piler/src/session.c
2013-09-11 09:19:29 +02:00

590 lines
18 KiB
C

/*
* session.c, SJ
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <signal.h>
#include <syslog.h>
#include <time.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
#include <piler.h>
int handle_smtp_session(int new_sd, struct __data *data, struct __config *cfg){
int i, ret, pos, n, inj=ERR, state, prevlen=0;
char *p, buf[MAXBUFSIZE], puf[MAXBUFSIZE], resp[MAXBUFSIZE], prevbuf[MAXBUFSIZE], last2buf[2*MAXBUFSIZE+1];
char rcpttoemail[SMALLBUFSIZE], virusinfo[SMALLBUFSIZE], delay[SMALLBUFSIZE];
char *arule = NULL;
struct session_data sdata;
struct _state sstate;
int db_conn=0;
int rc;
struct __counters counters;
struct timezone tz;
struct timeval tv1, tv2;
#ifdef HAVE_STARTTLS
int starttls = 0;
char ssl_error[SMALLBUFSIZE];
#endif
#ifdef HAVE_LIBWRAP
struct request_info req;
request_init(&req, RQ_DAEMON, PROGNAME, RQ_FILE, new_sd, 0);
fromhost(&req);
if(!hosts_access(&req)){
send(new_sd, SMTP_RESP_550_ERR_YOU_ARE_BANNED_BY_LOCAL_POLICY, strlen(SMTP_RESP_550_ERR_YOU_ARE_BANNED_BY_LOCAL_POLICY), 0);
syslog(LOG_PRIORITY, "denied connection from %s by tcp_wrappers", eval_client(&req));
return 0;
}
#endif
srand(getpid());
state = SMTP_STATE_INIT;
init_session_data(&sdata, cfg);
sdata.tls = 0;
bzero(&counters, sizeof(counters));
/* open database connection */
db_conn = 0;
#ifdef NEED_MYSQL
if(open_database(&sdata, cfg) == OK){
db_conn = 1;
}
else
syslog(LOG_PRIORITY, "%s", ERR_MYSQL_CONNECT);
#endif
if(db_conn == 0){
send(new_sd, SMTP_RESP_421_ERR_TMP, strlen(SMTP_RESP_421_ERR_TMP), 0);
syslog(LOG_PRIORITY, "cannot make prepared statement");
return 0;
}
gettimeofday(&tv1, &tz);
#ifdef HAVE_LMTP
snprintf(buf, MAXBUFSIZE-1, LMTP_RESP_220_BANNER, cfg->hostid);
#else
snprintf(buf, MAXBUFSIZE-1, SMTP_RESP_220_BANNER, cfg->hostid);
#endif
send(new_sd, buf, strlen(buf), 0);
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: sent: %s", sdata.ttmpfile, buf);
while((n = recvtimeoutssl(new_sd, puf, MAXBUFSIZE, TIMEOUT, sdata.tls, data->ssl)) > 0){
pos = 0;
/* accept mail data */
if(state == SMTP_STATE_DATA){
/* join the last 2 buffer */
memset(last2buf, 0, 2*MAXBUFSIZE+1);
memcpy(last2buf, prevbuf, MAXBUFSIZE);
memcpy(last2buf+prevlen, puf, MAXBUFSIZE);
pos = searchStringInBuffer(last2buf, 2*MAXBUFSIZE+1, SMTP_CMD_PERIOD, 5);
if(pos > 0){
/* fix position */
pos = pos - prevlen;
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: period found", sdata.ttmpfile);
/* write data only to (and including) the trailing period (.) */
ret = write(sdata.fd, puf, pos);
sdata.tot_len += ret;
/* fix posistion! */
pos += strlen(SMTP_CMD_PERIOD);
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: got: (.)", sdata.ttmpfile);
state = SMTP_STATE_PERIOD;
