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-rw-r--r--src/smtp_out.c936
1 files changed, 936 insertions, 0 deletions
diff --git a/src/smtp_out.c b/src/smtp_out.c
new file mode 100644
index 0000000..7b7bdf7
--- /dev/null
+++ b/src/smtp_out.c
@@ -0,0 +1,936 @@
+/*************************************************
+* Exim - an Internet mail transport agent *
+*************************************************/
+
+/* Copyright (c) The Exim Maintainers 2020 - 2022 */
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+/* A number of functions for driving outgoing SMTP calls. */
+
+
+#include "exim.h"
+#include "transports/smtp.h"
+
+
+
+/*************************************************
+* Find an outgoing interface *
+*************************************************/
+
+/* This function is called from the smtp transport and also from the callout
+code in verify.c. Its job is to expand a string to get a list of interfaces,
+and choose a suitable one (IPv4 or IPv6) for the outgoing address.
+
+Arguments:
+ istring string interface setting, may be NULL, meaning "any", in
+ 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 if there is one defined
+ msg to add to any error message
+
+Returns: TRUE on success, FALSE on failure, with error message
+ set in addr and transport_return set to PANIC
+*/
+
+BOOL
+smtp_get_interface(uschar *istring, int host_af, address_item *addr,
+ uschar **interface, uschar *msg)
+{
+const uschar * expint;
+uschar *iface;
+int sep = 0;
+
+if (!istring) return TRUE;
+
+if (!(expint = expand_string(istring)))
+ {
+ 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;
+ }
+
+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, 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 "
+ "address for the \"interface\" option for %s",
+ iface, msg);
+ return FALSE;
+ }
+
+ if ((if_af == 4 ? AF_INET : AF_INET6) == host_af)
+ break;
+ }
+
+*interface = iface;
+return TRUE;
+}
+
+
+
+/*************************************************
+* Find an outgoing port *
+*************************************************/
+
+/* This function is called from the smtp transport and also from the callout
+code in verify.c. Its job is to find a port number. Note that getservbyname()
+produces the number in network byte order.
+
+Arguments:
+ rstring raw (unexpanded) string representation of the port
+ addr the mail address being handled (for setting errors)
+ port stick the port in here
+ msg for adding to error message
+
+Returns: TRUE on success, FALSE on failure, with error message set
+ in addr, and transport_return set to PANIC
+*/
+
+BOOL
+smtp_get_port(uschar *rstring, address_item *addr, int *port, uschar *msg)
+{
+uschar *pstring = expand_string(rstring);
+
+if (!pstring)
+ {
+ addr->transport_return = PANIC;
+ addr->message = string_sprintf("failed to expand \"%s\" (\"port\" option) "
+ "for %s: %s", rstring, msg, expand_string_message);
+ return FALSE;
+ }
+
+if (isdigit(*pstring))
+ {
+ uschar *end;
+ *port = Ustrtol(pstring, &end, 0);
+ if (end != pstring + Ustrlen(pstring))
+ {
+ addr->transport_return = PANIC;
+ addr->message = string_sprintf("invalid port number for %s: %s", msg,
+ pstring);
+ return FALSE;
+ }
+ }
+
+else
+ {
+ struct servent *smtp_service = getservbyname(CS pstring, "tcp");
+ if (!smtp_service)
+ {
+ addr->transport_return = PANIC;
+ addr->message = string_sprintf("TCP port \"%s\" is not defined for %s",
+ pstring, msg);
+ return FALSE;
+ }
+ *port = ntohs(smtp_service->s_port);
+ }
+
+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)
+{
+static BOOL done_once = FALSE;
+
+if (done_once) return;
+done_once = TRUE;
+
+# ifdef __FreeBSD__
+struct tcp_info tinfo;
+socklen_t len = sizeof(tinfo);
+
+/* 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)
+ {
+ 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
+ */
+ }
+
+switch (tcp_out_fastopen)
+ {
+ 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
+
+
+/* Create and bind a socket, given the connect-args.
+Update those with the state. Return the fd, or -1 with errno set.
