postlicyd/strlist.c

   1 /******************************************************************************/
   2 /*          pfixtools: a collection of postfix related tools                  */
   3 /*          ~~~~~~~~~                                                         */
   4 /*  ________________________________________________________________________  */
   5 /*                                                                            */
   6 /*  Redistribution and use in source and binary forms, with or without        */
   7 /*  modification, are permitted provided that the following conditions        */
   8 /*  are met:                                                                  */
   9 /*                                                                            */
  10 /*  1. Redistributions of source code must retain the above copyright         */
  11 /*     notice, this list of conditions and the following disclaimer.          */
  12 /*  2. Redistributions in binary form must reproduce the above copyright      */
  13 /*     notice, this list of conditions and the following disclaimer in the    */
  14 /*     documentation and/or other materials provided with the distribution.   */
  15 /*  3. The names of its contributors may not be used to endorse or promote    */
  16 /*     products derived from this software without specific prior written     */
  17 /*     permission.                                                            */
  18 /*                                                                            */
  19 /*  THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND   */
  20 /*  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE     */
  21 /*  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR        */
  22 /*  PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS    */
  23 /*  BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR    */
  24 /*  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF      */
  25 /*  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS  */
  26 /*  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN   */
  27 /*  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)   */
  28 /*  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF    */
  29 /*  THE POSSIBILITY OF SUCH DAMAGE.                                           */
  30 /******************************************************************************/
  31
  32 /*
  33  * Copyright © 2008 Florent Bruneau
  34  */
  35
  36 #include "filter.h"
  37 #include "trie.h"
  38 #include "file.h"
  39 #include "str.h"
  40 #include "policy_tokens.h"
  41
  42 typedef struct strlist_config_t {
  43     PA(trie_t) tries;
  44     A(int)     weights;
  45     A(bool)    reverses;
  46
  47     int soft_threshold;
  48     int hard_threshold;
  49
  50     unsigned is_email         :1;
  51     unsigned match_sender     :1;
  52     unsigned match_recipient  :1;
  53
  54     unsigned is_hostname      :1;
  55     unsigned match_helo       :1;
  56     unsigned match_client     :1;
  57     unsigned match_reverse    :1;
  58 } strlist_config_t;
  59
  60
  61 static strlist_config_t *strlist_config_new(void)
  62 {
  63     return p_new(strlist_config_t, 1);
  64 }
  65
  66 static void strlist_config_delete(strlist_config_t **config)
  67 {
  68     if (*config) {
  69         array_deep_wipe((*config)->tries, trie_delete);
  70         array_wipe((*config)->weights);
  71         array_wipe((*config)->reverses);
  72         p_delete(config);
  73     }
  74 }
  75
  76 static inline void strlist_copy(char *dest, const char *str, ssize_t str_len,
  77                                 bool reverse)
  78 {
  79     if (str_len > 0) {
  80         if (reverse) {
  81             for (const char *src = str + str_len - 1 ; src >= str ; --src) {
  82                 *dest = ascii_tolower(*src);
  83                 ++dest;
  84             }
  85         } else {
  86             for (int i = 0 ; i < str_len ; ++i) {
  87                 *dest = ascii_tolower(str[i]);
  88                 ++dest;
  89             }
  90         }
  91     }
  92     *dest = '\0';
  93 }
  94
  95
  96 static trie_t *strlist_create(const char *file, bool reverse, bool lock)
  97 {
  98     trie_t *db;
  99     file_map_t map;
 100     const char *p, *end;
 101     char line[BUFSIZ];
 102
 103     if (!file_map_open(&map, file, false)) {
 104         return NULL;
 105     }
 106     p   = map.map;
 107     end = map.end;
 108     while (end > p && end[-1] != '\n') {
 109         --end;
 110     }
 111     if (end != map.end) {
 112         syslog(LOG_WARNING, "file %s miss a final \\n, ignoring last line",
 113                file);
 114     }
 115
 116     db = trie_new();
 117     while (p < end && p != NULL) {
 118         const char *eol = (char *)memchr(p, '\n', end - p);
 119         if (eol == NULL) {
 120             eol = end;
 121         }
 122         if (eol - p >= BUFSIZ) {
 123             syslog(LOG_ERR, "unreasonnable long line");
 124             file_map_close(&map);
 125             trie_delete(&db);
 126             return NULL;
 127         }
 128         if (*p != '#') {
 129             const char *eos = eol;
 130             while (p < eos && isspace(*p)) {
 131                 ++p;
 132             }
 133             while (p < eos && isspace(eos[-1])) {
 134                 --eos;
 135             }
 136             if (p < eos) {
 137                 strlist_copy(line, p, eos - p, reverse);
 138                 trie_insert(db, line);
 139             }
 140         }
 141         p = eol + 1;
 142     }
 143     file_map_close(&map);
 144     trie_compile(db, lock);
 145     return db;
 146 }
 147
 148
 149 static bool strlist_filter_constructor(filter_t *filter)
 150 {
 151     strlist_config_t *config = strlist_config_new();
 152
 153 #define PARSE_CHECK(Expr, Str, ...)                                            \
 154     if (!(Expr)) {                                                             \
 155         syslog(LOG_ERR, Str, ##__VA_ARGS__);                                   \
 156         strlist_config_delete(&config);                                        \
 157         return false;                                                          \
 158     }
 159
 160     config->hard_threshold = 1;
 161     config->soft_threshold = 1;
 162     foreach (filter_param_t *param, filter->params) {
 163         switch (param->type) {
 164           /* file parameter is:
 165            *  [no]lock:(prefix|suffix):weight:filename
 166            *  valid options are:
 167            *    - lock:   memlock the database in memory.
