-/* $Cambridge: exim/src/src/smtp_in.c,v 1.50 2007/01/15 15:59:22 ph10 Exp $ */
-
/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2007 */
+/* Copyright (c) University of Cambridge 1995 - 2009 */
/* See the file NOTICE for conditions of use and distribution. */
/* Functions for handling an incoming SMTP call. */
int allow_severity = LOG_INFO;
int deny_severity = LOG_NOTICE;
+uschar *tcp_wrappers_name;
#endif
/* Size of buffer for reading SMTP commands. We used to use 512, as defined
by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
commands that accept arguments, and this in particular applies to AUTH, where
-the data can be quite long. */
+the data can be quite long. More recently this value was 2048 in Exim;
+however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
+such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
+The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
+we need room to handle large base64-encoded AUTHs for GSSAPI.
+*/
-#define smtp_cmd_buffer_size 2048
+#define smtp_cmd_buffer_size 16384
/* Size of buffer for reading SMTP incoming packets */
/* Structure for SMTP command list */
typedef struct {
- char *name;
+ const char *name;
int len;
short int cmd;
short int has_arg;
static BOOL helo_accept_junk;
static BOOL count_nonmail;
static BOOL pipelining_advertised;
+static BOOL rcpt_smtp_response_same;
+static BOOL rcpt_in_progress;
static int nonmail_command_count;
+static BOOL smtp_exit_function_called = 0;
static int synprot_error_count;
static int unknown_command_count;
static int sync_cmd_limit;
static int smtp_write_error = 0;
+static uschar *rcpt_smtp_response;
+static uschar *smtp_data_buffer;
+static uschar *smtp_cmd_data;
+
/* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
final fields of all except AUTH are forced TRUE at the start of a new message
setup, to allow one of each between messages that is not counted as a nonmail
else smtp_had_eof = 1;
return EOF;
}
+#ifndef DISABLE_DKIM
+ dkim_exim_verify_feed(smtp_inbuffer, rc);
+#endif
smtp_inend = smtp_inbuffer + rc;
smtp_inptr = smtp_inbuffer;
}
+/*************************************************
+* Test for characters in the SMTP buffer *
+*************************************************/
+
+/* Used at the end of a message
+
+Arguments: none
+Returns: TRUE/FALSE
+*/
+
+BOOL
+smtp_buffered(void)
+{
+return smtp_inptr < smtp_inend;
+}
+
+
/*************************************************
* Write formatted string to SMTP channel *
*/
void
-smtp_printf(char *format, ...)
+smtp_printf(const char *format, ...)
{
va_list ap;
+va_start(ap, format);
+smtp_vprintf(format, ap);
+va_end(ap);
+}
+
+/* This is split off so that verify.c:respond_printf() can, in effect, call
+smtp_printf(), bearing in mind that in C a vararg function can't directly
+call another vararg function, only a function which accepts a va_list. */
+
+void
+smtp_vprintf(const char *format, va_list ap)
+{
+BOOL yield;
+
+yield = string_vformat(big_buffer, big_buffer_size, format, ap);
+
DEBUG(D_receive)
{
- uschar *cr, *end;
- va_start(ap, format);
- (void) string_vformat(big_buffer, big_buffer_size, format, ap);
- va_end(ap);
- end = big_buffer + Ustrlen(big_buffer);
- while ((cr = Ustrchr(big_buffer, '\r')) != NULL) /* lose CRs */
- memmove(cr, cr + 1, (end--) - cr);
- debug_printf("SMTP>> %s", big_buffer);
+ void *reset_point = store_get(0);
+ uschar *msg_copy, *cr, *end;
+ msg_copy = string_copy(big_buffer);
+ end = msg_copy + Ustrlen(msg_copy);
+ while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
+ memmove(cr, cr + 1, (end--) - cr);
+ debug_printf("SMTP>> %s", msg_copy);
+ store_reset(reset_point);
}
-va_start(ap, format);
+if (!yield)
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
+ smtp_closedown(US"Unexpected error");
+ exim_exit(EXIT_FAILURE);
+ }
+
+/* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
+have had the same. Note: this code is also present in smtp_respond(). It would
+be tidier to have it only in one place, but when it was added, it was easier to
+do it that way, so as not to have to mess with the code for the RCPT command,
+which sometimes uses smtp_printf() and sometimes smtp_respond(). */
-/* If in a TLS session we have to format the string, and then write it using a
-TLS function. */
+if (rcpt_in_progress)
+ {
+ if (rcpt_smtp_response == NULL)
+ rcpt_smtp_response = string_copy(big_buffer);
+ else if (rcpt_smtp_response_same &&
+ Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
+ rcpt_smtp_response_same = FALSE;
+ rcpt_in_progress = FALSE;
+ }
+
+/* Now write the string */
#ifdef SUPPORT_TLS
if (tls_active >= 0)
{
