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Diffstat (limited to 'src/smtp_in.c')
| -rw-r--r-- | src/smtp_in.c | 5973 |
1 files changed, 5973 insertions, 0 deletions
diff --git a/src/smtp_in.c b/src/smtp_in.c new file mode 100644 index 0000000..86f87ea --- /dev/null +++ b/src/smtp_in.c @@ -0,0 +1,5973 @@ +/************************************************* +* Exim - an Internet mail transport agent * +*************************************************/ + +/* Copyright (c) University of Cambridge 1995 - 2018 */ +/* See the file NOTICE for conditions of use and distribution. */ + +/* Functions for handling an incoming SMTP call. */ + + +#include "exim.h" +#include <assert.h> + + +/* Initialize for TCP wrappers if so configured. It appears that the macro +HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before +including that header, and restore its value afterwards. */ + +#ifdef USE_TCP_WRAPPERS + + #if HAVE_IPV6 + #define EXIM_HAVE_IPV6 + #endif + #undef HAVE_IPV6 + #include <tcpd.h> + #undef HAVE_IPV6 + #ifdef EXIM_HAVE_IPV6 + #define HAVE_IPV6 TRUE + #endif + +int allow_severity = LOG_INFO; +int deny_severity = LOG_NOTICE; +uschar *tcp_wrappers_name; +#endif + + +/* Size of buffer for reading SMTP commands. We used to use 512, as defined +by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP +commands that accept arguments, and this in particular applies to AUTH, where +the data can be quite long. More recently this value was 2048 in Exim; +however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients +such as Thunderbird will send an AUTH with an initial-response for GSSAPI. +The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and +we need room to handle large base64-encoded AUTHs for GSSAPI. +*/ + +#define SMTP_CMD_BUFFER_SIZE 16384 + +/* Size of buffer for reading SMTP incoming packets */ + +#define IN_BUFFER_SIZE 8192 + +/* Structure for SMTP command list */ + +typedef struct { + const char *name; + int len; + short int cmd; + short int has_arg; + short int is_mail_cmd; +} smtp_cmd_list; + +/* Codes for identifying commands. We order them so that those that come first +are those for which synchronization is always required. Checking this can help +block some spam. */ + +enum { + /* These commands are required to be synchronized, i.e. to be the last in a + block of commands when pipelining. */ + + HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */ + VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */ + ETRN_CMD, /* This by analogy with TURN from the RFC */ + STARTTLS_CMD, /* Required by the STARTTLS RFC */ + TLS_AUTH_CMD, /* auto-command at start of SSL */ + + /* This is a dummy to identify the non-sync commands when pipelining */ + + NON_SYNC_CMD_PIPELINING, + + /* These commands need not be synchronized when pipelining */ + + MAIL_CMD, RCPT_CMD, RSET_CMD, + + /* This is a dummy to identify the non-sync commands when not pipelining */ + + NON_SYNC_CMD_NON_PIPELINING, + + /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and + processed the message is sent using a series of BDAT commands" + implies that BDAT should be synchronized. However, we see Google, at least, + sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for + processing of the RCPT response(s). We shall do the same, and not require + synch for BDAT. Worse, as the chunk may (very likely will) follow the + command-header in the same packet we cannot do the usual "is there any + follow-on data after the command line" even for non-pipeline mode. + So we'll need an explicit check after reading the expected chunk amount + when non-pipe, before sending the ACK. */ + + BDAT_CMD, + + /* I have been unable to find a statement about the use of pipelining + with AUTH, so to be on the safe side it is here, though I kind of feel + it should be up there with the synchronized commands. */ + + AUTH_CMD, + + /* I'm not sure about these, but I don't think they matter. */ + + QUIT_CMD, HELP_CMD, + +#ifdef SUPPORT_PROXY + PROXY_FAIL_IGNORE_CMD, +#endif + + /* These are specials that don't correspond to actual commands */ + + EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD, + TOO_MANY_NONMAIL_CMD }; + + +/* This is a convenience macro for adding the identity of an SMTP command +to the circular buffer that holds a list of the last n received. */ + +#define HAD(n) \ + smtp_connection_had[smtp_ch_index++] = n; \ + if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0 + + +/************************************************* +* Local static variables * +*************************************************/ + +static struct { + BOOL auth_advertised :1; +#ifdef SUPPORT_TLS + BOOL tls_advertised :1; +# ifdef EXPERIMENTAL_REQUIRETLS + BOOL requiretls_advertised :1; +# endif +#endif + BOOL dsn_advertised :1; + BOOL esmtp :1; + BOOL helo_required :1; + BOOL helo_verify :1; + BOOL helo_seen :1; + BOOL helo_accept_junk :1; +#ifdef EXPERIMENTAL_PIPE_CONNECT + BOOL pipe_connect_acceptable :1; +#endif + BOOL rcpt_smtp_response_same :1; + BOOL rcpt_in_progress :1; + BOOL smtp_exit_function_called :1; +#ifdef SUPPORT_I18N + BOOL smtputf8_advertised :1; +#endif +} fl = { + .helo_required = FALSE, + .helo_verify = FALSE, + .smtp_exit_function_called = FALSE, +}; + +static auth_instance *authenticated_by; +static int count_nonmail; +static int nonmail_command_count; +static int synprot_error_count; +static int unknown_command_count; +static int sync_cmd_limit; +static int smtp_write_error = 0; + +static uschar *rcpt_smtp_response; +static uschar *smtp_data_buffer; +static uschar *smtp_cmd_data; + +/* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their +final fields of all except AUTH are forced TRUE at the start of a new message +setup, to allow one of each between messages that is not counted as a nonmail +command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to +allow a new EHLO after starting up TLS. + +AUTH is "falsely" labelled as a mail command initially, so that it doesn't get +counted. However, the flag is changed when AUTH is received, so that multiple +failing AUTHs will eventually hit the limit. After a successful AUTH, another +AUTH is already forbidden. After a TLS session is started, AUTH's flag is again +forced TRUE, to allow for the re-authentication that can happen at that point. + +QUIT is also "falsely" labelled as a mail command so that it doesn't up the +count of non-mail commands and possibly provoke an error. + +tls_auth is a pseudo-command, never expected in input. It is activated +on TLS startup and looks for a tls authenticator. */ + +static smtp_cmd_list cmd_list[] = { + /* name len cmd has_arg is_mail_cmd */ + + { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */ + { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE }, + { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE }, + { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE }, +#ifdef SUPPORT_TLS + { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE }, + { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE }, +#endif + +/* If you change anything above here, also fix the definitions below. */ + + { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE }, + { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE }, + { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE }, + { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE }, + { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE }, + { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE }, + { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE }, + { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE }, + { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE }, + { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE } +}; + +static smtp_cmd_list *cmd_list_end = + cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list); + +#define CMD_LIST_RSET 0 +#define CMD_LIST_HELO 1 +#define CMD_LIST_EHLO 2 +#define CMD_LIST_AUTH 3 +#define CMD_LIST_STARTTLS 4 +#define CMD_LIST_TLS_AUTH 5 + +/* This list of names is used for performing the smtp_no_mail logging action. +It must be kept in step with the SCH_xxx enumerations. */ + +static uschar *smtp_names[] = + { + US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN", + US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET", + US"STARTTLS", US"VRFY" }; + +static uschar *protocols_local[] = { + US"local-smtp", /* HELO */ + US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */ + US"local-esmtp", /* EHLO */ + US"local-esmtps", /* EHLO->STARTTLS->EHLO */ + US"local-esmtpa", /* EHLO->AUTH */ + US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */ + }; +static uschar *protocols[] = { + US"smtp", /* HELO */ + US"smtps", /* The rare case EHLO->STARTTLS->HELO */ + US"esmtp", /* EHLO */ + US"esmtps", /* EHLO->STARTTLS->EHLO */ + US"esmtpa", /* EHLO->AUTH */ + US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */ + }; + +#define pnormal 0 +#define pextend 2 +#define pcrpted 1 /* added to pextend or pnormal */ +#define pauthed 2 /* added to pextend */ + +/* Sanity check and validate optional args to MAIL FROM: envelope */ +enum { + ENV_MAIL_OPT_NULL, + ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH, +#ifndef DISABLE_PRDR + ENV_MAIL_OPT_PRDR, +#endif + ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID, +#ifdef SUPPORT_I18N + ENV_MAIL_OPT_UTF8, +#endif +#ifdef EXPERIMENTAL_REQUIRETLS + ENV_MAIL_OPT_REQTLS, +#endif + }; +typedef struct { + uschar * name; /* option requested during MAIL cmd */ + int value; /* enum type */ + BOOL need_value; /* TRUE requires value (name=value pair format) + FALSE is a singleton */ + } env_mail_type_t; +static env_mail_type_t env_mail_type_list[] = { + { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE }, + { US"BODY", ENV_MAIL_OPT_BODY, TRUE }, + { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE }, +#ifndef DISABLE_PRDR + { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE }, +#endif + { US"RET", ENV_MAIL_OPT_RET, TRUE }, + { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE }, +#ifdef SUPPORT_I18N + { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */ +#endif +#ifdef EXPERIMENTAL_REQUIRETLS + /* https://tools.ietf.org/html/draft-ietf-uta-smtp-require-tls-03 */ + { US"REQUIRETLS",ENV_MAIL_OPT_REQTLS, FALSE }, +#endif + /* keep this the last entry */ + { US"NULL", ENV_MAIL_OPT_NULL, FALSE }, + }; + +/* When reading SMTP from a remote host, we have to use our own versions of the +C input-reading functions, in order to be able to flush the SMTP output only +when about to read more data from the socket. This is the only way to get +optimal performance when the client is using pipelining. Flushing for every +command causes a separate packet and reply packet each time; saving all the +responses up (when pipelining) combines them into one packet and one response. + +For simplicity, these functions are used for *all* SMTP input, not only when +receiving over a socket. However, after setting up a secure socket (SSL), input +is read via the OpenSSL library, and another set of functions is used instead +(see tls.c). + +These functions are set in the receive_getc etc. variables and called with the +same interface as the C functions. However, since there can only ever be +one incoming SMTP call, we just use a single buffer and flags. There is no need +to implement a complicated private FILE-like structure.*/ + +static uschar *smtp_inbuffer; +static uschar *smtp_inptr; +static uschar *smtp_inend; +static int smtp_had_eof; +static int smtp_had_error; + + +/* forward declarations */ +static int smtp_read_command(BOOL check_sync, unsigned buffer_lim); +static int synprot_error(int type, int code, uschar *data, uschar *errmess); +static void smtp_quit_handler(uschar **, uschar **); +static void smtp_rset_handler(void); + +/************************************************* +* Recheck synchronization * +*************************************************/ + +/* Synchronization checks can never be perfect because a packet may be on its +way but not arrived when the check is done. Normally, the checks happen when +commands are read: Exim ensures that there is no more input in the input buffer. +In normal cases, the response to the command will be fast, and there is no +further check. + +However, for some commands an ACL is run, and that can include delays. In those +cases, it is useful to do another check on the input just before sending the +response. This also applies at the start of a connection. This function does +that check by means of the select() function, as long as the facility is not +disabled or inappropriate. A failure of select() is ignored. + +When there is unwanted input, we read it so that it appears in the log of the +error. + +Arguments: none +Returns: TRUE if all is well; FALSE if there is input pending +*/ + +static BOOL +wouldblock_reading(void) +{ +int fd, rc; +fd_set fds; +struct timeval tzero; + +#ifdef SUPPORT_TLS +if (tls_in.active.sock >= 0) + return !tls_could_read(); +#endif + +if (smtp_inptr < smtp_inend) + return FALSE; + +fd = fileno(smtp_in); +FD_ZERO(&fds); +FD_SET(fd, &fds); +tzero.tv_sec = 0; +tzero.tv_usec = 0; +rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero); + +if (rc <= 0) return TRUE; /* Not ready to read */ +rc = smtp_getc(GETC_BUFFER_UNLIMITED); +if (rc < 0) return TRUE; /* End of file or error */ + +smtp_ungetc(rc); +return FALSE; +} + +static BOOL +check_sync(void) +{ +if (!smtp_enforce_sync || !sender_host_address || f.sender_host_notsocket) + return TRUE; + +return wouldblock_reading(); +} + + +/* If there's input waiting (and we're doing pipelineing) then we can pipeline +a reponse with the one following. */ + +static BOOL +pipeline_response(void) +{ +if ( !smtp_enforce_sync || !sender_host_address + || f.sender_host_notsocket || !f.smtp_in_pipelining_advertised) + return FALSE; + +if (wouldblock_reading()) return FALSE; +f.smtp_in_pipelining_used = TRUE; +return TRUE; +} + + +#ifdef EXPERIMENTAL_PIPE_CONNECT +static BOOL +pipeline_connect_sends(void) +{ +if (!sender_host_address || f.sender_host_notsocket || !fl.pipe_connect_acceptable) + return FALSE; + +if (wouldblock_reading()) return FALSE; +f.smtp_in_early_pipe_used = TRUE; +return TRUE; +} +#endif + +/************************************************* +* Log incomplete transactions * +*************************************************/ + +/* This function is called after a transaction has been aborted by RSET, QUIT, +connection drops or other errors. It logs the envelope information received +so far in order to preserve address verification attempts. + +Argument: string to indicate what aborted the transaction +Returns: nothing +*/ + +static void +incomplete_transaction_log(uschar *what) +{ +if (sender_address == NULL || /* No transaction in progress */ + !LOGGING(smtp_incomplete_transaction)) + return; + +/* Build list of recipients for logging */ + +if (recipients_count > 0) + { + int i; + raw_recipients = store_get(recipients_count * sizeof(uschar *)); + for (i = 0; i < recipients_count; i++) + raw_recipients[i] = recipients_list[i].address; + raw_recipients_count = recipients_count; + } + +log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS, + "%s incomplete transaction (%s)", host_and_ident(TRUE), what); +} + + + + +void +smtp_command_timeout_exit(void) +{ +log_write(L_lost_incoming_connection, + LOG_MAIN, "SMTP command timeout on%s connection from %s", + tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE)); +if (smtp_batched_input) + moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */ +smtp_notquit_exit(US"command-timeout", US"421", + US"%s: SMTP command timeout - closing connection", + smtp_active_hostname); +exim_exit(EXIT_FAILURE, US"receiving"); +} + +void +smtp_command_sigterm_exit(void) +{ +log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info()); +if (smtp_batched_input) + moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */ +smtp_notquit_exit(US"signal-exit", US"421", + US"%s: Service not available - closing connection", smtp_active_hostname); +exim_exit(EXIT_FAILURE, US"receiving"); +} + +void +smtp_data_timeout_exit(void) +{ +log_write(L_lost_incoming_connection, + LOG_MAIN, "SMTP data timeout (message abandoned) on connection from %s F=<%s>", + sender_fullhost ? sender_fullhost : US"local process", sender_address); +receive_bomb_out(US"data-timeout", US"SMTP incoming data timeout"); +/* Does not return */ +} + +void +smtp_data_sigint_exit(void) +{ +log_write(0, LOG_MAIN, "%s closed after %s", + smtp_get_connection_info(), had_data_sigint == SIGTERM ? "SIGTERM":"SIGINT"); +receive_bomb_out(US"signal-exit", + US"Service not available - SIGTERM or SIGINT received"); +/* Does not return */ +} + + + +/* Refill the buffer, and notify DKIM verification code. +Return false for error or EOF. +*/ + +static BOOL +smtp_refill(unsigned lim) +{ +int rc, save_errno; +if (!smtp_out) return FALSE; +fflush(smtp_out); +if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout); + +/* Limit amount read, so non-message data is not fed to DKIM. +Take care to not touch the safety NUL at the end of the buffer. */ + +rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE-1, lim)); +save_errno = errno; +if (smtp_receive_timeout > 0) ALARM_CLR(0); +if (rc <= 0) + { + /* Must put the error text in fixed store, because this might be during + header reading, where it releases unused store above the header. */ + if (rc < 0) + { + if (had_command_timeout) /* set by signal handler */ + smtp_command_timeout_exit(); /* does not return */ + if (had_command_sigterm) + smtp_command_sigterm_exit(); + if (had_data_timeout) + smtp_data_timeout_exit(); + if (had_data_sigint) + smtp_data_sigint_exit(); + + smtp_had_error = save_errno; + smtp_read_error = string_copy_malloc( + string_sprintf(" (error: %s)", strerror(save_errno))); + } + else + smtp_had_eof = 1; + return FALSE; + } +#ifndef DISABLE_DKIM +dkim_exim_verify_feed(smtp_inbuffer, rc); +#endif +smtp_inend = smtp_inbuffer + rc; +smtp_inptr = smtp_inbuffer; +return TRUE; +} + +/************************************************* +* SMTP version of getc() * +*************************************************/ + +/* This gets the next byte from the SMTP input buffer. If the buffer is empty, +it flushes the output, and refills the buffer, with a timeout. The signal +handler is set appropriately by the calling function. This function is not used +after a connection has negotiated itself into an TLS/SSL state. + +Arguments: lim Maximum amount to read/buffer +Returns: the next character or EOF +*/ + +int +smtp_getc(unsigned lim) +{ +if (smtp_inptr >= smtp_inend) + if (!smtp_refill(lim)) + return EOF; +return *smtp_inptr++; +} + +uschar * +smtp_getbuf(unsigned * len) +{ +unsigned size; +uschar * buf; + +if (smtp_inptr >= smtp_inend) + if (!smtp_refill(*len)) + { *len = 0; return NULL; } + +if ((size = smtp_inend - smtp_inptr) > *len) size = *len; +buf = smtp_inptr; +smtp_inptr += size; +*len = size; +return buf; +} + +void +smtp_get_cache(void) +{ +#ifndef DISABLE_DKIM +int n = smtp_inend - smtp_inptr; +if (n > 0) + dkim_exim_verify_feed(smtp_inptr, n); +#endif +} + + +/* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the +previous BDAT chunk and getting new ones when we run out. Uses the +underlying smtp_getc or tls_getc both for that and for getting the +(buffered) data byte. EOD signals (an expected) no further data. +ERR signals a protocol error, and EOF a closed input stream. + +Called from read_bdat_smtp() in receive.c for the message body, but also +by the headers read loop in receive_msg(); manipulates chunking_state +to handle the BDAT command/response. +Placed here due to the correlation with the above smtp_getc(), which it wraps, +and also by the need to do smtp command/response handling. + +Arguments: lim (ignored) +Returns: the next character or ERR, EOD or EOF +*/ + +int +bdat_getc(unsigned lim) +{ +uschar * user_msg = NULL; +uschar * log_msg; + +for(;;) + { +#ifndef DISABLE_DKIM + unsigned dkim_save; +#endif + + if (chunking_data_left > 0) + return lwr_receive_getc(chunking_data_left--); + + receive_getc = lwr_receive_getc; + receive_getbuf = lwr_receive_getbuf; + receive_ungetc = lwr_receive_ungetc; +#ifndef DISABLE_DKIM + dkim_save = dkim_collect_input; + dkim_collect_input = 0; +#endif + + /* Unless PIPELINING was offered, there should be no next command + until after we ack that chunk */ + + if (!f.smtp_in_pipelining_advertised && !check_sync()) + { + unsigned n = smtp_inend - smtp_inptr; + if (n > 32) n = 32; + + incomplete_transaction_log(US"sync failure"); + log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error " + "(next input sent too soon: pipelining was not advertised): " + "rejected \"%s\" %s next input=\"%s\"%s", + smtp_cmd_buffer, host_and_ident(TRUE), + string_printing(string_copyn(smtp_inptr, n)), + smtp_inend - smtp_inptr > n ? "..." : ""); + (void) synprot_error(L_smtp_protocol_error, 554, NULL, + US"SMTP synchronization error"); + goto repeat_until_rset; + } + + /* If not the last, ack the received chunk. The last response is delayed + until after the data ACL decides on it */ + + if (chunking_state == CHUNKING_LAST) + { +#ifndef DISABLE_DKIM + dkim_exim_verify_feed(NULL, 0); /* notify EOD */ +#endif + return EOD; + } + + smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize); + chunking_state = CHUNKING_OFFERED; + DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state); + + /* Expect another BDAT cmd from input. RFC 3030 says nothing about + QUIT, RSET or NOOP but handling them seems obvious */ + +next_cmd: + switch(smtp_read_command(TRUE, 1)) + { + default: + (void) synprot_error(L_smtp_protocol_error, 503, NULL, + US"only BDAT permissible after non-LAST BDAT"); + + repeat_until_rset: + switch(smtp_read_command(TRUE, 1)) + { + case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */ + case EOF_CMD: return EOF; + case RSET_CMD: smtp_rset_handler(); return ERR; + default: if (synprot_error(L_smtp_protocol_error, 503, NULL, + US"only RSET accepted now") > 0) + return EOF; + goto