* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2012 */
+/* Copyright (c) University of Cambridge 1995 - 2018 */
/* See the file NOTICE for conditions of use and distribution. */
#include "../exim.h"
header files. */
#ifndef T_TXT
-#define T_TXT 16
+# define T_TXT 16
#endif
/* Many systems do not have T_SPF. */
#ifndef T_SPF
-#define T_SPF 99
+# define T_SPF 99
+#endif
+
+/* New TLSA record for DANE */
+#ifndef T_TLSA
+# define T_TLSA 52
#endif
/* Table of recognized DNS record types and their integer values. */
static const char *type_names[] = {
"a",
#if HAVE_IPV6
+ "a+",
"aaaa",
- #ifdef SUPPORT_A6
- "a6",
- #endif
#endif
"cname",
"csa",
"mxh",
"ns",
"ptr",
+ "soa",
"spf",
"srv",
+ "tlsa",
"txt",
"zns"
};
static int type_values[] = {
T_A,
#if HAVE_IPV6
+ T_ADDRESSES, /* Private type for AAAA + A */
T_AAAA,
- #ifdef SUPPORT_A6
- T_A6,
- #endif
#endif
T_CNAME,
T_CSA, /* Private type for "Client SMTP Authorization". */
T_MXH, /* Private type for "MX hostnames" */
T_NS,
T_PTR,
+ T_SOA,
T_SPF,
T_SRV,
+ T_TLSA,
T_TXT,
T_ZNS /* Private type for "zone nameservers" */
};
is output. Similarly for "SPF" records, but the default for joining multiple
items in one SPF record is the empty string, for direct concatenation.
-(c) If the next sequence of characters is 'defer_FOO' followed by a comma,
-the defer behaviour is set to FOO. The possible behaviours are: 'strict', where
-any defer causes the whole lookup to defer; 'lax', where a defer causes the
-whole lookup to defer only if none of the DNS queries succeeds; and 'never',
-where all defers are as if the lookup failed. The default is 'lax'.
+(c) Options, all comma-terminated, in any order. Any unrecognised option
+terminates option processing. Recognised options are:
+
+- 'defer_FOO': set the defer behaviour to FOO. The possible behaviours are:
+'strict', where any defer causes the whole lookup to defer; 'lax', where a defer
+causes the whole lookup to defer only if none of the DNS queries succeeds; and
+'never', where all defers are as if the lookup failed. The default is 'lax'.
+
+- 'dnssec_FOO', with 'strict', 'lax' and 'never' (default). The meanings are
+require, try and don't-try dnssec respectively.
+
+- 'retrans_VAL', set the timeout value. VAL is an Exim time specification
+(eg "5s"). The default is set by the main configuration option 'dns_retrans'.
+
+- 'retry_VAL', set the retry count on timeouts. VAL is an integer. The
+default is set by the main configuration option "dns_retry".
(d) If the next sequence of characters is a sequence of letters and digits
followed by '=', it is interpreted as the name of the DNS record type. The
separator, as always, is colon. */
static int
-dnsdb_find(void *handle, uschar *filename, uschar *keystring, int length,
- uschar **result, uschar **errmsg, BOOL *do_cache)
+dnsdb_find(void *handle, uschar *filename, const uschar *keystring, int length,
+ uschar **result, uschar **errmsg, uint *do_cache)
{
int rc;
-int size = 256;
-int ptr = 0;
int sep = 0;
int defer_mode = PASS;
-int type = T_TXT;
+int dnssec_mode = OK;
+int save_retrans = dns_retrans;
+int save_retry = dns_retry;
+int type;
int failrc = FAIL;
-uschar *outsep = US"\n";
-uschar *outsep2 = NULL;
+const uschar *outsep = CUS"\n";
+const uschar *outsep2 = NULL;
uschar *equals, *domain, *found;
-uschar buffer[256];
-/* Because we're the working in the search pool, we try to reclaim as much
+/* Because we're working in the search pool, we try to reclaim as much
store as possible later, so we preallocate the result here */
-uschar *yield = store_get(size);
+gstring * yield = string_get(256);
-dns_record *rr;
dns_answer dnsa;
dns_scan dnss;
while (isspace(*keystring)) keystring++;
}
-/* SPF strings should be concatenated without a separator, thus make
-it the default if not defined (see RFC 4408 section 3.1.3).
