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+/* 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 "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 environment 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 */
+ ap_expr_info_t *expr; /* parsed expression */
+ 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 ap_regex_t *is_header_regex_regex;
+
+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.
+ */
+ if (ap_regexec(is_header_regex_regex, 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_envvars(cmd_parms *cmd, const char *args, sei_entry *new)
+{
+ const char *feature;
+ int beenhere = 0;
+ char *var;
+
+ 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_core(cmd_parms *cmd, void *mconfig,
+ char *fname, const char *args)
+{
+ char *regex;
+ const char *simple_pattern;
+ sei_cfg_rec *sconf;
+ sei_entry *new;
+ sei_entry *entries;
+ int i;
+ 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 (new->name && !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->temp_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];
+ }
+
+ return add_envvars(cmd, args, new);
+}
+
+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);
+}
+
+static const char *add_setenvifexpr(cmd_parms *cmd, void *mconfig,
+ const char *args)
+{
+ char *expr;
+ sei_cfg_rec *sconf;
+ sei_entry *new;
+ const char *err;
+
+ /*
+ * 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);
+ /* get expr */
+ expr = ap_getword_conf(cmd->pool, &args);
+ if (!*expr) {
+ return apr_pstrcat(cmd->pool, "Missing expression for ",
+ cmd->cmd->name, NULL);
+ }
+
+ new = apr_array_push(sconf->conditionals);
+ new->features = apr_table_make(cmd->pool, 2);
+ new->name = NULL;
+ new->regex = NULL;
+ new->pattern = NULL;
+ new->preg = NULL;
+ new->expr = ap_expr_parse_cmd(cmd, expr, 0, &err, NULL);
+ if (err)
+ return apr_psprintf(cmd->pool, "Could not parse expression \"%s\": %s",
+ expr, err);
+
+ return add_envvars(cmd, args, new);
+}
+
+/*
+ * 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("SetEnvIfExpr", add_setenvifexpr, NULL, OR_FILEINFO,
+ "an expression 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, *err;
+ 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];
+
+ if (!b->expr) {
+ /* 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->useragent_ip;
+ break;
+ case SPECIAL_SERVER_ADDR:
+ val = r->connection->local_ip;
+ break;
+ case SPECIAL_REMOTE_HOST:
+ val = ap_get_useragent_host(r, 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. This is also necessary to make
+ * ap_pregsub work after evaluating an ap_expr_t which does set the
+ * regexp backref data.
+ */
+ if (val == NULL) {
+ val = "";
+ val_len = 0;
+ }
+
+ if ((b->pattern && apr_strmatch(b->pattern, val, val_len)) ||
+ (b->preg && !ap_regexec(b->preg, val, AP_MAX_REG_MATCH, regm, 0)) ||
+ (b->expr && ap_expr_exec_re(r, b->expr, AP_MAX_REG_MATCH, regm, &val, &err) > 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 {
+ /*
+ * Do regex replacement, if we did not use a pattern, so
+ * either a regex or an expression and if we have a val
+ * or at least we did not use an expression.
+ * Background: We can have expressions that become true
+ * if a regex pattern in the expression does NOT match.
+ * In this case val is NULL and we should just set the
+ * value for the environment variable like in the pattern
+ * case.
+ */
+ if (!b->pattern && (val || !b->expr)) {
+ 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 {
+ ap_log_rerror(APLOG_MARK, APLOG_CRIT, 0, r, APLOGNO(01505)
+ "Regular expression replacement "
+ "failed for '%s', value too long?",
+ elts[j].key);
+ return HTTP_INTERNAL_SERVER_ERROR;
+ }
+ }
+ else {
+ apr_table_setn(r->subprocess_env, elts[j].key,
+ elts[j].val);
+ }
+ }
+ ap_log_rerror(APLOG_MARK, APLOG_TRACE2, 0, r, "Setting %s",
+ elts[j].key);
+ }
+ }
+ }
+
+ 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);
+
+ is_header_regex_regex = ap_pregcomp(p, "^[-A-Za-z0-9_]*$",
+ (AP_REG_EXTENDED | AP_REG_NOSUB ));
+ ap_assert(is_header_regex_regex != NULL);
+}
+
+AP_DECLARE_MODULE(setenvif) =
+{
+ 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 */
+};