-/* $Cambridge: exim/src/src/host.c,v 1.16 2005/10/03 09:51:04 ph10 Exp $ */
-
/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2005 */
+/* Copyright (c) University of Cambridge 1995 - 2012 */
/* See the file NOTICE for conditions of use and distribution. */
/* Functions for finding hosts, either by gethostbyname(), gethostbyaddr(), or
very good for the uses to which it is put. When running the regression tests,
start with a fixed seed.
+If you need better, see vaguely_random_number() which is potentially stronger,
+if a crypto library is available, but might end up just calling this instead.
+
Arguments:
limit: one more than the largest number required
int
random_number(int limit)
{
+if (limit < 1)
+ return 0;
if (random_seed == 0)
{
if (running_in_test_harness) random_seed = 42; else
-/*************************************************
-* Sort addresses when testing *
-*************************************************/
-
-/* This function is called only when running in the test harness. It sorts a
-number of multihomed host IP addresses into the order, so as to get
-repeatability. This doesn't have to be efficient. But don't interchange IPv4
-and IPv6 addresses!
-
-NOTE:
-This sorting is not necessary for the new test harness, because it
-doesn't call the real DNS resolver, and its output is repeatable. However,
-until the old test harness is discarded, we need to retain this capability.
-The new harness is being developed towards the end of 2005. It will be some
-time before it can do everything that the old one can do.
-
-Arguments:
- host -> the first host item
- last -> the last host item
-
-Returns: nothing
-*/
-
-static void
-sort_addresses(host_item *host, host_item *last)
-{
-BOOL done = FALSE;
-while (!done)
- {
- host_item *h;
- done = TRUE;
- for (h = host; h != last; h = h->next)
- {
- if ((Ustrchr(h->address, ':') == NULL) !=
- (Ustrchr(h->next->address, ':') == NULL))
- continue;
- if (Ustrcmp(h->address, h->next->address) > 0)
- {
- uschar *temp = h->address;
- h->address = h->next->address;
- h->next->address = temp;
- done = FALSE;
- }
- }
- }
-}
-
-
-
/*************************************************
* Replace gethostbyname() when testing *
*************************************************/
"manyhome.test.ex" and generates a humungous number of IP addresses. It also
recognizes an unqualified "localhost" and forces it to the appropriate loopback
address. IP addresses are treated as literals. For other names, it uses the DNS
-to find the host name. In the new test harness, this means it will access only
-the fake DNS resolver. In the old harness it will call the real resolver and
-access the test zone.
+to find the host name. In the test harness, this means it will access only the
+fake DNS resolver.
Arguments:
name the host name or a textual IP address
int rc = dns_lookup(&dnsa, lname, type, NULL);
int count = 0;
+ lookup_dnssec_authenticated = NULL;
+
switch(rc)
{
case DNS_SUCCEED: break;
(a) No sender_host_name or sender_helo_name: "[ip address]"
(b) Just sender_host_name: "host_name [ip address]"
-(c) Just sender_helo_name: "(helo_name) [ip address]"
-(d) The two are identical: "host_name [ip address]"
+(c) Just sender_helo_name: "(helo_name) [ip address]" unless helo is IP
+ in which case: "[ip address}"
+(d) The two are identical: "host_name [ip address]" includes helo = IP
(e) The two are different: "host_name (helo_name) [ip address]"
If log_incoming_port is set, the sending host's port number is added to the IP
void
host_build_sender_fullhost(void)
{
+BOOL show_helo = TRUE;
uschar *address;
+int len;
int old_pool = store_pool;
if (sender_host_address == NULL) return;
if ((log_extra_selector & LX_incoming_port) == 0 || sender_host_port <= 0)
*(Ustrrchr(address, ':')) = 0;
+/* If there's no EHLO/HELO data, we can't show it. */
+
+if (sender_helo_name == NULL) show_helo = FALSE;
+
+/* If HELO/EHLO was followed by an IP literal, it's messy because of two
+features of IPv6. Firstly, there's the "IPv6:" prefix (Exim is liberal and
+doesn't require this, for historical reasons). Secondly, IPv6 addresses may not
+be given in canonical form, so we have to canonicize them before comparing. As
+it happens, the code works for both IPv4 and IPv6. */
+
+else if (sender_helo_name[0] == '[' &&
+ sender_helo_name[(len=Ustrlen(sender_helo_name))-1] == ']')
+ {
+ int offset = 1;
+ uschar *helo_ip;
+
+ if (strncmpic(sender_helo_name + 1, US"IPv6:", 5) == 0) offset += 5;
+ if (strncmpic(sender_helo_name + 1, US"IPv4:", 5) == 0) offset += 5;
+
+ helo_ip = string_copyn(sender_helo_name + offset, len - offset - 1);
+
+ if (string_is_ip_address(helo_ip, NULL) != 0)
+ {
+ int x[4], y[4];
+ int sizex, sizey;
