apache/modules/session/mod_session_cookie.c

   1 /* Licensed to the Apache Software Foundation (ASF) under one or more
   2  * contributor license agreements.  See the NOTICE file distributed with
   3  * this work for additional information regarding copyright ownership.
   4  * The ASF licenses this file to You under the Apache License, Version 2.0
   5  * (the "License"); you may not use this file except in compliance with
   6  * the License.  You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include "mod_session.h"
  18 #include "apr_lib.h"
  19 #include "apr_strings.h"
  20 #include "http_log.h"
  21 #include "util_cookies.h"
  22
  23 #define LOG_PREFIX "mod_session_cookie: "
  24 #define MOD_SESSION_COOKIE "mod_session_cookie"
  25
  26 module AP_MODULE_DECLARE_DATA session_cookie_module;
  27
  28 /**
  29  * Structure to carry the per-dir session config.
  30  */
  31 typedef struct {
  32     const char *name;
  33     int name_set;
  34     const char *name_attrs;
  35     const char *name2;
  36     int name2_set;
  37     const char *name2_attrs;
  38     int remove;
  39     int remove_set;
  40 } session_cookie_dir_conf;
  41
  42 /**
  43  * Set the cookie and embed the session within it.
  44  *
  45  * This function adds an RFC2109 compliant Set-Cookie header for
  46  * the cookie specified in SessionCookieName, and an RFC2965 compliant
  47  * Set-Cookie2 header for the cookie specified in SessionCookieName2.
  48  *
  49  * If specified, the optional cookie attributes will be added to
  50  * each cookie. If defaults are not specified, DEFAULT_ATTRS
  51  * will be used.
  52  *
  53  * On success, this method will return APR_SUCCESS.
  54  *
  55  * @param r The request pointer.
  56  * @param z A pointer to where the session will be written.
  57  */
  58 static int session_cookie_save(request_rec * r, session_rec * z)
  59 {
  60
  61     session_cookie_dir_conf *conf = ap_get_module_config(r->per_dir_config,
  62                                                     &session_cookie_module);
  63
  64     /* don't cache auth protected pages */
  65     apr_table_addn(r->headers_out, "Cache-Control", "no-cache");
  66
  67     /* create RFC2109 compliant cookie */
  68     if (conf->name_set) {
  69         if (z->encoded && z->encoded[0]) {
  70             ap_cookie_write(r, conf->name, z->encoded, conf->name_attrs, z->maxage, r->headers_out, r->err_headers_out, NULL);
  71         }
  72         else {
  73             ap_cookie_remove(r, conf->name, conf->name_attrs, r->headers_out, r->err_headers_out, NULL);
  74         }
  75     }
  76
  77     /* create RFC2965 compliant cookie */
  78     if (conf->name2_set) {
  79         if (z->encoded && z->encoded[0]) {
  80             ap_cookie_write2(r, conf->name2, z->encoded, conf->name2_attrs, z->maxage, r->headers_out, r->err_headers_out, NULL);
  81         }
  82         else {
  83             ap_cookie_remove2(r, conf->name2, conf->name2_attrs, r->headers_out, r->err_headers_out, NULL);
  84         }
  85     }
  86
  87     if (conf->name_set || conf->name2_set) {
  88         return OK;
  89     }
  90     return DECLINED;
  91
  92 }
  93
  94 /**
  95  * Isolate the cookie with the name "name", and if present, extract
  96  * the payload from the cookie.
  97  *
  98  * If the cookie is found, the cookie and any other cookies with the
  99  * same name are removed from the cookies passed in the request, so
 100  * that credentials are not leaked to a backend server or process.
 101  *
 102  * A missing or malformed cookie will cause this function to return
 103  * APR_EGENERAL.
 104  *
 105  * On success, this returns APR_SUCCESS.