/* make sure we had a successful read */
rc = fsync(sdata.fd);
close(sdata.fd);
gettimeofday(&tv2, &tz);
sdata.__acquire = tvdiff(tv2, tv1);
if(rc){
syslog(LOG_PRIORITY, "failed writing data: %s", sdata.ttmpfile);
#ifdef HAVE_LMTP
for(i=0; i<sdata.num_of_rcpt_to; i++){
#endif
write1(new_sd, SMTP_RESP_421_ERR_WRITE_FAILED, strlen(SMTP_RESP_421_ERR_WRITE_FAILED), sdata.tls, data->ssl);
#ifdef HAVE_LMTP
}
#endif
memset(puf, 0, MAXBUFSIZE);
goto AFTER_PERIOD;
}
gettimeofday(&tv1, &tz);
sstate = parse_message(&sdata, 1, data, cfg);
post_parse(&sdata, &sstate, cfg);
gettimeofday(&tv2, &tz);
sdata.__parsed = tvdiff(tv2, tv1);
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: parsed message", sdata.ttmpfile);
if(cfg->archive_only_mydomains == 1 && sdata.internal_sender == 0 && sdata.internal_recipient == 0){
remove_stripped_attachments(&sstate);
inj = ERR_MYDOMAINS;
snprintf(sdata.acceptbuf, SMALLBUFSIZE-1, "250 Ok %s <%s>\r\n", sdata.ttmpfile, rcpttoemail);
write1(new_sd, sdata.acceptbuf, strlen(sdata.acceptbuf), sdata.tls, data->ssl);
syslog(LOG_PRIORITY, "%s: discarding: not on mydomains, from=%s, message-id=%s", sdata.ttmpfile, sdata.fromemail, sstate.message_id);
goto END_OF_PROCESSING;
}
sdata.need_scan = 1;
make_digests(&sdata, cfg);
#ifdef HAVE_ANTIVIRUS
if(cfg->use_antivirus == 1){
gettimeofday(&tv1, &tz);
sdata.rav = do_av_check(&sdata, rcpttoemail, &virusinfo[0], data, cfg);
gettimeofday(&tv2, &tz);
sdata.__av = tvdiff(tv2, tv1);
}
#endif
#ifdef HAVE_LMTP
for(i=0; i<sdata.num_of_rcpt_to; i++){
#else
i = 0;
#endif
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: round %d in injection", sdata.ttmpfile, i);
extractEmail(sdata.rcptto[i], rcpttoemail);
/* copy default config to enable policy support */
//memcpy(&my_cfg, cfg, sizeof(struct __config));
inj = ERR;
if(db_conn == 1){
if(sdata.restored_copy == 1){
syslog(LOG_PRIORITY, "%s: discarding: restored copy", sdata.ttmpfile);
inj = OK;
}
else if(AVIR_VIRUS == sdata.rav){
syslog(LOG_PRIORITY, "%s: found virus: %s", sdata.ttmpfile, virusinfo);
counters.c_virus++;
inj = OK;
} else if(strlen(sdata.bodydigest) < 10) {
syslog(LOG_PRIORITY, "%s: invalid digest", sdata.ttmpfile);
inj = ERR;
} else {
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: processing message", sdata.ttmpfile);
/* check message against archiving rules */
arule = check_againt_ruleset(data->archiving_rules, &sstate, sdata.tot_len, sdata.spam_message);
if(arule){
syslog(LOG_PRIORITY, "%s: discarding: archiving policy: *%s*", sdata.ttmpfile, arule);
inj = OK;
counters.c_ignore++;
remove_stripped_attachments(&sstate);
}
else {
inj = process_message(&sdata, &sstate, data, cfg);
counters.c_size += sdata.tot_len;
}
}
}
/* set the accept buffer */
snprintf(sdata.acceptbuf, SMALLBUFSIZE-1, "250 Ok %s <%s>\r\n", sdata.ttmpfile, rcpttoemail);
