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|
/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
* Copyright 1995, 2003, 2008, 2012 by the Massachusetts Institute of Technology. All
* Rights Reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*/
/*
* This file contains routines for establishing, verifying, and any other
* necessary functions, for utilizing the pre-authentication field of the
* kerberos kdc request, with various hardware/software verification devices.
*/
#include "k5-int.h"
#include "k5-json.h"
#include "osconf.h"
#include <krb5/clpreauth_plugin.h>
#include "int-proto.h"
#include "os-proto.h"
#include "fast.h"
#include "init_creds_ctx.h"
#if !defined(_WIN32)
#include <unistd.h>
#endif
typedef struct {
struct krb5_clpreauth_vtable_st vt;
krb5_clpreauth_moddata data;
} *clpreauth_handle;
struct krb5_preauth_context_st {
clpreauth_handle *handles;
};
struct krb5_preauth_req_context_st {
krb5_context orig_context;
krb5_preauthtype *failed;
krb5_clpreauth_modreq *modreqs;
};
/* Release the memory used by a list of handles. */
static void
free_handles(krb5_context context, clpreauth_handle *handles)
{
clpreauth_handle *hp, h;
if (handles == NULL)
return;
for (hp = handles; *hp != NULL; hp++) {
h = *hp;
if (h->vt.fini != NULL)
h->vt.fini(context, h->data);
free(h);
}
free(handles);
}
/* Return an index into handles which can process pa_type, or -1 if none is
* found found. */
static int
search_module_list(clpreauth_handle *handles, krb5_preauthtype pa_type)
{
clpreauth_handle h;
int i, j;
for (i = 0; handles[i] != NULL; i++) {
h = handles[i];
for (j = 0; h->vt.pa_type_list[j] != 0; j++) {
if (h->vt.pa_type_list[j] == pa_type)
return i;
}
}
return -1;
}
/* Find the handle which can process pa_type, or NULL if none is found. On
* success, set *modreq_out to the corresponding per-request module data. */
static clpreauth_handle
find_module(krb5_context context, krb5_init_creds_context ctx,
krb5_preauthtype pa_type, krb5_clpreauth_modreq *modreq_out)
{
krb5_preauth_context pctx = context->preauth_context;
krb5_preauth_req_context reqctx = ctx->preauth_reqctx;
int i;
*modreq_out = NULL;
if (pctx == NULL || reqctx == NULL)
return NULL;
i = search_module_list(pctx->handles, pa_type);
if (i == -1)
return NULL;
*modreq_out = reqctx->modreqs[i];
return pctx->handles[i];
}
/* Initialize the preauth state for a krb5 context. */
void
k5_init_preauth_context(krb5_context context)
{
krb5_plugin_initvt_fn *modules = NULL, *mod;
clpreauth_handle *list = NULL, h;
int i;
size_t count;
krb5_preauthtype *tp;
/* Only do this once for each krb5_context */
if (context->preauth_context != NULL)
return;
/* Auto-register built-in modules. */
k5_plugin_register_dyn(context, PLUGIN_INTERFACE_CLPREAUTH, "pkinit",
"preauth");
k5_plugin_register_dyn(context, PLUGIN_INTERFACE_CLPREAUTH, "spake",
"preauth");
k5_plugin_register(context, PLUGIN_INTERFACE_CLPREAUTH,
"encrypted_challenge",
clpreauth_encrypted_challenge_initvt);
k5_plugin_register(context, PLUGIN_INTERFACE_CLPREAUTH,
"encrypted_timestamp",
clpreauth_encrypted_timestamp_initvt);
k5_plugin_register(context, PLUGIN_INTERFACE_CLPREAUTH, "sam2",
clpreauth_sam2_initvt);
k5_plugin_register(context, PLUGIN_INTERFACE_CLPREAUTH, "otp",
clpreauth_otp_initvt);
/* Get all available clpreauth vtables. */
if (k5_plugin_load_all(context, PLUGIN_INTERFACE_CLPREAUTH, &modules))
return;
/* Allocate a large enough list of handles. */
for (count = 0; modules[count] != NULL; count++);
