external/ibm-public/postfix/dist/src/smtpd/smtpd.h

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      smtpd 3h
   6 /* SUMMARY
   7 /*      smtp server
   8 /* SYNOPSIS
   9 /*      include "smtpd.h"
  10 /* DESCRIPTION
  11 /* .nf
  12
  13  /*
  14   * System library.
  15   */
  16 #include <sys/time.h>
  17 #include <unistd.h>
  18
  19  /*
  20   * Utility library.
  21   */
  22 #include <vstream.h>
  23 #include <vstring.h>
  24 #include <argv.h>
  25 #include <myaddrinfo.h>
  26
  27  /*
  28   * Global library.
  29   */
  30 #include <mail_stream.h>
  31
  32  /*
  33   * Postfix TLS library.
  34   */
  35 #include <tls.h>
  36
  37  /*
  38   * Milter library.
  39   */
  40 #include <milter.h>
  41
  42  /*
  43   * Variables that keep track of conversation state. There is only one SMTP
  44   * conversation at a time, so the state variables can be made global. And
  45   * some of this has to be global anyway, so that the run-time error handler
  46   * can clean up in case of a fatal error deep down in some library routine.
  47   */
  48 typedef struct SMTPD_DEFER {
  49     int     active;                     /* is this active */
  50     VSTRING *reason;                    /* reason for deferral */
  51     VSTRING *dsn;                       /* DSN detail */
  52     int     code;                       /* SMTP reply code */
  53     int     class;                      /* error notification class */
  54 } SMTPD_DEFER;
  55
  56 typedef struct {
  57     int     flags;                      /* XFORWARD server state */
  58     char   *name;                       /* name for access control */
  59     char   *addr;                       /* address for access control */
  60     char   *port;                       /* port for logging */
  61     char   *namaddr;                    /* name[address]:port */
  62     char   *rfc_addr;                   /* address for RFC 2821 */
  63     char   *protocol;                   /* email protocol */
  64     char   *helo_name;                  /* helo/ehlo parameter */
  65     char   *ident;                      /* message identifier */
  66     char   *domain;                     /* rewrite context */
  67 } SMTPD_XFORWARD_ATTR;
  68
  69 typedef struct SMTPD_STATE {
  70     int     flags;                      /* see below */
  71     int     err;                        /* cleanup server/queue file errors */
  72     VSTREAM *client;                    /* SMTP client handle */
  73     VSTRING *buffer;                    /* SMTP client buffer */
  74     VSTRING *addr_buf;                  /* internalized address buffer */
  75     char   *service;                    /* for event rate control */
  76     struct timeval arrival_time;        /* start of MAIL FROM transaction */
  77     char   *name;                       /* verified client hostname */
  78     char   *reverse_name;               /* unverified client hostname */
  79     char   *addr;                       /* client host address string */
  80     char   *port;                       /* port for logging */
  81     char   *namaddr;                    /* name[address]:port */
  82     char   *rfc_addr;                   /* address for RFC 2821 */
  83     int     addr_family;                /* address family */
  84     struct sockaddr_storage sockaddr;   /* binary client endpoint */
  85     int     name_status;                /* 2=ok 4=soft 5=hard 6=forged */
  86     int     reverse_name_status;        /* 2=ok 4=soft 5=hard */
  87     int     conn_count;                 /* connections from this client */
  88     int     conn_rate;                  /* connection rate for this client */
  89     int     error_count;                /* reset after DOT */
  90     int     error_mask;                 /* client errors */
  91     int     notify_mask;                /* what to report to postmaster */
  92     char   *helo_name;                  /* client HELO/EHLO argument */
  93     char   *queue_id;                   /* from cleanup server/queue file */
  94     VSTREAM *cleanup;                   /* cleanup server/queue file handle */
  95     MAIL_STREAM *dest;                  /* another server/file handle */
  96     int     rcpt_count;                 /* number of accepted recipients */
  97     char   *access_denied;              /* fixme */
  98     ARGV   *history;                    /* protocol transcript */
  99     char   *reason;                     /* cause of connection loss */
 100     char   *sender;                     /* sender address */
 101     char   *encoding;                   /* owned by mail_cmd() */
 102     char   *verp_delims;                /* owned by mail_cmd() */
 103     char   *recipient;                  /* recipient address */
 104     char   *etrn_name;                  /* client ETRN argument */
 105     char   *protocol;                   /* SMTP or ESMTP */
 106     char   *where;                      /* protocol stage */
 107     int     recursion;                  /* Kellerspeicherpegelanzeiger */
 108     off_t   msg_size;                   /* MAIL FROM message size */
 109     off_t   act_size;                   /* END-OF-DATA message size */
 110     int     junk_cmds;                  /* counter */
 111     int     rcpt_overshoot;             /* counter */
 112     char   *rewrite_context;            /* address rewriting context */
 113
 114     /*
 115      * SASL specific.
