/* 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. */ /* * mod_setenvif.c * Set environment variables based on matching request headers or * attributes against regex strings * * Paul Sutton <paul@ukweb.com> 27 Oct 1996 * Based on mod_browser by Alexei Kosut <akosut@organic.com> */ /* * Used to set environment variables based on the incoming request headers, * or some selected other attributes of the request (e.g., the remote host * name). * * Usage: * * SetEnvIf name regex var ... * * where name is either a HTTP request header name, or one of the * special values (see below). 'name' may be a regex when it is used * to specify an HTTP request header name. The 'value' of the header & (or the value of the special value from below) are compared against * the regex argument. If this is a simple string, a simple sub-string * match is performed. Otherwise, a request expression match is * done. If the value matches the string or regular expression, the * environment variables listed as var ... are set. Each var can * be in one of three formats: var, which sets the named variable * (the value value "1"); var=value, which sets the variable to * the given value; or !var, which unsets the variable is it has * been previously set. * * Normally the strings are compared with regard to case. To ignore * case, use the directive SetEnvIfNoCase instead. * * Special values for 'name' are: * * server_addr IP address of interface on which request arrived * (analogous to SERVER_ADDR set in ap_add_common_vars()) * remote_host Remote host name (if available) * remote_addr Remote IP address * request_method Request method (GET, POST, etc) * request_uri Requested URI * * Examples: * * To set the enviroment variable LOCALHOST if the client is the local * machine: * * SetEnvIf remote_addr 127.0.0.1 LOCALHOST * * To set LOCAL if the client is the local host, or within our company's * domain (192.168.10): * * SetEnvIf remote_addr 192.168.10. LOCAL * SetEnvIf remote_addr 127.0.0.1 LOCALHOST * * This could be written as: * * SetEnvIf remote_addr (127.0.0.1|192.168.10.) LOCAL * * To set HAVE_TS if the client request contains any header beginning * with "TS" with a value beginning with a lower case alphabet: * * SetEnvIf ^TS* ^[a-z].* HAVE_TS */ #include "apr.h" #include "apr_strings.h" #include "apr_strmatch.h" #define APR_WANT_STRFUNC #include "apr_want.h" #include "ap_config.h" #include "httpd.h" #include "http_config.h" #include "http_core.h" #include "http_log.h" #include "http_protocol.h" enum special { SPECIAL_NOT, SPECIAL_REMOTE_ADDR, SPECIAL_REMOTE_HOST, SPECIAL_REQUEST_URI, SPECIAL_REQUEST_METHOD, SPECIAL_REQUEST_PROTOCOL, SPECIAL_SERVER_ADDR }; typedef struct { char *name; /* header name */ ap_regex_t *pnamereg; /* compiled header name regex */ char *regex; /* regex to match against */ ap_regex_t *preg; /* compiled regex */ const apr_strmatch_pattern *pattern; /* non-regex pattern to match */ apr_table_t *features; /* env vars to set (or unset) */ enum special special_type; /* is it a "special" header ? */ int icase; /* ignoring case? */ } sei_entry; typedef struct { apr_array_header_t *conditionals; } sei_cfg_rec; module AP_MODULE_DECLARE_DATA setenvif_module; /* * These routines, the create- and merge-config functions, are called * for both the server-wide and the per-directory contexts. This is * because the different definitions are used at different times; the * server-wide ones are used in the post-read-request phase, and the * per-directory ones are used during the header-parse phase (after * the URI has been mapped to a file and we have anything from the * .htaccess file and <Directory> and <Files> containers). */ static void *create_setenvif_config(apr_pool_t *p) { sei_cfg_rec *new = (sei_cfg_rec *) apr_palloc(p, sizeof(sei_cfg_rec)); new->conditionals = apr_array_make(p, 20, sizeof(sei_entry)); return (void *) new; } static void *create_setenvif_config_svr(apr_pool_t *p, server_rec *dummy) { return create_setenvif_config(p); } static void *create_setenvif_config_dir(apr_pool_t *p, char *dummy) { return create_setenvif_config(p); } static void *merge_setenvif_config(apr_pool_t *p, void *basev, void *overridesv) { sei_cfg_rec *a = apr_pcalloc(p, sizeof(sei_cfg_rec)); sei_cfg_rec *base = basev, *overrides = overridesv; a->conditionals = apr_array_append(p, base->conditionals, overrides->conditionals); return a; } /* * any non-NULL magic constant will do... used to indicate if AP_REG_ICASE should * be used */ #define ICASE_MAGIC ((void *)(&setenvif_module)) #define SEI_MAGIC_HEIRLOOM "setenvif-phase-flag" static int is_header_regex(apr_pool_t *p, const char* name) { /* If a Header name contains characters other than: * -,_,[A-Z\, [a-z] and [0-9]. * assume the header name is a regular expression. */ ap_regex_t *preg = ap_pregcomp(p, "^[-A-Za-z0-9_]*$", (AP_REG_EXTENDED | AP_REG_NOSUB )); ap_assert(preg != NULL); if (ap_regexec(preg, name, 0, NULL, 0)) { return 1; } return 0; } /* If the input string does not take advantage of regular * expression metacharacters, return a pointer to an equivalent * string that can be searched using apr_strmatch(). (The * returned string will often be the input string. But if * the input string contains escaped characters, the returned * string will be a copy with the escapes removed.) */ static const char *non_regex_pattern(apr_pool_t *p, const char *s) { const char *src = s; int escapes_found = 0; int in_escape = 0; while (*src) { switch (*src) { case '^': case '.': case '$': case '|': case '(': case ')': case '[': case ']': case '*': case '+': case '?': case '{': case '}': if (!in_escape) { return NULL; } in_escape = 0; break; case '\\': if (!in_escape) { in_escape = 1; escapes_found = 1; } else { in_escape = 0; } break; default: if (in_escape) { return NULL; } break; } src++; } if (!escapes_found) { return s; } else { char *unescaped = (char *)apr_palloc(p, src - s + 1); char *dst = unescaped; src = s; do { if (*src == '\\') { src++; } } while ((*dst++ = *src++)); return unescaped; } } static const char *add_setenvif_core(cmd_parms *cmd, void *mconfig, char *fname, const char *args) { char *regex; const char *simple_pattern; const char *feature; sei_cfg_rec *sconf; sei_entry *new; sei_entry *entries; char *var; int i; int beenhere = 0; int icase; /* * Determine from our context into which record to put the entry. * cmd->path == NULL means we're in server-wide context; otherwise, * we're dealing with a per-directory setting. */ sconf = (cmd->path != NULL) ? (sei_cfg_rec *) mconfig : (sei_cfg_rec *) ap_get_module_config(cmd->server->module_config, &setenvif_module); entries = (sei_entry *) sconf->conditionals->elts; /* get regex */ regex = ap_getword_conf(cmd->pool, &args); if (!*regex) { return apr_pstrcat(cmd->pool, "Missing regular expression for ", cmd->cmd->name, NULL); } /* * If we've already got a sei_entry with the same name we want to * just copy the name pointer... so that later on we can compare * two header names just by comparing the pointers. */ for (i = 0; i < sconf->conditionals->nelts; ++i) { new = &entries[i]; if (!strcasecmp(new->name, fname)) { fname = new->name; break; } } /* if the last entry has an identical headername and regex then * merge with it */ i = sconf->conditionals->nelts - 1; icase = cmd->info == ICASE_MAGIC; if (i < 0 || entries[i].name != fname || entries[i].icase != icase || strcmp(entries[i].regex, regex)) { /* no