list = calloc(count + 1, sizeof(*list));
if (list == NULL)
goto cleanup;
/* Create a handle for each module we can successfully initialize. */
count = 0;
for (mod = modules; *mod != NULL; mod++) {
h = calloc(1, sizeof(*h));
if (h == NULL)
goto cleanup;
/* Initialize the handle vtable. */
if ((*mod)(context, 1, 1, (krb5_plugin_vtable)&h->vt) != 0) {
free(h);
continue;
}
/* Check for a preauth type conflict with an existing module. */
for (tp = h->vt.pa_type_list; *tp != 0; tp++) {
i = search_module_list(list, *tp);
if (i != -1) {
TRACE_PREAUTH_CONFLICT(context, h->vt.name, list[i]->vt.name,
*tp);
break;
}
}
if (*tp != 0)
continue;
/* Initialize the module data. */
h->data = NULL;
if (h->vt.init != NULL && h->vt.init(context, &h->data) != 0) {
free(h);
continue;
}
list[count++] = h;
list[count] = NULL;
}
list[count] = NULL;
/* Place the constructed preauth context into the krb5 context. */
context->preauth_context = malloc(sizeof(*context->preauth_context));
if (context->preauth_context == NULL)
goto cleanup;
context->preauth_context->handles = list;
list = NULL;
cleanup:
k5_plugin_free_modules(context, modules);
free_handles(context, list);
}
/* Add pa_type to the list of types which has previously failed. */
krb5_error_code
k5_preauth_note_failed(krb5_init_creds_context ctx, krb5_preauthtype pa_type)
{
krb5_preauth_req_context reqctx = ctx->preauth_reqctx;
krb5_preauthtype *newptr;
size_t i;
for (i = 0; reqctx->failed != NULL && reqctx->failed[i] != 0; i++);
newptr = realloc(reqctx->failed, (i + 2) * sizeof(*newptr));
if (newptr == NULL)
return ENOMEM;
reqctx->failed = newptr;
reqctx->failed[i] = pa_type;
reqctx->failed[i + 1] = 0;
return 0;
}
/* Free the per-krb5_context preauth_context. This means clearing any
* plugin-specific context which may have been created, and then
* freeing the context itself. */
void
k5_free_preauth_context(krb5_context context)
{
krb5_preauth_context pctx = context->preauth_context;
if (pctx == NULL)
return;
free_handles(context, pctx->handles);
free(pctx);
context->preauth_context = NULL;
}
/* Initialize the per-AS-REQ context. This means calling the client_req_init
* function to give the plugin a chance to allocate a per-request context. */
void
k5_preauth_request_context_init(krb5_context context,
krb5_init_creds_context ctx)
{
krb5_preauth_context pctx = context->preauth_context;
clpreauth_handle h;
krb5_preauth_req_context reqctx;
size_t count, i;
if (pctx == NULL) {
k5_init_preauth_context(context);
pctx = context->preauth_context;
if (pctx == NULL)
return;
}
reqctx = calloc(1, sizeof(*reqctx));
if (reqctx == NULL)
return;
reqctx->orig_context = context;
/* Create an array of per-request module data objects corresponding to the
* preauth context's array of handles. */
for (count = 0; pctx->handles[count] != NULL; count++);
reqctx->modreqs = calloc(count, sizeof(*reqctx->modreqs));
for (i = 0; i < count; i++) {
h = pctx->handles[i];
if (h->vt.request_init != NULL)
h->vt.request_init(context, h->data, &reqctx->modreqs[i]);
}
ctx->preauth_reqctx = reqctx;
}
/* Free the per-AS-REQ context. This means clearing any request-specific
* context which the plugin may have created. */
void
k5_preauth_request_context_fini(krb5_context context,
krb5_init_creds_context ctx)
{
krb5_preauth_context pctx = context->preauth_context;
krb5_preauth_req_context reqctx = ctx->preauth_reqctx;
size_t i;
clpreauth_handle h;
if (reqctx == NULL)
return;
if (reqctx->orig_context == context && pctx != NULL) {
for (i = 0; pctx->handles[i] != NULL; i++) {
