/*++ /* NAME /* smtp 3h /* SUMMARY /* smtp client program /* SYNOPSIS /* #include "smtp.h" /* DESCRIPTION /* .nf /* * System library. */ #include <string.h> /* * Utility library. */ #include <vstream.h> #include <vstring.h> #include <argv.h> #include <htable.h> /* * Global library. */ #include <deliver_request.h> #include <scache.h> #include <string_list.h> #include <maps.h> #include <tok822.h> #include <dsn_buf.h> #include <header_body_checks.h> /* * Postfix TLS library. */ #include <tls.h> /* * State information associated with each SMTP delivery request. * Session-specific state is stored separately. */ typedef struct SMTP_STATE { int misc_flags; /* processing flags, see below */ VSTREAM *src; /* queue file stream */ const char *service; /* transport name */ DELIVER_REQUEST *request; /* envelope info, offsets */ struct SMTP_SESSION *session; /* network connection */ int status; /* delivery status */ ssize_t space_left; /* output length control */ /* * Connection cache support. The (nexthop_lookup_mx, nexthop_domain, * nexthop_port) triple is a parsed next-hop specification, and should be * a data type by itself. The (service, nexthop_mumble) members specify * the name under which the first good connection should be cached. The * nexthop_mumble members are initialized by the connection management * module. nexthop_domain is reset to null after one connection is saved * under the (service, nexthop_mumble) label, or upon exit from the * connection management module. */ HTABLE *cache_used; /* cached addresses that were used */ VSTRING *dest_label; /* cached logical/physical binding */ VSTRING *dest_prop; /* binding properties, passivated */ VSTRING *endp_label; /* cached session physical endpoint */ VSTRING *endp_prop; /* endpoint properties, passivated */ int nexthop_lookup_mx; /* do/don't MX expand nexthop_domain */ char *nexthop_domain; /* next-hop name or bare address */ unsigned nexthop_port; /* next-hop TCP port, network order */ /* * Flags and counters to control the handling of mail delivery errors. * There is some redundancy for sanity checking. At the end of an SMTP * session all recipients should be marked one way or the other. */ int rcpt_left; /* recipients left over */ int rcpt_drop; /* recipients marked as drop */ int rcpt_keep; /* recipients marked as keep */ /* * DSN Support introduced major bloat in error processing. */ DSN_BUF *why; /* on-the-fly formatting buffer */ } SMTP_STATE; #define SET_NEXTHOP_STATE(state, lookup_mx, domain, port) { \ (state)->nexthop_lookup_mx = lookup_mx; \ (state)->nexthop_domain = mystrdup(domain); \ (state)->nexthop_port = port; \ } #define FREE_NEXTHOP_STATE(state) { \ myfree((state)->nexthop_domain); \ (state)->nexthop_domain = 0; \ } #define HAVE_NEXTHOP_STATE(state) ((state)->nexthop_domain != 0) /* * Server features. */ #define SMTP_FEATURE_ESMTP (1<<0) #define SMTP_FEATURE_8BITMIME (1<<1) #define SMTP_FEATURE_PIPELINING (1<<2) #define SMTP_FEATURE_SIZE (1<<3) #define SMTP_FEATURE_STARTTLS (1<<4) #define SMTP_FEATURE_AUTH (1<<5) #define SMTP_FEATURE_XFORWARD_NAME (1<<7) #define SMTP_FEATURE_XFORWARD_ADDR (1<<8) #define SMTP_FEATURE_XFORWARD_PROTO (1<<9) #define SMTP_FEATURE_XFORWARD_HELO (1<<10) #define SMTP_FEATURE_XFORWARD_DOMAIN (1<<11) #define SMTP_FEATURE_BEST_MX (1<<12) /* for next-hop or fall-back */ #define SMTP_FEATURE_RSET_REJECTED (1<<13) /* RSET probe rejected */ #define SMTP_FEATURE_FROM_CACHE (1<<14) /* cached connection */ #define SMTP_FEATURE_DSN (1<<15) /* DSN supported */ #define SMTP_FEATURE_PIX_NO_ESMTP (1<<16) /* PIX smtp fixup mode */ #define SMTP_FEATURE_PIX_DELAY_DOTCRLF (1<<17) /* PIX smtp fixup mode */ #define SMTP_FEATURE_XFORWARD_PORT (1<<18) /* * Features that passivate under the endpoint. */ #define