+*/
+
+int
+smtp_boundsock(smtp_connect_args * sc)
+{
+transport_instance * tb = sc->tblock;
+smtp_transport_options_block * ob =
+ (smtp_transport_options_block *)tb->options_block;
+const uschar * dscp = ob->dscp;
+int sock, dscp_value, dscp_level, dscp_option;
+
+if ((sock = ip_socket(SOCK_STREAM, sc->host_af)) < 0)
+ return -1;
+
+/* Set TCP_NODELAY; Exim does its own buffering. */
+
+if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, US &on, sizeof(on)))
+ HDEBUG(D_transport|D_acl|D_v)
+ 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, sc->host_af, &dscp_level, &dscp_option, &dscp_value))
+ {
+ HDEBUG(D_transport|D_acl|D_v)
+ 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_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 (sc->host_af == AF_INET6 &&
+ dscp_lookup(dscp, AF_INET, &dscp_level, &dscp_option, &dscp_value))
+ (void) setsockopt(sock, dscp_level, dscp_option, &dscp_value, sizeof(dscp_value));
+ }
+
+/* Bind to a specific interface if requested. Caller must ensure the interface
+is the same type (IPv4 or IPv6) as the outgoing address. */
+
+if (sc->interface)
+ {
+ union sockaddr_46 interface_sock;
+ EXIM_SOCKLEN_T size = sizeof(interface_sock);
+
+ if ( ip_bind(sock, sc->host_af, sc->interface, 0) < 0
+ || getsockname(sock, (struct sockaddr *) &interface_sock, &size) < 0
+ )
+ {
+ HDEBUG(D_transport|D_acl|D_v)
+ debug_printf_indent("unable to bind outgoing SMTP call to %s: %s", sc->interface,
+ strerror(errno));
+ close(sock);
+ return -1;
+ }
+ sending_ip_address = host_ntoa(-1, &interface_sock, NULL, &sending_port);
+ }
+
+sc->sock = sock;
+return sock;
+}
+
+
+/* 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
+*/
+
+int
+smtp_sock_connect(smtp_connect_args * sc, int timeout, const blob * early_data)
+{
+smtp_transport_options_block * ob =
+ (smtp_transport_options_block *)sc->tblock->options_block;
+int sock;
+int save_errno = 0;
+const blob * fastopen_blob = NULL;
+
+
+#ifndef DISABLE_EVENT
+deliver_host_address = sc->host->address;
+deliver_host_port = sc->host->port;
+if (event_raise(sc->tblock->event_action, US"tcp:connect", NULL, &errno)) return -1;
+#endif
+
+if ( (sock = sc->sock) < 0
+ && (sock = smtp_boundsock(sc)) < 0)
+ save_errno = errno;
+sc->sock = -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. If there is
+early-data but no TFO support, send it after connecting. */
+
+if (!save_errno)
+ {
+#ifdef TCP_FASTOPEN
+ /* See if TCP Fast Open usable. Default is a traditional 3WHS connect */
+ if (verify_check_given_host(CUSS &ob->hosts_try_fastopen, sc->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, sc->host_af, sc->host->address, sc->host->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
+ }
+
+if (!save_errno)
+ {
+ union sockaddr_46 interface_sock;
+ EXIM_SOCKLEN_T size = sizeof(interface_sock);
+
+ /* Both bind() and connect() succeeded, and any early-data */
+
+ 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
+ {
+ log_write(0, LOG_MAIN | ((errno == ECONNRESET)? 0 : LOG_PANIC),
+ "getsockname() failed: %s", strerror(errno));
+ close(sock);
+ return -1;
+ }
+
+ if (ob->keepalive) ip_keepalive(sock, sc->host->address, TRUE);
+#ifdef TCP_FASTOPEN
+ tfo_out_check(sock);
+#endif
+ return sock;
+ }
+
+/* Either bind() or connect() failed */
+
+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(timeout));
+ debug_printf("\n");
+ }
+(void)close(sock);
+errno = save_errno;
+return -1;
+}
+
+
+
+
+
+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 *
+*************************************************/
+
+/* Create a socket, and connect it to a remote host. IPv6 addresses are
+detected by checking for a colon in the address. AF_INET6 is defined even on
+non-IPv6 systems, to enable the code to be less messy. However, on such systems
+host->address will always be an IPv4 address.
+
+Arguments:
+ 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(smtp_connect_args * sc, const blob * early_data)
+{
+int port = sc->host->port;
+smtp_transport_options_block * ob = sc->ob;
+
+callout_address = string_sprintf("[%s]:%d", sc->host->address, port);
+
+HDEBUG(D_transport|D_acl|D_v)
+ {
+ uschar * s = US" ";
+ 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... ", sc->host->name, callout_address, s);
+ }
+
+/* Create and connect the socket */
+
+#ifdef SUPPORT_SOCKS
+if (ob->socks_proxy)
+ {
+ 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(sc, ob->connect_timeout, early_data);
+}
+
+
+/*************************************************
+* Flush outgoing command buffer *
+*************************************************/
+
+/* This function is called only from smtp_write_command() below. It flushes
+the buffer of outgoing commands. There is more than one in the buffer only when
+pipelining.
