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heimdal/lib/krb5/krbhst.c
Nicolas Williams 305ab03155 krb5: Fix DNS SRV name collision handling
2024-09-03 15:14:42 -04:00

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/*
* Copyright (c) 2001 - 2003 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Portions Copyright (c) 2010 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "krb5_locl.h"
#include <resolve.h>
#include "locate_plugin.h"
static int
string_to_proto(const char *string)
{
if(strcasecmp(string, "udp") == 0)
return KRB5_KRBHST_UDP;
else if(strcasecmp(string, "tcp") == 0)
return KRB5_KRBHST_TCP;
else if(strcasecmp(string, "http") == 0)
return KRB5_KRBHST_HTTP;
return -1;
}
#define YOUR_DNS_NEEDS_IMM_ATTENTION "your-dns-needs-immediate-attention."
static int
is_invalid_tld_srv_target(const char *target)
{
if (strncmp(YOUR_DNS_NEEDS_IMM_ATTENTION, target,
sizeof(YOUR_DNS_NEEDS_IMM_ATTENTION) - 1) != 0)
return 0;
target += sizeof(YOUR_DNS_NEEDS_IMM_ATTENTION) - 1;
if (target[0] == '\0' || target[0] == '.')
return 0; /* malformed; should be followed by a TLD */
target = strchr(target, '.');
if (target == NULL)
return 0; /* malformed; should end in a '.' */
if (target[1] != '\0')
return 0; /* malformed; should be followed by just one label (the TLD) */
return 1;
}
/*
* set `res' and `count' to the result of looking up SRV RR in DNS for
* `proto', `proto', `realm' using `dns_type'.
* if `port' != 0, force that port number
*/
static krb5_error_code
srv_find_realm(krb5_context context, krb5_krbhst_info ***res, int *count,
const char *realm, const char *dns_type, const char *sitename,
const char *proto, const char *service, int port)
{
char domain[1024];
struct rk_dns_reply *r;
struct rk_resource_record *rr;
int num_srv;
int proto_num;
int def_port;
*res = NULL;
*count = 0;
proto_num = string_to_proto(proto);
if(proto_num < 0) {
krb5_set_error_message(context, EINVAL,
N_("unknown protocol `%s' to lookup", ""),
proto);
return EINVAL;
}
if(proto_num == KRB5_KRBHST_HTTP)
def_port = ntohs(krb5_getportbyname (context, "http", "tcp", 80));
else if(port == 0)
def_port = ntohs(krb5_getportbyname (context, service, proto, 88));
else
def_port = port;
if (sitename)
snprintf(domain, sizeof(domain), "_%s._%s.%s._sites.%s.",
service, proto, sitename, realm);
else
snprintf(domain, sizeof(domain), "_%s._%s.%s.", service, proto, realm);
r = rk_dns_lookup(domain, dns_type);
if(r == NULL) {
_krb5_debug(context, 0,
"DNS lookup failed domain: %s", domain);
return KRB5_KDC_UNREACH;
}
for(num_srv = 0, rr = r->head; rr; rr = rr->next)
if(rr->type == rk_ns_t_srv)
num_srv++;
if (num_srv == 0) {
_krb5_debug(context, 0,
"DNS SRV RR lookup domain nodata: %s", domain);
rk_dns_free_data(r);
return KRB5_KDC_UNREACH;
}
*res = malloc(num_srv * sizeof(**res));
if(*res == NULL) {
rk_dns_free_data(r);
return krb5_enomem(context);
}
rk_dns_srv_order(r);
for(num_srv = 0, rr = r->head; rr; rr = rr->next)
if(rr->type == rk_ns_t_srv) {
krb5_krbhst_info *hi = NULL;
size_t len;
/* Test for top-level domain controlled interruptions */
if (is_invalid_tld_srv_target(rr->u.srv->target)) {
krb5_warnx(context,
"Domain lookup failed: "
"Realm %s needs immediate attention "
"see https://icann.org/namecollision",
realm);
return KRB5_KDC_UNREACH;
}
len = strlen(rr->u.srv->target);
hi = calloc(1, sizeof(*hi) + len);
if(hi == NULL) {
rk_dns_free_data(r);
while(--num_srv >= 0)
free((*res)[num_srv]);
free(*res);
*res = NULL;
return krb5_enomem(context);
}
(*res)[num_srv++] = hi;
hi->proto = proto_num;
hi->def_port = def_port;
if (port != 0)
hi->port = port;
else
hi->port = rr->u.srv->port;
strlcpy(hi->hostname, rr->u.srv->target, len + 1);
}
*count = num_srv;
rk_dns_free_data(r);
return 0;
}
struct krb5_krbhst_data {
const char *config_param;
const char *srv_label;