 116      */
 117 #ifdef USE_SASL_AUTH
 118     struct XSASL_SERVER *sasl_server;
 119     VSTRING *sasl_reply;
 120     char   *sasl_mechanism_list;
 121     char   *sasl_method;
 122     char   *sasl_username;
 123     char   *sasl_sender;
 124 #endif
 125
 126     /*
 127      * Specific to smtpd access checks.
 128      */
 129     int     sender_rcptmap_checked;     /* sender validated against maps */
 130     int     recipient_rcptmap_checked;  /* recipient validated against maps */
 131     int     warn_if_reject;             /* force reject into warning */
 132     SMTPD_DEFER defer_if_reject;        /* force reject into deferral */
 133     SMTPD_DEFER defer_if_permit;        /* force permit into deferral */
 134     int     defer_if_permit_client;     /* force permit into warning */
 135     int     defer_if_permit_helo;       /* force permit into warning */
 136     int     defer_if_permit_sender;     /* force permit into warning */
 137     int     discard;                    /* discard message */
 138     char   *saved_filter;               /* postponed filter action */
 139     char   *saved_redirect;             /* postponed redirect action */
 140     char   *saved_bcc;                  /* postponed bcc action */
 141     int     saved_flags;                /* postponed hold/discard */
 142 #ifdef DELAY_ACTION
 143     int     saved_delay;                /* postponed deferred delay */
 144 #endif
 145     VSTRING *expand_buf;                /* scratch space for $name expansion */
 146     ARGV   *prepend;                    /* prepended headers */
 147     VSTRING *instance;                  /* policy query correlation */
 148     int     seqno;                      /* policy query correlation */
 149     int     ehlo_discard_mask;          /* suppressed EHLO features */
 150     char   *dsn_envid;                  /* temporary MAIL FROM state */
 151     int     dsn_ret;                    /* temporary MAIL FROM state */
 152     VSTRING *dsn_buf;                   /* scratch space for xtext expansion */
 153     VSTRING *dsn_orcpt_buf;             /* scratch space for ORCPT parsing */
 154
 155     /*
 156      * Pass-through proxy client.
 157      */
 158     VSTREAM *proxy;                     /* proxy handle */
 159     VSTRING *proxy_buffer;              /* proxy query/reply buffer */
 160     char   *proxy_mail;                 /* owned by mail_cmd() */
 161     int     proxy_xforward_features;    /* XFORWARD proxy state */
 162
 163     /*
 164      * XFORWARD server state.
 165      */
 166     SMTPD_XFORWARD_ATTR xforward;       /* up-stream logging info */
 167
 168     /*
 169      * TLS related state.
 170      */
 171 #ifdef USE_TLS
 172     int     tls_use_tls;                /* can use TLS */
 173     int     tls_enforce_tls;            /* must use TLS */
 174     int     tls_auth_only;              /* use SASL over TLS only */
 175     TLS_SESS_STATE *tls_context;        /* TLS session state */
 176 #endif
 177
 178     /*
 179      * Milter support.
 180      */
 181     const char **milter_argv;           /* SMTP command vector */
 182     ssize_t milter_argc;                /* SMTP command vector */
 183     const char *milter_reject_text;     /* input to call-back from Milter */
 184 } SMTPD_STATE;
 185
 186 #define SMTPD_FLAG_HANGUP          (1<<0)       /* 421/521 disconnect */
 187 #define SMTPD_FLAG_ILL_PIPELINING  (1<<1)       /* inappropriate pipelining */
 188
 189 #define SMTPD_MASK_MAIL_KEEP            ~0      /* keep all after MAIL reset */
 190
 191 #define SMTPD_STATE_XFORWARD_INIT  (1<<0)       /* xforward preset done */
 192 #define SMTPD_STATE_XFORWARD_NAME  (1<<1)       /* client name received */
 193 #define SMTPD_STATE_XFORWARD_ADDR  (1<<2)       /* client address received */
 194 #define SMTPD_STATE_XFORWARD_PROTO (1<<3)       /* protocol received */
 195 #define SMTPD_STATE_XFORWARD_HELO  (1<<4)       /* client helo received */
 196 #define SMTPD_STATE_XFORWARD_IDENT (1<<5)       /* message identifier */
 197 #define SMTPD_STATE_XFORWARD_DOMAIN (1<<6)      /* message identifier */
 198 #define SMTPD_STATE_XFORWARD_PORT  (1<<7)       /* client port received */
 199
 200 #define SMTPD_STATE_XFORWARD_CLIENT_MASK \
 201         (SMTPD_STATE_XFORWARD_NAME | SMTPD_STATE_XFORWARD_ADDR \
 202         | SMTPD_STATE_XFORWARD_PROTO | SMTPD_STATE_XFORWARD_HELO \
 203         | SMTPD_STATE_XFORWARD_PORT)
 204
 205 extern void smtpd_state_init(SMTPD_STATE *, VSTREAM *, const char *);
 206 extern void smtpd_state_reset(SMTPD_STATE *);
 207
 208  /*
 209   * Conversation stages.  This is used for "lost connection after XXX"
 210   * diagnostics.
