* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2014 */
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim Maintainers 2020 - 2021 */
/* 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
+# define T_TLSA 52
#endif
/* Table of recognized DNS record types and their integer values. */
#if HAVE_IPV6
"a+",
"aaaa",
- #ifdef SUPPORT_A6
- "a6",
- #endif
#endif
"cname",
"csa",
"mxh",
"ns",
"ptr",
+ "soa",
"spf",
"srv",
"tlsa",
static int type_values[] = {
T_A,
#if HAVE_IPV6
- T_APL, /* Private type for AAAA + A */
+ 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,
/* See local README for interface description. */
static void *
-dnsdb_open(uschar *filename, uschar **errmsg)
+dnsdb_open(const uschar * filename, uschar **errmsg)
{
-filename = filename; /* Keep picky compilers happy */
-errmsg = errmsg; /* Ditto */
return (void *)(-1); /* Any non-0 value */
}
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:
-(d) Another optional comma-sep field: 'dnssec_FOO', with 'strict', 'lax'
-and 'never' (default); can appear before or after (c). The meanings 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' (default), and 'never'. The meanings are
require, try and don't-try dnssec respectively.
-(e) If the next sequence of characters is a sequence of letters and digits
+- '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
default is "TXT".
-(f) Then there follows list of domain names. This is a generalized Exim list,
+(e) Then there follows list of domain names. This is a generalized Exim list,
which may start with '<' in order to set a specific separator. The default
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, const uschar * filename, const uschar * keystring,
+ int length, uschar ** result, uschar ** errmsg, uint * do_cache,
+ const uschar * opts)
{
int rc;
-int size = 256;
-int ptr = 0;
int sep = 0;
int defer_mode = PASS;
-int dnssec_mode = OK;
+int dnssec_mode = PASS;
+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
-store as possible later, so we preallocate the result here */
-
-uschar *yield = store_get(size);
-dns_record *rr;
-dns_answer dnsa;
+dns_answer * dnsa = store_get_dns_answer();
dns_scan dnss;
-handle = handle; /* Keep picky compilers happy */
-filename = filename;
-length = length;
-do_cache = do_cache;
+/* Because we're working in the search pool, we try to reclaim as much
+store as possible later, so we preallocate the result here */
+
+gstring * yield = string_get(256);
/* If the string starts with '>' we change the output separator.
If it's followed by ';' or ',' we set the TXT output separator. */
/* Check for a modifier keyword. */
-while ( strncmpic(keystring, US"defer_", 6) == 0
- || strncmpic(keystring, US"dnssec_", 7) == 0
- )
+for (;;)
{
if (strncmpic(keystring, US"defer_", 6) == 0)
{
keystring += 6;
if (strncmpic(keystring, US"strict", 6) == 0)
- {
- defer_mode = DEFER;
- keystring += 6;
- }
+ { defer_mode = DEFER; keystring += 6; }
else if (strncmpic(keystring, US"lax", 3) == 0)
- {
- defer_mode = PASS;
- keystring += 3;
- }
+ { defer_mode = PASS; keystring += 3; }
else if (strncmpic(keystring, US"never", 5) == 0)
- {
- defer_mode = OK;
- keystring += 5;
- }
+ { defer_mode = OK; keystring += 5; }
else
{
*errmsg = US"unsupported dnsdb defer behaviour";
- return DEFER;
+ rc = DEFER;
+ goto out;
}
}
- else
+ else if (strncmpic(keystring, US"dnssec_", 7) == 0)
{
keystring += 7;
if (strncmpic(keystring, US"strict", 6) == 0)
- {
- dnssec_mode = DEFER;
- keystring += 6;
- }
+ { 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
{
- dnssec_mode = PASS;
- keystring += 3;
+ *errmsg = US"unsupported dnsdb dnssec behaviour";
+ rc = DEFER;
+ goto out;
}
- else if (strncmpic(keystring, US"never", 5) == 0)
+ }
+ else if (strncmpic(keystring, US"retrans_", 8) == 0)