char *realm;
unsigned int flags;
int def_port;
int port; /* hardwired port number if != 0 */
#define KD_CONFIG 0x0001
#define KD_SRV_UDP 0x0002
#define KD_SRV_TCP 0x0004
#define KD_SITE_SRV_UDP 0x0008
#define KD_SITE_SRV_TCP 0x0010
#define KD_SRV_HTTP 0x0020
#define KD_SRV_KKDCP 0x0040
#define KD_FALLBACK 0x0080
#define KD_CONFIG_EXISTS 0x0100
#define KD_LARGE_MSG 0x0200
#define KD_PLUGIN 0x0400
#define KD_HOSTNAMES 0x0800
krb5_error_code (*get_next)(krb5_context, struct krb5_krbhst_data *,
krb5_krbhst_info**);
char *hostname;
char *sitename;
unsigned int fallback_count;
struct krb5_krbhst_info *hosts, **index, **end;
};
static krb5_boolean
krbhst_empty(const struct krb5_krbhst_data *kd)
{
return kd->index == &kd->hosts;
}
/*
* Return the default protocol for the `kd' (either TCP or UDP)
*/
static int
krbhst_get_default_proto(struct krb5_krbhst_data *kd)
{
if (kd->flags & KD_LARGE_MSG)
return KRB5_KRBHST_TCP;
return KRB5_KRBHST_UDP;
}
static int
krbhst_get_default_port(struct krb5_krbhst_data *kd)
{
return kd->def_port;
}
/*
*
*/
KRB5_LIB_FUNCTION const char * KRB5_LIB_CALL
_krb5_krbhst_get_realm(krb5_krbhst_handle handle)
{
return handle->realm;
}
/*
* parse `spec' into a krb5_krbhst_info, defaulting the port to `def_port'
* and forcing it to `port' if port != 0
*/
static struct krb5_krbhst_info*
parse_hostspec(krb5_context context, struct krb5_krbhst_data *kd,
const char *spec, int def_port, int port)
{
const char *p = spec, *q;
struct krb5_krbhst_info *hi;
hi = calloc(1, sizeof(*hi) + strlen(spec));
if(hi == NULL)
return NULL;
hi->proto = krbhst_get_default_proto(kd);
if(strncmp(p, "http://", 7) == 0){
hi->proto = KRB5_KRBHST_HTTP;
p += 7;
} else if(strncmp(p, "http/", 5) == 0) {
hi->proto = KRB5_KRBHST_HTTP;
p += 5;
def_port = ntohs(krb5_getportbyname (context, "http", "tcp", 80));
}else if(strncmp(p, "tcp/", 4) == 0){
hi->proto = KRB5_KRBHST_TCP;
p += 4;
} else if(strncmp(p, "udp/", 4) == 0) {
hi->proto = KRB5_KRBHST_UDP;
p += 4;
}
if (p[0] == '[' && (q = strchr(p, ']')) != NULL) {
/* if address looks like [foo:bar] or [foo:bar]: its a ipv6
address, strip of [] */
memcpy(hi->hostname, &p[1], q - p - 1);
hi->hostname[q - p - 1] = '\0';
p = q + 1;
/* get trailing : */
if (p[0] == ':')
p++;
} else if(strsep_copy(&p, ":", hi->hostname, strlen(spec) + 1) < 0) {
/* copy everything before : */
free(hi);
return NULL;
}
/* get rid of trailing /, and convert to lower case */
hi->hostname[strcspn(hi->hostname, "/")] = '\0';
strlwr(hi->hostname);
hi->port = hi->def_port = def_port;
if(p != NULL && p[0]) {
char *end;
hi->port = strtol(p, &end, 0);
if(end == p) {
free(hi);
return NULL;
}
}
if (port)
hi->port = port;
return hi;
}
KRB5_LIB_FUNCTION void KRB5_LIB_CALL
_krb5_free_krbhst_info(krb5_krbhst_info *hi)
{
if (hi->ai != NULL)
freeaddrinfo(hi->ai);
free(hi);
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
_krb5_krbhost_info_move(krb5_context context,
krb5_krbhst_info *from,
krb5_krbhst_info **to)
{
size_t hostnamelen = strlen(from->hostname);
/* trailing NUL is included in structure */
*to = calloc(1, sizeof(**to) + hostnamelen);
if (*to == NULL)
return krb5_enomem(context);
(*to)->proto = from->proto;
(*to)->port = from->port;
(*to)->def_port = from->def_port;
(*to)->ai = from->ai;
from->ai = NULL;
(*to)->next = NULL;
memcpy((*to)->hostname, from->hostname, hostnamelen + 1);
return 0;
}
static void
append_host_hostinfo(struct krb5_krbhst_data *kd, struct krb5_krbhst_info *host)
{
struct krb5_krbhst_info *h;
for(h = kd->hosts; h; h = h->next)
if(h->proto == host->proto &&
h->port == host->port &&
strcmp(h->hostname, host->hostname) == 0) {
_krb5_free_krbhst_info(host);
return;
}
/*
* We should always initialize kd->end in common_init(), but static
* analyzers may not see that we do, and the compiler might conclude
* there's UB here.