 211   */
 212 #define SMTPD_AFTER_CONNECT     "CONNECT"
 213 #define SMTPD_AFTER_DATA        "DATA content"
 214 #define SMTPD_AFTER_DOT         "END-OF-MESSAGE"
 215
 216  /*
 217   * Other stages. These are sometimes used to change the way information is
 218   * logged or what information will be available for access control.
 219   */
 220 #define SMTPD_CMD_HELO          "HELO"
 221 #define SMTPD_CMD_EHLO          "EHLO"
 222 #define SMTPD_CMD_STARTTLS      "STARTTLS"
 223 #define SMTPD_CMD_AUTH          "AUTH"
 224 #define SMTPD_CMD_MAIL          "MAIL"
 225 #define SMTPD_CMD_RCPT          "RCPT"
 226 #define SMTPD_CMD_DATA          "DATA"
 227 #define SMTPD_CMD_EOD           SMTPD_AFTER_DOT /* XXX Was: END-OF-DATA */
 228 #define SMTPD_CMD_RSET          "RSET"
 229 #define SMTPD_CMD_NOOP          "NOOP"
 230 #define SMTPD_CMD_VRFY          "VRFY"
 231 #define SMTPD_CMD_ETRN          "ETRN"
 232 #define SMTPD_CMD_QUIT          "QUIT"
 233 #define SMTPD_CMD_XCLIENT       "XCLIENT"
 234 #define SMTPD_CMD_XFORWARD      "XFORWARD"
 235 #define SMTPD_CMD_UNKNOWN       "UNKNOWN"
 236
 237  /*
 238   * Representation of unknown and non-existent client information. Throughout
 239   * Postfix, we use the "unknown" string value for unknown client information
 240   * (e.g., unknown remote client hostname), and we use the empty string, null
 241   * pointer or "no queue file record" for non-existent client information
 242   * (e.g., no HELO command, or local submission).
 243   *
 244   * Inside the SMTP server, unknown real client attributes are represented by
 245   * the string "unknown", and non-existent HELO is represented as a null
 246   * pointer. The SMTP server uses this same representation internally for
 247   * forwarded client attributes; the XFORWARD syntax makes no distinction
 248   * between unknown (remote submission) and non-existent (local submission).
 249   *
 250   * The SMTP client sends forwarded client attributes only when upstream client
 251   * attributes exist (i.e. remote submission). Thus, local submissions will
 252   * appear to come from an SMTP-based content filter, which is acceptable.
 253   *
 254   * Known/unknown client attribute values use the SMTP server's internal
 255   * representation in queue files, in queue manager delivery requests, and in
 256   * delivery agent $name expansions.
 257   *
 258   * Non-existent attribute values are never present in queue files. Non-existent
 259   * information is represented as empty strings in queue manager delivery
 260   * requests and in delivery agent $name expansions.
 261   */
 262 #define CLIENT_ATTR_UNKNOWN     "unknown"
 263
 264 #define CLIENT_NAME_UNKNOWN     CLIENT_ATTR_UNKNOWN
 265 #define CLIENT_ADDR_UNKNOWN     CLIENT_ATTR_UNKNOWN
 266 #define CLIENT_PORT_UNKNOWN     CLIENT_ATTR_UNKNOWN
 267 #define CLIENT_NAMADDR_UNKNOWN  CLIENT_ATTR_UNKNOWN
 268 #define CLIENT_HELO_UNKNOWN     0
 269 #define CLIENT_PROTO_UNKNOWN    CLIENT_ATTR_UNKNOWN
 270 #define CLIENT_IDENT_UNKNOWN    0
 271 #define CLIENT_DOMAIN_UNKNOWN   0
 272
 273 #define IS_AVAIL_CLIENT_ATTR(v) ((v) && strcmp((v), CLIENT_ATTR_UNKNOWN))
 274
 275 #define IS_AVAIL_CLIENT_NAME(v) IS_AVAIL_CLIENT_ATTR(v)
 276 #define IS_AVAIL_CLIENT_ADDR(v) IS_AVAIL_CLIENT_ATTR(v)
 277 #define IS_AVAIL_CLIENT_PORT(v) IS_AVAIL_CLIENT_ATTR(v)
 278 #define IS_AVAIL_CLIENT_NAMADDR(v) IS_AVAIL_CLIENT_ATTR(v)
 279 #define IS_AVAIL_CLIENT_HELO(v) ((v) != 0)
 280 #define IS_AVAIL_CLIENT_PROTO(v) IS_AVAIL_CLIENT_ATTR(v)
 281 #define IS_AVAIL_CLIENT_IDENT(v) ((v) != 0)
 282 #define IS_AVAIL_CLIENT_DOMAIN(v) ((v) != 0)
 283
 284  /*
 285   * If running in stand-alone mode, do not try to talk to Postfix daemons but
 286   * write to queue file instead.