match, create a new entry */ new = apr_array_push(sconf->conditionals); new->name = fname; new->regex = regex; new->icase = icase; if ((simple_pattern = non_regex_pattern(cmd->pool, regex))) { new->pattern = apr_strmatch_precompile(cmd->pool, simple_pattern, !icase); if (new->pattern == NULL) { return apr_pstrcat(cmd->pool, cmd->cmd->name, " pattern could not be compiled.", NULL); } new->preg = NULL; } else { new->preg = ap_pregcomp(cmd->pool, regex, (AP_REG_EXTENDED | (icase ? AP_REG_ICASE : 0))); if (new->preg == NULL) { return apr_pstrcat(cmd->pool, cmd->cmd->name, " regex could not be compiled.", NULL); } new->pattern = NULL; } new->features = apr_table_make(cmd->pool, 2); if (!strcasecmp(fname, "remote_addr")) { new->special_type = SPECIAL_REMOTE_ADDR; } else if (!strcasecmp(fname, "remote_host")) { new->special_type = SPECIAL_REMOTE_HOST; } else if (!strcasecmp(fname, "request_uri")) { new->special_type = SPECIAL_REQUEST_URI; } else if (!strcasecmp(fname, "request_method")) { new->special_type = SPECIAL_REQUEST_METHOD; } else if (!strcasecmp(fname, "request_protocol")) { new->special_type = SPECIAL_REQUEST_PROTOCOL; } else if (!strcasecmp(fname, "server_addr")) { new->special_type = SPECIAL_SERVER_ADDR; } else { new->special_type = SPECIAL_NOT; /* Handle fname as a regular expression. * If fname a simple header string, identify as such * (new->pnamereg = NULL) to avoid the overhead of searching * through headers_in for a regex match. */ if (is_header_regex(cmd->pool, fname)) { new->pnamereg = ap_pregcomp(cmd->pool, fname, (AP_REG_EXTENDED | AP_REG_NOSUB | (icase ? AP_REG_ICASE : 0))); if (new->pnamereg == NULL) return apr_pstrcat(cmd->pool, cmd->cmd->name, "Header name regex could not be " "compiled.", NULL); } else { new->pnamereg = NULL; } } } else { new = &entries[i]; } for ( ; ; ) { feature = ap_getword_conf(cmd->pool, &args); if (!*feature) { break; } beenhere++; var = ap_getword(cmd->pool, &feature, '='); if (*feature) { apr_table_setn(new->features, var, feature); } else if (*var == '!') { apr_table_setn(new->features, var + 1, "!"); } else { apr_table_setn(new->features, var, "1"); } } if (!beenhere) { return apr_pstrcat(cmd->pool, "Missing envariable expression for ", cmd->cmd->name, NULL); } return NULL; } static const char *add_setenvif(cmd_parms *cmd, void *mconfig, const char *args) { char *fname; /* get header name */ fname = ap_getword_conf(cmd->pool, &args); if (!*fname) { return apr_pstrcat(cmd->pool, "Missing header-field name for ", cmd->cmd->name, NULL); } return add_setenvif_core(cmd, mconfig, fname, args); } /* * This routine handles the BrowserMatch* directives. It simply turns around * and feeds them, with the appropriate embellishments, to the general-purpose * command handler. */ static const char *add_browser(cmd_parms *cmd, void *mconfig, const char *args) { return add_setenvif_core(cmd, mconfig, "User-Agent", args); } static const command_rec setenvif_module_cmds[] = { AP_INIT_RAW_ARGS("SetEnvIf", add_setenvif, NULL, OR_FILEINFO, "A header-name, regex and a list of variables."), AP_INIT_RAW_ARGS("SetEnvIfNoCase", add_setenvif, ICASE_MAGIC, OR_FILEINFO, "a header-name, regex and a list of variables."), AP_INIT_RAW_ARGS("BrowserMatch", add_browser, NULL, OR_FILEINFO, "A browser regex and a list of variables."), AP_INIT_RAW_ARGS("BrowserMatchNoCase", add_browser, ICASE_MAGIC, OR_FILEINFO, "A browser regex and a list of variables."), { NULL }, }; /* * This routine gets called at two different points in request processing: * once before the URI has been translated (during the post-read-request * phase) and once after (during the header-parse phase). We use different * config records for the two different calls