diff options
Diffstat (limited to 'modules/aaa/mod_authn_socache.c')
| -rw-r--r-- | modules/aaa/mod_authn_socache.c | 475 |
1 files changed, 475 insertions, 0 deletions
diff --git a/modules/aaa/mod_authn_socache.c b/modules/aaa/mod_authn_socache.c new file mode 100644 index 0000000..0e4454a --- /dev/null +++ b/modules/aaa/mod_authn_socache.c @@ -0,0 +1,475 @@ +/* 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 "apr_strings.h" +#include "apr_md5.h" /* for apr_password_validate */ + +#include "ap_config.h" +#include "ap_provider.h" +#include "httpd.h" +#include "http_config.h" +#include "http_core.h" +#include "http_log.h" +#include "http_protocol.h" +#include "http_request.h" + +#include "mod_auth.h" + +#include "ap_socache.h" +#include "util_mutex.h" +#include "apr_optional.h" + +module AP_MODULE_DECLARE_DATA authn_socache_module; + +typedef struct authn_cache_dircfg { + apr_interval_time_t timeout; + apr_array_header_t *providers; + const char *context; +} authn_cache_dircfg; + +/* FIXME: + * I think the cache and mutex should be global + */ +static apr_global_mutex_t *authn_cache_mutex = NULL; +static ap_socache_provider_t *socache_provider = NULL; +static ap_socache_instance_t *socache_instance = NULL; +static const char *const authn_cache_id = "authn-socache"; +static int configured; + +static apr_status_t remove_lock(void *data) +{ + if (authn_cache_mutex) { + apr_global_mutex_destroy(authn_cache_mutex); + authn_cache_mutex = NULL; + } + return APR_SUCCESS; +} + +static apr_status_t destroy_cache(void *data) +{ + if (socache_instance) { + socache_provider->destroy(socache_instance, (server_rec*)data); + socache_instance = NULL; + } + return APR_SUCCESS; +} + +static int authn_cache_precfg(apr_pool_t *pconf, apr_pool_t *plog, apr_pool_t *ptmp) +{ + apr_status_t rv = ap_mutex_register(pconf, authn_cache_id, + NULL, APR_LOCK_DEFAULT, 0); + if (rv != APR_SUCCESS) { + ap_log_perror(APLOG_MARK, APLOG_CRIT, rv, plog, APLOGNO(01673) + "failed to register %s mutex", authn_cache_id); + return 500; /* An HTTP status would be a misnomer! */ + } + socache_provider = ap_lookup_provider(AP_SOCACHE_PROVIDER_GROUP, + AP_SOCACHE_DEFAULT_PROVIDER, + AP_SOCACHE_PROVIDER_VERSION); + configured = 0; + return OK; +} + +static int authn_cache_post_config(apr_pool_t *pconf, apr_pool_t *plog, + apr_pool_t *ptmp, server_rec *s) +{ + apr_status_t rv; + static struct ap_socache_hints authn_cache_hints = {64, 32, 60000000}; + const char *errmsg; + + if (!configured) { + return OK; /* don't waste the overhead of creating mutex & cache */ + } + if (socache_provider == NULL) { + ap_log_perror(APLOG_MARK, APLOG_CRIT, 0, plog, APLOGNO(01674) + "Please select a socache provider with AuthnCacheSOCache " + "(no default found on this platform). Maybe you need to " + "load mod_socache_shmcb or another socache module first"); + return 500; /* An HTTP status would be a misnomer! */ + } + + /* We have socache_provider, but do not have socache_instance. This should + * happen only when using "default" socache_provider, so create default + * socache_instance in this case. */ + if (socache_instance == NULL) { + errmsg = socache_provider->create(&socache_instance, NULL, + ptmp, pconf); + if (errmsg) { + ap_log_perror(APLOG_MARK, APLOG_CRIT, 0, plog, APLOGNO(02612) + "failed to create mod_socache_shmcb socache " + "instance: %s", errmsg); + return 500; + } + } + + rv = ap_global_mutex_create(&authn_cache_mutex, NULL, + authn_cache_id, NULL, s, pconf, 0); + if (rv != APR_SUCCESS) { + ap_log_perror(APLOG_MARK, APLOG_CRIT, rv, plog, APLOGNO(01675) + "failed to create %s mutex", authn_cache_id); + return 