h = pctx->handles[i];
if (reqctx->modreqs[i] != NULL && h->vt.request_fini != NULL)
h->vt.request_fini(context, h->data, reqctx->modreqs[i]);
}
} else {
TRACE_PREAUTH_WRONG_CONTEXT(context);
}
free(reqctx->modreqs);
free(reqctx->failed);
free(reqctx);
ctx->preauth_reqctx = NULL;
}
krb5_error_code
k5_preauth_check_context(krb5_context context, krb5_init_creds_context ctx)
{
krb5_preauth_req_context reqctx = ctx->preauth_reqctx;
if (reqctx != NULL && reqctx->orig_context != context) {
k5_setmsg(context, EINVAL,
_("krb5_init_creds calls must use same library context"));
return EINVAL;
}
return 0;
}
/* Return 1 if pa_type is a real preauthentication mechanism according to the
* module h. Return 0 if it is not. */
static int
clpreauth_is_real(krb5_context context, clpreauth_handle h,
krb5_preauthtype pa_type)
{
if (h->vt.flags == NULL)
return 1;
return (h->vt.flags(context, pa_type) & PA_REAL) != 0;
}
static krb5_error_code
clpreauth_prep_questions(krb5_context context, clpreauth_handle h,
krb5_clpreauth_modreq modreq,
krb5_get_init_creds_opt *opt,
krb5_clpreauth_callbacks cb, krb5_clpreauth_rock rock,
krb5_kdc_req *req, krb5_data *req_body,
krb5_data *prev_req, krb5_pa_data *pa_data)
{
if (h->vt.prep_questions == NULL)
return 0;
return h->vt.prep_questions(context, h->data, modreq, opt, cb, rock, req,
req_body, prev_req, pa_data);
}
static krb5_error_code
clpreauth_process(krb5_context context, clpreauth_handle h,
krb5_clpreauth_modreq modreq, krb5_get_init_creds_opt *opt,
krb5_clpreauth_callbacks cb, krb5_clpreauth_rock rock,
krb5_kdc_req *req, krb5_data *req_body, krb5_data *prev_req,
krb5_pa_data *pa_data, krb5_prompter_fct prompter,
void *prompter_data, krb5_pa_data ***pa_data_out)
{
return h->vt.process(context, h->data, modreq, opt, cb, rock, req,
req_body, prev_req, pa_data, prompter, prompter_data,
pa_data_out);
}
static krb5_error_code
clpreauth_tryagain(krb5_context context, clpreauth_handle h,
krb5_clpreauth_modreq modreq, krb5_get_init_creds_opt *opt,
krb5_clpreauth_callbacks cb, krb5_clpreauth_rock rock,
krb5_kdc_req *req, krb5_data *req_body, krb5_data *prev_req,
krb5_preauthtype pa_type, krb5_error *error,
krb5_pa_data **error_padata, krb5_prompter_fct prompter,
void *prompter_data, krb5_pa_data ***pa_data_out)
{
if (h->vt.tryagain == NULL)
return 0;
return h->vt.tryagain(context, h->data, modreq, opt, cb, rock, req,
req_body, prev_req, pa_type, error, error_padata,
prompter, prompter_data, pa_data_out);
}
static krb5_error_code
clpreauth_gic_opts(krb5_context context, clpreauth_handle h,
krb5_get_init_creds_opt *opt, const char *attr,
const char *value)
{
if (h->vt.gic_opts == NULL)
return 0;
return h->vt.gic_opts(context, h->data, opt, attr, value);
}
/* Add the named encryption type to the existing list of ktypes. */
static void
grow_ktypes(krb5_enctype **out_ktypes, int *out_nktypes, krb5_enctype ktype)
{
int i;
krb5_enctype *ktypes;
for (i = 0; i < *out_nktypes; i++) {
if ((*out_ktypes)[i] == ktype)
return;
}
ktypes = realloc(*out_ktypes, (*out_nktypes + 2) * sizeof(ktype));
if (ktypes != NULL) {
*out_ktypes = ktypes;
ktypes[(*out_nktypes)++] = ktype;
ktypes[*out_nktypes] = 0;
}
}
/* Add a list of new pa_data items to an existing list. */
static int
grow_pa_list(krb5_pa_data ***out_pa_list, int *out_pa_list_size,
krb5_pa_data **addition, int num_addition)
{
krb5_pa_data **pa_list;
int i;
/* Allocate space for new entries and a null terminator. */
pa_list = realloc(*out_pa_list, (*out_pa_list_size + num_addition + 1) *