repeat_until_rset; + } + + case QUIT_CMD: + smtp_quit_handler(&user_msg, &log_msg); + /*FALLTHROUGH*/ + case EOF_CMD: + return EOF; + + case RSET_CMD: + smtp_rset_handler(); + return ERR; + + case NOOP_CMD: + HAD(SCH_NOOP); + smtp_printf("250 OK\r\n", FALSE); + goto next_cmd; + + case BDAT_CMD: + { + int n; + + if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1) + { + (void) synprot_error(L_smtp_protocol_error, 501, NULL, + US"missing size for BDAT command"); + return ERR; + } + chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0 + ? CHUNKING_LAST : CHUNKING_ACTIVE; + chunking_data_left = chunking_datasize; + DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n", + (int)chunking_state, chunking_data_left); + + if (chunking_datasize == 0) + if (chunking_state == CHUNKING_LAST) + return EOD; + else + { + (void) synprot_error(L_smtp_protocol_error, 504, NULL, + US"zero size for BDAT command"); + goto repeat_until_rset; + } + + receive_getc = bdat_getc; + receive_getbuf = bdat_getbuf; /* r~getbuf is never actually used */ + receive_ungetc = bdat_ungetc; +#ifndef DISABLE_DKIM + dkim_collect_input = dkim_save; +#endif + break; /* to top of main loop */ + } + } + } +} + +uschar * +bdat_getbuf(unsigned * len) +{ +uschar * buf; + +if (chunking_data_left <= 0) + { *len = 0; return NULL; } + +if (*len > chunking_data_left) *len = chunking_data_left; +buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */ +chunking_data_left -= *len; +return buf; +} + +void +bdat_flush_data(void) +{ +while (chunking_data_left) + { + unsigned n = chunking_data_left; + if (!bdat_getbuf(&n)) break; + } + +receive_getc = lwr_receive_getc; +receive_getbuf = lwr_receive_getbuf; +receive_ungetc = lwr_receive_ungetc; + +if (chunking_state != CHUNKING_LAST) + { + chunking_state = CHUNKING_OFFERED; + DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state); + } +} + + + + +/************************************************* +* SMTP version of ungetc() * +*************************************************/ + +/* Puts a character back in the input buffer. Only ever +called once. + +Arguments: + ch the character + +Returns: the character +*/ + +int +smtp_ungetc(int ch) +{ +*--smtp_inptr = ch; +return ch; +} + + +int +bdat_ungetc(int ch) +{ +chunking_data_left++; +return lwr_receive_ungetc(ch); +} + + + +/************************************************* +* SMTP version of feof() * +*************************************************/ + +/* Tests for a previous EOF + +Arguments: none +Returns: non-zero if the eof flag is set +*/ + +int +smtp_feof(void) +{ +return smtp_had_eof; +} + + + + +/************************************************* +* SMTP version of ferror() * +*************************************************/ + +/* Tests for a previous read error, and returns with errno +restored to what it was when the error was detected. + +Arguments: none +Returns: non-zero if the error flag is set +*/ + +int +smtp_ferror(void) +{ +errno = smtp_had_error; +return smtp_had_error; +} + + + +/************************************************* +* Test for characters in the SMTP buffer * +*************************************************/ + +/* Used at the end of a message + +Arguments: none +Returns: TRUE/FALSE +*/ + +BOOL +smtp_buffered(void) +{ +return smtp_inptr < smtp_inend; +} + + + +/************************************************* +* Write formatted string to SMTP channel * +*************************************************/ + +/* This is a separate function so that we don't have to repeat everything for +TLS support or debugging. It is global so that the daemon and the +authentication functions can use it. It does not return any error indication, +because major problems such as dropped connections won't show up till an output +flush for non-TLS connections. The smtp_fflush() function is available for +checking that: for convenience, TLS output errors are remembered here so that +they are also picked up later by smtp_fflush(). + +Arguments: + format format string + more further data expected + ... optional arguments + +Returns: nothing +*/ + +void +smtp_printf(const char *format, BOOL more, ...) +{ +va_list ap; + +va_start(ap, more); +smtp_vprintf(format, more, ap); +va_end(ap); +} + +/* This is split off so that verify.c:respond_printf() can, in effect, call +smtp_printf(), bearing in mind that in C a vararg function can't directly +call another vararg function, only a function which accepts a va_list. */ + +void +smtp_vprintf(const char *format, BOOL more, va_list ap) +{ +gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer }; +BOOL yield; + +yield = !! string_vformat(&gs, FALSE, format, ap); +string_from_gstring(&gs); + +DEBUG(D_receive) + { + void *reset_point = store_get(0); + uschar *msg_copy, *cr, *end; + msg_copy = string_copy(gs.s); + end = msg_copy + gs.ptr; + while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */ + memmove(cr, cr + 1, (end--) - cr); + debug_printf("SMTP>> %s", msg_copy); + store_reset(reset_point); + } + +if (!yield) + { + log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()"); + smtp_closedown(US"Unexpected error"); + exim_exit(EXIT_FAILURE, NULL); + } + +/* If this is the first output for a (non-batch) RCPT command, see if all RCPTs +have had the same. Note: this code is also present in smtp_respond(). It would +be tidier to have it only in one place, but when it was added, it was easier to +do it that way, so as not to have to mess with the code for the RCPT command, +which sometimes uses smtp_printf() and sometimes smtp_respond(). */ + +if (fl.rcpt_in_progress) + { + if (rcpt_smtp_response == NULL) + rcpt_smtp_response = string_copy(big_buffer); + else if (fl.rcpt_smtp_response_same && + Ustrcmp(rcpt_smtp_response, big_buffer) != 0) + fl.rcpt_smtp_response_same = FALSE; + fl.rcpt_in_progress = FALSE; + } + +/* Now write the string */ + +#ifdef SUPPORT_TLS +if (tls_in.active.sock >= 0) + { + if (tls_write(NULL, gs.s, gs.ptr, more) < 0) + smtp_write_error = -1; + } +else +#endif + +if (fprintf(smtp_out, "%s", gs.s) < 0) smtp_write_error = -1; +} + + + +/************************************************* +* Flush SMTP out and check for error * +*************************************************/ + +/* This function isn't currently used within Exim (it detects errors when it +tries to read the next SMTP input), but is available for use in local_scan(). +For non-TLS connections, it flushes the output and checks for errors. For +TLS-connections, it checks for a previously-detected TLS write error. + +Arguments: none +Returns: 0 for no error; -1 after an error +*/ + +int +smtp_fflush(void) +{ +if (tls_in.active.sock < 0 && fflush(smtp_out) != 0) smtp_write_error = -1; +return smtp_write_error; +} + + + +/************************************************* +* SMTP command read timeout * +*************************************************/ + +/* Signal handler for timing out incoming SMTP commands. This attempts to +finish off tidily. + +Argument: signal number (SIGALRM) +Returns: nothing +*/ + +static void +command_timeout_handler(int sig) +{ +had_command_timeout = sig; +} + + + +/************************************************* +* SIGTERM received * +*************************************************/ + +/* Signal handler for handling SIGTERM. Again, try to finish tidily. + +Argument: signal number (SIGTERM) +Returns: nothing +*/ + +static void +command_sigterm_handler(int sig) +{ +had_command_sigterm = sig; +} + + + + +#ifdef SUPPORT_PROXY +/************************************************* +* Restore socket timeout to previous value * +*************************************************/ +/* If the previous value was successfully retrieved, restore +it before returning control to the non-proxy routines + +Arguments: fd - File descriptor for input + get_ok - Successfully retrieved previous values + tvtmp - Time struct with previous values + vslen - Length of time struct +Returns: none +*/ +static void +restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen) +{ +if (get_ok == 0) + (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen); +} + +/************************************************* +* Check if host is required proxy host * +*************************************************/ +/* The function determines if inbound host will be a regular smtp host +or if it is configured that it must use Proxy Protocol. A local +connection cannot. + +Arguments: none +Returns: bool +*/ + +static BOOL +check_proxy_protocol_host() +{ +int rc; + +if ( sender_host_address + && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL, + sender_host_address, NULL)) == OK) + { + DEBUG(D_receive) + debug_printf("Detected proxy protocol configured host\n"); + proxy_session = TRUE; + } +return proxy_session; +} + + +/************************************************* +* Read data until newline or end of buffer * +*************************************************/ +/* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't +read an entire buffer and assume there will be nothing past a proxy protocol +header. Our approach normally is to use stdio, but again that relies upon +"STARTTLS\r\n" and a server response before the client starts TLS handshake, or +reading _nothing_ before client TLS handshake. So we don't want to use the +usual buffering reads which may read enough to block TLS starting. + +So unfortunately we're down to "read one byte at a time, with a syscall each, +and expect a little overhead", for all proxy-opened connections which are v1, +just to handle the TLS-on-connect case. Since SSL functions wrap the +underlying fd, we can't assume that we can feed them any already-read content. + +We need to know where to read to, the max capacity, and we'll read until we +get a CR and one more character. Let the caller scream if it's CR+!LF. + +Return the amount read. +*/ + +static int +swallow_until_crlf(int fd, uschar *base, int already, int capacity) +{ +uschar *to = base + already; +uschar *cr; +int have = 0; +int ret; +int last = 0; + +/* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read +up through the \r; for the _normal_ case, we haven't yet seen the \r. */ + +cr = memchr(base, '\r', already); +if (cr != NULL) + { + if ((cr - base) < already - 1) + { + /* \r and presumed \n already within what we have; probably not + actually proxy protocol, but abort cleanly. */ + return 0; + } + /* \r is last character read, just need one more. */ + last = 1; + } + +while (capacity > 0) + { + do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR); + if (ret == -1) + return -1; + have++; + if (last) + return have; + if (*to == '\r') + last = 1; + capacity--; + to++; + } + +/* reached end without having room for a final newline, abort */ +errno = EOVERFLOW; +return -1; +} + +/************************************************* +* Setup host for proxy protocol * +*************************************************/ +/* The function configures the connection based on a header from the +inbound host to use Proxy Protocol. The specification is very exact +so exit with an error if do not find the exact required pieces. This +includes an incorrect number of spaces separating args. + +Arguments: none +Returns: Boolean success +*/ + +static void +setup_proxy_protocol_host() +{ +union { + struct { + uschar line[108]; + } v1; + struct { + uschar sig[12]; + uint8_t ver_cmd; + uint8_t fam; + uint16_t len; + union { + struct { /* TCP/UDP over IPv4, len = 12 */ + uint32_t src_addr; + uint32_t dst_addr; + uint16_t src_port; + uint16_t dst_port; + } ip4; + struct { /* TCP/UDP over IPv6, len = 36 */ + uint8_t src_addr[16]; + uint8_t dst_addr[16]; + uint16_t src_port; + uint16_t dst_port; + } ip6; + struct { /* AF_UNIX sockets, len = 216 */ + uschar src_addr[108]; + uschar dst_addr[108]; + } unx; + } addr; + } v2; +} hdr; + +/* Temp variables used in PPv2 address:port parsing */ +uint16_t tmpport; +char tmpip[INET_ADDRSTRLEN]; +struct sockaddr_in tmpaddr; +char tmpip6[INET6_ADDRSTRLEN]; +struct sockaddr_in6 tmpaddr6; + +/* We can't read "all data until end" because while SMTP is +server-speaks-first, the TLS handshake is client-speaks-first, so for +TLS-on-connect ports the proxy protocol header will usually be immediately +followed by a TLS handshake, and with N TLS libraries, we can't reliably +reinject data for reading by those. So instead we first read "enough to be +safely read within the header, and figure out how much more to read". +For v1 we will later read to the end-of-line, for v2 we will read based upon +the stated length. + +The v2 sig is 12 octets, and another 4 gets us the length, so we know how much +data is needed total. For v1, where the line looks like: +PROXY TCPn L3src L3dest SrcPort DestPort \r\n + +However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets. +We seem to support that. So, if we read 14 octets then we can tell if we're +v2 or v1. If we're v1, we can continue reading as normal. + +If we're v2, we can't slurp up the entire header. We need the length in the +15th & 16th octets, then to read everything after that. + +So to safely handle v1 and v2, with client-sent-first supported correctly, +we have to do a minimum of 3 read calls, not 1. Eww. +*/ + +#define PROXY_INITIAL_READ 14 +#define PROXY_V2_HEADER_SIZE 16 +#if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE +# error Code bug in sizes of data to read for proxy usage +#endif + +int get_ok = 0; +int size, ret; +int fd = fileno(smtp_in); +const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A"; +uschar * iptype; /* To display debug info */ +struct timeval tv; +struct timeval tvtmp; +socklen_t vslen = sizeof(struct timeval); +BOOL yield = FALSE; + +/* Save current socket timeout values */ +get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen); + +/* Proxy Protocol host must send header within a short time +(default 3 seconds) or it's considered invalid */ +tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC; +tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC; +if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0) + goto bad; + +do + { + /* The inbound host was declared to be a Proxy Protocol host, so + don't do a PEEK into the data, actually slurp up enough to be + "safe". Can't take it all because TLS-on-connect clients follow + immediately with TLS handshake. */ + ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0); + } + while (ret == -1 && errno == EINTR); + +if (ret == -1) + goto proxyfail; + +/* For v2, handle reading the length, and then the rest. */ +if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0)) + { + int retmore; + uint8_t ver; + + /* First get the length fields. */ + do + { + retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0); + } while (retmore == -1 && errno == EINTR); + if (retmore == -1) + goto proxyfail; + ret += retmore; + + ver = (hdr.v2.ver_cmd & 0xf0) >> 4; + + /* May 2014: haproxy combined the version and command into one byte to + allow two full bytes for the length field in order to proxy SSL + connections. SSL Proxy is not supported in this version of Exim, but + must still separate values here. */ + + if (ver != 0x02) + { + DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver); + goto proxyfail; + } + + /* The v2 header will always be 16 bytes per the spec. */ + size = 16 + ntohs(hdr.v2.len); + DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n", + size, (int)sizeof(hdr)); + + /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total + amount that we need. Double-check that the size is not unreasonable, then + get the rest. */ + if (size > sizeof(hdr)) + { + DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n"); + goto proxyfail; + } + + do + { + do + { + retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0); + } while (retmore == -1 && errno == EINTR); + if (retmore == -1) + goto proxyfail; + ret += retmore; + DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size); + } while (ret < size); + + } /* end scope for getting rest of data for v2 */ + +/* At this point: if PROXYv2, we've read the exact size required for all data; +if PROXYv1 then we've read "less than required for any valid line" and should +read the rest". */ + +if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0) + { + uint8_t cmd = (hdr.v2.ver_cmd & 0x0f); + + switch (cmd) + { + case 0x01: /* PROXY command */ + switch (hdr.v2.fam) + { + case 0x11: /* TCPv4 address type */ + iptype = US"IPv4"; + tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr; + inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip)); + if (!string_is_ip_address(US tmpip, NULL)) + { + DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype); + goto proxyfail; + } + proxy_local_address = sender_host_address; + sender_host_address = string_copy(US tmpip); + tmpport = ntohs(hdr.v2.addr.ip4.src_port); + proxy_local_port = sender_host_port; + sender_host_port = tmpport; + /* Save dest ip/port */ + tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr; + inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip)); + if (!string_is_ip_address(US tmpip, NULL)) + { + DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype); + goto proxyfail; + } + proxy_external_address = string_copy(US tmpip); + tmpport = ntohs(hdr.v2.addr.ip4.dst_port); + proxy_external_port = tmpport; + goto done; + case 0x21: /* TCPv6 address type */ + iptype = US"IPv6"; + memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16); + inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6)); + if (!string_is_ip_address(US tmpip6, NULL)) + { + DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype); + goto proxyfail; + } + proxy_local_address = sender_host_address; + sender_host_address = string_copy(US tmpip6); + tmpport = ntohs(hdr.v2.addr.ip6.src_port); + proxy_local_port = sender_host_port; + sender_host_port = tmpport; + /* Save dest ip/port */ + memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16); + inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6)); + if (!string_is_ip_address(US tmpip6, NULL)) + { + DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype); + goto proxyfail; + } + proxy_external_address = string_copy(US tmpip6); + tmpport = ntohs(hdr.v2.addr.ip6.dst_port); + proxy_external_port = tmpport; + goto done; + default: + DEBUG(D_receive) + debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n", + hdr.v2.fam); + goto proxyfail; + } + /* Unsupported protocol, keep local connection address */ + break; + case 0x00: /* LOCAL command */ + /* Keep local connection address for LOCAL */ + iptype = US"local"; + break; + default: + DEBUG(D_receive) + debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd); + goto proxyfail; + } + } +else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0) + { + uschar *p; + uschar *end; + uschar *sp; /* Utility variables follow */ + int tmp_port; + int r2; + char *endc; + + /* get the rest of the line */ + r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret); + if (r2 == -1) + goto proxyfail; + ret += r2; + + p = string_copy(hdr.v1.line); + end = memchr(p, '\r', ret - 1); + + if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n') + { + DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n"); + goto proxyfail; + } + *end = '\0'; /* Terminate the string */ + size = end + 2 - p; /* Skip header + CRLF */ + DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n"); + DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size); + /* Step through the string looking for the required fields. Ensure + strict adherence to required formatting, exit for any error. */ + p += 5; + if (!isspace(*(p++))) + { + DEBUG(D_receive) debug_printf("Missing space after PROXY command\n"); + goto proxyfail; + } + if (!Ustrncmp(p, CCS"TCP4", 4)) + iptype = US"IPv4"; + else if (!Ustrncmp(p,CCS"TCP6", 4)) + iptype = US"IPv6"; + else if (!Ustrncmp(p,CCS"UNKNOWN", 7)) + { + iptype = US"Unknown"; + goto done; + } + else + { + DEBUG(D_receive) debug_printf("Invalid TCP type\n"); + goto proxyfail; + } + + p += Ustrlen(iptype); + if (!isspace(*(p++))) + { + DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n"); + goto proxyfail; + } + /* Find the end of the arg */ + if ((sp = Ustrchr(p, ' ')) == NULL) + { + DEBUG(D_receive) + debug_printf("Did not find proxied src %s\n", iptype); + goto proxyfail; + } + *sp = '\0'; + if(!string_is_ip_address(p, NULL)) + { + DEBUG(D_receive) + debug_printf("Proxied src arg is not an %s address\n", iptype); + goto proxyfail; + } + proxy_local_address = sender_host_address; + sender_host_address = p; + p = sp + 1; + if ((sp = Ustrchr(p, ' ')) == NULL) + { + DEBUG(D_receive) + debug_printf("Did not find proxy dest %s\n", iptype); + goto proxyfail; + } + *sp = '\0'; + if(!string_is_ip_address(p, NULL)) + { + DEBUG(D_receive) + debug_printf("Proxy dest arg is not an %s address\n", iptype); + goto proxyfail; + } + proxy_external_address = p; + p = sp + 1; + if ((sp = Ustrchr(p, ' ')) == NULL) + { + DEBUG(D_receive) debug_printf("Did not find proxied src port\n"); + goto proxyfail; + } + *sp = '\0'; + tmp_port = strtol(CCS p, &endc, 10); + if (*endc || tmp_port == 0) + { + DEBUG(D_receive) + debug_printf("Proxied src port '%s' not an integer\n", p); + goto proxyfail; + } + proxy_local_port = sender_host_port; + sender_host_port = tmp_port; + p = sp + 1; + if ((sp = Ustrchr(p, '\0')) == NULL) + { + DEBUG(D_receive) debug_printf("Did not find proxy dest port\n"); + goto proxyfail; + } + tmp_port = strtol(CCS p, &endc, 10); + if (*endc || tmp_port == 0) + { + DEBUG(D_receive) + debug_printf("Proxy dest port '%s' not an integer\n", p); + goto proxyfail; + } + proxy_external_port = tmp_port; + /* Already checked for /r /n above. Good V1 header received. */ + } +else + { + /* Wrong protocol */ + DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n"); + (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret); + goto proxyfail; + } + +done: + DEBUG(D_receive) + debug_printf("Valid %s sender from Proxy Protocol header\n", iptype); + yield = proxy_session; + +/* Don't flush any potential buffer contents. Any