2. Apply Tony's CSA patch (with some fixes) and add simple test.
-$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.133 2005/05/04 10:17:28 ph10 Exp $
+$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.134 2005/05/10 10:19:11 ph10 Exp $
Change log file for Exim from version 4.21
-------------------------------------------
+Exim version 4.52
+-----------------
+
+TF/01 Added support for Client SMTP Authorization. See NewStuff for details.
+
+
Exim version 4.51
-----------------
-$Cambridge: exim/doc/doc-txt/NewStuff,v 1.39 2005/05/03 14:20:00 ph10 Exp $
+$Cambridge: exim/doc/doc-txt/NewStuff,v 1.40 2005/05/10 10:19:11 ph10 Exp $
New Features in Exim
--------------------
file contains a listing of all changes, including bug fixes.
+Exim version 4.52
+-----------------
+
+TF/01 Support for checking Client SMTP Authorization has been added. CSA is a
+ system which allows a site to advertise which machines are and are not
+ permitted to send email. This is done by placing special SRV records in
+ the DNS, which are looked up using the client's HELO domain. At this
+ time CSA is still an Internet-Draft.
+
+ Client SMTP Authorization checks are performed by the ACL condition
+ verify=csa. This will fail if the client is not authorized. If there is
+ a DNS problem, or if no valid CSA SRV record is found, or if the client
+ is authorized, the condition succeeds. These three cases can be
+ distinguished using the expansion variable $csa_status, which can take
+ one of the values "fail", "defer", "unknown", or "ok". The condition
+ does not itself defer because that would be likely to cause problems
+ for legitimate email.
+
+ The error messages produced by the CSA code include slightly more
+ detail. If $csa_status is "defer" this may be because of problems
+ looking up the CSA SRV record, or problems looking up the CSA target
+ address record. There are four reasons for $csa_status being "fail":
+ the client's host name is explicitly not authorized; the client's IP
+ address does not match any of the CSA target IP addresses; the client's
+ host name is authorized but it has no valid target IP addresses (e.g.
+ the target's addresses are IPv6 and the client is using IPv4); or the
+ client's host name has no CSA SRV record but a parent domain has
+ asserted that all subdomains must be explicitly authorized.
+
+ The verify=csa condition can take an argument which is the domain to
+ use for the DNS query. The default is verify=csa/$sender_helo_name.
+
+ This implementation includes an extension to CSA. If the query domain
+ is an address literal such as [192.0.2.95], or if it is a bare IP
+ address, Exim will search for CSA SRV records in the reverse DNS as if
+ the HELO domain was e.g. 95.2.0.192.in-addr.arpa. Therefore it is
+ meaningful to say, for example, verify=csa/$sender_host_address - in
+ fact, this is the check that Exim performs if the client does not say
+ HELO. This extension can be turned off by setting the main
+ configuration option dns_csa_use_reverse = false.
+
+ If a CSA SRV record is not found for the domain itself, then a search
+ is performed through its parent domains for a record which might be
+ making assertions about subdomains. The maximum depth of this search is
+ limited using the main configuration option dns_csa_search_limit, which
+ takes the value 5 by default. Exim does not look for CSA SRV records in
+ a top level domain, so the default settings handle HELO domains as long
+ as seven (hostname.five.four.three.two.one.com) which encompasses the
+ vast majority of legitimate HELO domains.
+
+ The dnsdb lookup also has support for CSA. Although dnsdb already
+ supports SRV lookups, this is not sufficient because of the extra
+ parent domain search behaviour of CSA, and (as with PTR lookups)
+ dnsdb also turns IP addresses into lookups in the reverse DNS space.
+ The result of ${lookup dnsdb {csa=$sender_helo_name} } has two
+ space-separated fields: an authorization code and a target host name.
+ The authorization code can be "Y" for yes, "N" for no, "X" for explicit
+ authorization required but absent, or "?" for unknown.
