*************************************************/
/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim Maintainers 2020 - 2021 */
/* See the file NOTICE for conditions of use and distribution. */
/* A number of functions for driving outgoing SMTP calls. */
which case the function does nothing
host_af AF_INET or AF_INET6 for the outgoing IP address
addr the mail address being handled (for setting errors)
- interface point this to the interface
+ interface point this to the interface if there is one defined
msg to add to any error message
Returns: TRUE on success, FALSE on failure, with error message
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_tainted2(expint, LOG_MAIN|LOG_PANIC, "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)))
+while ((iface = string_nextinlist(&expint, &sep, NULL, 0)))
{
- if (string_is_ip_address(iface, NULL) == 0)
+ int if_af = string_is_ip_address(iface, NULL);
+ if (if_af == 0)
{
addr->transport_return = PANIC;
addr->message = string_sprintf("\"%s\" is not a valid IP "
return FALSE;
}
- if (((Ustrchr(iface, ':') == NULL)? AF_INET:AF_INET6) == host_af)
+ if ((if_af == 4 ? AF_INET : AF_INET6) == host_af)
break;
}
-if (iface) *interface = string_copy(iface);
+*interface = iface;
return TRUE;
}
#ifdef TCP_FASTOPEN
+/* Try to record if TFO was attmepted and if it was successfully used. */
+
static void
tfo_out_check(int sock)
{
-# if defined(TCP_INFO) && defined(EXIM_HAVE_TCPI_UNACKED)
+static BOOL done_once = FALSE;
+
+if (done_once) return;
+done_once = TRUE;
+
+# ifdef __FreeBSD__
struct tcp_info tinfo;
socklen_t len = sizeof(tinfo);
-if (getsockopt(sock, IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0)
+/* A getsockopt TCP_FASTOPEN unfortunately returns "was-used" for a TFO/R as
+well as a TFO/C. Use what we can of the Linux hack below; reliability issues ditto. */
+switch (tcp_out_fastopen)
{
- 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 1:
- if (tinfo.tcpi_unacked > 1)
- {
- DEBUG(D_transport|D_v)
- debug_printf("TCP_FASTOPEN tcpi_unacked %d\n", tinfo.tcpi_unacked);
- tcp_out_fastopen = 2;
- }
- break;
+ case TFO_ATTEMPTED_NODATA:
+ if ( getsockopt(sock, IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
+ && tinfo.tcpi_state == TCPS_SYN_SENT
+ && tinfo.__tcpi_unacked > 0
+ )
+ {
+ DEBUG(D_transport|D_v)
+ debug_printf("TCP_FASTOPEN tcpi_unacked %d\n", tinfo.__tcpi_unacked);
+ tcp_out_fastopen = TFO_USED_NODATA;
+ }
+ break;
+ /*
+ case TFO_ATTEMPTED_DATA:
+ case TFO_ATTEMPTED_DATA:
+ if (tinfo.tcpi_options & TCPI_OPT_SYN_DATA) XXX no equvalent as of 12.2
+ */
+ }
-#ifdef notdef /* This seems to always fire, meaning that we cannot tell
- whether the server accepted data we sent. For now assume
- that it did. */
+switch (tcp_out_fastopen)
+ {
+ case TFO_ATTEMPTED_DATA: tcp_out_fastopen = TFO_USED_DATA; break;
+ default: break; /* compiler quietening */
+ }
- /* If there was data-on-SYN but we had to retrasnmit it, declare no TFO */
+# else /* Linux & Apple */
+# if defined(TCP_INFO) && defined(EXIM_HAVE_TCPI_UNACKED)
+struct tcp_info tinfo;
+socklen_t len = sizeof(tinfo);
- case 2:
- if (!(tinfo.tcpi_options & TCPI_OPT_SYN_DATA))
+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 = 0;
+ tcp_out_fastopen = TFO_NOT_USED;
}
- break;
-#endif
- }
+ break;
+ default: break; /* compiler quietening */
}
-# endif
+# endif
+# endif /* Linux & Apple */
}
#endif
-/* Arguments as for smtp_connect(), plus
- early_data if non-NULL, data to be sent - preferably in the TCP SYN segment
+/* Arguments:
+ host host item containing name and address and port
+ host_af AF_INET or AF_INET6
+ port TCP port number
+ interface outgoing interface address or NULL
+ tb transport
+ timeout timeout value or 0
+ early_data if non-NULL, idempotent data to be sent -
+ preferably in the TCP SYN segment
+ Special case: non-NULL but with NULL blob.data - caller is
+ client-data-first (eg. TLS-on-connect) and a lazy-TCP-connect is
+ acceptable.