input on proxyfail +should cause a synchronization failure */ + +proxyfail: + restore_socket_timeout(fd, get_ok, &tvtmp, vslen); + +bad: + if (yield) + { + sender_host_name = NULL; + (void) host_name_lookup(); + host_build_sender_fullhost(); + } + else + { + f.proxy_session_failed = TRUE; + DEBUG(D_receive) + debug_printf("Failure to extract proxied host, only QUIT allowed\n"); + } + +return; +} +#endif + +/************************************************* +* Read one command line * +*************************************************/ + +/* Strictly, SMTP commands coming over the net are supposed to end with CRLF. +There are sites that don't do this, and in any case internal SMTP probably +should check only for LF. Consequently, we check here for LF only. The line +ends up with [CR]LF removed from its end. If we get an overlong line, treat as +an unknown command. The command is read into the global smtp_cmd_buffer so that +it is available via $smtp_command. + +The character reading routine sets up a timeout for each block actually read +from the input (which may contain more than one command). We set up a special +signal handler that closes down the session on a timeout. Control does not +return when it runs. + +Arguments: + check_sync if TRUE, check synchronization rules if global option is TRUE + buffer_lim maximum to buffer in lower layer + +Returns: a code identifying the command (enumerated above) +*/ + +static int +smtp_read_command(BOOL check_sync, unsigned buffer_lim) +{ +int c; +int ptr = 0; +smtp_cmd_list *p; +BOOL hadnull = FALSE; + +had_command_timeout = 0; +os_non_restarting_signal(SIGALRM, command_timeout_handler); + +while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF) + { + if (ptr >= SMTP_CMD_BUFFER_SIZE) + { + os_non_restarting_signal(SIGALRM, sigalrm_handler); + return OTHER_CMD; + } + if (c == 0) + { + hadnull = TRUE; + c = '?'; + } + smtp_cmd_buffer[ptr++] = c; + } + +receive_linecount++; /* For BSMTP errors */ +os_non_restarting_signal(SIGALRM, sigalrm_handler); + +/* If hit end of file, return pseudo EOF command. Whether we have a +part-line already read doesn't matter, since this is an error state. */ + +if (c == EOF) return EOF_CMD; + +/* Remove any CR and white space at the end of the line, and terminate the +string. */ + +while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--; +smtp_cmd_buffer[ptr] = 0; + +DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer); + +/* NULLs are not allowed in SMTP commands */ + +if (hadnull) return BADCHAR_CMD; + +/* Scan command list and return identity, having set the data pointer +to the start of the actual data characters. Check for SMTP synchronization +if required. */ + +for (p = cmd_list; p < cmd_list_end; p++) + { +#ifdef SUPPORT_PROXY + /* Only allow QUIT command if Proxy Protocol parsing failed */ + if (proxy_session && f.proxy_session_failed && p->cmd != QUIT_CMD) + continue; +#endif + if ( p->len + && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 + && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */ + || smtp_cmd_buffer[p->len] == 0 + || smtp_cmd_buffer[p->len] == ' ' + ) ) + { + if (smtp_inptr < smtp_inend && /* Outstanding input */ + p->cmd < sync_cmd_limit && /* Command should sync */ + check_sync && /* Local flag set */ + smtp_enforce_sync && /* Global flag set */ + sender_host_address != NULL && /* Not local input */ + !f.sender_host_notsocket) /* Really is a socket */ + return BADSYN_CMD; + + /* The variables $smtp_command and $smtp_command_argument point into the + unmodified input buffer. A copy of the latter is taken for actual + processing, so that it can be chopped up into separate parts if necessary, + for example, when processing a MAIL command options such as SIZE that can + follow the sender address. */ + + smtp_cmd_argument = smtp_cmd_buffer + p->len; + while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++; + Ustrcpy(smtp_data_buffer, smtp_cmd_argument); + smtp_cmd_data = smtp_data_buffer; + + /* Count non-mail commands from those hosts that are controlled in this + way. The default is all hosts. We don't waste effort checking the list + until we get a non-mail command, but then cache the result to save checking + again. If there's a DEFER while checking the host, assume it's in the list. + + Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the + start of each incoming message by fiddling with the value in the table. */ + + if (!p->is_mail_cmd) + { + if (count_nonmail == TRUE_UNSET) count_nonmail = + verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL; + if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail) + return TOO_MANY_NONMAIL_CMD; + } + + /* If there is data for a command that does not expect it, generate the + error here. */ + + return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD; + } + } + +#ifdef SUPPORT_PROXY +/* Only allow QUIT command if Proxy Protocol parsing failed */ +if (proxy_session && f.proxy_session_failed) + return PROXY_FAIL_IGNORE_CMD; +#endif + +/* Enforce synchronization for unknown commands */ + +if ( smtp_inptr < smtp_inend /* Outstanding input */ + && check_sync /* Local flag set */ + && smtp_enforce_sync /* Global flag set */ + && sender_host_address /* Not local input */ + && !f.sender_host_notsocket) /* Really is a socket */ + return BADSYN_CMD; + +return OTHER_CMD; +} + + + +/************************************************* +* Forced closedown of call * +*************************************************/ + +/* This function is called from log.c when Exim is dying because of a serious +disaster, and also from some other places. If an incoming non-batched SMTP +channel is open, it swallows the rest of the incoming message if in the DATA +phase, sends the reply string, and gives an error to all subsequent commands +except QUIT. The existence of an SMTP call is detected by the non-NULLness of +smtp_in. + +Arguments: + message SMTP reply string to send, excluding the code + +Returns: nothing +*/ + +void +smtp_closedown(uschar *message) +{ +if (!smtp_in || smtp_batched_input) return; +receive_swallow_smtp(); +smtp_printf("421 %s\r\n", FALSE, message); + +for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED)) + { + case EOF_CMD: + return; + + case QUIT_CMD: + smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname); + mac_smtp_fflush(); + return; + + case RSET_CMD: + smtp_printf("250 Reset OK\r\n", FALSE); + break; + + default: + smtp_printf("421 %s\r\n", FALSE, message); + break; + } +} + + + + +/************************************************* +* Set up connection info for logging * +*************************************************/ + +/* This function is called when logging information about an SMTP connection. +It sets up appropriate source information, depending on the type of connection. +If sender_fullhost is NULL, we are at a very early stage of the connection; +just use the IP address. + +Argument: none +Returns: a string describing the connection +*/ + +uschar * +smtp_get_connection_info(void) +{ +const uschar * hostname = sender_fullhost + ? sender_fullhost : sender_host_address; + +if (host_checking) + return string_sprintf("SMTP connection from %s", hostname); + +if (f.sender_host_unknown || f.sender_host_notsocket) + return string_sprintf("SMTP connection from %s", sender_ident); + +if (f.is_inetd) + return string_sprintf("SMTP connection from %s (via inetd)", hostname); + +if (LOGGING(incoming_interface) && interface_address) + return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname, + interface_address, interface_port); + +return string_sprintf("SMTP connection from %s", hostname); +} + + + +#ifdef SUPPORT_TLS +/* Append TLS-related information to a log line + +Arguments: + g String under construction: allocated string to extend, or NULL + +Returns: Allocated string or NULL +*/ +static gstring * +s_tlslog(gstring * g) +{ +if (LOGGING(tls_cipher) && tls_in.cipher) + g = string_append(g, 2, US" X=", tls_in.cipher); +if (LOGGING(tls_certificate_verified) && tls_in.cipher) + g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no"); +if (LOGGING(tls_peerdn) && tls_in.peerdn) + g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\""); +if (LOGGING(tls_sni) && tls_in.sni) + g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\""); +return g; +} +#endif + +/************************************************* +* Log lack of MAIL if so configured * +*************************************************/ + +/* This function is called when an SMTP session ends. If the log selector +smtp_no_mail is set, write a log line giving some details of what has happened +in the SMTP session. + +Arguments: none +Returns: nothing +*/ + +void +smtp_log_no_mail(void) +{ +int i; +uschar * sep, * s; +gstring * g = NULL; + +if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail)) + return; + +if (sender_host_authenticated) + { + g = string_append(g, 2, US" A=", sender_host_authenticated); + if (authenticated_id) g = string_append(g, 2, US":", authenticated_id); + } + +#ifdef SUPPORT_TLS +g = s_tlslog(g); +#endif + +sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C="; + +for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++) + if (smtp_connection_had[i] != SCH_NONE) + { + g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]); + sep = US","; + } + +for (i = 0; i < smtp_ch_index; i++) + { + g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]); + sep = US","; + } + +if (!(s = string_from_gstring(g))) s = US""; + +log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s", + f.tcp_in_fastopen ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " : US"", + host_and_ident(FALSE), string_timesince(&smtp_connection_start), s); +} + + +/* Return list of recent smtp commands */ + +uschar * +smtp_cmd_hist(void) +{ +int i; +gstring * list = NULL; +uschar * s; + +for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++) + if (smtp_connection_had[i] != SCH_NONE) + list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]); + +for (i = 0; i < smtp_ch_index; i++) + list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]); + +s = string_from_gstring(list); +return s ? s : US""; +} + + + + +/************************************************* +* Check HELO line and set sender_helo_name * +*************************************************/ + +/* Check the format of a HELO line. The data for HELO/EHLO is supposed to be +the domain name of the sending host, or an ip literal in square brackets. The +argument is placed in sender_helo_name, which is in malloc store, because it +must persist over multiple incoming messages. If helo_accept_junk is set, this +host is permitted to send any old junk (needed for some broken hosts). +Otherwise, helo_allow_chars can be used for rogue characters in general +(typically people want to let in underscores). + +Argument: + s the data portion of the line (already past any white space) + +Returns: TRUE or FALSE +*/ + +static BOOL +check_helo(uschar *s) +{ +uschar *start = s; +uschar *end = s + Ustrlen(s); +BOOL yield = fl.helo_accept_junk; + +/* Discard any previous helo name */ + +if (sender_helo_name) + { + store_free(sender_helo_name); + sender_helo_name = NULL; + } + +/* Skip tests if junk is permitted. */ + +if (!yield) + + /* Allow the new standard form for IPv6 address literals, namely, + [IPv6:....], and because someone is bound to use it, allow an equivalent + IPv4 form. Allow plain addresses as well. */ + + if (*s == '[') + { + if (end[-1] == ']') + { + end[-1] = 0; + if (strncmpic(s, US"[IPv6:", 6) == 0) + yield = (string_is_ip_address(s+6, NULL) == 6); + else if (strncmpic(s, US"[IPv4:", 6) == 0) + yield = (string_is_ip_address(s+6, NULL) == 4); + else + yield = (string_is_ip_address(s+1, NULL) != 0); + end[-1] = ']'; + } + } + + /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars + that have been configured (usually underscore - sigh). */ + + else if (*s) + for (yield = TRUE; *s; s++) + if (!isalnum(*s) && *s != '.' && *s != '-' && + Ustrchr(helo_allow_chars, *s) == NULL) + { + yield = FALSE; + break; + } + +/* Save argument if OK */ + +if (yield) sender_helo_name = string_copy_malloc(start); +return yield; +} + + + + + +/************************************************* +* Extract SMTP command option * +*************************************************/ + +/* This function picks the next option setting off the end of smtp_cmd_data. It +is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP +things that can appear there. + +Arguments: + name point this at the name + value point this at the data string + +Returns: TRUE if found an option +*/ + +static BOOL +extract_option(uschar **name, uschar **value) +{ +uschar *n; +uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1; +while (isspace(*v)) v--; +v[1] = 0; +while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) + { + /* Take care to not stop at a space embedded in a quoted local-part */ + + if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1); + v--; + } + +n = v; +if (*v == '=') + { + while(isalpha(n[-1])) n--; + /* RFC says SP, but TAB seen in wild and other major MTAs accept it */ + if (!isspace(n[-1])) return FALSE; + n[-1] = 0; + } +else + { + n++; + if (v == smtp_cmd_data) return FALSE; + } +*v++ = 0; +*name = n; +*value = v; +return TRUE; +} + + + + + +/************************************************* +* Reset for new message * +*************************************************/ + +/* This function is called whenever the SMTP session is reset from +within either of the setup functions; also from the daemon loop. + +Argument: the stacking pool storage reset point +Returns: nothing +*/ + +void +smtp_reset(void *reset_point) +{ +recipients_list = NULL; +rcpt_count = rcpt_defer_count = rcpt_fail_count = + raw_recipients_count = recipients_count = recipients_list_max = 0; +message_linecount = 0; +message_size = -1; +acl_added_headers = NULL; +acl_removed_headers = NULL; +f.queue_only_policy = FALSE; +rcpt_smtp_response = NULL; +fl.rcpt_smtp_response_same = TRUE; +fl.rcpt_in_progress = FALSE; +f.deliver_freeze = FALSE; /* Can be set by ACL */ +freeze_tell = freeze_tell_config; /* Can be set by ACL */ +fake_response = OK; /* Can be set by ACL */ +#ifdef WITH_CONTENT_SCAN +f.no_mbox_unspool = FALSE; /* Can be set by ACL */ +#endif +f.submission_mode = FALSE; /* Can be set by ACL */ +f.suppress_local_fixups = f.suppress_local_fixups_default; /* Can be set by ACL */ +f.active_local_from_check = local_from_check; /* Can be set by ACL */ +f.active_local_sender_retain = local_sender_retain; /* Can be set by ACL */ +sending_ip_address = NULL; +return_path = sender_address = NULL; +sender_data = NULL; /* Can be set by ACL */ +deliver_localpart_parent = deliver_localpart_orig = NULL; +deliver_domain_parent = deliver_domain_orig = NULL; +callout_address = NULL; +submission_name = NULL; /* Can be set by ACL */ +raw_sender = NULL; /* After SMTP rewrite, before qualifying */ +sender_address_unrewritten = NULL; /* Set only after verify rewrite */ +sender_verified_list = NULL; /* No senders verified */ +memset(sender_address_cache, 0, sizeof(sender_address_cache)); +memset(sender_domain_cache, 0, sizeof(sender_domain_cache)); + +authenticated_sender = NULL; +#ifdef EXPERIMENTAL_BRIGHTMAIL +bmi_run = 0; +bmi_verdicts = NULL; +#endif +dnslist_domain = dnslist_matched = NULL; +#ifdef SUPPORT_SPF +spf_header_comment = spf_received = spf_result = spf_smtp_comment = NULL; +spf_result_guessed = FALSE; +#endif +#ifndef DISABLE_DKIM +dkim_cur_signer = dkim_signers = +dkim_signing_domain = dkim_signing_selector = dkim_signatures = NULL; +dkim_cur_signer = dkim_signers = dkim_signing_domain = dkim_signing_selector = NULL; +f.dkim_disable_verify = FALSE; +dkim_collect_input = 0; +dkim_verify_overall = dkim_verify_status = dkim_verify_reason = NULL; +dkim_key_length = 0; +#endif +#ifdef EXPERIMENTAL_DMARC +f.dmarc_has_been_checked = f.dmarc_disable_verify = f.dmarc_enable_forensic = FALSE; +dmarc_domain_policy = dmarc_status = dmarc_status_text = +dmarc_used_domain = NULL; +#endif +#ifdef EXPERIMENTAL_ARC +arc_state = arc_state_reason = NULL; +#endif +dsn_ret = 0; +dsn_envid = NULL; +deliver_host = deliver_host_address = NULL; /* Can be set by ACL */ +#ifndef DISABLE_PRDR +prdr_requested = FALSE; +#endif +#ifdef SUPPORT_I18N +message_smtputf8 = FALSE; +#endif +body_linecount = body_zerocount = 0; + +sender_rate = sender_rate_limit = sender_rate_period = NULL; +ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */ + /* Note that ratelimiters_conn persists across resets. */ + +/* Reset message ACL variables */ + +acl_var_m = NULL; + +/* The message body variables use malloc store. They may be set if this is +not the first message in an SMTP session and the previous message caused them +to be referenced in an ACL. */ + +if (message_body) + { + store_free(message_body); + message_body = NULL; + } + +if (message_body_end) + { + store_free(message_body_end); + message_body_end = NULL; + } + +/* Warning log messages are also saved in malloc store. They are saved to avoid +repetition in the same message, but it seems right to repeat them for different +messages. */ + +while (acl_warn_logged) + { + string_item *this = acl_warn_logged; + acl_warn_logged = acl_warn_logged->next; + store_free(this); + } +store_reset(reset_point); +} + + + + + +/************************************************* +* Initialize for incoming batched SMTP message * +*************************************************/ + +/* This function is called from smtp_setup_msg() in the case when +smtp_batched_input is true. This happens when -bS is used to pass a whole batch +of messages in one file with SMTP commands between them. All errors must be +reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are +relevant. After an error on a sender, or an invalid recipient, the remainder +of the message is skipped. The value of received_protocol is already set. + +Argument: none +Returns: > 0 message successfully started (reached DATA) + = 0 QUIT read or end of file reached + < 0 should not occur +*/ + +static int +smtp_setup_batch_msg(void) +{ +int done = 0; +void *reset_point = store_get(0); + +/* Save the line count at the start of each transaction - single commands +like HELO and RSET count as whole transactions. */ + +bsmtp_transaction_linecount = receive_linecount; + +if ((receive_feof)()) return 0; /* Treat EOF as QUIT */ + +cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg"); +smtp_reset(reset_point); /* Reset for start of message */ + +/* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE +value. The values are 2 larger than the required yield of the function. */ + +while (done <= 0) + { + uschar *errmess; + uschar *recipient = NULL; + int start, end, sender_domain, recipient_domain; + + switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED)) + { + /* The HELO/EHLO commands set sender_address_helo if they have + valid data; otherwise they are ignored, except that they do + a reset of the state. */ + + case HELO_CMD: + case EHLO_CMD: + + check_helo(smtp_cmd_data); + /* Fall through */ + + case RSET_CMD: + cancel_cutthrough_connection(TRUE, US"RSET received"); + smtp_reset(reset_point); + bsmtp_transaction_linecount = receive_linecount; + break; + + + /* The MAIL FROM command requires an address as an operand. All we + do here is to parse it for syntactic correctness. The form "<>" is + a special case which converts into an empty string. The start/end + pointers in the original are not used further for this address, as + it is the canonical extracted address which is all that is kept. */ + + case MAIL_CMD: + smtp_mailcmd_count++; /* Count for no-mail log */ + if (sender_address != NULL) + /* The function moan_smtp_batch() does not return. */ + moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given"); + + if (smtp_cmd_data[0] == 0) + /* The function moan_smtp_batch() does not return. */ + moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand"); + + /* Reset to start of message */ + + cancel_cutthrough_connection(TRUE, US"MAIL received"); + smtp_reset(reset_point); + + /* Apply SMTP rewrite */ + + raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)? + rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE, + US"", global_rewrite_rules) : smtp_cmd_data; + + /* Extract the address; the TRUE flag allows <> as valid */ + + raw_sender = + parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain, + TRUE); + + if (!raw_sender) + /* The function moan_smtp_batch() does not return. */ + moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess); + + sender_address = string_copy(raw_sender); + + /* Qualify unqualified sender addresses if permitted to do so. */ + + if ( !sender_domain + && sender_address[0] != 0 && sender_address[0] != '@') + if (f.allow_unqualified_sender) + { + sender_address = rewrite_address_qualify(sender_address, FALSE); + DEBUG(D_receive) debug_printf("unqualified address %s accepted " + "and rewritten\n", raw_sender); + } + /* The function moan_smtp_batch() does not return. */ + else + moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain " + "a domain"); + break; + + + /* The RCPT TO command requires an address as an operand. All we do + here is to parse it for syntactic correctness. There may be any number + of RCPT TO commands, specifying multiple senders. We build them all into + a data structure that is in argc/argv format. The start/end values + given by parse_extract_address are not used, as we keep only the + extracted address. */ + + case RCPT_CMD: + if (!sender_address) + /* The function moan_smtp_batch() does not return. */ + moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given"); + + if (smtp_cmd_data[0] == 0) + /* The function moan_smtp_batch() does not return. */ + moan_smtp_batch(smtp_cmd_buffer, + "501 RCPT TO must have an address operand"); + + /* Check maximum number allowed */ + + if (recipients_max > 0 && recipients_count + 1 > recipients_max) + /* The function moan_smtp_batch() does not return. */ + moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients", + recipients_max_reject? "552": "452"); + + /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a + recipient address */ + + recipient = rewrite_existflags & rewrite_smtp + ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"", + global_rewrite_rules) + : smtp_cmd_data; + + recipient = parse_extract_address(recipient, &errmess, &start, &end, + &recipient_domain, FALSE); + + if (!recipient) + /* The function moan_smtp_batch() does not return. */ + moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess); + + /* If the recipient address is unqualified, qualify it if permitted. Then + add it to the list of recipients. */ + + if (!recipient_domain) + if (f.allow_unqualified_recipient) + { + DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", + recipient); + recipient = rewrite_address_qualify(recipient, TRUE); + } + /* The function moan_smtp_batch() does not return. */ + else + moan_smtp_batch(smtp_cmd_buffer, + "501 recipient address must contain a domain"); + + receive_add_recipient(recipient, -1); + break; + + + /* The DATA command is legal only if it follows successful MAIL FROM + and RCPT TO commands. This function is complete when a valid DATA + command is encountered. */ + + case DATA_CMD: + if (!sender_address || recipients_count <= 0) + /* The function moan_smtp_batch() does not return. */ + if (!sender_address) + moan_smtp_batch(smtp_cmd_buffer, + "503 MAIL FROM:<sender> command must precede DATA"); + else + moan_smtp_batch(smtp_cmd_buffer, + "503 RCPT TO:<recipient> must precede DATA"); + else + { + done = 3; /* DATA successfully achieved */ + message_ended = END_NOTENDED; /* Indicate in middle of message */ + } + break; + + + /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */ + + case VRFY_CMD: + case EXPN_CMD: + case HELP_CMD: + case NOOP_CMD: + case ETRN_CMD: + bsmtp_transaction_linecount = receive_linecount; + break; + + + case EOF_CMD: + case QUIT_CMD: + done = 2; + break; + + + case BADARG_CMD: + /* The function moan_smtp_batch() does not return. */ + moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data"); + break; + + + case BADCHAR_CMD: + /* The function moan_smtp_batch() does not return. */ + moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command"); + break; + + + default: + /* The function moan_smtp_batch() does not return. */ + moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized"); + break; + } + } + +return done - 2; /* Convert yield values */ +} + + + + +#ifdef SUPPORT_TLS +static BOOL +smtp_log_tls_fail(uschar * errstr) +{ +uschar * conn_info = smtp_get_connection_info(); + +if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5; +/* I'd like to get separated H= here, but too hard for now */ + +log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr); +return FALSE; +} +#endif + + + + +#ifdef TCP_FASTOPEN +static void +tfo_in_check(void) +{ +# ifdef TCP_INFO +struct tcp_info tinfo; +socklen_t len = sizeof(tinfo); + +if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0) +#ifdef TCPI_OPT_SYN_DATA /* FreeBSD 11 does not seem to have this yet */ + if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA) + { + DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (ACKd data-on-SYN)\n"); + f.tcp_in_fastopen_data = f.tcp_in_fastopen = TRUE; + } + else +#endif + if (tinfo.tcpi_state == TCP_SYN_RECV) + { + DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n"); + f.tcp_in_fastopen = TRUE; + } +# endif +} +#endif + + +/************************************************* +* Start an SMTP session * +*************************************************/ + +/* This function is called at the start of an SMTP session. Thereafter, +smtp_setup_msg() is called to initiate each separate message. This +function does host-specific testing, and outputs the banner line. + +Arguments: none +Returns: FALSE if the session can not continue; something has + gone wrong, or the connection to the host is blocked +*/ + +BOOL +smtp_start_session(void) +{ +int esclen; +uschar *user_msg, *log_msg; +uschar *code, *esc; +uschar *p, *s; +gstring * ss; + +gettimeofday(&smtp_connection_start, NULL); +for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++) + smtp_connection_had[smtp_ch_index] = SCH_NONE; +smtp_ch_index = 0; + +/* Default values for certain variables */ + +fl.helo_seen = fl.esmtp = fl.helo_accept_junk = FALSE; +smtp_mailcmd_count = 0; +count_nonmail = TRUE_UNSET; +synprot_error_count = unknown_command_count = nonmail_command_count = 0; +smtp_delay_mail = smtp_rlm_base; +fl.auth_advertised = FALSE; +f.smtp_in_pipelining_advertised = f.smtp_in_pipelining_used = FALSE; +f.pipelining_enable = TRUE; +sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING; +fl.smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */ + +/* If receiving by -bs from a trusted user, or testing with -bh, we allow +authentication settings from -oMaa to remain in force. */ + +if (!host_checking && !f.sender_host_notsocket) + sender_host_auth_pubname = sender_host_authenticated = NULL; +authenticated_by = NULL; + +#ifdef SUPPORT_TLS +tls_in.cipher = tls_in.peerdn = NULL; +tls_in.ourcert = tls_in.peercert = NULL; +tls_in.sni = NULL; +tls_in.ocsp = OCSP_NOT_REQ; +fl.tls_advertised = FALSE; +# ifdef EXPERIMENTAL_REQUIRETLS +fl.requiretls_advertised = FALSE; +# endif +#endif +fl.dsn_advertised = FALSE; +#ifdef SUPPORT_I18N +fl.smtputf8_advertised = FALSE; +#endif + +/* Reset ACL connection variables */ + +acl_var_c = NULL; + +/* Allow for trailing 0 in the command and data buffers. */ + +if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2))) + log_write(0, LOG_MAIN|LOG_PANIC_DIE, + "malloc() failed for SMTP command buffer"); + +smtp_cmd_buffer[0] = 0; +smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1; + +/* For batched input, the protocol setting can be overridden from the +command line by a trusted caller. */ + +if (smtp_batched_input) + { + if (!received_protocol) received_protocol = US"local-bsmtp"; + } + +/* For non-batched SMTP input, the protocol setting is forced here. It will be +reset later if any of EHLO/AUTH/STARTTLS are received. */ + +else + received_protocol = + (sender_host_address ? protocols : protocols_local) [pnormal]; + +/* Set up the buffer for inputting using direct read() calls, and arrange to +call the local functions instead of the standard C ones. Place a NUL at the +end of the buffer to safety-stop C-string reads from it. */ + +if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE))) + log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer"); +smtp_inbuffer[IN_BUFFER_SIZE-1] = '\0'; + +receive_getc = smtp_getc; +receive_getbuf = smtp_getbuf; +receive_get_cache = smtp_get_cache; +receive_ungetc = smtp_ungetc; +receive_feof = smtp_feof; +receive_ferror = smtp_ferror; +receive_smtp_buffered = smtp_buffered; +smtp_inptr = smtp_inend = smtp_inbuffer; +smtp_had_eof = smtp_had_error = 0; + +/* Set up the message size limit; this may be host-specific */ + +thismessage_size_limit = expand_string_integer(message_size_limit, TRUE); +if (expand_string_message) + { + if (thismessage_size_limit == -1) + log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: " + "%s", expand_string_message); + else + log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: " + "%s", expand_string_message); + smtp_closedown(US"Temporary local problem - please try later"); + return FALSE; + } + +/* When a message is input locally via the -bs or -bS options, sender_host_ +unknown is set unless -oMa was used to force an IP address, in which case it +is checked like a real remote connection. When -bs is used from inetd, this +flag is not set, causing the sending host to be checked. The code that deals +with IP source routing (if configured) is never required for -bs or -bS and +the flag sender_host_notsocket is used to suppress it. + +If smtp_accept_max and smtp_accept_reserve are set, keep some connections in +reserve for certain hosts and/or networks. */ + +if (!f.sender_host_unknown) + { + int rc; + BOOL reserved_host = FALSE; + + /* Look up IP options (source routing info) on the socket if this is not an + -oMa "host", and if any are found, log them and drop the connection. + + Linux (and others now, see below) is different to everyone else, so there + has to be some conditional compilation here. Versions of Linux before 2.1.15 + used a structure whose name was "options". Somebody finally realized that + this name was silly, and it got changed to "ip_options". I use the + newer name here, but there is a fudge in the script that sets up os.h + to define a macro in older Linux systems. + + Sigh. Linux is a fast-moving target. Another generation of Linux uses + glibc 2, which has chosen ip_opts for the structure name. This is now + really a glibc thing rather than a Linux thing, so the condition name + has been changed to reflect this. It is relevant also to GNU/Hurd. + + Mac OS 10.x (Darwin) is like the later glibc versions, but without the + setting of the __GLIBC__ macro, so we can't detect it automatically. There's + a special macro defined in the os.h file. + + Some DGUX versions on older hardware appear not to support IP options at + all, so there is now a general macro which can be set to cut out this + support altogether. + + How to do this properly in IPv6 is not yet known. */ + +#if !HAVE_IPV6 && !defined(NO_IP_OPTIONS) + + #ifdef GLIBC_IP_OPTIONS + #if (!defined __GLIBC__) || (__GLIBC__ < 2) + #define OPTSTYLE 1 + #else + #define OPTSTYLE 2 + #endif + #elif defined DARWIN_IP_OPTIONS + #define OPTSTYLE 2 + #else + #define OPTSTYLE 3 + #endif + + if (!host_checking && !f.sender_host_notsocket) + { + #if OPTSTYLE == 1 + EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN; + struct ip_options *ipopt = store_get(optlen); + #elif OPTSTYLE == 2 + struct ip_opts ipoptblock; + struct ip_opts *ipopt = &ipoptblock; + EXIM_SOCKLEN_T optlen = sizeof(ipoptblock); + #else + struct ipoption ipoptblock; + struct ipoption *ipopt = &ipoptblock; + EXIM_SOCKLEN_T optlen = sizeof(ipoptblock); + #endif + + /* Occasional genuine failures of getsockopt() have been seen - for + example, "reset by peer". Therefore, just log and give up on this + call, unless the error is ENOPROTOOPT. This error is given by systems + that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time + of writing. So for that error, carry on - we just can't do an IP options + check. */ + + DEBUG(D_receive) debug_printf("checking for IP options\n"); + + if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt), + &optlen) < 0) + { + if (errno != ENOPROTOOPT) + { + log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s", + host_and_ident(FALSE), strerror(errno)); + smtp_printf("451 SMTP service not available\r\n", FALSE); + return FALSE; + } + } + + /* Deal with any IP options that are set. On the systems I have looked at, + the value of MAX_IPOPTLEN has been 40, meaning that there should never be + more logging data than will fit in big_buffer. Nevertheless, after somebody + questioned this code, I've added in some paranoid checking. */ + + else if (optlen > 0) + { + uschar *p = big_buffer; + uschar *pend = big_buffer + big_buffer_size; + uschar *opt, *adptr; + int optcount; + struct in_addr addr; + + #if OPTSTYLE == 1 + uschar *optstart = US (ipopt->__data); + #elif OPTSTYLE == 2 + uschar *optstart = US (ipopt->ip_opts); + #else + uschar *optstart = US (ipopt->ipopt_list); + #endif + + DEBUG(D_receive) debug_printf("IP options exist\n"); + + Ustrcpy(p, "IP options on incoming call:"); + p += Ustrlen(p); + + for (opt = optstart; opt != NULL && + opt < US (ipopt) + optlen;) + { + switch (*opt) + { + case IPOPT_EOL: + opt = NULL; + break; + + case IPOPT_NOP: + opt++; + break; + + case IPOPT_SSRR: + case IPOPT_LSRR: + if (!string_format(p, pend-p, " %s [@%s", + (*opt == IPOPT_SSRR)? "SSRR" : "LSRR", + #if OPTSTYLE == 1 + inet_ntoa(*((struct in_addr *)(&(ipopt->faddr)))))) + #elif OPTSTYLE == 2 + inet_ntoa(ipopt->ip_dst))) + #else + inet_ntoa(ipopt->ipopt_dst))) + #endif + { + opt = NULL; + break; + } + + p += Ustrlen(p); + optcount = (opt[1] - 3) / sizeof(struct in_addr); + adptr = opt + 3; + while (optcount-- > 0) + { + memcpy(&addr, adptr, sizeof(addr)); + if (!string_format(p, pend - p - 1, "%s%s", + (optcount == 0)? ":" : "@", inet_ntoa(addr))) + { + opt = NULL; + break; + } + p += Ustrlen(p); + adptr += sizeof(struct in_addr); + } + *p++ = ']'; + opt += opt[1]; + break; + + default: + { + int i; + if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; } + Ustrcat(p, "[ "); + p += 2; + for (i = 0; i < opt[1]; i++) + p += sprintf(CS p, "%2.2x ", opt[i]); + *p++ = ']'; + } + opt += opt[1]; + break; + } + } + + *p = 0; + log_write(0, LOG_MAIN, "%s", big_buffer); + + /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */ + + log_write(0, LOG_MAIN|LOG_REJECT, + "connection from %s refused (IP options)", host_and_ident(FALSE)); + + smtp_printf("554 SMTP service not available\r\n", FALSE); + return FALSE; + } + + /* Length of options = 0 => there are no options */ + + else DEBUG(D_receive) debug_printf("no IP options found\n"); + } +#endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */ + + /* Set keep-alive in socket options. The option is on by default. This + setting is an attempt to get rid of some hanging connections that stick in + read() when the remote end (usually a dialup) goes away. */ + + if (smtp_accept_keepalive && !f.sender_host_notsocket) + ip_keepalive(fileno(smtp_out), sender_host_address, FALSE); + + /* If the current host matches host_lookup, set the name by doing a + reverse lookup. On failure, sender_host_name will be NULL and + host_lookup_failed will be TRUE. This may or may not be serious - optional + checks later. */ + + if (verify_check_host(&host_lookup) == OK) + { + (void)host_name_lookup(); + host_build_sender_fullhost(); + } + + /* Delay this until we have the full name, if it is looked up. */ + + set_process_info("handling incoming connection from %s", + host_and_ident(FALSE)); + + /* Expand smtp_receive_timeout, if needed */ + + if (smtp_receive_timeout_s) + { + uschar * exp; + if ( !(exp = expand_string(smtp_receive_timeout_s)) + || !(*exp) + || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0 + ) + log_write(0, LOG_MAIN|LOG_PANIC, + "bad value for smtp_receive_timeout: '%s'", exp ? exp : US""); + } + + /* Test for explicit connection rejection */ + + if (verify_check_host(&host_reject_connection) == OK) + { + log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection " + "from %s (host_reject_connection)", host_and_ident(FALSE)); + smtp_printf("554 SMTP service not available\r\n", FALSE); + return FALSE; + } + + /* Test with TCP Wrappers if so configured. There is a problem in that + hosts_ctl() returns 0 (deny) under a number of system failure circumstances, + such as disks dying. In these cases, it is desirable to reject with a 4xx + error instead of a 5xx error. There isn't a "right" way to detect such + problems. The following kludge is used: errno is zeroed before calling + hosts_ctl(). If the result is "reject", a 5xx error is given only if the + value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does + not exist). */ + +#ifdef USE_TCP_WRAPPERS + errno = 0; + if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name))) + log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" " + "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name), + expand_string_message); + + if (!hosts_ctl(tcp_wrappers_name, + sender_host_name ? CS sender_host_name : STRING_UNKNOWN, + sender_host_address ? CS sender_host_address : STRING_UNKNOWN, + sender_ident ? CS sender_ident : STRING_UNKNOWN)) + { + if (errno == 0 || errno == ENOENT) + { + HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n"); + log_write(L_connection_reject, + LOG_MAIN|LOG_REJECT, "refused connection from %s " + "(tcp wrappers)", host_and_ident(FALSE)); + smtp_printf("554 SMTP service not available\r\n", FALSE); + } + else + { + int save_errno = errno; + HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected " + "errno value %d\n", save_errno); + log_write(L_connection_reject, + LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s " + "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno); + smtp_printf("451 Temporary local problem - please try later\r\n", FALSE); + } + return FALSE; + } +#endif + + /* Check for reserved slots. The value of smtp_accept_count has already been + incremented to include this process. */ + + if (smtp_accept_max > 0 && + smtp_accept_count > smtp_accept_max - smtp_accept_reserve) + { + if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK) + { + log_write(L_connection_reject, + LOG_MAIN, "temporarily refused connection from %s: not in " + "reserve list: connected=%d max=%d reserve=%d%s", + host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max, + smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : ""); + smtp_printf("421 %s: Too many concurrent SMTP connections; " + "please try again later\r\n", FALSE, smtp_active_hostname); + return FALSE; + } + reserved_host = TRUE; + } + + /* If a load level above which only messages from reserved hosts are + accepted is set, check the load. For incoming calls via the daemon, the + check is done in the superior process if there are no reserved hosts, to + save a fork. In all cases, the load average will already be available + in a global variable at this point. */ + + if (smtp_load_reserve >= 0 && + load_average > smtp_load_reserve && + !reserved_host && + verify_check_host(&smtp_reserve_hosts) != OK) + { + log_write(L_connection_reject, + LOG_MAIN, "temporarily refused connection from %s: not in " + "reserve list and load average = %.2f", host_and_ident(FALSE), + (double)load_average/1000.0); + smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE, + smtp_active_hostname); + return FALSE; + } + + /* Determine whether unqualified senders or recipients are permitted + for this host. Unfortunately, we have to do this every time, in order to + set the flags so that they can be inspected when considering qualifying + addresses in the headers. For a site that permits no qualification, this + won't take long, however. */ + + f.allow_unqualified_sender = + verify_check_host(&sender_unqualified_hosts) == OK; + + f.allow_unqualified_recipient = + verify_check_host(&recipient_unqualified_hosts) == OK; + + /* Determine whether HELO/EHLO is required for this host. The requirement + can be hard or soft. */ + + fl.helo_required = verify_check_host(&helo_verify_hosts) == OK; + if (!fl.helo_required) + fl.helo_verify = verify_check_host(&helo_try_verify_hosts) == OK; + + /* Determine whether this hosts is permitted to send syntactic junk + after a HELO or EHLO command. */ + + fl.helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK; + } + +/* For batch SMTP input we are now done. */ + +if (smtp_batched_input) return TRUE; + +/* If valid Proxy Protocol source is connecting, set up session. + * Failure will not allow any SMTP function other than QUIT. */ + +#ifdef SUPPORT_PROXY +proxy_session = FALSE; +f.proxy_session_failed = FALSE; +if (check_proxy_protocol_host()) + setup_proxy_protocol_host(); +#endif + + /* Start up TLS if tls_on_connect is set. This is for supporting the legacy + smtps port for use with older style SSL MTAs. */ + +#ifdef SUPPORT_TLS + if (tls_in.on_connect) + { + if (tls_server_start(tls_require_ciphers, &user_msg) != OK) + return smtp_log_tls_fail(user_msg); + cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE; + } +#endif + +/* Run the connect ACL if it exists */ + +user_msg = NULL; +if (acl_smtp_connect) + { + int rc; + if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg, + &log_msg)) != OK) + { + (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg); + return FALSE; + } + } + +/* Output the initial message for a two-way SMTP connection. It may contain +newlines, which then cause a multi-line response to be given. */ + +code = US"220"; /* Default status code */ +esc = US""; /* Default extended status code */ +esclen = 0; /* Length of esc */ + +if (!user_msg) + { + if (!