+ {
+ int timeout_sec;
+ if ((timeout_sec = readconf_readtime(keystring += 8, ',', FALSE)) <= 0)
{
- dnssec_mode = OK;
- keystring += 5;
+ *errmsg = US"unsupported dnsdb timeout value";
+ rc = DEFER;
+ goto out;
}
- else
+ dns_retrans = timeout_sec;
+ while (*keystring != ',') keystring++;
+ }
+ else if (strncmpic(keystring, US"retry_", 6) == 0)
+ {
+ int retries;
+ if ((retries = (int)strtol(CCS keystring + 6, CSS &keystring, 0)) < 0)
{
- *errmsg = US"unsupported dnsdb dnssec behaviour";
- return DEFER;
+ *errmsg = US"unsupported dnsdb retry count";
+ rc = DEFER;
+ goto out;
}
+ dns_retry = retries;
}
+ else
+ break;
+
while (isspace(*keystring)) keystring++;
if (*keystring++ != ',')
{
*errmsg = US"dnsdb modifier syntax error";
- return DEFER;
+ rc = DEFER;
+ goto out;
}
while (isspace(*keystring)) keystring++;
}
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;
+ rc = DEFER;
+ goto out;
}
keystring = equals + 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. */
+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 (type == T_SPF && outsep2 == NULL)
- outsep2 = US"";
+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 */
- (type == T_MXH)? T_MX :
- (type == T_ZNS)? T_NS : type;
+ int searchtype = type == T_CSA ? T_SRV : /* record type we want */
+ type == T_MXH ? T_MX :
+ type == T_ZNS ? T_NS : type;
/* If the type is PTR or CSA, we have to construct the relevant magic lookup
key if the original is an IP address (some experimental protocols are using
if ((type == T_PTR || type == T_CSA) &&
string_is_ip_address(domain, NULL) != 0)
- {
- dns_build_reverse(domain, rbuffer);
- domain = rbuffer;
- }
+ domain = dns_build_reverse(domain);
do
{
- DEBUG(D_lookup) debug_printf("dnsdb key: %s\n", domain);
+ DEBUG(D_lookup) debug_printf_indent("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_APL and T_MXH.
+ 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_APL is handled by looping
+ 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
found = domain;
#if HAVE_IPV6
- if (type == T_APL) /* NB cannot happen unless HAVE_IPV6 */
+ if (type == T_ADDRESSES) /* NB cannot happen unless HAVE_IPV6 */
{
- if (searchtype == T_APL)
-# if defined(SUPPORT_A6)
- searchtype = T_A6;
-# else
- searchtype = T_AAAA;
-# endif
- else if (searchtype == T_A6) searchtype = T_AAAA;
+ if (searchtype == T_ADDRESSES) searchtype = T_AAAA;
else if (searchtype == T_AAAA) searchtype = T_A;
- rc = dns_special_lookup(&dnsa, domain, searchtype, &found);
+ rc = dns_special_lookup(dnsa, domain, searchtype, CUSS &found);
}
else
#endif
- rc = dns_special_lookup(&dnsa, domain, type, &found);
+ rc = dns_special_lookup(dnsa, domain, type, CUSS &found);
lookup_dnssec_authenticated = dnssec_mode==OK ? NULL
- : dns_is_secure(&dnsa) ? US"yes" : US"no";
+ : dns_is_secure(dnsa) ? US"yes" : US"no";
if (rc == DNS_NOMATCH || rc == DNS_NODATA) continue;
if ( rc != DNS_SUCCEED
- || dnssec_mode == DEFER && !dns_is_secure(&dnsa)
+ || (dnssec_mode == DEFER && !dns_is_secure(dnsa))
)
{
if (defer_mode == DEFER)
{
+ dns_retrans = save_retrans;
+ dns_retry = save_retry;
dns_init(FALSE, FALSE, FALSE); /* clr dnssec bit */
- return DEFER; /* always defer */
+ rc = DEFER; /* always defer */
+ goto out;
}
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))
+ 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 (rr->type != searchtype) continue;
-
- /* 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. */
-
- if (type == T_A ||
- #ifdef SUPPORT_A6
- type == T_A6 ||
- #endif
- type == T_AAAA ||
- type == T_APL)
+ if (*do_cache > rr->ttl)
+ *do_cache = rr->ttl;
+
+ if (type == T_A || type == T_AAAA || type == T_ADDRESSES)
{
- dns_address *da;
- for (da = dns_address_from_rr(&dnsa, rr); da != NULL; da = da->next)
