-/* $Cambridge: exim/src/src/smtp_in.c,v 1.67 2010/06/12 15:21:26 jetmore Exp $ */
-
/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2009 */
+/* Copyright (c) University of Cambridge 1995 - 2012 */
/* See the file NOTICE for conditions of use and distribution. */
/* Functions for handling an incoming SMTP call. */
/* 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;
#define pauthed 2 /* added to pextend */
#define pnlocal 6 /* offset to remove "local" */
+/* Sanity check and validate optional args to MAIL FROM: envelope */
+enum {
+ ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
+ ENV_MAIL_OPT_PRDR, ENV_MAIL_OPT_NULL
+ };
+typedef struct {
+ uschar * name; /* option requested during MAIL cmd */
+ int value; /* enum type */
+ BOOL need_value; /* TRUE requires value (name=value pair format)
+ FALSE is a singleton */
+ } env_mail_type_t;
+static env_mail_type_t env_mail_type_list[] = {
+ { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
+ { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
+ { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
+ { US"NULL", ENV_MAIL_OPT_NULL, FALSE } /* Placeholder for ending */
+ };
+
/* When reading SMTP from a remote host, we have to use our own versions of the
C input-reading functions, in order to be able to flush the SMTP output only
when about to read more data from the socket. This is the only way to get
*/
void
-smtp_printf(char *format, ...)
+smtp_printf(const char *format, ...)
{
va_list 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.
-
-Note also that repeated calls to va_start()/va_end() pairs is claimed to be
-non-portable; meanwhile, va_copy() is also non-portable in that it's C99, so
-we end up needing OS support to define it for us. */
+call another vararg function, only a function which accepts a va_list. */
void
-smtp_vprintf(char *format, va_list ap)
+smtp_vprintf(const char *format, va_list ap)
{
-va_list ap_d;
+BOOL yield;
+
+yield = string_vformat(big_buffer, big_buffer_size, format, ap);
DEBUG(D_receive)
{
- uschar *cr, *end;
- va_copy(ap_d, ap);
- (void) string_vformat(big_buffer, big_buffer_size, format, ap_d);
- 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);
}
-if (!string_vformat(big_buffer, big_buffer_size, format, ap))
+if (!yield)
{
log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
smtp_closedown(US"Unexpected error");
if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_peerdn != NULL)
s = string_append(s, &size, &ptr, 3, US" DN=\"",
string_printing(tls_peerdn), US"\"");
+if ((log_extra_selector & LX_tls_sni) != 0 && tls_sni != NULL)
+ s = string_append(s, &size, &ptr, 3, US" SNI=\"",
+ string_printing(tls_sni), US"\"");
#endif
sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
n = v;
while(isalpha(n[-1])) n--;
-if (n[-1] != ' ') return FALSE;
+/* RFC says SP, but TAB seen in wild and other major MTAs accept it */
+if (!isspace(n[-1])) return FALSE;
n[-1] = 0;
*name = n;
recipients_list = NULL;
rcpt_count = rcpt_defer_count = rcpt_fail_count =
raw_recipients_count = recipients_count = recipients_list_max = 0;
+cancel_cutthrough_connection();
message_linecount = 0;
message_size = -1;
acl_added_headers = NULL;
no_mbox_unspool = FALSE; /* Can be set by ACL */
#endif
submission_mode = FALSE; /* Can be set by ACL */
-suppress_local_fixups = FALSE; /* Can be set by ACL */
+suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
active_local_from_check = local_from_check; /* Can be set by ACL */
active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
sender_address = NULL;
if (smtp_cmd_buffer == NULL)
log_write(0, LOG_MAIN|LOG_PANIC_DIE,
"malloc() failed for SMTP command buffer");
+smtp_cmd_buffer[0] = 0;
smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
/* For batched input, the protocol setting can be overridden from the
#ifdef SUPPORT_TLS
if (tls_on_connect &&
- tls_server_start(tls_require_ciphers,
- gnutls_require_mac, gnutls_require_kx, gnutls_require_proto) != OK)
+ tls_server_start(tls_require_ciphers) != OK)
return FALSE;
#endif
if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
#endif
{
- sender_info = string_sprintf("F=<%s> ", (sender_address_unrewritten != NULL)?