sizeof(*pa_list));
if (pa_list == NULL)
return ENOMEM;
*out_pa_list = pa_list;
for (i = 0; i < num_addition; i++)
pa_list[(*out_pa_list_size)++] = addition[i];
pa_list[*out_pa_list_size] = NULL;
return 0;
}
static krb5_enctype
get_etype(krb5_context context, krb5_clpreauth_rock rock)
{
krb5_init_creds_context ctx = (krb5_init_creds_context)rock;
if (ctx->reply != NULL)
return ctx->reply->enc_part.enctype;
return ctx->etype;
}
static krb5_keyblock *
fast_armor(krb5_context context, krb5_clpreauth_rock rock)
{
return ((krb5_init_creds_context)rock)->fast_state->armor_key;
}
static krb5_error_code
get_as_key(krb5_context context, krb5_clpreauth_rock rock,
krb5_keyblock **keyblock)
{
krb5_init_creds_context ctx = (krb5_init_creds_context)rock;
krb5_error_code ret;
krb5_data *salt;
if (ctx->as_key.length == 0) {
salt = ctx->default_salt ? NULL : &ctx->salt;
ret = ctx->gak_fct(context, ctx->request->client, ctx->etype,
ctx->prompter, ctx->prompter_data, salt,
&ctx->s2kparams, &ctx->as_key, ctx->gak_data,
ctx->rctx.items);
if (ret)
return ret;
}
*keyblock = &ctx->as_key;
return 0;
}
static krb5_error_code
set_as_key(krb5_context context, krb5_clpreauth_rock rock,
const krb5_keyblock *keyblock)
{
krb5_init_creds_context ctx = (krb5_init_creds_context)rock;
krb5_free_keyblock_contents(context, &ctx->as_key);
return krb5_copy_keyblock_contents(context, keyblock, &ctx->as_key);
}
static krb5_error_code
get_preauth_time(krb5_context context, krb5_clpreauth_rock rock,
krb5_boolean allow_unauth_time, krb5_timestamp *time_out,
krb5_int32 *usec_out)
{
return k5_init_creds_current_time(context, (krb5_init_creds_context)rock,
allow_unauth_time, time_out, usec_out);
}
static krb5_error_code
responder_ask_question(krb5_context context, krb5_clpreauth_rock rock,
const char *question, const char *challenge)
{
krb5_init_creds_context ctx = (krb5_init_creds_context)rock;
/* Force plugins to use need_as_key(). */
if (strcmp(KRB5_RESPONDER_QUESTION_PASSWORD, question) == 0)
return EINVAL;
return k5_response_items_ask_question(ctx->rctx.items, question,
challenge);
}
static const char *
responder_get_answer(krb5_context context, krb5_clpreauth_rock rock,
const char *question)
{
krb5_init_creds_context ctx = (krb5_init_creds_context)rock;
/* Don't let plugins get the raw password. */
if (strcmp(KRB5_RESPONDER_QUESTION_PASSWORD, question) == 0)
return NULL;
return k5_response_items_get_answer(ctx->rctx.items, question);
}
static void
need_as_key(krb5_context context, krb5_clpreauth_rock rock)
{
krb5_init_creds_context ctx = (krb5_init_creds_context)rock;
/* Calling gac_fct() with NULL as_key indicates desire for the AS key. */
ctx->gak_fct(context, ctx->request->client, ctx->etype, NULL, NULL, NULL,
NULL, NULL, ctx->gak_data, ctx->rctx.items);
}
static const char *
get_cc_config(krb5_context context, krb5_clpreauth_rock rock, const char *key)
{
krb5_init_creds_context ctx = (krb5_init_creds_context)rock;
k5_json_value value;
if (ctx->cc_config_in == NULL)
return NULL;
value = k5_json_object_get(ctx->cc_config_in, key);
if (value == NULL)
return NULL;
if (k5_json_get_tid(value) != K5_JSON_TID_STRING)
return NULL;
return k5_json_string_utf8(value);
}
static krb5_error_code
set_cc_config(krb5_context context, krb5_clpreauth_rock rock,
const char *key, const char *data)
{
krb5_init_creds_context ctx = (krb5_init_creds_context)rock;
krb5_error_code ret;
k5_json_string str;
if (ctx->cc_config_out == NULL)
return ENOENT;
ret = k5_json_string_create(data, &str);