- if (!string_vformat(big_buffer, big_buffer_size, format, ap))
- {
- log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf");
- smtp_closedown(US"Unexpected error");
- exim_exit(EXIT_FAILURE);
- }
if (tls_write(big_buffer, Ustrlen(big_buffer)) < 0) smtp_write_error = -1;
}
else
#endif
-/* Otherwise, just use the standard library function. */
-
-if (vfprintf(smtp_out, format, ap) < 0) smtp_write_error = -1;
-va_end(ap);
+if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
}
host_and_ident(FALSE));
if (smtp_batched_input)
moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
-smtp_printf("421 %s: SMTP command timeout - closing connection\r\n",
- smtp_active_hostname);
-mac_smtp_fflush();
+smtp_notquit_exit(US"command-timeout", US"421",
+ US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
exim_exit(EXIT_FAILURE);
}
log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
if (smtp_batched_input)
moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
-smtp_printf("421 %s: Service not available - closing connection\r\n",
- smtp_active_hostname);
+smtp_notquit_exit(US"signal-exit", US"421",
+ US"%s: Service not available - closing connection", smtp_active_hostname);
exim_exit(EXIT_FAILURE);
}
+
/*************************************************
* Read one command line *
*************************************************/
!sender_host_notsocket) /* Really is a socket */
return BADSYN_CMD;
- /* Point after the command, but don't skip over leading spaces till after
- the following test, so that if it fails, the command name can easily be
- logged. */
+ /* The variables $smtp_command and $smtp_command_argument point into the
+ unmodified input buffer. A copy of the latter is taken for actual
+ processing, so that it can be chopped up into separate parts if necessary,
+ for example, when processing a MAIL command options such as SIZE that can
+ follow the sender address. */
smtp_cmd_argument = smtp_cmd_buffer + p->len;
+ while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
+ Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
+ smtp_cmd_data = smtp_data_buffer;
/* Count non-mail commands from those hosts that are controlled in this
way. The default is all hosts. We don't waste effort checking the list
return TOO_MANY_NONMAIL_CMD;
}
- /* Get the data pointer over leading spaces and return; if there is data
- for a command that does not expect it, give the error centrally here. */
+ /* If there is data for a command that does not expect it, generate the
+ error here. */
- while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
- return (p->has_arg || *smtp_cmd_argument == 0)? p->cmd : BADARG_CMD;
+ return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
}
}
+/*************************************************
+* Recheck synchronization *
+*************************************************/
+
+/* Synchronization checks can never be perfect because a packet may be on its
+way but not arrived when the check is done. Such checks can in any case only be
+done when TLS is not in use. Normally, the checks happen when commands are
+read: Exim ensures that there is no more input in the input buffer. In normal
+cases, the response to the command will be fast, and there is no further check.
+
+However, for some commands an ACL is run, and that can include delays. In those
+cases, it is useful to do another check on the input just before sending the
+response. This also applies at the start of a connection. This function does
+that check by means of the select() function, as long as the facility is not
+disabled or inappropriate. A failure of select() is ignored.
+
+When there is unwanted input, we read it so that it appears in the log of the
+error.
+
+Arguments: none
+Returns: TRUE if all is well; FALSE if there is input pending
+*/
+
+static BOOL
+check_sync(void)
+{
+int fd, rc;
+fd_set fds;
+struct timeval tzero;
+
+if (!smtp_enforce_sync || sender_host_address == NULL ||
+ sender_host_notsocket || tls_active >= 0)
+ return TRUE;
+
+fd = fileno(smtp_in);
+FD_ZERO(&fds);
+FD_SET(fd, &fds);
+tzero.tv_sec = 0;
+tzero.tv_usec = 0;
+rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
+
+if (rc <= 0) return TRUE; /* Not ready to read */
+rc = smtp_getc();
+if (rc < 0) return TRUE; /* End of file or error */
+
+smtp_ungetc(rc);
+rc = smtp_inend - smtp_inptr;
+if (rc > 150) rc = 150;
+smtp_inptr[rc] = 0;
+return FALSE;
+}
+
+
+
/*************************************************
* Forced closedown of call *
*************************************************/
except QUIT. The existence of an SMTP call is detected by the non-NULLness of
smtp_in.
