int pass_trigger(const char *service, const char *buf, ssize_t len, int timeout)
{
const char *myname = "pass_trigger";
int pass_fd[2];
struct pass_trigger *pp;
int connect_fd;
if (msg_verbose > 1)
msg_info("%s: service %s", myname, service);
/*
* Connect...
*/
if ((connect_fd = LOCAL_CONNECT(service, BLOCKING, timeout)) < 0) {
if (msg_verbose)
msg_warn("%s: connect to %s: %m", myname, service);
return (-1);
}
close_on_exec(connect_fd, CLOSE_ON_EXEC);
/*
* Create a pipe, and send one pipe end to the server.
*/
if (pipe(pass_fd) < 0)
msg_fatal("%s: pipe: %m", myname);
close_on_exec(pass_fd[0], CLOSE_ON_EXEC);
close_on_exec(pass_fd[1], CLOSE_ON_EXEC);
if (LOCAL_SEND_FD(connect_fd, pass_fd[0]) < 0)
msg_fatal("%s: send file descriptor: %m", myname);
/*
* Stash away context.
*/
pp = (struct pass_trigger *) mymalloc(sizeof(*pp));
pp->connect_fd = connect_fd;
pp->service = mystrdup(service);
pp->pass_fd[0] = pass_fd[0];
pp->pass_fd[1] = pass_fd[1];
/*
* Write the request...
*/
if (write_buf(pass_fd[1], buf, len, timeout) < 0
|| write_buf(pass_fd[1], "", 1, timeout) < 0)
if (msg_verbose)
msg_warn("%s: write to %s: %m", myname, service);
/*
* Wakeup when the peer disconnects, or when we lose patience.
*/
if (timeout > 0)
event_request_timer(pass_trigger_event, (char *) pp, timeout + 100);
event_enable_read(connect_fd, pass_trigger_event, (char *) pp);
return (0);
}
VSTREAM *tls_proxy_open(const char *service, int flags,
VSTREAM *peer_stream,
const char *peer_addr,
const char *peer_port,
int timeout)
{
VSTREAM *tlsproxy_stream;
int status;
int fd;
static VSTRING *tlsproxy_service = 0;
static VSTRING *remote_endpt = 0;
/*
* Initialize.
*/
if (tlsproxy_service == 0) {
tlsproxy_service = vstring_alloc(20);
remote_endpt = vstring_alloc(20);
}
/*
* Connect to the tlsproxy(8) daemon.
*/
vstring_sprintf(tlsproxy_service, "%s/%s", MAIL_CLASS_PRIVATE, service);
if ((fd = LOCAL_CONNECT(STR(tlsproxy_service), BLOCKING,
TLSPROXY_INIT_TIMEOUT)) < 0) {
msg_warn("connect to %s service: %m", STR(tlsproxy_service));
return (0);
}
/*
* Initial handshake. Send the data attributes now, and send the client
* file descriptor in a later transaction.
*
* XXX The formatted endpoint should be a state member. Then, we can
* simplify all the format strings throughout the program.
*/
tlsproxy_stream = vstream_fdopen(fd, O_RDWR);
vstring_sprintf(remote_endpt, "[%s]:%s", peer_addr, peer_port);
attr_print(tlsproxy_stream, ATTR_FLAG_NONE,
ATTR_TYPE_STR, MAIL_ATTR_REMOTE_ENDPT, STR(remote_endpt),
ATTR_TYPE_INT, MAIL_ATTR_FLAGS, flags,
ATTR_TYPE_INT, MAIL_ATTR_TIMEOUT, timeout,
ATTR_TYPE_END);
if (vstream_fflush(tlsproxy_stream) != 0) {
msg_warn("error sending request to %s service: %m",
STR(tlsproxy_service));
vstream_fclose(tlsproxy_stream);
return (0);
}
/*
* Receive the "TLS is available" indication.
*
* This may seem out of order, but we must have a read transaction between
* sending the request attributes and sending the SMTP client file
* descriptor. We can't assume UNIX-domain socket semantics here.
*/
if (attr_scan(tlsproxy_stream, ATTR_FLAG_STRICT,
ATTR_TYPE_INT, MAIL_ATTR_STATUS, &status,
ATTR_TYPE_END) != 1 || status == 0) {
/*
* The TLS proxy reports that the TLS engine is not available (due to
* configuration error, or other causes).