if (ret)
return ret;
ret = k5_json_object_set(ctx->cc_config_out, key, str);
k5_json_release(str);
return ret;
}
static void
disable_fallback(krb5_context context, krb5_clpreauth_rock rock)
{
((krb5_init_creds_context)rock)->fallback_disabled = TRUE;
}
static struct krb5_clpreauth_callbacks_st callbacks = {
3,
get_etype,
fast_armor,
get_as_key,
set_as_key,
get_preauth_time,
responder_ask_question,
responder_get_answer,
need_as_key,
get_cc_config,
set_cc_config,
disable_fallback
};
/* Tweak the request body, for now adding any enctypes which the module claims
* to add support for to the list, but in the future perhaps doing more
* involved things. */
void
k5_preauth_prepare_request(krb5_context context, krb5_get_init_creds_opt *opt,
krb5_kdc_req *req)
{
krb5_preauth_context pctx = context->preauth_context;
clpreauth_handle *hp, h;
krb5_enctype *ep;
if (pctx == NULL)
return;
/* Don't modify the enctype list if it's specified in the gic opts. */
if (opt != NULL && (opt->flags & KRB5_GET_INIT_CREDS_OPT_ETYPE_LIST))
return;
for (hp = pctx->handles; *hp != NULL; hp++) {
h = *hp;
if (h->vt.enctype_list == NULL)
continue;
for (ep = h->vt.enctype_list; *ep != ENCTYPE_NULL; ep++)
grow_ktypes(&req->ktype, &req->nktypes, *ep);
}
}
const char * const * KRB5_CALLCONV
krb5_responder_list_questions(krb5_context ctx, krb5_responder_context rctx)
{
return k5_response_items_list_questions(rctx->items);
}
const char * KRB5_CALLCONV
krb5_responder_get_challenge(krb5_context ctx, krb5_responder_context rctx,
const char *question)
{
if (rctx == NULL)
return NULL;
return k5_response_items_get_challenge(rctx->items, question);
}
krb5_error_code KRB5_CALLCONV
krb5_responder_set_answer(krb5_context ctx, krb5_responder_context rctx,
const char *question, const char *answer)
{
if (rctx == NULL)
return EINVAL;
return k5_response_items_set_answer(rctx->items, question, answer);
}
/* Return true if pa_type matches the specific preauth type allowed for this
* authentication, or if there is no specific allowed type. */
static inline krb5_boolean
pa_type_allowed(krb5_init_creds_context ctx, krb5_preauthtype pa_type)
{
return ctx->allowed_preauth_type == KRB5_PADATA_NONE ||
pa_type == ctx->allowed_preauth_type;
}
/* Return true if pa_type previously failed during this authentication. */
static krb5_boolean
previously_failed(krb5_init_creds_context ctx, krb5_preauthtype pa_type)
{
krb5_preauth_req_context reqctx = ctx->preauth_reqctx;
size_t i;
for (i = 0; reqctx->failed != NULL && reqctx->failed[i] != 0; i++) {
if (reqctx->failed[i] == pa_type)
return TRUE;
}
return FALSE;
}
/* Allow clpreauth modules to process in_pa_list and produce output padata. */
static krb5_error_code
process_pa_data(krb5_context context, krb5_init_creds_context ctx,
krb5_pa_data **in_pa_list, krb5_boolean must_preauth,
krb5_pa_data ***out_pa_list, int *out_pa_list_size,
krb5_preauthtype *out_type)
{
struct errinfo save = EMPTY_ERRINFO;
krb5_pa_data *pa, **pa_ptr, **mod_pa;
krb5_error_code ret = 0;
krb5_clpreauth_modreq modreq;
clpreauth_handle h;
int real, i;
/* Process all informational padata types, then the first real preauth type
* we succeed on. */
for (real = 0; real <= 1; real++) {
for (pa_ptr = in_pa_list; *pa_ptr != NULL; pa_ptr++) {
pa = *pa_ptr;
/* Restrict real mechanisms to the chosen one if we have one. */
if (real && !pa_type_allowed(ctx, pa->pa_type))
continue;
h = find_module(context, ctx, pa->pa_type, &modreq);
if (h == NULL)
continue;
/* Make sure this type is for the current pass. */
