/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
-/* Experimental DMARC support.
+/* DMARC support.
Copyright (c) Todd Lyons <tlyons@exim.org> 2012 - 2014
+ Copyright (c) The Exim Maintainers 2019
License: GPL */
/* Portions Copyright (c) 2012, 2013, The Trusted Domain Project;
/* Code for calling dmarc checks via libopendmarc. Called from acl.c. */
#include "exim.h"
-#ifdef EXPERIMENTAL_DMARC
-# if !defined EXPERIMENTAL_SPF
+#ifdef SUPPORT_DMARC
+# if !defined SUPPORT_SPF
# error SPF must also be enabled for DMARC
# elif defined DISABLE_DKIM
# error DKIM must also be enabled for DMARC
OPENDMARC_STATUS_T da, sa, action;
BOOL dmarc_abort = FALSE;
uschar *dmarc_pass_fail = US"skipped";
-extern pdkim_signature *dkim_signatures;
header_line *from_header = NULL;
extern SPF_response_t *spf_response;
int dmarc_spf_ares_result = 0;
} dmarc_exim_p;
static dmarc_exim_p dmarc_policy_description[] = {
+ /* name value */
{ US"", DMARC_RECORD_P_UNSPECIFIED },
{ US"none", DMARC_RECORD_P_NONE },
{ US"quarantine", DMARC_RECORD_P_QUARANTINE },
messages on the same SMTP connection (that come from the
same host with the same HELO string) */
-int dmarc_init()
+int
+dmarc_init()
{
int *netmask = NULL; /* Ignored */
int is_ipv6 = 0;
-char *tld_file = (dmarc_tld_file == NULL) ?
- DMARC_TLD_FILE : (char *)dmarc_tld_file;
/* Set some sane defaults. Also clears previous results when
* multiple messages in one connection. */
dmarc_abort = FALSE;
dmarc_pass_fail = US"skipped";
dmarc_used_domain = US"";
-dmarc_ar_header = NULL;
-dmarc_has_been_checked = FALSE;
+f.dmarc_has_been_checked = FALSE;
header_from_sender = NULL;
spf_sender_domain = NULL;
spf_human_readable = NULL;
/* ACLs have "control=dmarc_disable_verify" */
-if (dmarc_disable_verify == TRUE)
+if (f.dmarc_disable_verify == TRUE)
return OK;
(void) memset(&dmarc_ctx, '\0', sizeof dmarc_ctx);
opendmarc_policy_status_to_str(libdm_status));
dmarc_abort = TRUE;
}
-if (dmarc_tld_file == NULL)
+if (!dmarc_tld_file || !*dmarc_tld_file)
+ {
+ DEBUG(D_receive) debug_printf("DMARC: no dmarc_tld_file\n");
dmarc_abort = TRUE;
-else if (opendmarc_tld_read_file(tld_file, NULL, NULL, NULL))
+ }
+else if (opendmarc_tld_read_file(CS dmarc_tld_file, NULL, NULL, NULL))
{
- log_write(0, LOG_MAIN|LOG_PANIC, "DMARC failure to load tld list %s: %d",
- tld_file, errno);
+ log_write(0, LOG_MAIN|LOG_PANIC, "DMARC failure to load tld list '%s': %s",
+ dmarc_tld_file, strerror(errno));
dmarc_abort = TRUE;
}
-if (sender_host_address == NULL)
+if (!sender_host_address)
+ {
+ DEBUG(D_receive) debug_printf("DMARC: no sender_host_address\n");
dmarc_abort = TRUE;
+ }
/* This catches locally originated email and startup errors above. */
if (!dmarc_abort)
{
is_ipv6 = string_is_ip_address(sender_host_address, netmask) == 6;
- dmarc_pctx = opendmarc_policy_connect_init(sender_host_address, is_ipv6);
- if (dmarc_pctx == NULL)
+ if (!(dmarc_pctx = opendmarc_policy_connect_init(sender_host_address, is_ipv6)))
{
log_write(0, LOG_MAIN|LOG_PANIC,
"DMARC failure creating policy context: ip=%s", sender_host_address);
/* dmarc_store_data stores the header data so that subsequent
- * dmarc_process can access the data */
+dmarc_process can access the data */
-int dmarc_store_data(header_line *hdr) {
- /* No debug output because would change every test debug output */
- if (dmarc_disable_verify != TRUE)
- from_header = hdr;
- return OK;
+int
+dmarc_store_data(header_line *hdr)
+{
+/* No debug output because would change every test debug output */
