policy.c

   1 /******************************************************************************/
   2 /*          pfixtools: a collection of postfix related tools                  */
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  29 /*  THE POSSIBILITY OF SUCH DAMAGE.                                           */
  30 /******************************************************************************/
  31
  32 /*
  33  * Copyright © 2006-2007 Pierre Habouzit
  34  */
  35
  36 #include "common.h"
  37 #include "policy.h"
  38 #include "buffer.h"
  39 #include "tokens.h"
  40
  41 enum smtp_state {
  42     SMTP_UNKNOWN,
  43     SMTP_CONNECT,
  44     SMTP_EHLO,
  45     SMTP_HELO = SMTP_EHLO,
  46     SMTP_MAIL,
  47     SMTP_RCPT,
  48     SMTP_DATA,
  49     SMTP_END_OF_MESSAGE,
  50     SMTP_VRFY,
  51     SMTP_ETRN,
  52 };
  53
  54 /* \see http://www.postfix.org/SMTPD_POLICY_README.html */
  55 typedef struct query_t {
  56     unsigned state : 4;
  57     unsigned esmtp : 1;
  58
  59     const char *helo_name;
  60     const char *queue_id;
  61     const char *sender;
  62     const char *recipient;
  63     const char *recipient_count;
  64     const char *client_address;
  65     const char *client_name;
  66     const char *rclient_name;
  67     const char *instance;
  68
  69     /* postfix 2.2+ */
  70     const char *sasl_method;
  71     const char *sasl_username;
  72     const char *sasl_sender;
  73     const char *size;
  74     const char *ccert_subject;
  75     const char *ccert_issuer;
  76     const char *ccsert_fingerprint;
  77
  78     /* postfix 2.3+ */
  79     const char *encryption_protocol;
  80     const char *encryption_cipher;
  81     const char *encryption_keysize;
  82     const char *etrn_domain;
  83
  84     buffer_t data;
  85 } query_t;
  86
  87 static query_t *query_init(query_t *rq) {
  88     memset(rq, 0, offsetof(query_t, data));
  89     buffer_init(&rq->data);
  90     return rq;
  91 }
  92 static void query_wipe(query_t *rq) {
  93     buffer_wipe(&rq->data);
  94 }
  95
  96 static int xwrite(int fd, const char *s, size_t l)
  97 {
  98     while (l > 0) {
  99         int nb = write(fd, s, l);
 100         if (nb < 0) {
 101             if (errno == EINTR || errno == EAGAIN)
 102                 continue;
 103             return -1;
 104         }
 105         l -= nb;
 106     }
 107     return 0;
 108 }
 109
 110 static int postfix_parsejob(query_t *query)
 111 {
 112 #define PARSE_CHECK(expr, error, ...)                                        \
 113     do {                                                                     \
 114         if (!(expr)) {                                                       \
 115             syslog(LOG_ERR, error, ##__VA_ARGS__);                           \
 116             return -1;                                                       \
 117         }                                                                    \
 118     } while (0)
 119
 120     char *p = vskipspaces(query->data.data);
 121
 122     memset(query, 0, offsetof(query_t, data));
 123     while (p[0] != '\r' || p[1] != '\n') {
 124         char *k, *v;
 125         int klen, vlen, vtk;
 126
 127         while (isblank(*p))
 128             p++;
 129         p = strchr(k = p, '=');
 130         PARSE_CHECK(p, "could not find '=' in line");
 131         for (klen = p - k; klen && isblank(k[klen]); klen--);
 132         p += 1; /* skip = */
 133
 134         while (isblank(*p))
 135             p++;
 136         p = strstr(v = p, "\r\n");
 137         PARSE_CHECK(p, "could not find final \\r\\n in line");
 138         for (vlen = p - v; vlen && isblank(v[vlen]); vlen--);
 139         p += 2; /* skip \r\n */
 140
 141         vtk = tokenize(v, vlen);