 168            *    - nolock: don't memlock the database in memory.
 169            *    - prefix: perform "prefix" compression on storage.
 170            *    - suffix  perform "suffix" compression on storage.
 171            *    - \d+:    a number describing the weight to give to the match
 172            *              the given list [mandatory]
 173            *  the file pointed by filename MUST be a valid string list (one string per
 174            *  line, empty lines and lines beginning with a '#' are ignored).
 175            */
 176           case ATK_FILE: {
 177             bool lock = false;
 178             int  weight = 0;
 179             bool reverse = false;
 180             trie_t *trie = NULL;
 181             const char *current = param->value;
 182             const char *p = m_strchrnul(param->value, ':');
 183             char *next = NULL;
 184             for (int i = 0 ; i < 4 ; ++i) {
 185                 PARSE_CHECK(i == 3 || *p,
 186                             "file parameter must contains a locking state "
 187                             "and a weight option");
 188                 switch (i) {
 189                   case 0:
 190                     if ((p - current) == 4 && strncmp(current, "lock", 4) == 0) {
 191                         lock = true;
 192                     } else if ((p - current) == 6 && strncmp(current, "nolock", 6) == 0) {
 193                         lock = false;
 194                     } else {
 195                         PARSE_CHECK(false, "illegal locking state %.*s",
 196                                     p - current, current);
 197                     }
 198                     break;
 199
 200                   case 1:
 201                     if ((p - current) == 6 && strncmp(current, "suffix", 6) == 0) {
 202                         reverse = true;
 203                     } else if ((p - current) == 6 && strncmp(current, "prefix", 6) == 0) {
 204                         reverse = false;
 205                     } else {
 206                         PARSE_CHECK(false, "illegal character order value %.*s",
 207                                     p - current, current);
 208                     }
 209                     break;
 210
 211                   case 2:
 212                     weight = strtol(current, &next, 10);
 213                     PARSE_CHECK(next == p && weight >= 0 && weight <= 1024,
 214                                 "illegal weight value %.*s",
 215                                 (p - current), current);
 216                     break;
 217
 218                   case 3:
 219                     trie = strlist_create(current, reverse, lock);
 220                     PARSE_CHECK(trie != NULL,
 221                                 "cannot load string list from %s", current);
 222                     trie_inspect(trie, false);
 223                     array_add(config->tries, trie);
 224                     array_add(config->weights, weight);
 225                     array_add(config->reverses, reverse);
 226                     break;
 227                 }
 228                 if (i != 3) {
 229                     current = p + 1;
 230                     p = m_strchrnul(current, ':');
 231                 }
 232             }
 233           } break;
 234
 235           /* hard_threshold parameter is an integer.
 236            *  If the matching score is greater or equal than this threshold,
 237            *  the hook "hard_match" is called.
 238            * hard_threshold = 1 means, that all matches are hard matches.
 239            * default is 1;
 240            */
 241           FILTER_PARAM_PARSE_INT(HARD_THRESHOLD, config->hard_threshold);
 242
 243           /* soft_threshold parameter is an integer.
 244            *  if the matching score is greater or equal than this threshold
 245            *  and smaller or equal than the hard_threshold, the hook "soft_match"
 246            *  is called.
