-/* $Cambridge: exim/src/src/lookups/dnsdb.c,v 1.5 2004/11/25 14:31:28 ph10 Exp $ */
-
/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2004 */
+/* Copyright (c) University of Cambridge 1995 - 2012 */
/* See the file NOTICE for conditions of use and distribution. */
#include "../exim.h"
#include "lf_functions.h"
-#include "dnsdb.h"
#define T_TXT 16
#endif
+/* Many systems do not have T_SPF. */
+#ifndef T_SPF
+#define T_SPF 99
+#endif
+
/* Table of recognized DNS record types and their integer values. */
-static char *type_names[] = {
+static const char *type_names[] = {
"a",
#if HAVE_IPV6
+ "a+",
"aaaa",
#ifdef SUPPORT_A6
"a6",
#endif
#endif
"cname",
+ "csa",
"mx",
"mxh",
"ns",
"ptr",
+ "spf",
"srv",
"txt",
- "zns"
+ "zns"
};
static int type_values[] = {
T_A,
#if HAVE_IPV6
+ T_APL, /* 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_MX,
T_MXH, /* Private type for "MX hostnames" */
T_NS,
T_PTR,
+ T_SPF,
T_SRV,
T_TXT,
T_ZNS /* Private type for "zone nameservers" */
/* See local README for interface description. */
-void *
+static void *
dnsdb_open(uschar *filename, uschar **errmsg)
{
filename = filename; /* Keep picky compilers happy */
/* See local README for interface description. The query in the "keystring" may
consist of a number of parts.
-(a) If the first significant character is '>' then the next character is the
-separator character that is used when multiple records are found. The default
+(a) If the first significant character is '>' then the next character is the
+separator character that is used when multiple records are found. The default
separator is newline.
-(b) 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 "A".
-
-(c) 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
+(b) If the next character is ',' then the next character is the separator
+character used for multiple items of text in "TXT" records. Alternatively,
+if the next character is ';' then these multiple items are concatenated with
+no separator. With neither of these options specified, only the first item
+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'.
+
+(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".
+
+(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. */
-int
+static int
dnsdb_find(void *handle, uschar *filename, uschar *keystring, int length,
uschar **result, uschar **errmsg, BOOL *do_cache)
{
int size = 256;
int ptr = 0;
int sep = 0;
-int type = T_TXT;
+int defer_mode = PASS;
+int type;
int failrc = FAIL;
uschar *outsep = US"\n";
-uschar *equals, *domain;
+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
length = length;
do_cache = do_cache;
-/* If the string starts with '>' we change the output separator */
+/* If the string starts with '>' we change the output separator.
+If it's followed by ';' or ',' we set the TXT output separator. */
while (isspace(*keystring)) keystring++;
if (*keystring == '>')
{
outsep = keystring + 1;
- keystring += 2;
+ keystring += 2;
+ if (*keystring == ',')
+ {
+ outsep2 = keystring + 1;
+ keystring += 2;
+ }
+ else if (*keystring == ';')
+ {
+ outsep2 = US"";
+ keystring++;
+ }
+ while (isspace(*keystring)) keystring++;
+ }
+
+/* Check for a defer behaviour keyword. */
+
+if (strncmpic(keystring, US"defer_", 6) == 0)
+ {
+ 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;
+ }
while (isspace(*keystring)) keystring++;
- }
+ if (*keystring++ != ',')
+ {
+ *errmsg = US"dnsdb defer behaviour 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;
uschar *tend = equals;
-
- while (tend > keystring && isspace(tend[-1])) tend--;
- len = tend - keystring;
-
+
+ while (tend > keystring && isspace(tend[-1])) tend--;
+ len = tend - keystring;
+
for (i = 0; i < sizeof(type_names)/sizeof(uschar *); i++)
{
if (len == Ustrlen(type_names[i]) &&
break;
}
}
-
+
if (i >= sizeof(type_names)/sizeof(uschar *))
{
*errmsg = US"unsupported DNS record type";
return DEFER;
}
-
+
keystring = equals + 1;
while (isspace(*keystring)) keystring++;
}
-
+
/* Initialize the resolver in case this is the first time it has been used. */
dns_init(FALSE, FALSE);
-/* 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
-of them were found.
+/* 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
+of them were found.