if(inj == ERR) snprintf(sdata.acceptbuf, SMALLBUFSIZE-1, "451 %s <%s>\r\n", sdata.ttmpfile, rcpttoemail);
write1(new_sd, sdata.acceptbuf, strlen(sdata.acceptbuf), sdata.tls, data->ssl);
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: sent: %s", sdata.ttmpfile, sdata.acceptbuf);
counters.c_rcvd++;
if(inj == ERR_EXISTS){
syslog(LOG_PRIORITY, "%s: discarding: duplicate message", sdata.ttmpfile);
counters.c_duplicate++;
}
snprintf(delay, SMALLBUFSIZE-1, "delay=%.2f, delays=%.2f/%.2f/%.2f/%.2f/%.2f/%.2f",
(sdata.__acquire+sdata.__parsed+sdata.__av+sdata.__compress+sdata.__encrypt+sdata.__store)/1000000.0,
sdata.__acquire/1000000.0, sdata.__parsed/1000000.0, sdata.__av/1000000.0, sdata.__compress/1000000.0, sdata.__encrypt/1000000.0, sdata.__store/1000000.0);
syslog(LOG_PRIORITY, "%s: from=%s, size=%d, attachments=%d, reference=%s, message-id=%s, retention=%d, %s", sdata.ttmpfile, sdata.fromemail, sdata.tot_len, sstate.n_attachments, sstate.reference, sstate.message_id, sstate.retention, delay);
#ifdef HAVE_LMTP
} /* for */
#endif
END_OF_PROCESSING:
unlink(sdata.ttmpfile);
unlink(sdata.tmpframe);
/* if we have nothing after the trailing (.), we can read
the next command from the network */
if(puf[n-3] == '.' && puf[n-2] == '\r' && puf[n-1] == '\n') continue;
/* if we left something in the puffer, we are ready to proceed
to handle the additional commands, such as QUIT */
/* if we miss the trailing \r\n, ie. we need another read */
if(puf[n-2] != '\r' && puf[n-1] != '\n'){
memmove(puf, puf+pos, n-pos);
memset(puf+n-pos, 0, MAXBUFSIZE-n+pos);
i = recvtimeout(new_sd, buf, MAXBUFSIZE, TIMEOUT);
strncat(puf, buf, MAXBUFSIZE-1-n+pos);
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: partial read: %s", sdata.ttmpfile, puf);
pos = 0;
}
} /* PERIOD found */
else {
ret = write(sdata.fd, puf, n);
sdata.tot_len += ret;
memcpy(prevbuf, puf, n);
prevlen = n;
continue;
}
} /* SMTP DATA */
AFTER_PERIOD:
/* handle smtp commands */
memset(resp, 0, MAXBUFSIZE);
p = &puf[pos];
while((p = split_str(p, "\r\n", buf, MAXBUFSIZE-1))){
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: got: %s", sdata.ttmpfile, buf);
if(strncasecmp(buf, SMTP_CMD_EHLO, strlen(SMTP_CMD_EHLO)) == 0 || strncasecmp(buf, LMTP_CMD_LHLO, strlen(LMTP_CMD_LHLO)) == 0){
if(state == SMTP_STATE_INIT) state = SMTP_STATE_HELO;
if(sdata.tls == 0) snprintf(buf, MAXBUFSIZE-1, SMTP_RESP_250_EXTENSIONS, cfg->hostid, data->starttls);
else snprintf(buf, MAXBUFSIZE-1, SMTP_RESP_250_EXTENSIONS, cfg->hostid, "");
strncat(resp, buf, MAXBUFSIZE-1);
continue;
/* FIXME: implement the ENHANCEDSTATUSCODE extensions */
}
if(strncasecmp(buf, SMTP_CMD_HELO, strlen(SMTP_CMD_HELO)) == 0){
if(state == SMTP_STATE_INIT) state = SMTP_STATE_HELO;
