* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2016 */
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim Maintainers 2020 */
/* See the file NOTICE for conditions of use and distribution. */
/* A number of functions for driving outgoing SMTP calls. */
if (!(expint = expand_string(istring)))
{
- if (expand_string_forcedfail) return TRUE;
+ if (f.expand_string_forcedfail) return TRUE;
addr->transport_return = PANIC;
addr->message = string_sprintf("failed to expand \"interface\" "
"option for %s: %s", msg, expand_string_message);
return FALSE;
}
-while (isspace(*expint)) expint++;
-if (*expint == 0) return TRUE;
+if (is_tainted(expint))
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC,
+ "attempt to use tainted value '%s' from '%s' for interface",
+ expint, istring);
+ addr->transport_return = PANIC;
+ addr->message = string_sprintf("failed to expand \"interface\" "
+ "option for %s: configuration error", msg);
+ return FALSE;
+ }
+
+Uskip_whitespace(&expint);
+if (!*expint) return TRUE;
while ((iface = string_nextinlist(&expint, &sep, big_buffer,
big_buffer_size)))
{
uschar *pstring = expand_string(rstring);
-if (pstring == NULL)
+if (!pstring)
{
addr->transport_return = PANIC;
addr->message = string_sprintf("failed to expand \"%s\" (\"port\" option) "
else
{
struct servent *smtp_service = getservbyname(CS pstring, "tcp");
- if (smtp_service == NULL)
+ if (!smtp_service)
{
addr->transport_return = PANIC;
addr->message = string_sprintf("TCP port \"%s\" is not defined for %s",
+#ifdef TCP_FASTOPEN
+static void
+tfo_out_check(int sock)
+{
+# ifdef __FreeBSD__
+struct tcp_info tinfo;
+int val;
+socklen_t len = sizeof(val);
+
+/* The observability as of 12.1 is not useful as a client, only telling us that
+a TFO option was used on SYN. It could have been a TFO-R, or ignored by the
+server. */
+
+/*
+if (tcp_out_fastopen == TFO_ATTEMPTED_NODATA || tcp_out_fastopen == TFO_ATTEMPTED_DATA)
+ if (getsockopt(sock, IPPROTO_TCP, TCP_FASTOPEN, &val, &len) == 0 && val != 0) {}
+*/
+switch (tcp_out_fastopen)
+ {
+ case TFO_ATTEMPTED_NODATA: tcp_out_fastopen = TFO_USED_NODATA; break;
+ case TFO_ATTEMPTED_DATA: tcp_out_fastopen = TFO_USED_DATA; break;
+ default: break; /* compiler quietening */
+ }
+
+# else /* Linux & Apple */
+# if defined(TCP_INFO) && defined(EXIM_HAVE_TCPI_UNACKED)
+struct tcp_info tinfo;
+socklen_t len = sizeof(tinfo);
+
+switch (tcp_out_fastopen)
+ {
+ /* This is a somewhat dubious detection method; totally undocumented so likely
+ to fail in future kernels. There seems to be no documented way. What we really
+ want to know is if the server sent smtp-banner data before our ACK of his SYN,ACK
+ hit him. What this (possibly?) detects is whether we sent a TFO cookie with our
+ SYN, as distinct from a TFO request. This gets a false-positive when the server
+ key is rotated; we send the old one (which this test sees) but the server returns
+ the new one and does not send its SMTP banner before we ACK his SYN,ACK.