 142         switch (tokenize(k, klen)) {
 143 #define CASE(up, low)  case PTK_##up: query->low = v; v[vlen] = '\0'; break;
 144             CASE(HELO_NAME,           helo_name);
 145             CASE(QUEUE_ID,            queue_id);
 146             CASE(SENDER,              sender);
 147             CASE(RECIPIENT,           recipient);
 148             CASE(RECIPIENT_COUNT,     recipient_count);
 149             CASE(CLIENT_ADDRESS,      client_address);
 150             CASE(CLIENT_NAME,         client_name);
 151             CASE(RCLIENT_NAME,        rclient_name);
 152             CASE(INSTANCE,            instance);
 153             CASE(SASL_METHOD,         sasl_method);
 154             CASE(SASL_USERNAME,       sasl_username);
 155             CASE(SASL_SENDER,         sasl_sender);
 156             CASE(SIZE,                size);
 157             CASE(CCERT_SUBJECT,       ccert_subject);
 158             CASE(CCERT_ISSUER,        ccert_issuer);
 159             CASE(CCSERT_FINGERPRINT,  ccsert_fingerprint);
 160             CASE(ENCRYPTION_PROTOCOL, encryption_protocol);
 161             CASE(ENCRYPTION_CIPHER,   encryption_cipher);
 162             CASE(ENCRYPTION_KEYSIZE,  encryption_keysize);
 163             CASE(ETRN_DOMAIN,         etrn_domain);
 164 #undef CASE
 165
 166           case PTK_REQUEST:
 167             PARSE_CHECK(vtk == PTK_SMTPD_ACCESS_POLICY,
 168                         "unexpected `request' value: %.*s", vlen, v);
 169             break;
 170
 171           case PTK_PROTOCOL_NAME:
 172             PARSE_CHECK(vtk == PTK_SMTP || vtk == PTK_ESMTP,
 173                         "unexpected `protocol_name' value: %.*s", vlen, v);
 174             query->esmtp = vtk == PTK_ESMTP;
 175             break;
 176
 177           case PTK_PROTOCOL_STATE:
 178             switch (vtk) {
 179 #define CASE(name)  case PTK_##name: query->state = SMTP_##name; break;
 180                 CASE(CONNECT);
 181                 CASE(EHLO);
 182                 CASE(HELO);
 183                 CASE(MAIL);
 184                 CASE(RCPT);
 185                 CASE(DATA);
 186                 CASE(END_OF_MESSAGE);
 187                 CASE(VRFY);
 188                 CASE(ETRN);
 189               default:
 190                 PARSE_CHECK(false, "unexpected `protocol_state` value: %.*s",
 191                             vlen, v);
 192 #undef CASE
 193             }
 194             break;
 195
 196           default:
 197             syslog(LOG_WARNING, "unexpected key, skipped: %.*s", klen, k);
 198             break;
 199         }
 200     }
 201
 202     return query->state == SMTP_UNKNOWN ? -1 : 0;
 203 #undef PARSE_CHECK
 204 }
 205
 206 void *policy_run(int fd, void *data)
 207 {
 208     query_t q;
 209     query_init(&q);
 210
 211     for (;;) {
 212         int nb = buffer_read(&q.data, fd, -1);
 213         const char *eoq;
 214
 215         if (nb < 0) {
 216             if (errno == EAGAIN || errno == EINTR)
 217                 continue;
 218             UNIXERR("read");
 219             break;
 220         }
 221         if (nb == 0) {
 222             if (q.data.len)
 223                 syslog(LOG_ERR, "unexpected end of data");
 224             break;
 225         }
 226
 227         eoq = strstr(q.data.data + MAX(0, q.data.len - 3), "\r\n\r\n");
 228         if (!eoq)
 229             continue;
 230
 231         if (postfix_parsejob(&q) < 0)
 232             break;
 233
 234         buffer_consume(&q.data, eoq + strlen("\r\n\r\n") - q.data.data);
 235         if (xwrite(fd, "DUNNO\r\n", strlen("DUNNO\r\n"))) {
 236             UNIXERR("write");
 237             break;
 238         }
 239     }
 240
 241     query_wipe(&q);
 242     close(fd);
 243     return NULL;
 244 }