*/
if (kd->end)
*kd->end = host;
kd->end = &host->next;
}
static krb5_error_code
append_host_string(krb5_context context, struct krb5_krbhst_data *kd,
const char *host, int def_port, int port)
{
struct krb5_krbhst_info *hi;
hi = parse_hostspec(context, kd, host, def_port, port);
if(hi == NULL)
return krb5_enomem(context);
append_host_hostinfo(kd, hi);
return 0;
}
/*
* return a readable representation of `host' in `hostname, hostlen'
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_krbhst_format_string(krb5_context context, const krb5_krbhst_info *host,
char *hostname, size_t hostlen)
{
const char *proto = "";
if(host->proto == KRB5_KRBHST_TCP)
proto = "tcp/";
else if(host->proto == KRB5_KRBHST_HTTP)
proto = "http://";
if (host->port != host->def_port)
snprintf(hostname, hostlen, "%s%s:%d", proto, host->hostname, (int)host->port);
else
snprintf(hostname, hostlen, "%s%s", proto, host->hostname);
return 0;
}
/*
* create a getaddrinfo `hints' based on `proto'
*/
static void
make_hints(struct addrinfo *hints, int proto)
{
memset(hints, 0, sizeof(*hints));
hints->ai_family = AF_UNSPEC;
switch(proto) {
case KRB5_KRBHST_UDP :
hints->ai_socktype = SOCK_DGRAM;
break;
case KRB5_KRBHST_HTTP :
case KRB5_KRBHST_TCP :
hints->ai_socktype = SOCK_STREAM;
break;
}
}
/**
* Return an `struct addrinfo *' for a KDC host.
*
* Returns an the struct addrinfo in in that corresponds to the
* information in `host'. free:ing is handled by krb5_krbhst_free, so
* the returned ai must not be released.
*
* @ingroup krb5
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_krbhst_get_addrinfo(krb5_context context, krb5_krbhst_info *host,
struct addrinfo **ai)
{
int ret = 0;
if (host->ai == NULL) {
struct addrinfo hints;
char portstr[NI_MAXSERV];
snprintf (portstr, sizeof(portstr), "%d", host->port);
make_hints(&hints, host->proto);
if (krb5_config_get_bool(context, NULL, "libdefaults", "block_dns",
NULL)) {
hints.ai_flags &= ~AI_CANONNAME;
hints.ai_flags |= AI_NUMERICHOST|AI_NUMERICSERV;
}
ret = getaddrinfo(host->hostname, portstr, &hints, &host->ai);
if (ret) {
ret = krb5_eai_to_heim_errno(ret, errno);
goto out;
}
}
out:
*ai = host->ai;
return ret;
}
static krb5_boolean
get_next(struct krb5_krbhst_data *kd, krb5_krbhst_info **host)
{
struct krb5_krbhst_info *hi = kd ? *kd->index : NULL;
if(hi != NULL) {
*host = hi;
kd->index = &(*kd->index)->next;
return TRUE;
}
return FALSE;
}
static void
srv_get_hosts(krb5_context context, struct krb5_krbhst_data *kd,
const char *sitename, const char *proto, const char *service)
{
krb5_error_code ret;
krb5_krbhst_info **res;
int count, i;
if (krb5_realm_is_lkdc(kd->realm))
return;
ret = srv_find_realm(context, &res, &count, kd->realm, "SRV",
sitename, proto, service, kd->port);
_krb5_debug(context, 2, "searching DNS for realm %s %s.%s -> %d",
kd->realm, proto, service, ret);
if (ret)
return;
for(i = 0; i < count; i++)
append_host_hostinfo(kd, res[i]);
free(res);
}
/*
* read the configuration for `conf_string', defaulting to kd->def_port and
* forcing it to `kd->port' if kd->port != 0
*/
static void
config_get_hosts(krb5_context context, struct krb5_krbhst_data *kd,
const char *conf_string)
{
int i;
char **hostlist;
hostlist = krb5_config_get_strings(context, NULL,
"realms", kd->realm, conf_string, NULL);
_krb5_debug(context, 2, "configuration file for realm %s%s found",
kd->realm, hostlist ? "" : " not");
if(hostlist == NULL)
return;
kd->flags |= KD_CONFIG_EXISTS;
for(i = 0; hostlist && hostlist[i] != NULL; i++)
append_host_string(context, kd, hostlist[i], kd->def_port, kd->port);
krb5_config_free_strings(hostlist);
}
/*
* as a fallback, look for `serv_string.kd->realm' (typically
* kerberos.REALM, kerberos-1.REALM, ...