+ To force that rotation case:
+ '# echo -n "00000000-00000000-00000000-0000000" >/proc/sys/net/ipv4/tcp_fastopen_key'
+ The kernel seems to be counting unack'd packets. */
+
+ case TFO_ATTEMPTED_NODATA:
+ if ( getsockopt(sock, IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
+ && tinfo.tcpi_state == TCP_SYN_SENT
+ && tinfo.tcpi_unacked > 1
+ )
+ {
+ DEBUG(D_transport|D_v)
+ debug_printf("TCP_FASTOPEN tcpi_unacked %d\n", tinfo.tcpi_unacked);
+ tcp_out_fastopen = TFO_USED_NODATA;
+ }
+ break;
+
+ /* When called after waiting for received data we should be able
+ to tell if data we sent was accepted. */
+
+ case TFO_ATTEMPTED_DATA:
+ if ( getsockopt(sock, IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
+ && tinfo.tcpi_state == TCP_ESTABLISHED
+ )
+ if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA)
+ {
+ DEBUG(D_transport|D_v) debug_printf("TFO: data was acked\n");
+ tcp_out_fastopen = TFO_USED_DATA;
+ }
+ else
+ {
+ DEBUG(D_transport|D_v) debug_printf("TFO: had to retransmit\n");
+ tcp_out_fastopen = TFO_NOT_USED;
+ }
+ break;
+
+ default: break; /* compiler quietening */
+ }
+# endif
+# endif /* Linux & Apple */
+}
+#endif
+
+
+/* Arguments as for smtp_connect(), plus
+ early_data if non-NULL, idenmpotent data to be sent -
+ preferably in the TCP SYN segment
+
+Returns: connected socket number, or -1 with errno set
+*/
+
int
smtp_sock_connect(host_item * host, int host_af, int port, uschar * interface,
- transport_instance * tb, int timeout)
+ transport_instance * tb, int timeout, const blob * early_data)
{
smtp_transport_options_block * ob =
(smtp_transport_options_block *)tb->options_block;
int dscp_option;
int sock;
int save_errno = 0;
-BOOL fastopen = FALSE;
+const blob * fastopen_blob = NULL;
+
#ifndef DISABLE_EVENT
deliver_host_address = host->address;
if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
HDEBUG(D_transport|D_acl|D_v)
- debug_printf("failed to set NODELAY: %s ", strerror(errno));
+ debug_printf_indent("failed to set NODELAY: %s ", strerror(errno));
/* Set DSCP value, if we can. For now, if we fail to set the value, we don't
bomb out, just log it and continue in default traffic class. */
if (dscp && dscp_lookup(dscp, host_af, &dscp_level, &dscp_option, &dscp_value))
{
HDEBUG(D_transport|D_acl|D_v)
- debug_printf("DSCP \"%s\"=%x ", dscp, dscp_value);
+ debug_printf_indent("DSCP \"%s\"=%x ", dscp, dscp_value);
if (setsockopt(sock, dscp_level, dscp_option, &dscp_value, sizeof(dscp_value)) < 0)
HDEBUG(D_transport|D_acl|D_v)
- debug_printf("failed to set DSCP: %s ", strerror(errno));
+ debug_printf_indent("failed to set DSCP: %s ", strerror(errno));
/* If the kernel supports IPv4 and IPv6 on an IPv6 socket, we need to set the
option for both; ignore failures here */
if (host_af == AF_INET6 &&
(void) setsockopt(sock, dscp_level, dscp_option, &dscp_value, sizeof(dscp_value));
}
-#ifdef TCP_FASTOPEN
-if (verify_check_given_host (&ob->hosts_try_fastopen, host) == OK) fastopen = TRUE;
-#endif
-
/* Bind to a specific interface if requested. Caller must ensure the interface
is the same type (IPv4 or IPv6) as the outgoing address. */
{
save_errno = errno;
HDEBUG(D_transport|D_acl|D_v)
- debug_printf("unable to bind outgoing SMTP call to %s: %s", interface,
+ debug_printf_indent("unable to bind outgoing SMTP call to %s: %s", interface,
strerror(errno));
}
/* Connect to the remote host, and add keepalive to the socket before returning
-it, if requested. */
+it, if requested. If the build supports TFO, request it - and if the caller
