src/mod_alias.c

   1 #include "first.h"
   2
   3 #include "base.h"
   4 #include "log.h"
   5 #include "buffer.h"
   6
   7 #include "plugin.h"
   8
   9 #include <stdlib.h>
  10 #include <string.h>
  11
  12 /* plugin config for all request/connections */
  13 typedef struct {
  14         array *alias;
  15 } plugin_config;
  16
  17 typedef struct {
  18         PLUGIN_DATA;
  19
  20         plugin_config **config_storage;
  21
  22         plugin_config conf;
  23 } plugin_data;
  24
  25 /* init the plugin data */
  26 INIT_FUNC(mod_alias_init) {
  27         plugin_data *p;
  28
  29         p = calloc(1, sizeof(*p));
  30
  31
  32
  33         return p;
  34 }
  35
  36 /* detroy the plugin data */
  37 FREE_FUNC(mod_alias_free) {
  38         plugin_data *p = p_d;
  39
  40         if (!p) return HANDLER_GO_ON;
  41
  42         if (p->config_storage) {
  43                 size_t i;
  44
  45                 for (i = 0; i < srv->config_context->used; i++) {
  46                         plugin_config *s = p->config_storage[i];
  47
  48                         if (NULL == s) continue;
  49
  50                         array_free(s->alias);
  51
  52                         free(s);
  53                 }
  54                 free(p->config_storage);
  55         }
  56
  57         free(p);
  58
  59         return HANDLER_GO_ON;
  60 }
  61
  62 /* handle plugin config and check values */
  63
  64 SETDEFAULTS_FUNC(mod_alias_set_defaults) {
  65         plugin_data *p = p_d;
  66         size_t i = 0;
  67
  68         config_values_t cv[] = {
  69                 { "alias.url",                  NULL, T_CONFIG_ARRAY, T_CONFIG_SCOPE_CONNECTION },       /* 0 */
  70                 { NULL,                         NULL, T_CONFIG_UNSET,  T_CONFIG_SCOPE_UNSET }
  71         };
  72
  73         if (!p) return HANDLER_ERROR;
  74
  75         p->config_storage = calloc(srv->config_context->used, sizeof(plugin_config *));
  76
  77         for (i = 0; i < srv->config_context->used; i++) {
  78                 data_config const* config = (data_config const*)srv->config_context->data[i];
  79                 plugin_config *s;
  80
  81                 s = calloc(1, sizeof(plugin_config));
  82                 s->alias = array_init();
  83                 cv[0].destination = s->alias;
  84
  85                 p->config_storage[i] = s;
  86
  87                 if (0 != config_insert_values_global(srv, config->value, cv, i == 0 ? T_CONFIG_SCOPE_SERVER : T_CONFIG_SCOPE_CONNECTION)) {
  88                         return HANDLER_ERROR;
  89                 }
  90
  91                 if (!array_is_kvstring(s->alias)) {
  92                         log_error_write(srv, __FILE__, __LINE__, "s",
  93                                         "unexpected value for alias.url; expected list of \"urlpath\" => \"filepath\"");
  94                         return HANDLER_ERROR;
  95                 }
  96
  97                 if (s->alias->used >= 2) {
  98                         const array *a = s->alias;
  99                         size_t j, k;
 100
 101                         for (j = 0; j < a->used; j ++) {
 102                                 const buffer *prefix = a->data[a->sorted[j]]->key;
 103                                 for (k = j + 1; k < a->used; k ++) {
 104                                         const buffer *key = a->data[a->sorted[k]]->key;
 105
 106                                         if (buffer_string_length(key) < buffer_string_length(prefix)) {
 107                                                 break;
 108                                         }
 109                                         if (memcmp(key->ptr, prefix->ptr, buffer_string_length(prefix)) != 0) {
 110                                                 break;
 111                                         }
 112                                         /* ok, they have same prefix. check position */
 113                                         if (a->sorted[j] < a->sorted[k]) {
 114                                                 log_error_write(srv, __FILE__, __LINE__, "SBSBS",
 115                                                         "url.alias: `", key, "' will never match as `", prefix, "' matched first");
 116                                                 return HANDLER_ERROR;
 117                                         }