+
+
Version 4.51
------------
-/* $Cambridge: exim/src/src/acl.c,v 1.28 2005/04/06 14:03:53 ph10 Exp $ */
+/* $Cambridge: exim/src/src/acl.c,v 1.29 2005/05/10 10:19:11 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
{ US"submission", CONTROL_SUBMISSION, TRUE}
};
+/* Support data structures for Client SMTP Authorization. acl_verify_csa()
+caches its result in a tree to avoid repeated DNS queries. The result is an
+integer code which is used as an index into the following tables of
+explanatory strings and verification return codes. */
+
+static tree_node *csa_cache = NULL;
+
+enum { CSA_UNKNOWN, CSA_OK, CSA_DEFER_SRV, CSA_DEFER_ADDR,
+ CSA_FAIL_EXPLICIT, CSA_FAIL_DOMAIN, CSA_FAIL_NOADDR, CSA_FAIL_MISMATCH };
+
+/* The acl_verify_csa() return code is translated into an acl_verify() return
+code using the following table. It is OK unless the client is definitely not
+authorized. This is because CSA is supposed to be optional for sending sites,
+so recipients should not be too strict about checking it - especially because
+DNS problems are quite likely to occur. It's possible to use $csa_status in
+further ACL conditions to distinguish ok, unknown, and defer if required, but
+the aim is to make the usual configuration simple. */
+
+static int csa_return_code[] = {
+ OK, OK, OK, OK,
+ FAIL, FAIL, FAIL, FAIL
+};
+
+static uschar *csa_status_string[] = {
+ US"unknown", US"ok", US"defer", US"defer",
+ US"fail", US"fail", US"fail", US"fail"
+};
+
+static uschar *csa_reason_string[] = {
+ US"unknown",
+ US"ok",
+ US"deferred (SRV lookup failed)",
+ US"deferred (target address lookup failed)",
+ US"failed (explicit authorization required)",
+ US"failed (host name not authorized)",
+ US"failed (no authorized addresses)",
+ US"failed (client address mismatch)"
+};
+
/* Enable recursion between acl_check_internal() and acl_check_condition() */
static int acl_check_internal(int, address_item *, uschar *, int, uschar **,
+/*************************************************
+* Check client IP address matches CSA target *
+*************************************************/
+
+/* Called from acl_verify_csa() below. This routine scans a section of a DNS
+response for address records belonging to the CSA target hostname. The section
+is specified by the reset argument, either RESET_ADDITIONAL or RESET_ANSWERS.
+If one of the addresses matches the client's IP address, then the client is
+authorized by CSA. If there are target IP addresses but none of them match
+then the client is using an unauthorized IP address. If there are no target IP
+addresses then the client cannot be using an authorized IP address. (This is
+an odd configuration - why didn't the SRV record have a weight of 1 instead?)
+
+Arguments:
+ dnsa the DNS answer block
+ dnss a DNS scan block for us to use
+ reset option specifing what portion to scan, as described above
+ target the target hostname to use for matching RR names
+
+Returns: CSA_OK successfully authorized
+ CSA_FAIL_MISMATCH addresses found but none matched
+ CSA_FAIL_NOADDR no target addresses found
+*/
+
+static int
+acl_verify_csa_address(dns_answer *dnsa, dns_scan *dnss, int reset,
+ uschar *target)
+{
+dns_record *rr;
+dns_address *da;
+
+BOOL target_found = FALSE;
+
+for (rr = dns_next_rr(dnsa, dnss, reset);
+ rr != NULL;
+ rr = dns_next_rr(dnsa, dnss, RESET_NEXT))
+ {
+ /* Check this is an address RR for the target hostname. */
+
+ if (rr->type != T_A
+ #if HAVE_IPV6
