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 = m_strnextsp(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 &&
 123                         (isspace(*n) || IS_OP_START(*n)),
 124                         "invalid condition, expected operator after field name");
 125             condition.field = policy_tokenize(p, n - p);
 126             PARSE_CHECK(condition.field >= PTK_HELO_NAME
 127                         && condition.field < PTK_SMTPD_ACCESS_POLICY,
 128                         "invalid field name %.*s", n - p, p);
 129             p = m_strnextsp(n);
 130             n = p + 1;
 131             PARSE_CHECK(IS_OP_START(*p) && IS_OP_END(*n),
 132                         "invalid operator %2s", p);
 133             switch (*p) {
 134 #define       CASE_OP(C, Value)                                                         \
 135               case C:                                                                   \
 136                 condition.condition = MATCH_ ## Value;                                  \
 137                 PARSE_CHECK(*n == '=' || *n == 'i', "invalid operator modifier %c", *n);\
 138                 condition.case_sensitive = !!(*n == '=');                               \
 139                 break;
 140               CASE_OP('=', EQUAL);
 141               CASE_OP('!', DIFFER);
 142               CASE_OP('>', CONTAINS);
 143               CASE_OP('<', CONTAINED);
 144               CASE_OP('#', EMPTY);
 145 #undef        CASE_OP
 146             }
 147             PARSE_CHECK(condition.condition != MATCH_UNKNOWN,
 148                         "invalid operator");
 149             if (condition.condition != MATCH_EMPTY) {
 150                 p = m_strnextsp(n + 1);
 151                 PARSE_CHECK(*p, "no value defined to check the condition");
 152                 condition.value_len = param->value_len - (p - param->value);
 153                 condition.value     = p_dupstr(p, condition.value_len);
 154             }
 155             array_add(config->conditions, condition);
 156           } break;
 157
 158           default: break;
 159         }
 160     }}
 161
 162     PARSE_CHECK(config->conditions.len > 0,
 163                 "no condition defined");
 164     filter->data = config;
 165     return true;
 166 }
 167
 168 static void match_filter_destructor(filter_t *filter)
 169 {
 170     match_config_t *config = filter->data;
 171     match_config_delete(&config);
 172     filter->data = config;
 173 }
 174
 175 static inline bool match_condition(const match_condition_t *cond, const query_t *query)
 176 {
 177     const char *field = NULL;
 178     switch (cond->field) {
 179 #define CASE(Up, Low)                                                          \
 180       case PTK_ ## Up: field = query->Low; break;
 181       CASE(HELO_NAME, helo_name)
 182       CASE(QUEUE_ID, queue_id)
 183       CASE(SENDER, sender)
 184       CASE(RECIPIENT, recipient)
 185       CASE(RECIPIENT_COUNT, recipient_count)
 186       CASE(CLIENT_ADDRESS, client_address)
 187       CASE(CLIENT_NAME, client_name)
 188       CASE(REVERSE_CLIENT_NAME, reverse_client_name)
 189       CASE(INSTANCE, instance)
 190       CASE(SASL_METHOD, sasl_method)
 191       CASE(SASL_USERNAME, sasl_username)
 192       CASE(SASL_SENDER, sasl_sender)
 193       CASE(SIZE, size)
 194       CASE(CCERT_SUBJECT, ccert_subject)
 195       CASE(CCERT_ISSUER, ccert_issuer)
 196       CASE(CCERT_FINGERPRINT, ccert_fingerprint)
 197       CASE(ENCRYPTION_PROTOCOL, encryption_protocol)
 198       CASE(ENCRYPTION_CIPHER, encryption_cipher)
 199       CASE(ENCRYPTION_KEYSIZE, encryption_keysize)
 200       CASE(ETRN_DOMAIN, etrn_domain)
 201       CASE(STRESS, stress)
 202 #undef CASE
 203       default: return false;
 204     }
 205     switch (cond->condition) {
 206       case MATCH_EQUAL:
 207       case MATCH_DIFFER:
 208         if (field == NULL) {
 209             return cond->condition != MATCH_DIFFER;
 210         }
 211         if (cond->case_sensitive) {
 212             return !!((strcmp(field, cond->value) == 0)
 213                       ^ (cond->condition == MATCH_DIFFER));
 214         } else {
 215             return !!((strcasecmp(field, cond->value) == 0)
 216                       ^ (cond->condition == MATCH_DIFFER));
 217         }
 218         break;
 219
 220       case MATCH_CONTAINS:
 221         if (field == NULL) {
 222             return false;
 223         }
 224         if (cond->case_sensitive) {
 225             return strstr(field, cond->value);
 226         } else {
 227             /* XXX: GNU Sources */
 228             return strcasestr(field, cond->value);
 229         }
 230         break;
 231
 232       case MATCH_CONTAINED:
 233         if (field == NULL) {
 234             return false;
 235         }
 236         if (cond->case_sensitive) {
 237             return strstr(cond->value, field);
 238         } else {
 239             /* XXX: GNU Sources */
 240             return strcasestr(cond->value, field);
 241         }
 242         break;
 243
 244       case MATCH_EMPTY:
 245         return !!(!!(field == NULL || *field == '\0')) ^ (!!cond->case_sensitive);
 246
 247       default:
 248         assert(false && "invalid condition type");
 249     }
 250     return true;
 251 }
 252
 253 static filter_result_t match_filter(const filter_t *filter, const query_t *query)
 254 {
 255     const match_config_t *config = filter->data;
 256     foreach (const match_condition_t *condition, config->conditions) {
 257         bool r = match_condition(condition, query);
 258         if (!r && config->match_all) {
 259             return HTK_FALSE;
 260         } else if (r && !(config->match_all)) {
 261             return HTK_TRUE;
 262         }
 263     }}
 264     if (config->match_all) {
 265         return HTK_TRUE;
 266     } else {
 267         return HTK_FALSE;
 268     }
 269 }
 270
 271 static int match_init(void)
 272 {
 273     filter_type_t type =  filter_register("match", match_filter_constructor,
 274                                           match_filter_destructor, match_filter);
 275     /* Hooks.
 276      */
 277     (void)filter_hook_register(type, "abort");
 278     (void)filter_hook_register(type, "error");
 279     (void)filter_hook_register(type, "true");
 280     (void)filter_hook_register(type, "false");
 281
 282     /* Parameters.
 283      */
 284     (void)filter_param_register(type, "match_all");
 285     (void)filter_param_register(type, "condition");
 286     return 0;
 287 }
 288 module_init(match_init);