-/* $Cambridge: exim/src/src/lookups/dnsdb.c,v 1.5 2004/11/25 14:31:28 ph10 Exp $ */
+/* $Cambridge: exim/src/src/lookups/dnsdb.c,v 1.13 2005/06/10 13:38:06 tom Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2004 */
+/* Copyright (c) University of Cambridge 1995 - 2005 */
/* See the file NOTICE for conditions of use and distribution. */
#include "../exim.h"
#endif
#endif
"cname",
+ "csa",
"mx",
"mxh",
"ns",
"ptr",
"srv",
"txt",
- "zns"
+ "zns"
};
static int type_values[] = {
#endif
#endif
T_CNAME,
+ T_CSA, /* Private type for "Client SMTP Authorization". */
T_MX,
T_MXH, /* Private type for "MX hostnames" */
T_NS,
/* 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".
+(b) 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) 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
+(c) 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".
+
+(d) 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
int size = 256;
int ptr = 0;
int sep = 0;
+int defer_mode = PASS;
int type = T_TXT;
int failrc = FAIL;
uschar *outsep = US"\n";
-uschar *equals, *domain;
+uschar *equals, *domain, *found;
uschar buffer[256];
/* Because we're the working in the search pool, we try to reclaim as much
if (*keystring == '>')
{
outsep = keystring + 1;
- keystring += 2;
+ keystring += 2;
+ 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. */
{
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;
/* 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
+
+ /* 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
+ 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);
-
+
+ found = domain;
+ rc = dns_special_lookup(&dnsa, domain, type, &found);
+
if (rc == DNS_NOMATCH || rc == DNS_NODATA) continue;
if (rc != DNS_SUCCEED)
{
- failrc = DEFER;
- continue;
+ 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 = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
{
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
+
+ /* 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 ||
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,
+ yield = string_cat(yield, &size, &ptr, da->address,
Ustrlen(da->address));
}
continue;
}
-
- /* Other kinds of record just have one piece of data each, but there may be
+
+ /* 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)
{
yield = string_cat(yield, &size, &ptr, (uschar *)(rr->data+1),
(rr->data)[0]);
}
- else /* T_CNAME, T_MX, T_MXH, T_NS, T_SRV, T_PTR */
+ else /* T_CNAME, T_CSA, T_MX, T_MXH, T_NS, T_PTR, T_SRV */
{
- int num;
+ 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(num, p); /* pointer is advanced */
+ GETSHORT(priority, p);
}
else if (type == T_MX)
{
- GETSHORT(num, p); /* pointer is advanced */
- sprintf(CS s, "%d ", num);
+ GETSHORT(priority, p);
+ sprintf(CS s, "%d ", priority);
yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
}
else if (type == T_SRV)
{
- int weight, port;
- GETSHORT(num, p); /* pointer is advanced */
+ GETSHORT(priority, p);
GETSHORT(weight, p);
GETSHORT(port, p);
- sprintf(CS s, "%d %d %d ", num, weight, port);
+ 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 "
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;
projects / exim.git / blobdiff