to reduce overhead (by not * re-doing the server-wide settings during directory processing), and * signal which call it is by having the earlier one pass a flag to the * later one. */ static int match_headers(request_rec *r) { sei_cfg_rec *sconf; sei_entry *entries; const apr_table_entry_t *elts; const char *val; apr_size_t val_len = 0; int i, j; char *last_name; ap_regmatch_t regm[AP_MAX_REG_MATCH]; if (!ap_get_module_config(r->request_config, &setenvif_module)) { ap_set_module_config(r->request_config, &setenvif_module, SEI_MAGIC_HEIRLOOM); sconf = (sei_cfg_rec *) ap_get_module_config(r->server->module_config, &setenvif_module); } else { sconf = (sei_cfg_rec *) ap_get_module_config(r->per_dir_config, &setenvif_module); } entries = (sei_entry *) sconf->conditionals->elts; last_name = NULL; val = NULL; for (i = 0; i < sconf->conditionals->nelts; ++i) { sei_entry *b = &entries[i]; /* Optimize the case where a bunch of directives in a row use the * same header. Remember we don't need to strcmp the two header * names because we made sure the pointers were equal during * configuration. */ if (b->name != last_name) { last_name = b->name; switch (b->special_type) { case SPECIAL_REMOTE_ADDR: val = r->connection->remote_ip; break; case SPECIAL_SERVER_ADDR: val = r->connection->local_ip; break; case SPECIAL_REMOTE_HOST: val = ap_get_remote_host(r->connection, r->per_dir_config, REMOTE_NAME, NULL); break; case SPECIAL_REQUEST_URI: val = r->uri; break; case SPECIAL_REQUEST_METHOD: val = r->method; break; case SPECIAL_REQUEST_PROTOCOL: val = r->protocol; break; case SPECIAL_NOT: if (b->pnamereg) { /* Matching headers_in against a regex. Iterate through * the headers_in until we find a match or run out of * headers. */ const apr_array_header_t *arr = apr_table_elts(r->headers_in); elts = (const apr_table_entry_t *) arr->elts; val = NULL; for (j = 0; j < arr->nelts; ++j) { if (!ap_regexec(b->pnamereg, elts[j].key, 0, NULL, 0)) { val = elts[j].val; } } } else { /* Not matching against a regex */ val = apr_table_get(r->headers_in, b->name); if (val == NULL) { val = apr_table_get(r->subprocess_env, b->name); } } } val_len = val ? strlen(val) : 0; } /* * A NULL value indicates that the header field or special entity * wasn't present or is undefined. Represent that as an empty string * so that REs like "^$" will work and allow envariable setting * based on missing or empty field. */ if (val == NULL) { val = ""; val_len = 0; } if ((b->pattern && apr_strmatch(b->pattern, val, val_len)) || (!b->pattern && !ap_regexec(b->preg, val, AP_MAX_REG_MATCH, regm, 0))) { const apr_array_header_t *arr = apr_table_elts(b->features); elts = (const apr_table_entry_t *) arr->elts; for (j = 0; j < arr->nelts; ++j) { if (*(elts[j].val) == '!') { apr_table_unset(r->subprocess_env, elts[j].key); } else { if (!b->pattern) { char *replaced = ap_pregsub(r->pool, elts[j].val, val, AP_MAX_REG_MATCH, regm); if (replaced) { apr_table_setn(r->subprocess_env, elts[j].key, replaced); } } else { apr_table_setn(r->subprocess_env, elts[j].key, elts[j].val); } } } } } return DECLINED; } static void register_hooks(apr_pool_t *p) { ap_hook_header_parser(match_headers, NULL, NULL, APR_HOOK_MIDDLE); ap_hook_post_read_request(match_headers, NULL, NULL, APR_HOOK_MIDDLE); } module AP_MODULE_DECLARE_DATA setenvif_module = { STANDARD20_MODULE_STUFF, create_setenvif_config_dir, /* dir config creater */ merge_setenvif_config, /* dir merger --- default is to override */ create_setenvif_config_svr, /* server config */ merge_setenvif_config, /* merge server configs */ setenvif_module_cmds, /* command apr_table_t */ register_hooks /* register hooks */ };
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