-Argument: SMTP reply string to send, excluding the code
+Arguments:
+ message SMTP reply string to send, excluding the code
+
Returns: nothing
*/
s = string_append(s, &size, &ptr, 2, US" CV=",
tls_certificate_verified? "yes":"no");
if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_peerdn != NULL)
- s = string_append(s, &size, &ptr, 3, US" DN=\"", tls_peerdn, US"\"");
+ s = string_append(s, &size, &ptr, 3, US" DN=\"",
+ string_printing(tls_peerdn), US"\"");
#endif
sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
* Extract SMTP command option *
*************************************************/
-/* This function picks the next option setting off the end of smtp_cmd_argument. It
+/* This function picks the next option setting off the end of smtp_cmd_data. It
is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
things that can appear there.
extract_option(uschar **name, uschar **value)
{
uschar *n;
-uschar *v = smtp_cmd_argument + Ustrlen(smtp_cmd_argument) -1;
+uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
while (isspace(*v)) v--;
v[1] = 0;
-while (v > smtp_cmd_argument && *v != '=' && !isspace(*v)) v--;
+while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
if (*v != '=') return FALSE;
n = v;
message_size = -1;
acl_added_headers = NULL;
queue_only_policy = FALSE;
+rcpt_smtp_response = NULL;
+rcpt_smtp_response_same = TRUE;
+rcpt_in_progress = FALSE;
deliver_freeze = FALSE; /* Can be set by ACL */
freeze_tell = freeze_tell_config; /* Can be set by ACL */
fake_response = OK; /* Can be set by ACL */
bmi_run = 0;
bmi_verdicts = NULL;
#endif
-#ifdef EXPERIMENTAL_DOMAINKEYS
-dk_do_verify = 0;
+#ifndef DISABLE_DKIM
+dkim_signers = NULL;
+dkim_disable_verify = FALSE;
+dkim_collect_input = FALSE;
#endif
#ifdef EXPERIMENTAL_SPF
spf_header_comment = NULL;
case HELO_CMD:
case EHLO_CMD:
- check_helo(smtp_cmd_argument);
+ check_helo(smtp_cmd_data);
/* Fall through */
case RSET_CMD:
/* The function moan_smtp_batch() does not return. */
moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
- if (smtp_cmd_argument[0] == 0)
+ if (smtp_cmd_data[0] == 0)
/* The function moan_smtp_batch() does not return. */
moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
/* Apply SMTP rewrite */
raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
- rewrite_one(smtp_cmd_argument, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
- US"", global_rewrite_rules) : smtp_cmd_argument;
+ rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
+ US"", global_rewrite_rules) : smtp_cmd_data;
/* Extract the address; the TRUE flag allows <> as valid */
/* The function moan_smtp_batch() does not return. */
moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
- if (smtp_cmd_argument[0] == 0)
+ if (smtp_cmd_data[0] == 0)
/* The function moan_smtp_batch() does not return. */
moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
recipient address */
recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
- rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
- global_rewrite_rules) : smtp_cmd_argument;
+ rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
+ global_rewrite_rules) : smtp_cmd_data;
/* rfc821_domains = TRUE; << no longer needed */
recipient = parse_extract_address(recipient, &errmess, &start, &end,
smtp_delay_mail = smtp_rlm_base;
auth_advertised = FALSE;
pipelining_advertised = FALSE;
+pipelining_enable = TRUE;
sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
+smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
memset(sender_host_cache, 0, sizeof(sender_host_cache));
acl_var_c = NULL;
-/* Allow for trailing 0 in the command buffer. */
+/* Allow for trailing 0 in the command and data buffers. */
-smtp_cmd_buffer = (uschar *)malloc(smtp_cmd_buffer_size + 1);
+smtp_cmd_buffer = (uschar *)malloc(2*smtp_cmd_buffer_size + 2);
if (smtp_cmd_buffer == NULL)
log_write(0, LOG_MAIN|LOG_PANIC_DIE,
"malloc() failed for SMTP command buffer");
+smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
/* For batched input, the protocol setting can be overridden from the
command line by a trusted caller. */
receive_ungetc = smtp_ungetc;
receive_feof = smtp_feof;
receive_ferror = smtp_ferror;
+receive_smtp_buffered = smtp_buffered;
smtp_inptr = smtp_inend = smtp_inbuffer;
smtp_had_eof = smtp_had_error = 0;
smtps port for use with older style SSL MTAs. */
#ifdef SUPPORT_TLS
- if (tls_on_connect && tls_server_start(tls_require_ciphers) != OK)
+ if (tls_on_connect &&
+ tls_server_start(tls_require_ciphers,
+ gnutls_require_mac, gnutls_require_kx, gnutls_require_proto) != OK)
return FALSE;
#endif
#ifdef USE_TCP_WRAPPERS
errno = 0;
- if (!hosts_ctl("exim",
+ tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
+ if (tcp_wrappers_name == NULL)
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
+ "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
+ expand_string_message);
+ }
+ if (!hosts_ctl(tcp_wrappers_name,
(sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
(sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
(sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
}
#endif
- /* Check for reserved slots. Note that the count value doesn't include
- this process, as it gets upped in the parent process. */
+ /* Check for reserved slots. The value of smtp_accept_count has already been
+ incremented to include this process. */
if (smtp_accept_max > 0 &&
- smtp_accept_count + 1 > smtp_accept_max - smtp_accept_reserve)
+ smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
{
if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
{
log_write(L_connection_reject,
LOG_MAIN, "temporarily refused connection from %s: not in "
"reserve list: connected=%d max=%d reserve=%d%s",
- host_and_ident(FALSE), smtp_accept_count, smtp_accept_max,
+ host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
smtp_printf("421 %s: Too many concurrent SMTP connections; "
"please try again later\r\n", smtp_active_hostname);
/* Before we write the banner, check that there is no input pending, unless
this synchronisation check is disabled. */
-if (smtp_enforce_sync && sender_host_address != NULL && !sender_host_notsocket)
+if (!check_sync())
{
- fd_set fds;
- struct timeval tzero;
- tzero.tv_sec = 0;
- tzero.tv_usec = 0;
- FD_ZERO(&fds);
- FD_SET(fileno(smtp_in), &fds);
- if (select(fileno(smtp_in) + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL,
- &tzero) > 0)
- {
- int rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
- if (rc > 0)
- {
- if (rc > 150) rc = 150;
- smtp_inbuffer[rc] = 0;
- log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
- "synchronization error (input sent without waiting for greeting): "
- "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
- string_printing(smtp_inbuffer));
- smtp_printf("554 SMTP synchronization error\r\n");
- return FALSE;
- }
- }
+ log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
+ "synchronization error (input sent without waiting for greeting): "
+ "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
+ string_printing(smtp_inptr));
+ smtp_printf("554 SMTP synchronization error\r\n");
+ return FALSE;
}
/* Now output the banner */
esclen = codelen - 4;
}
+/* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
+have had the same. Note: this code is also present in smtp_printf(). It would
+be tidier to have it only in one place, but when it was added, it was easier to
+do it that way, so as not to have to mess with the code for the RCPT command,
+which sometimes uses smtp_printf() and sometimes smtp_respond(). */
+
+if (rcpt_in_progress)
+ {
+ if (rcpt_smtp_response == NULL)
+ rcpt_smtp_response = string_copy(msg);
+ else if (rcpt_smtp_response_same &&
+ Ustrcmp(rcpt_smtp_response, msg) != 0)
+ rcpt_smtp_response_same = FALSE;
+ rcpt_in_progress = FALSE;
+ }
+
+/* Not output the message, splitting it up into multiple lines if necessary. */
+
for (;;)
{
uschar *nl = Ustrchr(msg, '\n');
#endif
(where == ACL_WHERE_PREDATA)? US"DATA" :
(where == ACL_WHERE_DATA)? US"after DATA" :
- (smtp_cmd_argument == NULL)?
+ (smtp_cmd_data == NULL)?
string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]) :
- string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_argument);
+ string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data);
if (drop) rc = FAIL;
if (sender_verified_failed != NULL &&
!testflag(sender_verified_failed, af_sverify_told))
{
+ BOOL save_rcpt_in_progress = rcpt_in_progress;
+ rcpt_in_progress = FALSE; /* So as not to treat these as the error */
+
setflag(sender_verified_failed, af_sverify_told);
if (rc != FAIL || (log_extra_selector & LX_sender_verify_fail) != 0)
"Verification failed for <%s>\n%s",
sender_verified_failed->address,
sender_verified_failed->user_message));
+
+ rcpt_in_progress = save_rcpt_in_progress;
}
/* Sort out text for logging */
log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
smtp_get_connection_info());
+
+/* Run the not-quit ACL, but without any custom messages. This should not be a
+problem, because we get here only if some other ACL has issued "drop", and
+in that case, *its* custom messages will have been used above. */
+
+smtp_notquit_exit(US"acl-drop", NULL, NULL);
return 2;
}
+/*************************************************
+* Handle SMTP exit when QUIT is not given *
+*************************************************/
+
+/* This function provides a logging/statistics hook for when an SMTP connection
+is dropped on the floor or the other end goes away. It's a global function
+because it's called from receive.c as well as this module. As well as running
+the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
+response, either with a custom message from the ACL, or using a default. There
+is one case, however, when no message is output - after "drop". In that case,
+the ACL that obeyed "drop" has already supplied the custom message, and NULL is
+passed to this function.
+
+In case things go wrong while processing this function, causing an error that
+may re-enter this funtion, there is a recursion check.