+
+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, int mode)
+{
+int rc;
+int n = outblock->ptr - outblock->buffer;
+BOOL more = mode == SCMD_MORE;
+client_conn_ctx * cctx;
+
+HDEBUG(D_transport|D_acl) debug_printf_indent("cmd buf flush %d bytes%s\n", n,
+ more ? " (more expected)" : "");
+
+if (!(cctx = outblock->cctx))
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC, "null conn-context pointer");
+ errno = 0;
+ return FALSE;
+ }
+
+#ifndef DISABLE_TLS
+if (cctx->tls_ctx) /*XXX have seen a null cctx here, rvfy sending QUIT, hence check above */
+ rc = tls_write(cctx->tls_ctx, outblock->buffer, n, more);
+else
+#endif
+
+ {
+ 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 ( (cctx->sock = smtp_connect(outblock->conn_args, &early_data))
+ < 0)
+ return FALSE;
+ outblock->conn_args = NULL;
+ rc = n;
+ }
+ else
+ {
+ rc = send(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(cctx->sock, IPPROTO_TCP, TCP_CORK, &off, sizeof(off));
+#endif
+ }
+ }
+
+if (rc <= 0)
+ {
+ HDEBUG(D_transport|D_acl) debug_printf_indent("send failed: %s\n", strerror(errno));
+ return FALSE;
+ }
+
+outblock->ptr = outblock->buffer;
+outblock->cmd_count = 0;
+return TRUE;
+}
+
+
+
+/* This might be called both due to callout and then from delivery.
+Use memory that will not be released between those phases.
+*/
+static void
+smtp_debug_resp(const uschar * buf)
+{
+#ifndef DISABLE_CLIENT_CMD_LOG
+int old_pool = store_pool;
+store_pool = POOL_PERM;
+client_cmd_log = string_append_listele_n(client_cmd_log, ':', buf,
+ buf[3] == ' ' ? 3 : 4);
+store_pool = old_pool;
+#endif
+}
+
+
+/*************************************************
+* Write SMTP command *
+*************************************************/
+
+/* The formatted command is left in big_buffer so that it can be reflected in
+any error message.
+
+Arguments:
+ 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.
+ ... data for the format
+
+Returns: 0 if command added to pipelining buffer, with nothing transmitted
+ +n if n commands transmitted (may still have buffered the new one)
+ -1 on error, with errno set
+*/
+
+int
+smtp_write_command(void * sx, int mode, const char * format, ...)
+{
+smtp_outblock * outblock = &((smtp_context *)sx)->outblock;
+int rc = 0;
+
+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(&gs, SVFMT_TAINT_NOCHK, CS format, ap))
+ log_write(0, LOG_MAIN|LOG_PANIC_DIE, "overlong write_command in outgoing "
+ "SMTP");
+ va_end(ap);
+ string_from_gstring(&gs);
+
+ if (gs.ptr > outblock->buffersize)
+ log_write(0, LOG_MAIN|LOG_PANIC_DIE, "overlong write_command in outgoing "
+ "SMTP");
+
+ if (gs.ptr > outblock->buffersize - (outblock->ptr - outblock->buffer))
+ {
+ rc = outblock->cmd_count; /* flush resets */
+ if (!flush_buffer(outblock, SCMD_FLUSH)) return -1;
+ }
+
+ Ustrncpy(outblock->ptr, gs.s, gs.ptr);
+ outblock->ptr += gs.ptr;
+ outblock->cmd_count++;
+ 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.
+ The AUTH command itself gets any data flattened. Other lines are flattened
+ completely. */
+
+ if (outblock->authenticating)
+ {
+ uschar *p = big_buffer;
+ if (Ustrncmp(big_buffer, "AUTH ", 5) == 0)
+ {
+ p += 5;
+ while (isspace(*p)) p++;
+ while (!isspace(*p)) p++;
+ while (isspace(*p)) p++;
+ }
+ while (*p) *p++ = '*';
+ }
+
+ smtp_debug_cmd(big_buffer, mode);
+ }
+
+if (mode != SCMD_BUFFER)
+ {
+ rc += outblock->cmd_count; /* flush resets */
+ if (!flush_buffer(outblock, mode)) return -1;
+ }
+
+return rc;
+}
+
+
+
+/*************************************************
+* Read one line of SMTP response *
+*************************************************/
+
+/* This function reads one line of SMTP response from the server host. This may
+not be a complete response - it could be just part of a multiline response. We
+have to use a buffer for incoming packets, because when pipelining or using
+LMTP, there may well be more than one response in a single packet. This
+function is called only from the one that follows.