 118                                 }
 119                         }
 120                 }
 121         }
 122
 123         return HANDLER_GO_ON;
 124 }
 125
 126 #define PATCH(x) \
 127         p->conf.x = s->x;
 128 static int mod_alias_patch_connection(server *srv, connection *con, plugin_data *p) {
 129         size_t i, j;
 130         plugin_config *s = p->config_storage[0];
 131
 132         PATCH(alias);
 133
 134         /* skip the first, the global context */
 135         for (i = 1; i < srv->config_context->used; i++) {
 136                 data_config *dc = (data_config *)srv->config_context->data[i];
 137                 s = p->config_storage[i];
 138
 139                 /* condition didn't match */
 140                 if (!config_check_cond(srv, con, dc)) continue;
 141
 142                 /* merge config */
 143                 for (j = 0; j < dc->value->used; j++) {
 144                         data_unset *du = dc->value->data[j];
 145
 146                         if (buffer_is_equal_string(du->key, CONST_STR_LEN("alias.url"))) {
 147                                 PATCH(alias);
 148                         }
 149                 }
 150         }
 151
 152         return 0;
 153 }
 154 #undef PATCH
 155
 156 PHYSICALPATH_FUNC(mod_alias_physical_handler) {
 157         plugin_data *p = p_d;
 158         char *uri_ptr;
 159         size_t uri_len = buffer_string_length(con->physical.path);
 160         size_t basedir_len, alias_len;
 161         data_string *ds;
 162
 163         if (0 == uri_len) return HANDLER_GO_ON;
 164
 165         mod_alias_patch_connection(srv, con, p);
 166
 167         /* do not include trailing slash on basedir */
 168         basedir_len = buffer_string_length(con->physical.basedir);
 169         if ('/' == con->physical.basedir->ptr[basedir_len-1]) --basedir_len;
 170         uri_len -= basedir_len;
 171         uri_ptr = con->physical.path->ptr + basedir_len;
 172
 173         ds = (!con->conf.force_lowercase_filenames)
 174            ? (data_string *)array_match_key_prefix_klen(p->conf.alias, uri_ptr, uri_len)
 175            : (data_string *)array_match_key_prefix_nc_klen(p->conf.alias, uri_ptr, uri_len);
 176         if (NULL == ds) { return HANDLER_GO_ON; }
 177
 178                         /* matched */
 179
 180                         /* check for path traversal in url-path following alias if key
 181                          * does not end in slash, but replacement value ends in slash */
 182                         alias_len = buffer_string_length(ds->key);
 183                         if (uri_ptr[alias_len] == '.') {
 184                                 char *s = uri_ptr + alias_len + 1;
 185                                 if (*s == '.') ++s;
 186                                 if (*s == '/' || *s == '\0') {
 187                                         size_t vlen = buffer_string_length(ds->value);
 188                                         if (0 != alias_len && ds->key->ptr[alias_len-1] != '/'
 189                                             && 0 != vlen && ds->value->ptr[vlen-1] == '/') {
 190                                                 con->http_status = 403;
 191                                                 return HANDLER_FINISHED;
 192                                         }
 193                                 }
 194                         }
 195
 196                         buffer_copy_buffer(con->physical.basedir, ds->value);
 197                         buffer_copy_buffer(srv->tmp_buf, ds->value);
 198                         buffer_append_string(srv->tmp_buf, uri_ptr + alias_len);
 199                         buffer_copy_buffer(con->physical.path, srv->tmp_buf);
 200
 201                         return HANDLER_GO_ON;
 202 }
 203
 204 /* this function is called at dlopen() time and inits the callbacks */
 205
 206 int mod_alias_plugin_init(plugin *p);
 207 int mod_alias_plugin_init(plugin *p) {
 208         p->version     = LIGHTTPD_VERSION_ID;
 209         p->name        = buffer_init_string("alias");
 210
 211         p->init           = mod_alias_init;
 212         p->handle_physical= mod_alias_physical_handler;
 213         p->set_defaults   = mod_alias_set_defaults;
 214         p->cleanup        = mod_alias_free;
 215
 216         p->data        = NULL;
 217
 218         return 0;
 219 }