(s = expand_string(smtp_banner))) + log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) " + "failed: %s", smtp_banner, expand_string_message); + } +else + { + int codelen = 3; + s = user_msg; + smtp_message_code(&code, &codelen, &s, NULL, TRUE); + if (codelen > 4) + { + esc = code + 4; + esclen = codelen - 4; + } + } + +/* Remove any terminating newlines; might as well remove trailing space too */ + +p = s + Ustrlen(s); +while (p > s && isspace(p[-1])) p--; +*p = 0; + +/* It seems that CC:Mail is braindead, and assumes that the greeting message +is all contained in a single IP packet. The original code wrote out the +greeting using several calls to fprint/fputc, and on busy servers this could +cause it to be split over more than one packet - which caused CC:Mail to fall +over when it got the second part of the greeting after sending its first +command. Sigh. To try to avoid this, build the complete greeting message +first, and output it in one fell swoop. This gives a better chance of it +ending up as a single packet. */ + +ss = string_get(256); + +p = s; +do /* At least once, in case we have an empty string */ + { + int len; + uschar *linebreak = Ustrchr(p, '\n'); + ss = string_catn(ss, code, 3); + if (!linebreak) + { + len = Ustrlen(p); + ss = string_catn(ss, US" ", 1); + } + else + { + len = linebreak - p; + ss = string_catn(ss, US"-", 1); + } + ss = string_catn(ss, esc, esclen); + ss = string_catn(ss, p, len); + ss = string_catn(ss, US"\r\n", 2); + p += len; + if (linebreak) p++; + } +while (*p); + +/* Before we write the banner, check that there is no input pending, unless +this synchronisation check is disabled. */ + +#ifdef EXPERIMENTAL_PIPE_CONNECT +fl.pipe_connect_acceptable = + sender_host_address && verify_check_host(&pipe_connect_advertise_hosts) == OK; + +if (!check_sync()) + if (fl.pipe_connect_acceptable) + f.smtp_in_early_pipe_used = TRUE; + else +#else +if (!check_sync()) +#endif + { + unsigned n = smtp_inend - smtp_inptr; + if (n > 32) n = 32; + + log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol " + "synchronization error (input sent without waiting for greeting): " + "rejected connection from %s input=\"%s\"", host_and_ident(TRUE), + string_printing(string_copyn(smtp_inptr, n))); + smtp_printf("554 SMTP synchronization error\r\n", FALSE); + return FALSE; + } + +/* Now output the banner */ +/*XXX the ehlo-resp code does its own tls/nontls bit. Maybe subroutine that? */ + +smtp_printf("%s", +#ifdef EXPERIMENTAL_PIPE_CONNECT + fl.pipe_connect_acceptable && pipeline_connect_sends(), +#else + FALSE, +#endif + string_from_gstring(ss)); + +/* Attempt to see if we sent the banner before the last ACK of the 3-way +handshake arrived. If so we must have managed a TFO. */ + +#ifdef TCP_FASTOPEN +tfo_in_check(); +#endif + +return TRUE; +} + + + + + +/************************************************* +* Handle SMTP syntax and protocol errors * +*************************************************/ + +/* Write to the log for SMTP syntax errors in incoming commands, if configured +to do so. Then transmit the error response. The return value depends on the +number of syntax and protocol errors in this SMTP session. + +Arguments: + type error type, given as a log flag bit + code response code; <= 0 means don't send a response + data data to reflect in the response (can be NULL) + errmess the error message + +Returns: -1 limit of syntax/protocol errors NOT exceeded + +1 limit of syntax/protocol errors IS exceeded + +These values fit in with the values of the "done" variable in the main +processing loop in smtp_setup_msg(). */ + +static int +synprot_error(int type, int code, uschar *data, uschar *errmess) +{ +int yield = -1; + +log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s", + (type == L_smtp_syntax_error)? "syntax" : "protocol", + string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess); + +if (++synprot_error_count > smtp_max_synprot_errors) + { + yield = 1; + log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " + "syntax or protocol errors (last command was \"%s\")", + host_and_ident(FALSE), string_printing(smtp_cmd_buffer)); + } + +if (code > 0) + { + smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ', + data ? data : US"", data ? US": " : US"", errmess); + if (yield == 1) + smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code); + } + +return yield; +} + + + + +/************************************************* +* Send SMTP response, possibly multiline * +*************************************************/ + +/* There are, it seems, broken clients out there that cannot handle multiline +responses. If no_multiline_responses is TRUE (it can be set from an ACL), we +output nothing for non-final calls, and only the first line for anything else. + +Arguments: + code SMTP code, may involve extended status codes + codelen length of smtp code; if > 4 there's an ESC + final FALSE if the last line isn't the final line + msg message text, possibly containing newlines + +Returns: nothing +*/ + +void +smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg) +{ +int esclen = 0; +uschar *esc = US""; + +if (!final && f.no_multiline_responses) return; + +if (codelen > 4) + { + esc = code + 4; + esclen = codelen - 4; + } + +/* If this is the first output for a (non-batch) RCPT command, see if all RCPTs +have had the same. Note: this code is also present in smtp_printf(). It would +be tidier to have it only in one place, but when it was added, it was easier to +do it that way, so as not to have to mess with the code for the RCPT command, +which sometimes uses smtp_printf() and sometimes smtp_respond(). */ + +if (fl.rcpt_in_progress) + { + if (rcpt_smtp_response == NULL) + rcpt_smtp_response = string_copy(msg); + else if (fl.rcpt_smtp_response_same && + Ustrcmp(rcpt_smtp_response, msg) != 0) + fl.rcpt_smtp_response_same = FALSE; + fl.rcpt_in_progress = FALSE; + } + +/* Now output the message, splitting it up into multiple lines if necessary. +We only handle pipelining these responses as far as nonfinal/final groups, +not the whole MAIL/RCPT/DATA response set. */ + +for (;;) + { + uschar *nl = Ustrchr(msg, '\n'); + if (nl == NULL) + { + smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg); + return; + } + else if (nl[1] == 0 || f.no_multiline_responses) + { + smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc, + (int)(nl - msg), msg); + return; + } + else + { + smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg); + msg = nl + 1; + while (isspace(*msg)) msg++; + } + } +} + + + + +/************************************************* +* Parse user SMTP message * +*************************************************/ + +/* This function allows for user messages overriding the response code details +by providing a suitable response code string at the start of the message +user_msg. Check the message for starting with a response code and optionally an +extended status code. If found, check that the first digit is valid, and if so, +change the code pointer and length to use the replacement. An invalid code +causes a panic log; in this case, if the log messages is the same as the user +message, we must also adjust the value of the log message to show the code that +is actually going to be used (the original one). + +This function is global because it is called from receive.c as well as within +this module. + +Note that the code length returned includes the terminating whitespace +character, which is always included in the regex match. + +Arguments: + code SMTP code, may involve extended status codes + codelen length of smtp code; if > 4 there's an ESC + msg message text + log_msg optional log message, to be adjusted with the new SMTP code + check_valid if true, verify the response code + +Returns: nothing +*/ + +void +smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg, + BOOL check_valid) +{ +int n; +int ovector[3]; + +if (!msg || !*msg) return; + +if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0, + PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return; + +if (check_valid && (*msg)[0] != (*code)[0]) + { + log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with " + "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg); + if (log_msg != NULL && *log_msg == *msg) + *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]); + } +else + { + *code = *msg; + *codelen = ovector[1]; /* Includes final space */ + } +*msg += ovector[1]; /* Chop the code off the message */ +return; +} + + + + +/************************************************* +* Handle an ACL failure * +*************************************************/ + +/* This function is called when acl_check() fails. As well as calls from within +this module, it is called from receive.c for an ACL after DATA. It sorts out +logging the incident, and sends the error response. A message containing +newlines is turned into a multiline SMTP response, but for logging, only the +first line is used. + +There's a table of default permanent failure response codes to use in +globals.c, along with the table of names. VFRY is special. Despite RFC1123 it +defaults disabled in Exim. However, discussion in connection with RFC 821bis +(aka RFC 2821) has concluded that the response should be 252 in the disabled +state, because there are broken clients that try VRFY before RCPT. A 5xx +response should be given only when the address is positively known to be +undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides +no explicit code, but if there is one we let it know best. +Also, for ETRN, 458 is given on refusal, and for AUTH, 503. + +From Exim 4.63, it is possible to override the response code details by +providing a suitable response code string at the start of the message provided +in user_msg. The code's first digit is checked for validity. + +Arguments: + where where the ACL was called from + rc the failure code + user_msg a message that can be included in an SMTP response + log_msg a message for logging + +Returns: 0 in most cases + 2 if the failure code was FAIL_DROP, in which case the + SMTP connection should be dropped (this value fits with the + "done" variable in smtp_setup_msg() below) +*/ + +int +smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg) +{ +BOOL drop = rc == FAIL_DROP; +int codelen = 3; +uschar *smtp_code; +uschar *lognl; +uschar *sender_info = US""; +uschar *what = +#ifdef WITH_CONTENT_SCAN + where == ACL_WHERE_MIME ? US"during MIME ACL checks" : +#endif + where == ACL_WHERE_PREDATA ? US"DATA" : + where == ACL_WHERE_DATA ? US"after DATA" : +#ifndef DISABLE_PRDR + where == ACL_WHERE_PRDR ? US"after DATA PRDR" : +#endif + smtp_cmd_data ? + string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) : + string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]); + +if (drop) rc = FAIL; + +/* Set the default SMTP code, and allow a user message to change it. */ + +smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451"; +smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg, + where != ACL_WHERE_VRFY); + +/* We used to have sender_address here; however, there was a bug that was not +updating sender_address after a rewrite during a verify. When this bug was +fixed, sender_address at this point became the rewritten address. I'm not sure +this is what should be logged, so I've changed to logging the unrewritten +address to retain backward compatibility. */ + +#ifndef WITH_CONTENT_SCAN +if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA) +#else +if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME) +#endif + { + sender_info = string_sprintf("F=<%s>%s%s%s%s ", + sender_address_unrewritten ? sender_address_unrewritten : sender_address, + sender_host_authenticated ? US" A=" : US"", + sender_host_authenticated ? sender_host_authenticated : US"", + sender_host_authenticated && authenticated_id ? US":" : US"", + sender_host_authenticated && authenticated_id ? authenticated_id : US"" + ); + } + +/* If there's been a sender verification failure with a specific message, and +we have not sent a response about it yet, do so now, as a preliminary line for +failures, but not defers. However, always log it for defer, and log it for fail +unless the sender_verify_fail log selector has been turned off. */ + +if (sender_verified_failed && + !testflag(sender_verified_failed, af_sverify_told)) + { + BOOL save_rcpt_in_progress = fl.rcpt_in_progress; + fl.rcpt_in_progress = FALSE; /* So as not to treat these as the error */ + + setflag(sender_verified_failed, af_sverify_told); + + if (rc != FAIL || LOGGING(sender_verify_fail)) + log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s", + host_and_ident(TRUE), + ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail", + sender_verified_failed->address, + (sender_verified_failed->message == NULL)? US"" : + string_sprintf(": %s", sender_verified_failed->message)); + + if (rc == FAIL && sender_verified_failed->user_message) + smtp_respond(smtp_code, codelen, FALSE, string_sprintf( + testflag(sender_verified_failed, af_verify_pmfail)? + "Postmaster verification failed while checking <%s>\n%s\n" + "Several RFCs state that you are required to have a postmaster\n" + "mailbox for each mail domain. This host does not accept mail\n" + "from domains whose servers reject the postmaster address." + : + testflag(sender_verified_failed, af_verify_nsfail)? + "Callback setup failed while verifying <%s>\n%s\n" + "The initial connection, or a HELO or MAIL FROM:<> command was\n" + "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n" + "RFC requirements, and stops you from receiving standard bounce\n" + "messages. This host does not accept mail from domains whose servers\n" + "refuse bounces." + : + "Verification failed for <%s>\n%s", + sender_verified_failed->address, + sender_verified_failed->user_message)); + + fl.rcpt_in_progress = save_rcpt_in_progress; + } + +/* Sort out text for logging */ + +log_msg = log_msg ? string_sprintf(": %s", log_msg) : US""; +if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0; + +/* Send permanent failure response to the command, but the code used isn't +always a 5xx one - see comments at the start of this function. If the original +rc was FAIL_DROP we drop the connection and yield 2. */ + +if (rc == FAIL) + smtp_respond(smtp_code, codelen, TRUE, + user_msg ? user_msg : US"Administrative prohibition"); + +/* Send temporary failure response to the command. Don't give any details, +unless acl_temp_details is set. This is TRUE for a callout defer, a "defer" +verb, and for a header verify when smtp_return_error_details is set. + +This conditional logic is all somewhat of a mess because of the odd +interactions between temp_details and return_error_details. One day it should +be re-implemented in a tidier fashion. */ + +else + if (f.acl_temp_details && user_msg) + { + if ( smtp_return_error_details + && sender_verified_failed + && sender_verified_failed->message + ) + smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message); + + smtp_respond(smtp_code, codelen, TRUE, user_msg); + } + else + smtp_respond(smtp_code, codelen, TRUE, + US"Temporary local problem - please try later"); + +/* Log the incident to the logs that are specified by log_reject_target +(default main, reject). This can be empty to suppress logging of rejections. If +the connection is not forcibly to be dropped, return 0. Otherwise, log why it +is closing if required and return 2. */ + +if (log_reject_target != 0) + { +#ifdef SUPPORT_TLS + gstring * g = s_tlslog(NULL); + uschar * tls = string_from_gstring(g); + if (!tls) tls = US""; +#else + uschar * tls = US""; +#endif + log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0, + log_reject_target, "%s%s%s %s%srejected %s%s", + LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"", + host_and_ident(TRUE), + tls, + sender_info, + rc == FAIL ? US"" : US"temporarily ", + what, log_msg); + } + +if (!drop) return 0; + +log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL", + smtp_get_connection_info()); + +/* Run the not-quit ACL, but without any custom messages. This should not be a +problem, because we get here only if some other ACL has issued "drop", and +in that case, *its* custom messages will have been used above. */ + +smtp_notquit_exit(US"acl-drop", NULL, NULL); +return 2; +} + + + + +/************************************************* +* Handle SMTP exit when QUIT is not given * +*************************************************/ + +/* This function provides a logging/statistics hook for when an SMTP connection +is dropped on the floor or the other end goes away. It's a global function +because it's called from receive.c as well as this module. As well as running +the NOTQUIT ACL, if there is one, this function also outputs a final SMTP +response, either with a custom message from the ACL, or using a default. There +is one case, however, when no message is output - after "drop". In that case, +the ACL that obeyed "drop" has already supplied the custom message, and NULL is +passed to this function. + +In case things go wrong while processing this function, causing an error that +may re-enter this function, there is a recursion check. + +Arguments: + reason What $smtp_notquit_reason will be set to in the ACL; + if NULL, the ACL is not run + code The error code to return as part of the response + defaultrespond The default message if there's no user_msg + +Returns: Nothing +*/ + +void +smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...) +{ +int rc; +uschar *user_msg = NULL; +uschar *log_msg = NULL; + +/* Check for recursive call */ + +if (fl.smtp_exit_function_called) + { + log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)", + reason); + return; + } +fl.smtp_exit_function_called = TRUE; + +/* Call the not-QUIT ACL, if there is one, unless no reason is given. */ + +if (acl_smtp_notquit && reason) + { + smtp_notquit_reason = reason; + if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg, + &log_msg)) == ERROR) + log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s", + log_msg); + } + +/* If the connection was dropped, we certainly are no longer talking TLS */ +tls_in.active.sock = -1; + +/* Write an SMTP response if we are expected to give one. As the default +responses are all internal, they should be reasonable size. */ + +if (code && defaultrespond) + { + if (user_msg) + smtp_respond(code, 3, TRUE, user_msg); + else + { + gstring * g; + va_list ap; + + va_start(ap, defaultrespond); + g = string_vformat(NULL, TRUE, CS defaultrespond, ap); + va_end(ap); + smtp_printf("%s %s\r\n", FALSE, code, string_from_gstring(g)); + } + mac_smtp_fflush(); + } +} + + + + +/************************************************* +* Verify HELO argument * +*************************************************/ + +/* This function is called if helo_verify_hosts or helo_try_verify_hosts is +matched. It is also called from ACL processing if verify = helo is used and +verification was not previously tried (i.e. helo_try_verify_hosts was not +matched). The result of its processing is to set helo_verified and +helo_verify_failed. These variables should both be FALSE for this function to +be called. + +Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow +for IPv6 ::ffff: literals. + +Argument: none +Returns: TRUE if testing was completed; + FALSE on a temporary failure +*/ + +BOOL +smtp_verify_helo(void) +{ +BOOL yield = TRUE; + +HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n", + sender_helo_name); + +if (sender_helo_name == NULL) + { + HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n"); + } + +/* Deal with the case of -bs without an IP address */ + +else if (sender_host_address == NULL) + { + HDEBUG(D_receive) debug_printf("no client IP address: assume success\n"); + f.helo_verified = TRUE; + } + +/* Deal with the more common case when there is a sending IP address */ + +else if (sender_helo_name[0] == '[') + { + f.helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address, + Ustrlen(sender_host_address)) == 0; + +#if HAVE_IPV6 + if (!f.helo_verified) + { + if (strncmpic(sender_host_address, US"::ffff:", 7) == 0) + f.helo_verified = Ustrncmp(sender_helo_name + 1, + sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0; + } +#endif + + HDEBUG(D_receive) + { if (f.helo_verified) debug_printf("matched host address\n"); } + } + +/* Do a reverse lookup if one hasn't already given a positive or negative +response. If that fails, or the name doesn't match, try checking with a forward +lookup. */ + +else + { + if (sender_host_name == NULL && !host_lookup_failed) + yield = host_name_lookup() != DEFER; + + /* If a host name is known, check it and all its aliases. */ + + if (sender_host_name) + if ((f.helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0)) + { + sender_helo_dnssec = sender_host_dnssec; + HDEBUG(D_receive) debug_printf("matched host name\n"); + } + else + { + uschar **aliases = sender_host_aliases; + while (*aliases) + if ((f.helo_verified = strcmpic(*aliases++, sender_helo_name) == 0)) + { + sender_helo_dnssec = sender_host_dnssec; + break; + } + + HDEBUG(D_receive) if (f.helo_verified) + debug_printf("matched alias %s\n", *(--aliases)); + } + + /* Final attempt: try a forward lookup of the helo name */ + + if (!f.helo_verified) + { + int rc; + host_item h; + dnssec_domains d; + host_item *hh; + + h.name = sender_helo_name; + h.address = NULL; + h.mx = MX_NONE; + h.next = NULL; + d.request = US"*"; + d.require = US""; + + HDEBUG(D_receive) debug_printf("getting IP address for %s\n", + sender_helo_name); + rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA, + NULL, NULL, NULL, &d, NULL, NULL); + if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL) + for (hh = &h; hh; hh = hh->next) + if (Ustrcmp(hh->address, sender_host_address) == 0) + { + f.helo_verified = TRUE; + if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE; + HDEBUG(D_receive) + { + debug_printf("IP address for %s matches calling address\n" + "Forward DNS security status: %sverified\n", + sender_helo_name, sender_helo_dnssec ? "" : "un"); + } + break; + } + } + } + +if (!f.helo_verified) f.helo_verify_failed = TRUE; /* We've tried ... */ +return yield; +} + + + + +/************************************************* +* Send user response message * +*************************************************/ + +/* This function is passed a default response code and a user message. It calls +smtp_message_code() to check and possibly modify the response code, and then +calls smtp_respond() to transmit the response. I put this into a function +just to avoid a lot of repetition. + +Arguments: + code the response code + user_msg the user message + +Returns: nothing +*/ + +static void +smtp_user_msg(uschar *code, uschar *user_msg) +{ +int len = 3; +smtp_message_code(&code, &len, &user_msg, NULL, TRUE); +smtp_respond(code, len, TRUE, user_msg); +} + + + +static int +smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss) +{ +const uschar *set_id = NULL; +int rc, i; + +/* Run the checking code, passing the remainder of the command line as +data. Initials the $auth<n> variables as empty. Initialize $0 empty and set +it as the only set numerical variable. The authenticator may set $auth<n> +and also set other numeric variables. The $auth<n> variables are preferred +nowadays; the numerical variables remain for backwards compatibility. + +Afterwards, have a go at expanding the set_id string, even if +authentication failed - for bad passwords it can be useful to log the +userid. On success, require set_id to expand and exist, and put it in +authenticated_id. Save this in permanent store, as the working store gets +reset at HELO, RSET, etc. */ + +for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; +expand_nmax = 0; +expand_nlength[0] = 0; /* $0 contains nothing */ + +rc = (au->info->servercode)(au, smtp_cmd_data); +if (au->set_id) set_id = expand_string(au->set_id); +expand_nmax = -1; /* Reset numeric variables */ +for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */ + +/* The value