+
+Arguments:
+ inblock the SMTP input block (contains holding buffer, socket, etc.)
+ buffer where to put the line
+ size space available for the line
+ 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, and inblock->ptr adjusted
+*/
+
+static int
+read_response_line(smtp_inblock *inblock, uschar *buffer, int size, time_t timelimit)
+{
+uschar *p = buffer;
+uschar *ptr = inblock->ptr;
+uschar *ptrend = inblock->ptrend;
+client_conn_ctx * cctx = inblock->cctx;
+
+/* Loop for reading multiple packets or reading another packet after emptying
+a previously-read one. */
+
+for (;;)
+ {
+ int rc;
+
+ /* If there is data in the input buffer left over from last time, copy
+ characters from it until the end of a line, at which point we can return,
+ having removed any whitespace (which will include CR) at the end of the line.
+ The rules for SMTP say that lines end in CRLF, but there are have been cases
+ of hosts using just LF, and other MTAs are reported to handle this, so we
+ just look for LF. If we run out of characters before the end of a line,
+ carry on to read the next incoming packet. */
+
+ while (ptr < ptrend)
+ {
+ int c = *ptr++;
+ if (c == '\n')
+ {
+ while (p > buffer && isspace(p[-1])) p--;
+ *p = 0;
+ inblock->ptr = ptr;
+ return p - buffer;
+ }
+ *p++ = c;
+ if (--size < 4)
+ {
+ *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, 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_indent("read response data: size=%d\n", rc);
+ }
+
+/* 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;
+}
+
+
+
+
+
+/*************************************************
+* Read SMTP response *
+*************************************************/
+
+/* This function reads an SMTP response with a timeout, and returns the
+response in the given buffer, as a string. A multiline response will contain
+newline characters between the lines. The function also analyzes the first
+digit of the reply code and returns FALSE if it is not acceptable. FALSE is
+also returned after a reading error. In this case buffer[0] will be zero, and
+the error code will be in errno.
+
+Arguments:
+ 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, 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(void * sx0, uschar * buffer, int size, int okdigit,
+ int timeout)
+{
+smtp_context * sx = sx0;
+uschar * ptr = buffer;
+int count = 0;
+time_t timelimit = time(NULL) + timeout;
+BOOL yield = FALSE;
+
+errno = 0; /* Ensure errno starts out zero */
+buffer[0] = '\0';
+
+#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");
+ if (rc == DEFER) errno = ERRNO_TLSFAILURE;
+ goto out;
+ }
+ }
+#endif
+
+/* This is a loop to read and concatenate the lines that make up a multi-line
+response. */
+
+for (;;)
+ {
+ 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);
+
+ /* 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
+ they are followed by '-' this is a multi-line response and we must look for
+ another line until the final line is reached. The only use made of multi-line
+ responses is to pass them back as error messages. We therefore just
+ concatenate them all within the buffer, which should be large enough to
+ accept any reasonable number of lines. */
+
+ if (count < 3 ||
+ !isdigit(ptr[0]) ||
+ !isdigit(ptr[1]) ||
+ !isdigit(ptr[2]) ||
+ (ptr[3] != '-' && ptr[3] != ' ' && ptr[3] != 0))
+ {
+ errno = ERRNO_SMTPFORMAT; /* format error */
+ goto out;
+ }
+
+ /* If the line we have just read is a terminal line, line, we are done.
+ Otherwise more data has to be read. */
+
+ if (ptr[3] != '-') break;
+
+ /* Move the reading pointer upwards in the buffer and insert \n between the
+ components of a multiline response. Space is left for this by read_response_
+ line(). */
+
+ ptr += count;
+ *ptr++ = '\n';
+ 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
+distinguish between an unexpected return code and other errors such as
+timeouts, lost connections, etc. */
+
+errno = 0;
+yield = buffer[0] == okdigit;
+
+out:
+ smtp_debug_resp(buffer);
+ return yield;
+}
+
+/* End of smtp_out.c */
+/* vi: aw ai sw=2
+*/
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-18 23:21:24 +0000