postlicyd/strlist.c

   1 /******************************************************************************/
   2 /*          pfixtools: a collection of postfix related tools                  */
   3 /*          ~~~~~~~~~                                                         */
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  17 /*     permission.                                                            */
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  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     */
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  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                     array_add(config->tries, trie);
 223                     array_add(config->weights, weight);
 224                     array_add(config->reverses, reverse);
 225                     break;
 226                 }
 227                 if (i != 3) {
 228                     current = p + 1;
 229                     p = m_strchrnul(current, ':');
 230                 }
 231             }
 232           } break;
 233
 234           /* hard_threshold parameter is an integer.
 235            *  If the matching score is greater or equal than this threshold,
 236            *  the hook "hard_match" is called.
 237            * hard_threshold = 1 means, that all matches are hard matches.
 238            * default is 1;
 239            */
 240           FILTER_PARAM_PARSE_INT(HARD_THRESHOLD, config->hard_threshold);
 241
 242           /* soft_threshold parameter is an integer.
 243            *  if the matching score is greater or equal than this threshold
 244            *  and smaller or equal than the hard_threshold, the hook "soft_match"
 245            *  is called.
 246            * default is 1;
 247            */
 248           FILTER_PARAM_PARSE_INT(SOFT_THRESHOLD, config->soft_threshold);
 249
 250           /* fields to match againes:
 251            *  fields = field_name(,field_name)*
 252            *  field_names are
 253            *    - hostname: helo_name,client_name,reverse_client_name
 254            *    - email: sender,recipient
 255            */
 256           case ATK_FIELDS: {
 257             const char *current = param->value;
 258             const char *p = m_strchrnul(param->value, ',');
 259             do {
 260                 postlicyd_token tok = policy_tokenize(current, p - current);
 261                 switch (tok) {
 262 #define           CASE(Up, Low, Type)                                          \
 263                   case PTK_ ## Up:                                             \
 264                     config->match_ ## Low = true;                              \
 265                     config->is_ ## Type = true;                                \
 266                     break
 267                   CASE(HELO_NAME, helo, hostname);
 268                   CASE(CLIENT_NAME, client, hostname);
 269                   CASE(REVERSE_CLIENT_NAME, reverse, hostname);
 270                   CASE(SENDER, sender, email);
 271                   CASE(RECIPIENT, recipient, email);
 272 #undef CASE
 273                   default:
 274                     PARSE_CHECK(false, "unknown field %.*s", p - current, current);
 275                     break;
 276                 }
 277                 if (!*p) {
 278                     break;
 279                 }
 280                 current = p + 1;
 281                 p = m_strchrnul(current, ',');
 282             } while (true);
 283           } break;
 284
 285           default: break;
 286         }
 287     }}
 288
 289     PARSE_CHECK(config->is_email != config->is_hostname,
 290                 "matched field MUST be emails XOR hostnames");
 291     PARSE_CHECK(config->tries.len,
 292                 "no file parameter in the filter %s", filter->name);
 293     filter->data = config;
 294     return true;
 295 }
 296
 297 static void strlist_filter_destructor(filter_t *filter)
 298 {
 299     strlist_config_t *config = filter->data;
 300     strlist_config_delete(&config);
 301     filter->data = config;
 302 }
 303
 304 static filter_result_t strlist_filter(const filter_t *filter, const query_t *query)
 305 {
 306     char reverse[BUFSIZ];
 307     char normal[BUFSIZ];
 308     const strlist_config_t *config = filter->data;
 309     int sum = 0;
 310     if (config->is_email &&
 311         ((config->match_sender && query->state < SMTP_MAIL)
 312         || (config->match_recipient && query->state != SMTP_RCPT))) {
 313         syslog(LOG_WARNING, "trying to match an email against a field that is not "
 314                "available in current protocol state");
 315         return HTK_ABORT;
 316     } else if (config->is_hostname && config->match_helo && query->state < SMTP_HELO) {
 317         syslog(LOG_WARNING, "trying to match hostname against helo before helo "
 318                "is received");
 319         return HTK_ABORT;
 320     }
 321 #define LOOKUP(Flag, Field)                                                    \
 322     if (config->match_ ## Flag) {                                              \
 323         const int len = m_strlen(query->Field);                                \
 324         strlist_copy(normal, query->Field, len, false);                        \
 325         strlist_copy(reverse, query->Field, len, true);                        \
 326         for (uint32_t i = 0 ; i < config->tries.len ; ++i) {                   \
 327             const int weight   = array_elt(config->weights, i);                \
 328             const trie_t *trie = array_elt(config->tries, i);                  \
 329             const bool rev = array_elt(config->reverses, i);                   \
 330             if (trie_lookup(trie, rev ? reverse : normal)) {                   \
 331                 sum += weight;                                                 \
 332             }                                                                  \
 333         }                                                                      \
 334     }
 335     if (config->is_email) {
 336         LOOKUP(sender, sender);
 337         LOOKUP(recipient, recipient);
 338     } else if (config->is_hostname) {
 339         LOOKUP(helo, helo_name);
 340         LOOKUP(client, client_name);
 341         LOOKUP(reverse, reverse_client_name);
 342     }
 343 #undef  LOOKUP
 344     if (sum >= config->hard_threshold) {
 345         return HTK_HARD_MATCH;
 346     } else if (sum >= config->soft_threshold) {
 347         return HTK_SOFT_MATCH;
 348     } else {
 349         return HTK_FAIL;
 350     }
 351 }
 352
 353 static int strlist_init(void)
 354 {
 355     filter_type_t type =  filter_register("strlist", strlist_filter_constructor,
 356                                           strlist_filter_destructor, strlist_filter);
 357     /* Hooks.
 358      */
 359     (void)filter_hook_register(type, "abort");
 360     (void)filter_hook_register(type, "error");
 361     (void)filter_hook_register(type, "fail");
 362     (void)filter_hook_register(type, "hard_match");
 363     (void)filter_hook_register(type, "soft_match");
 364
 365     /* Parameters.
 366      */
 367     (void)filter_param_register(type, "file");
 368     (void)filter_param_register(type, "hard_threshold");
 369     (void)filter_param_register(type, "soft_threshold");
 370     (void)filter_param_register(type, "fields");
 371     return 0;
 372 }
 373 module_init(strlist_init);