+ uschar ipx[48], ipy[48]; /* large enough for full IPv6 */
+
+ sizex = host_aton(helo_ip, x);
+ sizey = host_aton(sender_host_address, y);
+
+ (void)host_nmtoa(sizex, x, -1, ipx, ':');
+ (void)host_nmtoa(sizey, y, -1, ipy, ':');
+
+ if (strcmpic(ipx, ipy) == 0) show_helo = FALSE;
+ }
+ }
+
/* Host name is not verified */
if (sender_host_name == NULL)
sender_rcvhost = string_cat(NULL, &size, &ptr, address, adlen);
- if (sender_ident != NULL || sender_helo_name != NULL || portptr != NULL)
+ if (sender_ident != NULL || show_helo || portptr != NULL)
{
int firstptr;
sender_rcvhost = string_cat(sender_rcvhost, &size, &ptr, US" (", 2);
sender_rcvhost = string_append(sender_rcvhost, &size, &ptr, 2, US"port=",
portptr + 1);
- if (sender_helo_name != NULL)
+ if (show_helo)
sender_rcvhost = string_append(sender_rcvhost, &size, &ptr, 2,
(firstptr == ptr)? US"helo=" : US" helo=", sender_helo_name);
store_reset(sender_rcvhost + ptr + 1);
}
-/* Host name is known and verified. */
+/* Host name is known and verified. Unless we've already found that the HELO
+data matches the IP address, compare it with the name. */
else
{
- int len;
- BOOL no_helo = FALSE;
-
- /* Comparing a HELO name to a host name is easy */
-
- if (sender_helo_name == NULL ||
- strcmpic(sender_host_name, sender_helo_name) == 0)
- no_helo = TRUE;
-
- /* If HELO/EHLO was followed by an IP literal, it's much more messy because
- of two features of IPv6. Firstly, there's the "IPv6:" prefix (Exim is liberal
- and doesn't require this, for historical reasons). Secondly, an IPv6 address
- may not be given in canonical form, so we have to canonicize it before
- comparing. As it happens, the code works for both IPv4 and IPv6. */
-
- else if (sender_helo_name[0] == '[' &&
- sender_helo_name[(len=Ustrlen(sender_helo_name))-1] == ']')
- {
- uschar *helo_ip;
- int offset = 1;
-
- if (strncmpic(sender_helo_name+1, US"IPv6:",5) == 0) offset += 5;
- helo_ip = string_copyn(sender_helo_name + offset, len - offset - 1);
-
- if (string_is_ip_address(helo_ip, NULL) != 0)
- {
- int x[4];
- int size;
- size = host_aton(helo_ip, x);
- helo_ip = store_get(48); /* large enough for full IPv6 */
- (void)host_nmtoa(size, x, -1, helo_ip, ':');
- if (strcmpic(helo_ip, sender_host_address) == 0) no_helo = TRUE;
- }
- }
+ if (show_helo && strcmpic(sender_host_name, sender_helo_name) == 0)
+ show_helo = FALSE;
- if (no_helo)
- {
- sender_fullhost = string_sprintf("%s %s", sender_host_name, address);
- sender_rcvhost = (sender_ident == NULL)?
- string_sprintf("%s (%s)", sender_host_name, address) :
- string_sprintf("%s (%s ident=%s)", sender_host_name, address,
- sender_ident);
- }
- else
+ if (show_helo)
{
sender_fullhost = string_sprintf("%s (%s) %s", sender_host_name,
sender_helo_name, address);
string_sprintf("%s\n\t(%s helo=%s ident=%s)", sender_host_name,
address, sender_helo_name, sender_ident);
}
+ else
+ {
+ sender_fullhost = string_sprintf("%s %s", sender_host_name, address);
+ sender_rcvhost = (sender_ident == NULL)?
+ string_sprintf("%s (%s)", sender_host_name, address) :
+ string_sprintf("%s (%s ident=%s)", sender_host_name, address,
+ sender_ident);
+ }
}
store_pool = old_pool;
while ((s = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
{
+ int ipv;
int port = host_address_extract_port(s); /* Leaves just the IP address */
- if (string_is_ip_address(s, NULL) == 0)
+ if ((ipv = string_is_ip_address(s, NULL)) == 0)
log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Malformed IP address \"%s\" in %s",
s, name);
+ /* Skip IPv6 addresses if IPv6 is disabled. */
+
+ if (disable_ipv6 && ipv == 6) continue;
+
/* This use of strcpy() is OK because we have checked that s is a valid IP
address above. The field in the ip_address_item is large enough to hold an
IPv6 address. */
{
int sep = 0;
uschar buffer[32];
-uschar *list = tls_on_connect_ports;
+uschar *list = tls_in.on_connect_ports;
uschar *s;
+uschar *end;
-if (tls_on_connect) return TRUE;
+if (tls_in.on_connect) return TRUE;
-while ((s = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
- {
- uschar *end;
- int lport = Ustrtol(s, &end, 10);
- if (*end != 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "tls_on_connect_ports "
- "contains \"%s\", which is not a port number: exim abandoned", s);
- if (lport == port) return TRUE;
- }
+while ((s = string_nextinlist(&list, &sep, buffer, sizeof(buffer))))
+ if (Ustrtol(s, &end, 10) == port)
+ return TRUE;
return FALSE;
}
treat this as non-existent. In some operating systems, this is returned as an
empty string; in others as a single dot. */
-if (hosts->h_name[0] == 0 || hosts->h_name[0] == '.')
+if (hosts->h_name == NULL || hosts->h_name[0] == 0 || hosts->h_name[0] == '.')