if (clpreauth_is_real(context, h, pa->pa_type) != real)
continue;
/* Don't try a real mechanism again after failure. */
if (real && previously_failed(ctx, pa->pa_type))
continue;
mod_pa = NULL;
ret = clpreauth_process(context, h, modreq, ctx->opt, &callbacks,
(krb5_clpreauth_rock)ctx, ctx->request,
ctx->inner_request_body,
ctx->encoded_previous_request, pa,
ctx->prompter, ctx->prompter_data,
&mod_pa);
TRACE_PREAUTH_PROCESS(context, h->vt.name, pa->pa_type, real,
ret);
if (mod_pa != NULL) {
for (i = 0; mod_pa[i] != NULL; i++);
ret = grow_pa_list(out_pa_list, out_pa_list_size, mod_pa, i);
if (ret) {
krb5_free_pa_data(context, mod_pa);
goto cleanup;
}
free(mod_pa);
}
/* Don't continue to try mechanisms after a keyboard interrupt. */
if (ret == KRB5_LIBOS_PWDINTR)
goto cleanup;
if (ret == 0 && real) {
/* Stop now and record which real padata type we answered. */
*out_type = pa->pa_type;
goto cleanup;
} else if (real && save.code == 0) {
/* Save the first error we get from a real preauth type. */
k5_save_ctx_error(context, ret, &save);
}
if (real && ret) {
/* Don't try this mechanism again for this authentication. */
ret = k5_preauth_note_failed(ctx, pa->pa_type);
if (ret)
goto cleanup;
}
}
}
if (must_preauth) {
/* No real preauth types succeeded and we needed to preauthenticate. */
if (save.code != 0) {
ret = k5_restore_ctx_error(context, &save);
k5_wrapmsg(context, ret, KRB5_PREAUTH_FAILED,
_("Pre-authentication failed"));
}
ret = KRB5_PREAUTH_FAILED;
}
cleanup:
k5_clear_error(&save);
return ret;
}
static inline krb5_data
padata2data(krb5_pa_data p)
{
krb5_data d;
d.magic = KV5M_DATA;
d.length = p.length;
d.data = (char *) p.contents;
return d;
}
/* Set salt in rock based on pw-salt or afs3-salt elements in padata. */
static krb5_error_code
get_salt(krb5_context context, krb5_init_creds_context ctx,
krb5_pa_data **padata)
{
krb5_error_code ret;
krb5_pa_data *pa;
krb5_data d;
const char *p;
/* Look for a pw-salt or afs3-salt element. */
pa = krb5int_find_pa_data(context, padata, KRB5_PADATA_PW_SALT);
if (pa == NULL)
pa = krb5int_find_pa_data(context, padata, KRB5_PADATA_AFS3_SALT);
if (pa == NULL)
return 0;
/* Set ctx->salt based on the element we found. */
krb5_free_data_contents(context, &ctx->salt);
d = padata2data(*pa);
ret = krb5int_copy_data_contents(context, &d, &ctx->salt);
if (ret)
return ret;
/* Adjust the salt if we got it from an afs3-salt element. */
if (pa->pa_type == KRB5_PADATA_AFS3_SALT) {
/* Work around a (possible) old Heimdal KDC foible. */
p = memchr(ctx->salt.data, '@', ctx->salt.length);
if (p != NULL)
ctx->salt.length = p - ctx->salt.data;
/* Tolerate extra null in MIT KDC afs3-salt value. */
if (ctx->salt.length > 0 &&
ctx->salt.data[ctx->salt.length - 1] == '\0')
ctx->salt.length--;
/* Set an s2kparams value to indicate AFS string-to-key. */
krb5_free_data_contents(context, &ctx->s2kparams);
ret = alloc_data(&ctx->s2kparams, 1);
if (ret)
return ret;
ctx->s2kparams.data[0] = '\1';
}
ctx->default_salt = FALSE;
TRACE_PREAUTH_SALT(context, &ctx->salt, pa->pa_type);
return 0;
}
/* Set etype info parameters in rock based on padata. */
krb5_error_code
k5_get_etype_info(krb5_context context, krb5_init_creds_context ctx,
krb5_pa_data **padata)
{
krb5_error_code ret = 0;
krb5_pa_data *pa;
krb5_data d;
krb5_etype_info etype_info = NULL, e;
krb5_etype_info_entry *entry;
krb5_boolean valid_found;
int i;
/* Find an etype-info2 or etype-info element in padata. */
pa = krb5int_find_pa_data(context, padata, KRB5_PADATA_ETYPE_INFO2);