*/
msg_warn("%s service role \"%s\" is not available",
STR(tlsproxy_service),
(flags & TLS_PROXY_FLAG_ROLE_SERVER) ? "server" :
(flags & TLS_PROXY_FLAG_ROLE_CLIENT) ? "client" :
"bogus role");
vstream_fclose(tlsproxy_stream);
return (0);
}
/*
* Send the remote SMTP client file descriptor.
*/
if (LOCAL_SEND_FD(vstream_fileno(tlsproxy_stream),
vstream_fileno(peer_stream)) < 0) {
/*
* Some error: drop the TLS proxy stream.
*/
msg_warn("sending file handle to %s service: %m",
STR(tlsproxy_service));
vstream_fclose(tlsproxy_stream);
return (0);
}
return (tlsproxy_stream);
}
int psc_dnsbl_request(const char *client_addr,
void (*callback) (int, void *),
void *context)
{
const char *myname = "psc_dnsbl_request";
int fd;
VSTREAM *stream;
HTABLE_INFO **ht;
PSC_DNSBL_SCORE *score;
HTABLE_INFO *hash_node;
static int request_count;
/*
* Some spambots make several connections at nearly the same time,
* causing their pregreet delays to overlap. Such connections can share
* the efforts of DNSBL lookup.
*
* We store a reference-counted DNSBL score under its client IP address. We
* increment the reference count with each score request, and decrement
* the reference count with each score retrieval.
*
* Do not notify the requestor NOW when the DNS replies are already in.
* Reason: we must not make a backwards call while we are still in the
* middle of executing the corresponding forward call. Instead we create
* a zero-delay timer request and call the notification function from
* there.
*
* psc_dnsbl_request() could instead return a result value to indicate that
* the DNSBL score is already available, but that would complicate the
* caller with two different notification code paths: one asynchronous
* code path via the callback invocation, and one synchronous code path
* via the psc_dnsbl_request() result value. That would be a source of
* future bugs.
*/
if ((hash_node = htable_locate(dnsbl_score_cache, client_addr)) != 0) {
score = (PSC_DNSBL_SCORE *) hash_node->value;
score->refcount += 1;
PSC_CALL_BACK_EXTEND(hash_node, score);
PSC_CALL_BACK_ENTER(score, callback, context);
if (msg_verbose > 1)
msg_info("%s: reuse blocklist score for %s refcount=%d pending=%d",
myname, client_addr, score->refcount,
score->pending_lookups);
if (score->pending_lookups == 0)
event_request_timer(callback, context, EVENT_NULL_DELAY);
return (PSC_CALL_BACK_INDEX_OF_LAST(score));
}
if (msg_verbose > 1)
msg_info("%s: create blocklist score for %s", myname, client_addr);
score = (PSC_DNSBL_SCORE *) mymalloc(sizeof(*score));
score->request_id = request_count++;
score->dnsbl_name = 0;
score->dnsbl_weight = 0;
/* As with dnsblog(8), a value < 0 means no reply TTL. */
score->pass_ttl = -1;
score->fail_ttl = -1;
score->total = 0;
score->refcount = 1;
score->pending_lookups = 0;
PSC_CALL_BACK_INIT(score);
PSC_CALL_BACK_ENTER(score, callback, context);
(void) htable_enter(dnsbl_score_cache, client_addr, (void *) score);
/*
* Send a query to all DNSBL servers. Later, DNSBL lookup will be done
* with an UDP-based DNS client that is built directly into Postfix code.
* We therefore do not optimize the maximum out of this temporary
* implementation.
