diff options
Diffstat (limited to 'modules/filters/mod_reqtimeout.c')
| -rw-r--r-- | modules/filters/mod_reqtimeout.c | 670 |
1 files changed, 670 insertions, 0 deletions
diff --git a/modules/filters/mod_reqtimeout.c b/modules/filters/mod_reqtimeout.c new file mode 100644 index 0000000..0ebd78a --- /dev/null +++ b/modules/filters/mod_reqtimeout.c @@ -0,0 +1,670 @@ +/* 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 "httpd.h" +#include "http_config.h" +#include "http_request.h" +#include "http_connection.h" +#include "http_protocol.h" +#include "http_log.h" +#include "http_core.h" +#include "util_filter.h" +#define APR_WANT_STRFUNC +#include "apr_strings.h" +#include "apr_version.h" + +module AP_MODULE_DECLARE_DATA reqtimeout_module; + +#define UNSET -1 +#define MRT_DEFAULT_handshake_TIMEOUT 0 /* disabled */ +#define MRT_DEFAULT_handshake_MAX_TIMEOUT 0 +#define MRT_DEFAULT_handshake_MIN_RATE 0 +#define MRT_DEFAULT_header_TIMEOUT 20 +#define MRT_DEFAULT_header_MAX_TIMEOUT 40 +#define MRT_DEFAULT_header_MIN_RATE 500 +#define MRT_DEFAULT_body_TIMEOUT 20 +#define MRT_DEFAULT_body_MAX_TIMEOUT 0 +#define MRT_DEFAULT_body_MIN_RATE 500 + +typedef struct +{ + int timeout; /* timeout in secs */ + int max_timeout; /* max timeout in secs */ + int min_rate; /* min rate in bytes/s */ + apr_time_t rate_factor; /* scale factor (#usecs per min_rate) */ +} reqtimeout_stage_t; + +typedef struct +{ + reqtimeout_stage_t handshake; /* Handshaking (TLS) */ + reqtimeout_stage_t header; /* Reading the HTTP header */ + reqtimeout_stage_t body; /* Reading the HTTP body */ +} reqtimeout_srv_cfg; + +/* this struct is used both as conn_config and as filter context */ +typedef struct +{ + apr_time_t timeout_at; + apr_time_t max_timeout_at; + reqtimeout_stage_t cur_stage; + int in_keep_alive; + char *type; + apr_socket_t *socket; + apr_bucket_brigade *tmpbb; +} reqtimeout_con_cfg; + +static const char *const reqtimeout_filter_name = "reqtimeout"; +static int default_handshake_rate_factor; +static int default_header_rate_factor; +static int default_body_rate_factor; + +static void extend_timeout(reqtimeout_con_cfg *ccfg, apr_bucket_brigade *bb) +{ + apr_off_t len; + apr_time_t new_timeout_at; + + if (apr_brigade_length(bb, 0, &len) != APR_SUCCESS || len <= 0) + return; + + new_timeout_at = ccfg->timeout_at + len * ccfg->cur_stage.rate_factor; + if (ccfg->max_timeout_at > 0 && new_timeout_at > ccfg->max_timeout_at) { + ccfg->timeout_at = ccfg->max_timeout_at; + } + else { + ccfg->timeout_at = new_timeout_at; + } +} + +static apr_status_t check_time_left(reqtimeout_con_cfg *ccfg, + apr_time_t *time_left_p, + apr_time_t now) +{ + if (!now) + now = apr_time_now(); + *time_left_p = ccfg->timeout_at - now; + if (*time_left_p <= 0) + return APR_TIMEUP; + + if (*time_left_p < apr_time_from_sec(1)) { + *time_left_p = apr_time_from_sec(1); + } + return APR_SUCCESS; +} + +static apr_status_t have_lf_or_eos(apr_bucket_brigade *bb) +{ + apr_bucket *b = APR_BRIGADE_LAST(bb); + + for ( ; b != APR_BRIGADE_SENTINEL(bb) ; b = APR_BUCKET_PREV(b) ) { + const