+
+Arguments:
+ reason What $smtp_notquit_reason will be set to in the ACL;
+ if NULL, the ACL is not run
+ code The error code to return as part of the response
+ defaultrespond The default message if there's no user_msg
+
+Returns: Nothing
+*/
+
+void
+smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
+{
+int rc;
+uschar *user_msg = NULL;
+uschar *log_msg = NULL;
+
+/* Check for recursive acll */
+
+if (smtp_exit_function_called)
+ {
+ log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
+ reason);
+ return;
+ }
+smtp_exit_function_called = TRUE;
+
+/* Call the not-QUIT ACL, if there is one, unless no reason is given. */
+
+if (acl_smtp_notquit != NULL && reason != NULL)
+ {
+ smtp_notquit_reason = reason;
+ rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
+ &log_msg);
+ if (rc == ERROR)
+ log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
+ log_msg);
+ }
+
+/* Write an SMTP response if we are expected to give one. As the default
+responses are all internal, they should always fit in the buffer, but code a
+warning, just in case. Note that string_vformat() still leaves a complete
+string, even if it is incomplete. */
+
+if (code != NULL && defaultrespond != NULL)
+ {
+ if (user_msg == NULL)
+ {
+ uschar buffer[128];
+ va_list ap;
+ va_start(ap, defaultrespond);
+ if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
+ log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
+ smtp_printf("%s %s\r\n", code, buffer);
+ va_end(ap);
+ }
+ else
+ smtp_respond(code, 3, TRUE, user_msg);
+ mac_smtp_fflush();
+ }
+}
+
+
+
+
/*************************************************
* Verify HELO argument *
*************************************************/
/* Find the name of the requested authentication mechanism. */
- s = smtp_cmd_argument;
- while ((c = *smtp_cmd_argument) != 0 && !isspace(c))
+ s = smtp_cmd_data;
+ while ((c = *smtp_cmd_data) != 0 && !isspace(c))
{
if (!isalnum(c) && c != '-' && c != '_')
{
US"invalid character in authentication mechanism name");
goto COMMAND_LOOP;
}
- smtp_cmd_argument++;
+ smtp_cmd_data++;
}
/* If not at the end of the line, we must be at white space. Terminate the
name and move the pointer on to any data that may be present. */
- if (*smtp_cmd_argument != 0)
+ if (*smtp_cmd_data != 0)
{
- *smtp_cmd_argument++ = 0;
- while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
+ *smtp_cmd_data++ = 0;
+ while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
}
/* Search for an authentication mechanism which is configured for use
expand_nmax = 0;
expand_nlength[0] = 0; /* $0 contains nothing */
- c = (au->info->servercode)(au, smtp_cmd_argument);
+ c = (au->info->servercode)(au, smtp_cmd_data);
if (au->set_id != NULL) set_id = expand_string(au->set_id);
expand_nmax = -1; /* Reset numeric variables */
for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
/* Reject the HELO if its argument was invalid or non-existent. A
successful check causes the argument to be saved in malloc store. */
- if (!check_helo(smtp_cmd_argument))
+ if (!check_helo(smtp_cmd_data))
{
smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
if (!sender_host_unknown)
{
BOOL old_helo_verified = helo_verified;
- uschar *p = smtp_cmd_argument;
+ uschar *p = smtp_cmd_data;
while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
*p = 0;
spf_init(sender_helo_name, sender_host_address);
#endif
- /* Apply an ACL check if one is defined */
+ /* Apply an ACL check if one is defined; afterwards, recheck
+ synchronization in case the client started sending in a delay. */
if (acl_smtp_helo != NULL)
{
host_build_sender_fullhost(); /* Rebuild */
break;
}
+ else if (!check_sync()) goto SYNC_FAILURE;
}
/* Generate an OK reply. The default string includes the ident if present,
/* Exim is quite happy with pipelining, so let the other end know that
it is safe to use it, unless advertising is disabled. */
- if (verify_check_host(&pipelining_advertise_hosts) == OK)
+ if (pipelining_enable &&
+ verify_check_host(&pipelining_advertise_hosts) == OK)
{
s = string_cat(s, &size, &ptr, smtp_code, 3);
s = string_cat(s, &size, &ptr, US"-PIPELINING\r\n", 13);
break;
}
- if (smtp_cmd_argument[0] == 0)
+ if (smtp_cmd_data[0] == 0)
{
done = synprot_error(L_smtp_protocol_error, 501, NULL,
US"MAIL must have an address operand");
in order to be able to log the sender address on failure. */
if (strcmpic(name, US"SIZE") == 0 &&