+ && rr->type != T_AAAA
+ #ifdef SUPPORT_A6
+ && rr->type != T_A6
+ #endif
+ #endif
+ ) continue;
+
+ if (strcmpic(target, rr->name) != 0) continue;
+
+ target_found = TRUE;
+
+ /* Turn the target address RR into a list of textual IP addresses and scan
+ the list. There may be more than one if it is an A6 RR. */
+
+ for (da = dns_address_from_rr(dnsa, rr); da != NULL; da = da->next)
+ {
+ /* If the client IP address matches the target IP address, it's good! */
+
+ DEBUG(D_acl) debug_printf("CSA target address is %s\n", da->address);
+
+ if (strcmpic(sender_host_address, da->address) == 0) return CSA_OK;
+ }
+ }
+
+/* If we found some target addresses but none of them matched, the client is
+using an unauthorized IP address, otherwise the target has no authorized IP
+addresses. */
+
+if (target_found) return CSA_FAIL_MISMATCH;
+else return CSA_FAIL_NOADDR;
+}
+
+
+
+/*************************************************
+* Verify Client SMTP Authorization *
+*************************************************/
+
+/* Called from acl_verify() below. This routine calls dns_lookup_special()
+to find the CSA SRV record corresponding to the domain argument, or
+$sender_helo_name if no argument is provided. It then checks that the
+client is authorized, and that its IP address corresponds to the SRV
+target's address by calling acl_verify_csa_address() above. The address
+should have been returned in the DNS response's ADDITIONAL section, but if
+not we perform another DNS lookup to get it.
+
+Arguments:
+ domain pointer to optional parameter following verify = csa
+
+Returns: CSA_UNKNOWN no valid CSA record found
+ CSA_OK successfully authorized
+ CSA_FAIL_* client is definitely not authorized
+ CSA_DEFER_* there was a DNS problem
+*/
+
+static int
+acl_verify_csa(uschar *domain)
+{
+tree_node *t;
+uschar *found, *p;
+int priority, weight, port;
+dns_answer dnsa;
+dns_scan dnss;
+dns_record *rr;
+int rc, type;
+uschar target[256];
+
+/* Work out the domain we are using for the CSA lookup. The default is the
+client's HELO domain. If the client has not said HELO, use its IP address
+instead. If it's a local client (exim -bs), CSA isn't applicable. */
+
+while (isspace(*domain) && *domain != '\0') ++domain;
+if (*domain == '\0') domain = sender_helo_name;
+if (domain == NULL) domain = sender_host_address;
+if (sender_host_address == NULL) return CSA_UNKNOWN;
+
+/* If we have an address literal, strip off the framing ready for turning it
+into a domain. The framing consists of matched square brackets possibly
+containing a keyword and a colon before the actual IP address. */
+
+if (domain[0] == '[')
+ {
+ uschar *start = Ustrchr(domain, ':');
+ if (start == NULL) start = domain;
+ domain = string_copyn(start + 1, Ustrlen(start) - 2);
+ }
+
+/* Turn domains that look like bare IP addresses into domains in the reverse
+DNS. This code also deals with address literals and $sender_host_address. It's
+not quite kosher to treat bare domains such as EHLO 192.0.2.57 the same as
+address literals, but it's probably the most friendly thing to do. This is an
+extension to CSA, so we allow it to be turned off for proper conformance. */
+
+if (string_is_ip_address(domain, NULL))
+ {
+ if (!dns_csa_use_reverse) return CSA_UNKNOWN;
+ dns_build_reverse(domain, target);
+ domain = target;
+ }
+
+/* Find out if we've already done the CSA check for this domain. If we have,
+return the same result again. Otherwise build a new cached result structure