* `port' is the default port for the service, and `proto' the
* protocol
*/
static krb5_error_code
fallback_get_hosts(krb5_context context, struct krb5_krbhst_data *kd,
const char *serv_string, int port, int proto)
{
char *host = NULL;
int ret;
struct addrinfo *ai;
struct addrinfo hints;
char portstr[NI_MAXSERV];
ret = krb5_config_get_bool_default(context, NULL, KRB5_FALLBACK_DEFAULT,
"libdefaults", "use_fallback", NULL);
if (!ret) {
kd->flags |= KD_FALLBACK;
return 0;
}
_krb5_debug(context, 2, "fallback lookup %d for realm %s (service %s)",
kd->fallback_count, kd->realm, serv_string);
/*
* Don't try forever in case the DNS server keep returning us
* entries (like wildcard entries or the .nu TLD)
*
* Also don't try LKDC realms since fallback wont work on them at all.
*/
if(kd->fallback_count >= 5 || krb5_realm_is_lkdc(kd->realm)) {
kd->flags |= KD_FALLBACK;
return 0;
}
if(kd->fallback_count == 0)
ret = asprintf(&host, "%s.%s.", serv_string, kd->realm);
else
ret = asprintf(&host, "%s-%d.%s.",
serv_string, kd->fallback_count, kd->realm);
if (ret < 0 || host == NULL)
return krb5_enomem(context);
make_hints(&hints, proto);
snprintf(portstr, sizeof(portstr), "%d", port);
if (krb5_config_get_bool(context, NULL, "libdefaults", "block_dns",
NULL)) {
hints.ai_flags &= ~AI_CANONNAME;
hints.ai_flags |= AI_NUMERICHOST|AI_NUMERICSERV;
}
ret = getaddrinfo(host, portstr, &hints, &ai);
if (ret) {
/* no more hosts, so we're done here */
free(host);
kd->flags |= KD_FALLBACK;
} else {
struct krb5_krbhst_info *hi;
size_t hostlen;
/* Check for ICANN gTLD Name Collision address (127.0.53.53) */
if (ai->ai_family == AF_INET) {
struct sockaddr_in *sin = (struct sockaddr_in *)ai->ai_addr;
if (sin->sin_addr.s_addr == htonl(0x7f003535)) {
krb5_warnx(context,
"Fallback lookup failed: "
"Realm %s needs immediate attention "
"see https://icann.org/namecollision",
kd->realm);
free(host);
freeaddrinfo(ai);
return KRB5_KDC_UNREACH;
}
}
hostlen = strlen(host);
hi = calloc(1, sizeof(*hi) + hostlen);
if(hi == NULL) {
free(host);
freeaddrinfo(ai);
return krb5_enomem(context);
}
hi->proto = proto;
hi->port = hi->def_port = port;
hi->ai = ai;
memmove(hi->hostname, host, hostlen);
hi->hostname[hostlen] = '\0';
free(host);
append_host_hostinfo(kd, hi);
kd->fallback_count++;
}
return 0;
}
/*
* Fetch hosts from plugin
*/
static krb5_error_code
add_plugin_host(struct krb5_krbhst_data *kd,
const char *host,
const char *port,
int portnum,
int proto)
{
struct krb5_krbhst_info *hi;
struct addrinfo hints, *ai;
size_t hostlen;
int ret;
make_hints(&hints, proto);
ret = getaddrinfo(host, port, &hints, &ai);
if (ret)
return 0;
hostlen = strlen(host);
hi = calloc(1, sizeof(*hi) + hostlen);
if (hi == NULL) {
freeaddrinfo(ai);
return ENOMEM;
}
hi->proto = proto;
hi->port = hi->def_port = portnum;
hi->ai = ai;
memmove(hi->hostname, host, hostlen);
hi->hostname[hostlen] = '\0';
append_host_hostinfo(kd, hi);
return 0;
}
static krb5_error_code
add_locate(void *ctx, int type, struct sockaddr *addr)
{
struct krb5_krbhst_data *kd = ctx;
char host[NI_MAXHOST], port[NI_MAXSERV];
socklen_t socklen;
krb5_error_code ret;
int proto, portnum;
socklen = socket_sockaddr_size(addr);
portnum = socket_get_port(addr);
ret = getnameinfo(addr, socklen, host, sizeof(host), port, sizeof(port),
NI_NUMERICHOST|NI_NUMERICSERV|NI_NUMERICSCOPE);
if (ret != 0)
return 0;
if (kd->port)
snprintf(port, sizeof(port), "%d", kd->port);
else if (atoi(port) == 0)
snprintf(port, sizeof(port), "%d", krbhst_get_default_port(kd));
proto = krbhst_get_default_proto(kd);
ret = add_plugin_host(kd, host, port, portnum, proto);
if (ret)
return ret;
/*
* This is really kind of broken and should be solved a different
* way, some sites block UDP, and we don't, in the general case,
* fall back to TCP, that should also be done. But since that
* should require us to invert the whole "find kdc" stack, let put
* this in for now.
