/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
-/* Experimental DMARC support.
+/* DMARC support.
+ Copyright (c) The Exim Maintainers 2019 - 2023
Copyright (c) Todd Lyons <tlyons@exim.org> 2012 - 2014
License: GPL */
+/* SPDX-License-Identifier: GPL-2.0-or-later */
/* Portions Copyright (c) 2012, 2013, The Trusted Domain Project;
All rights reserved, licensed for use per LICENSE.opendmarc. */
/* Code for calling dmarc checks via libopendmarc. Called from acl.c. */
#include "exim.h"
-#ifdef EXPERIMENTAL_DMARC
+#ifdef SUPPORT_DMARC
# if !defined SUPPORT_SPF
# error SPF must also be enabled for DMARC
# elif defined DISABLE_DKIM
uschar *spf_human_readable = NULL;
u_char *header_from_sender = NULL;
int history_file_status = DMARC_HIST_OK;
-uschar *dkim_history_buffer= NULL;
typedef struct dmarc_exim_p {
uschar *name;
{ US"reject", DMARC_RECORD_P_REJECT },
{ NULL, 0 }
};
+
+
+gstring *
+dmarc_version_report(gstring * g)
+{
+return string_fmt_append(g, "Library version: dmarc: Compile: %d.%d.%d.%d\n",
+ (OPENDMARC_LIB_VERSION & 0xff000000) >> 24, (OPENDMARC_LIB_VERSION & 0x00ff0000) >> 16,
+ (OPENDMARC_LIB_VERSION & 0x0000ff00) >> 8, OPENDMARC_LIB_VERSION & 0x000000ff);
+}
+
+
/* Accept an error_block struct, initialize if empty, parse to the
- * end, and append the two strings passed to it. Used for adding
- * variable amounts of value:pair data to the forensic emails. */
+end, and append the two strings passed to it. Used for adding
+variable amounts of value:pair data to the forensic emails. */
static error_block *
add_to_eblock(error_block *eblock, uschar *t1, uschar *t2)
{
error_block *eb = store_malloc(sizeof(error_block));
-if (eblock == NULL)
+if (!eblock)
eblock = eb;
else
{
/* Find the end of the eblock struct and point it at eb */
error_block *tmp = eblock;
- while(tmp->next != NULL)
+ while(tmp->next)
tmp = tmp->next;
tmp->next = eb;
}
}
/* dmarc_init sets up a context that can be re-used for several
- messages on the same SMTP connection (that come from the
- same host with the same HELO string) */
+messages on the same SMTP connection (that come from the
+same host with the same HELO string) */
int
-dmarc_init()
+dmarc_init(void)
{
int *netmask = NULL; /* Ignored */
int is_ipv6 = 0;
/* Set some sane defaults. Also clears previous results when
- * multiple messages in one connection. */
+multiple messages in one connection. */
+
dmarc_pctx = NULL;
dmarc_status = US"none";
dmarc_abort = FALSE;
opendmarc_policy_status_to_str(libdm_status));
dmarc_abort = TRUE;
}
-if (!dmarc_tld_file)
+if (!dmarc_tld_file || !*dmarc_tld_file)
{
- DEBUG(D_receive) debug_printf("DMARC: no dmarc_tld_file\n");
+ DEBUG(D_receive) debug_printf_indent("DMARC: no dmarc_tld_file\n");
dmarc_abort = TRUE;
}
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",
- dmarc_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)
{
- DEBUG(D_receive) debug_printf("DMARC: no sender_host_address\n");
+ DEBUG(D_receive) debug_printf_indent("DMARC: no sender_host_address\n");
dmarc_abort = TRUE;
}
/* This catches locally originated email and startup errors above. */
}
-/* dmarc_store_data stores the header data so that subsequent
-dmarc_process can access the data */
+/* dmarc_store_data stores the header data so that subsequent dmarc_process can
+access the data.