strncat(resp, SMTP_RESP_250_OK, MAXBUFSIZE-1);
continue;
}
#ifdef HAVE_STARTTLS
if(cfg->tls_enable > 0 && strncasecmp(buf, SMTP_CMD_STARTTLS, strlen(SMTP_CMD_STARTTLS)) == 0 && strlen(data->starttls) > 4 && sdata.tls == 0){
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: starttls request from client", sdata.ttmpfile);
if(data->ctx){
data->ssl = SSL_new(data->ctx);
if(data->ssl){
if(SSL_set_fd(data->ssl, new_sd) == 1){
strncat(resp, SMTP_RESP_220_READY_TO_START_TLS, MAXBUFSIZE-1);
starttls = 1;
state = SMTP_STATE_INIT;
continue;
} syslog(LOG_PRIORITY, "%s: SSL_set_fd() failed", sdata.ttmpfile);
} syslog(LOG_PRIORITY, "%s: SSL_new() failed", sdata.ttmpfile);
} syslog(LOG_PRIORITY, "%s: SSL ctx is null!", sdata.ttmpfile);
strncat(resp, SMTP_RESP_454_ERR_TLS_TEMP_ERROR, MAXBUFSIZE-1);
continue;
}
#endif
if(strncasecmp(buf, SMTP_CMD_MAIL_FROM, strlen(SMTP_CMD_MAIL_FROM)) == 0){
if(state != SMTP_STATE_HELO && state != SMTP_STATE_PERIOD){
strncat(resp, SMTP_RESP_503_ERR, MAXBUFSIZE-1);
}
else {
if(state == SMTP_STATE_PERIOD){
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: initiated new transaction", sdata.ttmpfile);
unlink(sdata.ttmpfile);
unlink(sdata.tmpframe);
init_session_data(&sdata, cfg);
}
state = SMTP_STATE_MAIL_FROM;
snprintf(sdata.mailfrom, SMALLBUFSIZE-1, "%s\r\n", buf);
memset(sdata.fromemail, 0, SMALLBUFSIZE);
extractEmail(sdata.mailfrom, sdata.fromemail);
strncat(resp, SMTP_RESP_250_OK, strlen(SMTP_RESP_250_OK));
}
continue;
}
if(strncasecmp(buf, SMTP_CMD_RCPT_TO, strlen(SMTP_CMD_RCPT_TO)) == 0){
if(state == SMTP_STATE_MAIL_FROM || state == SMTP_STATE_RCPT_TO){
if(strlen(buf) > SMALLBUFSIZE/2){
strncat(resp, SMTP_RESP_550_ERR_TOO_LONG_RCPT_TO, MAXBUFSIZE-1);
continue;
}
if(sdata.num_of_rcpt_to < MAX_RCPT_TO-1){
snprintf(sdata.rcptto[sdata.num_of_rcpt_to], SMALLBUFSIZE-1, "%s\r\n", buf);
}
state = SMTP_STATE_RCPT_TO;
/* check against blackhole addresses */
extractEmail(buf, rcpttoemail);
#ifdef HAVE_MULTITENANCY
if(sdata.customer_id == 0) sdata.customer_id = get_customer_id_by_rcpt_to_email(rcpttoemail, data);
#endif
if(sdata.num_of_rcpt_to < MAX_RCPT_TO-1) sdata.num_of_rcpt_to++;
strncat(resp, SMTP_RESP_250_OK, MAXBUFSIZE-1);
}
else {
strncat(resp, SMTP_RESP_503_ERR, MAXBUFSIZE-1);
}
continue;
}
if(strncasecmp(buf, SMTP_CMD_DATA, strlen(SMTP_CMD_DATA)) == 0){
memset(last2buf, 0, 2*MAXBUFSIZE+1);
memset(prevbuf, 0, MAXBUFSIZE);
inj = ERR;
prevlen = 0;
if(state != SMTP_STATE_RCPT_TO){
strncat(resp, SMTP_RESP_503_ERR, MAXBUFSIZE-1);
}
else {
sdata.fd = open(sdata.filename, O_CREAT|O_RDWR, S_IRUSR|S_IWUSR|S_IRGRP);
if(sdata.fd == -1){
syslog(LOG_PRIORITY, "%s: %s", ERR_OPEN_TMP_FILE, sdata.ttmpfile);
strncat(resp, SMTP_RESP_451_ERR, MAXBUFSIZE-1);
}
else {
state = SMTP_STATE_DATA;
strncat(resp, SMTP_RESP_354_DATA_OK, MAXBUFSIZE-1);