- sender_address_unrewritten : sender_address);
+ sender_info = string_sprintf("F=<%s>%s%s%s%s ",
+ sender_address_unrewritten ? sender_address_unrewritten : sender_address,
+ sender_host_authenticated ? US" A=" : US"",
+ sender_host_authenticated ? sender_host_authenticated : US"",
+ sender_host_authenticated && authenticated_id ? US":" : US"",
+ sender_host_authenticated && authenticated_id ? authenticated_id : US""
+ );
}
/* If there's been a sender verification failure with a specific message, and
HAD(SCH_MAIL);
smtp_mailcmd_count++; /* Count for limit and ratelimit */
was_rej_mail = TRUE; /* Reset if accepted */
+ env_mail_type_t * mail_args; /* Sanity check & validate args */
if (helo_required && !helo_seen)
{
{
uschar *name, *value, *end;
unsigned long int size;
+ BOOL arg_error = FALSE;
if (!extract_option(&name, &value)) break;
- /* Handle SIZE= by reading the value. We don't do the check till later,
- in order to be able to log the sender address on failure. */
-
- if (strcmpic(name, US"SIZE") == 0 &&
- ((size = Ustrtoul(value, &end, 10)), *end == 0))
+ for (mail_args = env_mail_type_list;
+ (char *)mail_args < (char *)env_mail_type_list + sizeof(env_mail_type_list);
+ mail_args++
+ )
{
- if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
- size = INT_MAX;
- message_size = (int)size;
+ if (strcmpic(name, mail_args->name) == 0)
+ break;
}
+ if (mail_args->need_value && strcmpic(value, US"") == 0)
+ break;
+ /* This doesn't seem right to use
+ if ((char *)mail_args >= (char *)env_mail_type_list + sizeof(env_mail_type_list))
+ goto BAD_MAIL_ARGS;
+ */
- /* If this session was initiated with EHLO and accept_8bitmime is set,
- Exim will have indicated that it supports the BODY=8BITMIME option. In
- fact, it does not support this according to the RFCs, in that it does not
- take any special action for forwarding messages containing 8-bit
- characters. That is why accept_8bitmime is not the default setting, but
- some sites want the action that is provided. We recognize both "8BITMIME"
- and "7BIT" as body types, but take no action. */
-
- else if (accept_8bitmime && strcmpic(name, US"BODY") == 0 &&
- (strcmpic(value, US"8BITMIME") == 0 ||
- strcmpic(value, US"7BIT") == 0)) {}
-
- /* Handle the AUTH extension. If the value given is not "<>" and either
- the ACL says "yes" or there is no ACL but the sending host is
- authenticated, we set it up as the authenticated sender. However, if the
- authenticator set a condition to be tested, we ignore AUTH on MAIL unless
- the condition is met. The value of AUTH is an xtext, which means that +,
- = and cntrl chars are coded in hex; however "<>" is unaffected by this
- coding. */
-
- else if (strcmpic(name, US"AUTH") == 0)
+ switch(mail_args->value)
{
- if (Ustrcmp(value, "<>") != 0)
- {
- int rc;
- uschar *ignore_msg;
-
- if (auth_xtextdecode(value, &authenticated_sender) < 0)
- {
- /* Put back terminator overrides for error message */
- name[-1] = ' ';
- value[-1] = '=';
- done = synprot_error(L_smtp_syntax_error, 501, NULL,
- US"invalid data for AUTH");
- goto COMMAND_LOOP;
- }
-
- if (acl_smtp_mailauth == NULL)
+ /* Handle SIZE= by reading the value. We don't do the check till later,
+ in order to be able to log the sender address on failure. */
+ case ENV_MAIL_OPT_SIZE:
+ /* if (strcmpic(name, US"SIZE") == 0 && */
+ if (((size = Ustrtoul(value, &end, 10)), *end == 0))
{
- ignore_msg = US"client not authenticated";
- rc = (sender_host_authenticated != NULL)? OK : FAIL;
+ if ((size == ULONG_MAX && errno == ERANGE) || size > INT_MAX)
+ size = INT_MAX;
+ message_size = (int)size;
}
else
- {
- ignore_msg = US"rejected by ACL";
- rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
- &user_msg, &log_msg);
- }
+ arg_error = TRUE;
+ break;
- switch (rc)
- {
- case OK:
- if (authenticated_by == NULL ||
- authenticated_by->mail_auth_condition == NULL ||
- expand_check_condition(authenticated_by->mail_auth_condition,
- authenticated_by->name, US"authenticator"))
- break; /* Accept the AUTH */
-
- ignore_msg = US"server_mail_auth_condition failed";