 106  */
 107 static int session_cookie_load(request_rec * r, session_rec ** z)
 108 {
 109
 110     session_cookie_dir_conf *conf = ap_get_module_config(r->per_dir_config,
 111                                                     &session_cookie_module);
 112
 113     session_rec *zz = NULL;
 114     const char *val = NULL;
 115     const char *note = NULL;
 116     const char *name = NULL;
 117     request_rec *m = r;
 118
 119     /* find the first redirect */
 120     while (m->prev) {
 121         m = m->prev;
 122     }
 123     /* find the main request */
 124     while (m->main) {
 125         m = m->main;
 126     }
 127
 128     /* is our session in a cookie? */
 129     if (conf->name2_set) {
 130         name = conf->name2;
 131     }
 132     else if (conf->name_set) {
 133         name = conf->name;
 134     }
 135     else {
 136         return DECLINED;
 137     }
 138
 139     /* first look in the notes */
 140     note = apr_pstrcat(r->pool, MOD_SESSION_COOKIE, name, NULL);
 141     zz = (session_rec *)apr_table_get(m->notes, note);
 142     if (zz) {
 143         *z = zz;
 144         return OK;
 145     }
 146
 147     /* otherwise, try parse the cookie */
 148     ap_cookie_read(r, name, &val, conf->remove);
 149
 150     /* create a new session and return it */
 151     zz = (session_rec *) apr_pcalloc(r->pool, sizeof(session_rec));
 152     zz->pool = r->pool;
 153     zz->entries = apr_table_make(r->pool, 10);
 154     zz->encoded = val;
 155     zz->uuid = (apr_uuid_t *) apr_pcalloc(r->pool, sizeof(apr_uuid_t));
 156     *z = zz;
 157
 158     /* put the session in the notes so we don't have to parse it again */
 159     apr_table_setn(m->notes, note, (char *)zz);
 160
 161     return OK;
 162
 163 }
 164
 165
 166
 167 static void *create_session_cookie_dir_config(apr_pool_t * p, char *dummy)
 168 {
 169     session_cookie_dir_conf *new =
 170     (session_cookie_dir_conf *) apr_pcalloc(p, sizeof(session_cookie_dir_conf));
 171
 172     return (void *) new;
 173 }
 174
 175 static void *merge_session_cookie_dir_config(apr_pool_t * p, void *basev, void *addv)
 176 {
 177     session_cookie_dir_conf *new = (session_cookie_dir_conf *) apr_pcalloc(p, sizeof(session_cookie_dir_conf));
 178     session_cookie_dir_conf *add = (session_cookie_dir_conf *) addv;
 179     session_cookie_dir_conf *base = (session_cookie_dir_conf *) basev;
 180
 181     new->name = (add->name_set == 0) ? base->name : add->name;
 182     new->name_attrs = (add->name_set == 0) ? base->name_attrs : add->name_attrs;
 183     new->name_set = add->name_set || base->name_set;
 184     new->name2 = (add->name2_set == 0) ? base->name2 : add->name2;
 185     new->name2_attrs = (add->name2_set == 0) ? base->name2_attrs : add->name2_attrs;
 186     new->name2_set = add->name2_set || base->name2_set;
 187     new->remove = (add->remove_set == 0) ? base->remove : add->remove;
 188     new->remove_set = add->remove_set || base->remove_set;
 189
 190     return new;
 191 }
 192
 193 /**
 194  * Sanity check a given string that it exists, is not empty,
 195  * and does not contain special characters.
 196  */
 197 static const char *check_string(cmd_parms * cmd, const char *string)
 198 {
 199     if (!string || !*string || ap_strchr_c(string, '=') || ap_strchr_c(string, '&')) {
 200         return apr_pstrcat(cmd->pool, cmd->directive->directive,
 201                            " cannot be empty, or contain '=' or '&'.",
 202                            NULL);
 203     }
 204     return NULL;
 205 }
 206
 207 static const char *set_cookie_name(cmd_parms * cmd, void *config, const char *args)
 208 {
 209     char *last;
 210     char *line = apr_pstrdup(cmd->pool, args);
 211     session_cookie_dir_conf *conf = (session_cookie_dir_conf *) config;
 212     char *cookie = apr_strtok(line, " \t", &last);
 213     conf->name = cookie;
 214     conf->name_set = 1;
 215     while (apr_isspace(*last)) {
 216         last++;
 217     }
 218     conf->name_attrs = last;
 219     return check_string(cmd, cookie);
 220 }
 221
 222 static const char *set_cookie_name2(cmd_parms * cmd, void *config, const char *args)
 223 {
 224     char *last;
 225     char *line = apr_pstrdup(cmd->pool, args);
 226     session_cookie_dir_conf *conf = (session_cookie_dir_conf *) config;
 227     char *cookie = apr_strtok(line, " \t", &last);
 228     conf->name2 = cookie;
 229     conf->name2_set = 1;
 230     while (apr_isspace(*last)) {
 231         last++;
 232     }
 233     conf->name2_attrs = last;
 234     return check_string(cmd, cookie);
 235 }
 236
 237 static const char *
 238      set_remove(cmd_parms * parms, void *dconf, int flag)
 239 {
 240     session_cookie_dir_conf *conf = dconf;
 241
 242     conf->remove = flag;
 243     conf->remove_set = 1;
 244
 245     return NULL;
 246 }
 247
 248 static const command_rec session_cookie_cmds[] =
 249 {
 250     AP_INIT_RAW_ARGS("SessionCookieName", set_cookie_name, NULL, RSRC_CONF|OR_AUTHCFG,
 251                      "The name of the RFC2109 cookie carrying the session"),
 252     AP_INIT_RAW_ARGS("SessionCookieName2", set_cookie_name2, NULL, RSRC_CONF|OR_AUTHCFG,
 253                      "The name of the RFC2965 cookie carrying the session"),
 254     AP_INIT_FLAG("SessionCookieRemove", set_remove, NULL, RSRC_CONF|OR_AUTHCFG,
 255                  "Set to 'On' to remove the session cookie from the headers "
 256                  "and hide the cookie from a backend server or process"),
 257     {NULL}
 258 };
 259
 260 static void register_hooks(apr_pool_t * p)
 261 {
 262     ap_hook_session_load(session_cookie_load, NULL, NULL, APR_HOOK_MIDDLE);
 263     ap_hook_session_save(session_cookie_save, NULL, NULL, APR_HOOK_MIDDLE);
 264 }
 265
 266 module AP_MODULE_DECLARE_DATA session_cookie_module =
 267 {
 268     STANDARD20_MODULE_STUFF,
 269     create_session_cookie_dir_config, /* dir config creater */
 270     merge_session_cookie_dir_config,  /* dir merger --- default is to
 271                                        * override */
 272     NULL,                             /* server config */
 273     NULL,                             /* merge server config */
 274     session_cookie_cmds,              /* command apr_table_t */
 275     register_hooks                    /* register hooks */
 276 };