if (pa != NULL) {
d = padata2data(*pa);
(void)decode_krb5_etype_info2(&d, &etype_info);
} else {
pa = krb5int_find_pa_data(context, padata, KRB5_PADATA_ETYPE_INFO);
if (pa != NULL) {
d = padata2data(*pa);
(void)decode_krb5_etype_info(&d, &etype_info);
}
}
/* Fall back to pw-salt/afs3-salt if no etype-info element is present. */
if (etype_info == NULL)
return get_salt(context, ctx, padata);
/* Search entries in order of the request's enctype preference. */
entry = NULL;
valid_found = FALSE;
for (i = 0; i < ctx->request->nktypes && entry == NULL; i++) {
for (e = etype_info; *e != NULL && entry == NULL; e++) {
if ((*e)->etype == ctx->request->ktype[i])
entry = *e;
if (krb5_c_valid_enctype((*e)->etype))
valid_found = TRUE;
}
}
if (entry == NULL) {
ret = (valid_found) ? KRB5_CONFIG_ETYPE_NOSUPP :
KRB5_PROG_ETYPE_NOSUPP;
goto cleanup;
}
/* Set etype/salt/s2kparams fields based on the entry we selected. */
ctx->etype = entry->etype;
krb5_free_data_contents(context, &ctx->salt);
if (entry->length != KRB5_ETYPE_NO_SALT) {
ctx->salt = make_data(entry->salt, entry->length);
entry->salt = NULL;
ctx->default_salt = FALSE;
} else {
ctx->salt = empty_data();
ctx->default_salt = TRUE;
}
krb5_free_data_contents(context, &ctx->s2kparams);
ctx->s2kparams = entry->s2kparams;
entry->s2kparams = empty_data();
TRACE_PREAUTH_ETYPE_INFO(context, ctx->etype, &ctx->salt, &ctx->s2kparams);
cleanup:
krb5_free_etype_info(context, etype_info);
return ret;
}
/* Look for an fx-cookie element in in_padata and add it to out_pa_list. */
static krb5_error_code
copy_cookie(krb5_context context, krb5_pa_data **in_padata,
krb5_pa_data ***out_pa_list, int *out_pa_list_size)
{
krb5_error_code ret;
krb5_pa_data *cookie, *pa = NULL;
cookie = krb5int_find_pa_data(context, in_padata, KRB5_PADATA_FX_COOKIE);
if (cookie == NULL)
return 0;
TRACE_PREAUTH_COOKIE(context, cookie->length, cookie->contents);
pa = k5alloc(sizeof(*pa), &ret);
if (pa == NULL)
return ret;
*pa = *cookie;
pa->contents = k5memdup(cookie->contents, cookie->length, &ret);
if (pa->contents == NULL)
goto error;
ret = grow_pa_list(out_pa_list, out_pa_list_size, &pa, 1);
if (ret)
goto error;
return 0;
error:
free(pa->contents);
free(pa);
return ENOMEM;
}
/*
* If the module for pa_type can adjust its AS_REQ data using the contents of
* err and err_padata, return 0 with *padata_out set to a padata list for the
* next request. If it's the sort of correction which requires that we ask the
* user another question, we let the calling application deal with it.
*/
krb5_error_code
k5_preauth_tryagain(krb5_context context, krb5_init_creds_context ctx,
krb5_preauthtype pa_type, krb5_error *err,
krb5_pa_data **err_padata, krb5_pa_data ***padata_out)
{
krb5_error_code ret;
krb5_pa_data **mod_pa;
krb5_clpreauth_modreq modreq;
clpreauth_handle h;
int count;
*padata_out = NULL;
TRACE_PREAUTH_TRYAGAIN_INPUT(context, pa_type, err_padata);
h = find_module(context, ctx, pa_type, &modreq);
if (h == NULL)
return KRB5KRB_ERR_GENERIC;
mod_pa = NULL;
ret = clpreauth_tryagain(context, h, modreq, ctx->opt, &callbacks,
(krb5_clpreauth_rock)ctx, ctx->request,
ctx->inner_request_body,
ctx->encoded_previous_request, pa_type, err,
err_padata, ctx->prompter, ctx->prompter_data,
&mod_pa);
TRACE_PREAUTH_TRYAGAIN(context, h->vt.name, pa_type, ret);
if (!ret && mod_pa == NULL)
ret = KRB5KRB_ERR_GENERIC;
if (ret) {
k5_preauth_note_failed(ctx, pa_type);
return ret;
}
for (count = 0; mod_pa[count] != NULL; count++);