-Multiple SPF records are forbidden (section 3.1.2) but are currently
-not handled specially, thus they are concatenated with \n by default. */
-
-if (type == T_SPF && outsep2 == NULL)
- outsep2 = US"";
-
-/* Check for a defer behaviour keyword. */
+/* Check for a modifier keyword. */
-if (strncmpic(keystring, US"defer_", 6) == 0)
+for (;;)
{
- keystring += 6;
- if (strncmpic(keystring, US"strict", 6) == 0)
+ if (strncmpic(keystring, US"defer_", 6) == 0)
{
- defer_mode = DEFER;
keystring += 6;
+ if (strncmpic(keystring, US"strict", 6) == 0)
+ { defer_mode = DEFER; keystring += 6; }
+ else if (strncmpic(keystring, US"lax", 3) == 0)
+ { defer_mode = PASS; keystring += 3; }
+ else if (strncmpic(keystring, US"never", 5) == 0)
+ { defer_mode = OK; keystring += 5; }
+ else
+ {
+ *errmsg = US"unsupported dnsdb defer behaviour";
+ return DEFER;
+ }
}
- else if (strncmpic(keystring, US"lax", 3) == 0)
+ else if (strncmpic(keystring, US"dnssec_", 7) == 0)
{
- defer_mode = PASS;
- keystring += 3;
+ keystring += 7;
+ if (strncmpic(keystring, US"strict", 6) == 0)
+ { dnssec_mode = DEFER; keystring += 6; }
+ else if (strncmpic(keystring, US"lax", 3) == 0)
+ { dnssec_mode = PASS; keystring += 3; }
+ else if (strncmpic(keystring, US"never", 5) == 0)
+ { dnssec_mode = OK; keystring += 5; }
+ else
+ {
+ *errmsg = US"unsupported dnsdb dnssec behaviour";
+ return DEFER;
+ }
}
- else if (strncmpic(keystring, US"never", 5) == 0)
+ else if (strncmpic(keystring, US"retrans_", 8) == 0)
{
- defer_mode = OK;
- keystring += 5;
+ int timeout_sec;
+ if ((timeout_sec = readconf_readtime(keystring += 8, ',', FALSE)) <= 0)
+ {
+ *errmsg = US"unsupported dnsdb timeout value";
+ return DEFER;
+ }
+ dns_retrans = timeout_sec;
+ while (*keystring != ',') keystring++;
}
- else
+ else if (strncmpic(keystring, US"retry_", 6) == 0)
{
- *errmsg = US"unsupported dnsdb defer behaviour";
- return DEFER;
+ int retries;
+ if ((retries = (int)strtol(CCS keystring + 6, CSS &keystring, 0)) < 0)
+ {
+ *errmsg = US"unsupported dnsdb retry count";
+ return DEFER;
+ }
+ dns_retry = retries;
}
+ else
+ break;
+
while (isspace(*keystring)) keystring++;
if (*keystring++ != ',')
{
- *errmsg = US"dnsdb defer behaviour syntax error";
+ *errmsg = US"dnsdb modifier syntax error";
return DEFER;
}
while (isspace(*keystring)) keystring++;
}
-/* If the keystring contains an = this must be preceded by a valid type name. */
+/* Figure out the "type" value if it is not T_TXT.