{
HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an empty name: "
"treated as non-existent host name\n");
dns_answer dnsa;
dns_scan dnss;
-host_lookup_deferred = host_lookup_failed = FALSE;
+sender_host_dnssec = host_lookup_deferred = host_lookup_failed = FALSE;
HDEBUG(D_host_lookup)
debug_printf("looking up host name for %s\n", sender_host_address);
{
if (strcmpic(ordername, US"bydns") == 0)
{
- dns_init(FALSE, FALSE);
+ dns_init(FALSE, FALSE, FALSE); /* dnssec ctrl by dns_dnssec_ok glbl */
dns_build_reverse(sender_host_address, buffer);
rc = dns_lookup(&dnsa, buffer, T_PTR, NULL);
int count = 0;
int old_pool = store_pool;
+ /* Ideally we'd check DNSSEC both forward and reverse, but we use the
+ gethost* routines for forward, so can't do that unless/until we rewrite. */
+ sender_host_dnssec = dns_is_secure(&dnsa);
+ DEBUG(D_dns)
+ debug_printf("Reverse DNS security status: %s\n",
+ sender_host_dnssec ? "DNSSEC verified (AD)" : "unverified");
+
store_pool = POOL_PERM; /* Save names in permanent storage */
for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
return FAIL;
}
-/* We have a host name. If we are running in the test harness, we want the host
-name and its alias to appear always the same way round. There are only ever two
-names in these tests. If one of them contains "alias", make sure it is second;
-otherwise put them in alphabetical order. */
-
-if (running_in_test_harness && *sender_host_aliases != NULL &&
- (
- Ustrstr(sender_host_name, "alias") != NULL ||
- (
- Ustrstr(*sender_host_aliases, "alias") == NULL &&
- Ustrcmp(sender_host_name, *sender_host_aliases) > 0
- )
- ))
- {
- uschar *temp = sender_host_name;
- sender_host_name = *sender_host_aliases;
- *sender_host_aliases = temp;
- }
-
-/* Debug output what was found, after test harness swapping, for consistency */
-
HDEBUG(D_host_lookup)
{
uschar **aliases = sender_host_aliases;
h.mx = MX_NONE;
h.address = NULL;
- /* When called with the 5th argument FALSE, host_find_byname() won't return
+ /* When called with the last argument FALSE, host_find_byname() won't return
HOST_FOUND_LOCAL. If the incoming address is an IPv4 address expressed in
IPv6 format, we must compare the IPv4 part to any IPv4 addresses. */
- if ((rc = host_find_byname(&h, NULL, NULL, FALSE)) == HOST_FOUND)
+ if ((rc = host_find_byname(&h, NULL, 0, NULL, FALSE)) == HOST_FOUND)
{
host_item *hh;
- uschar *address_ipv4 = (Ustrncmp(sender_host_address, "::ffff:", 7) == 0)?
- sender_host_address + 7 : sender_host_address;
HDEBUG(D_host_lookup) debug_printf("checking addresses for %s\n", hname);
for (hh = &h; hh != NULL; hh = hh->next)
{
- if ((Ustrcmp(hh->address, (Ustrchr(hh->address, ':') == NULL)?
- address_ipv4 : sender_host_address)) == 0)
+ if (host_is_in_net(hh->address, sender_host_address, 0))
{
HDEBUG(D_host_lookup) debug_printf(" %s OK\n", hh->address);
ok = TRUE;
{
HDEBUG(D_host_lookup) debug_printf("temporary error for host name lookup\n");
host_lookup_deferred = TRUE;
+ sender_host_name = NULL;
return DEFER;
}
else
*************************************************/
/* The input is a host_item structure with the name filled in and the address
-field set to NULL. We use gethostbyname(). Of course, gethostbyname() may use
-the DNS, but it doesn't do MX processing. If more than one address is given,
-chain on additional host items, with other relevant fields copied.
+field set to NULL. We use gethostbyname() or getipnodebyname() or
+gethostbyname2(), as appropriate. Of course, these functions may use the DNS,
+but they do not do MX processing. It appears, however, that in some systems the
+current setting of resolver options is used when one of these functions calls
+the resolver. For this reason, we call dns_init() at the start, with arguments
+influenced by bits in "flags", just as we do for host_find_bydns().
The second argument provides a host list (usually an IP list) of hosts to
ignore. This makes it possible to ignore IPv6 link-local addresses or loopback
multiple IP addresses cause other host items to be
chained on.
ignore_target_hosts a list of hosts to ignore
+ flags HOST_FIND_QUALIFY_SINGLE ) passed to
+ HOST_FIND_SEARCH_PARENTS ) dns_init()
fully_qualified_name if not NULL, set to point to host name for
compatibility with host_find_bydns
local_host_check TRUE if a check for the local host is wanted
*/
int
-host_find_byname(host_item *host, uschar *ignore_target_hosts,
+host_find_byname(host_item *host, uschar *ignore_target_hosts, int flags,
uschar **fully_qualified_name, BOOL local_host_check)
{
int i, yield, times;
#endif
/* If we are in the test harness, a name ending in .test.again.dns always
-forces a temporary error response. */
+forces a temporary error response, unless the name is in
+dns_again_means_nonexist. */
if (running_in_test_harness)
{
uschar *endname = host->name + Ustrlen(host->name);
- if (Ustrcmp(endname - 14, "test.again.dns") == 0)
- return HOST_FIND_AGAIN;
+ if (Ustrcmp(endname - 14, "test.again.dns") == 0) goto RETURN_AGAIN;
}
-/* In an IPv6 world, we need to scan for both kinds of address, so go round the
-loop twice. Note that we have ensured that AF_INET6 is defined even in an IPv4
-world, which makes for slightly tidier code. However, if dns_ipv4_lookup
-matches the domain, we also just do IPv4 lookups here (except when testing
-standalone). */
+/* Make sure DNS options are set as required. This appears to be necessary in
+some circumstances when the get..byname() function actually calls the DNS. */
+
+dns_init((flags & HOST_FIND_QUALIFY_SINGLE) != 0,
+ (flags & HOST_FIND_SEARCH_PARENTS) != 0,
+ FALSE); /*XXX dnssec? */
+
+/* In an IPv6 world, unless IPv6 has been disabled, we need to scan for both
+kinds of address, so go round the loop twice. Note that we have ensured that
+AF_INET6 is defined even in an IPv4 world, which makes for slightly tidier
+code. However, if dns_ipv4_lookup matches the domain, we also just do IPv4
+lookups here (except when testing standalone). */
#if HAVE_IPV6
- #ifndef STAND_ALONE
- if (dns_ipv4_lookup != NULL &&
+ #ifdef STAND_ALONE
+ if (disable_ipv6)
+ #else
+ if (disable_ipv6 ||
+ (dns_ipv4_lookup != NULL &&
match_isinlist(host->name, &dns_ipv4_lookup, 0, NULL, NULL, MCL_DOMAIN,
- TRUE, NULL) == OK)
+ TRUE, NULL) == OK))
+ #endif
+
{ af = AF_INET; times = 1; }
else
- #endif /* STAND_ALONE */
-
{ af = AF_INET6; times = 2; }
/* No IPv6 support */
i++)
{
BOOL ipv4_addr;
- int error_num;
+ int error_num = 0;
struct hostent *hostdata;
+ #ifdef STAND_ALONE
+ printf("Looking up: %s\n", host->name);
+ #endif
+
#if HAVE_IPV6
if (running_in_test_harness)
hostdata = host_fake_gethostbyname(host->name, af, &error_num);
host->port = PORT_NONE;
host->status = hstatus_unknown;
host->why = hwhy_unknown;
+ host->dnssec = DS_UNK;
last = host;
}
next->port = PORT_NONE;
next->status = hstatus_unknown;
next->why = hwhy_unknown;
+ next->dnssec = DS_UNK;
next->last_try = 0;
next->next = last->next;
last->next = next;
string_sprintf("no IP address found for host %s", host->name);
HDEBUG(D_host_lookup) debug_printf("%s\n", msg);
- if (temp_error) return HOST_FIND_AGAIN;
+ if (temp_error) goto RETURN_AGAIN;
if (host_checking || !log_testing_mode)
log_write(L_host_lookup_failed, LOG_MAIN, "%s", msg);
return HOST_FIND_FAILED;
yield = local_host_check?
