff options
Diffstat (limited to 'modules/http2/h2_ws.c')
| -rw-r--r-- | modules/http2/h2_ws.c | 362 |
1 files changed, 362 insertions, 0 deletions
diff --git a/modules/http2/h2_ws.c b/modules/http2/h2_ws.c new file mode 100644 index 0000000..396e6e1 --- /dev/null +++ b/modules/http2/h2_ws.c @@ -0,0 +1,362 @@ +/* Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include <assert.h> + +#include "apr.h" +#include "apr_strings.h" +#include "apr_lib.h" +#include "apr_sha1.h" +#include "apr_strmatch.h" + +#include <ap_mmn.h> + +#include <httpd.h> +#include <http_core.h> +#include <http_connection.h> +#include <http_protocol.h> +#include <http_request.h> +#include <http_log.h> +#include <http_ssl.h> +#include <http_vhost.h> +#include <util_filter.h> +#include <ap_mpm.h> + +#include "h2_private.h" +#include "h2_config.h" +#include "h2_conn_ctx.h" +#include "h2_headers.h" +#include "h2_request.h" +#include "h2_ws.h" + +#if H2_USE_WEBSOCKETS + +#include "apr_encode.h" /* H2_USE_WEBSOCKETS is conditional on APR 1.6+ */ + +static ap_filter_rec_t *c2_ws_out_filter_handle; + +struct ws_filter_ctx { + const char *ws_accept_base64; + int has_final_response; + int override_body; +}; + +/** + * Generate the "Sec-WebSocket-Accept" header field for the given key + * (base64 encoded) as defined in RFC 6455 ch. 4.2.2 step 5.3 + */ +static const char *gen_ws_accept(conn_rec *c, const char *key_base64) +{ + apr_byte_t dgst[APR_SHA1_DIGESTSIZE]; + const char ws_guid[] = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"; + apr_sha1_ctx_t sha1_ctx; + + apr_sha1_init(&sha1_ctx); + apr_sha1_update(&sha1_ctx, key_base64, (unsigned int)strlen(key_base64)); + apr_sha1_update(&sha1_ctx, ws_guid, (unsigned int)strlen(ws_guid)); + apr_sha1_final(dgst, &sha1_ctx); + + return apr_pencode_base64_binary(c->pool, dgst, sizeof(dgst), + APR_ENCODE_NONE, NULL); +} + +const h2_request *h2_ws_rewrite_request(const h2_request *req, + conn_rec *c2, int no_body) +{ + h2_conn_ctx_t *conn_ctx = h2_conn_ctx_get(c2); + h2_request *wsreq; + unsigned char key_raw[16]; + const char *key_base64, *accept_base64; + struct ws_filter_ctx *ws_ctx; + apr_status_t rv; + + if (!conn_ctx || !req->protocol || strcmp("websocket", req->protocol)) + return req; + + if (ap_cstr_casecmp("CONNECT", req->method)) { + ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c2, + "h2_c2(%s-%d): websocket request with method %s", + conn_ctx->id, conn_ctx->stream_id, req->method); + return req; + } + if (!req->scheme) { + ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c2, + "h2_c2(%s-%d): websocket CONNECT without :scheme", + conn_ctx->id, conn_ctx->stream_id); + return req; + } + if (!req->path) { + ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c2, + "h2_c2(%s-%d): websocket CONNECT without :path", + conn_ctx->id, conn_ctx->stream_id); + return req; + } + + ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c2, + "h2_c2(%s-%d): websocket CONNECT for %s", + conn_ctx->id, conn_ctx->stream_id, req->path); + /* Transform the HTTP/2 extended CONNECT to an internal GET using + * the HTTP/1.1 version of websocket connection setup. */ + wsreq = h2_request_clone(c2->pool, req); + wsreq->method = "GET"; + wsreq->protocol = NULL; + apr_table_set(wsreq->headers, "Upgrade", "websocket"); + apr_table_add(wsreq->headers, "Connection", "Upgrade"); + /* add Sec-WebSocket-Key header */ + rv = apr_generate_random_bytes(key_raw, sizeof(key_raw)); + if (rv != APR_SUCCESS) { + ap_log_error(APLOG_MARK, APLOG_CRIT, rv, NULL, APLOGNO(10461) + "error generating secret"); + return NULL; + } + key_base64 = apr_pencode_base64_binary(c2->pool, key_raw, sizeof(key_raw), + APR_ENCODE_NONE, NULL); + apr_table_set(wsreq->headers, "Sec-WebSocket-Key", key_base64); + /* This is now the request