of authenticated_id is stored in the spool file and printed in +log lines. It must not contain binary zeros or newline characters. In +normal use, it never will, but when playing around or testing, this error +can (did) happen. To guard against this, ensure that the id contains only +printing characters. */ + +if (set_id) set_id = string_printing(set_id); + +/* For the non-OK cases, set up additional logging data if set_id +is not empty. */ + +if (rc != OK) + set_id = set_id && *set_id + ? string_sprintf(" (set_id=%s)", set_id) : US""; + +/* Switch on the result */ + +switch(rc) + { + case OK: + if (!au->set_id || set_id) /* Complete success */ + { + if (set_id) authenticated_id = string_copy_malloc(set_id); + sender_host_authenticated = au->name; + sender_host_auth_pubname = au->public_name; + authentication_failed = FALSE; + authenticated_fail_id = NULL; /* Impossible to already be set? */ + + received_protocol = + (sender_host_address ? protocols : protocols_local) + [pextend + pauthed + (tls_in.active.sock >= 0 ? pcrpted:0)]; + *s = *ss = US"235 Authentication succeeded"; + authenticated_by = au; + break; + } + + /* Authentication succeeded, but we failed to expand the set_id string. + Treat this as a temporary error. */ + + auth_defer_msg = expand_string_message; + /* Fall through */ + + case DEFER: + if (set_id) authenticated_fail_id = string_copy_malloc(set_id); + *s = string_sprintf("435 Unable to authenticate at present%s", + auth_defer_user_msg); + *ss = string_sprintf("435 Unable to authenticate at present%s: %s", + set_id, auth_defer_msg); + break; + + case BAD64: + *s = *ss = US"501 Invalid base64 data"; + break; + + case CANCELLED: + *s = *ss = US"501 Authentication cancelled"; + break; + + case UNEXPECTED: + *s = *ss = US"553 Initial data not expected"; + break; + + case FAIL: + if (set_id) authenticated_fail_id = string_copy_malloc(set_id); + *s = US"535 Incorrect authentication data"; + *ss = string_sprintf("535 Incorrect authentication data%s", set_id); + break; + + default: + if (set_id) authenticated_fail_id = string_copy_malloc(set_id); + *s = US"435 Internal error"; + *ss = string_sprintf("435 Internal error%s: return %d from authentication " + "check", set_id, rc); + break; + } + +return rc; +} + + + + + +static int +qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag) +{ +int rd; +if (f.allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0) + { + DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", + *recipient); + rd = Ustrlen(recipient) + 1; + *recipient = rewrite_address_qualify(*recipient, TRUE); + return rd; + } +smtp_printf("501 %s: recipient address must contain a domain\r\n", FALSE, + smtp_cmd_data); +log_write(L_smtp_syntax_error, + LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s", + tag, *recipient, host_and_ident(TRUE), host_lookup_msg); +return 0; +} + + + + +static void +smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp) +{ +HAD(SCH_QUIT); +incomplete_transaction_log(US"QUIT"); +if (acl_smtp_quit) + { + int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp); + if (rc == ERROR) + log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s", + *log_msgp); + } +if (*user_msgp) + smtp_respond(US"221", 3, TRUE, *user_msgp); +else + smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname); + +#ifdef SUPPORT_TLS +tls_close(NULL, TLS_SHUTDOWN_NOWAIT); +#endif + +log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT", + smtp_get_connection_info()); +} + + +static void +smtp_rset_handler(void) +{ +HAD(SCH_RSET); +incomplete_transaction_log(US"RSET"); +smtp_printf("250 Reset OK\r\n", FALSE); +cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE; +} + + + +/************************************************* +* Initialize for SMTP incoming message * +*************************************************/ + +/* This function conducts the initial dialogue at the start of an incoming SMTP +message, and builds a list of recipients. However, if the incoming message +is part of a batch (-bS option) a separate function is called since it would +be messy having tests splattered about all over this function. This function +therefore handles the case where interaction is occurring. The input and output +files are set up in smtp_in and smtp_out. + +The global recipients_list is set to point to a vector of recipient_item +blocks, whose number is given by recipients_count. This is extended by the +receive_add_recipient() function. The global variable sender_address is set to +the sender's address. The yield is +1 if a message has been successfully +started, 0 if a QUIT command was encountered or the connection was refused from +the particular host, or -1 if the connection was lost. + +Argument: none + +Returns: > 0 message successfully started (reached DATA) + = 0 QUIT read or end of file reached or call refused + < 0 lost connection +*/ + +int +smtp_setup_msg(void) +{ +int done = 0; +BOOL toomany = FALSE; +BOOL discarded = FALSE; +BOOL last_was_rej_mail = FALSE; +BOOL last_was_rcpt = FALSE; +void *reset_point = store_get(0); + +DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n"); + +/* Reset for start of new message. We allow one RSET not to be counted as a +nonmail command, for those MTAs that insist on sending it between every +message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of +TLS between messages (an Exim client may do this if it has messages queued up +for the host). Note: we do NOT reset AUTH at this point. */ + +smtp_reset(reset_point); +message_ended = END_NOTSTARTED; + +chunking_state = f.chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED; + +cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE; +cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE; +cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE; +#ifdef SUPPORT_TLS +cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE; +#endif + +/* Set the local signal handler for SIGTERM - it tries to end off tidily */ + +had_command_sigterm = 0; +os_non_restarting_signal(SIGTERM, command_sigterm_handler); + +/* Batched SMTP is handled in a different function. */ + +if (smtp_batched_input) return smtp_setup_batch_msg(); + +/* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE +value. The values are 2 larger than the required yield of the function. */ + +while (done <= 0) + { + const uschar **argv; + uschar *etrn_command; + uschar *etrn_serialize_key; + uschar *errmess; + uschar *log_msg, *smtp_code; + uschar *user_msg = NULL; + uschar *recipient = NULL; + uschar *hello = NULL; + uschar *s, *ss; + BOOL was_rej_mail = FALSE; + BOOL was_rcpt = FALSE; + void (*oldsignal)(int); + pid_t pid; + int start, end, sender_domain, recipient_domain; + int rc; + int c; + auth_instance *au; + uschar *orcpt = NULL; + int dsn_flags; + gstring * g; + +#ifdef AUTH_TLS + /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */ + if ( tls_in.active.sock >= 0 + && tls_in.peercert + && tls_in.certificate_verified + && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd + ) + { + cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE; + + for (au = auths; au; au = au->next) + if (strcmpic(US"tls", au->driver_name) == 0) + { + if ( acl_smtp_auth + && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, + &user_msg, &log_msg)) != OK + ) + done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg); + else + { + smtp_cmd_data = NULL; + + if (smtp_in_auth(au, &s, &ss) == OK) + { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); } + else + { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); } + } + break; + } + } +#endif + +#ifdef TCP_QUICKACK + if (smtp_in) /* Avoid pure-ACKs while in cmd pingpong phase */ + (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK, + US &off, sizeof(off)); +#endif + + switch(smtp_read_command( +#ifdef EXPERIMENTAL_PIPE_CONNECT + !fl.pipe_connect_acceptable, +#else + TRUE, +#endif + GETC_BUFFER_UNLIMITED)) + { + /* The AUTH command is not permitted to occur inside a transaction, and may + occur successfully only once per connection. Actually, that isn't quite + true. When TLS is started, all previous information about a connection must + be discarded, so a new AUTH is permitted at that time. + + AUTH may only be used when it has been advertised. However, it seems that + there are clients that send AUTH when it hasn't been advertised, some of + them even doing this after HELO. And there are MTAs that accept this. Sigh. + So there's a get-out that allows this to happen. + + AUTH is initially labelled as a "nonmail command" so that one occurrence + doesn't get counted. We change the label here so that multiple failing + AUTHS will eventually hit the nonmail threshold. */ + + case AUTH_CMD: + HAD(SCH_AUTH); + authentication_failed = TRUE; + cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE; + + if (!fl.auth_advertised && !f.allow_auth_unadvertised) + { + done = synprot_error(L_smtp_protocol_error, 503, NULL, + US"AUTH command used when not advertised"); + break; + } + if (sender_host_authenticated) + { + done = synprot_error(L_smtp_protocol_error, 503, NULL, + US"already authenticated"); + break; + } + if (sender_address) + { + done = synprot_error(L_smtp_protocol_error, 503, NULL, + US"not permitted in mail transaction"); + break; + } + + /* Check the ACL */ + + if ( acl_smtp_auth + && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth, + &user_msg, &log_msg)) != OK + ) + { + done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg); + break; + } + + /* Find the name of the requested authentication mechanism. */ + + s = smtp_cmd_data; + while ((c = *smtp_cmd_data) != 0 && !isspace(c)) + { + if (!isalnum(c) && c != '-' && c != '_') + { + done = synprot_error(L_smtp_syntax_error, 501, NULL, + US"invalid character in authentication mechanism name"); + goto COMMAND_LOOP; + } + smtp_cmd_data++; + } + + /* If not at the end of the line, we must be at white space. Terminate the + name and move the pointer on to any data that may be present. */ + + if (*smtp_cmd_data != 0) + { + *smtp_cmd_data++ = 0; + while (isspace(*smtp_cmd_data)) smtp_cmd_data++; + } + + /* Search for an authentication mechanism which is configured for use + as a server and which has been advertised (unless, sigh, allow_auth_ + unadvertised is set). */ + + for (au = auths; au; au = au->next) + if (strcmpic(s, au->public_name) == 0 && au->server && + (au->advertised || f.allow_auth_unadvertised)) + break; + + if (au) + { + c = smtp_in_auth(au, &s, &ss); + + smtp_printf("%s\r\n", FALSE, s); + if (c != OK) + log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s", + au->name, host_and_ident(FALSE), ss); + } + else + done = synprot_error(L_smtp_protocol_error, 504, NULL, + string_sprintf("%s authentication mechanism not supported", s)); + + break; /* AUTH_CMD */ + + /* The HELO/EHLO commands are permitted to appear in the middle of a + session as well as at the beginning. They have the effect of a reset in + addition to their other functions. Their absence at the start cannot be + taken to be an error. + + RFC 2821 says: + + If the EHLO command is not acceptable to the SMTP server, 501, 500, + or 502 failure replies MUST be returned as appropriate. The SMTP + server MUST stay in the same state after transmitting these replies + that it was in before the EHLO was received. + + Therefore, we do not do the reset until after checking the command for + acceptability. This change was made for Exim release 4.11. Previously + it did the reset first. */ + + case HELO_CMD: + HAD(SCH_HELO); + hello = US"HELO"; + fl.esmtp = FALSE; + goto HELO_EHLO; + + case EHLO_CMD: + HAD(SCH_EHLO); + hello = US"EHLO"; + fl.esmtp = TRUE; + + HELO_EHLO: /* Common code for HELO and EHLO */ + cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE; + cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE; + + /* Reject the HELO if its argument was invalid or non-existent. A + successful check causes the argument to be saved in malloc store. */ + + if (!check_helo(smtp_cmd_data)) + { + smtp_printf("501 Syntactically invalid %s argument(s)\r\n", FALSE, hello); + + log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically " + "invalid argument(s): %s", hello, host_and_ident(FALSE), + *smtp_cmd_argument == 0 ? US"(no argument given)" : + string_printing(smtp_cmd_argument)); + + if (++synprot_error_count > smtp_max_synprot_errors) + { + log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " + "syntax or protocol errors (last command was \"%s\")", + host_and_ident(FALSE), string_printing(smtp_cmd_buffer)); + done = 1; + } + + break; + } + + /* If sender_host_unknown is true, we have got here via the -bs interface, + not called from inetd. Otherwise, we are running an IP connection and the + host address will be set. If the helo name is the primary name of this + host and we haven't done a reverse lookup, force one now. If helo_required + is set, ensure that the HELO name matches the actual host. If helo_verify + is set, do the same check, but softly. */ + + if (!f.sender_host_unknown) + { + BOOL old_helo_verified = f.helo_verified; + uschar *p = smtp_cmd_data; + + while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; } + *p = 0; + + /* Force a reverse lookup if HELO quoted something in helo_lookup_domains + because otherwise the log can be confusing. */ + + if ( !sender_host_name + && match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0, + &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK) + (void)host_name_lookup(); + + /* Rebuild the fullhost info to include the HELO name (and the real name + if it was looked up.) */ + + host_build_sender_fullhost(); /* Rebuild */ + set_process_info("handling%s incoming connection from %s", + tls_in.active.sock >= 0 ? " TLS" : "", host_and_ident(FALSE)); + + /* Verify if configured. This doesn't give much security, but it does + make some people happy to be able to do it. If helo_required is set, + (host matches helo_verify_hosts) failure forces rejection. If helo_verify + is set (host matches helo_try_verify_hosts), it does not. This is perhaps + now obsolescent, since the verification can now be requested selectively + at ACL time. */ + + f.helo_verified = f.helo_verify_failed = sender_helo_dnssec = FALSE; + if (fl.helo_required || fl.helo_verify) + { + BOOL tempfail = !smtp_verify_helo(); + if (!f.helo_verified) + { + if (fl.helo_required) + { + smtp_printf("%d %s argument does not match calling host\r\n", FALSE, + tempfail? 451 : 550, hello); + log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s", + tempfail? "temporarily " : "", + hello, sender_helo_name, host_and_ident(FALSE)); + f.helo_verified = old_helo_verified; + break; /* End of HELO/EHLO processing */ + } + HDEBUG(D_all) debug_printf("%s verification failed but host is in " + "helo_try_verify_hosts\n", hello); + } + } + } + +#ifdef SUPPORT_SPF + /* set up SPF context */ + spf_init(sender_helo_name, sender_host_address); +#endif + + /* Apply an ACL check if one is defined; afterwards, recheck + synchronization in case the client started sending in a delay. */ + + if (acl_smtp_helo) + if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo, + &user_msg, &log_msg)) != OK) + { + done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg); + if (sender_helo_name) + { + store_free(sender_helo_name); + sender_helo_name = NULL; + } + host_build_sender_fullhost(); /* Rebuild */ + break; + } +#ifdef EXPERIMENTAL_PIPE_CONNECT + else if (!fl.pipe_connect_acceptable && !check_sync()) +#else + else if (!check_sync()) +#endif + goto SYNC_FAILURE; + + /* Generate an OK reply. The default string includes the ident if present, + and also the IP address if present. Reflecting back the ident is intended + as a deterrent to mail forgers. For maximum efficiency, and also because + some broken systems expect each response to be in a single packet, arrange + that the entire reply is sent in one write(). */ + + fl.auth_advertised = FALSE; + f.smtp_in_pipelining_advertised = FALSE; +#ifdef SUPPORT_TLS + fl.tls_advertised = FALSE; +# ifdef EXPERIMENTAL_REQUIRETLS + fl.requiretls_advertised = FALSE; +# endif +#endif + fl.dsn_advertised = FALSE; +#ifdef SUPPORT_I18N + fl.smtputf8_advertised = FALSE; +#endif + + smtp_code = US"250 "; /* Default response code plus space*/ + if (!user_msg) + { + g = string_fmt_append(NULL, "%.3s %s Hello %s%s%s", + smtp_code, + smtp_active_hostname, + sender_ident ? sender_ident : US"", + sender_ident ? US" at " : US"", + sender_host_name ? sender_host_name : sender_helo_name); + + if (sender_host_address) + g = string_fmt_append(g, " [%s]", sender_host_address); + } + + /* A user-supplied EHLO greeting may not contain more than one line. Note + that the code returned by smtp_message_code() includes the terminating + whitespace character. */ + + else + { + char *ss; + int codelen = 4; + smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE); + s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg); + if ((ss = strpbrk(CS s, "\r\n")) != NULL) + { + log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain " + "newlines: message truncated: %s", string_printing(s)); + *ss = 0; + } + g = string_cat(NULL, s); + } + + g = string_catn(g, US"\r\n", 2); + + /* If we received EHLO, we must create a multiline response which includes + the functions supported. */ + + if (fl.esmtp) + { + g->s[3] = '-'; + + /* I'm not entirely happy with this, as an MTA is supposed to check + that it has enough room to accept a message of maximum size before + it sends this. However, there seems little point in not sending it. + The actual size check happens later at MAIL FROM time. By postponing it + till then, VRFY and EXPN can be used after EHLO when space is short. */ + + if (thismessage_size_limit > 0) + g = string_fmt_append(g, "%.3s-SIZE %d\r\n", smtp_code, + thismessage_size_limit); + else + { + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US"-SIZE\r\n", 7); + } + + /* Exim does not do protocol conversion or data conversion. It is 8-bit + clean; if it has an 8-bit character in its hand, it just sends it. It + cannot therefore specify 8BITMIME and remain consistent with the RFCs. + However, some users want this option simply in order to stop MUAs + mangling messages that contain top-bit-set characters. It is therefore + provided as an option. */ + + if (accept_8bitmime) + { + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US"-8BITMIME\r\n", 11); + } + + /* Advertise DSN support if configured to do so. */ + if (verify_check_host(&dsn_advertise_hosts) != FAIL) + { + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US"-DSN\r\n", 6); + fl.dsn_advertised = TRUE; + } + + /* Advertise ETRN/VRFY/EXPN if there's are ACL checking whether a host is + permitted to issue them; a check is made when any host actually tries. */ + + if (acl_smtp_etrn) + { + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US"-ETRN\r\n", 7); + } + if (acl_smtp_vrfy) + { + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US"-VRFY\r\n", 7); + } + if (acl_smtp_expn) + { + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US"-EXPN\r\n", 7); + } + + /* Exim is quite happy with pipelining, so let the other end know that + it is safe to use it, unless advertising is disabled. */ + + if ( f.pipelining_enable + && verify_check_host(&pipelining_advertise_hosts) == OK) + { + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US"-PIPELINING\r\n", 13); + sync_cmd_limit = NON_SYNC_CMD_PIPELINING; + f.smtp_in_pipelining_advertised = TRUE; + +#ifdef EXPERIMENTAL_PIPE_CONNECT + if (fl.pipe_connect_acceptable) + { + f.smtp_in_early_pipe_advertised = TRUE; + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US"-" EARLY_PIPE_FEATURE_NAME "\r\n", EARLY_PIPE_FEATURE_LEN+3); + } +#endif + } + + + /* If any server authentication mechanisms are configured, advertise + them if the current host is in auth_advertise_hosts. The problem with + advertising always is that some clients then require users to + authenticate (and aren't configurable otherwise) even though it may not + be necessary (e.g. if the host is in host_accept_relay). + + RFC 2222 states that SASL mechanism names contain only upper case + letters, so output the names in upper case, though we actually recognize + them in either case in the AUTH command. */ + + if ( auths +#ifdef AUTH_TLS + && !sender_host_authenticated +#endif + && verify_check_host(&auth_advertise_hosts) == OK + ) + { + auth_instance *au; + BOOL first = TRUE; + for (au = auths; au; au = au->next) + { + au->advertised = FALSE; + if (au->server) + { + DEBUG(D_auth+D_expand) debug_printf_indent( + "Evaluating advertise_condition for %s athenticator\n", + au->public_name); + if ( !au->advertise_condition + || expand_check_condition(au->advertise_condition, au->name, + US"authenticator") + ) + { + int saveptr; + if (first) + { + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US"-AUTH", 5); + first = FALSE; + fl.auth_advertised = TRUE; + } + saveptr = g->ptr; + g = string_catn(g, US" ", 1); + g = string_cat (g, au->public_name); + while (++saveptr < g->ptr) g->s[saveptr] = toupper(g->s[saveptr]); + au->advertised = TRUE; + } + } + } + + if (!first) g = string_catn(g, US"\r\n", 2); + } + + /* RFC 3030 CHUNKING */ + + if (verify_check_host(&chunking_advertise_hosts) != FAIL) + { + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US"-CHUNKING\r\n", 11); + f.chunking_offered = TRUE; + chunking_state = CHUNKING_OFFERED; + } + + /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer) + if it has been included in the binary, and the host matches + tls_advertise_hosts. We must *not* advertise if we are already in a + secure connection. */ + +#ifdef SUPPORT_TLS + if (tls_in.active.sock < 0 && + verify_check_host(&tls_advertise_hosts) != FAIL) + { + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US"-STARTTLS\r\n", 11); + fl.tls_advertised = TRUE; + } + +# ifdef EXPERIMENTAL_REQUIRETLS + /* Advertise REQUIRETLS only once we are in a secure connection */ + if ( tls_in.active.sock >= 0 + && verify_check_host(&tls_advertise_requiretls) != FAIL) + { + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US"-REQUIRETLS\r\n", 13); + fl.requiretls_advertised = TRUE; + } +# endif +#endif + +#ifndef DISABLE_PRDR + /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */ + if (prdr_enable) + { + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US"-PRDR\r\n", 7); + } +#endif + +#ifdef SUPPORT_I18N + if ( accept_8bitmime + && verify_check_host(&smtputf8_advertise_hosts) != FAIL) + { + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US"-SMTPUTF8\r\n", 11); + fl.smtputf8_advertised = TRUE; + } +#endif + + /* Finish off the multiline reply with one that is always available. */ + + g = string_catn(g, smtp_code, 3); + g = string_catn(g, US" HELP\r\n", 7); + } + + /* Terminate the string (for debug), write it, and note that HELO/EHLO + has been seen. */ + +#ifdef SUPPORT_TLS + if (tls_in.active.sock >= 0) + (void)tls_write(NULL, g->s, g->ptr, +# ifdef EXPERIMENTAL_PIPE_CONNECT + fl.pipe_connect_acceptable && pipeline_connect_sends()); +# else + FALSE); +# endif + else +#endif + + { + int i = fwrite(g->s, 1, g->ptr, smtp_out); i = i; /* compiler quietening */ + } + DEBUG(D_receive) + { + uschar *cr; + + (void) string_from_gstring(g); + while ((cr = Ustrchr(g->s, '\r')) != NULL) /* lose CRs */ + memmove(cr, cr + 1, (g->ptr--) - (cr - g->s)); + debug_printf("SMTP>> %s", g->s); + } + fl.helo_seen = TRUE; + + /* Reset the protocol and the state, abandoning any previous message. */ + received_protocol = + (sender_host_address ? protocols : protocols_local) + [ (fl.esmtp + ? pextend + (sender_host_authenticated ? pauthed : 0) + : pnormal) + + (tls_in.active.sock >= 0 ? pcrpted : 0) + ]; + cancel_cutthrough_connection(TRUE, US"sent EHLO response"); + smtp_reset(reset_point); + toomany = FALSE; + break; /* HELO/EHLO */ + + + /* The MAIL command requires an address as an operand. All we do + here is to parse it for syntactic correctness. The form "<>" is + a special case which converts into an empty string. The start/end + pointers in the original are not used further for this address, as + it is the canonical extracted address which is all that is kept. */ + + case MAIL_CMD: + HAD(SCH_MAIL); + smtp_mailcmd_count++; /* Count for limit and ratelimit */ + was_rej_mail = TRUE; /* Reset if accepted */ + env_mail_type_t * mail_args; /* Sanity check & validate args */ + + if (fl.helo_required && !fl.helo_seen) + { + smtp_printf("503 HELO or EHLO required\r\n", FALSE); + log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no " + "HELO/EHLO given", host_and_ident(FALSE)); + break; + } + + if (sender_address) + { + done = synprot_error(L_smtp_protocol_error, 503, NULL, + US"sender already given"); + break; + } + + if (!