+requested some early-data then include that in the TFO request. If there is
+early-data but no TFO support, send it after connecting. */
-else if (ip_connect(sock, host_af, host->address, port, timeout, fastopen) < 0)
- save_errno = errno;
+else
+ {
+#ifdef TCP_FASTOPEN
+ if (verify_check_given_host(CUSS &ob->hosts_try_fastopen, host) == OK)
+ fastopen_blob = early_data ? early_data : &tcp_fastopen_nodata;
+#endif
+
+ if (ip_connect(sock, host_af, host->address, port, timeout, fastopen_blob) < 0)
+ save_errno = errno;
+ else if (early_data && !fastopen_blob && early_data->data && early_data->len)
+ {
+ HDEBUG(D_transport|D_acl|D_v)
+ debug_printf("sending %ld nonTFO early-data\n", (long)early_data->len);
+
+#ifdef TCP_QUICKACK
+ (void) setsockopt(sock, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
+#endif
+ if (send(sock, early_data->data, early_data->len, 0) < 0)
+ save_errno = errno;
+ }
+ }
/* Either bind() or connect() failed */
{
HDEBUG(D_transport|D_acl|D_v)
{
- debug_printf("failed: %s", CUstrerror(save_errno));
+ debug_printf_indent(" failed: %s", CUstrerror(save_errno));
if (save_errno == ETIMEDOUT)
debug_printf(" (timeout=%s)", readconf_printtime(timeout));
debug_printf("\n");
return -1;
}
-/* Both bind() and connect() succeeded */
+/* Both bind() and connect() succeeded, and any early-data */
else
{
union sockaddr_46 interface_sock;
EXIM_SOCKLEN_T size = sizeof(interface_sock);
- HDEBUG(D_transport|D_acl|D_v) debug_printf("connected\n");
+
+ HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" connected\n");
if (getsockname(sock, (struct sockaddr *)(&interface_sock), &size) == 0)
sending_ip_address = host_ntoa(-1, &interface_sock, NULL, &sending_port);
else
close(sock);
return -1;
}
+
if (ob->keepalive) ip_keepalive(sock, host->address, TRUE);
+#ifdef TCP_FASTOPEN
+ tfo_out_check(sock);
+#endif
return sock;
}
}
+
+
+
+
+void
+smtp_port_for_connect(host_item * host, int port)
+{
+if (host->port != PORT_NONE)
+ {
+ HDEBUG(D_transport|D_acl|D_v) if (port != host->port)
+ debug_printf_indent("Transport port=%d replaced by host-specific port=%d\n", port,
+ host->port);
+ port = host->port;
+ }
+else host->port = port; /* Set the port actually used */
+}
+
+
/*************************************************
* Connect to remote host *
*************************************************/
non-IPv6 systems, to enable the code to be less messy. However, on such systems
host->address will always be an IPv4 address.
-The port field in the host item is used if it is set (usually router from SRV
-records or elsewhere). In other cases, the default passed as an argument is
-used, and the host item is updated with its value.
-
Arguments:
- host host item containing name and address (and sometimes port)
- host_af AF_INET or AF_INET6
- port default remote port to connect to, in host byte order, for those
- hosts whose port setting is PORT_NONE
- interface outgoing interface address or NULL
- timeout timeout value or 0
- tb transport
+ sc details for making connection: host, af, interface, transport
+ early_data if non-NULL, data to be sent - preferably in the TCP SYN segment
Returns: connected socket number, or -1 with errno set
*/
int
-smtp_connect(host_item *host, int host_af, int port, uschar *interface,
- int timeout, transport_instance * tb)
+smtp_connect(smtp_connect_args * sc, const blob * early_data)
{
-#ifdef SUPPORT_SOCKS
-smtp_transport_options_block * ob =