*/
if (proto == KRB5_KRBHST_UDP) {
ret = add_plugin_host(kd, host, port, portnum, KRB5_KRBHST_TCP);
if (ret)
return ret;
}
return 0;
}
struct plctx {
enum locate_service_type type;
struct krb5_krbhst_data *kd;
unsigned long flags;
};
static KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
plcallback(krb5_context context,
const void *plug, void *plugctx, void *userctx)
{
const krb5plugin_service_locate_ftable *locate = plug;
struct plctx *plctx = userctx;
if (locate->minor_version >= KRB5_PLUGIN_LOCATE_VERSION_2)
return locate->lookup(plugctx, plctx->flags, plctx->type, plctx->kd->realm, 0, 0, add_locate, plctx->kd);
if (plctx->flags & KRB5_PLF_ALLOW_HOMEDIR)
return locate->old_lookup(plugctx, plctx->type, plctx->kd->realm, 0, 0, add_locate, plctx->kd);
return KRB5_PLUGIN_NO_HANDLE;
}
static const char *const locate_plugin_deps[] = { "krb5", NULL };
static const struct heim_plugin_data
locate_plugin_data = {
"krb5",
KRB5_PLUGIN_LOCATE,
KRB5_PLUGIN_LOCATE_VERSION_0,
locate_plugin_deps,
krb5_get_instance
};
static void
plugin_get_hosts(krb5_context context,
struct krb5_krbhst_data *kd,
enum locate_service_type type)
{
struct plctx ctx = { type, kd, 0 };
/*
* XXX Need a way to pass this through -- unsure if any of this is
* useful without DNS, though.
*/
if (krb5_config_get_bool(context, NULL, "libdefaults", "block_dns", NULL))
return;
if (_krb5_homedir_access(context))
ctx.flags |= KRB5_PLF_ALLOW_HOMEDIR;
_krb5_plugin_run_f(context, &locate_plugin_data,
0, &ctx, plcallback);
}
/*
*
*/
static void
hostnames_get_hosts(krb5_context context,
struct krb5_krbhst_data *kd,
const char *type)
{
kd->flags |= KD_HOSTNAMES;
if (kd->hostname)
append_host_string(context, kd, kd->hostname, kd->def_port, kd->port);
}
/*
*
*/
static krb5_error_code
kdc_get_next(krb5_context context,
struct krb5_krbhst_data *kd,
krb5_krbhst_info **host)
{
krb5_error_code ret;
if ((kd->flags & KD_HOSTNAMES) == 0) {
hostnames_get_hosts(context, kd, "kdc");
if(get_next(kd, host))
return 0;
}
if ((kd->flags & KD_PLUGIN) == 0) {
plugin_get_hosts(context, kd, locate_service_kdc);
kd->flags |= KD_PLUGIN;
if(get_next(kd, host))
return 0;
}
if((kd->flags & KD_CONFIG) == 0) {
config_get_hosts(context, kd, kd->config_param);
kd->flags |= KD_CONFIG;
if(get_next(kd, host))
return 0;
}
if (kd->flags & KD_CONFIG_EXISTS) {
_krb5_debug(context, 1,
"Configuration exists for realm %s, wont go to DNS",
kd->realm);
return KRB5_KDC_UNREACH;
}
if (!krb5_config_get_bool(context, NULL, "libdefaults", "block_dns",
NULL) &&
context->srv_lookup) {
if(kd->sitename && (kd->flags & KD_SITE_SRV_TCP) == 0) {
srv_get_hosts(context, kd, kd->sitename, "tcp", "kerberos");
kd->flags |= KD_SITE_SRV_TCP;
if(get_next(kd, host))
return 0;
}
if((kd->flags & KD_SRV_UDP) == 0 && (kd->flags & KD_LARGE_MSG) == 0) {
srv_get_hosts(context, kd, NULL, "udp", kd->srv_label);
kd->flags |= KD_SRV_UDP;
if(get_next(kd, host))
return 0;
}
if((kd->flags & KD_SRV_TCP) == 0) {
srv_get_hosts(context, kd, NULL, "tcp", kd->srv_label);
kd->flags |= KD_SRV_TCP;
if(get_next(kd, host))
return 0;
}
if((kd->flags & KD_SRV_HTTP) == 0) {
srv_get_hosts(context, kd, NULL, "http", kd->srv_label);
kd->flags |= KD_SRV_HTTP;
if(get_next(kd, host))
return 0;
}
}
while((kd->flags & KD_FALLBACK) == 0) {
ret = fallback_get_hosts(context, kd, "kerberos",
kd->def_port,
krbhst_get_default_proto(kd));
if(ret)
return ret;
if(get_next(kd, host))
return 0;