 287   */
 288 #define SMTPD_STAND_ALONE(state) \
 289         (state->client == VSTREAM_IN && getuid() != var_owner_uid)
 290
 291  /*
 292   * If running as proxy front-end, disable actions that require communication
 293   * with the cleanup server.
 294   */
 295 #define USE_SMTPD_PROXY(state) \
 296         (SMTPD_STAND_ALONE(state) == 0 && *var_smtpd_proxy_filt)
 297
 298  /*
 299   * SMTPD peer information lookup.
 300   */
 301 extern void smtpd_peer_init(SMTPD_STATE *state);
 302 extern void smtpd_peer_reset(SMTPD_STATE *state);
 303
 304 #define SMTPD_PEER_CODE_OK      2
 305 #define SMTPD_PEER_CODE_TEMP    4
 306 #define SMTPD_PEER_CODE_PERM    5
 307 #define SMTPD_PEER_CODE_FORGED  6
 308
 309  /*
 310   * Construct name[addr] or name[addr]:port as appropriate
 311   */
 312 #define SMTPD_BUILD_NAMADDRPORT(name, addr, port) \
 313         concatenate((name), "[", (addr), "]", \
 314                     var_smtpd_client_port_log ? ":" : (char *) 0, \
 315                     (port), (char *) 0)
 316
 317  /*
 318   * Don't mix information from the current SMTP session with forwarded
 319   * information from an up-stream session.
 320   */
 321 #define FORWARD_CLIENT_ATTR(s, a) \
 322         (((s)->xforward.flags & SMTPD_STATE_XFORWARD_CLIENT_MASK) ? \
 323             (s)->xforward.a : (s)->a)
 324
 325 #define FORWARD_ADDR(s)         FORWARD_CLIENT_ATTR((s), rfc_addr)
 326 #define FORWARD_NAME(s)         FORWARD_CLIENT_ATTR((s), name)
 327 #define FORWARD_NAMADDR(s)      FORWARD_CLIENT_ATTR((s), namaddr)
 328 #define FORWARD_PROTO(s)        FORWARD_CLIENT_ATTR((s), protocol)
 329 #define FORWARD_HELO(s)         FORWARD_CLIENT_ATTR((s), helo_name)
 330 #define FORWARD_PORT(s)         FORWARD_CLIENT_ATTR((s), port)
 331
 332 #define FORWARD_IDENT(s) \
 333         (((s)->xforward.flags & SMTPD_STATE_XFORWARD_IDENT) ? \
 334             (s)->queue_id : (s)->ident)
 335
 336 #define FORWARD_DOMAIN(s) \
 337         (((s)->xforward.flags & SMTPD_STATE_XFORWARD_DOMAIN) ? \
 338             (s)->xforward.domain : (s)->rewrite_context)
 339
 340 extern void smtpd_xforward_init(SMTPD_STATE *);
 341 extern void smtpd_xforward_preset(SMTPD_STATE *);
 342 extern void smtpd_xforward_reset(SMTPD_STATE *);
 343
 344  /*
 345   * Transparency: before mail is queued, do we check for unknown recipients,
 346   * do we allow address mapping, automatic bcc, header/body checks?
 347   */
 348 extern int smtpd_input_transp_mask;
 349
 350  /*
 351   * More Milter support.
 352   */
 353 extern MILTERS *smtpd_milters;
 354
 355 /* LICENSE
 356 /* .ad
 357 /* .fi
 358 /*      The Secure Mailer license must be distributed with this software.
 359 /* AUTHOR(S)
 360 /*      Wietse Venema
 361 /*      IBM T.J. Watson Research
 362 /*      P.O. Box 704
 363 /*      Yorktown Heights, NY 10598, USA
 364 /*
 365 /*      TLS support originally by:
 366 /*      Lutz Jaenicke
 367 /*      BTU Cottbus
 368 /*      Allgemeine Elektrotechnik
 369 /*      Universitaetsplatz 3-4
 370 /*      D-03044 Cottbus, Germany
 371 /*--*/