to process internally */ + + /* When this request gets processed and delivers a 101 response, + * we expect it to carry a "Sec-WebSocket-Accept" header with + * exactly the following value, as per RFC 6455. */ + accept_base64 = gen_ws_accept(c2, key_base64); + /* Add an output filter that intercepts generated responses: + * - if a valid WebSocket negotiation happens, transform the + * 101 response to a 200 + * - if a 2xx response happens, that does not pass the Accept test, + * return a 502 indicating that the URI seems not support the websocket + * protocol (RFC 8441 does not define this, but it seems the best + * choice) + * - if a 3xx, 4xx or 5xx response happens, forward this unchanged. + */ + ws_ctx = apr_pcalloc(c2->pool, sizeof(*ws_ctx)); + ws_ctx->ws_accept_base64 = accept_base64; + /* insert our filter just before the C2 core filter */ + ap_remove_output_filter_byhandle(c2->output_filters, "H2_C2_NET_OUT"); + ap_add_output_filter("H2_C2_WS_OUT", ws_ctx, NULL, c2); + ap_add_output_filter("H2_C2_NET_OUT", NULL, NULL, c2); + /* Mark the connection as being an Upgrade, with some special handling + * since the request needs an EOS, without the stream being closed */ + conn_ctx->is_upgrade = 1; + + return wsreq; +} + +static apr_bucket *make_valid_resp(conn_rec *c2, int status, + apr_table_t *headers, apr_table_t *notes) +{ + apr_table_t *nheaders, *nnotes; + + ap_assert(headers); + nheaders = apr_table_clone(c2->pool, headers); + apr_table_unset(nheaders, "Connection"); + apr_table_unset(nheaders, "Upgrade"); + apr_table_unset(nheaders, "Sec-WebSocket-Accept"); + nnotes = notes? apr_table_clone(c2->pool, notes) : + apr_table_make(c2->pool, 10); +#if AP_HAS_RESPONSE_BUCKETS + return ap_bucket_response_create(status, NULL, nheaders, nnotes, + c2->pool, c2->bucket_alloc); +#else + return h2_bucket_headers_create(c2->bucket_alloc, + h2_headers_create(status, nheaders, + nnotes, 0, c2->pool)); +#endif +} + +static apr_bucket *make_invalid_resp(conn_rec *c2, int status, + apr_table_t *notes) +{ + apr_table_t *nheaders, *nnotes; + + nheaders = apr_table_make(c2->pool, 10); + apr_table_setn(nheaders, "Content-Length", "0"); + nnotes = notes? apr_table_clone(c2->pool, notes) : + apr_table_make(c2->pool, 10); +#if AP_HAS_RESPONSE_BUCKETS + return ap_bucket_response_create(status, NULL, nheaders, nnotes, + c2->pool, c2->bucket_alloc); +#else + return h2_bucket_headers_create(c2->bucket_alloc, + h2_headers_create(status, nheaders, + nnotes, 0, c2->pool)); +#endif +} + +static void ws_handle_resp(conn_rec *c2, h2_conn_ctx_t *conn_ctx, + struct ws_filter_ctx *ws_ctx, apr_bucket *b) +{ +#if AP_HAS_RESPONSE_BUCKETS + ap_bucket_response *resp = b->data; +#else /* AP_HAS_RESPONSE_BUCKETS */ + h2_headers *resp = h2_bucket_headers_get(b); +#endif /* !AP_HAS_RESPONSE_BUCKETS */ + apr_bucket *b_override = NULL; + int is_final = 0; + int override_body = 0; + + if (ws_ctx->has_final_response) { + /* already did, nop */ + return; + } + + ap_log_cerror(APLOG_MARK, APLOG_TRACE2, 0, c2, + "h2_c2(%s-%d): H2_C2_WS_OUT inspecting response %d", + conn_ctx->id, conn_ctx->stream_id, resp->status); + if (resp->status == HTTP_SWITCHING_PROTOCOLS) { + /* The resource agreed to switch protocol. But this is only valid + * if it send back the correct Sec-WebSocket-Accept header value */ + const char *hd = apr_table_get(resp->headers, "Sec-WebSocket-Accept"); + if (hd && !strcmp(ws_ctx->ws_accept_base64, hd)) { + ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c2, + "h2_c2(%s-%d): websocket CONNECT, valid 101 Upgrade" + ", converting to 200 response", + conn_ctx->id, conn_ctx->stream_id); + b_override = make_valid_resp(c2, HTTP_OK, resp->headers, resp->notes); + is_final = 1; + } + else { + if (!hd) { + /* This points to someone