+if (!f.dmarc_disable_verify)
+ from_header = hdr;
+return OK;
}
static void
dmarc_send_forensic_report(u_char **ruf)
{
-int c;
uschar *recipient, *save_sender;
BOOL send_status = FALSE;
error_block *eblock = NULL;
FILE *message_file = NULL;
/* Earlier ACL does not have *required* control=dmarc_enable_forensic */
-if (!dmarc_enable_forensic)
+if (!f.dmarc_enable_forensic)
return;
if ( dmarc_policy == DMARC_POLICY_REJECT && action == DMARC_RESULT_REJECT
eblock = add_to_eblock(eblock, US"Sender IP Address", sender_host_address);
eblock = add_to_eblock(eblock, US"Received Date", tod_stamp(tod_full));
eblock = add_to_eblock(eblock, US"SPF Alignment",
- (sa==DMARC_POLICY_SPF_ALIGNMENT_PASS) ?US"yes":US"no");
+ sa == DMARC_POLICY_SPF_ALIGNMENT_PASS ? US"yes" : US"no");
eblock = add_to_eblock(eblock, US"DKIM Alignment",
- (da==DMARC_POLICY_DKIM_ALIGNMENT_PASS)?US"yes":US"no");
+ da == DMARC_POLICY_DKIM_ALIGNMENT_PASS ? US"yes" : US"no");
eblock = add_to_eblock(eblock, US"DMARC Results", dmarc_status_text);
- /* Set a sane default envelope sender */
- dsn_from = dmarc_forensic_sender ? dmarc_forensic_sender :
- dsn_from ? dsn_from :
- string_sprintf("do-not-reply@%s",primary_hostname);
- for (c = 0; ruf[c]; c++)
+
+ for (int c = 0; ruf[c]; c++)
{
recipient = string_copylc(ruf[c]);
if (Ustrncmp(recipient, "mailto:",7))
recipient += 7;
DEBUG(D_receive)
debug_printf("DMARC forensic report to %s%s\n", recipient,
- (host_checking || running_in_test_harness) ? " (not really)" : "");
- if (host_checking || running_in_test_harness)
+ (host_checking || f.running_in_test_harness) ? " (not really)" : "");
+ if (host_checking || f.running_in_test_harness)
continue;
- save_sender = sender_address;
- sender_address = recipient;
- send_status = moan_to_sender(ERRMESS_DMARC_FORENSIC, eblock,
- header_list, message_file, FALSE);
- sender_address = save_sender;
- if (!send_status)
+ if (!moan_send_message(recipient, ERRMESS_DMARC_FORENSIC, eblock,
+ header_list, message_file, NULL))
log_write(0, LOG_MAIN|LOG_PANIC,
"failure to send DMARC forensic report to %s", recipient);
}
}
}
+
+/* Look up a DNS dmarc record for the given domain. Return it or NULL */
+
+static uschar *
+dmarc_dns_lookup(uschar * dom)
+{
+dns_answer * dnsa = store_get_dns_answer();
+dns_scan dnss;
+int rc = dns_lookup(dnsa, string_sprintf("_dmarc.%s", dom), T_TXT, NULL);
+
+if (rc == DNS_SUCCEED)
+ for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
+ rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
+ if (rr->type == T_TXT && rr->size > 3)
+ return string_copyn(US rr->data, rr->size);
+return NULL;
+}
+
+
/* dmarc_process adds the envelope sender address to the existing
- context (if any), retrieves the result, sets up expansion
- strings and evaluates the condition outcome. */
+context (if any), retrieves the result, sets up expansion
+strings and evaluates the condition outcome. */
int
dmarc_process()
int sr, origin; /* used in SPF section */
int dmarc_spf_result = 0; /* stores spf into dmarc conn ctx */
int tmp_ans, c;
-pdkim_signature *sig = NULL;
+pdkim_signature * sig = dkim_signatures;
+uschar * rr;
BOOL has_dmarc_record = TRUE;
u_char **ruf; /* forensic report addressees, if called for */
/* ACLs have "control=dmarc_disable_verify" */
-if (dmarc_disable_verify)
- {
- dmarc_ar_header = dmarc_auth_results_header(from_header, NULL);
+if (f.dmarc_disable_verify)
return OK;
- }
/* Store the header From: sender domain for this part of DMARC.