- ((size = (int)Ustrtoul(value, &end, 10)), *end == 0))
+ ((size = Ustrtoul(value, &end, 10)), *end == 0))
{
if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
size = INT_MAX;
TRUE flag allows "<>" as a sender address. */
raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
- rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
- global_rewrite_rules) : smtp_cmd_argument;
+ rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
+ global_rewrite_rules) : smtp_cmd_data;
/* rfc821_domains = TRUE; << no longer needed */
raw_sender =
if (raw_sender == NULL)
{
- done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
+ done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
break;
}
else
{
smtp_printf("501 %s: sender address must contain a domain\r\n",
- smtp_cmd_argument);
+ smtp_cmd_data);
log_write(L_smtp_syntax_error,
LOG_MAIN|LOG_REJECT,
"unqualified sender rejected: <%s> %s%s",
}
}
- /* Apply an ACL check if one is defined, before responding */
+ /* Apply an ACL check if one is defined, before responding. Afterwards,
+ when pipelining is not advertised, do another sync check in case the ACL
+ delayed and the client started sending in the meantime. */
- rc = (acl_smtp_mail == NULL)? OK :
- acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
+ if (acl_smtp_mail == NULL) rc = OK; else
+ {
+ rc = acl_check(ACL_WHERE_MAIL, NULL, acl_smtp_mail, &user_msg, &log_msg);
+ if (rc == OK && !pipelining_advertised && !check_sync())
+ goto SYNC_FAILURE;
+ }
if (rc == OK || rc == DISCARD)
{
break;
- /* The RCPT command requires an address as an operand. All we do
- here is to parse it for syntactic correctness. There may be any number
- of RCPT commands, specifying multiple senders. We build them all into
- a data structure that is in argc/argv format. The start/end values
- given by parse_extract_address are not used, as we keep only the
- extracted address. */
+ /* The RCPT command requires an address as an operand. There may be any
+ number of RCPT commands, specifying multiple recipients. We build them all
+ into a data structure. The start/end values given by parse_extract_address
+ are not used, as we keep only the extracted address. */
case RCPT_CMD:
HAD(SCH_RCPT);
rcpt_count++;
- was_rcpt = TRUE;
+ was_rcpt = rcpt_in_progress = TRUE;
/* There must be a sender address; if the sender was rejected and
pipelining was advertised, we assume the client was pipelining, and do not
/* Check for an operand */
- if (smtp_cmd_argument[0] == 0)
+ if (smtp_cmd_data[0] == 0)
{
done = synprot_error(L_smtp_syntax_error, 501, NULL,
US"RCPT must have an address operand");
as a recipient address */
recipient = ((rewrite_existflags & rewrite_smtp) != 0)?
- rewrite_one(smtp_cmd_argument, rewrite_smtp, NULL, FALSE, US"",
- global_rewrite_rules) : smtp_cmd_argument;
+ rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
+ global_rewrite_rules) : smtp_cmd_data;
/* rfc821_domains = TRUE; << no longer needed */
recipient = parse_extract_address(recipient, &errmess, &start, &end,
if (recipient == NULL)
{
- done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_argument, errmess);
+ done = synprot_error(L_smtp_syntax_error, 501, smtp_cmd_data, errmess);
rcpt_fail_count++;
break;
}
{
rcpt_fail_count++;
smtp_printf("501 %s: recipient address must contain a domain\r\n",
- smtp_cmd_argument);
+ smtp_cmd_data);
log_write(L_smtp_syntax_error,
LOG_MAIN|LOG_REJECT, "unqualified recipient rejected: "
"<%s> %s%s", recipient, host_and_ident(TRUE),
}
/* If the MAIL ACL discarded all the recipients, we bypass ACL checking
- for them. Otherwise, check the access control list for this recipient. */
+ for them. Otherwise, check the access control list for this recipient. As
+ there may be a delay in this, re-check for a synchronization error
+ afterwards, unless pipelining was advertised. */
- rc = recipients_discarded? DISCARD :
- acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg, &log_msg);
+ if (recipients_discarded) rc = DISCARD; else
+ {
+ rc = acl_check(ACL_WHERE_RCPT, recipient, acl_smtp_rcpt, &user_msg,
+ &log_msg);
+ if (rc == OK && !pipelining_advertised && !check_sync())
+ goto SYNC_FAILURE;
+ }
/* The ACL was happy */
DATA command.
The example in the pipelining RFC 2920 uses 554, but I use 503 here
- because it is the same whether pipelining is in use or not. */
+ because it is the same whether pipelining is in use or not.