*smtp_cmd_data) + { + done = synprot_error(L_smtp_protocol_error, 501, NULL, + US"MAIL must have an address operand"); + break; + } + + /* Check to see if the limit for messages per connection would be + exceeded by accepting further messages. */ + + if (smtp_accept_max_per_connection > 0 && + smtp_mailcmd_count > smtp_accept_max_per_connection) + { + smtp_printf("421 too many messages in this connection\r\n", FALSE); + log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many " + "messages in one connection", host_and_ident(TRUE)); + break; + } + + /* Reset for start of message - even if this is going to fail, we + obviously need to throw away any previous data. */ + + cancel_cutthrough_connection(TRUE, US"MAIL received"); + smtp_reset(reset_point); + toomany = FALSE; + sender_data = recipient_data = NULL; + + /* Loop, checking for ESMTP additions to the MAIL FROM command. */ + + if (fl.esmtp) for(;;) + { + uschar *name, *value, *end; + unsigned long int size; + BOOL arg_error = FALSE; + + if (!extract_option(&name, &value)) break; + + for (mail_args = env_mail_type_list; + mail_args->value != ENV_MAIL_OPT_NULL; + mail_args++ + ) + if (strcmpic(name, mail_args->name) == 0) + break; + if (mail_args->need_value && strcmpic(value, US"") == 0) + break; + + switch(mail_args->value) + { + /* Handle SIZE= by reading the value. We don't do the check till later, + in order to be able to log the sender address on failure. */ + case ENV_MAIL_OPT_SIZE: + if (((size = Ustrtoul(value, &end, 10)), *end == 0)) + { + if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX) + size = INT_MAX; + message_size = (int)size; + } + else + arg_error = TRUE; + break; + + /* If this session was initiated with EHLO and accept_8bitmime is set, + Exim will have indicated that it supports the BODY=8BITMIME option. In + fact, it does not support this according to the RFCs, in that it does not + take any special action for forwarding messages containing 8-bit + characters. That is why accept_8bitmime is not the default setting, but + some sites want the action that is provided. We recognize both "8BITMIME" + and "7BIT" as body types, but take no action. */ + case ENV_MAIL_OPT_BODY: + if (accept_8bitmime) { + if (strcmpic(value, US"8BITMIME") == 0) + body_8bitmime = 8; + else if (strcmpic(value, US"7BIT") == 0) + body_8bitmime = 7; + else + { + body_8bitmime = 0; + done = synprot_error(L_smtp_syntax_error, 501, NULL, + US"invalid data for BODY"); + goto COMMAND_LOOP; + } + DEBUG(D_receive) debug_printf("8BITMIME: %d\n", body_8bitmime); + break; + } + arg_error = TRUE; + break; + + /* Handle the two DSN options, but only if configured to do so (which + will have caused "DSN" to be given in the EHLO response). The code itself + is included only if configured in at build time. */ + + case ENV_MAIL_OPT_RET: + if (fl.dsn_advertised) + { + /* Check if RET has already been set */ + if (dsn_ret > 0) + { + done = synprot_error(L_smtp_syntax_error, 501, NULL, + US"RET can be specified once only"); + goto COMMAND_LOOP; + } + dsn_ret = strcmpic(value, US"HDRS") == 0 + ? dsn_ret_hdrs + : strcmpic(value, US"FULL") == 0 + ? dsn_ret_full + : 0; + DEBUG(D_receive) debug_printf("DSN_RET: %d\n", dsn_ret); + /* Check for invalid invalid value, and exit with error */ + if (dsn_ret == 0) + { + done = synprot_error(L_smtp_syntax_error, 501, NULL, + US"Value for RET is invalid"); + goto COMMAND_LOOP; + } + } + break; + case ENV_MAIL_OPT_ENVID: + if (fl.dsn_advertised) + { + /* Check if the dsn envid has been already set */ + if (dsn_envid) + { + done = synprot_error(L_smtp_syntax_error, 501, NULL, + US"ENVID can be specified once only"); + goto COMMAND_LOOP; + } + dsn_envid = string_copy(value); + DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid); + } + break; + + /* Handle the AUTH extension. If the value given is not "<>" and either + the ACL says "yes" or there is no ACL but the sending host is + authenticated, we set it up as the authenticated sender. However, if the + authenticator set a condition to be tested, we ignore AUTH on MAIL unless + the condition is met. The value of AUTH is an xtext, which means that +, + = and cntrl chars are coded in hex; however "<>" is unaffected by this + coding. */ + case ENV_MAIL_OPT_AUTH: + if (Ustrcmp(value, "<>") != 0) + { + int rc; + uschar *ignore_msg; + + if (auth_xtextdecode(value, &authenticated_sender) < 0) + { + /* Put back terminator overrides for error message */ + value[-1] = '='; + name[-1] = ' '; + done = synprot_error(L_smtp_syntax_error, 501, NULL, + US"invalid data for AUTH"); + goto COMMAND_LOOP; + } + if (!acl_smtp_mailauth) + { + ignore_msg = US"client not authenticated"; + rc = sender_host_authenticated ? OK : FAIL; + } + else + { + ignore_msg = US"rejected by ACL"; + rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth, + &user_msg, &log_msg); + } + + switch (rc) + { + case OK: + if (authenticated_by == NULL || + authenticated_by->mail_auth_condition == NULL || + expand_check_condition(authenticated_by->mail_auth_condition, + authenticated_by->name, US"authenticator")) + break; /* Accept the AUTH */ + + ignore_msg = US"server_mail_auth_condition failed"; + if (authenticated_id != NULL) + ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"", + ignore_msg, authenticated_id); + + /* Fall through */ + + case FAIL: + authenticated_sender = NULL; + log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)", + value, host_and_ident(TRUE), ignore_msg); + break; + + /* Should only get DEFER or ERROR here. Put back terminator + overrides for error message */ + + default: + value[-1] = '='; + name[-1] = ' '; + (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg, + log_msg); + goto COMMAND_LOOP; + } + } + break; + +#ifndef DISABLE_PRDR + case ENV_MAIL_OPT_PRDR: + if (prdr_enable) + prdr_requested = TRUE; + break; +#endif + +#ifdef SUPPORT_I18N + case ENV_MAIL_OPT_UTF8: + if (!fl.smtputf8_advertised) + { + done = synprot_error(L_smtp_syntax_error, 501, NULL, + US"SMTPUTF8 used when not advertised"); + goto COMMAND_LOOP; + } + + DEBUG(D_receive) debug_printf("smtputf8 requested\n"); + message_smtputf8 = allow_utf8_domains = TRUE; + if (Ustrncmp(received_protocol, US"utf8", 4) != 0) + { + int old_pool = store_pool; + store_pool = POOL_PERM; + received_protocol = string_sprintf("utf8%s", received_protocol); + store_pool = old_pool; + } + break; +#endif + +#if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS) + case ENV_MAIL_OPT_REQTLS: + { + uschar * r, * t; + + if (!fl.requiretls_advertised) + { + done = synprot_error(L_smtp_syntax_error, 555, NULL, + US"unadvertised MAIL option: REQUIRETLS"); + goto COMMAND_LOOP; + } + + DEBUG(D_receive) debug_printf("requiretls requested\n"); + tls_requiretls = REQUIRETLS_MSG; + + r = string_copy_malloc(received_protocol); + if ((t = Ustrrchr(r, 's'))) *t = 'S'; + received_protocol = r; + } + break; +#endif + + /* No valid option. Stick back the terminator characters and break + the loop. Do the name-terminator second as extract_option sets + value==name when it found no equal-sign. + An error for a malformed address will occur. */ + case ENV_MAIL_OPT_NULL: + value[-1] = '='; + name[-1] = ' '; + arg_error = TRUE; + break; + + default: assert(0); + } + /* Break out of for loop if switch() had bad argument or + when start of the email address is reached */ + if (arg_error) break; + } + +#if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS) + if (tls_requiretls & REQUIRETLS_MSG) + { + /* Ensure headers-only bounces whether a RET option was given or not. */ + + DEBUG(D_receive) if (dsn_ret == dsn_ret_full) + debug_printf("requiretls override: dsn_ret_full -> dsn_ret_hdrs\n"); + dsn_ret = dsn_ret_hdrs; + } +#endif + + /* If we have passed the threshold for rate limiting, apply the current + delay, and update it for next time, provided this is a limited host. */ + + if (smtp_mailcmd_count > smtp_rlm_threshold && + verify_check_host(&smtp_ratelimit_hosts) == OK) + { + DEBUG(D_receive) debug_printf("rate limit MAIL: delay %.3g sec\n", + smtp_delay_mail/1000.0); + millisleep((int)smtp_delay_mail); + smtp_delay_mail *= smtp_rlm_factor; + if (smtp_delay_mail > (double)smtp_rlm_limit) + smtp_delay_mail = (double)smtp_rlm_limit; + } + + /* Now extract the address, first applying any SMTP-time rewriting. The + TRUE flag allows "<>" as a sender address. */ + + raw_sender = rewrite_existflags & rewrite_smtp + ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"", + global_rewrite_rules) + : smtp_cmd_data; + + raw_sender = + parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain, + TRUE); + + if (!raw_sender) + { + done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess); + break; + } + + sender_address = raw_sender; + + /* If there is a configured size limit for mail, check that this message + doesn't exceed it. The check is postponed to this point so that the sender + can be logged. */ + + if (thismessage_size_limit > 0 && message_size > thismessage_size_limit) + { + smtp_printf("552 Message size exceeds maximum permitted\r\n", FALSE); + log_write(L_size_reject, + LOG_MAIN|LOG_REJECT, "rejected MAIL FROM:<%s> %s: " + "message too big: size%s=%d max=%d", + sender_address, + host_and_ident(TRUE), + (message_size == INT_MAX)? ">" : "", + message_size, + thismessage_size_limit); + sender_address = NULL; + break; + } + + /* Check there is enough space on the disk unless configured not to. + When smtp_check_spool_space is set, the check is for thismessage_size_limit + plus the current message - i.e. we accept the message only if it won't + reduce the space below the threshold. Add 5000 to the size to allow for + overheads such as the Received: line and storing of recipients, etc. + By putting the check here, even when SIZE is not given, it allow VRFY + and EXPN etc. to be used when space is short. */ + + if (!receive_check_fs( + (smtp_check_spool_space && message_size >= 0)? + message_size + 5000 : 0)) + { + smtp_printf("452 Space shortage, please try later\r\n", FALSE); + sender_address = NULL; + break; + } + + /* If sender_address is unqualified, reject it, unless this is a locally + generated message, or the sending host or net is permitted to send + unqualified addresses - typically local machines behaving as MUAs - + in which case just qualify the address. The flag is set above at the start + of the SMTP connection. */ + + if (!sender_domain && *sender_address) + if (f.allow_unqualified_sender) + { + sender_domain = Ustrlen(sender_address) + 1; + sender_address = rewrite_address_qualify(sender_address, FALSE); + DEBUG(D_receive) debug_printf("unqualified address %s accepted\n", + raw_sender); + } + else + { + smtp_printf("501 %s: sender address must contain a domain\r\n", FALSE, + smtp_cmd_data); + log_write(L_smtp_syntax_error, + LOG_MAIN|LOG_REJECT, + "unqualified sender rejected: <%s> %s%s", + raw_sender, + host_and_ident(TRUE), + host_lookup_msg); + sender_address = NULL; + break; + } + + /* Apply an ACL check if one is defined, before responding. Afterwards, + when pipelining is not advertised, do another sync check in case the ACL + delayed and the client started sending in the meantime. */ + + if (acl_smtp_mail) + { + rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg); + if (rc == OK && !f.smtp_in_pipelining_advertised && !check_sync()) + goto SYNC_FAILURE; + } + else + rc = OK; + + if (rc == OK || rc == DISCARD) + { + BOOL more = pipeline_response(); + + if (!user_msg) + smtp_printf("%s%s%s", more, US"250 OK", + #ifndef DISABLE_PRDR + prdr_requested ? US", PRDR Requested" : US"", + #else + US"", + #endif + US"\r\n"); + else + { + #ifndef DISABLE_PRDR + if (prdr_requested) + user_msg = string_sprintf("%s%s", user_msg, US", PRDR Requested"); + #endif + smtp_user_msg(US"250", user_msg); + } + smtp_delay_rcpt = smtp_rlr_base; + f.recipients_discarded = (rc == DISCARD); + was_rej_mail = FALSE; + } + else + { + done = smtp_handle_acl_fail(ACL_WHERE_MAIL, rc, user_msg, log_msg); + sender_address = NULL; + } + break; + + + /* The RCPT command requires an address as an operand. There may be any + number of RCPT commands, specifying multiple recipients. We build them all + into a data structure. The start/end values given by parse_extract_address + are not used, as we keep only the extracted address. */ + + case RCPT_CMD: + HAD(SCH_RCPT); + rcpt_count++; + was_rcpt = fl.rcpt_in_progress = TRUE; + + /* There must be a sender address; if the sender was rejected and + pipelining was advertised, we assume the client was pipelining, and do not + count this as a protocol error. Reset was_rej_mail so that further RCPTs + get the same treatment. */ + + if (sender_address == NULL) + { + if (f.smtp_in_pipelining_advertised && last_was_rej_mail) + { + smtp_printf("503 sender not yet given\r\n", FALSE); + was_rej_mail = TRUE; + } + else + { + done = synprot_error(L_smtp_protocol_error, 503, NULL, + US"sender not yet given"); + was_rcpt = FALSE; /* Not a valid RCPT */ + } + rcpt_fail_count++; + break; + } + + /* Check for an operand */ + + if (smtp_cmd_data[0] == 0) + { + done = synprot_error(L_smtp_syntax_error, 501, NULL, + US"RCPT must have an address operand"); + rcpt_fail_count++; + break; + } + + /* Set the DSN flags orcpt and dsn_flags from the session*/ + orcpt = NULL; + dsn_flags = 0; + + if (fl.esmtp) for(;;) + { + uschar *name, *value; + + if (!extract_option(&name, &value)) + break; + + if (fl.dsn_advertised && strcmpic(name, US"ORCPT") == 0) + { + /* Check whether orcpt has been already set */ + if (orcpt) + { + done = synprot_error(L_smtp_syntax_error, 501, NULL, + US"ORCPT can be specified once only"); + goto COMMAND_LOOP; + } + orcpt = string_copy(value); + DEBUG(D_receive) debug_printf("DSN orcpt: %s\n", orcpt); + } + + else if (fl.dsn_advertised && strcmpic(name, US"NOTIFY") == 0) + { + /* Check if the notify flags have been already set */ + if (dsn_flags > 0) + { + done = synprot_error(L_smtp_syntax_error, 501, NULL, + US"NOTIFY can be specified once only"); + goto COMMAND_LOOP; + } + if (strcmpic(value, US"NEVER") == 0) + dsn_flags |= rf_notify_never; + else + { + uschar *p = value; + while (*p != 0) + { + uschar *pp = p; + while (*pp != 0 && *pp != ',') pp++; + if (*pp == ',') *pp++ = 0; + if (strcmpic(p, US"SUCCESS") == 0) + { + DEBUG(D_receive) debug_printf("DSN: Setting notify success\n"); + dsn_flags |= rf_notify_success; + } + else if (strcmpic(p, US"FAILURE") == 0) + { + DEBUG(D_receive) debug_printf("DSN: Setting notify failure\n"); + dsn_flags |= rf_notify_failure; + } + else if (strcmpic(p, US"DELAY") == 0) + { + DEBUG(D_receive) debug_printf("DSN: Setting notify delay\n"); + dsn_flags |= rf_notify_delay; + } + else + { + /* Catch any strange values */ + done = synprot_error(L_smtp_syntax_error, 501, NULL, + US"Invalid value for NOTIFY parameter"); + goto COMMAND_LOOP; + } + p = pp; + } + DEBUG(D_receive) debug_printf("DSN Flags: %x\n", dsn_flags); + } + } + + /* Unknown option. Stick back the terminator characters and break + the loop. An error for a malformed address will occur. */ + + else + { + DEBUG(D_receive) debug_printf("Invalid RCPT option: %s : %s\n", name, value); + name[-1] = ' '; + value[-1] = '='; + break; + } + } + + /* Apply SMTP rewriting then extract the working address. Don't allow "<>" + as a recipient address */ + + recipient = rewrite_existflags & rewrite_smtp + ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"", + global_rewrite_rules) + : smtp_cmd_data; + + if (!(recipient = parse_extract_address(recipient, &errmess, &start, &end, + &recipient_domain, FALSE))) + { + done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess); + rcpt_fail_count++; + break; + } + + /* If the recipient address is unqualified, reject it, unless this is a + locally generated message. However, unqualified addresses are permitted + from a configured list of hosts and nets - typically when behaving as + MUAs rather than MTAs. Sad that SMTP is used for both types of traffic, + really. The flag is set at the start of the SMTP connection. + + RFC 1123 talks about supporting "the reserved mailbox postmaster"; I always + assumed this meant "reserved local part", but the revision of RFC 821 and + friends now makes it absolutely clear that it means *mailbox*. Consequently + we must always qualify this address, regardless. */ + + if (!recipient_domain) + if (!