-The original implementation did not support a list of domains. Adding the list
-feature is compatible, except in one case: when PTR records are being looked up
-for a single IPv6 address. Fortunately, we can hack in a compatibility feature
-here: If the type is PTR and no list separator is specified, and the entire
-remaining string is valid as an IP address, set an impossible separator so that
+The original implementation did not support a list of domains. Adding the list
+feature is compatible, except in one case: when PTR records are being looked up
+for a single IPv6 address. Fortunately, we can hack in a compatibility feature
+here: If the type is PTR and no list separator is specified, and the entire
+remaining string is valid as an IP address, set an impossible separator so that
it is treated as one item. */
if (type == T_PTR && keystring[0] != '<' &&
- string_is_ip_address(keystring, NULL) > 0)
+ 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. */
+
+if (type == T_SPF && outsep2 == NULL)
+ outsep2 = US"";
+
/* Now scan the list and do a lookup for each item */
-while ((domain = string_nextinlist(&keystring, &sep, buffer, sizeof(buffer)))
+while ((domain = string_nextinlist(&keystring, &sep, buffer, sizeof(buffer)))
!= NULL)
- {
+ {
uschar rbuffer[256];
- int searchtype = (type == T_ZNS)? T_NS : /* record type we want */
- (type == T_MXH)? T_MX : type;
-
- /* If the type is PTR, we have to construct the relevant magic lookup
- key. This code is now in a separate function. */
-
- if (type == T_PTR)
+ 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
+ PTR records for different purposes where the key string is a host name, and
+ Exim's extended CSA can be keyed by domains or IP addresses). This code for
+ doing the reversal is now in a separate function. */
+
+ if ((type == T_PTR || type == T_CSA) &&
+ string_is_ip_address(domain, NULL) != 0)
{
dns_build_reverse(domain, rbuffer);
domain = rbuffer;
}
-
- DEBUG(D_lookup) debug_printf("dnsdb key: %s\n", domain);
-
- /* Do the lookup and sort out the result. There are two special types that
- are handled specially: T_ZNS and T_MXH. The former is 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. */
-
- rc = dns_special_lookup(&dnsa, domain, type, NULL);
-
- if (rc == DNS_NOMATCH || rc == DNS_NODATA) continue;
- if (rc != DNS_SUCCEED)
- {
- failrc = DEFER;
- continue;
- }
-
- /* 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;
-
- /* 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)
+ 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_APL 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
+ 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_APL) /* NB cannot happen unless HAVE_IPV6 */
{
- 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 (searchtype == T_APL)
+# if defined(SUPPORT_A6)
+ searchtype = T_A6;
+# else
+ searchtype = T_AAAA;
+# endif
+ else if (searchtype == T_A6) searchtype = T_AAAA;
+ else if (searchtype == T_AAAA) searchtype = T_A;
+ rc = dns_special_lookup(&dnsa, domain, searchtype, &found);
}
-
- /* 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 (type == T_TXT)
+ else
+#endif
+ rc = dns_special_lookup(&dnsa, domain, type, &found);
+
+ if (rc == DNS_NOMATCH || rc == DNS_NODATA) continue;
+ if (rc != DNS_SUCCEED)
{
- yield = string_cat(yield, &size, &ptr, (uschar *)(rr->data+1),
- (rr->data)[0]);
+ if (defer_mode == DEFER) return DEFER; /* always defer */
+ if (defer_mode == PASS) failrc = DEFER; /* defer only if all do */
+ continue; /* treat defer as fail */
}
- else /* T_CNAME, T_MX, T_MXH, T_NS, T_SRV, T_PTR */
+
+ /* Search the returned records */
+
+ for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
+ rr != NULL;
+ rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
{
- int num;
- uschar s[264];
- uschar *p = (uschar *)(rr->data);
-
- if (type == T_MXH)
+ 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)
{
- /* mxh ignores the priority number and includes only the hostnames */
- GETSHORT(num, p); /* pointer is advanced */
+ 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;
}
- else if (type == T_MX)
- {
- GETSHORT(num, p); /* pointer is advanced */
- sprintf(CS s, "%d ", num);
- yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
- }
- else if (type == T_SRV)
+
+ /* 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 (type == T_TXT || type == T_SPF)
{
- int weight, port;
- GETSHORT(num, p); /* pointer is advanced */
- GETSHORT(weight, p);
- GETSHORT(port, p);
- sprintf(CS s, "%d %d %d ", num, weight, port);
- yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
+ if (outsep2 == NULL)
+ {
+ /* output only the first item of data */
+ yield = string_cat(yield, &size, &ptr, (uschar *)(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_cat(yield, &size, &ptr, outsep2, 1);
+ yield = string_cat(yield, &size, &ptr,
+ (uschar *)((rr->data)+data_offset), chunk_len);
+ data_offset += chunk_len;
+ }
+ }
}
-
- 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)
+ else /* T_CNAME, T_CSA, T_MX, T_MXH, T_NS, T_PTR, T_SRV */
{
- log_write(0, LOG_MAIN, "host name alias list truncated: type=%s "
- "domain=%s", dns_text_type(type), domain);
- break;
+ 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);
+ }
+
+ /* 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)
+ {
+ 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));
}
- 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 returned records */
+
+ /* Loop for set of A-lookupu types */
+ } while (type == T_APL && searchtype != T_A);
+
+ } /* Loop for list of domains */
/* Reclaim unused memory */
store_reset(yield + ptr + 1);
-/* If ptr == 0 we have not found anything. Otherwise, insert the terminating
+/* If ptr == 0 we have not found anything. Otherwise, insert the terminating
zero and return the result. */
if (ptr == 0) return failrc;
return OK;
}
+
+
+/*************************************************
+* Version reporting entry point *
+*************************************************/
+
+/* See local README for interface description. */
+
+#include "../version.h"
+
+void
+dnsdb_version_report(FILE *f)
+{
+#ifdef DYNLOOKUP
+fprintf(f, "Library version: DNSDB: Exim version %s\n", EXIM_VERSION_STR);
+#endif
+}
+
+
+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 */
+};
+
+#ifdef DYNLOOKUP
+#define dnsdb_lookup_module_info _lookup_module_info
+#endif
+
+static lookup_info *_lookup_list[] = { &_lookup_info };
+lookup_module_info dnsdb_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 1 };
+
/* End of lookups/dnsdb.c */
git://git.exim.org / users / jgh / exim.git / blobdiff