+for this domain. The name is filled in now, and the value is filled in when
+we return from this function. */
+
+t = tree_search(csa_cache, domain);
+if (t != NULL) return t->data.val;
+
+t = store_get_perm(sizeof(tree_node) + Ustrlen(domain));
+Ustrcpy(t->name, domain);
+(void)tree_insertnode(&csa_cache, t);
+
+/* Now we are ready to do the actual DNS lookup(s). */
+
+switch (dns_special_lookup(&dnsa, domain, T_CSA, &found))
+ {
+ /* If something bad happened (most commonly DNS_AGAIN), defer. */
+
+ default:
+ return t->data.val = CSA_DEFER_SRV;
+
+ /* If we found nothing, the client's authorization is unknown. */
+
+ case DNS_NOMATCH:
+ case DNS_NODATA:
+ return t->data.val = CSA_UNKNOWN;
+
+ /* We got something! Go on to look at the reply in more detail. */
+
+ case DNS_SUCCEED:
+ break;
+ }
+
+/* Scan the reply for well-formed CSA SRV records. */
+
+for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
+ rr != NULL;
+ rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
+ {
+ if (rr->type != T_SRV) continue;
+
+ /* Extract the numerical SRV fields (p is incremented) */
+
+ p = rr->data;
+ GETSHORT(priority, p);
+ GETSHORT(weight, p);
+ GETSHORT(port, p);
+
+ DEBUG(D_acl)
+ debug_printf("CSA priority=%d weight=%d port=%d\n", priority, weight, port);
+
+ /* Check the CSA version number */
+
+ if (priority != 1) continue;
+
+ /* If the domain does not have a CSA SRV record of its own (i.e. the domain
+ found by dns_special_lookup() is a parent of the one we asked for), we check
+ the subdomain assertions in the port field. At the moment there's only one
+ assertion: legitimate SMTP clients are all explicitly authorized with CSA
+ SRV records of their own. */
+
+ if (found != domain)
+ {
+ if (port & 1)
+ return t->data.val = CSA_FAIL_EXPLICIT;
+ else
+ return t->data.val = CSA_UNKNOWN;
+ }
+
+ /* This CSA SRV record refers directly to our domain, so we check the value
+ in the weight field to work out the domain's authorization. 0 and 1 are
+ unauthorized; 3 means the client is authorized but we can't check the IP
+ address in order to authenticate it, so we treat it as unknown; values
+ greater than 3 are undefined. */
+
+ if (weight < 2) return t->data.val = CSA_FAIL_DOMAIN;
+
+ if (weight > 2) continue;
+
+ /* Weight == 2, which means the domain is authorized. We must check that the
+ client's IP address is listed as one of the SRV target addresses. Save the
+ target hostname then break to scan the additional data for its addresses. */
+
+ (void)dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, p,
+ (DN_EXPAND_ARG4_TYPE)target, sizeof(target));
+
+ DEBUG(D_acl) debug_printf("CSA target is %s\n", target);
+
+ break;
+ }
+
+/* If we didn't break the loop then no appropriate records were found. */
+
+if (rr == NULL) return t->data.val = CSA_UNKNOWN;
+
+/* Do not check addresses if the target is ".", in accordance with RFC 2782.
+A target of "." indicates there are no valid addresses, so the client cannot
+be authorized. (This is an odd configuration because weight=2 target=. is
+equivalent to weight=1, but we check for it in order to keep load off the
+root name servers.) Note that dn_expand() turns "." into "". */
+
+if (Ustrcmp(target, "") == 0) return t->data.val = CSA_FAIL_NOADDR;
+
+/* Scan the additional section of the CSA SRV reply for addresses belonging
+to the target. If the name server didn't return any additional data (e.g.