+
+ If all the RCPT commands that precede DATA provoked the same error message
+ (often indicating some kind of system error), it is helpful to include it
+ with the DATA rejection (an idea suggested by Tony Finch). */
case DATA_CMD:
HAD(SCH_DATA);
if (!discarded && recipients_count <= 0)
{
+ if (rcpt_smtp_response_same && rcpt_smtp_response != NULL)
+ {
+ uschar *code = US"503";
+ int len = Ustrlen(rcpt_smtp_response);
+ smtp_respond(code, 3, FALSE, US"All RCPT commands were rejected with "
+ "this error:");
+ /* Responses from smtp_printf() will have \r\n on the end */
+ if (len > 2 && rcpt_smtp_response[len-2] == '\r')
+ rcpt_smtp_response[len-2] = 0;
+ smtp_respond(code, 3, FALSE, rcpt_smtp_response);
+ }
if (pipelining_advertised && last_was_rcpt)
- smtp_printf("503 valid RCPT command must precede DATA\r\n");
+ smtp_printf("503 Valid RCPT command must precede DATA\r\n");
else
done = synprot_error(L_smtp_protocol_error, 503, NULL,
US"valid RCPT command must precede DATA");
break;
}
+ /* If there is an ACL, re-check the synchronization afterwards, since the
+ ACL may have delayed. */
+
if (acl_smtp_predata == NULL) rc = OK; else
{
enable_dollar_recipients = TRUE;
rc = acl_check(ACL_WHERE_PREDATA, NULL, acl_smtp_predata, &user_msg,
&log_msg);
enable_dollar_recipients = FALSE;
+ if (rc == OK && !check_sync()) goto SYNC_FAILURE;
}
if (rc == OK)
else
done = smtp_handle_acl_fail(ACL_WHERE_PREDATA, rc, user_msg, log_msg);
-
break;
uschar *s = NULL;
/* rfc821_domains = TRUE; << no longer needed */
- address = parse_extract_address(smtp_cmd_argument, &errmess, &start, &end,
+ address = parse_extract_address(smtp_cmd_data, &errmess, &start, &end,
&recipient_domain, FALSE);
/* rfc821_domains = FALSE; << no longer needed */
{
BOOL save_log_testing_mode = log_testing_mode;
address_test_mode = log_testing_mode = TRUE;
- (void) verify_address(deliver_make_addr(smtp_cmd_argument, FALSE),
+ (void) verify_address(deliver_make_addr(smtp_cmd_data, FALSE),
smtp_out, vopt_is_recipient | vopt_qualify | vopt_expn, -1, -1, -1,
NULL, NULL, NULL);
address_test_mode = FALSE;
toomany = FALSE;
cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = FALSE;
+ /* There's an attack where more data is read in past the STARTTLS command
+ before TLS is negotiated, then assumed to be part of the secure session
+ when used afterwards; we use segregated input buffers, so are not
+ vulnerable, but we want to note when it happens and, for sheer paranoia,
+ ensure that the buffer is "wiped".
+ Pipelining sync checks will normally have protected us too, unless disabled
+ by configuration. */
+
+ if (receive_smtp_buffered())
+ {
+ DEBUG(D_any)
+ debug_printf("Non-empty input buffer after STARTTLS; naive attack?");
+ if (tls_active < 0)
+ smtp_inend = smtp_inptr = smtp_inbuffer;
+ /* and if TLS is already active, tls_server_start() should fail */
+ }
+
+ /* There is nothing we value in the input buffer and if TLS is succesfully
+ negotiated, we won't use this buffer again; if TLS fails, we'll just read
+ fresh content into it. The buffer contains arbitrary content from an
+ untrusted remote source; eg: NOOP <shellcode>\r\nSTARTTLS\r\n
+ It seems safest to just wipe away the content rather than leave it as a
+ target to jump to. */
+
+ memset(smtp_inbuffer, 0, in_buffer_size);
+
/* Attempt to start up a TLS session, and if successful, discard all
knowledge that was obtained previously. At least, that's what the RFC says,
and that's what happens by default. However, in order to work round YAEB,
We must allow for an extra EHLO command and an extra AUTH command after
STARTTLS that don't add to the nonmail command count. */
- if ((rc = tls_server_start(tls_require_ciphers)) == OK)
+ if ((rc = tls_server_start(tls_require_ciphers, gnutls_require_mac,
+ gnutls_require_kx, gnutls_require_proto)) == OK)
{
if (!tls_remember_esmtp)
helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
case EOF_CMD:
log_write(L_smtp_connection, LOG_MAIN, "%s closed by EOF",
smtp_get_connection_info());
+ smtp_notquit_exit(US"tls-failed", NULL, NULL);
done = 2;
break;
+ /* It is perhaps arguable as to which exit ACL should be called here,
+ but as it is probably a situtation that almost never arises, it
+ probably doesn't matter. We choose to call the real QUIT ACL, which in
+ some sense is perhaps "right". */
+
case QUIT_CMD:
- smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
+ user_msg = NULL;
+ if (acl_smtp_quit != NULL)
+ {
+ rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg,
