Files
heimdal/lib/gssapi/krb5/store_cred.c
Nicolas Williams 2709f28a1b Make gss_store_cred*() work
krb5_cc_cache_match() searches all ccache collections for a ccache that
has credentials for a given principal name.  This includes MEMORY
ccaches, which means it can find the same ccache as is referenced by a
GSS cred handle given to gss_store_cred(), which means that
gss_store_cred() can fail.

For now we work around this by including a private variant of
krb5_cc_cache_match() that only searches the default ccache, not all
collections.  Eventually we should ensure that krb5_cc_default() also
searches all collection-type (other than MEMORY) ccaches for a default
credential, then we can go back to using krb5_cc_cache_match() (though
we'll need to make sure that MEMORY is searched last or not at all).
2019-09-05 09:52:49 -05:00

255 lines
8.7 KiB
C

/*
* Copyright (c) 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 "gsskrb5_locl.h"
static int
same_princ(krb5_context context, krb5_ccache id1, krb5_ccache id2)
{
krb5_error_code ret;
krb5_principal p1 = NULL;
krb5_principal p2 = NULL;
int same = 0;
ret = krb5_cc_get_principal(context, id1, &p1);
if (ret == 0)
ret = krb5_cc_get_principal(context, id2, &p2);
if (ret == 0)
same = krb5_principal_compare(context, p1, p2);
krb5_free_principal(context, p1);
krb5_free_principal(context, p2);
return same;
}
/*
* Like krb5_cc_cache_match(), but only looking in the default collection.
*
* We need this to avoid looking for MEMORY ccaches, which risks matching the
* same credential that we're storing. We could make sure that MEMORY ccaches
* are searched for last in krb5_cc_cache_match(), then ignore any MEMORY
* ccaches we find there, but, if we might then store in a ccache that will not
* be found later as the default ccache, then it's not worth it.
*
* XXX In order to remove this, we'll first need to make sure that
* krb5_cc_default() searches all collections when KRB5CCNAME is not set,
* then we'll need to make sure that krb5_cc_cache_match() searches MEMORY
* ccaches last (or else introduce a new ccache type like MEMORY but which
* is never searched or searchable), then make sure that the caller below
* treat finding a MEMORY the same as not finding a ccache at all.
*/
static krb5_error_code
ccache_match(krb5_context context,
krb5_principal princ,
const char *cctype,
krb5_ccache *id)
{
krb5_cc_cache_cursor cursor = NULL;
krb5_error_code ret;
*id = NULL;
ret = krb5_cc_cache_get_first(context, cctype, &cursor);
if (ret)
return ret;
while (krb5_cc_cache_next(context, cursor, id) == 0) {
krb5_principal p = NULL;
ret = krb5_cc_get_principal(context, *id, &p);
if (ret == 0 &&
krb5_principal_compare(context, princ, p)) {
krb5_free_principal(context, p);
krb5_cc_cache_end_seq_get(context, cursor);
return 0;
}
if (*id)
krb5_cc_close(context, *id);
*id = NULL;
}
krb5_cc_cache_end_seq_get(context, cursor);
return KRB5_CC_END;
}
OM_uint32 GSSAPI_CALLCONV
_gsskrb5_store_cred_into(OM_uint32 *minor_status,
gss_const_cred_id_t input_cred_handle,
gss_cred_usage_t cred_usage,
const gss_OID desired_mech,
OM_uint32 overwrite_cred,
OM_uint32 default_cred,
gss_const_key_value_set_t cred_store,
gss_OID_set *elements_stored,
gss_cred_usage_t *cred_usage_stored)
{
krb5_context context;
krb5_error_code ret;
gsskrb5_cred input_cred;
krb5_ccache id = NULL;
time_t exp_current;
time_t exp_new;
const char *cs_ccache_name = NULL;
OM_uint32 major_status;
*minor_status = 0;
/* Sanity check inputs */