host_scan_for_local_hosts(host, &last, NULL) : HOST_FOUND;
-/* When running in the test harness, sort into the order of addresses so as to
-get repeatability. */
-
-if (running_in_test_harness) sort_addresses(host, last);
-
HDEBUG(D_host_lookup)
{
host_item *h;
/* Return the found status. */
return yield;
+
+/* Handle the case when there is a temporary error. If the name matches
+dns_again_means_nonexist, return permanent rather than temporary failure. */
+
+RETURN_AGAIN:
+ {
+ #ifndef STAND_ALONE
+ int rc;
+ uschar *save = deliver_domain;
+ deliver_domain = host->name; /* set $domain */
+ rc = match_isinlist(host->name, &dns_again_means_nonexist, 0, NULL, NULL,
+ MCL_DOMAIN, TRUE, NULL);
+ deliver_domain = save;
+ if (rc == OK)
+ {
+ DEBUG(D_host_lookup) debug_printf("%s is in dns_again_means_nonexist: "
+ "returning HOST_FIND_FAILED\n", host->name);
+ return HOST_FIND_FAILED;
+ }
+ #endif
+ return HOST_FIND_AGAIN;
+ }
}
* Fill in a host address from the DNS *
*************************************************/
-/* Given a host item, with its name and mx fields set, and its address field
-set to NULL, fill in its IP address from the DNS. If it is multi-homed, create
-additional host items for the additional addresses, copying all the other
-fields, and randomizing the order.
+/* Given a host item, with its name, port and mx fields set, and its address
+field set to NULL, fill in its IP address from the DNS. If it is multi-homed,
+create additional host items for the additional addresses, copying all the
+other fields, and randomizing the order.
On IPv6 systems, A6 records are sought first (but only if support for A6 is
configured - they may never become mainstream), then AAAA records are sought,
fully_qualified_name if not NULL, return fully qualified name here if
the contents are different (i.e. it must be preset
to something)
+ dnnssec_require if TRUE check the DNS result AD bit
Returns: HOST_FIND_FAILED couldn't find A record
HOST_FIND_AGAIN try again later
static int
set_address_from_dns(host_item *host, host_item **lastptr,
- uschar *ignore_target_hosts, BOOL allow_ip, uschar **fully_qualified_name)
+ uschar *ignore_target_hosts, BOOL allow_ip, uschar **fully_qualified_name,
+ BOOL dnssec_request, BOOL dnssec_require)
{
dns_record *rr;
host_item *thishostlast = NULL; /* Indicates not yet filled in anything */
#endif
host->address = host->name;
- host->port = PORT_NONE;
return HOST_FOUND;
}
-/* On an IPv6 system, go round the loop up to three times, looking for A6 and
-AAAA records the first two times. However, unless doing standalone testing, we
-force an IPv4 lookup if the domain matches dns_ipv4_lookup is set. Since A6
-records look like being abandoned, support them only if explicitly configured
-to do so. On an IPv4 system, go round the loop once only, looking only for A
-records. */
+/* On an IPv6 system, unless IPv6 is disabled, go round the loop up to three
+times, looking for A6 and AAAA records the first two times. However, unless
+doing standalone testing, we force an IPv4 lookup if the domain matches
+dns_ipv4_lookup is set. Since A6 records look like being abandoned, support
+them only if explicitly configured to do so. On an IPv4 system, go round the
+loop once only, looking only for A records. */
#if HAVE_IPV6
#ifndef STAND_ALONE
- if (dns_ipv4_lookup != NULL &&
+ if (disable_ipv6 || (dns_ipv4_lookup != NULL &&
match_isinlist(host->name, &dns_ipv4_lookup, 0, NULL, NULL, MCL_DOMAIN,
- TRUE, NULL) == OK)
+ TRUE, NULL) == OK))
i = 0; /* look up A records only */
else
#endif /* STAND_ALONE */
dns_scan dnss;
int rc = dns_lookup(&dnsa, host->name, type, fully_qualified_name);
+ lookup_dnssec_authenticated = !dnssec_request ? NULL
+ : dns_is_secure(&dnsa) ? US"yes" : US"no";
/* We want to return HOST_FIND_AGAIN if one of the A, A6, or AAAA lookups
fails or times out, but not if another one succeeds. (In the early
continue;
}
+ if (dnssec_request)
+ {
+ if (dns_is_secure(&dnsa))
+ {
+ DEBUG(D_host_lookup) debug_printf("%s A DNSSEC\n", host->name);
+ if (host->dnssec == DS_UNK) /* set in host_find_bydns() */
+ host->dnssec = DS_YES;
+ }
+ else
+ {
+ if (dnssec_require)
+ {
+ log_write(L_host_lookup_failed, LOG_MAIN,
+ "dnssec fail on %s for %.256s",
+ i>1 ? "A6" : i>0 ? "AAAA" : "A", host->name);
+ continue;
+ }
+ if (host->dnssec == DS_YES) /* set in host_find_bydns() */
+ {
+ DEBUG(D_host_lookup) debug_printf("%s A cancel DNSSEC\n", host->name);
+ host->dnssec = DS_NO;
+ lookup_dnssec_authenticated = US"no";
+ }
+ }
+ }
+
/* Lookup succeeded: fill in the given host item with the first non-ignored
address found; create additional items for any others. A single A6 record
may generate more than one address. */
if (strcmpic(host->name, rr->name) != 0)
host->name = string_copy_dnsdomain(rr->name);