+because it does not fully support SRV records), we need to do another lookup
+to obtain the target addresses; otherwise we have a definitive result. */
+
+rc = acl_verify_csa_address(&dnsa, &dnss, RESET_ADDITIONAL, target);
+if (rc != CSA_FAIL_NOADDR) return t->data.val = rc;
+
+/* The DNS lookup type corresponds to the IP version used by the client. */
+
+#if HAVE_IPV6
+if (Ustrchr(sender_host_address, ':') != NULL)
+ type = T_AAAA;
+else
+#endif /* HAVE_IPV6 */
+ type = T_A;
+
+
+#if HAVE_IPV6 && defined(SUPPORT_A6)
+DNS_LOOKUP_AGAIN:
+#endif
+
+switch (dns_lookup(&dnsa, target, type, NULL))
+ {
+ /* If something bad happened (most commonly DNS_AGAIN), defer. */
+
+ default:
+ return t->data.val = CSA_DEFER_ADDR;
+
+ /* If the query succeeded, scan the addresses and return the result. */
+
+ case DNS_SUCCEED:
+ rc = acl_verify_csa_address(&dnsa, &dnss, RESET_ANSWERS, target);
+ if (rc != CSA_FAIL_NOADDR) return t->data.val = rc;
+ /* else fall through */
+
+ /* If the target has no IP addresses, the client cannot have an authorized
+ IP address. However, if the target site uses A6 records (not AAAA records)
+ we have to do yet another lookup in order to check them. */
+
+ case DNS_NOMATCH:
+ case DNS_NODATA:
+
+ #if HAVE_IPV6 && defined(SUPPORT_A6)
+ if (type == T_AAAA) { type = T_A6; goto DNS_LOOKUP_AGAIN; }
+ #endif
+
+ return t->data.val = CSA_FAIL_NOADDR;
+ }
+}
+
+
+
/*************************************************
* Handle verification (address & other) *
*************************************************/
return helo_verified? OK : FAIL;
}
+/* Do Client SMTP Authorization checks in a separate function, and turn the
+result code into user-friendly strings. */
+
+if (strcmpic(ss, US"csa") == 0)
+ {
+ rc = acl_verify_csa(list);
+ *log_msgptr = *user_msgptr = string_sprintf("client SMTP authorization %s",
+ csa_reason_string[rc]);
+ csa_status = csa_status_string[rc];
+ DEBUG(D_acl) debug_printf("CSA result %s\n", csa_status);
+ return csa_return_code[rc];
+ }
+
/* Check that all relevant header lines have the correct syntax. If there is
a syntax error, we return details of the error to the sender if configured to
send out full details. (But a "message" setting on the ACL can override, as
-/* $Cambridge: exim/src/src/dns.c,v 1.5 2005/02/17 11:58:26 ph10 Exp $ */
+/* $Cambridge: exim/src/src/dns.c,v 1.6 2005/05/10 10:19:11 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
/* Call this with reset == RESET_ANSWERS to scan the answer block, reset ==
-RESET_ADDITIONAL to scan the additional records, and reset == RESET_NEXT to
-get the next record. The result is in static storage which must be copied if
-it is to be preserved.
+RESET_AUTHORITY to scan the authority records, reset == RESET_ADDITIONAL to
+scan the additional records, and reset == RESET_NEXT to get the next record.
+The result is in static storage which must be copied if it is to be preserved.
Arguments:
dnsa pointer to dns answer block
dnss->rrcount = ntohs(h->ancount);
- /* Skip over answers and NS records if wanting to look at the additional
+ /* Skip over answers if we want to look at the authority section. Also skip
+ the NS records (i.e. authority section) if wanting to look at the additional
records. */
- if (reset == RESET_ADDITIONAL)
+ if (reset == RESET_ADDITIONAL) dnss->rrcount += ntohs(h->nscount);
+
+ if (reset == RESET_AUTHORITY || reset == RESET_ADDITIONAL)
{
- dnss->rrcount += ntohs(h->nscount);
while (dnss->rrcount-- > 0)
{
namelen = dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen,
GETSHORT(dnss->srr.size, dnss->aptr); /* size of data portion */
dnss->aptr += dnss->srr.size; /* skip over it */
}
- dnss->rrcount = ntohs(h->arcount);
+ dnss->rrcount = (reset == RESET_AUTHORITY)
+ ? ntohs(h->nscount) : ntohs(h->arcount);
}
}
-
/* The variable dnss->aptr is now pointing at the next RR, and dnss->rrcount
contains the number of RR records left. */
return DNS_NOMATCH;
}
+/* Try to look up the Client SMTP Authorization SRV record for the name. If
+there isn't one, search from the top downwards for a CSA record in a parent
+domain, which might be making assertions about subdomains. If we find a record
+we set fully_qualified_name to whichever lookup succeeded, so that the caller
+can tell whether to look at the explicit authorization field or the subdomain
+assertion field. */
+
+if (type == T_CSA)
+ {
+ uschar *srvname, *namesuff, *tld, *p;
+ int priority, weight, port;
+ int limit, rc, i;
+ BOOL ipv6;
+ dns_record *rr;
+ dns_scan dnss;
+
+ DEBUG(D_dns) debug_printf("CSA lookup of %s\n", name);
+
+ srvname = string_sprintf("_client._smtp.%s", name);
+ rc = dns_lookup(dnsa, srvname, T_SRV, NULL);
+ if (rc == DNS_SUCCEED || rc == DNS_AGAIN)
+ {
+ if (rc == DNS_SUCCEED) *fully_qualified_name = name;
+ return rc;
+ }
+
+ /* Search for CSA subdomain assertion SRV records from the top downwards,
+ starting with the 2nd level domain. This order maximizes cache-friendliness.