+ &log_msg);
+ if (rc == ERROR)
+ log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
+ log_msg);
+ }
+ if (user_msg == NULL)
+ smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
+ else
+ smtp_respond(US"221", 3, TRUE, user_msg);
log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
smtp_get_connection_info());
done = 2;
case QUIT_CMD:
HAD(SCH_QUIT);
incomplete_transaction_log(US"QUIT");
-
if (acl_smtp_quit != NULL)
{
- rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit,&user_msg,&log_msg);
+ rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, &user_msg, &log_msg);
if (rc == ERROR)
log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
log_msg);
}
-
if (user_msg == NULL)
smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
else
break;
- /* Show ETRN/EXPN/VRFY if there's
- an ACL for checking hosts; if actually used, a check will be done for
- permitted hosts. */
+ /* Show ETRN/EXPN/VRFY if there's an ACL for checking hosts; if actually
+ used, a check will be done for permitted hosts. Show STARTTLS only if not
+ already in a TLS session and if it would be advertised in the EHLO
+ response. */
case HELP_CMD:
HAD(SCH_HELP);
buffer[0] = 0;
Ustrcat(buffer, " AUTH");
#ifdef SUPPORT_TLS
- Ustrcat(buffer, " STARTTLS");
+ if (tls_active < 0 &&
+ verify_check_host(&tls_advertise_hosts) != FAIL)
+ Ustrcat(buffer, " STARTTLS");
#endif
Ustrcat(buffer, " HELO EHLO MAIL RCPT DATA");
Ustrcat(buffer, " NOOP QUIT RSET HELP");
case EOF_CMD:
incomplete_transaction_log(US"connection lost");
- smtp_printf("421 %s lost input connection\r\n", smtp_active_hostname);
+ smtp_notquit_exit(US"connection-lost", US"421",
+ US"%s lost input connection", smtp_active_hostname);
/* Don't log by default unless in the middle of a message, as some mailers
just drop the call rather than sending QUIT, and it clutters up the logs.
/* Compute the serialization key for this command. */
- etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_argument);
+ etrn_serialize_key = string_sprintf("etrn-%s\n", smtp_cmd_data);
/* If a command has been specified for running as a result of ETRN, we
permit any argument to ETRN. If not, only the # standard form is permitted,
uschar *error;
BOOL rc;
etrn_command = smtp_etrn_command;
- deliver_domain = smtp_cmd_argument;
+ deliver_domain = smtp_cmd_data;
rc = transport_set_up_command(&argv, smtp_etrn_command, TRUE, 0, NULL,
US"ETRN processing", &error);
deliver_domain = NULL;
else
{
- if (*smtp_cmd_argument++ != '#')
+ if (*smtp_cmd_data++ != '#')
{
done = synprot_error(L_smtp_syntax_error, 501, NULL,
US"argument must begin with #");
}
etrn_command = US"exim -R";
argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, NULL, TRUE, 2, US"-R",
- smtp_cmd_argument);
+ smtp_cmd_data);
}
/* If we are host-testing, don't actually do anything. */
if (smtp_etrn_serialize && !enq_start(etrn_serialize_key))
{
- smtp_printf("458 Already processing %s\r\n", smtp_cmd_argument);
+ smtp_printf("458 Already processing %s\r\n", smtp_cmd_data);
break;
}
case BADSYN_CMD:
+ SYNC_FAILURE:
if (smtp_inend >= smtp_inbuffer + in_buffer_size)
smtp_inend = smtp_inbuffer + in_buffer_size - 1;
c = smtp_inend - smtp_inptr;
pipelining_advertised? "" : " not",
smtp_cmd_buffer, host_and_ident(TRUE),
string_printing(smtp_inptr));
- smtp_printf("554 SMTP synchronization error\r\n");
+ smtp_notquit_exit(US"synchronization-error", US"554",
+ US"SMTP synchronization error");
done = 1; /* Pretend eof - drops connection */
break;
case TOO_MANY_NONMAIL_CMD:
+ s = smtp_cmd_buffer;
+ while (*s != 0 && !isspace(*s)) s++;
incomplete_transaction_log(US"too many non-mail commands");
log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
"nonmail commands (last was \"%.*s\")", host_and_ident(FALSE),
- smtp_cmd_argument - smtp_cmd_buffer, smtp_cmd_buffer);
- smtp_printf("554 Too many nonmail commands\r\n");
+ s - smtp_cmd_buffer, smtp_cmd_buffer);
+ smtp_notquit_exit(US"bad-commands", US"554", US"Too many nonmail commands");
done = 1; /* Pretend eof - drops connection */
break;
string_printing(smtp_cmd_buffer), host_and_ident(TRUE),
US"unrecognized command");
incomplete_transaction_log(US"unrecognized command");
- smtp_printf("500 Too many unrecognized commands\r\n");
+ smtp_notquit_exit(US"bad-commands", US"500",
+ US"Too many unrecognized commands");
done = 2;
log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
"unrecognized commands (last was \"%s\")", host_and_ident(FALSE),
git://git.exim.org / exim.git / blobdiff