* If there is no from_header struct, then it's likely this message
* the entire DMARC system if we can't find a From: header....or if
* there was a previous error.
*/
-if (!from_header || dmarc_abort)
+if (!from_header)
+ {
+ DEBUG(D_receive) debug_printf("DMARC: no From: header\n");
dmarc_abort = TRUE;
-else
+ }
+else if (!dmarc_abort)
{
- uschar * errormsg;
- int dummy, domain;
- uschar * p;
- uschar saveend;
-
- parse_allow_group = TRUE;
- p = parse_find_address_end(from_header->text, FALSE);
- saveend = *p; *p = '\0';
- if ((header_from_sender = parse_extract_address(from_header->text, &errormsg,
- &dummy, &dummy, &domain, FALSE)))
- header_from_sender += domain;
- *p = saveend;
-
- /* The opendmarc library extracts the domain from the email address, but
- * only try to store it if it's not empty. Otherwise, skip out of DMARC. */
- if (!header_from_sender || (strcmp( CCS header_from_sender, "") == 0))
- dmarc_abort = TRUE;
- libdm_status = dmarc_abort ?
- DMARC_PARSE_OKAY :
- opendmarc_policy_store_from_domain(dmarc_pctx, header_from_sender);
- if (libdm_status != DMARC_PARSE_OKAY)
+ uschar * errormsg;
+ int dummy, domain;
+ uschar * p;
+ uschar saveend;
+
+ f.parse_allow_group = TRUE;
+ p = parse_find_address_end(from_header->text, FALSE);
+ saveend = *p; *p = '\0';
+ if ((header_from_sender = parse_extract_address(from_header->text, &errormsg,
+ &dummy, &dummy, &domain, FALSE)))
+ header_from_sender += domain;
+ *p = saveend;
+
+ /* The opendmarc library extracts the domain from the email address, but
+ * only try to store it if it's not empty. Otherwise, skip out of DMARC. */
+ if (!header_from_sender || (strcmp( CCS header_from_sender, "") == 0))
+ dmarc_abort = TRUE;
+ libdm_status = dmarc_abort
+ ? DMARC_PARSE_OKAY
+ : opendmarc_policy_store_from_domain(dmarc_pctx, header_from_sender);
+ if (libdm_status != DMARC_PARSE_OKAY)
{
log_write(0, LOG_MAIN|LOG_PANIC,
"failure to store header From: in DMARC: %s, header was '%s'",
* instead do this in the ACLs. */
if (!dmarc_abort && !sender_host_authenticated)
{
+ uschar * dmarc_domain;
+
/* Use the envelope sender domain for this part of DMARC */
spf_sender_domain = expand_string(US"$sender_address_domain");
if (!spf_response)
sr == SPF_RESULT_PERMERROR ? ARES_RESULT_PERMERROR :
ARES_RESULT_UNKNOWN;
origin = DMARC_POLICY_SPF_ORIGIN_MAILFROM;
- spf_human_readable = (uschar *)spf_response->header_comment;
+ spf_human_readable = US spf_response->header_comment;
DEBUG(D_receive)
debug_printf("DMARC using SPF sender domain = %s\n", spf_sender_domain);
}
/* Now we cycle through the dkim signature results and put into
* the opendmarc context, further building the DMARC reply. */
- sig = dkim_signatures;
dkim_history_buffer = US"";
while (sig)
{
int dkim_result, dkim_ares_result, vs, ves;
- vs = sig->verify_status;
+
+ vs = sig->verify_status & ~PDKIM_VERIFY_POLICY;
ves = sig->verify_ext_status;
dkim_result = vs == PDKIM_VERIFY_PASS ? DMARC_POLICY_DKIM_OUTCOME_PASS :
vs == PDKIM_VERIFY_FAIL ? DMARC_POLICY_DKIM_OUTCOME_FAIL :
vs == PDKIM_VERIFY_INVALID ? DMARC_POLICY_DKIM_OUTCOME_TMPFAIL :