host->address = da->address;
- host->port = PORT_NONE;
host->sort_key = host->mx * 1000 + random_number(500) + randoffset;
host->status = hstatus_unknown;
host->why = hwhy_unknown;
if (new_sort_key < host->sort_key)
{
- *next = *host;
+ *next = *host; /* Copies port */
host->next = next;
host->address = da->address;
- host->port = PORT_NONE;
host->sort_key = new_sort_key;
if (thishostlast == host) thishostlast = next; /* Local last */
if (*lastptr == host) *lastptr = next; /* Global last */
if (new_sort_key < h->next->sort_key) break;
h = h->next;
}
- *next = *h;
+ *next = *h; /* Copies port */
h->next = next;
next->address = da->address;
- next->port = PORT_NONE;
next->sort_key = new_sort_key;
if (h == thishostlast) thishostlast = next; /* Local last */
if (h == *lastptr) *lastptr = next; /* Global last */
/*************************************************
-* Find IP addresses and names for host via DNS *
+* Find IP addresses and host names via DNS *
*************************************************/
-/* The input is a host_item structure with the name filled in and the address
-field set to NULL. This may be in a chain of other host items. The lookup may
-result in more than one IP address, in which case we must created new host
-blocks for the additional addresses, and insert them into the chain. The
-original name may not be fully qualified. Use the fully_qualified_name argument
-to return the official name, as returned by the resolver.
+/* The input is a host_item structure with the name field filled in and the
+address field set to NULL. This may be in a chain of other host items. The
+lookup may result in more than one IP address, in which case we must created
+new host blocks for the additional addresses, and insert them into the chain.
+The original name may not be fully qualified. Use the fully_qualified_name
+argument to return the official name, as returned by the resolver.
Arguments:
host point to initial host item
srv_service when SRV used, the service name
srv_fail_domains DNS errors for these domains => assume nonexist
mx_fail_domains DNS errors for these domains => assume nonexist
+ dnssec_request_domains => make dnssec request
+ dnssec_require_domains => ditto and nonexist failures
fully_qualified_name if not NULL, return fully-qualified name
removed set TRUE if local host was removed from the list
int
host_find_bydns(host_item *host, uschar *ignore_target_hosts, int whichrrs,
uschar *srv_service, uschar *srv_fail_domains, uschar *mx_fail_domains,
+ uschar *dnssec_request_domains, uschar *dnssec_require_domains,
uschar **fully_qualified_name, BOOL *removed)
{
host_item *h, *last;
int yield;
dns_answer dnsa;
dns_scan dnss;
+BOOL dnssec_require = match_isinlist(host->name, &dnssec_require_domains,
+ 0, NULL, NULL, MCL_DOMAIN, TRUE, NULL) == OK;
+BOOL dnssec_request = dnssec_require
+ || match_isinlist(host->name, &dnssec_request_domains,
+ 0, NULL, NULL, MCL_DOMAIN, TRUE, NULL) == OK;
+dnssec_status_t dnssec;
/* Set the default fully qualified name to the incoming name, initialize the
resolver if necessary, set up the relevant options, and initialize the flag
if (fully_qualified_name != NULL) *fully_qualified_name = host->name;
dns_init((whichrrs & HOST_FIND_QUALIFY_SINGLE) != 0,
- (whichrrs & HOST_FIND_SEARCH_PARENTS) != 0);
+ (whichrrs & HOST_FIND_SEARCH_PARENTS) != 0,
+ dnssec_request
+ );
host_find_failed_syntax = FALSE;
/* First, if requested, look for SRV records. The service name is given; we
the input name, pass back the new original domain, without the prepended
magic. */
+ dnssec = DS_UNK;
+ lookup_dnssec_authenticated = NULL;
rc = dns_lookup(&dnsa, buffer, ind_type, &temp_fully_qualified_name);
+
+ if (dnssec_request)
+ {
+ if (dns_is_secure(&dnsa))
+ { dnssec = DS_YES; lookup_dnssec_authenticated = US"yes"; }
+ else
+ { dnssec = DS_NO; lookup_dnssec_authenticated = US"no"; }
+ }
+
if (temp_fully_qualified_name != buffer && fully_qualified_name != NULL)
*fully_qualified_name = temp_fully_qualified_name + prefix_length;
/* On DNS failures, we give the "try again" error unless the domain is
listed as one for which we continue. */
+ if (rc == DNS_SUCCEED && dnssec_require && !dns_is_secure(&dnsa))
+ {
+ log_write(L_host_lookup_failed, LOG_MAIN,
+ "dnssec fail on SRV for %.256s", host->name);
+ rc = DNS_FAIL;
+ }
if (rc == DNS_FAIL || rc == DNS_AGAIN)
{
#ifndef STAND_ALONE
if (match_isinlist(host->name, &srv_fail_domains, 0, NULL, NULL, MCL_DOMAIN,
TRUE, NULL) != OK)
#endif
- return HOST_FIND_AGAIN;
+ { yield = HOST_FIND_AGAIN; goto out; }
DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
"(domain in srv_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
}
if (rc != DNS_SUCCEED && (whichrrs & HOST_FIND_BY_MX) != 0)
{
ind_type = T_MX;
+ dnssec = DS_UNK;
+ lookup_dnssec_authenticated = NULL;
