-/* $Cambridge: exim/src/src/smtp_in.c,v 1.54 2007/02/20 11:37:16 ph10 Exp $ */
+/* $Cambridge: exim/src/src/smtp_in.c,v 1.57 2007/04/13 15:13:47 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
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 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;
+/*************************************************
+* 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 *
}
va_start(ap, format);
+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);
+ }
+va_end(ap);
-/* If in a TLS session we have to format the string, and then write it using a
-TLS function. */
+/* 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 (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;
}
+
/*************************************************
* Read one command line *
*************************************************/
+/*************************************************
+* 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 *
*************************************************/
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 */
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;
/* 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');
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 */
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,
}
}
- /* 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
}
/* 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;
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;
projects / user / henk / code / exim.git / blobdiff