+Called after the entire message has been received, with the From: header. */
int
-dmarc_store_data(header_line *hdr)
+dmarc_store_data(header_line * hdr)
{
/* No debug output because would change every test debug output */
if (!f.dmarc_disable_verify)
static void
-dmarc_send_forensic_report(u_char **ruf)
+dmarc_send_forensic_report(u_char ** ruf)
{
uschar *recipient, *save_sender;
BOOL send_status = FALSE;
/* Move to first character past the colon */
recipient += 7;
DEBUG(D_receive)
- debug_printf("DMARC forensic report to %s%s\n", recipient,
+ debug_printf_indent("DMARC forensic report to %s%s\n", recipient,
(host_checking || f.running_in_test_harness) ? " (not really)" : "");
if (host_checking || f.running_in_test_harness)
continue;
}
}
+
+/* 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)
+ {
+ uschar *record = string_copyn_taint(US rr->data, rr->size, GET_TAINTED);
+ store_free_dns_answer(dnsa);
+ return record;
+ }
+store_free_dns_answer(dnsa);
+return NULL;
+}
+
+
+static int
+dmarc_write_history_file(const gstring * dkim_history_buffer)
+{
+int history_file_fd = 0;
+ssize_t written_len;
+int tmp_ans;
+u_char ** rua; /* aggregate report addressees */
+gstring * g;
+
+if (!dmarc_history_file)
+ {
+ DEBUG(D_receive) debug_printf_indent("DMARC history file not set\n");
+ return DMARC_HIST_DISABLED;
+ }
+if (!host_checking)
+ {
+ uschar * s = string_copy(dmarc_history_file); /* need a writeable copy */
+ if ((history_file_fd = log_open_as_exim(s)) < 0)
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC,
+ "failure to create DMARC history file: %s: %s",
+ s, strerror(errno));
+ return DMARC_HIST_FILE_ERR;
+ }
+ }
+
+/* Generate the contents of the history file entry */
+
+g = string_fmt_append(NULL,
+ "job %s\nreporter %s\nreceived %ld\nipaddr %s\nfrom %s\nmfrom %s\n",
+ message_id, primary_hostname, time(NULL), sender_host_address,
+ header_from_sender, expand_string(US"$sender_address_domain"));
+
+if (spf_response)
+ g = string_fmt_append(g, "spf %d\n", dmarc_spf_ares_result);
+
+if (dkim_history_buffer)
+ g = string_fmt_append(g, "%Y", dkim_history_buffer);
+
+g = string_fmt_append(g, "pdomain %s\npolicy %d\n",
+ dmarc_used_domain, dmarc_policy);
+
+if ((rua = opendmarc_policy_fetch_rua(dmarc_pctx, NULL, 0, 1)))
+ for (tmp_ans = 0; rua[tmp_ans]; tmp_ans++)
+ g = string_fmt_append(g, "rua %s\n", rua[tmp_ans]);
+else
+ g = string_catn(g, US"rua -\n", 6);
+
+opendmarc_policy_fetch_pct(dmarc_pctx, &tmp_ans);
+g = string_fmt_append(g, "pct %d\n", tmp_ans);
+
+opendmarc_policy_fetch_adkim(dmarc_pctx, &tmp_ans);
+g = string_fmt_append(g, "adkim %d\n", tmp_ans);
+
+opendmarc_policy_fetch_aspf(dmarc_pctx, &tmp_ans);
+g = string_fmt_append(g, "aspf %d\n", tmp_ans);
+
+opendmarc_policy_fetch_p(dmarc_pctx, &tmp_ans);
+g = string_fmt_append(g, "p %d\n", tmp_ans);
+
+opendmarc_policy_fetch_sp(dmarc_pctx, &tmp_ans);
+g = string_fmt_append(g, "sp %d\n", tmp_ans);
+
+g = string_fmt_append(g, "align_dkim %d\nalign_spf %d\naction %d\n",
+ da, sa, action);
+
+#if DMARC_API >= 100400
+# ifdef EXPERIMENTAL_ARC
+g = arc_dmarc_hist_append(g);
+# else
+g = string_fmt_append(g, "arc %d\narc_policy $d json:[]\n",
+ ARES_RESULT_UNKNOWN, DMARC_ARC_POLICY_RESULT_UNUSED);
+# endif
+#endif
+
+/* Write the contents to the history file */
+DEBUG(D_receive)
+ {
+ debug_printf_indent("DMARC logging history data for opendmarc reporting%s\n",
+ host_checking ? " (not really)" : "");
+ debug_printf_indent("DMARC history data for debugging:\n");
+ expand_level++;
+ debug_printf_indent("%Y", g);