+If the keystring contains an = this must be preceded by a valid type name. */
+type = T_TXT;
if ((equals = Ustrchr(keystring, '=')) != NULL)
{
int i, len;
while (tend > keystring && isspace(tend[-1])) tend--;
len = tend - keystring;
- for (i = 0; i < sizeof(type_names)/sizeof(uschar *); i++)
- {
+ for (i = 0; i < nelem(type_names); i++)
if (len == Ustrlen(type_names[i]) &&
strncmpic(keystring, US type_names[i], len) == 0)
{
type = type_values[i];
break;
}
- }
- if (i >= sizeof(type_names)/sizeof(uschar *))
+ if (i >= nelem(type_names))
{
*errmsg = US"unsupported DNS record type";
return DEFER;
/* Initialize the resolver in case this is the first time it has been used. */
-dns_init(FALSE, FALSE);
+dns_init(FALSE, FALSE, dnssec_mode != OK);
/* The remainder of the string must be a list of domains. As long as the lookup
for at least one of them succeeds, we return success. Failure means that none
string_is_ip_address(keystring, NULL) != 0)
sep = -1;
+/* SPF strings should be concatenated without a separator, thus make
+it the default if not defined (see RFC 4408 section 3.1.3).
+Multiple SPF records are forbidden (section 3.1.2) but are currently
+not handled specially, thus they are concatenated with \n by default.
+MX priority and value are space-separated by default.
+SRV and TLSA record parts are space-separated by default. */
+
+if (!outsep2) switch(type)
+ {
+ case T_SPF: outsep2 = US""; break;
+ case T_SRV: case T_MX: case T_TLSA: outsep2 = US" "; break;
+ }
+
/* Now scan the list and do a lookup for each item */
-while ((domain = string_nextinlist(&keystring, &sep, buffer, sizeof(buffer)))
- != NULL)
+while ((domain = string_nextinlist(&keystring, &sep, NULL, 0)))
{
uschar rbuffer[256];
int searchtype = (type == T_CSA)? T_SRV : /* record type we want */
domain = rbuffer;
}
- DEBUG(D_lookup) debug_printf("dnsdb key: %s\n", domain);
-
- /* Do the lookup and sort out the result. There are three special types that
- are handled specially: T_CSA, T_ZNS and T_MXH. The former two are handled in
- a special lookup function so that the facility could be used from other
- parts of the Exim code. The latter affects only what happens later on in
- this function, but for tidiness it is handled in a similar way. If the
- lookup fails, continue with the next domain. In the case of DEFER, adjust
- the final "nothing found" result, but carry on to the next domain. */
-
- found = domain;
- rc = dns_special_lookup(&dnsa, domain, type, &found);
-
- if (rc == DNS_NOMATCH || rc == DNS_NODATA) continue;
- if (rc != DNS_SUCCEED)
- {
- if (defer_mode == DEFER) return DEFER; /* always defer */
- else if (defer_mode == PASS) failrc = DEFER; /* defer only if all do */
- continue; /* treat defer as fail */
- }
-
- /* Search the returned records */
-
- for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
- rr != NULL;
- rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
+ do
{
- if (rr->type != searchtype) continue;
+ DEBUG(D_lookup) debug_printf("dnsdb key: %s\n", domain);
+
+ /* Do the lookup and sort out the result. There are four special types that
+ are handled specially: T_CSA, T_ZNS, T_ADDRESSES and T_MXH.