(recipient_domain = qualify_recipient(&recipient, smtp_cmd_data, + US"recipient"))) + { + rcpt_fail_count++; + break; + } + + /* Check maximum allowed */ + + if (rcpt_count > recipients_max && recipients_max > 0) + { + if (recipients_max_reject) + { + rcpt_fail_count++; + smtp_printf("552 too many recipients\r\n", FALSE); + if (!toomany) + log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: message " + "rejected: sender=<%s> %s", sender_address, host_and_ident(TRUE)); + } + else + { + rcpt_defer_count++; + smtp_printf("452 too many recipients\r\n", FALSE); + if (!toomany) + log_write(0, LOG_MAIN|LOG_REJECT, "too many recipients: excess " + "temporarily rejected: sender=<%s> %s", sender_address, + host_and_ident(TRUE)); + } + + toomany = TRUE; + break; + } + + /* If we have passed the threshold for rate limiting, apply the current + delay, and update it for next time, provided this is a limited host. */ + + if (rcpt_count > smtp_rlr_threshold && + verify_check_host(&smtp_ratelimit_hosts) == OK) + { + DEBUG(D_receive) debug_printf("rate limit RCPT: delay %.3g sec\n", + smtp_delay_rcpt/1000.0); + millisleep((int)smtp_delay_rcpt); + smtp_delay_rcpt *= smtp_rlr_factor; + if (smtp_delay_rcpt > (double)smtp_rlr_limit) + smtp_delay_rcpt = (double)smtp_rlr_limit; + } + + /* If the MAIL ACL discarded all the recipients, we bypass ACL checking + for them. Otherwise, check the access control list for this recipient. As + there may be a delay in this, re-check for a synchronization error + afterwards, unless pipelining was advertised. */ + + if (f.recipients_discarded) + rc = DISCARD; + else + if ( (rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, + &log_msg)) == OK + && !f.smtp_in_pipelining_advertised && !check_sync()) + goto SYNC_FAILURE; + + /* The ACL was happy */ + + if (rc == OK) + { + BOOL more = pipeline_response(); + + if (user_msg) + smtp_user_msg(US"250", user_msg); + else + smtp_printf("250 Accepted\r\n", more); + receive_add_recipient(recipient, -1); + + /* Set the dsn flags in the recipients_list */ + recipients_list[recipients_count-1].orcpt = orcpt; + recipients_list[recipients_count-1].dsn_flags = dsn_flags; + + DEBUG(D_receive) debug_printf("DSN: orcpt: %s flags: %d\n", + recipients_list[recipients_count-1].orcpt, + recipients_list[recipients_count-1].dsn_flags); + } + + /* The recipient was discarded */ + + else if (rc == DISCARD) + { + if (user_msg) + smtp_user_msg(US"250", user_msg); + else + smtp_printf("250 Accepted\r\n", FALSE); + rcpt_fail_count++; + discarded = TRUE; + log_write(0, LOG_MAIN|LOG_REJECT, "%s F=<%s> RCPT %s: " + "discarded by %s ACL%s%s", host_and_ident(TRUE), + sender_address_unrewritten? sender_address_unrewritten : sender_address, + smtp_cmd_argument, f.recipients_discarded? "MAIL" : "RCPT", + log_msg ? US": " : US"", log_msg ? log_msg : US""); + } + + /* Either the ACL failed the address, or it was deferred. */ + + else + { + if (rc == FAIL) rcpt_fail_count++; else rcpt_defer_count++; + done = smtp_handle_acl_fail(ACL_WHERE_RCPT, rc, user_msg, log_msg); + } + break; + + + /* The DATA command is legal only if it follows successful MAIL FROM + and RCPT TO commands. However, if pipelining is advertised, a bad DATA is + not counted as a protocol error if it follows RCPT (which must have been + rejected if there are no recipients.) This function is complete when a + valid DATA command is encountered. + + Note concerning the code used: RFC 2821 says this: + + - If there was no MAIL, or no RCPT, command, or all such commands + were rejected, the server MAY return a "command out of sequence" + (503) or "no valid recipients" (554) reply in response to the + DATA command. + + The example in the pipelining RFC 2920 uses 554, but I use 503 here + because it is the same whether pipelining is in use or not. + + If all the RCPT commands that precede DATA provoked the same error message + (often indicating some kind of system error), it is helpful to include it + with the DATA rejection (an idea suggested by Tony Finch). */ + + case BDAT_CMD: + { + int n; + + HAD(SCH_BDAT); + if (chunking_state != CHUNKING_OFFERED) + { + done = synprot_error(L_smtp_protocol_error, 503, NULL, + US"BDAT command used when CHUNKING not advertised"); + break; + } + + /* grab size, endmarker */ + + if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1) + { + done = synprot_error(L_smtp_protocol_error, 501, NULL, + US"missing size for BDAT command"); + break; + } + chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0 + ? CHUNKING_LAST : CHUNKING_ACTIVE; + chunking_data_left = chunking_datasize; + DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n", + (int)chunking_state, chunking_data_left); + + /* push the current receive_* function on the "stack", and + replace them by bdat_getc(), which in turn will use the lwr_receive_* + functions to do the dirty work. */ + lwr_receive_getc = receive_getc; + lwr_receive_getbuf = receive_getbuf; + lwr_receive_ungetc = receive_ungetc; + + receive_getc = bdat_getc; + receive_ungetc = bdat_ungetc; + + f.dot_ends = FALSE; + + goto DATA_BDAT; + } + + case DATA_CMD: + HAD(SCH_DATA); + f.dot_ends = TRUE; + + DATA_BDAT: /* Common code for DATA and BDAT */ +#ifdef EXPERIMENTAL_PIPE_CONNECT + fl.pipe_connect_acceptable = FALSE; +#endif + if (!discarded && recipients_count <= 0) + { + if (fl.rcpt_smtp_response_same && rcpt_smtp_response != NULL) + { + uschar *code = US"503"; + int len = Ustrlen(rcpt_smtp_response); + smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with " + "this error:"); + /* Responses from smtp_printf() will have \r\n on the end */ + if (len > 2 && rcpt_smtp_response[len-2] == '\r') + rcpt_smtp_response[len-2] = 0; + smtp_respond(code, 3, FALSE, rcpt_smtp_response); + } + if (f.smtp_in_pipelining_advertised && last_was_rcpt) + smtp_printf("503 Valid RCPT command must precede %s\r\n", FALSE, + smtp_names[smtp_connection_had[smtp_ch_index-1]]); + else + done = synprot_error(L_smtp_protocol_error, 503, NULL, + smtp_connection_had[smtp_ch_index-1] == SCH_DATA + ? US"valid RCPT command must precede DATA" + : US"valid RCPT command must precede BDAT"); + + if (chunking_state > CHUNKING_OFFERED) + bdat_flush_data(); + break; + } + + if (toomany && recipients_max_reject) + { + sender_address = NULL; /* This will allow a new MAIL without RSET */ + sender_address_unrewritten = NULL; + smtp_printf("554 Too many recipients\r\n", FALSE); + break; + } + + if (chunking_state > CHUNKING_OFFERED) + rc = OK; /* No predata ACL or go-ahead output for BDAT */ + else + { + /* If there is an ACL, re-check the synchronization afterwards, since the + ACL may have delayed. To handle cutthrough delivery enforce a dummy call + to get the DATA command sent. */ + + if (acl_smtp_predata == NULL && cutthrough.cctx.sock < 0) + rc = OK; + else + { + uschar * acl = acl_smtp_predata ? acl_smtp_predata : US"accept"; + f.enable_dollar_recipients = TRUE; + rc = acl_check(ACL_WHERE_PREDATA, NULL, acl, &user_msg, + &log_msg); + f.enable_dollar_recipients = FALSE; + if (rc == OK && !check_sync()) + goto SYNC_FAILURE; + + if (rc != OK) + { /* Either the ACL failed the address, or it was deferred. */ + done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg); + break; + } + } + + if (user_msg) + smtp_user_msg(US"354", user_msg); + else + smtp_printf( + "354 Enter message, ending with \".\" on a line by itself\r\n", FALSE); + } + +#ifdef TCP_QUICKACK + if (smtp_in) /* all ACKs needed to ramp window up for bulk data */ + (void) setsockopt(fileno(smtp_in), IPPROTO_TCP, TCP_QUICKACK, + US &on, sizeof(on)); +#endif + done = 3; + message_ended = END_NOTENDED; /* Indicate in middle of data */ + + break; + + + case VRFY_CMD: + { + uschar * address; + + HAD(SCH_VRFY); + + if (!(address = parse_extract_address(smtp_cmd_data, &errmess, + &start, &end, &recipient_domain, FALSE))) + { + smtp_printf("501 %s\r\n", FALSE, errmess); + break; + } + + if (!recipient_domain) + if (!(recipient_domain = qualify_recipient(&address, smtp_cmd_data, + US"verify"))) + break; + + if ((rc = acl_check(ACL_WHERE_VRFY, address, acl_smtp_vrfy, + &user_msg, &log_msg)) != OK) + done = smtp_handle_acl_fail(ACL_WHERE_VRFY, rc, user_msg, log_msg); + else + { + uschar * s = NULL; + address_item * addr = deliver_make_addr(address, FALSE); + + switch(verify_address(addr, NULL, vopt_is_recipient | vopt_qualify, -1, + -1, -1, NULL, NULL, NULL)) + { + case OK: + s = string_sprintf("250 <%s> is deliverable", address); + break; + + case DEFER: + s = (addr->user_message != NULL)? + string_sprintf("451 <%s> %s", address, addr->user_message) : + string_sprintf("451 Cannot resolve <%s> at this time", address); + break; + + case FAIL: + s = (addr->user_message != NULL)? + string_sprintf("550 <%s> %s", address, addr->user_message) : + string_sprintf("550 <%s> is not deliverable", address); + log_write(0, LOG_MAIN, "VRFY failed for %s %s", + smtp_cmd_argument, host_and_ident(TRUE)); + break; + } + + smtp_printf("%s\r\n", FALSE, s); + } + break; + } + + + case EXPN_CMD: + HAD(SCH_EXPN); + rc = acl_check(ACL_WHERE_EXPN, NULL, acl_smtp_expn, &user_msg, &log_msg); + if (rc != OK) + done = smtp_handle_acl_fail(ACL_WHERE_EXPN, rc, user_msg, log_msg); + else + { + BOOL save_log_testing_mode = f.log_testing_mode; + f.address_test_mode = f.log_testing_mode = TRUE; + (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE), + smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1, + NULL, NULL, NULL); + f.address_test_mode = FALSE; + f.log_testing_mode = save_log_testing_mode; /* true for -bh */ + } + break; + + + #ifdef SUPPORT_TLS + + case STARTTLS_CMD: + HAD(SCH_STARTTLS); + if (!fl.tls_advertised) + { + done = synprot_error(L_smtp_protocol_error, 503, NULL, + US"STARTTLS command used when not advertised"); + break; + } + + /* Apply an ACL check if one is defined */ + + if ( acl_smtp_starttls + && (rc = acl_check(ACL_WHERE_STARTTLS, NULL, acl_smtp_starttls, + &user_msg, &log_msg)) != OK + ) + { + done = smtp_handle_acl_fail(ACL_WHERE_STARTTLS, rc, user_msg, log_msg); + break; + } + + /* RFC 2487 is not clear on when this command may be sent, though it + does state that all information previously obtained from the client + must be discarded if a TLS session is started. It seems reasonable to + do an implied RSET when STARTTLS is received. */ + + incomplete_transaction_log(US"STARTTLS"); + cancel_cutthrough_connection(TRUE, US"STARTTLS received"); + smtp_reset(reset_point); + toomany = FALSE; + cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE; + + /* There's an attack where more data is read in past the STARTTLS command + before TLS is negotiated, then assumed to be part of the secure session + when used afterwards; we use segregated input buffers, so are not + vulnerable, but we want to note when it happens and, for sheer paranoia, + ensure that the buffer is "wiped". + Pipelining sync checks will normally have protected us too, unless disabled + by configuration. */ + + if (receive_smtp_buffered()) + { + DEBUG(D_any) + debug_printf("Non-empty input buffer after STARTTLS; naive attack?\n"); + if (tls_in.active.sock < 0) + smtp_inend = smtp_inptr = smtp_inbuffer; + /* and if TLS is already active, tls_server_start() should fail */ + } + + /* There is nothing we value in the input buffer and if TLS is successfully + negotiated, we won't use this buffer again; if TLS fails, we'll just read + fresh content into it. The buffer contains arbitrary content from an + untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n + It seems safest to just wipe away the content rather than leave it as a + target to jump to. */ + + memset(smtp_inbuffer, 0, IN_BUFFER_SIZE); + + /* Attempt to start up a TLS session, and if successful, discard all + knowledge that was obtained previously. At least, that's what the RFC says, + and that's what happens by default. However, in order to work round YAEB, + there is an option to remember the esmtp state. Sigh. + + We must allow for an extra EHLO command and an extra AUTH command after + STARTTLS that don't add to the nonmail command count. */ + + s = NULL; + if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK) + { + if (!tls_remember_esmtp) + fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE; + cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE; + cmd_list[CMD_LIST_AUTH].is_mail_cmd = TRUE; + cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE; + if (sender_helo_name) + { + store_free(sender_helo_name); + sender_helo_name = NULL; + host_build_sender_fullhost(); /* Rebuild */ + set_process_info("handling incoming TLS connection from %s", + host_and_ident(FALSE)); + } + received_protocol = + (sender_host_address ? protocols : protocols_local) + [ (fl.esmtp + ? pextend + (sender_host_authenticated ? pauthed : 0) + : pnormal) + + (tls_in.active.sock >= 0 ? pcrpted : 0) + ]; + + sender_host_auth_pubname = sender_host_authenticated = NULL; + authenticated_id = NULL; + sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING; + DEBUG(D_tls) debug_printf("TLS active\n"); + break; /* Successful STARTTLS */ + } + else + (void) smtp_log_tls_fail(s); + + /* Some local configuration problem was discovered before actually trying + to do a TLS handshake; give a temporary error. */ + + if (rc == DEFER) + { + smtp_printf("454 TLS currently unavailable\r\n", FALSE); + break; + } + + /* Hard failure. Reject everything except QUIT or closed connection. One + cause for failure is a nested STARTTLS, in which case tls_in.active remains + set, but we must still reject all incoming commands. Another is a handshake + failure - and there may some encrypted data still in the pipe to us, which we + see as garbage commands. */ + + DEBUG(D_tls) debug_printf("TLS failed to start\n"); + while (done <= 0) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED)) + { + case EOF_CMD: + log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF", + smtp_get_connection_info()); + smtp_notquit_exit(US"tls-failed", NULL, NULL); + done = 2; + break; + + /* It is perhaps arguable as to which exit ACL should be called here, + but as it is probably a situation that almost never arises, it + probably doesn't matter. We choose to call the real QUIT ACL, which in + some sense is perhaps "right". */ + + case QUIT_CMD: + user_msg = NULL; + if ( acl_smtp_quit + && ((rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, + &log_msg)) == ERROR)) + log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s", + log_msg); + if (user_msg) + smtp_respond(US"221", 3, TRUE, user_msg); + else + smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname); + log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT", + smtp_get_connection_info()); + done = 2; + break; + + default: + smtp_printf("554 Security failure\r\n", FALSE); + break; + } + tls_close(NULL, TLS_SHUTDOWN_NOWAIT); + break; + #endif + + + /* The ACL for QUIT is provided for gathering statistical information or + similar; it does not affect the response code, but it can supply a custom + message. */ + + case QUIT_CMD: + smtp_quit_handler(&user_msg, &log_msg); + done = 2; + break; + + + case RSET_CMD: + smtp_rset_handler(); + cancel_cutthrough_connection(TRUE, US"RSET received"); + smtp_reset(reset_point); + toomany = FALSE; + break; + + + case NOOP_CMD: + HAD(SCH_NOOP); + smtp_printf("250 OK\r\n", FALSE); + break; + + + /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually + used, a check will be done for permitted hosts. Show STARTTLS only if not + already in a TLS session and if it would be advertised in the EHLO + response. */ + + case HELP_CMD: + HAD(SCH_HELP); + smtp_printf("214-Commands supported:\r\n", TRUE); + { + uschar buffer[256]; + buffer[0] = 0; + Ustrcat(buffer, " AUTH"); + #ifdef SUPPORT_TLS + if (tls_in.active.sock < 0 && + verify_check_host(&tls_advertise_hosts) != FAIL) + Ustrcat(buffer, " STARTTLS"); + #endif + Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA BDAT"); + Ustrcat(buffer, " NOOP QUIT RSET HELP"); + if (acl_smtp_etrn != NULL) Ustrcat(buffer, " ETRN"); + if (acl_smtp_expn != NULL) Ustrcat(buffer, " EXPN"); + if (acl_smtp_vrfy != NULL) Ustrcat(buffer, " VRFY"); + smtp_printf("214%s\r\n", FALSE, buffer); + } + break; + + + case EOF_CMD: + incomplete_transaction_log(US"connection lost"); + smtp_notquit_exit(US"connection-lost", US"421", + US"%s lost input connection", smtp_active_hostname); + + /* Don't log by default unless in the middle of a message, as some mailers + just drop the call rather than sending QUIT, and it clutters up the logs. + */ + + if (sender_address || recipients_count > 0) + log_write(L_lost_incoming_connection, LOG_MAIN, + "unexpected %s while reading SMTP command from %s%s%s D=%s", + f.sender_host_unknown ? "EOF" : "disconnection", + f.tcp_in_fastopen_logged + ? US"" + : f.tcp_in_fastopen + ? f.tcp_in_fastopen_data ? US"TFO* " : US"TFO " + : US"", + host_and_ident(FALSE), smtp_read_error, + string_timesince(&smtp_connection_start) + ); + + else + log_write(L_smtp_connection, LOG_MAIN, "%s %slost%s D=%s", + smtp_get_connection_info(), + f.tcp_in_fastopen && !f.tcp_in_fastopen_logged ? US"TFO " : US"", + smtp_read_error, + string_timesince(&smtp_connection_start) + ); + + done = 1; + break; + + + case ETRN_CMD: + HAD(SCH_ETRN); + if (sender_address) + { + done = synprot_error(L_smtp_protocol_error, 503, NULL, + US"ETRN is not permitted inside a transaction"); + break; + } + + log_write(L_etrn, LOG_MAIN, "ETRN %s received from %s", smtp_cmd_argument, + host_and_ident(FALSE)); + + if ((rc = acl_check(ACL_WHERE_ETRN, NULL, acl_smtp_etrn, + &user_msg, &log_msg)) != OK) + { + done = smtp_handle_acl_fail(ACL_WHERE_ETRN, rc, user_msg, log_msg); + break; + } + + /* Compute the serialization key for this command. */ + + etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data); + + /* If a command has been specified for running as a result of ETRN, we + permit any argument to ETRN. If not, only the # standard form is permitted, + since that is strictly the only kind of ETRN that can be implemented + according to the RFC. */ + + if (smtp_etrn_command) + { + uschar *error; + BOOL rc; + etrn_command = smtp_etrn_command; + deliver_domain = smtp_cmd_data; + rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL, + US"ETRN processing", &error); + deliver_domain = NULL; + if (!rc) + { + log_write(0, LOG_MAIN|LOG_PANIC, "failed to set up ETRN command: %s", + error); + smtp_printf("458 Internal failure\r\n", FALSE); + break; + } + } + + /* Else set up to call Exim with the -R option. */ + + else + { + if (*smtp_cmd_data++ != '#') + { + done = synprot_error(L_smtp_syntax_error, 501, NULL, + US"argument must begin with #"); + break; + } + etrn_command = US"exim -R"; + argv = CUSS child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, + *queue_name ? 4 : 2, + US"-R", smtp_cmd_data, + US"-MCG", queue_name); + } + + /* If we are host-testing, don't actually do anything. */ + + if (host_checking) + { + HDEBUG(D_any) + { + debug_printf("ETRN command is: %s\n", etrn_command); + debug_printf("ETRN command execution skipped\n"); + } + if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE); + else smtp_user_msg(US"250", user_msg); + break; + } + + + /* If ETRN queue runs are to be serialized, check the database to + ensure one isn't already running. */ + + if (smtp_etrn_serialize && !enq_start(etrn_serialize_key, 1)) + { + smtp_printf("458 Already processing %s\r\n", FALSE, smtp_cmd_data); + break; + } + + /* Fork a child process and run the command. We don't want to have to + wait for the process at any point, so set SIGCHLD to SIG_IGN before + forking. It should be set that way anyway for external incoming SMTP, + but we save and restore to be tidy. If serialization is required, we + actually run the command in yet another process, so we can wait for it + to complete and then remove the serialization lock. */ + + oldsignal = signal(SIGCHLD, SIG_IGN); + + if ((pid = fork()) == 0) + { + smtp_input = FALSE; /* This process is not associated with the */ + (void)fclose(smtp_in); /* SMTP call any more. */ + (void)fclose(smtp_out); + + signal(SIGCHLD, SIG_DFL); /* Want to catch child */ + + /* If not serializing, do the exec right away. Otherwise, fork down + into another process. */ + + if (!smtp_etrn_serialize || (pid = fork()) == 0) + { + DEBUG(D_exec) debug_print_argv(argv); + exim_nullstd(); /* Ensure std{in,out,err} exist */ + execv(CS argv[0], (char *const *)argv); + log_write(0, LOG_MAIN|LOG_PANIC_DIE, "exec of \"%s\" (ETRN) failed: %s", + etrn_command, strerror(errno)); + _exit(EXIT_FAILURE); /* paranoia */ + } + + /* Obey this if smtp_serialize and the 2nd fork yielded non-zero. That + is, we are in the first subprocess, after forking again. All we can do + for a failing fork is to log it. Otherwise, wait for the 2nd process to + complete, before removing the serialization. */ + + if (pid < 0) + log_write(0, LOG_MAIN|LOG_PANIC, "2nd fork for serialized ETRN " + "failed: %s", strerror(errno)); + else + { + int status; + DEBUG(D_any) debug_printf("waiting for serialized ETRN process %d\n", + (int)pid); + (void)wait(&status); + DEBUG(D_any) debug_printf("serialized ETRN process %d ended\n", + (int)pid); + } + + enq_end(etrn_serialize_key); + _exit(EXIT_SUCCESS); + } + + /* Back in the top level SMTP process. Check that we started a subprocess + and restore the signal state. */ + + if (pid < 0) + { + log_write(0, LOG_MAIN|LOG_PANIC, "fork of process for ETRN failed: %s", + strerror(errno)); + smtp_printf("458 Unable to fork process\r\n", FALSE); + if (smtp_etrn_serialize) enq_end(etrn_serialize_key); + } + else + { + if (user_msg == NULL) smtp_printf("250 OK\r\n", FALSE); + else smtp_user_msg(US"250", user_msg); + } + + signal(SIGCHLD, oldsignal); + break; + + + case BADARG_CMD: + done = synprot_error(L_smtp_syntax_error, 501, NULL, + US"unexpected argument data"); + break; + + + /* This currently happens only for NULLs, but could be extended. */ + + case BADCHAR_CMD: + done = synprot_error(L_smtp_syntax_error, 0, NULL, /* Just logs */ + US"NUL character(s) present (shown as '?')"); + smtp_printf("501 NUL characters are not allowed in SMTP commands\r\n", + FALSE); + break; + + + case BADSYN_CMD: + SYNC_FAILURE: + if (smtp_inend >= smtp_inbuffer + IN_BUFFER_SIZE) + smtp_inend = smtp_inbuffer + IN_BUFFER_SIZE - 1; + c = smtp_inend - smtp_inptr; + if (c > 150) c = 150; /* limit logged amount */ + smtp_inptr[c] = 0; + incomplete_transaction_log(US"sync failure"); + log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error " + "(next input sent too soon: pipelining was%s advertised): " + "rejected \"%s\" %s next input=\"%s\"", + f.smtp_in_pipelining_advertised ? "" : " not", + smtp_cmd_buffer, host_and_ident(TRUE), + string_printing(smtp_inptr)); + smtp_notquit_exit(US"synchronization-error", US"554", + US"SMTP synchronization error"); + done = 1; /* Pretend eof - drops connection */ + break; + + + case TOO_MANY_NONMAIL_CMD: + s = smtp_cmd_buffer; + while (*s != 0 && !isspace(*s)) s++; + incomplete_transaction_log(US"too many non-mail commands"); + log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " + "nonmail commands (last was \"%.*s\")", host_and_ident(FALSE), + (int)(s - smtp_cmd_buffer), smtp_cmd_buffer); + smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands"); + done = 1; /* Pretend eof - drops connection */ + break; + +#ifdef SUPPORT_PROXY + case PROXY_FAIL_IGNORE_CMD: + smtp_printf("503 Command refused, required Proxy negotiation failed\r\n", FALSE); + break; +#endif + + default: + if (unknown_command_count++ >= smtp_max_unknown_commands) + { + log_write(L_smtp_syntax_error, LOG_MAIN, + "SMTP syntax error in \"%s\" %s %s", + string_printing(smtp_cmd_buffer), host_and_ident(TRUE), + US"unrecognized command"); + incomplete_transaction_log(US"unrecognized command"); + smtp_notquit_exit(US"bad-commands", US"500", + US"Too many unrecognized commands"); + done = 2; + log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many " + "unrecognized commands (last was \"%s\")", host_and_ident(FALSE), + string_printing(smtp_cmd_buffer)); + } + else + done = synprot_error(L_smtp_syntax_error, 500, NULL, + US"unrecognized command"); + break; + } + + /* This label is used by goto's inside loops that want to break out to + the end of the command-processing loop. */ + + COMMAND_LOOP: + last_was_rej_mail = was_rej_mail; /* Remember some last commands for */ + last_was_rcpt = was_rcpt; /* protocol error handling */ + continue; + } + +return done - 2; /* Convert yield values */ +} + + + +gstring * +authres_smtpauth(gstring * g) +{ +if (!sender_host_authenticated) + return g; + +g = string_append(g, 2, US";\n\tauth=pass (", sender_host_auth_pubname); + +if (Ustrcmp(sender_host_auth_pubname, "tls") != 0) + g = string_append(g, 2, US") smtp.auth=", authenticated_id); +else if (authenticated_id) + g = string_append(g, 2, US") x509.auth=", authenticated_id); +else + g = string_catn(g, US") reason=x509.auth", 17); + +if (authenticated_sender) + g = string_append(g, 2, US" smtp.mailfrom=", authenticated_sender); +return g; +} + + + +/* vi: aw ai sw=2 +*/ +/* End of smtp_in.c */ |