+ for (dns_address * da = dns_address_from_rr(dnsa, rr); da; 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));
+ if (yield->ptr) yield = string_catn(yield, outsep, 1);
+ yield = string_cat(yield, da->address);
}
continue;
}
/* 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);
+ if (yield->ptr) yield = string_catn(yield, outsep, 1);
if (type == T_TXT || type == T_SPF)
{
- if (outsep2 == NULL)
- {
- /* output only the first item of data */
- yield = string_cat(yield, &size, &ptr, (uschar *)(rr->data+1),
- (rr->data)[0]);
- }
+ 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 */
{
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);
+ 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_TLSA)
{
uint8_t usage, selector, matching_type;
- uint16_t i, payload_length;
+ uint16_t payload_length;
uschar s[MAX_TLSA_EXPANDED_SIZE];
uschar * sp = s;
- uschar *p = (uschar *)(rr->data);
+ 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 %d %d ", usage, selector, matching_type);
+ 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 */
- for (i=0;
- i < payload_length && sp-s < (MAX_TLSA_EXPANDED_SIZE - 4);
- i++)
- {
- sp += sprintf(CS sp, "%02x", (unsigned char)p[i]);
- }
- yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
+ while (payload_length-- > 0 && sp-s < (MAX_TLSA_EXPANDED_SIZE - 4))
+ sp += sprintf(CS sp, "%02x", *p++);
+
+ yield = string_cat(yield, s);
}
- else /* T_CNAME, T_CSA, T_MX, T_MXH, T_NS, T_PTR, T_SRV */
+ else /* T_CNAME, T_CSA, T_MX, T_MXH, T_NS, T_PTR, T_SOA, 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)
- {
- GETSHORT(priority, p);
- sprintf(CS s, "%d ", priority);
- yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
- }
- else if (type == T_SRV)
- {
- 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));
- }
- else if (type == 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 (found != domain)
- {
- 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_cat(yield, &size, &ptr, s, 2);
- }
+ 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));
+ 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. */
"domain=%s", dns_text_type(type), domain);
break;
}
- else yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
+ 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 */
- /* Loop for set of A-lookupu types */
- } while (type == T_APL && searchtype != T_A);
+ /* Loop for set of A-lookup types */
+ } while (type == T_ADDRESSES && searchtype != T_A);
} /* Loop for list of domains */
/* Reclaim unused memory */
-store_reset(yield + ptr + 1);
+gstring_release_unused(yield);
-/* 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. */
+dns_retrans = save_retrans;
+dns_retry = save_retry;
dns_init(FALSE, FALSE, FALSE); /* clear the dnssec bit for getaddrbyname */
-if (ptr == 0) return failrc;
-yield[ptr] = 0;
-*result = yield;
-return OK;
+if (!yield || !yield->ptr)
+ rc = failrc;
+else
+ {
+ *result = string_from_gstring(yield);
+ rc = OK;
+ }
+
+out:
+
+store_free_dns_answer(dnsa);
+return rc;
}
static lookup_info _lookup_info = {
- US"dnsdb", /* lookup name */
- lookup_querystyle, /* query style */
- dnsdb_open, /* open function */
- NULL, /* check function */
- dnsdb_find, /* find function */
- NULL, /* no close function */
- NULL, /* no tidy function */
- NULL, /* no quoting function */
- dnsdb_version_report /* version reporting */
+ .name = US"dnsdb", /* lookup name */
+ .type = lookup_querystyle, /* query style */
+ .open = dnsdb_open, /* open function */
+ .check = NULL, /* check function */
+ .find = dnsdb_find, /* find function */
+ .close = NULL, /* no close function */
+ .tidy = NULL, /* no tidy function */
+ .quote = NULL, /* no quoting function */
+ .version_report = dnsdb_version_report /* version reporting */
};
#ifdef DYNLOOKUP
git://git.exim.org / exim.git / blobdiff