 247            * default is 1;
 248            */
 249           FILTER_PARAM_PARSE_INT(SOFT_THRESHOLD, config->soft_threshold);
 250
 251           /* fields to match againes:
 252            *  fields = field_name(,field_name)*
 253            *  field_names are
 254            *    - hostname: helo_name,client_name,reverse_client_name
 255            *    - email: sender,recipient
 256            */
 257           case ATK_FIELDS: {
 258             const char *current = param->value;
 259             const char *p = m_strchrnul(param->value, ',');
 260             do {
 261                 postlicyd_token tok = policy_tokenize(current, p - current);
 262                 switch (tok) {
 263 #define           CASE(Up, Low, Type)                                          \
 264                   case PTK_ ## Up:                                             \
 265                     config->match_ ## Low = true;                              \
 266                     config->is_ ## Type = true;                                \
 267                     break
 268                   CASE(HELO_NAME, helo, hostname);
 269                   CASE(CLIENT_NAME, client, hostname);
 270                   CASE(REVERSE_CLIENT_NAME, reverse, hostname);
 271                   CASE(SENDER, sender, email);
 272                   CASE(RECIPIENT, recipient, email);
 273 #undef CASE
 274                   default:
 275                     PARSE_CHECK(false, "unknown field %.*s", p - current, current);
 276                     break;
 277                 }
 278                 if (!*p) {
 279                     break;
 280                 }
 281                 current = p + 1;
 282                 p = m_strchrnul(current, ',');
 283             } while (true);
 284           } break;
 285
 286           default: break;
 287         }
 288     }}
 289
 290     PARSE_CHECK(config->is_email != config->is_hostname,
 291                 "matched field MUST be emails XOR hostnames");
 292     PARSE_CHECK(config->tries.len,
 293                 "no file parameter in the filter %s", filter->name);
 294     filter->data = config;
 295     return true;
 296 }
 297
 298 static void strlist_filter_destructor(filter_t *filter)
 299 {
 300     strlist_config_t *config = filter->data;
 301     strlist_config_delete(&config);
 302     filter->data = config;
 303 }
 304
 305 static filter_result_t strlist_filter(const filter_t *filter, const query_t *query)
 306 {
 307     char reverse[BUFSIZ];
 308     char normal[BUFSIZ];
 309     const strlist_config_t *config = filter->data;
 310     int sum = 0;
 311     if (config->is_email &&
 312         ((config->match_sender && query->state < SMTP_MAIL)
 313         || (config->match_recipient && query->state != SMTP_RCPT))) {
 314         syslog(LOG_WARNING, "trying to match an email against a field that is not "
 315                "available in current protocol state");
 316         return HTK_ABORT;
 317     } else if (config->is_hostname && config->match_helo && query->state < SMTP_HELO) {
 318         syslog(LOG_WARNING, "trying to match hostname against helo before helo "
 319                "is received");
 320         return HTK_ABORT;
 321     }
 322 #define LOOKUP(Flag, Field)                                                    \
 323     if (config->match_ ## Flag) {                                          \
 324         const int len = m_strlen(query->Field);                            \
 325         strlist_copy(normal, query->Field, len, false);                    \
 326         strlist_copy(reverse, query->Field, len, true);                    \
 327         for (int i = 0 ; i < config->tries.len ; ++i) {                    \
 328             const int weight   = array_elt(config->weights, i);            \
 329             const trie_t *trie = array_elt(config->tries, i);              \
 330             const bool rev = array_elt(config->reverses, i);               \
 331             if (trie_lookup(trie, rev ? reverse : normal)) {               \
 332                 sum += weight;                                             \
 333             }                                                              \
 334         }                                                                  \
 335     }
 336     if (config->is_email) {
 337         LOOKUP(sender, sender);
 338         LOOKUP(recipient, recipient);
 339     } else if (config->is_hostname) {
 340         LOOKUP(helo, helo_name);
 341         LOOKUP(client, client_name);
 342         LOOKUP(reverse, reverse_client_name);
 343     }
 344 #undef  LOOKUP
 345     if (sum >= config->hard_threshold) {
 346         return HTK_HARD_MATCH;
 347     } else if (sum >= config->soft_threshold) {
 348         return HTK_SOFT_MATCH;
 349     } else {
 350         return HTK_FAIL;
 351     }
 352 }
 353
 354 static int strlist_init(void)
 355 {
 356     filter_type_t type =  filter_register("strlist", strlist_filter_constructor,
 357                                           strlist_filter_destructor, strlist_filter);
 358     /* Hooks.
 359      */
 360     (void)filter_hook_register(type, "abort");
 361     (void)filter_hook_register(type, "error");
 362     (void)filter_hook_register(type, "fail");
 363     (void)filter_hook_register(type, "hard_match");
 364     (void)filter_hook_register(type, "soft_match");
 365
 366     /* Parameters.
 367      */
 368     (void)filter_param_register(type, "file");
 369     (void)filter_param_register(type, "hard_threshold");
 370     (void)filter_param_register(type, "soft_threshold");
 371     (void)filter_param_register(type, "fields");
 372     return 0;
 373 }
 374 module_init(strlist_init);