rc = dns_lookup(&dnsa, host->name, ind_type, fully_qualified_name);
- if (rc == DNS_NOMATCH) return HOST_FIND_FAILED;
- if (rc == DNS_FAIL || rc == DNS_AGAIN)
+
+ if (dnssec_request)
{
- #ifndef STAND_ALONE
- if (match_isinlist(host->name, &mx_fail_domains, 0, NULL, NULL, MCL_DOMAIN,
- TRUE, NULL) != OK)
- #endif
- return HOST_FIND_AGAIN;
- DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
- "(domain in mx_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
+ if (dns_is_secure(&dnsa))
+ {
+ DEBUG(D_host_lookup) debug_printf("%s MX DNSSEC\n", host->name);
+ dnssec = DS_YES; lookup_dnssec_authenticated = US"yes";
+ }
+ else
+ {
+ dnssec = DS_NO; lookup_dnssec_authenticated = US"no";
+ }
+ }
+
+ switch (rc)
+ {
+ case DNS_NOMATCH:
+ yield = HOST_FIND_FAILED; goto out;
+
+ case DNS_SUCCEED:
+ if (!dnssec_require || dns_is_secure(&dnsa))
+ break;
+ log_write(L_host_lookup_failed, LOG_MAIN,
+ "dnssec fail on MX for %.256s", host->name);
+ rc = DNS_FAIL;
+ /*FALLTHROUGH*/
+
+ case DNS_FAIL:
+ case DNS_AGAIN:
+ #ifndef STAND_ALONE
+ if (match_isinlist(host->name, &mx_fail_domains, 0, NULL, NULL, MCL_DOMAIN,
+ TRUE, NULL) != OK)
+ #endif
+ { yield = HOST_FIND_AGAIN; goto out; }
+ DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
+ "(domain in mx_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
+ break;
}
}
if ((whichrrs & HOST_FIND_BY_A) == 0)
{
DEBUG(D_host_lookup) debug_printf("Address records are not being sought\n");
- return HOST_FIND_FAILED;
+ yield = HOST_FIND_FAILED;
+ goto out;
}
last = host; /* End of local chainlet */
host->mx = MX_NONE;
host->port = PORT_NONE;
+ host->dnssec = DS_UNK;
+ lookup_dnssec_authenticated = NULL;
rc = set_address_from_dns(host, &last, ignore_target_hosts, FALSE,
- fully_qualified_name);
+ fully_qualified_name, dnssec_request, dnssec_require);
/* If one or more address records have been found, check that none of them
are local. Since we know the host items all have their IP addresses
else
if (rc == HOST_IGNORED) rc = HOST_FIND_FAILED; /* No special action */
- /* When running in the test harness, sort into the order of addresses so as
- to get repeatability. */
-
- if (running_in_test_harness) sort_addresses(host, last);
-
DEBUG(D_host_lookup)
{
host_item *h;
}
}
- return rc;
+ yield = rc;
+ goto out;
}
/* We have found one or more MX or SRV records. Sort them according to
{
int precedence;
int weight = 0; /* For SRV records */
- int port = PORT_NONE; /* For SRV records */
+ int port = PORT_NONE;
uschar *s; /* MUST be unsigned for GETSHORT */
uschar data[256];
the same precedence to sort randomly. */
if (ind_type == T_MX)
- {
weight = random_number(500);
- }
/* SRV records are specified with a port and a weight. The weight is used
in a special algorithm. However, to start with, we just use it to order the
host->sort_key = precedence * 1000 + weight;
host->status = hstatus_unknown;
host->why = hwhy_unknown;
+ host->dnssec = dnssec;
last = host;
}
next->sort_key = sort_key;
next->status = hstatus_unknown;
next->why = hwhy_unknown;
+ next->dnssec = dnssec;
next->last_try = 0;
/* Handle the case when we have to insert before the first item. */
if (host == last && host->name[0] == 0)
{
DEBUG(D_host_lookup) debug_printf("the single SRV record is \".\"\n");
- return HOST_FIND_FAILED;
+ yield = HOST_FIND_FAILED;
+ goto out;
}
DEBUG(D_host_lookup)
} /* Move on to the next host */
}
-/* Now we have to ensure addresses exist for all the hosts. We have ensured
-above that the names in the host items are all unique. The addresses may have
-been returned in the additional data section of the DNS query. Because it is
-more expensive to scan the returned DNS records (because you have to expand the
-names) we do a single scan over them, and multiple scans of the chain of host
-items (which is typically only 3 or 4 long anyway.) Add extra host items for
-multi-homed hosts. */
-
-for (rr = dns_next_rr(&dnsa, &dnss, RESET_ADDITIONAL);
- rr != NULL;
- rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
- {
- dns_address *da;
- int status = hstatus_unknown;
- int why = hwhy_unknown;
- int randoffset;
-
- if (rr->type != T_A
- #if HAVE_IPV6
- && rr->type != T_AAAA
- #ifdef SUPPORT_A6
- && rr->type != T_A6
- #endif
- #endif
- ) continue;
-
- /* Find the first host that matches this record's name. If there isn't
- one, move on to the next RR. */
-
- for (h = host; h != last->next; h = h->next)
- { if (strcmpic(h->name, rr->name) == 0) break; }
- if (h == last->next) continue;
-
- /* For IPv4 addresses, add 500 to the random part of the sort key, to ensure
- they sort after IPv6 addresses. */
-
- randoffset = (rr->type == T_A)? 500 : 0;
-
- /* Get the list of textual addresses for this RR. There may be more than one
- if it is an A6 RR. Then loop to handle multiple addresses from an A6 record.
