/*
* Copyright (c) 1997 - 2001, 2003 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* 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"
/* this is an attempt at one of the most horrible `compression'
schemes that has ever been invented; it's so amazingly brain-dead
that words can not describe it, and all this just to save a few
silly bytes */
struct tr_realm {
char *realm;
unsigned leading_space:1;
unsigned leading_slash:1;
unsigned trailing_dot:1;
struct tr_realm *next;
};
static void
free_realms(struct tr_realm *r)
{
struct tr_realm *p;
while(r){
p = r;
r = r->next;
free(p->realm);
free(p);
}
}
static int
make_path(krb5_context context, struct tr_realm *r,
const char *from, const char *to)
{
struct tr_realm *tmp;
const char *p;
if(strlen(from) < strlen(to)){
const char *str;
str = from;
from = to;
to = str;
}
if(strcmp(from + strlen(from) - strlen(to), to) == 0){
p = from;
while(1){
p = strchr(p, '.');
if(p == NULL) {
krb5_clear_error_message (context);
return KRB5KDC_ERR_POLICY;
}
p++;
if(strcmp(p, to) == 0)
break;
tmp = calloc(1, sizeof(*tmp));
if(tmp == NULL)
return krb5_enomem(context);
tmp->next = r->next;
r->next = tmp;
tmp->realm = strdup(p);
if(tmp->realm == NULL){
r->next = tmp->next;
free(tmp);
return krb5_enomem(context);
}
}
}else if(strncmp(from, to, strlen(to)) == 0){
p = from + strlen(from);
while(1){
while(p >= from && *p != '/') p--;
if(p == from)
return KRB5KDC_ERR_POLICY;
if(strncmp(to, from, p - from) == 0)
break;
tmp = calloc(1, sizeof(*tmp));
if(tmp == NULL)
return krb5_enomem(context);
tmp->next = r->next;
r->next = tmp;
tmp->realm = malloc(p - from + 1);
if(tmp->realm == NULL){
r->next = tmp->next;
free(tmp);
return krb5_enomem(context);
}
memcpy(tmp->realm, from, p - from);
tmp->realm[p - from] = '\0';
p--;
}
} else {
krb5_clear_error_message (context);
return KRB5KDC_ERR_POLICY;
}
return 0;
}
static int
make_paths(krb5_context context,
struct tr_realm *realms, const char *client_realm,
const char *server_realm)
{
struct tr_realm *r;
int ret;
const char *prev_realm = client_realm;
const char *next_realm = NULL;
for(r = realms; r; r = r->next){
/* it *might* be that you can have more than one empty
component in a row, at least that's how I interpret the
"," exception in 1510 */
if(r->realm[0] == '\0'){
while(r->next && r->next->realm[0] == '\0')
r = r->next;
if(r->next)
next_realm = r->next->realm;
else
next_realm = server_realm;
ret = make_path(context, r, prev_realm, next_realm);
if(ret){
free_realms(realms);
return ret;
}
}
prev_realm = r->realm;
}
return 0;
}
static int
expand_realms(krb5_context context,
struct tr_realm *realms, const char *client_realm)
{
struct tr_realm *r;
const char *prev_realm = NULL;
for(r = realms; r; r = r->next){
if(r->trailing_dot){
char *tmp;
size_t len;
if(prev_realm == NULL)
prev_realm = client_realm;
len = strlen(r->realm) + strlen(prev_realm) + 1;
tmp = realloc(r->realm, len);
if(tmp == NULL){
free_realms(realms);
return krb5_enomem(context);
}
r->realm = tmp;
strlcat(r->realm, prev_realm, len);
}else if(r->leading_slash && !r->leading_space && prev_realm){
/* yet another exception: if you use x500-names, the
leading realm doesn't have to be "quoted" with a space */
char *tmp;
size_t len = strlen(r->realm) + strlen(prev_realm) + 1;
tmp = malloc(len);
if(tmp == NULL){
free_realms(realms);
return krb5_enomem(context);
}
strlcpy(tmp, prev_realm, len);
strlcat(tmp, r->realm, len);
free(r->realm);
r->realm = tmp;
}
prev_realm = r->realm;
}
return 0;
}
static struct tr_realm *
make_realm(char *realm)
{
struct tr_realm *r;
char *p, *q;
int quote = 0;
r = calloc(1, sizeof(*r));
if(r == NULL){
free(realm);
return NULL;
}
r->realm = realm;
for(p = q = r->realm; *p; p++){
if(p == r->realm && *p == ' '){
