+enum smtp_state {
+ SMTP_UNKNOWN,
+ SMTP_CONNECT,
+ SMTP_EHLO,
+ SMTP_HELO = SMTP_EHLO,
+ SMTP_MAIL,
+ SMTP_RCPT,
+ SMTP_DATA,
+ SMTP_END_OF_MESSAGE,
+ SMTP_VRFY,
+ SMTP_ETRN,
+};
+
+/* \see http://www.postfix.org/SMTPD_POLICY_README.html */
+typedef struct query_t {
+ unsigned state : 4;
+ unsigned esmtp : 1;
+
+ const char *helo_name;
+ const char *queue_id;
+ const char *sender;
+ const char *recipient;
+ const char *recipient_count;
+ const char *client_address;
+ const char *client_name;
+ const char *rclient_name;
+ const char *instance;
+
+ /* postfix 2.2+ */
+ const char *sasl_method;
+ const char *sasl_username;
+ const char *sasl_sender;
+ const char *size;
+ const char *ccert_subject;
+ const char *ccert_issuer;
+ const char *ccsert_fingerprint;
+
+ /* postfix 2.3+ */
+ const char *encryption_protocol;
+ const char *encryption_cipher;
+ const char *encryption_keysize;
+ const char *etrn_domain;
+} query_t;
+
+static int postfix_parsejob(query_t *query, char *p)
+{
+#define PARSE_CHECK(expr, error, ...) \
+ do { \
+ if (!(expr)) { \
+ syslog(LOG_ERR, error, ##__VA_ARGS__); \
+ return -1; \
+ } \
+ } while (0)
+
+ p_clear(&query, 1);
+ while (p[0] != '\r' || p[1] != '\n') {
+ char *k, *v;
+ int klen, vlen, vtk;
+
+ while (isblank(*p))
+ p++;
+ p = strchr(k = p, '=');
+ PARSE_CHECK(p, "could not find '=' in line");
+ for (klen = p - k; klen && isblank(k[klen]); klen--);
+ p += 1; /* skip = */
+
+ while (isblank(*p))
+ p++;
+ p = strstr(v = p, "\r\n");
+ PARSE_CHECK(p, "could not find final \\r\\n in line");
+ for (vlen = p - v; vlen && isblank(v[vlen]); vlen--);
+ p += 2; /* skip \r\n */
+
+ vtk = tokenize(v, vlen);
+ switch (tokenize(k, klen)) {
+#define CASE(up, low) case PTK_##up: query->low = v; v[vlen] = '\0'; break;
+ CASE(HELO_NAME, helo_name);
+ CASE(QUEUE_ID, queue_id);
+ CASE(SENDER, sender);
+ CASE(RECIPIENT, recipient);
+ CASE(RECIPIENT_COUNT, recipient_count);
+ CASE(CLIENT_ADDRESS, client_address);
+ CASE(CLIENT_NAME, client_name);
+ CASE(RCLIENT_NAME, rclient_name);
+ CASE(INSTANCE, instance);
+ CASE(SASL_METHOD, sasl_method);
+ CASE(SASL_USERNAME, sasl_username);
+ CASE(SASL_SENDER, sasl_sender);
+ CASE(SIZE, size);
+ CASE(CCERT_SUBJECT, ccert_subject);
+ CASE(CCERT_ISSUER, ccert_issuer);
+ CASE(CCSERT_FINGERPRINT, ccsert_fingerprint);
+ CASE(ENCRYPTION_PROTOCOL, encryption_protocol);
+ CASE(ENCRYPTION_CIPHER, encryption_cipher);
+ CASE(ENCRYPTION_KEYSIZE, encryption_keysize);
+ CASE(ETRN_DOMAIN, etrn_domain);
+#undef CASE
+
+ case PTK_REQUEST:
+ PARSE_CHECK(vtk == PTK_SMTPD_ACCESS_POLICY,
+ "unexpected `request' value: %.*s", vlen, v);
+ break;
+
+ case PTK_PROTOCOL_NAME:
+ PARSE_CHECK(vtk == PTK_SMTP || vtk == PTK_ESMTP,
+ "unexpected `protocol_name' value: %.*s", vlen, v);
+ query->esmtp = vtk == PTK_ESMTP;
+ break;
+
+ case PTK_PROTOCOL_STATE:
+ switch (vtk) {
+#define CASE(name) case PTK_##name: query->state = SMTP_##name; break;
+ CASE(CONNECT);
+ CASE(EHLO);
+ CASE(HELO);
+ CASE(MAIL);
+ CASE(RCPT);
+ CASE(DATA);
+ CASE(END_OF_MESSAGE);
+ CASE(VRFY);
+ CASE(ETRN);
+ default:
+ PARSE_CHECK(false, "unexpected `protocol_state` value: %.*s",
+ vlen, v);
+#undef CASE
+ }
+ break;
+
+ default:
+ syslog(LOG_WARNING, "unexpected key, skipped: %.*s", klen, k);
+ break;
+ }
+ }
+
+ return query->state == SMTP_UNKNOWN ? -1 : 0;
+#undef PARSE_CHECK
+}
+
+static void *policy_run(int fd, void *data)
+{
+ buffer_t buf;
+
+ buffer_init(&buf);
+ for (;;) {
+ int nb = buffer_read(&buf, fd, -1);
+ const char *eoq;
+ query_t q;
+
+ if (nb < 0) {
+ if (errno == EAGAIN || errno == EINTR)
+ continue;
+ UNIXERR("read");
+ break;
+ }
+ if (nb == 0) {
+ if (buf.len)
+ syslog(LOG_ERR, "unexpected end of data");
+ break;
+ }
+
+ eoq = strstr(buf.data + MAX(0, buf.len - 3), "\r\n\r\n");
+ if (!eoq)
+ continue;
+
+ if (postfix_parsejob(&q, buf.data) < 0)
+ break;
+
+ buffer_consume(&buf, eoq + strlen("\r\n\r\n") - buf.data);
+ if (xwrite(fd, "DUNNO\r\n", strlen("DUNNO\r\n"))) {
+ UNIXERR("write");
+ break;
+ }
+ }
+ buffer_wipe(&buf);
+
+ close(fd);
+ return NULL;
+}
+