}
_krb5_debug(context, 0, "No KDC entries found for %s", kd->realm);
return KRB5_KDC_UNREACH; /* XXX */
}
static krb5_error_code
admin_get_next(krb5_context context,
struct krb5_krbhst_data *kd,
krb5_krbhst_info **host)
{
krb5_error_code ret;
if ((kd->flags & KD_PLUGIN) == 0) {
plugin_get_hosts(context, kd, locate_service_kadmin);
kd->flags |= KD_PLUGIN;
if(get_next(kd, host))
return 0;
}
if((kd->flags & KD_CONFIG) == 0) {
config_get_hosts(context, kd, kd->config_param);
kd->flags |= KD_CONFIG;
if(get_next(kd, host))
return 0;
}
if (kd->flags & KD_CONFIG_EXISTS) {
_krb5_debug(context, 1,
"Configuration exists for realm %s, wont go to DNS",
kd->realm);
return KRB5_KDC_UNREACH;
}
if (!krb5_config_get_bool(context, NULL, "libdefaults", "block_dns",
NULL) &&
context->srv_lookup) {
if((kd->flags & KD_SRV_TCP) == 0) {
srv_get_hosts(context, kd, NULL, "tcp", kd->srv_label);
kd->flags |= KD_SRV_TCP;
if(get_next(kd, host))
return 0;
}
}
if (krbhst_empty(kd)
&& (kd->flags & KD_FALLBACK) == 0) {
ret = fallback_get_hosts(context, kd, "kerberos",
kd->def_port,
krbhst_get_default_proto(kd));
if(ret)
return ret;
kd->flags |= KD_FALLBACK;
if(get_next(kd, host))
return 0;
}
_krb5_debug(context, 0, "No admin entries found for realm %s", kd->realm);
return KRB5_KDC_UNREACH; /* XXX */
}
static krb5_error_code
kpasswd_get_next(krb5_context context,
struct krb5_krbhst_data *kd,
krb5_krbhst_info **host)
{
krb5_error_code ret;
if ((kd->flags & KD_PLUGIN) == 0) {
plugin_get_hosts(context, kd, locate_service_kpasswd);
kd->flags |= KD_PLUGIN;
if(get_next(kd, host))
return 0;
}
if((kd->flags & KD_CONFIG) == 0) {
config_get_hosts(context, kd, kd->config_param);
kd->flags |= KD_CONFIG;
if(get_next(kd, host))
return 0;
}
if (kd->flags & KD_CONFIG_EXISTS) {
_krb5_debug(context, 1,
"Configuration exists for realm %s, wont go to DNS",
kd->realm);
return KRB5_KDC_UNREACH;
}
if (!krb5_config_get_bool(context, NULL, "libdefaults", "block_dns",
NULL) &&
context->srv_lookup) {
if((kd->flags & KD_SRV_UDP) == 0) {
srv_get_hosts(context, kd, NULL, "udp", kd->srv_label);
kd->flags |= KD_SRV_UDP;
if(get_next(kd, host))
return 0;
}
if((kd->flags & KD_SRV_TCP) == 0) {
srv_get_hosts(context, kd, NULL, "tcp", kd->srv_label);
kd->flags |= KD_SRV_TCP;
if(get_next(kd, host))
return 0;
}
}
/* no matches -> try admin */
if (krbhst_empty(kd)) {
kd->flags = 0;
kd->port = kd->def_port;
kd->get_next = admin_get_next;
ret = (*kd->get_next)(context, kd, host);
if (ret == 0)
(*host)->proto = krbhst_get_default_proto(kd);
return ret;
}
_krb5_debug(context, 0, "No kpasswd entries found for realm %s", kd->realm);
return KRB5_KDC_UNREACH;
}
static void KRB5_CALLCONV
krbhost_dealloc(void *ptr)
{
struct krb5_krbhst_data *handle = (struct krb5_krbhst_data *)ptr;
krb5_krbhst_info *h, *next;
for (h = handle->hosts; h != NULL; h = next) {
next = h->next;
_krb5_free_krbhst_info(h);
}
if (handle->hostname)
free(handle->hostname);
if (handle->sitename)
free(handle->sitename);
free(handle->realm);
}
static struct krb5_krbhst_data*
common_init(krb5_context context,
const char *config_param,
const char *srv_label,
const char *service,
const char *realm,
int flags)
{
struct krb5_krbhst_data *kd;
if ((kd = heim_alloc(sizeof(*kd), "krbhst-context", krbhost_dealloc)) == NULL)
return NULL;
if((kd->realm = strdup(realm)) == NULL) {
heim_release(kd);
return NULL;
}
kd->config_param = config_param;
kd->srv_label = srv_label;