DMARC_POLICY_DKIM_OUTCOME_NONE;
- libdm_status = opendmarc_policy_store_dkim(dmarc_pctx, (uschar *)sig->domain,
+ libdm_status = opendmarc_policy_store_dkim(dmarc_pctx, US sig->domain,
dkim_result, US"");
DEBUG(D_receive)
debug_printf("DMARC adding DKIM sender domain = %s\n", sig->domain);
sig->domain, dkim_ares_result);
sig = sig->next;
}
- libdm_status = opendmarc_policy_query_dmarc(dmarc_pctx, US"");
+
+ /* Look up DMARC policy record in DNS. We do this explicitly, rather than
+ letting the dmarc library do it with opendmarc_policy_query_dmarc(), so that
+ our dns access path is used for debug tracing and for the testsuite
+ diversion. */
+
+ libdm_status = (rr = dmarc_dns_lookup(header_from_sender))
+ ? opendmarc_policy_store_dmarc(dmarc_pctx, rr, header_from_sender, NULL)
+ : DMARC_DNS_ERROR_NO_RECORD;
switch (libdm_status)
{
case DMARC_DNS_ERROR_NXDOMAIN:
}
/* Can't use exim's string manipulation functions so allocate memory
- * for libopendmarc using its max hostname length definition. */
+ for libopendmarc using its max hostname length definition. */
- uschar *dmarc_domain = (uschar *)calloc(DMARC_MAXHOSTNAMELEN, sizeof(uschar));
+ dmarc_domain = store_get(DMARC_MAXHOSTNAMELEN, TRUE);
libdm_status = opendmarc_policy_fetch_utilized_domain(dmarc_pctx,
dmarc_domain, DMARC_MAXHOSTNAMELEN-1);
- dmarc_used_domain = string_copy(dmarc_domain);
- free(dmarc_domain);
+ store_release_above(dmarc_domain + Ustrlen(dmarc_domain)+1);
+ dmarc_used_domain = dmarc_domain;
if (libdm_status != DMARC_PARSE_OKAY)
log_write(0, LOG_MAIN|LOG_PANIC,
"failure to read domainname used for DMARC lookup: %s",
opendmarc_policy_status_to_str(libdm_status));
- libdm_status = opendmarc_get_policy_to_enforce(dmarc_pctx);
- dmarc_policy = libdm_status;
+ dmarc_policy = libdm_status = opendmarc_get_policy_to_enforce(dmarc_pctx);
switch(libdm_status)
{
case DMARC_POLICY_ABSENT: /* No DMARC record found */
log_write(0, LOG_MAIN|LOG_PANIC, "failure to read DMARC alignment: %s",
opendmarc_policy_status_to_str(libdm_status));
- if (has_dmarc_record == TRUE)
+ if (has_dmarc_record)
{
log_write(0, LOG_MAIN, "DMARC results: spf_domain=%s dmarc_domain=%s "
"spf_align=%s dkim_align=%s enforcement='%s'",
spf_sender_domain, dmarc_used_domain,
- (sa==DMARC_POLICY_SPF_ALIGNMENT_PASS) ?"yes":"no",
- (da==DMARC_POLICY_DKIM_ALIGNMENT_PASS)?"yes":"no",
+ sa==DMARC_POLICY_SPF_ALIGNMENT_PASS ?"yes":"no",
+ da==DMARC_POLICY_DKIM_ALIGNMENT_PASS ?"yes":"no",
dmarc_status_text);
history_file_status = dmarc_write_history_file();
/* Now get the forensic reporting addresses, if any */
}
}
-/* set some global variables here */
-dmarc_ar_header = dmarc_auth_results_header(from_header, NULL);
-
/* shut down libopendmarc */
-if ( dmarc_pctx != NULL )
+if (dmarc_pctx)
(void) opendmarc_policy_connect_shutdown(dmarc_pctx);
-if ( dmarc_disable_verify == FALSE )
+if (!f.dmarc_disable_verify)
(void) opendmarc_policy_library_shutdown(&dmarc_ctx);
return OK;
}
-int
+static int
dmarc_write_history_file()
{
int history_file_fd;
uschar *history_buffer = NULL;
if (!dmarc_history_file)