SMTP_FEATURE_ENDPOINT_MASK \ (~(SMTP_FEATURE_BEST_MX | SMTP_FEATURE_RSET_REJECTED \ | SMTP_FEATURE_FROM_CACHE)) /* * Features that passivate under the logical destination. */ #define SMTP_FEATURE_DESTINATION_MASK (SMTP_FEATURE_BEST_MX) /* * Misc flags. */ #define SMTP_MISC_FLAG_LOOP_DETECT (1<<0) #define SMTP_MISC_FLAG_IN_STARTTLS (1<<1) #define SMTP_MISC_FLAG_USE_LMTP (1<<2) #define SMTP_MISC_FLAG_FIRST_NEXTHOP (1<<3) #define SMTP_MISC_FLAG_FINAL_NEXTHOP (1<<4) #define SMTP_MISC_FLAG_FINAL_SERVER (1<<5) #define SMTP_MISC_FLAG_CONN_LOAD (1<<6) #define SMTP_MISC_FLAG_CONN_STORE (1<<7) #define SMTP_MISC_FLAG_COMPLETE_SESSION (1<<8) #define SMTP_MISC_FLAG_CONN_CACHE_MASK \ (SMTP_MISC_FLAG_CONN_LOAD | SMTP_MISC_FLAG_CONN_STORE) /* * smtp.c */ #define SMTP_HAS_DSN(why) (STR((why)->status)[0] != 0) #define SMTP_HAS_SOFT_DSN(why) (STR((why)->status)[0] == '4') #define SMTP_HAS_HARD_DSN(why) (STR((why)->status)[0] == '5') #define SMTP_HAS_LOOP_DSN(why) \ (SMTP_HAS_DSN(why) && strcmp(STR((why)->status) + 1, ".4.6") == 0) #define SMTP_SET_SOFT_DSN(why) (STR((why)->status)[0] = '4') #define SMTP_SET_HARD_DSN(why) (STR((why)->status)[0] = '5') extern int smtp_host_lookup_mask; /* host lookup methods to use */ #define SMTP_HOST_FLAG_DNS (1<<0) #define SMTP_HOST_FLAG_NATIVE (1<<1) extern SCACHE *smtp_scache; /* connection cache instance */ extern STRING_LIST *smtp_cache_dest; /* cached destinations */ extern MAPS *smtp_ehlo_dis_maps; /* ehlo keyword filter */ extern MAPS *smtp_pix_bug_maps; /* PIX workarounds */ extern MAPS *smtp_generic_maps; /* make internal address valid */ extern int smtp_ext_prop_mask; /* address externsion propagation */ #ifdef USE_TLS extern TLS_APPL_STATE *smtp_tls_ctx; /* client-side TLS engine */ #endif extern HBC_CHECKS *smtp_header_checks; /* limited header checks */ extern HBC_CHECKS *smtp_body_checks; /* limited body checks */ /* * smtp_session.c */ typedef struct SMTP_SESSION { VSTREAM *stream; /* network connection */ char *dest; /* nexthop or fallback */ char *host; /* mail exchanger */ char *addr; /* mail exchanger */ char *namaddr; /* mail exchanger */ char *helo; /* helo response */ unsigned port; /* network byte order */ char *namaddrport; /* mail exchanger, incl. port */ VSTRING *buffer; /* I/O buffer */ VSTRING *scratch; /* scratch buffer */ VSTRING *scratch2; /* scratch buffer */ int features; /* server features */ off_t size_limit; /* server limit or unknown */ ARGV *history; /* transaction log */ int error_mask; /* error classes */ struct MIME_STATE *mime_state; /* mime state machine */ int sndbufsize; /* PIPELINING buffer size */ int send_proto_helo; /* XFORWARD support */ time_t expire_time; /* session reuse expiration time */ int reuse_count; /* # of times reused (for logging) */ int dead; /* No further I/O allowed */ #ifdef USE_SASL_AUTH char *sasl_mechanism_list; /* server mechanism list */ char *sasl_username; /* client username */ char *sasl_passwd; /* client password */ struct XSASL_CLIENT *sasl_client; /* SASL internal state */ VSTRING *sasl_reply; /* client response */ #endif /* * TLS related state, don't forget to initialize in session_tls_init()! */ #ifdef USE_TLS TLS_SESS_STATE *tls_context; /* TLS session state */ char *tls_nexthop; /* Nexthop domain for cert checks */ int tls_level; /* TLS enforcement level */ int tls_retry_plain; /* Try plain when TLS handshake fails */ char *tls_protocols; /* Acceptable SSL protocols */ char *tls_grade; /* Cipher grade: "export", ... */ VSTRING *tls_exclusions; /* Excluded SSL ciphers */ ARGV *tls_matchargv; /* Cert match patterns */ #endif SMTP_STATE *state; /* back link */ } SMTP_SESSION; extern SMTP_SESSION *smtp_session_alloc(VSTREAM *, const char *, const char *, const char *, unsigned, time_t, int); extern