- If there are none, nothing will get done - the record is ignored. */
-
- for (da = dns_address_from_rr(&dnsa, rr); da != NULL; da = da->next)
- {
- /* Set status for an ignorable host. */
-
- #ifndef STAND_ALONE
- if (ignore_target_hosts != NULL &&
- verify_check_this_host(&ignore_target_hosts, NULL, h->name,
- da->address, NULL) == OK)
- {
- DEBUG(D_host_lookup)
- debug_printf("ignored host %s [%s]\n", h->name, da->address);
- status = hstatus_unusable;
- why = hwhy_ignored;
- }
- #endif
-
- /* If the address is already set for this host, it may be that
- we just have a duplicate DNS record. Alternatively, this may be
- a multi-homed host. Search all items with the same host name
- (they will all be together) and if this address is found, skip
- to the next RR. */
-
- if (h->address != NULL)
- {
- int new_sort_key;
- host_item *thishostlast;
- host_item *hh = h;
-
- do
- {
- if (hh->address != NULL && Ustrcmp(CS da->address, hh->address) == 0)
- goto DNS_NEXT_RR; /* Need goto to escape from inner loop */
- thishostlast = hh;
- hh = hh->next;
- }
- while (hh != last->next && strcmpic(hh->name, rr->name) == 0);
-
- /* We have a multi-homed host, since we have a new address for
- an existing name. Create a copy of the current item, and give it
- the new address. RRs can be in arbitrary order, but one is supposed
- to randomize the addresses of multi-homed hosts, so compute a new
- sorting key and do that. [Latest SMTP RFC says not to randomize multi-
- homed hosts, but to rely on the resolver. I'm not happy about that -
- caching in the resolver will not rotate as often as the name server
- does.] */
-
- new_sort_key = h->mx * 1000 + random_number(500) + randoffset;
- hh = store_get(sizeof(host_item));
-
- /* New address goes first: insert the new block after the first one
- (so as not to disturb the original pointer) but put the new address
- in the original block. */
-
- if (new_sort_key < h->sort_key)
- {
- *hh = *h; /* Note: copies the port */
- h->next = hh;
- h->address = da->address;
- h->sort_key = new_sort_key;
- h->status = status;
- h->why = why;
- }
-
- /* Otherwise scan down the addresses for this host to find the
- one to insert after. */
-
- else
- {
- while (h != thishostlast)
- {
- if (new_sort_key < h->next->sort_key) break;
- h = h->next;
- }
- *hh = *h; /* Note: copies the port */
- h->next = hh;
- hh->address = da->address;
- hh->sort_key = new_sort_key;
- hh->status = status;
- hh->why = why;
- }
-
- if (h == last) last = hh; /* Inserted after last */
- }
-
- /* The existing item doesn't have its address set yet, so just set it.
- Ensure that an IPv4 address gets its sort key incremented in case an IPv6
- address is found later. */
-
- else
- {
- h->address = da->address; /* Port should be set already */
- h->status = status;
- h->why = why;
- h->sort_key += randoffset;
- }
- } /* Loop for addresses extracted from one RR */
-
- /* Carry on to the next RR. It would be nice to be able to be able to stop
- when every host on the list has an address, but we can't be sure there won't
- be an additional address for a multi-homed host further down the list, so
- we have to continue to the end. */
-
- DNS_NEXT_RR: continue;
- }
-
-/* Set the default yield to failure */
-
-yield = HOST_FIND_FAILED;
-
-/* If we haven't found all the addresses in the additional section, we
-need to search for A or AAAA records explicitly. The names shouldn't point to
-CNAMES, but we use the general lookup function that handles them, just
-in case. If any lookup gives a soft error, change the default yield.
+/* Now we have to find IP addresses for all the hosts. We have ensured above
+that the names in all the host items are unique. Before release 4.61 we used to
+process records from the additional section in the DNS packet that returned the
+MX or SRV records. However, a DNS name server is free to drop any resource
+records from the additional section. In theory, this has always been a
+potential problem, but it is exacerbated by the advent of IPv6. If a host had
+several IPv4 addresses and some were not in the additional section, at least
+Exim would try the others. However, if a host had both IPv4 and IPv6 addresses
+and all the IPv4 (say) addresses were absent, Exim would try only for a IPv6
+connection, and never try an IPv4 address. When there was only IPv4
+connectivity, this was a disaster that did in practice occur.
+
+So, from release 4.61 onwards, we always search for A and AAAA records
+explicitly. The names shouldn't point to CNAMES, but we use the general lookup
+function that handles them, just in case. If any lookup gives a soft error,
+change the default yield.