+ The first two are handled in a special lookup function so that the facility
+ could be used from other parts of the Exim code. T_ADDRESSES is handled by looping
+ over the types of A lookup. T_MXH affects only what happens later on in
+ this function, but for tidiness it is handled by the "special". If the
+ lookup fails, continue with the next domain. In the case of DEFER, adjust
+ the final "nothing found" result, but carry on to the next domain. */
+
+ found = domain;
+#if HAVE_IPV6
+ if (type == T_ADDRESSES) /* NB cannot happen unless HAVE_IPV6 */
+ {
+ if (searchtype == T_ADDRESSES) searchtype = T_AAAA;
+ else if (searchtype == T_AAAA) searchtype = T_A;
+ rc = dns_special_lookup(&dnsa, domain, searchtype, CUSS &found);
+ }
+ else
+#endif
+ rc = dns_special_lookup(&dnsa, domain, type, CUSS &found);
- /* There may be several addresses from an A6 record. Put the configured
- separator between them, just as for between several records. However, A6
- support is not normally configured these days. */
+ lookup_dnssec_authenticated = dnssec_mode==OK ? NULL
+ : dns_is_secure(&dnsa) ? US"yes" : US"no";
- if (type == T_A ||
- #ifdef SUPPORT_A6
- type == T_A6 ||
- #endif
- type == T_AAAA)
+ if (rc == DNS_NOMATCH || rc == DNS_NODATA) continue;
+ if ( rc != DNS_SUCCEED
+ || (dnssec_mode == DEFER && !dns_is_secure(&dnsa))
+ )
{
- dns_address *da;
- for (da = dns_address_from_rr(&dnsa, rr); da != NULL; da = da->next)
- {
- if (ptr != 0) yield = string_cat(yield, &size, &ptr, outsep, 1);
- yield = string_cat(yield, &size, &ptr, da->address,
- Ustrlen(da->address));
- }
- continue;
+ if (defer_mode == DEFER)
+ {
+ dns_retrans = save_retrans;
+ dns_retry = save_retry;
+ dns_init(FALSE, FALSE, FALSE); /* clr dnssec bit */
+ return DEFER; /* always defer */
+ }
+ if (defer_mode == PASS) failrc = DEFER; /* defer only if all do */
+ continue; /* treat defer as fail */
}
- /* Other kinds of record just have one piece of data each, but there may be
- several of them, of course. */
- if (ptr != 0) yield = string_cat(yield, &size, &ptr, outsep, 1);
+ /* Search the returned records */
- if (type == T_TXT || type == T_SPF)
+ for (dns_record * rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); rr;
+ rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) if (rr->type == searchtype)
{
- if (outsep2 == NULL)
- {
- /* output only the first item of data */
- yield = string_cat(yield, &size, &ptr, (uschar *)(rr->data+1),
- (rr->data)[0]);
- }
- else
+ if (*do_cache > rr->ttl)
+ *do_cache = rr->ttl;
+
+ if (type == T_A || type == T_AAAA || type == T_ADDRESSES)
{
- /* output all items */
- int data_offset = 0;
- while (data_offset < rr->size)
+ for (dns_address * da = dns_address_from_rr(&dnsa, rr); da; da = da->next)
{
- uschar chunk_len = (rr->data)[data_offset++];
- if (outsep2[0] != '\0' && data_offset != 1)
- yield = string_cat(yield, &size, &ptr, outsep2, 1);
- yield = string_cat(yield, &size, &ptr,
- (uschar *)((rr->data)+data_offset), chunk_len);
- data_offset += chunk_len;
+ if (yield->ptr) yield = string_catn(yield, outsep, 1);
+ yield = string_cat(yield, da->address);
}
+ continue;
}
- }
- else /* T_CNAME, T_CSA, T_MX, T_MXH, T_NS, T_PTR, T_SRV */
- {
- int priority, weight, port;
- uschar s[264];
- uschar *p = (uschar *)(rr->data);
- if (type == T_MXH)
- {
- /* mxh ignores the priority number and includes only the hostnames */