void smtp_session_free(SMTP_SESSION *); extern int smtp_session_passivate(SMTP_SESSION *, VSTRING *, VSTRING *); extern SMTP_SESSION *smtp_session_activate(int, VSTRING *, VSTRING *); #ifdef USE_TLS extern void smtp_tls_list_init(void); #endif /* * What's in a name? */ #define SMTP_HNAME(rr) (var_smtp_cname_overr ? (rr)->rname : (rr)->qname) /* * smtp_connect.c */ extern int smtp_connect(SMTP_STATE *); /* * smtp_proto.c */ extern int smtp_helo(SMTP_STATE *); extern int smtp_xfer(SMTP_STATE *); extern int smtp_rset(SMTP_STATE *); extern int smtp_quit(SMTP_STATE *); extern HBC_CALL_BACKS smtp_hbc_callbacks[]; /* * A connection is re-usable if session->expire_time is > 0 and the * expiration time has not been reached. This is subtle because the timer * can expire between sending a command and receiving the reply for that * command. * * But wait, there is more! When SMTP command pipelining is enabled, there are * two protocol loops that execute at very different times: one loop that * generates commands, and one loop that receives replies to those commands. * These will be called "sender loop" and "receiver loop", respectively. At * well-defined protocol synchronization points, the sender loop pauses to * let the receiver loop catch up. * * When we choose to reuse a connection, both the sender and receiver protocol * loops end with "." (mail delivery) or "RSET" (address probe). When we * choose not to reuse, both the sender and receiver protocol loops end with * "QUIT". The problem is that we must make the same protocol choices in * both the sender and receiver loops, even though those loops may execute * at completely different times. * * We "freeze" the choice in the sender loop, just before we generate "." or * "RSET". The reader loop leaves the connection cachable even if the timer * expires by the time the response arrives. The connection cleanup code * will call smtp_quit() for connections with an expired cache expiration * timer. * * We could have made the programmer's life a lot simpler by not making a * choice at all, and always leaving it up to the connection cleanup code to * call smtp_quit() for connections with an expired cache expiration timer. * * As a general principle, neither the sender loop nor the receiver loop must * modify the connection caching state, if that can affect the receiver * state machine for not-yet processed replies to already-generated * commands. This restriction does not apply when we have to exit the * protocol loops prematurely due to e.g., timeout or connection loss, so * that those pending replies will never be received. * * But wait, there is even more! Only the first good connection for a specific * destination may be cached under both the next-hop destination name and * the server address; connections to alternate servers must be cached under * the server address alone. This means we must distinguish between bad * connections and other reasons why connections cannot be cached. */ #define THIS_SESSION_IS_CACHED \ (!THIS_SESSION_IS_DEAD && session->expire_time > 0) #define THIS_SESSION_IS_EXPIRED \ (THIS_SESSION_IS_CACHED \ && session->expire_time < vstream_ftime(session->stream)) #define THIS_SESSION_IS_BAD \ (!THIS_SESSION_IS_DEAD && session->expire_time < 0) #define THIS_SESSION_IS_DEAD \ (session->dead != 0) /* Bring the bad news. */ #define DONT_CACHE_THIS_SESSION \ (session->expire_time = 0) #define DONT_CACHE_BAD_SESSION \ (session->expire_time = -1) #define DONT_USE_DEAD_SESSION \ (session->dead = 1) /* Initialization. */ #define USE_NEWBORN_SESSION \ (session->dead = 0) #define CACHE_THIS_SESSION_UNTIL(when) \ (session->expire_time = (when)) /* * Encapsulate the following so that we don't expose details of of * connection management and