r->leading_space = 1;
continue;
}
if(q == r->realm && *p == '/')
r->leading_slash = 1;
if(quote){
*q++ = *p;
quote = 0;
continue;
}
if(*p == '\\'){
quote = 1;
continue;
}
if(p[0] == '.' && p[1] == '\0')
r->trailing_dot = 1;
*q++ = *p;
}
*q = '\0';
return r;
}
static struct tr_realm*
append_realm(struct tr_realm *head, struct tr_realm *r)
{
struct tr_realm *p;
if(head == NULL){
r->next = NULL;
return r;
}
p = head;
while(p->next) p = p->next;
p->next = r;
return head;
}
static int
decode_realms(krb5_context context,
const char *tr, int length, struct tr_realm **realms)
{
struct tr_realm *r = NULL;
char *tmp;
int quote = 0;
const char *start = tr;
int i;
for(i = 0; i < length; i++){
if(quote){
quote = 0;
continue;
}
if(tr[i] == '\\'){
quote = 1;
continue;
}
if(tr[i] == ','){
tmp = malloc(tr + i - start + 1);
if(tmp == NULL) {
free_realms(*realms);
*realms = NULL;
return krb5_enomem(context);
}
memcpy(tmp, start, tr + i - start);
tmp[tr + i - start] = '\0';
r = make_realm(tmp);
if(r == NULL){
free_realms(*realms);
*realms = NULL;
return krb5_enomem(context);
}
*realms = append_realm(*realms, r);
start = tr + i + 1;
}
}
tmp = malloc(tr + i - start + 1);
if(tmp == NULL){
free_realms(*realms);
*realms = NULL;
return krb5_enomem(context);
}
memcpy(tmp, start, tr + i - start);
tmp[tr + i - start] = '\0';
r = make_realm(tmp);
if(r == NULL){
free_realms(*realms);
*realms = NULL;
return krb5_enomem(context);
}
*realms = append_realm(*realms, r);
return 0;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_domain_x500_decode(krb5_context context,
krb5_data tr, char ***realms, unsigned int *num_realms,
const char *client_realm, const char *server_realm)
{
struct tr_realm *r = NULL;
struct tr_realm *p, **q;
int ret;
if(tr.length == 0) {
*realms = NULL;
*num_realms = 0;
return 0;
}
/* split string in components */
ret = decode_realms(context, tr.data, tr.length, &r);
if(ret)
return ret;
/* apply prefix rule */
ret = expand_realms(context, r, client_realm);
if(ret)
return ret;
ret = make_paths(context, r, client_realm, server_realm);
if(ret)
return ret;
/* remove empty components and count realms */
*num_realms = 0;
for(q = &r; *q; ){
if((*q)->realm[0] == '\0'){
p = *q;
*q = (*q)->next;
free(p->realm);
free(p);
}else{
q = &(*q)->next;
(*num_realms)++;
}
}
if (*num_realms + 1 > UINT_MAX/sizeof(**realms))
return ERANGE;
{
char **R;
R = malloc((*num_realms + 1) * sizeof(*R));
*realms = R;
while(r){
*R++ = r->realm;
p = r->next;
free(r);
r = p;
}
if (*realms == NULL)
return krb5_enomem(context);
}
return 0;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_domain_x500_encode(char **realms, unsigned int num_realms,
krb5_data *encoding)
{
char *s = NULL;
int len = 0;
unsigned int i;
krb5_data_zero(encoding);
if (num_realms == 0)
return 0;
for(i = 0; i < num_realms; i++){
len += strlen(realms[i]);
if(realms[i][0] == '/')
len++;
}
len += num_realms - 1;
s = malloc(len + 1);
if (s == NULL)
return ENOMEM;
*s = '\0';
for(i = 0; i < num_realms; i++){
if(i)
strlcat(s, ",", len + 1);
if(realms[i][0] == '/')
strlcat(s, " ", len + 1);
strlcat(s, realms[i], len + 1);
}
encoding->data = s;
encoding->length = strlen(s);
return 0;
}
KRB5_LIB_FUNCTION void KRB5_LIB_CALL
_krb5_free_capath(krb5_context context, char **capath)
{
char **s;
for (s = capath; s && *s; ++s)
free(*s);
free(capath);
}
struct hier_iter {
const char *local_realm;
const char *server_realm;
const char *lr; /* Pointer into tail of local realm */
const char *sr; /* Pointer into tail of server realm */
size_t llen; /* Length of local_realm */
size_t slen; /* Length of server_realm */
size_t len; /* Length of common suffix */
size_t num; /* Path element count */
};
/*
* Step up from local_realm to common suffix, or else down to server_realm.