500; /* An HTTP status would be a misnomer! */ + } + apr_pool_cleanup_register(pconf, NULL, remove_lock, apr_pool_cleanup_null); + + rv = socache_provider->init(socache_instance, authn_cache_id, + &authn_cache_hints, s, pconf); + if (rv != APR_SUCCESS) { + ap_log_perror(APLOG_MARK, APLOG_CRIT, rv, plog, APLOGNO(01677) + "failed to initialise %s cache", authn_cache_id); + return 500; /* An HTTP status would be a misnomer! */ + } + apr_pool_cleanup_register(pconf, (void*)s, destroy_cache, apr_pool_cleanup_null); + return OK; +} + +static void authn_cache_child_init(apr_pool_t *p, server_rec *s) +{ + const char *lock; + apr_status_t rv; + if (!configured) { + return; /* don't waste the overhead of creating mutex & cache */ + } + lock = apr_global_mutex_lockfile(authn_cache_mutex); + rv = apr_global_mutex_child_init(&authn_cache_mutex, lock, p); + if (rv != APR_SUCCESS) { + ap_log_error(APLOG_MARK, APLOG_CRIT, rv, s, APLOGNO(01678) + "failed to initialise mutex in child_init"); + } +} + +static const char *authn_cache_socache(cmd_parms *cmd, void *CFG, + const char *arg) +{ + const char *errmsg = ap_check_cmd_context(cmd, GLOBAL_ONLY); + const char *sep, *name; + + if (errmsg) + return errmsg; + + /* Argument is of form 'name:args' or just 'name'. */ + sep = ap_strchr_c(arg, ':'); + if (sep) { + name = apr_pstrmemdup(cmd->pool, arg, sep - arg); + sep++; + } + else { + name = arg; + } + + socache_provider = ap_lookup_provider(AP_SOCACHE_PROVIDER_GROUP, name, + AP_SOCACHE_PROVIDER_VERSION); + if (socache_provider == NULL) { + errmsg = apr_psprintf(cmd->pool, + "Unknown socache provider '%s'. Maybe you need " + "to load the appropriate socache module " + "(mod_socache_%s?)", arg, arg); + } + else { + errmsg = socache_provider->create(&socache_instance, sep, + cmd->temp_pool, cmd->pool); + } + + if (errmsg) { + errmsg = apr_psprintf(cmd->pool, "AuthnCacheSOCache: %s", errmsg); + } + return errmsg; +} + +static const char *authn_cache_enable(cmd_parms *cmd, void *CFG) +{ + const char *errmsg = ap_check_cmd_context(cmd, GLOBAL_ONLY); + configured = 1; + return errmsg; +} + +static const char *const directory = "directory"; +static void* authn_cache_dircfg_create(apr_pool_t *pool, char *s) +{ + authn_cache_dircfg *ret = apr_palloc(pool, sizeof(authn_cache_dircfg)); + ret->timeout = apr_time_from_sec(300); + ret->providers = NULL; + ret->context = directory; + return ret; +} + +/* not sure we want this. Might be safer to document use-all-or-none */ +static void* authn_cache_dircfg_merge(apr_pool_t *pool, void *BASE, void *ADD) +{ + authn_cache_dircfg *base = BASE; + authn_cache_dircfg *add = ADD; + authn_cache_dircfg *ret = apr_pmemdup(pool, add, sizeof(authn_cache_dircfg)); + /* preserve context and timeout if not defaults */ + if (add->context == directory) { + ret->context = base->context; + } + if (add->timeout == apr_time_from_sec(300)) { + ret->timeout = base->timeout; + } + if (add->providers == NULL) { + ret->providers = base->providers; + } + return ret; +} + +static const char *authn_cache_setprovider(cmd_parms *cmd, void *CFG, + const char *arg) +{ + authn_cache_dircfg *cfg = CFG; + if (cfg->providers == NULL) { + cfg->providers = apr_array_make(cmd->pool, 4, sizeof(const char*)); + } + APR_ARRAY_PUSH(cfg->providers, const char*) = arg; + configured = 1; + return NULL; +} + +static const char *authn_cache_timeout(cmd_parms *cmd, void *CFG, + const char *arg) +{ + authn_cache_dircfg *cfg = CFG; + int secs = atoi(arg); + cfg->timeout = apr_time_from_sec(secs); + return NULL; +} + +static const command_rec authn_cache_cmds[] = +{ + /* global stuff: cache and mutex */ + AP_INIT_TAKE1("AuthnCacheSOCache", authn_cache_socache, NULL, RSRC_CONF, + "socache provider for authn cache"), + AP_INIT_NO_ARGS("AuthnCacheEnable", authn_cache_enable, NULL, RSRC_CONF, + "enable socache configuration in htaccess even if not enabled anywhere else"), + /* per-dir stuff */ + AP_INIT_ITERATE("AuthnCacheProvideFor", authn_cache_setprovider, NULL, + OR_AUTHCFG, "Determine what authn providers to cache for"), + AP_INIT_TAKE1("AuthnCacheTimeout", authn_cache_timeout, NULL, + OR_AUTHCFG, "Timeout (secs) for cached credentials"), + AP_INIT_TAKE1("AuthnCacheContext", ap_set_string_slot, + (void*)APR_OFFSETOF(authn_cache_dircfg, context), + ACCESS_CONF, "Context for authn cache"), + {NULL} +}; + +static const char *construct_key(request_rec *r, const char *context, + const char *user, const char *realm) +{ + /* handle "special" context values */ + if (!strcmp(context, directory)) { + /* FIXME: are we at risk of this blowing up? */ + char *new_context; + char *slash = strrchr(r->uri, '/'); + new_context = apr_palloc(r->pool, slash - r->uri + + strlen(r->server->server_hostname) + 1); + strcpy(new_context, r->server->server_hostname); + strncat(new_context, r->uri, slash - r->uri); + context = new_context; + } + else if (!strcmp(context, "server")) { + context = r->server->server_hostname; + } + /* any other context value is literal */ + + if (realm == NULL) { /* basic auth */ + return apr_pstrcat(r->pool, context, ":", user, NULL); + } + else { /* digest auth */ + return apr_pstrcat(r->pool, context, ":", user, ":", realm, NULL); + } +} + +static void ap_authn_cache_store(request_rec *r, const char *module, + const char *user, const char *realm, + const char* data) +{ + apr_status_t rv; + authn_cache_dircfg *dcfg; + const char *key; + apr_time_t expiry; + + /* first check whether we're caching for this module */ + dcfg = ap_get_module_config(r->per_dir_config, &authn_socache_module); + if (!configured || !dcfg->providers) { + return; + } + if (!ap_array_str_contains(dcfg->providers, module)) { + return; + } + + /* OK, we're on. Grab mutex to do our business */ + rv = apr_global_mutex_trylock(authn_cache_mutex); + if (APR_STATUS_IS_EBUSY(rv)) { + /* don't wait around; just abandon it */ + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(01679) + "authn credentials for %s not cached (mutex busy)", user); + return; + } + else if (rv != APR_SUCCESS) { + ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01680) + "Failed to cache authn credentials for %s in %s", + module, dcfg->context); + return; + } + + /* We have the mutex, so go ahead */ + /* first build our key and determine expiry time */ + key = construct_key(r, dcfg->context, user, realm); + expiry = apr_time_now() + dcfg->timeout; + + /* store it */ + rv = socache_provider->store(socache_instance, r->server, + (unsigned char*)key, strlen(key), expiry, + (unsigned char*)data, strlen(data), r->pool); + if (rv == APR_SUCCESS) { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01681) + "Cached authn credentials for %s in %s", + user, dcfg->context); + } + else { + ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01682) + "Failed to cache authn credentials for %s in %s", + module, dcfg->context); + } + + /* We're done with the mutex */ + rv = apr_global_mutex_unlock(authn_cache_mutex); + if (rv != APR_SUCCESS) { + ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01683) "Failed to release mutex!"); + } +} + +#define MAX_VAL_LEN 256 +static authn_status check_password(request_rec *r, const char *user, + const char *password) +{ + /* construct key + * look it up + * if found, test password + * + * mutexing