+ We skip the top level domains to avoid loading their nameservers and because
+ we know they'll never have CSA SRV records. */
+
+ namesuff = Ustrrchr(name, '.');
+ if (namesuff == NULL) return DNS_NOMATCH;
+ tld = namesuff + 1;
+ ipv6 = FALSE;
+ limit = dns_csa_search_limit;
+
+ /* Use more appropriate search parameters if we are in the reverse DNS. */
+
+ if (strcmpic(namesuff, US".arpa") == 0)
+ {
+ if (namesuff - 8 > name && strcmpic(namesuff - 8, US".in-addr.arpa") == 0)
+ {
+ namesuff -= 8;
+ tld = namesuff + 1;
+ limit = 3;
+ }
+ else if (namesuff - 4 > name && strcmpic(namesuff - 4, US".ip6.arpa") == 0)
+ {
+ namesuff -= 4;
+ tld = namesuff + 1;
+ ipv6 = TRUE;
+ limit = 3;
+ }
+ }
+
+ DEBUG(D_dns) debug_printf("CSA TLD %s\n", tld);
+
+ /* Do not perform the search if the top level or 2nd level domains do not
+ exist. This is quite common, and when it occurs all the search queries would
+ go to the root or TLD name servers, which is not friendly. So we check the
+ AUTHORITY section; if it contains the root's SOA record or the TLD's SOA then
+ the TLD or the 2LD (respectively) doesn't exist and we can skip the search.
+ If the TLD and the 2LD exist but the explicit CSA record lookup failed, then
+ the AUTHORITY SOA will be the 2LD's or a subdomain thereof. */
+
+ if (rc == DNS_NOMATCH)
+ {
+ /* This is really gross. The successful return value from res_search() is
+ the packet length, which is stored in dnsa->answerlen. If we get a
+ negative DNS reply then res_search() returns -1, which causes the bounds
+ checks for name decompression to fail when it is treated as a packet
+ length, which in turn causes the authority search to fail. The correct
+ packet length has been lost inside libresolv, so we have to guess a
+ replacement value. (The only way to fix this properly would be to
+ re-implement res_search() and res_query() so that they don't muddle their
+ success and packet length return values.) For added safety we only reset
+ the packet length if the packet header looks plausible. */
+
+ HEADER *h = (HEADER *)dnsa->answer;
+ if (h->qr == 1 && h->opcode == QUERY && h->tc == 0
+ && (h->rcode == NOERROR || h->rcode == NXDOMAIN)
+ && ntohs(h->qdcount) == 1 && ntohs(h->ancount) == 0
+ && ntohs(h->nscount) >= 1)
+ dnsa->answerlen = MAXPACKET;
+
+ for (rr = dns_next_rr(dnsa, &dnss, RESET_AUTHORITY);
+ rr != NULL;
+ rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
+ if (rr->type != T_SOA) continue;
+ else if (strcmpic(rr->name, US"") == 0 ||
+ strcmpic(rr->name, tld) == 0) return DNS_NOMATCH;
+ else break;
+ }
+
+ for (i = 0; i < limit; i++)
+ {
+ if (ipv6)
+ {
+ /* Scan through the IPv6 reverse DNS in chunks of 16 bits worth of IP
+ address, i.e. 4 hex chars and 4 dots, i.e. 8 chars. */
+ namesuff -= 8;
+ if (namesuff <= name) return DNS_NOMATCH;
+ }
+ else
+ /* Find the start of the preceding domain name label. */
+ do
+ if (--namesuff <= name) return DNS_NOMATCH;
+ while (*namesuff != '.');
+
+ DEBUG(D_dns) debug_printf("CSA parent search at %s\n", namesuff + 1);
+
+ srvname = string_sprintf("_client._smtp.%s", namesuff + 1);
+ rc = dns_lookup(dnsa, srvname, T_SRV, NULL);