*/
static const char *
hier_next(struct hier_iter *state)
{
const char *lr = state->lr;
const char *sr = state->sr;
const char *lsuffix = state->local_realm + state->llen - state->len;
const char *server_realm = state->server_realm;
if (lr != NULL) {
while (lr < lsuffix)
if (*lr++ == '.')
return state->lr = lr;
state->lr = NULL;
}
if (sr != NULL) {
while (--sr >= server_realm)
if (sr == server_realm || sr[-1] == '.')
return state->sr = sr;
state->sr = NULL;
}
return NULL;
}
static void
hier_init(struct hier_iter *state, const char *local_realm, const char *server_realm)
{
size_t llen;
size_t slen;
size_t len = 0;
const char *lr;
const char *sr;
state->local_realm = local_realm;
state->server_realm = server_realm;
state->llen = llen = strlen(local_realm);
state->slen = slen = strlen(server_realm);
state->len = 0;
state->num = 0;
if (slen == 0 || llen == 0)
return;
/* Find first difference from the back */
for (lr = local_realm + llen, sr = server_realm + slen;
lr != local_realm && sr != server_realm;
--lr, --sr) {
if (lr[-1] != sr[-1])
break;
if (lr[-1] == '.')
len = llen - (lr - local_realm);
}
/* Nothing in common? */
if (*lr == '\0')
return;
/* Everything in common? */
if (llen == slen && lr == local_realm)
return;
/* Is one realm is a suffix of the other? */
if ((llen < slen && lr == local_realm && sr[-1] == '.') ||
(llen > slen && sr == server_realm && lr[-1] == '.'))
len = llen - (lr - local_realm);
state->len = len;
/* `lr` starts at local realm and walks up the tree to common suffix */
state->lr = local_realm;
/* `sr` starts at common suffix in server realm and walks down the tree */
state->sr = server_realm + slen - len;
/* Count elements and reset */
while (hier_next(state) != NULL)
++state->num;
state->lr = local_realm;
state->sr = server_realm + slen - len;
}
/*
* Find a referral path from client_realm to server_realm via local_realm.
* Either via [capaths] or hierarchicaly.
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
_krb5_find_capath(krb5_context context,
const char *client_realm,
const char *local_realm,
const char *server_realm,
krb5_boolean use_hierarchical,
char ***rpath,
size_t *npath)
{
char **confpath;
char **capath;
struct hier_iter hier_state;
char **rp;
const char *r;
*rpath = NULL;
*npath = 0;
confpath = krb5_config_get_strings(context, NULL, "capaths",
client_realm, server_realm, NULL);
if (confpath == NULL)
confpath = krb5_config_get_strings(context, NULL, "capaths",
local_realm, server_realm, NULL);
/*
* With a [capaths] setting from the client to the server we look for our
* own realm in the list. If our own realm is not present, we return the
* full list. Otherwise, we return our realm's successors, or possibly
* NULL. Ignoring a [capaths] settings risks loops plus would violate
* explicit policy and the principle of least surpise.