Returns: connected socket number, or -1 with errno set
*/
#ifndef DISABLE_EVENT
deliver_host_address = host->address;
deliver_host_port = port;
-if (event_raise(tb->event_action, US"tcp:connect", NULL)) return -1;
+if (event_raise(tb->event_action, US"tcp:connect", NULL, &errno)) return -1;
#endif
if ((sock = ip_socket(SOCK_STREAM, host_af)) < 0) return -1;
/* Connect to the remote host, and add keepalive to the socket before returning
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. */
+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
{
#ifdef TCP_FASTOPEN
- if (verify_check_given_host(&ob->hosts_try_fastopen, host) == OK)
- fastopen_blob = early_data ? early_data : &tcp_fastopen_nodata;
+ /* See if TCP Fast Open usable. Default is a traditional 3WHS connect */
+ if (verify_check_given_host(CUSS &ob->hosts_try_fastopen, host) == OK)
+ {
+ if (!early_data)
+ fastopen_blob = &tcp_fastopen_nodata; /* TFO, with no data */
+ else if (early_data->data)
+ fastopen_blob = early_data; /* TFO, with data */
+# ifdef TCP_FASTOPEN_CONNECT
+ else
+ { /* expecting client data */
+ debug_printf(" set up lazy-connect\n");
+ setsockopt(sock, IPPROTO_TCP, TCP_FASTOPEN_CONNECT, US &on, sizeof(on));
+ /* fastopen_blob = NULL; lazy TFO, triggered by data write */
+ }
+# endif
+ }
#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)
+ {
+ /* We had some early-data to send, but couldn't do TFO */
+ HDEBUG(D_transport|D_acl|D_v)
+ debug_printf("sending %ld nonTFO early-data\n", (long)early_data->len);
+
+#ifdef TCP_QUICKACK_notdef
+ (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;
+ }
+#ifdef TCP_QUICKACK_notdef
+ /* Under TFO (with openssl & pipe-conn; testcase 4069, as of
+ 5.10.8-100.fc32.x86_64) this seems to be inop.
+ Perhaps overwritten when we (client) go -> ESTABLISHED on seeing the 3rd-ACK?
+ For that case, added at smtp_reap_banner(). */
+ (void) setsockopt(sock, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
+#endif
}
/* Either bind() or connect() failed */
{
HDEBUG(D_transport|D_acl|D_v)
{
- debug_printf_indent("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_indent("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
- if (fastopen_blob) tfo_out_check(sock);
+ tfo_out_check(sock);
#endif
return sock;
}
{
if (host->port != PORT_NONE)
{
- HDEBUG(D_transport|D_acl|D_v)
+ 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;
host->address will always be an IPv4 address.
Arguments:
- host host item containing name and address and port
- host_af AF_INET or AF_INET6
- 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
+ Special case: non-NULL but with NULL blob.data - caller is
+ client-data-first (eg. TLS-on-connect) and a lazy-TCP-connect is
+ acceptable.
Returns: connected socket number, or -1 with errno set
*/
int
-smtp_connect(host_item *host, int host_af, uschar *interface,
- int timeout, transport_instance * tb)
+smtp_connect(smtp_connect_args * sc, const blob * early_data)
{
-int port = host->port;
-#ifdef SUPPORT_SOCKS
-smtp_transport_options_block * ob =
- (smtp_transport_options_block *)tb->options_block;
-#endif
+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_indent("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, NULL);
+return smtp_sock_connect(sc->host, sc->host_af, port, sc->interface,
+ sc->tblock, ob->connect_timeout, early_data);
}
HDEBUG(D_transport|D_acl) debug_printf_indent("cmd buf flush %d bytes%s\n", n,
more ? " (more expected)" : "");
-#ifdef SUPPORT_TLS
+#ifndef DISABLE_TLS
if (outblock->cctx->tls_ctx)
rc = tls_write(outblock->cctx->tls_ctx, outblock->buffer, n, more);
else
#endif
- rc = send(outblock->cctx->sock, outblock->buffer, n,
+
+ {
+ 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
+ more ? MSG_MORE : 0
#else
- 0
+ 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)
{
any error message.
Arguments:
- outblock contains buffer for pipelining, and socket
+ 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.
*/
int
-smtp_write_command(smtp_outblock * outblock, int mode, 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, 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_indent(" SMTP>> %s\n", big_buffer);
+ HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP%c> %s\n",
+ mode == SCMD_BUFFER ? '|' : mode == SCMD_MORE ? '+' : '>',
+ big_buffer);
}
if (mode != SCMD_BUFFER)
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
+ -1 otherwise, with errno set, and inblock->ptr adjusted
*/
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;
{
*p = 0; /* Leave malformed line for error message */
errno = ERRNO_SMTPFORMAT;
+ inblock->ptr = ptr;
return -1;
}
}
/* Need to read a new input packet. */
- if((rc = ip_recv(cctx, inblock->buffer, inblock->buffersize, timeout)) <= 0)
+ if((rc = ip_recv(cctx, inblock->buffer, inblock->buffersize, timelimit)) <= 0)
{
- DEBUG(D_deliver|D_transport|D_acl)
+ DEBUG(D_deliver|D_transport|D_acl|D_v)
debug_printf_indent(errno ? " SMTP(%s)<<\n" : " SMTP(closed)<<\n",
strerror(errno));
break;
/* Get here if there has been some kind of recv() error; errno is set, but we
ensure that the result buffer is empty before returning. */
+inblock->ptr = inblock->ptrend = inblock->buffer;
*buffer = 0;
return -1;
}
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
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 */
+#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_indent(" %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 / exim.git / blobdiff