*/
for (ht = dnsbl_site_list; *ht; ht++) {
if ((fd = LOCAL_CONNECT(psc_dnsbl_service, NON_BLOCKING, 1)) < 0) {
msg_warn("%s: connect to %s service: %m",
myname, psc_dnsbl_service);
continue;
}
stream = vstream_fdopen(fd, O_RDWR);
vstream_control(stream,
CA_VSTREAM_CTL_CONTEXT(ht[0]->key),
CA_VSTREAM_CTL_END);
attr_print(stream, ATTR_FLAG_NONE,
SEND_ATTR_STR(MAIL_ATTR_RBL_DOMAIN, ht[0]->key),
SEND_ATTR_STR(MAIL_ATTR_ACT_CLIENT_ADDR, client_addr),
SEND_ATTR_INT(MAIL_ATTR_LABEL, score->request_id),
ATTR_TYPE_END);
if (vstream_fflush(stream) != 0) {
msg_warn("%s: error sending to %s service: %m",
myname, psc_dnsbl_service);
vstream_fclose(stream);
continue;
}
PSC_READ_EVENT_REQUEST(vstream_fileno(stream), psc_dnsbl_receive,
(void *) stream, var_psc_dnsbl_tmout);
score->pending_lookups += 1;
}
return (PSC_CALL_BACK_INDEX_OF_LAST(score));
}
void psc_send_socket(PSC_STATE *state)
{
const char *myname = "psc_send_socket";
int server_fd;
int pass_err;
VSTREAM *fp;
if (msg_verbose > 1)
msg_info("%s: sq=%d cq=%d send socket %d from [%s]:%s",
myname, psc_post_queue_length, psc_check_queue_length,
vstream_fileno(state->smtp_client_stream),
state->smtp_client_addr, state->smtp_client_port);
/*
* Connect to the real SMTP service over a local IPC channel, send the
* file descriptor, and close the file descriptor to save resources.
* Experience has shown that some systems will discard information when
* we close a channel immediately after writing. Thus, we waste resources
* waiting for the remote side to close the local IPC channel first. The
* good side of waiting is that we learn when the real SMTP server is
* falling behind.
*
* This is where we would forward the connection to an SMTP server that
* provides an appropriate level of service for this client class. For
* example, a server that is more forgiving, or one that is more
* suspicious. Alternatively, we could send attributes along with the
* socket with client reputation information, making everything even more
* Postfix-specific.
*/
if ((server_fd =
LOCAL_CONNECT(psc_smtpd_service_name, NON_BLOCKING,
PSC_SEND_SOCK_CONNECT_TIMEOUT)) < 0) {
msg_warn("cannot connect to service %s: %m", psc_smtpd_service_name);
if (state->flags & PSC_STATE_FLAG_PREGR_TODO) {
PSC_SMTPD_X21(state, "421 4.3.2 No system resources\r\n");
} else {
PSC_SEND_REPLY(state, "421 4.3.2 All server ports are busy\r\n");
psc_free_session_state(state);
}
return;
}
/* XXX Note: no dummy read between LOCAL_SEND_FD() and attr_print(). */
fp = vstream_fdopen(server_fd, O_RDWR);
pass_err =
(LOCAL_SEND_FD(server_fd,
vstream_fileno(state->smtp_client_stream)) < 0
|| (attr_print(fp, ATTR_FLAG_NONE,
SEND_ATTR_STR(MAIL_ATTR_ACT_CLIENT_ADDR, state->smtp_client_addr),
SEND_ATTR_STR(MAIL_ATTR_ACT_CLIENT_PORT, state->smtp_client_port),
SEND_ATTR_STR(MAIL_ATTR_ACT_SERVER_ADDR, state->smtp_server_addr),
SEND_ATTR_STR(MAIL_ATTR_ACT_SERVER_PORT, state->smtp_server_port),
ATTR_TYPE_END) || vstream_fflush(fp)));
/* XXX Note: no read between attr_print() and vstream_fdclose(). */
(void) vstream_fdclose(fp);
if (pass_err != 0) {
msg_warn("cannot pass connection to service %s: %m",
psc_smtpd_service_name);
(void) close(server_fd);
if (state->flags & PSC_STATE_FLAG_PREGR_TODO) {
PSC_SMTPD_X21(state, "421 4.3.2 No system resources\r\n");
} else {
PSC_SEND_REPLY(state, "421 4.3.2 No system resources\r\n");
psc_free_session_state(state);
}
return;
} else {
/*
* Closing the smtp_client_fd here triggers a FreeBSD 7.1 kernel bug
* where smtp-source sometimes sees the connection being closed after
* it has already received the real SMTP server's 220 greeting!
*/
#if 0
PSC_DEL_CLIENT_STATE(state);
#endif
PSC_ADD_SERVER_STATE(state, server_fd);
PSC_READ_EVENT_REQUEST(state->smtp_server_fd, psc_send_socket_close_event,
(void *) state, PSC_SEND_SOCK_NOTIFY_TIMEOUT);
return;
}
}