}
}
continue;
}
if(strncasecmp(buf, SMTP_CMD_QUIT, strlen(SMTP_CMD_QUIT)) == 0){
state = SMTP_STATE_FINISHED;
snprintf(buf, MAXBUFSIZE-1, SMTP_RESP_221_GOODBYE, cfg->hostid);
strncat(resp, buf, MAXBUFSIZE-1);
unlink(sdata.ttmpfile);
unlink(sdata.tmpframe);
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: removed", sdata.ttmpfile);
continue;
}
if(strncasecmp(buf, SMTP_CMD_NOOP, strlen(SMTP_CMD_NOOP)) == 0){
strncat(resp, SMTP_RESP_250_OK, MAXBUFSIZE-1);
continue;
}
if(strncasecmp(buf, SMTP_CMD_RESET, strlen(SMTP_CMD_RESET)) == 0){
strncat(resp, SMTP_RESP_250_OK, MAXBUFSIZE-1);
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: removed", sdata.ttmpfile);
unlink(sdata.ttmpfile);
unlink(sdata.tmpframe);
init_session_data(&sdata, cfg);
state = SMTP_STATE_HELO;
continue;
}
/* by default send 502 command not implemented message */
syslog(LOG_PRIORITY, "%s: invalid command: *%s*", sdata.ttmpfile, buf);
strncat(resp, SMTP_RESP_502_ERR, MAXBUFSIZE-1);
}
/* now we can send our buffered response */
if(strlen(resp) > 0){
write1(new_sd, resp, strlen(resp), sdata.tls, data->ssl);
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: sent: %s", sdata.ttmpfile, resp);
memset(resp, 0, MAXBUFSIZE);
#ifdef HAVE_STARTTLS
if(starttls == 1 && sdata.tls == 0){
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: waiting for ssl handshake", sdata.ttmpfile);
rc = SSL_accept(data->ssl);
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: SSL_accept() finished", sdata.ttmpfile);
if(rc == 1){
sdata.tls = 1;
}
else {
ERR_error_string_n(ERR_get_error(), ssl_error, SMALLBUFSIZE);
syslog(LOG_PRIORITY, "%s: SSL_accept() failed, rc=%d, errorcode: %d, error text: %s\n", sdata.ttmpfile, rc, SSL_get_error(data->ssl, rc), ssl_error);
}
}
#endif
}
if(state == SMTP_STATE_FINISHED){
goto QUITTING;
}
} /* while */
/*
* if we are not in SMTP_STATE_QUIT and the message was not injected,
* ie. we have timed out than send back 421 error message
*/
if(state < SMTP_STATE_QUIT && inj == ERR){
snprintf(buf, MAXBUFSIZE-1, SMTP_RESP_421_ERR, cfg->hostid);
write1(new_sd, buf, strlen(buf), sdata.tls, data->ssl);
if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: sent: %s", sdata.ttmpfile, buf);
if(sdata.fd != -1){
syslog(LOG_PRIORITY, "%s: removing stale files: %s, %s", sdata.ttmpfile, sdata.ttmpfile, sdata.tmpframe);
close(sdata.fd);
unlink(sdata.ttmpfile);
unlink(sdata.tmpframe);
}
goto QUITTING;
}
QUITTING:
update_counters(&sdata, data, &counters, cfg);
#ifdef NEED_MYSQL
close_database(&sdata);
#endif
#ifdef HAVE_STARTTLS
if(sdata.tls == 1){
SSL_shutdown(data->ssl);
SSL_free(data->ssl);
}
#endif
if(cfg->verbosity >= _LOG_INFO) syslog(LOG_PRIORITY, "processed %llu messages", counters.c_rcvd);
return (int)counters.c_rcvd;
}