- if (authenticated_id != NULL)
- ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
- ignore_msg, authenticated_id);
-
- /* Fall through */
-
- case FAIL:
- authenticated_sender = NULL;
- log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
- value, host_and_ident(TRUE), ignore_msg);
+ /* If this session was initiated with EHLO and accept_8bitmime is set,
+ Exim will have indicated that it supports the BODY=8BITMIME option. In
+ fact, it does not support this according to the RFCs, in that it does not
+ take any special action for forwarding messages containing 8-bit
+ characters. That is why accept_8bitmime is not the default setting, but
+ some sites want the action that is provided. We recognize both "8BITMIME"
+ and "7BIT" as body types, but take no action. */
+ case ENV_MAIL_OPT_BODY:
+ if (accept_8bitmime &&
+ (strcmpic(value, US"8BITMIME") == 0 ||
+ strcmpic(value, US"7BIT") == 0) )
break;
+ arg_error = TRUE;
+ break;
- /* Should only get DEFER or ERROR here. Put back terminator
- overrides for error message */
+ /* Handle the AUTH extension. If the value given is not "<>" and either
+ the ACL says "yes" or there is no ACL but the sending host is
+ authenticated, we set it up as the authenticated sender. However, if the
+ authenticator set a condition to be tested, we ignore AUTH on MAIL unless
+ the condition is met. The value of AUTH is an xtext, which means that +,
+ = and cntrl chars are coded in hex; however "<>" is unaffected by this
+ coding. */
+ case ENV_MAIL_OPT_AUTH:
+ if (Ustrcmp(value, "<>") != 0)
+ {
+ int rc;
+ uschar *ignore_msg;
- default:
- name[-1] = ' ';
- value[-1] = '=';
- (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
- log_msg);
- goto COMMAND_LOOP;
+ if (auth_xtextdecode(value, &authenticated_sender) < 0)
+ {
+ /* Put back terminator overrides for error message */
+ name[-1] = ' ';
+ value[-1] = '=';
+ done = synprot_error(L_smtp_syntax_error, 501, NULL,
+ US"invalid data for AUTH");
+ goto COMMAND_LOOP;
+ }
+ if (acl_smtp_mailauth == NULL)
+ {
+ ignore_msg = US"client not authenticated";
+ rc = (sender_host_authenticated != NULL)? OK : FAIL;
+ }
+ else
+ {
+ ignore_msg = US"rejected by ACL";
+ rc = acl_check(ACL_WHERE_MAILAUTH, NULL, acl_smtp_mailauth,
+ &user_msg, &log_msg);
+ }
+
+ switch (rc)
+ {
+ case OK:
+ if (authenticated_by == NULL ||
+ authenticated_by->mail_auth_condition == NULL ||
+ expand_check_condition(authenticated_by->mail_auth_condition,
+ authenticated_by->name, US"authenticator"))
+ break; /* Accept the AUTH */
+
+ ignore_msg = US"server_mail_auth_condition failed";
+ if (authenticated_id != NULL)
+ ignore_msg = string_sprintf("%s: authenticated ID=\"%s\"",
+ ignore_msg, authenticated_id);
+
+ /* Fall through */
+
+ case FAIL:
+ authenticated_sender = NULL;
+ log_write(0, LOG_MAIN, "ignoring AUTH=%s from %s (%s)",
+ value, host_and_ident(TRUE), ignore_msg);
+ break;
+
+ /* Should only get DEFER or ERROR here. Put back terminator
+ overrides for error message */
+
+ default:
+ name[-1] = ' ';
+ value[-1] = '=';
+ (void)smtp_handle_acl_fail(ACL_WHERE_MAILAUTH, rc, user_msg,
+ log_msg);
+ goto COMMAND_LOOP;
+ }
}
- }
- }
-
- /* Unknown option. Stick back the terminator characters and break
- the loop. An error for a malformed address will occur. */
+ break;
+
+ /* Unknown option. Stick back the terminator characters and break
+ the loop. An error for a malformed address will occur. */
+ default:
- else
- {
- name[-1] = ' ';
- value[-1] = '=';
- break;
+ /* BAD_MAIL_ARGS: */
+ name[-1] = ' ';
+ value[-1] = '=';
+ break;
}
+ /* Break out of for loop if switch() had bad argument or
+ when start of the email address is reached */
+ if (arg_error) break;
}
/* If we have passed the threshold for rate limiting, apply the current
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, gnutls_require_mac,
- gnutls_require_kx, gnutls_require_proto)) == OK)
+ if ((rc = tls_server_start(tls_require_ciphers)) == OK)
{
if (!tls_remember_esmtp)
helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE;
projects / exim.git / blobdiff