being confused */ + ap_log_cerror(APLOG_MARK, APLOG_WARNING, 0, c2, APLOGNO(10462) + "h2_c2(%s-%d): websocket CONNECT, got 101 response " + "without Sec-WebSocket-Accept header", + conn_ctx->id, conn_ctx->stream_id); + } + else { + /* This points to a bug, either in our WebSockets negotiation + * or in the request processings implementation of WebSockets */ + ap_log_cerror(APLOG_MARK, APLOG_ERR, 0, c2, APLOGNO(10463) + "h2_c2(%s-%d): websocket CONNECT, 101 response " + "with 'Sec-WebSocket-Accept: %s' but expected %s", + conn_ctx->id, conn_ctx->stream_id, hd, + ws_ctx->ws_accept_base64); + } + b_override = make_invalid_resp(c2, HTTP_BAD_GATEWAY, resp->notes); + override_body = is_final = 1; + } + } + else if (resp->status < 200) { + /* other intermediate response, pass through */ + } + else if (resp->status < 300) { + /* Failure, we might be talking to a plain http resource */ + ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c2, + "h2_c2(%s-%d): websocket CONNECT, invalid response %d", + conn_ctx->id, conn_ctx->stream_id, resp->status); + b_override = make_invalid_resp(c2, HTTP_BAD_GATEWAY, resp->notes); + override_body = is_final = 1; + } + else { + /* error response, pass through. */ + ws_ctx->has_final_response = 1; + } + + if (b_override) { + APR_BUCKET_INSERT_BEFORE(b, b_override); + apr_bucket_delete(b); + b = b_override; + } + if (override_body) { + APR_BUCKET_INSERT_AFTER(b, apr_bucket_eos_create(c2->bucket_alloc)); + ws_ctx->override_body = 1; + } + if (is_final) { + ws_ctx->has_final_response = 1; + conn_ctx->has_final_response = 1; + } +} + +static apr_status_t h2_c2_ws_filter_out(ap_filter_t* f, apr_bucket_brigade* bb) +{ + struct ws_filter_ctx *ws_ctx = f->ctx; + h2_conn_ctx_t *conn_ctx = h2_conn_ctx_get(f->c); + apr_bucket *b, *bnext; + + ap_assert(conn_ctx); + if (ws_ctx->override_body) { + /* We have overridden the original response and also its body. + * If this filter is called again, we signal a hard abort to + * allow processing to terminate at the earliest. */ + f->c->aborted = 1; + return APR_ECONNABORTED; + } + + /* Inspect the brigade, looking for RESPONSE/HEADER buckets. + * Remember, this filter is only active for client websocket CONNECT + * requests that we translated to an internal GET with websocket + * headers. + * We inspect the repsone to see if the internal resource actually + * agrees to talk websocket or is "just" a normal HTTP resource that + * ignored the websocket request headers. */ + for (b = APR_BRIGADE_FIRST(bb); + b != APR_BRIGADE_SENTINEL(bb); + b = bnext) + { + bnext = APR_BUCKET_NEXT(b); + if (APR_BUCKET_IS_METADATA(b)) { +#if AP_HAS_RESPONSE_BUCKETS + if (AP_BUCKET_IS_RESPONSE(b)) { +#else + if (H2_BUCKET_IS_HEADERS(b)) { +#endif /* !AP_HAS_RESPONSE_BUCKETS */ + ws_handle_resp(f->c, conn_ctx, ws_ctx, b); + continue; + } + } + else if (ws_ctx->override_body) { + apr_bucket_delete(b); + } + } + return ap_pass_brigade(f->next, bb); +} + +static int ws_post_read(request_rec *r) +{ + + if (r->connection->master) { + h2_conn_ctx_t *conn_ctx = h2_conn_ctx_get(r->connection); + if (conn_ctx && conn_ctx->is_upgrade && + !h2_config_sgeti(r->server, H2_CONF_WEBSOCKETS)) { + return HTTP_NOT_IMPLEMENTED; + } + } + return DECLINED; +} + +void h2_ws_register_hooks(void) +{ + ap_hook_post_read_request(ws_post_read, NULL, NULL, APR_HOOK_MIDDLE); + c2_ws_out_filter_handle = + ap_register_output_filter("H2_C2_WS_OUT", h2_c2_ws_filter_out, + NULL, AP_FTYPE_NETWORK); +} + +#else /* H2_USE_WEBSOCKETS */ + +const h2_request *h2_ws_rewrite_request(const h2_request *req, + conn_rec *c2, int no_body) +{ + (void)c2; + (void)no_body; + /* no rewriting */ + return req; +} + +void h2_ws_register_hooks(void) +{ + /* NOP */ +} + +#endif /* H2_USE_WEBSOCKETS (else part) */ |