+ expand_level--;
+ }
+
+if (!host_checking)
+ {
+ written_len = write_to_fd_buf(history_file_fd,
+ g->s,
+ gstring_length(g));
+ if (written_len == 0)
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC, "failure to write to DMARC history file: %s",
+ dmarc_history_file);
+ return DMARC_HIST_WRITE_ERR;
+ }
+ (void)close(history_file_fd);
+ }
+return DMARC_HIST_OK;
+}
+
+
/* 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. */
+strings and evaluates the condition outcome.
+Called for the first ACL dmarc= condition. */
int
-dmarc_process()
+dmarc_process(void)
{
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 = dkim_signatures;
+uschar * rr;
BOOL has_dmarc_record = TRUE;
-u_char **ruf; /* forensic report addressees, if called for */
+u_char ** ruf; /* forensic report addressees, if called for */
/* ACLs have "control=dmarc_disable_verify" */
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
- * is locally generated and relying on fixups to add it. Just skip
- * the entire DMARC system if we can't find a From: header....or if
- * there was a previous error.
- */
+If there is no from_header struct, then it's likely this message
+is locally generated and relying on fixups to add it. Just skip
+the entire DMARC system if we can't find a From: header....or if
+there was a previous error. */
+
if (!from_header)
{
- DEBUG(D_receive) debug_printf("DMARC: no From: header\n");
+ DEBUG(D_receive) debug_printf_indent("DMARC: no From: header\n");
dmarc_abort = TRUE;
}
else if (!dmarc_abort)
*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. */
+ 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
}
/* Skip DMARC if connection is SMTP Auth. Temporarily, admin should
- * instead do this in the ACLs. */
+instead do this in the ACLs. */
+
if (!dmarc_abort && !sender_host_authenticated)
{
uschar * dmarc_domain;
+ gstring * dkim_history_buffer = NULL;
/* Use the envelope sender domain for this part of DMARC */
+
spf_sender_domain = expand_string(US"$sender_address_domain");
if (!spf_response)
{
/* No spf data means null envelope sender so generate a domain name
- * from the sender_helo_name */
+ from the sender_helo_name */
+
if (!spf_sender_domain)
{
spf_sender_domain = sender_helo_name;
log_write(0, LOG_MAIN, "DMARC using synthesized SPF sender domain = %s\n",
spf_sender_domain);
DEBUG(D_receive)
- debug_printf("DMARC using synthesized SPF sender domain = %s\n",
+ debug_printf_indent("DMARC using synthesized SPF sender domain = %s\n",
spf_sender_domain);
}
dmarc_spf_result = DMARC_POLICY_SPF_OUTCOME_NONE;
origin = DMARC_POLICY_SPF_ORIGIN_MAILFROM;
spf_human_readable = US spf_response->header_comment;
DEBUG(D_receive)
- debug_printf("DMARC using SPF sender domain = %s\n", spf_sender_domain);
+ debug_printf_indent("DMARC using SPF sender domain = %s\n", spf_sender_domain);
}
if (strcmp( CCS spf_sender_domain, "") == 0)
dmarc_abort = TRUE;
}
/* Now we cycle through the dkim signature results and put into
- * the opendmarc context, further building the DMARC reply. */
- dkim_history_buffer = US"";
- while (sig)
+ the opendmarc context, further building the DMARC reply. */
+
+ for(pdkim_signature * sig = dkim_signatures; sig; sig = sig->next)
{
int dkim_result, dkim_ares_result, vs, ves;
vs == PDKIM_VERIFY_INVALID ? DMARC_POLICY_DKIM_OUTCOME_TMPFAIL :
DMARC_POLICY_DKIM_OUTCOME_NONE;
libdm_status = opendmarc_policy_store_dkim(dmarc_pctx, US sig->domain,
- dkim_result, US"");
+
+/* The opendmarc project broke its API in a way we can't detect easily.