_krb5_debug(context, 2, "Trying to find service %s for realm %s flags %x",
service, realm, flags);
/* For 'realms' without a . do not even think of going to DNS */
if (!strchr(realm, '.'))
kd->flags |= KD_CONFIG_EXISTS;
if (flags & KRB5_KRBHST_FLAGS_LARGE_MSG)
kd->flags |= KD_LARGE_MSG;
kd->end = kd->index = &kd->hosts;
return kd;
}
/*
* initialize `handle' to look for hosts of type `type' in realm `realm'
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_krbhst_init(krb5_context context,
const char *realm,
unsigned int type,
krb5_krbhst_handle *handle)
{
return krb5_krbhst_init_flags(context, realm, type, 0, handle);
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_krbhst_init_flags(krb5_context context,
const char *realm,
unsigned int type,
int flags,
krb5_krbhst_handle *handle)
{
struct krb5_krbhst_data *kd;
krb5_error_code (*next)(krb5_context, struct krb5_krbhst_data *,
krb5_krbhst_info **);
int def_port;
const char *config_param;
const char *srv_label;
const char *service;
*handle = NULL;
switch(type) {
case KRB5_KRBHST_KDC:
next = kdc_get_next;
def_port = ntohs(krb5_getportbyname(context, "kerberos", "udp", 88));
config_param = "kdc";
srv_label = "kerberos";
service = "kdc";
break;
case KRB5_KRBHST_ADMIN:
next = admin_get_next;
def_port = ntohs(krb5_getportbyname(context, "kerberos-adm",
"tcp", 749));
config_param = "admin_server";
srv_label = "kerberos-adm";
service = "admin";
break;
case KRB5_KRBHST_READONLY_ADMIN:
next = admin_get_next;
def_port = ntohs(krb5_getportbyname(context, "kerberos-adm",
"tcp", 749));
config_param = "readonly_admin_server";
srv_label = "kerberos-adm-readonly";
service = "admin";
break;
case KRB5_KRBHST_CHANGEPW:
next = kpasswd_get_next;
def_port = ntohs(krb5_getportbyname(context, "kpasswd", "udp",
KPASSWD_PORT));
config_param = "kpasswd_server";
srv_label = "kpasswd";
service = "change_password";
break;
case KRB5_KRBHST_TKTBRIDGEAP:
next = kdc_get_next;
def_port = ntohs(krb5_getportbyname(context, "kerberos", "tcp", 88));
config_param = "tktbridgeap";
srv_label = "kerberos-tkt-bridge";
service = "kdc";
break;
default:
krb5_set_error_message(context, ENOTTY,
N_("unknown krbhst type (%u)", ""), type);
return ENOTTY;
}
if((kd = common_init(context, config_param, srv_label, service, realm,
flags)) == NULL)
return ENOMEM;
kd->get_next = next;
kd->def_port = def_port;
*handle = kd;
return 0;
}
/*
* return the next host information from `handle' in `host'
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_krbhst_next(krb5_context context,
krb5_krbhst_handle handle,
krb5_krbhst_info **host)
{
if(get_next(handle, host))
return 0;
return (*handle->get_next)(context, handle, host);
}
/*
* return the next host information from `handle' as a host name
* in `hostname' (or length `hostlen)
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_krbhst_next_as_string(krb5_context context,
krb5_krbhst_handle handle,
char *hostname,
size_t hostlen)
{
krb5_error_code ret;
krb5_krbhst_info *host;
ret = krb5_krbhst_next(context, handle, &host);
if(ret)
return ret;
return krb5_krbhst_format_string(context, host, hostname, hostlen);
}
/*
*
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_krbhst_set_hostname(krb5_context context,
krb5_krbhst_handle handle,
const char *hostname)
{
if (handle->hostname)
free(handle->hostname);
handle->hostname = strdup(hostname);
if (handle->hostname == NULL)
return ENOMEM;