here would be a big performance drag. + * It's definitely unnecessary with some backends (like ndbm or gdbm) + * Is there a risk in the general case? I guess the only risk we + * care about is a race condition that gets us a dangling pointer + * to no-longer-defined memory. Hmmm ... + */ + apr_status_t rv; + const char *key; + authn_cache_dircfg *dcfg; + unsigned char val[MAX_VAL_LEN]; + unsigned int vallen = MAX_VAL_LEN - 1; + dcfg = ap_get_module_config(r->per_dir_config, &authn_socache_module); + if (!configured || !dcfg->providers) { + return AUTH_USER_NOT_FOUND; + } + key = construct_key(r, dcfg->context, user, NULL); + rv = socache_provider->retrieve(socache_instance, r->server, + (unsigned char*)key, strlen(key), + val, &vallen, r->pool); + + if (APR_STATUS_IS_NOTFOUND(rv)) { + /* not found - just return */ + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01684) + "Authn cache: no credentials found for %s", user); + return AUTH_USER_NOT_FOUND; + } + else if (rv == APR_SUCCESS) { + /* OK, we got a value */ + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01685) + "Authn cache: found credentials for %s", user); + val[vallen] = 0; + } + else { + /* error: give up and pass the buck */ + /* FIXME: getting this for NOTFOUND - prolly a bug in mod_socache */ + ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01686) + "Error accessing authentication cache"); + return AUTH_USER_NOT_FOUND; + } + + rv = apr_password_validate(password, (char*) val); + if (rv != APR_SUCCESS) { + return AUTH_DENIED; + } + + return AUTH_GRANTED; +} + +static authn_status get_realm_hash(request_rec *r, const char *user, + const char *realm, char **rethash) +{ + apr_status_t rv; + const char *key; + authn_cache_dircfg *dcfg; + unsigned char val[MAX_VAL_LEN]; + unsigned int vallen = MAX_VAL_LEN - 1; + dcfg = ap_get_module_config(r->per_dir_config, &authn_socache_module); + if (!configured || !dcfg->providers) { + return AUTH_USER_NOT_FOUND; + } + key = construct_key(r, dcfg->context, user, realm); + rv = socache_provider->retrieve(socache_instance, r->server, + (unsigned char*)key, strlen(key), + val, &vallen, r->pool); + + if (APR_STATUS_IS_NOTFOUND(rv)) { + /* not found - just return */ + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01687) + "Authn cache: no credentials found for %s", user); + return AUTH_USER_NOT_FOUND; + } + else if (rv == APR_SUCCESS) { + /* OK, we got a value */ + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01688) + "Authn cache: found credentials for %s", user); + } + else { + /* error: give up and pass the buck */ + /* FIXME: getting this for NOTFOUND - prolly a bug in mod_socache */ + ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01689) + "Error accessing authentication cache"); + return AUTH_USER_NOT_FOUND; + } + *rethash = apr_pstrmemdup(r->pool, (char *)val, vallen); + + return AUTH_USER_FOUND; +} + +static const authn_provider authn_cache_provider = +{ + &check_password, + &get_realm_hash, +}; + +static void register_hooks(apr_pool_t *p) +{ + ap_register_auth_provider(p, AUTHN_PROVIDER_GROUP, "socache", + AUTHN_PROVIDER_VERSION, + &authn_cache_provider, AP_AUTH_INTERNAL_PER_CONF); + APR_REGISTER_OPTIONAL_FN(ap_authn_cache_store); + ap_hook_pre_config(authn_cache_precfg, NULL, NULL, APR_HOOK_MIDDLE); + ap_hook_post_config(authn_cache_post_config, NULL, NULL, APR_HOOK_MIDDLE); + ap_hook_child_init(authn_cache_child_init, NULL, NULL, APR_HOOK_MIDDLE); +} + +AP_DECLARE_MODULE(authn_socache) = +{ + STANDARD20_MODULE_STUFF, + authn_cache_dircfg_create, + authn_cache_dircfg_merge, + NULL, + NULL, + authn_cache_cmds, + register_hooks +}; |