+The EDITME provides a DMARC_API variable */
+#if DMARC_API >= 100400
+ sig->selector,
+#endif
+ dkim_result, US"");
DEBUG(D_receive)
- debug_printf("DMARC adding DKIM sender domain = %s\n", sig->domain);
+ debug_printf_indent("DMARC adding DKIM sender domain = %s\n", sig->domain);
if (libdm_status != DMARC_PARSE_OKAY)
log_write(0, LOG_MAIN|LOG_PANIC,
"failure to store dkim (%s) for DMARC: %s",
ves == PDKIM_VERIFY_INVALID_PUBKEY_IMPORT ? ARES_RESULT_PERMERROR :
ARES_RESULT_UNKNOWN :
ARES_RESULT_UNKNOWN;
- dkim_history_buffer = string_sprintf("%sdkim %s %d\n", dkim_history_buffer,
- sig->domain, dkim_ares_result);
- sig = sig->next;
+#if DMARC_API >= 100400
+ dkim_history_buffer = string_fmt_append(dkim_history_buffer,
+ "dkim %s %s %d\n", sig->domain, sig->selector, dkim_ares_result);
+#else
+ dkim_history_buffer = string_fmt_append(dkim_history_buffer,
+ "dkim %s %d\n", sig->domain, dkim_ares_result);
+#endif
}
- 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:
case DMARC_DNS_ERROR_NO_RECORD:
DEBUG(D_receive)
- debug_printf("DMARC no record found for %s\n", header_from_sender);
+ debug_printf_indent("DMARC no record found for %s\n", header_from_sender);
has_dmarc_record = FALSE;
break;
case DMARC_PARSE_OKAY:
DEBUG(D_receive)
- debug_printf("DMARC record found for %s\n", header_from_sender);
+ debug_printf_indent("DMARC record found for %s\n", header_from_sender);
break;
case DMARC_PARSE_ERROR_BAD_VALUE:
DEBUG(D_receive)
- debug_printf("DMARC record parse error for %s\n", header_from_sender);
+ debug_printf_indent("DMARC record parse error for %s\n", header_from_sender);
has_dmarc_record = FALSE;
break;
default:
/* everything else, skip dmarc */
DEBUG(D_receive)
- debug_printf("DMARC skipping (%d), unsure what to do with %s",
- libdm_status, from_header->text);
+ debug_printf_indent("DMARC skipping (%s), unsure what to do with %s",
+ opendmarc_policy_status_to_str(libdm_status),
+ from_header->text);
has_dmarc_record = FALSE;
break;
}
-/* Store the policy string in an expandable variable. */
+ /* Store the policy string in an expandable variable. */
libdm_status = opendmarc_policy_fetch_p(dmarc_pctx, &tmp_ans);
for (c = 0; dmarc_policy_description[c].name; c++)
/* Can't use exim's string manipulation functions so allocate memory
for libopendmarc using its max hostname length definition. */
- dmarc_domain = US calloc(DMARC_MAXHOSTNAMELEN, sizeof(uschar));
+ dmarc_domain = store_get(DMARC_MAXHOSTNAMELEN, GET_TAINTED);
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,
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();
+ history_file_status = dmarc_write_history_file(dkim_history_buffer);
/* Now get the forensic reporting addresses, if any */
ruf = opendmarc_policy_fetch_ruf(dmarc_pctx, NULL, 0, 1);
dmarc_send_forensic_report(ruf);
return OK;
}
-static int