if (cred_usage != GSS_C_INITIATE) {
/* It'd be nice if we could also do accept, writing a keytab */
*minor_status = GSS_KRB5_S_G_BAD_USAGE;
return GSS_S_FAILURE;
}
if (desired_mech != GSS_C_NO_OID &&
gss_oid_equal(desired_mech, GSS_KRB5_MECHANISM) == 0)
return GSS_S_BAD_MECH;
if (input_cred_handle == GSS_C_NO_CREDENTIAL)
return GSS_S_CALL_INACCESSIBLE_READ;
input_cred = (gsskrb5_cred)input_cred_handle;
/* Sanity check the input_cred */
if (input_cred->usage != cred_usage && input_cred->usage != GSS_C_BOTH) {
*minor_status = GSS_KRB5_S_G_BAD_USAGE;
return GSS_S_NO_CRED;
}
if (input_cred->principal == NULL) {
*minor_status = GSS_KRB5_S_KG_TGT_MISSING;
return GSS_S_NO_CRED;
}
/* Extract the ccache name from the store if given */
if (cred_store != GSS_C_NO_CRED_STORE) {
major_status = __gsskrb5_cred_store_find(minor_status, cred_store,
"ccache", &cs_ccache_name);
if (major_status == GSS_S_COMPLETE && cs_ccache_name == NULL) {
*minor_status = GSS_KRB5_S_G_UNKNOWN_CRED_STORE_ELEMENT;
major_status = GSS_S_NO_CRED;
}
if (GSS_ERROR(major_status))
return major_status;
}
GSSAPI_KRB5_INIT (&context);
HEIMDAL_MUTEX_lock(&input_cred->cred_id_mutex);
/* More sanity checking of the input_cred (good to fail early) */
ret = krb5_cc_get_lifetime(context, input_cred->ccache, &exp_new);
if (ret) {
HEIMDAL_MUTEX_unlock(&input_cred->cred_id_mutex);
*minor_status = ret;
return GSS_S_NO_CRED;
}
if (cs_ccache_name) {
/*
* Not the default ccache.
*
* Therefore not a collection type cache.
*
* Therefore there's no question of switching the primary ccache.
*
* Therefore we reset default_cred.
*
* XXX Perhaps we should fail in this case if default_cred is true.
*/
default_cred = 0;
ret = krb5_cc_resolve(context, cs_ccache_name, &id);
} else {
const char *cctype = NULL;
/*
* Use the default ccache, and if it's a collection, switch it if
* default_cred is true.
*/
ret = krb5_cc_default(context, &id);
if (ret == 0) {
cctype = krb5_cc_get_type(context, id);
if (krb5_cc_support_switch(context, cctype)) {
/* The default ccache is a collection type */
krb5_cc_close(context, id);
id = NULL;
/* Find a matching ccache or create a new one */
ret = ccache_match(context, input_cred->principal,
cctype, &id);
if (ret || id == NULL) {
/* Since the ccache is new, just store unconditionally */
overwrite_cred = 1;
ret = krb5_cc_new_unique(context, cctype, NULL, &id);
}
}
}
}
if (ret || id == NULL) {
HEIMDAL_MUTEX_unlock(&input_cred->cred_id_mutex);
*minor_status = ret;
return ret == 0 ? GSS_S_NO_CRED : GSS_S_FAILURE;
}
/*
* If the new creds are for a different principal than we had before,
* overwrite.
*/
if (!overwrite_cred && !same_princ(context, id, input_cred->ccache))
overwrite_cred = 1;
if (!overwrite_cred) {
/*
* If current creds are for the same princ as we already had creds for,
* and the new creds live longer than the old, overwrite.
*/
ret = krb5_cc_get_lifetime(context, id, &exp_current);
if (ret != 0 || exp_new > exp_current)
overwrite_cred = 1;
}
if (!overwrite_cred) {
/* Nothing to do */
HEIMDAL_MUTEX_unlock(&input_cred->cred_id_mutex);
krb5_cc_close(context, id);
*minor_status = 0;
return GSS_S_DUPLICATE_ELEMENT;
}
ret = krb5_cc_initialize(context, id, input_cred->principal);
if (ret == 0)
ret = krb5_cc_copy_match_f(context, input_cred->ccache, id, NULL, NULL,
NULL);
if (ret == 0 && default_cred)
krb5_cc_switch(context, id);
(void) krb5_cc_close(context, id);
HEIMDAL_MUTEX_unlock(&input_cred->cred_id_mutex);
*minor_status = ret;
return ret ? GSS_S_FAILURE : GSS_S_COMPLETE;
}