- GETSHORT(priority, p);
- }
- else if (type == T_MX)
+ /* Other kinds of record just have one piece of data each, but there may be
+ several of them, of course. */
+
+ if (yield->ptr) yield = string_catn(yield, outsep, 1);
+
+ if (type == T_TXT || type == T_SPF)
{
- GETSHORT(priority, p);
- sprintf(CS s, "%d ", priority);
- yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
+ if (outsep2 == NULL) /* output only the first item of data */
+ yield = string_catn(yield, US (rr->data+1), (rr->data)[0]);
+ else
+ {
+ /* output all items */
+ int data_offset = 0;
+ while (data_offset < rr->size)
+ {
+ uschar chunk_len = (rr->data)[data_offset++];
+ if (outsep2[0] != '\0' && data_offset != 1)
+ yield = string_catn(yield, outsep2, 1);
+ yield = string_catn(yield, US ((rr->data)+data_offset), chunk_len);
+ data_offset += chunk_len;
+ }
+ }
}
- else if (type == T_SRV)
+ else if (type == T_TLSA)
{
- GETSHORT(priority, p);
- GETSHORT(weight, p);
- GETSHORT(port, p);
- sprintf(CS s, "%d %d %d ", priority, weight, port);
- yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
+ uint8_t usage, selector, matching_type;
+ uint16_t payload_length;
+ uschar s[MAX_TLSA_EXPANDED_SIZE];
+ uschar * sp = s;
+ uschar * p = US rr->data;
+
+ usage = *p++;
+ selector = *p++;
+ matching_type = *p++;
+ /* What's left after removing the first 3 bytes above */
+ payload_length = rr->size - 3;
+ sp += sprintf(CS s, "%d%c%d%c%d%c", usage, *outsep2,
+ selector, *outsep2, matching_type, *outsep2);
+ /* Now append the cert/identifier, one hex char at a time */
+ while (payload_length-- > 0 && sp-s < (MAX_TLSA_EXPANDED_SIZE - 4))
+ sp += sprintf(CS sp, "%02x", *p++);
+
+ yield = string_cat(yield, s);
}
- else if (type == T_CSA)
+ else /* T_CNAME, T_CSA, T_MX, T_MXH, T_NS, T_PTR, T_SOA, T_SRV */
{
- /* See acl_verify_csa() for more comments about CSA. */
-
- GETSHORT(priority, p);
- GETSHORT(weight, p);
- GETSHORT(port, p);
-
- if (priority != 1) continue; /* CSA version must be 1 */
-
- /* If the CSA record we found is not the one we asked for, analyse
- the subdomain assertions in the port field, else analyse the direct
- authorization status in the weight field. */
-
- if (found != domain)
- {
- if (port & 1) *s = 'X'; /* explicit authorization required */
- else *s = '?'; /* no subdomain assertions here */
- }
- else
+ int priority, weight, port;
+ uschar s[264];
+ uschar * p = US rr->data;
+
+ switch (type)
+ {
+ case T_MXH:
+ /* mxh ignores the priority number and includes only the hostnames */
+ GETSHORT(priority, p);
+ break;
+
+ case T_MX:
+ GETSHORT(priority, p);
+ sprintf(CS s, "%d%c", priority, *outsep2);
+ yield = string_cat(yield, s);
+ break;
+
+ case T_SRV:
+ GETSHORT(priority, p);
+ GETSHORT(weight, p);
+ GETSHORT(port, p);
+ sprintf(CS s, "%d%c%d%c%d%c", priority, *outsep2,
+ weight, *outsep2, port, *outsep2);
+ yield = string_cat(yield, s);
+ break;
+
+ case T_CSA:
+ /* See acl_verify_csa() for more comments about CSA. */
+ GETSHORT(priority, p);
+ GETSHORT(weight, p);
+ GETSHORT(port, p);
+
+ if (priority != 1) continue; /* CSA version must be 1 */
+
+ /* If the CSA record we found is not the one we asked for, analyse
+ the subdomain assertions in the port field, else analyse the direct
+ authorization status in the weight field. */
+
+ if (Ustrcmp(found, domain) != 0)
+ {
+ if (port & 1) *s = 'X'; /* explicit authorization required */