+ if (rc == DNS_AGAIN) return rc;
+ if (rc != DNS_SUCCEED) continue;
+
+ /* Check that the SRV record we have found is worth returning. We don't
+ just return the first one we find, because some lower level SRV record
+ might make stricter assertions than its parent domain. */
+
+ for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
+ rr != NULL;
+ rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
+ {
+ if (rr->type != T_SRV) continue;
+
+ /* Extract the numerical SRV fields (p is incremented) */
+ p = rr->data;
+ GETSHORT(priority, p);
+ GETSHORT(weight, p);
+ GETSHORT(port, p);
+
+ /* Check the CSA version number */
+ if (priority != 1) continue;
+
+ /* If it's making an interesting assertion, return this response. */
+ if (port & 1)
+ {
+ *fully_qualified_name = namesuff + 1;
+ return DNS_SUCCEED;
+ }
+ }
+ }
+ return DNS_NOMATCH;
+ }
+
/* Control should never reach here */
return DNS_FAIL;
-/* $Cambridge: exim/src/src/exim.h,v 1.11 2005/04/27 10:00:18 ph10 Exp $ */
+/* $Cambridge: exim/src/src/exim.h,v 1.12 2005/05/10 10:19:11 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
#define T_SRV 33
#endif
-/* We use the private type T_ZNS for retrieving the nameservers for the
-enclosing zone of a domain, and the private type T_MXH for retrieving
-the MX hostnames only (without their priorities). */
+/* We define a few private types for special DNS lookups:
+
+ . T_ZNS gets the nameservers of the enclosing zone of a domain
+
+ . T_MXH gets the MX hostnames only (without their priorities)
+
+ . T_CSA gets the domain's Client SMTP Authorization SRV record
+
+*/
#define T_ZNS (-1)
#define T_MXH (-2)
+#define T_CSA (-3)
/* The resolv.h header defines __P(x) on some Solaris 2.5.1 systems (without
checking that it is already defined, in fact). This conflicts with other
-/* $Cambridge: exim/src/src/expand.c,v 1.20 2005/04/28 13:29:27 ph10 Exp $ */
+/* $Cambridge: exim/src/src/expand.c,v 1.21 2005/05/10 10:19:11 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
{ "caller_uid", vtype_uid, &real_uid },
{ "compile_date", vtype_stringptr, &version_date },
{ "compile_number", vtype_stringptr, &version_cnumber },
+ { "csa_status", vtype_stringptr, &csa_status },
#ifdef WITH_OLD_DEMIME
{ "demime_errorlevel", vtype_int, &demime_errorlevel },
{ "demime_reason", vtype_stringptr, &demime_reason },
-/* $Cambridge: exim/src/src/globals.c,v 1.23 2005/05/03 14:20:01 ph10 Exp $ */
+/* $Cambridge: exim/src/src/globals.c,v 1.24 2005/05/10 10:19:11 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
int continue_sequence = 1;
uschar *continue_transport = NULL;
+uschar *csa_status = NULL;
+
BOOL daemon_listen = FALSE;
uschar *daemon_smtp_port = US"smtp";
BOOL debug_daemon = FALSE;
#endif
uschar *dns_again_means_nonexist = NULL;
+int dns_csa_search_limit = 5;
+BOOL dns_csa_use_reverse = TRUE;
uschar *dns_ipv4_lookup = NULL;
int dns_retrans = 0;
int dns_retry = 0;
-/* $Cambridge: exim/src/src/globals.h,v 1.15 2005/05/03 14:20:01 ph10 Exp $ */
+/* $Cambridge: exim/src/src/globals.h,v 1.16 2005/05/10 10:19:11 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