error handling to the SMTP protocol engine. */ #define RETRY_AS_PLAINTEXT do { \ session->tls_retry_plain = 1; \ state->misc_flags &= ~SMTP_MISC_FLAG_FINAL_SERVER; \ } while (0) /* * smtp_chat.c */ typedef struct SMTP_RESP { /* server response */ int code; /* SMTP code */ const char *dsn; /* enhanced status */ char *str; /* full reply */ VSTRING *dsn_buf; /* status buffer */ VSTRING *str_buf; /* reply buffer */ } SMTP_RESP; extern void PRINTFLIKE(2, 3) smtp_chat_cmd(SMTP_SESSION *, char *,...); extern SMTP_RESP *smtp_chat_resp(SMTP_SESSION *); extern void smtp_chat_init(SMTP_SESSION *); extern void smtp_chat_reset(SMTP_SESSION *); extern void smtp_chat_notify(SMTP_SESSION *); #define SMTP_RESP_FAKE(resp, _dsn) \ ((resp)->code = 0, \ (resp)->dsn = (_dsn), \ (resp)->str = DSN_BY_LOCAL_MTA, \ (resp)) #define DSN_BY_LOCAL_MTA ((char *) 0) /* DSN issued by local MTA */ /* * These operations implement a redundant mark-and-sweep algorithm that * explicitly accounts for the fate of every recipient. The interface is * documented in smtp_rcpt.c, which also implements the sweeping. The * smtp_trouble.c module does most of the marking after failure. * * When a delivery fails or succeeds, take one of the following actions: * * - Mark the recipient as KEEP (deliver to alternate MTA) and do not update * the delivery request status. * * - Mark the recipient as DROP (remove from delivery request), log whether * delivery succeeded or failed, delete the recipient from the queue file * and/or update defer or bounce logfiles, and update the delivery request * status. * * At the end of a delivery attempt, all recipients must be marked one way or * the other. Failure to do so will trigger a panic. */ #define SMTP_RCPT_STATE_KEEP 1 /* send to backup host */ #define SMTP_RCPT_STATE_DROP 2 /* remove from request */ #define SMTP_RCPT_INIT(state) do { \ (state)->rcpt_drop = (state)->rcpt_keep = 0; \ (state)->rcpt_left = state->request->rcpt_list.len; \ } while (0) #define SMTP_RCPT_DROP(state, rcpt) do { \ (rcpt)->u.status = SMTP_RCPT_STATE_DROP; (state)->rcpt_drop++; \ } while (0) #define SMTP_RCPT_KEEP(state, rcpt) do { \ (rcpt)->u.status = SMTP_RCPT_STATE_KEEP; (state)->rcpt_keep++; \ } while (0) #define SMTP_RCPT_ISMARKED(rcpt) ((rcpt)->u.status != 0) #define SMTP_RCPT_LEFT(state) (state)->rcpt_left extern void smtp_rcpt_cleanup(SMTP_STATE *); extern void smtp_rcpt_done(SMTP_STATE *, SMTP_RESP *, RECIPIENT *); /* * smtp_trouble.c */ extern int smtp_sess_fail(SMTP_STATE *); extern int PRINTFLIKE(4, 5) smtp_site_fail(SMTP_STATE *, const char *, SMTP_RESP *, const char *,...); extern int PRINTFLIKE(4, 5) smtp_mesg_fail(SMTP_STATE *, const char *, SMTP_RESP *, const char *,...); extern void PRINTFLIKE(5, 6) smtp_rcpt_fail(SMTP_STATE *, RECIPIENT *, const char *, SMTP_RESP *, const char *,...); extern int smtp_stream_except(SMTP_STATE *, int, const char *); /* * smtp_unalias.c */ extern const char *smtp_unalias_name(const char *); extern VSTRING *smtp_unalias_addr(VSTRING *, const char *); /* * smtp_state.c */ extern SMTP_STATE *smtp_state_alloc(void); extern void smtp_state_free(SMTP_STATE *); /* * smtp_map11.c */ extern int smtp_map11_external(VSTRING *, MAPS *, int); extern int smtp_map11_tree(TOK822 *, MAPS *, int); extern int smtp_map11_internal(VSTRING *, MAPS *, int); /* * Silly little macros. */ #define STR(s) vstring_str(s) #define LEN(s) VSTRING_LEN(s) /* LICENSE /* .ad /* .fi /* The Secure Mailer license must be distributed with this software. /* AUTHOR(S) /* Wietse Venema /* IBM T.J. Watson Research /* P.O. Box 704 /* Yorktown Heights, NY 10598, USA /* /* TLS support originally by: /* Lutz Jaenicke /* BTU Cottbus /* Allgemeine Elektrotechnik /* Universitaetsplatz 3-4 /* D-03044 Cottbus, Germany /*--*/