+ {
+ DEBUG(D_receive) debug_printf("DMARC history file not set\n");
return DMARC_HIST_DISABLED;
+ }
history_file_fd = log_create(dmarc_history_file);
if (history_file_fd < 0)
-{
+ {
log_write(0, LOG_MAIN|LOG_PANIC, "failure to create DMARC history file: %s",
dmarc_history_file);
return DMARC_HIST_FILE_ERR;
-}
+ }
/* Generate the contents of the history file */
history_buffer = string_sprintf(
/* Write the contents to the history file */
DEBUG(D_receive)
debug_printf("DMARC logging history data for opendmarc reporting%s\n",
- (host_checking || running_in_test_harness) ? " (not really)" : "");
-if (host_checking || running_in_test_harness)
+ (host_checking || f.running_in_test_harness) ? " (not really)" : "");
+if (host_checking || f.running_in_test_harness)
{
DEBUG(D_receive)
debug_printf("DMARC history data for debugging:\n%s", history_buffer);
return DMARC_HIST_OK;
}
+
uschar *
dmarc_exim_expand_query(int what)
{
-if (dmarc_disable_verify || !dmarc_pctx)
+if (f.dmarc_disable_verify || !dmarc_pctx)
return dmarc_exim_expand_defaults(what);
-switch(what)
- {
- case DMARC_VERIFY_STATUS:
- return(dmarc_status);
- default:
- return US"";
- }
+if (what == DMARC_VERIFY_STATUS)
+ return dmarc_status;
+return US"";
}
uschar *
dmarc_exim_expand_defaults(int what)
{
-switch(what)
- {
- case DMARC_VERIFY_STATUS:
- return dmarc_disable_verify ? US"off" : US"none";
- default:
- return US"";
- }
+if (what == DMARC_VERIFY_STATUS)
+ return f.dmarc_disable_verify ? US"off" : US"none";
+return US"";
}
-uschar *
-dmarc_auth_results_header(header_line *from_header, uschar *hostname)
-{
-uschar *hdr_tmp = US"";
-
-/* Allow a server hostname to be passed to this function, but is
- * currently unused */
-if (!hostname)
- hostname = primary_hostname;
-hdr_tmp = string_sprintf("%s %s;", DMARC_AR_HEADER, hostname);
-
-#if 0
-/* I don't think this belongs here, but left it here commented out
- * because it was a lot of work to get working right. */
-if (spf_response != NULL) {
- uschar *dmarc_ar_spf = US"";
- int sr = 0;
- sr = spf_response->result;
- dmarc_ar_spf = (sr == SPF_RESULT_NEUTRAL) ? US"neutral" :
- (sr == SPF_RESULT_PASS) ? US"pass" :
- (sr == SPF_RESULT_FAIL) ? US"fail" :
- (sr == SPF_RESULT_SOFTFAIL) ? US"softfail" :
- US"none";
- hdr_tmp = string_sprintf("%s spf=%s (%s) smtp.mail=%s;",
- hdr_tmp, dmarc_ar_spf_result,
- spf_response->header_comment,
- expand_string(US"$sender_address") );
-}
-#endif
-hdr_tmp = string_sprintf("%s dmarc=%s", hdr_tmp, dmarc_pass_fail);
-if (header_from_sender)
- hdr_tmp = string_sprintf("%s header.from=%s",
- hdr_tmp, header_from_sender);
-return hdr_tmp;
+gstring *
+authres_dmarc(gstring * g)
+{
+if (f.dmarc_has_been_checked)
+ {
+ g = string_append(g, 2, US";\n\tdmarc=", dmarc_pass_fail);
+ if (header_from_sender)
+ g = string_append(g, 2, US" header.from=", header_from_sender);
+ }
+return g;
}
-# endif /* EXPERIMENTAL_SPF */
-#endif /* EXPERIMENTAL_DMARC */
+# endif /* SUPPORT_SPF */
+#endif /* SUPPORT_DMARC */
/* vi: aw ai sw=2
*/
git://git.exim.org / users / jgh / exim.git / blobdiff