*/
if (confpath != NULL) {
char **start = confpath;
size_t i;
size_t n;
for (rp = start; *rp; rp++)
if (strcmp(*rp, local_realm) == 0)
start = rp+1;
n = rp - start;
if (n == 0) {
krb5_config_free_strings(confpath);
return 0;
}
capath = calloc(n + 1, sizeof(*capath));
if (capath == NULL) {
krb5_config_free_strings(confpath);
return krb5_enomem(context);
}
for (i = 0, rp = start; *rp; rp++) {
if ((capath[i++] = strdup(*rp)) == NULL) {
_krb5_free_capath(context, capath);
krb5_config_free_strings(confpath);
return krb5_enomem(context);
}
}
krb5_config_free_strings(confpath);
capath[i] = NULL;
*rpath = capath;
*npath = n;
return 0;
}
/* The use_hierarchical flag makes hierarchical path lookup unconditional */
if (! use_hierarchical &&
! krb5_config_get_bool_default(context, NULL, TRUE, "libdefaults",
"allow_hierarchical_capaths", NULL))
return 0;
/*
* When validating transit paths, local_realm == client_realm. Otherwise,
* with hierarchical referrals, they may differ, and we may be building a
* path forward from our own realm!
*/
hier_init(&hier_state, local_realm, server_realm);
if (hier_state.num == 0)
return 0;
rp = capath = calloc(hier_state.num + 1, sizeof(*capath));
if (capath == NULL)
return krb5_enomem(context);
while ((r = hier_next(&hier_state)) != NULL) {
if ((*rp++ = strdup(r)) == NULL) {
_krb5_free_capath(context, capath);
return krb5_enomem(context);
}
}
*rp = NULL;
*rpath = capath;
*npath = hier_state.num;
return 0;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_check_transited(krb5_context context,
krb5_const_realm client_realm,
krb5_const_realm server_realm,
krb5_realm *realms,
unsigned int num_realms,
int *bad_realm)
{
krb5_error_code ret = 0;
char **capath = NULL;
size_t num_capath = 0;
size_t i = 0;
size_t j = 0;
/* In transit checks hierarchical capaths are optional */
ret = _krb5_find_capath(context, client_realm, client_realm, server_realm,
FALSE, &capath, &num_capath);
if (ret)
return ret;
for (i = 0; i < num_realms; i++) {
for (j = 0; j < num_capath && capath[j]; ++j) {
/* `capath[j]' can't be NULL, but compilers be dumb */
if (strcmp(realms[i], capath[j]) == 0)
break;
}
if (j == num_capath || !capath[j]) {
_krb5_free_capath(context, capath);
krb5_set_error_message (context, KRB5KRB_AP_ERR_ILL_CR_TKT,
N_("no transit allowed "
"through realm %s from %s to %s", ""),
realms[i], client_realm, server_realm);
if (bad_realm)
*bad_realm = i;
return KRB5KRB_AP_ERR_ILL_CR_TKT;
}
}
_krb5_free_capath(context, capath);
return 0;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_check_transited_realms(krb5_context context,
const char *const *realms,
unsigned int num_realms,
int *bad_realm)
{
size_t i;
int ret = 0;
char **bad_realms = krb5_config_get_strings(context, NULL,
"libdefaults",
"transited_realms_reject",
NULL);
if(bad_realms == NULL)
return 0;
for(i = 0; i < num_realms; i++) {
char **p;
for(p = bad_realms; *p; p++)
if(strcmp(*p, realms[i]) == 0) {
ret = KRB5KRB_AP_ERR_ILL_CR_TKT;
krb5_set_error_message (context, ret,
N_("no transit allowed "
"through realm %s", ""),
*p);
if(bad_realm)
*bad_realm = i;
break;
}
}
krb5_config_free_strings(bad_realms);
return ret;
}
#if 0
int
main(int argc, char **argv)
{
krb5_data x;
char **r;
int num, i;
x.data = argv[1];
x.length = strlen(x.data);
if(domain_expand(x, &r, &num, argv[2], argv[3]))
exit(1);
for(i = 0; i < num; i++)
printf("%s\n", r[i]);
return 0;
}
#endif