ret = copy_cookie(context, err_padata, &mod_pa, &count);
if (ret) {
krb5_free_pa_data(context, mod_pa);
return ret;
}
TRACE_PREAUTH_TRYAGAIN_OUTPUT(context, mod_pa);
*padata_out = mod_pa;
return 0;
}
/* Compile the set of response items for in_padata by invoke each module's
* prep_questions method. */
static krb5_error_code
fill_response_items(krb5_context context, krb5_init_creds_context ctx,
krb5_pa_data **in_padata)
{
krb5_error_code ret;
krb5_pa_data *pa;
krb5_clpreauth_modreq modreq;
clpreauth_handle h;
int i;
k5_response_items_reset(ctx->rctx.items);
for (i = 0; in_padata[i] != NULL; i++) {
pa = in_padata[i];
if (!pa_type_allowed(ctx, pa->pa_type))
continue;
h = find_module(context, ctx, pa->pa_type, &modreq);
if (h == NULL)
continue;
ret = clpreauth_prep_questions(context, h, modreq, ctx->opt,
&callbacks, (krb5_clpreauth_rock)ctx,
ctx->request, ctx->inner_request_body,
ctx->encoded_previous_request, pa);
if (ret)
return ret;
}
return 0;
}
krb5_error_code
k5_preauth(krb5_context context, krb5_init_creds_context ctx,
krb5_pa_data **in_padata, krb5_boolean must_preauth,
krb5_pa_data ***padata_out, krb5_preauthtype *pa_type_out)
{
int out_pa_list_size = 0;
krb5_pa_data **out_pa_list = NULL;
krb5_error_code ret;
krb5_responder_fn responder;
void *responder_data;
*padata_out = NULL;
*pa_type_out = KRB5_PADATA_NONE;
/* We should never invoke preauth modules when identifying the realm. */
if (in_padata == NULL || ctx->identify_realm)
return 0;
TRACE_PREAUTH_INPUT(context, in_padata);
/* Scan the padata list and process etype-info or salt elements. */
ret = k5_get_etype_info(context, ctx, in_padata);
if (ret)
return ret;
/* Copy the cookie if there is one. */
ret = copy_cookie(context, in_padata, &out_pa_list, &out_pa_list_size);
if (ret)
goto error;
/* If we can't initialize the preauth context, stop with what we have. */
k5_init_preauth_context(context);
if (context->preauth_context == NULL) {
*padata_out = out_pa_list;
out_pa_list = NULL;
goto error;
}
/* Get a list of response items for in_padata from the preauth modules. */
ret = fill_response_items(context, ctx, in_padata);
if (ret)
goto error;
/* Call the responder to answer response items. */
k5_gic_opt_get_responder(ctx->opt, &responder, &responder_data);
if (responder != NULL && !k5_response_items_empty(ctx->rctx.items)) {
ret = (*responder)(context, responder_data, &ctx->rctx);
if (ret)
goto error;
}
ret = process_pa_data(context, ctx, in_padata, must_preauth,
&out_pa_list, &out_pa_list_size, pa_type_out);
if (ret)
goto error;
TRACE_PREAUTH_OUTPUT(context, out_pa_list);
*padata_out = out_pa_list;
return 0;
error:
krb5_free_pa_data(context, out_pa_list);
return ret;
}
/*
* Give all the preauth plugins a look at the preauth option which
* has just been set
*/
krb5_error_code
krb5_preauth_supply_preauth_data(krb5_context context,
krb5_get_init_creds_opt *opt,
const char *attr, const char *value)
{
krb5_preauth_context pctx = context->preauth_context;
clpreauth_handle *hp, h;
krb5_error_code ret;
if (pctx == NULL) {
k5_init_preauth_context(context);
pctx = context->preauth_context;
if (pctx == NULL) {
k5_setmsg(context, EINVAL,
_("Unable to initialize preauth context"));
return EINVAL;
}
}
/*
* Go down the list of preauth modules, and supply them with the
* attribute/value pair.
*/
for (hp = pctx->handles; *hp != NULL; hp++) {
h = *hp;
ret = clpreauth_gic_opts(context, h, opt, attr, value);
if (ret) {
k5_prependmsg(context, ret, _("Preauth module %s"), h->vt.name);
return ret;
}
}
return 0;
}
|