+ else *s = '?'; /* no subdomain assertions here */
+ }
+ else
+ {
+ if (weight < 2) *s = 'N'; /* not authorized */
+ else if (weight == 2) *s = 'Y'; /* authorized */
+ else if (weight == 3) *s = '?'; /* unauthorizable */
+ else continue; /* invalid */
+ }
+
+ s[1] = ' ';
+ yield = string_catn(yield, s, 2);
+ break;
+
+ default:
+ break;
+ }
+
+ /* GETSHORT() has advanced the pointer to the target domain. */
+
+ rc = dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, p,
+ (DN_EXPAND_ARG4_TYPE)s, sizeof(s));
+
+ /* If an overlong response was received, the data will have been
+ truncated and dn_expand may fail. */
+
+ if (rc < 0)
{
- if (weight < 2) *s = 'N'; /* not authorized */
- else if (weight == 2) *s = 'Y'; /* authorized */
- else if (weight == 3) *s = '?'; /* unauthorizable */
- else continue; /* invalid */
+ log_write(0, LOG_MAIN, "host name alias list truncated: type=%s "
+ "domain=%s", dns_text_type(type), domain);
+ break;
}
-
- s[1] = ' ';
- yield = string_cat(yield, &size, &ptr, s, 2);
+ else yield = string_cat(yield, s);
+
+ if (type == T_SOA && outsep2 != NULL)
+ {
+ unsigned long serial, refresh, retry, expire, minimum;
+
+ p += rc;
+ yield = string_catn(yield, outsep2, 1);
+
+ rc = dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, p,
+ (DN_EXPAND_ARG4_TYPE)s, sizeof(s));
+ if (rc < 0)
+ {
+ log_write(0, LOG_MAIN, "responsible-mailbox truncated: type=%s "
+ "domain=%s", dns_text_type(type), domain);
+ break;
+ }
+ else yield = string_cat(yield, s);
+
+ p += rc;
+ GETLONG(serial, p); GETLONG(refresh, p);
+ GETLONG(retry, p); GETLONG(expire, p); GETLONG(minimum, p);
+ sprintf(CS s, "%c%lu%c%lu%c%lu%c%lu%c%lu",
+ *outsep2, serial, *outsep2, refresh,
+ *outsep2, retry, *outsep2, expire, *outsep2, minimum);
+ yield = string_cat(yield, s);
+ }
}
+ } /* Loop for list of returned records */
- /* GETSHORT() has advanced the pointer to the target domain. */
-
- rc = dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, p,
- (DN_EXPAND_ARG4_TYPE)(s), sizeof(s));
+ /* Loop for set of A-lookup types */
+ } while (type == T_ADDRESSES && searchtype != T_A);
- /* If an overlong response was received, the data will have been
- truncated and dn_expand may fail. */
-
- if (rc < 0)
- {
- log_write(0, LOG_MAIN, "host name alias list truncated: type=%s "
- "domain=%s", dns_text_type(type), domain);
- break;
- }
- else yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
- }
- } /* Loop for list of returned records */
- } /* Loop for list of domains */
+ } /* Loop for list of domains */
/* Reclaim unused memory */
-store_reset(yield + ptr + 1);
+store_reset(yield->s + yield->ptr + 1);
-/* If ptr == 0 we have not found anything. Otherwise, insert the terminating
+/* If yield NULL we have not found anything. Otherwise, insert the terminating
zero and return the result. */
-if (ptr == 0) return failrc;
-yield[ptr] = 0;
-*result = yield;
+dns_retrans = save_retrans;
+dns_retry = save_retry;
+dns_init(FALSE, FALSE, FALSE); /* clear the dnssec bit for getaddrbyname */
+
+if (!yield || !yield->ptr) return failrc;
+
+*result = string_from_gstring(yield);
return OK;
}
static lookup_info *_lookup_list[] = { &_lookup_info };
lookup_module_info dnsdb_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 1 };
+/* vi: aw ai sw=2
+*/
/* End of lookups/dnsdb.c */
git://git.exim.org / exim.git / blobdiff