postlicyd/match.c

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  30 /******************************************************************************/
  31
  32 /*
  33  * Copyright © 2008 Florent Bruneau
  34  */
  35
  36 #include "filter.h"
  37 #include "str.h"
  38 #include "policy_tokens.h"
  39
  40 typedef struct match_condition_t {
  41     postlicyd_token field;
  42     bool case_sensitive;
  43     enum {
  44         MATCH_UNKNOWN  = 0,
  45         MATCH_EQUAL,
  46         MATCH_DIFFER,
  47         MATCH_CONTAINS,
  48         MATCH_CONTAINED,
  49         MATCH_EMPTY,
  50     } condition;
  51
  52     char *value;
  53     ssize_t value_len;
  54 } match_condition_t;
  55 ARRAY(match_condition_t)
  56
  57 #define CONDITION_INIT { PTK_UNKNOWN, false, MATCH_UNKNOWN, NULL, 0 }
  58
  59 typedef struct match_config_t {
  60     A(match_condition_t) conditions;
  61     bool match_all;
  62 } match_config_t;
  63
  64 static match_config_t *match_config_new(void)
  65 {
  66     return p_new(match_config_t, 1);
  67 }
  68
  69 static inline void match_condition_wipe(match_condition_t *condition)
  70 {
  71     p_delete(&condition->value);
  72     condition->value_len = 0;
  73 }
  74
  75 static void match_config_delete(match_config_t **config)
  76 {
  77     if (*config) {
  78         array_deep_wipe((*config)->conditions, match_condition_wipe);
  79         p_delete(config);
  80     }
  81 }
  82
  83 static bool match_filter_constructor(filter_t *filter)
  84 {
  85     match_config_t *config = match_config_new();
  86
  87 #define PARSE_CHECK(Expr, Str, ...)                                            \
  88     if (!(Expr)) {                                                             \
  89         syslog(LOG_ERR, Str, ##__VA_ARGS__);                                   \
  90         match_config_delete(&config);                                        \
  91         return false;                                                          \
  92     }
  93
  94     foreach (filter_param_t *param, filter->params) {
  95         switch (param->type) {
  96           FILTER_PARAM_PARSE_BOOLEAN(MATCH_ALL, config->match_all);
  97
  98           /* condition parameter is:
  99            *  field_name OPERATOR value.
 100            *  valid operators are:
 101            *    == field_name is strictly equal to
 102            *    =i field_name is case insensitively equal to
 103            *    != field_name is not equal to
 104            *    !i field_name is not case insensitively equal to
 105            *    >= field_name contains
 106            *    >i field_name contains case insensitively
 107            *    <= field_name is contained
 108            *    <i field_name is contained case insensitively
 109            *    #= field_name is empty or not set
 110            *    #i field_name is not empty
 111            */
 112           case ATK_CONDITION: {
 113 #define     IS_OP_START(N)                                                        \
 114               ((N) == '=' || (N) == '!' || (N) == '>' || (N) == '<' || (N) == '#')
 115 #define     IS_OP_END(N)                                                          \
 116               ((N) == '=' || (N) == 'i')
 117             match_condition_t condition = CONDITION_INIT;
 118             const char *p = skipspaces(param->value);
 119             const char *n = p + 1;
 120             PARSE_CHECK(isalnum(*p), "invalid field name");
 121             for (n = p + 1 ; *n && (isalnum(*n) || *n == '_') ; ++n);
 122             PARSE_CHECK(*n && (isspace(*n) || IS_OP_START(*n)),
 123                         "invalid condition, expected operator after field name");
 124             condition.field = policy_tokenize(p, n - p);
 125             PARSE_CHECK(condition.field >= PTK_HELO_NAME
 126                         && condition.field < PTK_SMTPD_ACCESS_POLICY,
 127                         "invalid field name %.*s", n - p, p);
 128             p = skipspaces(n);
 129             n = p + 1;
 130             PARSE_CHECK(IS_OP_START(*p) && IS_OP_END(*n),
 131                         "invalid operator %2s", p);
 132             switch (*p) {
 133 #define       CASE_OP(C, Value)                                                         \
 134               case C:                                                                   \
 135                 condition.condition = MATCH_ ## Value;                                  \
 136                 PARSE_CHECK(*n == '=' || *n == 'i', "invalid operator modifier %c", *n);\
 137                 condition.case_sensitive = !!(*n == '=');                               \
 138                 break;
 139               CASE_OP('=', EQUAL);
 140               CASE_OP('!', DIFFER);
 141               CASE_OP('>', CONTAINS);
 142               CASE_OP('<', CONTAINED);
 143               CASE_OP('#', EMPTY);
 144 #undef        CASE_OP
 145             }