-dmarc_write_history_file()
-{
-int history_file_fd;
-ssize_t written_len;
-int tmp_ans;
-u_char **rua; /* aggregate report addressees */
-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(
- "job %s\nreporter %s\nreceived %ld\nipaddr %s\nfrom %s\nmfrom %s\n",
- message_id, primary_hostname, time(NULL), sender_host_address,
- header_from_sender, expand_string(US"$sender_address_domain"));
-
-if (spf_response)
- history_buffer = string_sprintf("%sspf %d\n", history_buffer, dmarc_spf_ares_result);
- /* history_buffer = string_sprintf("%sspf -1\n", history_buffer); */
-
-history_buffer = string_sprintf(
- "%s%spdomain %s\npolicy %d\n",
- history_buffer, dkim_history_buffer, dmarc_used_domain, dmarc_policy);
-
-if ((rua = opendmarc_policy_fetch_rua(dmarc_pctx, NULL, 0, 1)))
- for (tmp_ans = 0; rua[tmp_ans]; tmp_ans++)
- history_buffer = string_sprintf("%srua %s\n", history_buffer, rua[tmp_ans]);
-else
- history_buffer = string_sprintf("%srua -\n", history_buffer);
-
-opendmarc_policy_fetch_pct(dmarc_pctx, &tmp_ans);
-history_buffer = string_sprintf("%spct %d\n", history_buffer, tmp_ans);
-
-opendmarc_policy_fetch_adkim(dmarc_pctx, &tmp_ans);
-history_buffer = string_sprintf("%sadkim %d\n", history_buffer, tmp_ans);
-
-opendmarc_policy_fetch_aspf(dmarc_pctx, &tmp_ans);
-history_buffer = string_sprintf("%saspf %d\n", history_buffer, tmp_ans);
-
-opendmarc_policy_fetch_p(dmarc_pctx, &tmp_ans);
-history_buffer = string_sprintf("%sp %d\n", history_buffer, tmp_ans);
-
-opendmarc_policy_fetch_sp(dmarc_pctx, &tmp_ans);
-history_buffer = string_sprintf("%ssp %d\n", history_buffer, tmp_ans);
-
-history_buffer = string_sprintf(
- "%salign_dkim %d\nalign_spf %d\naction %d\n",
- history_buffer, da, sa, action);
-
-/* Write the contents to the history file */
-DEBUG(D_receive)
- debug_printf("DMARC logging history data for opendmarc reporting%s\n",
- (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);
- }
-else
- {
- written_len = write_to_fd_buf(history_file_fd,
- history_buffer,
- Ustrlen(history_buffer));
- if (written_len == 0)
- {
- log_write(0, LOG_MAIN|LOG_PANIC, "failure to write to DMARC history file: %s",
- dmarc_history_file);
- return DMARC_HIST_WRITE_ERR;
- }
- (void)close(history_file_fd);
- }
-return DMARC_HIST_OK;
-}
-
-
uschar *
dmarc_exim_expand_query(int what)
{
{
if (f.dmarc_has_been_checked)
{
+ int start = 0; /* Compiler quietening */
+ DEBUG(D_acl) start = gstring_length(g);
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);
+ DEBUG(D_acl) debug_printf("DMARC:\tauthres '%.*s'\n",
+ gstring_length(g) - start - 3, g->s + start + 3);
}
+else
+ DEBUG(D_acl) debug_printf("DMARC:\tno authres\n");
return g;
}
# endif /* SUPPORT_SPF */
-#endif /* EXPERIMENTAL_DMARC */
+#endif /* SUPPORT_DMARC */
/* vi: aw ai sw=2
*/
git://git.exim.org / exim.git / blobdiff