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/*
* Copyright 2015 Jan Pazdziora
*
* Licensed 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_core.h"
#include "http_config.h"
#include "http_log.h"
#include "http_request.h"
#include "ap_regex.h"
#include "apr_strings.h"
typedef struct {
const char * regexp_str;
ap_regex_t * regexp;
const char * substitution_str;
} auth_fixup_config_rec;
static void * create_dir_conf(apr_pool_t * pool, char * dir) {
auth_fixup_config_rec * cfg
= apr_pcalloc(pool, sizeof(auth_fixup_config_rec));
return cfg;
}
static const char * set_regexp(cmd_parms * cmd, void * struct_ptr,
const char * arg, const char * arg2) {
auth_fixup_config_rec * cfg = (auth_fixup_config_rec *) struct_ptr;
if (cfg) {
cfg->regexp = ap_pregcomp(cmd->pool, arg, AP_REG_EXTENDED);
if (cfg->regexp == NULL) {
return "Regular expression could not be compiled.";
}
cfg->regexp_str = apr_pstrdup(cmd->pool, arg);
if (arg2) {
cfg->substitution_str = apr_pstrdup(cmd->pool, arg2);
}
}
return NULL;
}
static const command_rec auth_fixup_cmds[] = {
AP_INIT_TAKE12("AuthFixupRegexp", set_regexp, NULL, OR_AUTHCFG,
"Regular expression to match against r->user, "
"and optional substitution string with backreferences"),
{NULL}
};
static int pretend_auth_type(request_rec *r) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, NULL, "pretend_auth_type: called with r->user [%s]", r->user);
const char *auth_type = ap_auth_type(r);
if (! auth_type || strcasecmp(auth_type, "Fixup")) {
return DECLINED;
}
if (r->user) {
return OK;
}
return DECLINED;
}
module AP_MODULE_DECLARE_DATA auth_fixup_module;
static int fixup_user(request_rec *r) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, NULL, "fixup_user: called with r->user [%s]", r->user);
if (apr_table_get(r->notes, "fixup-user-already-run")) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, NULL, "fixup_user: already run in this request, declining");
return DECLINED;
}
auth_fixup_config_rec *conf
= ap_get_module_config(r->per_dir_config, &auth_fixup_module);
if (pretend_auth_type(r) == OK) {
if (!r->user) {
ap_log_error(APLOG_MARK, APLOG_ERR, 0, NULL,
"fixup_user: AuthType Fixup configured and no r->user found, forbidden"
);
return HTTP_FORBIDDEN;
}
}
if (!r->user) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, NULL, "fixup_user: declining, no r->user");
return DECLINED;
}
apr_table_setn(r->notes, "fixup-user-already-run", r->user);
if (!conf->regexp) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, NULL, "fixup_user: declining, no conf->regexp");
return DECLINED;
}
unsigned int nmatch = AP_MAX_REG_MATCH;
ap_regmatch_t pmatch[AP_MAX_REG_MATCH];
if (ap_regexec(conf->regexp, r->user, nmatch, pmatch, 0)) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, NULL,
"fixup_user: matching [%s] =~ m/%s/ failed, forbidden",
r->user, conf->regexp_str);
return HTTP_FORBIDDEN;
}
char * new_user = ap_pregsub(r->pool,
( conf->substitution_str ? conf->substitution_str : "$0" ),
r->user, nmatch, pmatch);
if (! new_user) {
ap_log_error(APLOG_MARK, APLOG_ERR, 0, NULL,
"fixup_user: substitution [%s] =~ /%s/ -> [%s] failed, internal server error",
r->user, conf->regexp_str, conf->substitution_str);
return HTTP_INTERNAL_SERVER_ERROR;
}
if (! *new_user) {
ap_log_error(APLOG_MARK, APLOG_ERR, 0, NULL,
"fixup_user: substitution [%s] =~ /%s/ -> [%s] resulted in "
"empty string, forbidden",
r->user, conf->regexp_str, conf->substitution_str);
return HTTP_FORBIDDEN;
}
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, NULL,
"fixup_user: resetting user [%s] to [%s]", r->user, new_user);
r->user = new_user;
return DECLINED;
}
static void register_hooks(apr_pool_t * p) {
#if AP_MODULE_MAGIC_AT_LEAST(20111025,3)
static const char * const aszSucc[] = {"mod_authz_core.c",
"mod_lookup_identity.c", NULL};
static const char * const aszPred[] = {"mod_ssl.c", NULL};
ap_hook_check_access(fixup_user, aszPred, aszSucc, APR_HOOK_MIDDLE,
AP_AUTH_INTERNAL_PER_CONF);
ap_hook_check_authz(fixup_user, NULL, NULL, APR_HOOK_REALLY_FIRST,
AP_AUTH_INTERNAL_PER_CONF);
ap_hook_check_user_id(pretend_auth_type, NULL, NULL,
APR_HOOK_REALLY_FIRST);
#else
static const char * const aszSucc[] = {"mod_authn_default.c", NULL};
ap_hook_check_user_id(pretend_auth_type, NULL, aszSucc, APR_HOOK_LAST);
ap_hook_auth_checker(fixup_user, NULL, NULL, APR_HOOK_REALLY_FIRST);
#endif
}
module AP_MODULE_DECLARE_DATA auth_fixup_module = {
STANDARD20_MODULE_STUFF,
create_dir_conf, /* Per-directory configuration handler */
NULL, /* Merge handler for per-directory configurations */
NULL, /* Per-server configuration handler */
NULL, /* Merge handler for per-server configurations */
auth_fixup_cmds, /* Any directives we may have for httpd */
register_hooks /* Our hook registering function */
};
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