- (smtp_transport_options_block *)tb->options_block;
-#endif
-
-if (host->port != PORT_NONE)
- {
- HDEBUG(D_transport|D_acl|D_v)
- debug_printf("Transport port=%d replaced by host-specific port=%d\n", port,
- host->port);
- port = host->port;
- }
-else host->port = port; /* Set the port actually used */
+int port = sc->host->port;
+smtp_transport_options_block * ob = sc->ob;
-callout_address = string_sprintf("[%s]:%d", host->address, port);
+callout_address = string_sprintf("[%s]:%d", sc->host->address, port);
HDEBUG(D_transport|D_acl|D_v)
{
uschar * s = US" ";
- if (interface) s = string_sprintf(" from %s ", interface);
+ if (sc->interface) s = string_sprintf(" from %s ", sc->interface);
#ifdef SUPPORT_SOCKS
if (ob->socks_proxy) s = string_sprintf("%svia proxy ", s);
#endif
- debug_printf("Connecting to %s %s%s... ", host->name, callout_address, s);
+ debug_printf_indent("Connecting to %s %s%s... ", sc->host->name, callout_address, s);
}
/* Create and connect the socket */
#ifdef SUPPORT_SOCKS
if (ob->socks_proxy)
- return socks_sock_connect(host, host_af, port, interface, tb, timeout);
+ {
+ int sock = socks_sock_connect(sc->host, sc->host_af, port, sc->interface,
+ sc->tblock, ob->connect_timeout);
+
+ if (sock >= 0)
+ {
+ if (early_data && early_data->data && early_data->len)
+ if (send(sock, early_data->data, early_data->len, 0) < 0)
+ {
+ int save_errno = errno;
+ HDEBUG(D_transport|D_acl|D_v)
+ {
+ debug_printf_indent("failed: %s", CUstrerror(save_errno));
+ if (save_errno == ETIMEDOUT)
+ debug_printf(" (timeout=%s)", readconf_printtime(ob->connect_timeout));
+ debug_printf("\n");
+ }
+ (void)close(sock);
+ sock = -1;
+ errno = save_errno;
+ }
+ }
+ return sock;
+ }
#endif
-return smtp_sock_connect(host, host_af, port, interface, tb, timeout);
+return smtp_sock_connect(sc->host, sc->host_af, port, sc->interface,
+ sc->tblock, ob->connect_timeout, early_data);
}
Argument:
outblock the SMTP output block
+ mode further data expected, or plain
Returns: TRUE if OK, FALSE on error, with errno set
*/
static BOOL
-flush_buffer(smtp_outblock *outblock)
+flush_buffer(smtp_outblock * outblock, int mode)
{
int rc;
int n = outblock->ptr - outblock->buffer;
+BOOL more = mode == SCMD_MORE;
-HDEBUG(D_transport|D_acl) debug_printf("cmd buf flush %d bytes\n", n);
-#ifdef SUPPORT_TLS
-if (tls_out.active == outblock->sock)
- rc = tls_write(FALSE, outblock->buffer, n);
+HDEBUG(D_transport|D_acl) debug_printf_indent("cmd buf flush %d bytes%s\n", n,
+ more ? " (more expected)" : "");
+
+#ifndef DISABLE_TLS
+if (outblock->cctx->tls_ctx)
+ rc = tls_write(outblock->cctx->tls_ctx, outblock->buffer, n, more);
else
#endif
- rc = send(outblock->sock, outblock->buffer, n, 0);
+
+ {
+ if (outblock->conn_args)
+ {
+ blob early_data = { .data = outblock->buffer, .len = n };
+
+ /* We ignore the more-flag if we're doing a connect with early-data, which
+ means we won't get BDAT+data. A pity, but wise due to the idempotency
+ requirement: TFO with data can, in rare cases, replay the data to the
+ receiver. */
+
+ if ( (outblock->cctx->sock = smtp_connect(outblock->conn_args, &early_data))
+ < 0)
+ return FALSE;
+ outblock->conn_args = NULL;
+ rc = n;
+ }
+ else
+ {
+ rc = send(outblock->cctx->sock, outblock->buffer, n,
+#ifdef MSG_MORE
+ more ? MSG_MORE : 0
+#else
+ 0
+#endif
+ );
+
+#if defined(__linux__)
+ /* This is a workaround for a current linux kernel bug: as of
+ 5.6.8-200.fc31.x86_64 small (<MSS) writes get delayed by about 200ms,
+ This is despite NODELAY being active.