return 0;
}
krb5_error_code KRB5_LIB_FUNCTION
krb5_krbhst_set_sitename(krb5_context context,
krb5_krbhst_handle handle,
const char *sitename)
{
if (handle->sitename)
free(handle->sitename);
handle->sitename = strdup(sitename);
if (handle->sitename == NULL)
return krb5_enomem(context);
return 0;
}
KRB5_LIB_FUNCTION void KRB5_LIB_CALL
krb5_krbhst_reset(krb5_context context, krb5_krbhst_handle handle)
{
handle->index = &handle->hosts;
}
KRB5_LIB_FUNCTION void KRB5_LIB_CALL
krb5_krbhst_free(krb5_context context, krb5_krbhst_handle handle)
{
heim_release(handle);
}
#ifndef HEIMDAL_SMALLER
/* backwards compatibility ahead */
static krb5_error_code
gethostlist(krb5_context context, const char *realm,
unsigned int type, char ***hostlist)
{
krb5_error_code ret;
int nhost = 0;
krb5_krbhst_handle handle;
char host[MAXHOSTNAMELEN];
krb5_krbhst_info *hostinfo;
ret = krb5_krbhst_init(context, realm, type, &handle);
if (ret)
return ret;
while (krb5_krbhst_next(context, handle, &hostinfo) == 0)
nhost++;
if (nhost == 0) {
krb5_set_error_message(context, KRB5_KDC_UNREACH,
N_("No KDC found for realm %s", ""), realm);
krb5_krbhst_free(context, handle);
return KRB5_KDC_UNREACH;
}
*hostlist = calloc(nhost + 1, sizeof(**hostlist));
if (*hostlist == NULL) {
krb5_krbhst_free(context, handle);
return krb5_enomem(context);
}
krb5_krbhst_reset(context, handle);
nhost = 0;
while (krb5_krbhst_next_as_string(context, handle,
host, sizeof(host)) == 0) {
if (((*hostlist)[nhost++] = strdup(host)) == NULL) {
krb5_free_krbhst(context, *hostlist);
krb5_krbhst_free(context, handle);
return krb5_enomem(context);
}
}
(*hostlist)[nhost] = NULL;
krb5_krbhst_free(context, handle);
return 0;
}
/*
* Return a malloced list of kadmin-hosts for `realm' in `hostlist'
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_get_krb_admin_hst(krb5_context context,
const krb5_realm *realm,
char ***hostlist)
{
return gethostlist(context, *realm, KRB5_KRBHST_ADMIN, hostlist);
}
/*
* Return a malloced list of writable kadmin-hosts for `realm' in `hostlist'
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_get_krb_readonly_admin_hst(krb5_context context,
const krb5_realm *realm,
char ***hostlist)
{
return gethostlist(context, *realm, KRB5_KRBHST_READONLY_ADMIN, hostlist);
}
/*
* return an malloced list of changepw-hosts for `realm' in `hostlist'
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_get_krb_changepw_hst (krb5_context context,
const krb5_realm *realm,
char ***hostlist)
{
return gethostlist(context, *realm, KRB5_KRBHST_CHANGEPW, hostlist);
}
/*
* return an malloced list of 524-hosts for `realm' in `hostlist'
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_get_krb524hst (krb5_context context,
const krb5_realm *realm,
char ***hostlist)
{
return gethostlist(context, *realm, KRB5_KRBHST_KRB524, hostlist);
}
/*
* return an malloced list of KDC's for `realm' in `hostlist'
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_get_krbhst (krb5_context context,
const krb5_realm *realm,
char ***hostlist)
{
return gethostlist(context, *realm, KRB5_KRBHST_KDC, hostlist);
}
/*
* free all the memory allocated in `hostlist'
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_free_krbhst (krb5_context context,
char **hostlist)
{
char **p;
for (p = hostlist; *p; ++p)
free (*p);
free (hostlist);
return 0;
}
#endif /* HEIMDAL_SMALLER */
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