extern int continue_sequence; /* Sequence num for continued delivery */
extern uschar *continue_transport; /* Transport for continued delivery */
+extern uschar *csa_status; /* Client SMTP Authorization result */
+
extern BOOL daemon_listen; /* True if listening required */
extern uschar *daemon_smtp_port; /* Can be a list of ports */
extern BOOL debug_daemon; /* Debug the daemon process only */
#endif
extern uschar *dns_again_means_nonexist; /* Domains that are badly set up */
+extern int dns_csa_search_limit; /* How deep to search for CSA SRV records */
+extern BOOL dns_csa_use_reverse; /* Check CSA in reverse DNS? (non-standard) */
extern uschar *dns_ipv4_lookup; /* For these domains, don't look for AAAA (or A6) */
extern int dns_retrans; /* Retransmission time setting */
extern int dns_retry; /* Number of retries */
-/* $Cambridge: exim/src/src/lookups/dnsdb.c,v 1.10 2005/02/17 11:58:27 ph10 Exp $ */
+/* $Cambridge: exim/src/src/lookups/dnsdb.c,v 1.11 2005/05/10 10:19:11 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
#endif
#endif
"cname",
+ "csa",
"mx",
"mxh",
"ns",
#endif
#endif
T_CNAME,
+ T_CSA, /* Private type for "Client SMTP Authorization". */
T_MX,
T_MXH, /* Private type for "MX hostnames" */
T_NS,
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
!= 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 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). This
- code for doing the reversal is now in a separate function. */
-
- if (type == T_PTR && string_is_ip_address(domain, NULL) > 0)
+ 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;
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)
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));
-/* $Cambridge: exim/src/src/macros.h,v 1.12 2005/04/07 10:54:54 ph10 Exp $ */
+/* $Cambridge: exim/src/src/macros.h,v 1.13 2005/05/10 10:19:11 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
/* Options for dns_next_rr */
-enum { RESET_NEXT, RESET_ANSWERS, RESET_ADDITIONAL };
+enum { RESET_NEXT, RESET_ANSWERS, RESET_AUTHORITY, RESET_ADDITIONAL };
/* Argument values for the time-of-day function */
-/* $Cambridge: exim/src/src/readconf.c,v 1.7 2005/04/05 13:58:35 ph10 Exp $ */
+/* $Cambridge: exim/src/src/readconf.c,v 1.8 2005/05/10 10:19:11 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
{ "delivery_date_remove", opt_bool, &delivery_date_remove },
{ "dns_again_means_nonexist", opt_stringptr, &dns_again_means_nonexist },
{ "dns_check_names_pattern", opt_stringptr, &check_dns_names_pattern },
+ { "dns_csa_search_limit", opt_int, &dns_csa_search_limit },
+ { "dns_csa_use_reverse", opt_bool, &dns_csa_use_reverse },
{ "dns_ipv4_lookup", opt_stringptr, &dns_ipv4_lookup },
{ "dns_retrans", opt_time, &dns_retrans },
{ "dns_retry", opt_int, &dns_retry },
-/* $Cambridge: exim/src/src/version.c,v 1.7 2005/03/01 10:21:44 ph10 Exp $ */
+/* $Cambridge: exim/src/src/version.c,v 1.8 2005/05/10 10:19:11 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
#include "exim.h"
-#define THIS_VERSION "4.51"
+#define THIS_VERSION "4.52"
/* The header file cnumber.h contains a single line containing the
git://git.exim.org / exim.git / commitdiff