For these DNS lookups, we must disable qualify_single and search_parents;
otherwise invalid host names obtained from MX or SRV records can cause trouble
if they happen to match something local. */
-dns_init(FALSE, FALSE);
+yield = HOST_FIND_FAILED; /* Default yield */
+dns_init(FALSE, FALSE, /* Disable qualify_single and search_parents */
+ dnssec_request || dnssec_require);
for (h = host; h != last->next; h = h->next)
{
- if (h->address != NULL || h->status == hstatus_unusable) continue;
- rc = set_address_from_dns(h, &last, ignore_target_hosts, allow_mx_to_ip, NULL);
+ if (h->address != NULL) continue; /* Inserted by a multihomed host */
+ rc = set_address_from_dns(h, &last, ignore_target_hosts, allow_mx_to_ip,
+ NULL, dnssec_request, dnssec_require);
if (rc != HOST_FOUND)
{
h->status = hstatus_unusable;
addresses of a multihomed host, but that should not matter. */
#if HAVE_IPV6
-if (h != last)
+if (h != last && !disable_ipv6)
{
for (h = host; h != last; h = h->next)
{
host_item temp;
host_item *next = h->next;
- if (h->mx != next->mx || /* If next is different MX value */
- (h->sort_key % 1000) < 500 || /* OR this one is IPv6 */
- (next->sort_key % 1000) >= 500) /* OR next is IPv4 */
- continue; /* move on to next */
- temp = *h;
+ if (h->mx != next->mx || /* If next is different MX */
+ h->address == NULL || /* OR this one is unset */
+ Ustrchr(h->address, ':') != NULL || /* OR this one is IPv6 */
+ (next->address != NULL &&
+ Ustrchr(next->address, ':') == NULL)) /* OR next is IPv4 */
+ continue; /* move on to next */
+ temp = *h; /* otherwise, swap */
temp.next = next->next;
*h = *next;
h->next = next;
}
#endif
-/* When running in the test harness, we want the hosts always to be in the same
-order so that the debugging output is the same and can be compared. Having a
-fixed set of "random" numbers doesn't actually achieve this, because the RRs
-come back from the resolver in a random order, so the non-random random numbers
-get used in a different order. We therefore have to sort the hosts that have
-the same MX values. We chose do to this by their name and then by IP address.
-The fact that the sort is slow matters not - this is testing only! */
-
-if (running_in_test_harness)
- {
- BOOL done;
- do
- {
- done = TRUE;
- for (h = host; h != last; h = h->next)
- {
- int c = Ustrcmp(h->name, h->next->name);
- if (c == 0) c = Ustrcmp(h->address, h->next->address);
- if (h->mx == h->next->mx && c > 0)
- {
- host_item *next = h->next;
- host_item temp = *h;
- temp.next = next->next;
- *h = *next;
- h->next = next;
- *next = temp;
- done = FALSE;
- }
- }
- }
- while (!done);
- }
-
/* Remove any duplicate IP addresses and then scan the list of hosts for any
whose IP addresses are on the local host. If any are found, all hosts with the
same or higher MX values are removed. However, if the local host has the lowest
}
}
+out:
+
+dns_init(FALSE, FALSE, FALSE); /* clear the dnssec bit for getaddrbyname */
return yield;
}
BOOL byname = FALSE;
BOOL qualify_single = TRUE;
BOOL search_parents = FALSE;
+BOOL request_dnssec = FALSE;
+BOOL require_dnssec = FALSE;
uschar **argv = USS cargv;
uschar buffer[256];
+disable_ipv6 = FALSE;
primary_hostname = US"";
store_pool = POOL_MAIN;
debug_selector = D_host_lookup|D_interface;
/* So that debug level changes can be done first */
-dns_init(qualify_single, search_parents);
+dns_init(qualify_single, search_parents, FALSE);
printf("Testing host lookup\n");
printf("> ");
whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX;
else if (Ustrcmp(buffer, "srv+mx+a") == 0)
whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX | HOST_FIND_BY_A;
- else if (Ustrcmp(buffer, "qualify_single") == 0) qualify_single = TRUE;
+ else if (Ustrcmp(buffer, "qualify_single") == 0) qualify_single = TRUE;
else if (Ustrcmp(buffer, "no_qualify_single") == 0) qualify_single = FALSE;
- else if (Ustrcmp(buffer, "search_parents") == 0) search_parents = TRUE;
+ else if (Ustrcmp(buffer, "search_parents") == 0) search_parents = TRUE;
else if (Ustrcmp(buffer, "no_search_parents") == 0) search_parents = FALSE;
+ else if (Ustrcmp(buffer, "request_dnssec") == 0) request_dnssec = TRUE;
+ else if (Ustrcmp(buffer, "no_request_dnssec") == 0) request_dnssec = FALSE;
+ else if (Ustrcmp(buffer, "require_dnssec") == 0) require_dnssec = TRUE;
+ else if (Ustrcmp(buffer, "no_reqiret_dnssec") == 0) require_dnssec = FALSE;
else if (Ustrcmp(buffer, "test_harness") == 0)
running_in_test_harness = !running_in_test_harness;
+ else if (Ustrcmp(buffer, "ipv6") == 0) disable_ipv6 = !disable_ipv6;
else if (Ustrcmp(buffer, "res_debug") == 0)
{
_res.options ^= RES_DEBUG;
if (qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
if (search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
- rc = byname?
- host_find_byname(&h, NULL, &fully_qualified_name, TRUE)
- :
- host_find_bydns(&h, NULL, flags, US"smtp", NULL, NULL,
- &fully_qualified_name, NULL);
+ rc = byname
+ ? host_find_byname(&h, NULL, flags, &fully_qualified_name, TRUE)
+ : host_find_bydns(&h, NULL, flags, US"smtp", NULL, NULL,
+ request_dnssec ? &h.name : NULL,
+ require_dnssec ? &h.name : NULL,
+ &fully_qualified_name, NULL);
if (rc == HOST_FIND_FAILED) printf("Failed\n");
else if (rc == HOST_FIND_AGAIN) printf("Again\n");
}
#endif /* STAND_ALONE */
+/* vi: aw ai sw=2
+*/
/* End of host.c */
git://git.exim.org / exim.git / blobdiff