 146             PARSE_CHECK(condition.condition != MATCH_UNKNOWN,
 147                         "invalid operator");
 148             if (condition.condition != MATCH_EMPTY) {
 149                 p = m_strnextsp(n + 1);
 150                 PARSE_CHECK(*p, "no value defined to check the condition");
 151                 condition.value_len = param->value_len - (p - param->value);
 152                 condition.value     = p_dupstr(p, condition.value_len);
 153             }
 154             array_add(config->conditions, condition);
 155           } break;
 156
 157           default: break;
 158         }
 159     }}
 160
 161     PARSE_CHECK(config->conditions.len > 0,
 162                 "no condition defined");
 163     filter->data = config;
 164     return true;
 165 }
 166
 167 static void match_filter_destructor(filter_t *filter)
 168 {
 169     match_config_t *config = filter->data;
 170     match_config_delete(&config);
 171     filter->data = config;
 172 }
 173
 174 static inline bool match_condition(const match_condition_t *cond, const query_t *query)
 175 {
 176     const char *field = NULL;
 177     switch (cond->field) {
 178 #define CASE(Up, Low)                                                          \
 179       case PTK_ ## Up: field = query->Low; break;
 180       CASE(HELO_NAME, helo_name)
 181       CASE(QUEUE_ID, queue_id)
 182       CASE(SENDER, sender)
 183       CASE(RECIPIENT, recipient)
 184       CASE(RECIPIENT_COUNT, recipient_count)
 185       CASE(CLIENT_ADDRESS, client_address)
 186       CASE(CLIENT_NAME, client_name)
 187       CASE(REVERSE_CLIENT_NAME, reverse_client_name)
 188       CASE(INSTANCE, instance)
 189       CASE(SASL_METHOD, sasl_method)
 190       CASE(SASL_USERNAME, sasl_username)
 191       CASE(SASL_SENDER, sasl_sender)
 192       CASE(SIZE, size)
 193       CASE(CCERT_SUBJECT, ccert_subject)
 194       CASE(CCERT_ISSUER, ccert_issuer)
 195       CASE(CCERT_FINGERPRINT, ccert_fingerprint)
 196       CASE(ENCRYPTION_PROTOCOL, encryption_protocol)
 197       CASE(ENCRYPTION_CIPHER, encryption_cipher)
 198       CASE(ENCRYPTION_KEYSIZE, encryption_keysize)
 199       CASE(ETRN_DOMAIN, etrn_domain)
 200       CASE(STRESS, stress)
 201 #undef CASE
 202       default: return false;
 203     }
 204     switch (cond->condition) {
 205       case MATCH_EQUAL:
 206       case MATCH_DIFFER:
 207         if (field == NULL) {
 208             return cond->condition != MATCH_DIFFER;
 209         }
 210         if (cond->case_sensitive) {
 211             return !!((strcmp(field, cond->value) == 0)
 212                       ^ (cond->condition == MATCH_DIFFER));
 213         } else {
 214             return !!((ascii_strcasecmp(field, cond->value) == 0)
 215                       ^ (cond->condition == MATCH_DIFFER));
 216         }
 217         break;
 218
 219       case MATCH_CONTAINS:
 220         if (field == NULL) {
 221             return false;
 222         }
 223         if (cond->case_sensitive) {
 224             return strstr(field, cond->value);
 225         } else {
 226             return m_stristrn(field, cond->value, cond->value_len);
 227         }
 228         break;
 229
 230       case MATCH_CONTAINED:
 231         if (field == NULL) {
 232             return false;
 233         }
 234         if (cond->case_sensitive) {
 235             return strstr(cond->value, field);
 236         } else {
 237             return m_stristr(cond->value, field);
 238         }
 239         break;
 240
 241       case MATCH_EMPTY:
 242         return !!((field == NULL || *field == '\0') ^ (!cond->case_sensitive));
 243
 244       default:
 245         assert(false && "invalid condition type");
 246     }
 247     return true;
 248 }
 249
 250 static filter_result_t match_filter(const filter_t *filter, const query_t *query)
 251 {
 252     const match_config_t *config = filter->data;
 253     foreach (const match_condition_t *condition, config->conditions) {
 254         bool r = match_condition(condition, query);
 255         if (!r && config->match_all) {
 256             return HTK_FAIL;
 257         } else if (r && !(config->match_all)) {
 258             return HTK_MATCH;
 259         }
 260     }}
 261     if (config->match_all) {
 262         return HTK_MATCH;
 263     } else {
 264         return HTK_FAIL;
 265     }
 266 }
 267
 268 static int match_init(void)
 269 {
 270     filter_type_t type =  filter_register("match", match_filter_constructor,
 271                                           match_filter_destructor, match_filter);
 272     /* Hooks.
 273      */
 274     (void)filter_hook_register(type, "abort");
 275     (void)filter_hook_register(type, "error");
 276     (void)filter_hook_register(type, "match");
 277     (void)filter_hook_register(type, "fail");
 278
 279     /* Parameters.
 280      */
 281     (void)filter_param_register(type, "match_all");
 282     (void)filter_param_register(type, "condition");
 283     return 0;
 284 }
 285 module_init(match_init);