+ https://bugzilla.redhat.com/show_bug.cgi?id=1803806 */
+
+ if (!more)
+ setsockopt(outblock->cctx->sock, IPPROTO_TCP, TCP_CORK, &off, sizeof(off));
+#endif
+ }
+ }
if (rc <= 0)
{
- HDEBUG(D_transport|D_acl) debug_printf("send failed: %s\n", strerror(errno));
+ HDEBUG(D_transport|D_acl) debug_printf_indent("send failed: %s\n", strerror(errno));
return FALSE;
}
any error message.
Arguments:
- outblock contains buffer for pipelining, and socket
- noflush if TRUE, save the command in the output buffer, for pipelining
+ sx SMTP connection, contains buffer for pipelining, and socket
+ mode buffer, write-with-more-likely, write
format a format, starting with one of
of HELO, MAIL FROM, RCPT TO, DATA, ".", or QUIT.
If NULL, flush pipeline buffer only.
*/
int
-smtp_write_command(smtp_outblock *outblock, BOOL noflush, const char *format, ...)
+smtp_write_command(void * sx, int mode, const char *format, ...)
{
-int count;
+smtp_outblock * outblock = &((smtp_context *)sx)->outblock;
int rc = 0;
-va_list ap;
if (format)
{
+ gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
+ va_list ap;
+
+ /* Use taint-unchecked routines for writing into big_buffer, trusting that
+ we'll never expand the results. Actually, the error-message use - leaving
+ the results in big_buffer for potential later use - is uncomfortably distant.
+ XXX Would be better to assume all smtp commands are short, use normal pool
+ alloc rather than big_buffer, and another global for the data-for-error. */
+
va_start(ap, format);
- if (!string_vformat(big_buffer, big_buffer_size, CS format, ap))
+ if (!string_vformat(&gs, SVFMT_TAINT_NOCHK, CS format, ap))
log_write(0, LOG_MAIN|LOG_PANIC_DIE, "overlong write_command in outgoing "
"SMTP");
va_end(ap);
- count = Ustrlen(big_buffer);
+ string_from_gstring(&gs);
- if (count > outblock->buffersize)
+ if (gs.ptr > outblock->buffersize)
log_write(0, LOG_MAIN|LOG_PANIC_DIE, "overlong write_command in outgoing "
"SMTP");
- if (count > outblock->buffersize - (outblock->ptr - outblock->buffer))
+ if (gs.ptr > outblock->buffersize - (outblock->ptr - outblock->buffer))
{
rc = outblock->cmd_count; /* flush resets */
- if (!flush_buffer(outblock)) return -1;
+ if (!flush_buffer(outblock, SCMD_FLUSH)) return -1;
}
- Ustrncpy(CS outblock->ptr, big_buffer, count);
- outblock->ptr += count;
+ Ustrncpy(outblock->ptr, gs.s, gs.ptr);
+ outblock->ptr += gs.ptr;
outblock->cmd_count++;
- count -= 2;
- big_buffer[count] = 0; /* remove \r\n for error message */
+ gs.ptr -= 2; string_from_gstring(&gs); /* remove \r\n for error message */
/* We want to hide the actual data sent in AUTH transactions from reflections
and logs. While authenticating, a flag is set in the outblock to enable this.
while (!isspace(*p)) p++;
while (isspace(*p)) p++;
}
- while (*p != 0) *p++ = '*';
+ while (*p) *p++ = '*';
}
- HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> %s\n", big_buffer);
+ HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP>> %s\n", big_buffer);
}
-if (!noflush)
+if (mode != SCMD_BUFFER)
{
rc += outblock->cmd_count; /* flush resets */
- if (!flush_buffer(outblock)) return -1;
+ if (!flush_buffer(outblock, mode)) return -1;
}
return rc;
inblock the SMTP input block (contains holding buffer, socket, etc.)