char *str; + apr_size_t len; + apr_status_t rv; + + if (APR_BUCKET_IS_EOS(b)) + return APR_SUCCESS; + + if (APR_BUCKET_IS_METADATA(b)) + continue; + + rv = apr_bucket_read(b, &str, &len, APR_BLOCK_READ); + if (rv != APR_SUCCESS) + return rv; + + if (len == 0) + continue; + + if (str[len-1] == APR_ASCII_LF) + return APR_SUCCESS; + } + return APR_INCOMPLETE; +} + +/* + * Append bbIn to bbOut and merge small buckets, to avoid DoS by high memory + * usage + */ +static apr_status_t brigade_append(apr_bucket_brigade *bbOut, apr_bucket_brigade *bbIn) +{ + while (!APR_BRIGADE_EMPTY(bbIn)) { + apr_bucket *e = APR_BRIGADE_FIRST(bbIn); + const char *str; + apr_size_t len; + apr_status_t rv; + + rv = apr_bucket_read(e, &str, &len, APR_BLOCK_READ); + if (rv != APR_SUCCESS) { + return rv; + } + + APR_BUCKET_REMOVE(e); + if (APR_BUCKET_IS_METADATA(e) || len > APR_BUCKET_BUFF_SIZE/4) { + APR_BRIGADE_INSERT_TAIL(bbOut, e); + } + else { + if (len > 0) { + rv = apr_brigade_write(bbOut, NULL, NULL, str, len); + if (rv != APR_SUCCESS) { + apr_bucket_destroy(e); + return rv; + } + } + apr_bucket_destroy(e); + } + } + return APR_SUCCESS; +} + + +#define MIN(x,y) ((x) < (y) ? (x) : (y)) +static apr_status_t reqtimeout_filter(ap_filter_t *f, + apr_bucket_brigade *bb, + ap_input_mode_t mode, + apr_read_type_e block, + apr_off_t readbytes) +{ + apr_time_t time_left; + apr_time_t now = 0; + apr_status_t rv; + apr_interval_time_t saved_sock_timeout = UNSET; + reqtimeout_con_cfg *ccfg = f->ctx; + + if (ccfg->in_keep_alive) { + /* For this read[_request line()], wait for the first byte using the + * normal keep-alive timeout (hence don't take this expected idle time + * into account to setup the connection expiry below). + */ + ccfg->in_keep_alive = 0; + rv = ap_get_brigade(f->next, bb, AP_MODE_SPECULATIVE, block, 1); + if (rv != APR_SUCCESS || APR_BRIGADE_EMPTY(bb)) { + return rv; + } + apr_brigade_cleanup(bb); + } + + if (ccfg->cur_stage.timeout > 0) { + /* set new timeout */ + now = apr_time_now(); + ccfg->timeout_at = now + apr_time_from_sec(ccfg->cur_stage.timeout); + ccfg->cur_stage.timeout = 0; + if (ccfg->cur_stage.max_timeout > 0) { + ccfg->max_timeout_at = now + apr_time_from_sec(ccfg->cur_stage.max_timeout); + ccfg->cur_stage.max_timeout = 0; + } + } + else if (ccfg->timeout_at == 0) { + /* no timeout set, or in between requests */ + return ap_get_brigade(f->next, bb, mode, block, readbytes); + } + + if (!ccfg->socket) { + ccfg->socket = ap_get_conn_socket(f->c); + } + + rv = check_time_left(ccfg, &time_left, now); + if (rv != APR_SUCCESS) + goto out; + + if (block == APR_NONBLOCK_READ || mode == AP_MODE_INIT + || mode == AP_MODE_EATCRLF) { + rv = ap_get_brigade(f->next, bb, mode, block, readbytes); + if (ccfg->cur_stage.rate_factor && rv == APR_SUCCESS) { + extend_timeout(ccfg, bb); + } + return rv; + } + + rv = apr_socket_timeout_get(ccfg->socket, &saved_sock_timeout); + AP_DEBUG_ASSERT(rv == APR_SUCCESS); + + rv = apr_socket_timeout_set(ccfg->socket, MIN(time_left, saved_sock_timeout)); + AP_DEBUG_ASSERT(rv == APR_SUCCESS); + + if (mode == AP_MODE_GETLINE) { + /* + * For a blocking AP_MODE_GETLINE read, apr_brigade_split_line() + * would loop until a whole line has been read. As this would make it + * impossible to enforce a total timeout, we only do non-blocking + * reads. + */ + apr_off_t remaining = HUGE_STRING_LEN; + do { + apr_off_t bblen; +#if APR_MAJOR_VERSION < 2 + apr_int32_t nsds; + apr_interval_time_t poll_timeout; + apr_pollfd_t pollset; +#endif + + rv = ap_get_brigade(f->next, bb, AP_MODE_GETLINE, APR_NONBLOCK_READ, remaining); + if (rv != APR_SUCCESS && !APR_STATUS_IS_EAGAIN(rv)) { + break; + } + + if (!APR_BRIGADE_EMPTY(bb)) { + if (ccfg->cur_stage.rate_factor) { + extend_timeout(ccfg, bb); + } + + rv = have_lf_or_eos(bb); + if (rv != APR_INCOMPLETE) { + break; + } + + rv = apr_brigade_length(bb, 1, &bblen); + if (rv != APR_SUCCESS) { + break; + } + remaining -= bblen; + if (remaining <= 0) { + break; + } + + /* Haven't got a whole line yet, save what we have ... */ + if (!ccfg->tmpbb) { + ccfg->tmpbb = apr_brigade_create(f->c->pool, f->c->bucket_alloc); + } + rv = brigade_append(ccfg->tmpbb, bb); + if (rv != APR_SUCCESS) + break; + } + + /* ... and wait for more */ +#if APR_MAJOR_VERSION < 2 + pollset.p = f->c->pool; + pollset.desc_type = APR_POLL_SOCKET; + pollset.reqevents = APR_POLLIN|APR_POLLHUP; + pollset.desc.s = ccfg->socket; + apr_socket_timeout_get(ccfg->socket, &poll_timeout); + rv = apr_poll(&pollset, 1, &nsds, poll_timeout); +#else + rv = apr_socket_wait(ccfg->socket, APR_WAIT_READ); +#endif + if (rv != APR_SUCCESS) + break; + + rv = check_time_left(ccfg, &time_left, 0); + if (rv != APR_SUCCESS) + break; + + rv = apr_socket_timeout_set(ccfg->socket, + MIN(time_left, saved_sock_timeout)); + AP_DEBUG_ASSERT(rv == APR_SUCCESS); + + } while (1); + + if (ccfg->tmpbb) + APR_BRIGADE_PREPEND(bb, ccfg->tmpbb); + + } + else { /* mode != AP_MODE_GETLINE */ + rv = ap_get_brigade(f->next, bb, mode, block, readbytes); + /* Don't extend the timeout in speculative mode, wait for + * the real (relevant) bytes to be asked later, within the + * currently allotted time. + */ + if (ccfg->cur_stage.rate_factor && rv == APR_SUCCESS + && mode != AP_MODE_SPECULATIVE) { + extend_timeout(ccfg, bb); + } + } + + apr_socket_timeout_set(ccfg->socket, saved_sock_timeout); + +out: + if (APR_STATUS_IS_TIMEUP(rv)) { + ap_log_cerror(APLOG_MARK, APLOG_INFO, 0, f->c, APLOGNO(01382) + "Request %s read timeout", ccfg->type); + /* + * If we allow a normal lingering close, the client may keep this + * process/thread busy for another 30s (MAX_SECS_TO_LINGER). + * Therefore we tell ap_lingering_close() to shorten this period to + * 2s (SECONDS_TO_LINGER). + */ + apr_table_setn(f->c->notes, "short-lingering-close", "1"); + + /* + * Also, we must not allow keep-alive requests, as + * ap_finalize_protocol() may ignore our error status (if the timeout + * happened on a request body that is discarded). + */ + f->c->keepalive = AP_CONN_CLOSE; + } + return rv; +} + +static apr_status_t reqtimeout_eor(ap_filter_t *f, apr_bucket_brigade *bb) +{ + if (!APR_BRIGADE_EMPTY(bb) && AP_BUCKET_IS_EOR(APR_BRIGADE_LAST(bb))) { + reqtimeout_con_cfg *ccfg = f->ctx; + ccfg->timeout_at = 0; + } + return ap_pass_brigade(f->next, bb); +} + +#define INIT_STAGE(cfg, ccfg, stage) do { \ + if (cfg->stage.timeout != UNSET) { \ + ccfg->cur_stage.timeout = cfg->stage.timeout; \ + ccfg->cur_stage.max_timeout = cfg->stage.max_timeout; \ + ccfg->cur_stage.rate_factor = cfg->stage.rate_factor; \ + } \ + else { \ + ccfg->cur_stage.timeout = MRT_DEFAULT_##stage##_TIMEOUT; \ + ccfg->cur_stage.max_timeout = MRT_DEFAULT_##stage##_MAX_TIMEOUT; \ + ccfg->cur_stage.rate_factor = default_##stage##_rate_factor; \ + } \ +} while (0) + +static int reqtimeout_init(conn_rec *c) +{ + reqtimeout_con_cfg *ccfg; + reqtimeout_srv_cfg *cfg; + + cfg = ap_get_module_config(c->base_server->module_config, + &reqtimeout_module); + AP_DEBUG_ASSERT(cfg != NULL); + + /* For compatibility, handshake timeout is disabled when UNSET (< 0) */ + if (cfg->handshake.timeout <= 0 + && cfg->header.timeout == 0 + && cfg->body.timeout == 0) { + /* disabled for this vhost */ + return DECLINED; + } + + ccfg = ap_get_module_config(c->conn_config, &reqtimeout_module); + if (ccfg == NULL) { + ccfg = apr_pcalloc(c->pool, sizeof(reqtimeout_con_cfg)); + ap_set_module_config(c->conn_config, &reqtimeout_module, ccfg); + ap_add_output_filter(reqtimeout_filter_name, ccfg, NULL, c); + ap_add_input_filter(reqtimeout_filter_name, ccfg, NULL, c); + + ccfg->type = "handshake"; + if (cfg->handshake.timeout > 0) { + INIT_STAGE(cfg, ccfg, handshake); + } + } + + /* we are not handling the connection, we just do initialization */ + return DECLINED; +} + +static void reqtimeout_before_header(request_rec *r, conn_rec *c) +{ + reqtimeout_srv_cfg *cfg; + reqtimeout_con_cfg *ccfg = + ap_get_module_config(c->conn_config, &reqtimeout_module); + + if (ccfg == NULL) { + /* not configured for this connection */ + return; + } + + cfg = ap_get_module_config(c->base_server->module_config, + &reqtimeout_module); + AP_DEBUG_ASSERT(cfg != NULL); + + /* (Re)set the state for this new request, but ccfg->socket and + * ccfg->tmpbb which have the lifetime of the connection. + */ + ccfg->type = "header"; + ccfg->timeout_at = 0; + ccfg->max_timeout_at = 0; + ccfg->in_keep_alive = (c->keepalives > 0); + INIT_STAGE(cfg, ccfg, header); +} + +static int reqtimeout_before_body(request_rec *r) +{ + reqtimeout_srv_cfg *cfg; + reqtimeout_con_cfg *ccfg = + ap_get_module_config(r->connection->conn_config, &reqtimeout_module); + + if (ccfg == NULL) { + /* not configured for this connection */ + return OK; + } + cfg = ap_get_module_config(r->server->module_config, + &reqtimeout_module); + AP_DEBUG_ASSERT(cfg != NULL); + + ccfg->type = "body"; + ccfg->timeout_at = 0; + ccfg->max_timeout_at = 0; + if (r->method_number == M_CONNECT) { + /* disabled for a CONNECT request */ + ccfg->cur_stage.timeout = 0; + } + else { + INIT_STAGE(cfg, ccfg, body); + } + return OK; +} + +#define UNSET_STAGE(cfg, stage) do { \ + cfg->stage.timeout = UNSET; \ + cfg->stage.max_timeout = UNSET; \ + cfg->stage.min_rate = UNSET; \ +} while (0) + +static void *reqtimeout_create_srv_config(apr_pool_t *p, server_rec *s) +{ + reqtimeout_srv_cfg *cfg = apr_pcalloc(p, sizeof(reqtimeout_srv_cfg)); + + UNSET_STAGE(cfg, handshake); + UNSET_STAGE(cfg, header); + UNSET_STAGE(cfg, body); + + return cfg; +} + +#define MERGE_INT(cfg, base, add, val) \ + cfg->val = (add->val == UNSET) ? base->val : add->val +#define MERGE_STAGE(cfg, base, add, stage) do { \ + MERGE_INT(cfg, base, add, stage.timeout); \ + MERGE_INT(cfg, base, add, stage.max_timeout); \ + MERGE_INT(cfg, base, add, stage.min_rate); \ + cfg->stage.rate_factor = (cfg->stage.min_rate == UNSET) \ + ? base->stage.rate_factor \ + : add->stage.rate_factor; \ +} while (0) + +static void *reqtimeout_merge_srv_config(apr_pool_t *p, void *base_, void *add_) +{ + reqtimeout_srv_cfg *base = base_; + reqtimeout_srv_cfg *add = add_; + reqtimeout_srv_cfg *cfg = apr_pcalloc(p, sizeof(reqtimeout_srv_cfg)); + + MERGE_STAGE(cfg, base, add, handshake); + MERGE_STAGE(cfg, base, add, header); + MERGE_STAGE(cfg, base, add, body); + + return cfg; +} + +static const char *parse_int(apr_pool_t *p, const char *arg, int *val) +{ + char *endptr; + *val = strtol(arg, &endptr, 10); + + if (arg == endptr) { + return apr_psprintf(p, "Value '%s' not numerical", endptr); + } + if (*endptr != '\0') { + return apr_psprintf(p, "Cannot parse '%s'", endptr); + } + if (*val < 0) { + return "Value must be non-negative"; + } + return NULL; +} + +static const char *set_reqtimeout_param(reqtimeout_srv_cfg *conf, + apr_pool_t *p, + const char *key, + const char *val) +{ + const char *ret = NULL; + char *rate_str = NULL, *initial_str, *max_str = NULL; + reqtimeout_stage_t *stage; + + if (!strcasecmp(key, "handshake")) { + stage = &conf->handshake; + } + else if (!strcasecmp(key, "header")) { + stage = &conf->header; + } + else if (!strcasecmp(key, "body")) { + stage = &conf->body; + } + else { + return "Unknown RequestReadTimeout parameter"; + } + + memset(stage, 0, sizeof(*stage)); + + if ((rate_str = ap_strcasestr(val, ",minrate="))) { + initial_str = apr_pstrndup(p, val, rate_str - val); + rate_str += strlen(",minrate="); + ret = parse_int(p, rate_str, &stage->min_rate); + if (ret) + return ret; + + if (stage->min_rate == 0) + return "Minimum data rate must be larger than 0"; + + if ((max_str = strchr(initial_str, '-'))) { + *max_str++ = '\0'; + ret = parse_int(p, max_str, &stage->max_timeout); + if (ret) + return ret; + } + + ret = parse_int(p, initial_str, &stage->timeout); + } + else { + if (ap_strchr_c(val, '-')) + return "Must set MinRate option if using timeout range"; + ret = parse_int(p, val, &stage->timeout); + } + if (ret) + return ret; + + if (stage->max_timeout && stage->timeout >= stage->max_timeout) { + return "Maximum timeout must be larger than initial timeout"; + } + + if (stage->min_rate) { + stage->rate_factor = apr_time_from_sec(1) / stage->min_rate; + } + + return NULL; +} + +static const char *set_reqtimeouts(cmd_parms *cmd, void *mconfig, + const char *arg) +{ + reqtimeout_srv_cfg *conf = + ap_get_module_config(cmd->server->module_config, + &reqtimeout_module); + + while (*arg) { + char *word, *val; + const char *err; + + word = ap_getword_conf(cmd->temp_pool, &arg); + val = strchr(word, '='); + if (!val) { + return "Invalid RequestReadTimeout parameter. Parameter must be " + "in the form 'key=value'"; + } + else + *val++ = '\0'; + + err = set_reqtimeout_param(conf, cmd->pool, word, val); + + if (err) + return apr_psprintf(cmd->temp_pool, "RequestReadTimeout: %s=%s: %s", + word, val, err); + } + + return NULL; + +} + +static void reqtimeout_hooks(apr_pool_t *pool) +{ + /* + * mod_ssl is AP_FTYPE_CONNECTION + 5 and mod_reqtimeout needs to + * be called before mod_ssl for the handshake stage to catch SSL traffic. + */ + ap_register_input_filter(reqtimeout_filter_name, reqtimeout_filter, NULL, + AP_FTYPE_CONNECTION + 8); + + /* + * We need to pause timeout detection in between requests, for + * speculative and non-blocking reads, so between each outgoing EOR + * and the next pre_read_request call. + */ + ap_register_output_filter(reqtimeout_filter_name, reqtimeout_eor, NULL, + AP_FTYPE_CONNECTION); + + /* + * mod_reqtimeout needs to be called before ap_process_http_request (which + * is run at APR_HOOK_REALLY_LAST) but after all other protocol modules. + * This ensures that it only influences normal http connections and not + * e.g. mod_ftp. We still process it first though, for the handshake stage + * to work with/before mod_ssl, but since it's disabled by default it won't + * influence non-HTTP modules unless configured explicitly. Also, if + * mod_reqtimeout used the pre_connection hook, it would be inserted on + * mod_proxy's backend connections, and we don't want this. + */ + ap_hook_process_connection(reqtimeout_init, NULL, NULL, APR_HOOK_FIRST); + + ap_hook_pre_read_request(reqtimeout_before_header, NULL, NULL, + APR_HOOK_MIDDLE); + ap_hook_post_read_request(reqtimeout_before_body, NULL, NULL, + APR_HOOK_MIDDLE); + +#if MRT_DEFAULT_handshake_MIN_RATE + default_handshake_rate_factor = apr_time_from_sec(1) / + MRT_DEFAULT_handshake_MIN_RATE; +#endif +#if MRT_DEFAULT_header_MIN_RATE + default_header_rate_factor = apr_time_from_sec(1) / + MRT_DEFAULT_header_MIN_RATE; +#endif +#if MRT_DEFAULT_body_MIN_RATE + default_body_rate_factor = apr_time_from_sec(1) / + MRT_DEFAULT_body_MIN_RATE; +#endif +} + +static const command_rec reqtimeout_cmds[] = { + AP_INIT_RAW_ARGS("RequestReadTimeout", set_reqtimeouts, NULL, RSRC_CONF, + "Set various timeout parameters for TLS handshake and/or " + "reading request headers and body"), + {NULL} +}; + +AP_DECLARE_MODULE(reqtimeout) = { + STANDARD20_MODULE_STUFF, + NULL, /* create per-dir config structures */ + NULL, /* merge per-dir config structures */ + reqtimeout_create_srv_config, /* create per-server config structures */ + reqtimeout_merge_srv_config, /* merge per-server config structures */ + reqtimeout_cmds, /* table of config file commands */ + reqtimeout_hooks +}; |