buffer where to put the line
size space available for the line
- timeout the timeout to use when reading a packet
+ timelimit deadline for reading the lime, seconds past epoch
Returns: length of a line that has been put in the buffer
-1 otherwise, with errno set
*/
static int
-read_response_line(smtp_inblock *inblock, uschar *buffer, int size, int timeout)
+read_response_line(smtp_inblock *inblock, uschar *buffer, int size, time_t timelimit)
{
uschar *p = buffer;
uschar *ptr = inblock->ptr;
uschar *ptrend = inblock->ptrend;
-int sock = inblock->sock;
+client_conn_ctx * cctx = inblock->cctx;
/* Loop for reading multiple packets or reading another packet after emptying
a previously-read one. */
/* Need to read a new input packet. */
- rc = ip_recv(sock, inblock->buffer, inblock->buffersize, timeout);
- if (rc <= 0) break;
+ if((rc = ip_recv(cctx, inblock->buffer, inblock->buffersize, timelimit)) <= 0)
+ {
+ DEBUG(D_deliver|D_transport|D_acl|D_v)
+ debug_printf_indent(errno ? " SMTP(%s)<<\n" : " SMTP(closed)<<\n",
+ strerror(errno));
+ break;
+ }
/* Another block of data has been successfully read. Set up the pointers
and let the loop continue. */
ptrend = inblock->ptrend = inblock->buffer + rc;
ptr = inblock->buffer;
- DEBUG(D_transport|D_acl) debug_printf("read response data: size=%d\n", rc);
+ DEBUG(D_transport|D_acl) debug_printf_indent("read response data: size=%d\n", rc);
}
/* Get here if there has been some kind of recv() error; errno is set, but we
the error code will be in errno.
Arguments:
- inblock the SMTP input block (contains holding buffer, socket, etc.)
+ sx the SMTP connection (contains input block with holding buffer,
+ socket, etc.)
buffer where to put the response
size the size of the buffer
okdigit the expected first digit of the response
- timeout the timeout to use
+ timeout the timeout to use, in seconds
Returns: TRUE if a valid, non-error response was received; else FALSE
*/
+/*XXX could move to smtp transport; no other users */
BOOL
-smtp_read_response(smtp_inblock *inblock, uschar *buffer, int size, int okdigit,
+smtp_read_response(void * sx0, uschar * buffer, int size, int okdigit,
int timeout)
{
-uschar *ptr = buffer;
-int count;
+smtp_context * sx = sx0;
+uschar * ptr = buffer;
+int count = 0;
+time_t timelimit = time(NULL) + timeout;
errno = 0; /* Ensure errno starts out zero */
-/* This is a loop to read and concatentate the lines that make up a multi-line
+#ifndef DISABLE_PIPE_CONNECT
+if (sx->pending_BANNER || sx->pending_EHLO)
+ {
+ int rc;
+ if ((rc = smtp_reap_early_pipe(sx, &count)) != OK)
+ {
+ DEBUG(D_transport) debug_printf("failed reaping pipelined cmd responsess\n");
+ buffer[0] = '\0';
+ if (rc == DEFER) errno = ERRNO_TLSFAILURE;
+ return FALSE;
+ }
+ }
+#endif
+
+/* This is a loop to read and concatenate the lines that make up a multi-line
response. */
for (;;)
{
- if ((count = read_response_line(inblock, ptr, size, timeout)) < 0)
+ if ((count = read_response_line(&sx->inblock, ptr, size, timelimit)) < 0)
return FALSE;
HDEBUG(D_transport|D_acl|D_v)
- debug_printf(" %s %s\n", (ptr == buffer)? "SMTP<<" : " ", ptr);
+ debug_printf_indent(" %s %s\n", ptr == buffer ? "SMTP<<" : " ", ptr);
/* Check the format of the response: it must start with three digits; if
these are followed by a space or end of line, the response is complete. If
size -= count + 1;
}
+#ifdef TCP_FASTOPEN
+ tfo_out_check(sx->cctx.sock);
+#endif
+
/* Return a value that depends on the SMTP return code. On some systems a
non-zero value of errno has been seen at this point, so ensure it is zero,
because the caller of this function looks at errno when FALSE is returned, to
git://git.exim.org / users / heiko / exim.git / blobdiff