diff options
Diffstat (limited to 'src/plugins/preauth/wpse/wpse_main.c')
| -rw-r--r-- | src/plugins/preauth/wpse/wpse_main.c | 374 |
1 files changed, 374 insertions, 0 deletions
diff --git a/src/plugins/preauth/wpse/wpse_main.c b/src/plugins/preauth/wpse/wpse_main.c new file mode 100644 index 000000000..e7d7b6d55 --- /dev/null +++ b/src/plugins/preauth/wpse/wpse_main.c @@ -0,0 +1,374 @@ +/* + * Copyright (C) 2006 Red Hat, 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: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * 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. + * * Neither the name of Red Hat, Inc., 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 COPYRIGHT HOLDERS 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 COPYRIGHT OWNER + * 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. + */ + +/* Worst. Preauthentication. Scheme. Ever. */ + +#ident "$Id$" + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#ifdef HAVE_ERRNO_H +#include <errno.h> +#endif +#ifdef HAVE_STRING_H +#include <string.h> +#endif + +#include <arpa/inet.h> +#include <stdio.h> + +#include <krb5/krb5.h> +#include <krb5/preauth_plugin.h> + +/* This is not a standardized value. It's defined here only to make it easier + * to change in this module. */ +#define KRB5_PADATA_WPSE_REQ 131 + +static int +client_get_flags(krb5_context kcontext, krb5_preauthtype pa_type) +{ + return PA_REAL; +} + +static krb5_error_code +client_init(krb5_context kcontext, void **ctx) +{ + int *pctx; + + pctx = malloc(sizeof(int)); + if (pctx == NULL) + return ENOMEM; + *pctx = 0; + *ctx = pctx; + return 0; +} + +static void +client_fini(krb5_context kcontext, void *ctx) +{ + int *pctx; + + pctx = ctx; + if (pctx) { +#ifdef DEBUG + fprintf(stderr, "wpse module called total of %d times\n", *pctx); +#endif + free(pctx); + } +} + +static krb5_error_code +client_process(krb5_context kcontext, + void *plugin_context, + void *request_context, + krb5_kdc_req *request, + krb5_data *encoded_request_body, + krb5_data *encoded_previous_request, + krb5_pa_data *pa_data, + krb5_prompter_fct prompter, + void *prompter_data, + preauth_get_as_key_proc gak_fct, + void *gak_data, + krb5_data *salt, krb5_data *s2kparams, + krb5_keyblock *as_key, + krb5_pa_data **out_pa_data) +{ + krb5_pa_data *send_pa; + krb5_int32 nnonce, enctype; + krb5_keyblock *kb; + krb5_error_code status; + int *pctx; + +#ifdef DEBUG + fprintf(stderr, "%d bytes of preauthentication data (type %d)\n", + pa_data->length, pa_data->pa_type); +#endif + + pctx = plugin_context; + if (pctx) { + (*pctx)++; + } + + if (pa_data->length == 0) { + /* Create preauth data. */ + send_pa = malloc(sizeof(krb5_pa_data)); + if (send_pa == NULL) + return ENOMEM; + send_pa->pa_type = KRB5_PADATA_WPSE_REQ; + send_pa->length = 4; + send_pa->contents = malloc(4); + if (send_pa->contents == NULL) { + free(send_pa); + return ENOMEM; + } + /* Store the preauth data. */ + nnonce = htonl(request->nonce); + memcpy(send_pa->contents, &nnonce, 4); + *out_pa_data = send_pa; + } else { + /* A reply from the KDC. Conventionally this would be + * indicated by a different preauthentication type, but this + * mechanism/implementation doesn't do that. */ + if (pa_data->length > 4) { + memcpy(&enctype, pa_data->contents, 4); + kb = NULL; + status = krb5_init_keyblock(kcontext, ntohl(enctype), + pa_data->length - 4, &kb); + if (status != 0) + return status; + memcpy(kb->contents, pa_data->contents + 4, pa_data->length - 4); +#ifdef DEBUG + fprintf(stderr, "Recovered key type=%d, length=%d.\n", + kb->enctype, kb->length); +#endif + status = krb5_copy_keyblock_contents(kcontext, kb, as_key); + krb5_free_keyblock(kcontext, kb); + return status; + } + return KRB5KRB_ERR_GENERIC; + } + return 0; +} + +#define WPSE_MAGIC 0x77707365 +typedef struct _wpse_req_ctx +{ + int magic; + int value; +} wpse_req_ctx; + +static void +client_req_init(krb5_context kcontext, void *plugin_context, void **req_context_p) +{ + wpse_req_ctx *ctx; + + *req_context_p = NULL; + + /* Allocate a request context. Useful for verifying that we do in fact + * do per-request cleanup. */ + ctx = (wpse_req_ctx *) malloc(sizeof(*ctx)); + if (ctx == NULL) + return; + ctx->magic = WPSE_MAGIC; + ctx->value = 0xc0dec0de; + + *req_context_p = ctx; +} + +static void +client_req_cleanup(krb5_context kcontext, void *plugin_context, void *req_context) +{ + wpse_req_ctx *ctx = (wpse_req_ctx *)req_context; + + if (ctx) { +#ifdef DEBUG + fprintf(stderr, "client_req_cleanup: req_ctx at %p has magic %x and value %x\n", + ctx, ctx->magic, ctx->value); +#endif + if (ctx->magic != WPSE_MAGIC) { +#ifdef DEBUG + fprintf(stderr, "client_req_cleanup: req_context at %p has bad magic value %x\n", + ctx, ctx->magic); +#endif + return; + } + free(ctx); + } + return; +} + +/* Free state. */ +static krb5_error_code +server_free_pa_request_context(krb5_context kcontext, void *plugin_context, + void **request_context) +{ + if (*request_context != NULL) { + free(*request_context); + *request_context = NULL; + } + return 0; +} + +/* Obtain and return any preauthentication data (which is destined for the + * client) which matches type data->pa_type. */ +static krb5_error_code +server_get_edata(krb5_context kcontext, + krb5_kdc_req *request, + struct _krb5_db_entry_new *client, + struct _krb5_db_entry_new *server, + preauth_get_entry_data_proc server_get_entry_data, + void *pa_module_context, + krb5_pa_data *data) +{ + /* Return zero bytes of data. */ + data->length = 0; + data->contents = NULL; + return 0; +} + +/* Verify a request from a client. */ +static krb5_error_code +server_verify(krb5_context kcontext, + struct _krb5_db_entry_new *client, + krb5_data *req_pkt, + krb5_kdc_req *request, + krb5_enc_tkt_part *enc_tkt_reply, + krb5_pa_data *data, + preauth_get_entry_data_proc server_get_entry_data, + void *pa_module_context, + void **pa_request_context) +{ + krb5_int32 nnonce; + /* Verify the preauth data. */ + if (data->length != 4) + return KRB5KDC_ERR_PREAUTH_FAILED; + memcpy(&nnonce, data->contents, 4); + nnonce = ntohl(nnonce); + if (memcmp(&nnonce, &request->nonce, 4) != 0) + return KRB5KDC_ERR_PREAUTH_FAILED; + /* Note that preauthentication succeeded. */ + enc_tkt_reply->flags |= TKT_FLG_PRE_AUTH; + enc_tkt_reply->flags |= TKT_FLG_HW_AUTH; + /* Allocate a context. Useful for verifying that we do in fact do + * per-request cleanup. */ + if (*pa_request_context == NULL) + *pa_request_context = malloc(4); + return 0; +} + +/* Create the response for a client. */ +static krb5_error_code +server_return(krb5_context kcontext, + krb5_pa_data *padata, + struct _krb5_db_entry_new *client, + krb5_data *req_pkt, + krb5_kdc_req *request, + krb5_kdc_rep *reply, + struct _krb5_key_data *client_key, + krb5_keyblock *encrypting_key, + krb5_pa_data **send_pa, + preauth_get_entry_data_proc server_get_entry_data, + void *pa_module_context, + void **pa_request_context) +{ + /* This module does a couple of dumb things. It tags its reply with + * the same type as the initial challenge (expecting the client to sort + * out whether there's anything useful in there). Oh, and it replaces + * the AS reply key with one which is sent in the clear. */ + krb5_keyblock *kb; + krb5_int32 enctype; + int i; + + *send_pa = NULL; + + /* We'll want a key with the first supported enctype. */ + for (i = 0; i < request->nktypes; i++) { + kb = NULL; + if (krb5_init_keyblock(kcontext, request->ktype[i], 0, &kb) == 0) { + break; + } + } + if (i >= request->nktypes) { + /* No matching cipher type found. */ + return 0; + } + + /* Randomize a key and save it for the client. */ + if (krb5_c_make_random_key(kcontext, request->ktype[i], kb) != 0) { + krb5_free_keyblock(kcontext, kb); + return 0; + } +#ifdef DEBUG + fprintf(stderr, "Generated random key, type=%d, length=%d.\n", + kb->enctype, kb->length); +#endif + + *send_pa = malloc(sizeof(krb5_pa_data)); + if (*send_pa == NULL) { + krb5_free_keyblock(kcontext, kb); + return ENOMEM; + } + (*send_pa)->pa_type = KRB5_PADATA_WPSE_REQ; + (*send_pa)->length = 4 + kb->length; + (*send_pa)->contents = malloc(4 + kb->length); + if ((*send_pa)->contents == NULL) { + free(*send_pa); + *send_pa = NULL; + krb5_free_keyblock(kcontext, kb); + return ENOMEM; + } + + /* Store the preauth data. */ + enctype = htonl(kb->enctype); + memcpy((*send_pa)->contents, &enctype, 4); + memcpy((*send_pa)->contents + 4, kb->contents, kb->length); + krb5_copy_keyblock_contents(kcontext, kb, encrypting_key); + + /* Clean up. */ + krb5_free_keyblock(kcontext, kb); + + return 0; +} + +static int +server_get_flags(krb5_context kcontext, krb5_preauthtype pa_type) +{ + return PA_HARDWARE | PA_REPLACES_KEY; +} + +static krb5_preauthtype supported_client_pa_types[] = {KRB5_PADATA_WPSE_REQ, 0}; +static krb5_preauthtype supported_server_pa_types[] = {KRB5_PADATA_WPSE_REQ, 0}; + +struct krb5plugin_preauth_client_ftable_v0 preauthentication_client_0 = { + "wpse", /* name */ + &supported_client_pa_types[0], /* pa_type_list */ + NULL, /* enctype_list */ + client_init, /* plugin init function */ + client_fini, /* plugin fini function */ + client_get_flags, /* get flags function */ + client_req_init, /* request init function */ + client_req_cleanup, /* request fini function */ + client_process, /* process function */ + NULL, /* try_again function */ +}; + +struct krb5plugin_preauth_server_ftable_v0 preauthentication_server_0 = { + "wpse", + &supported_server_pa_types[0], + NULL, + NULL, + server_get_flags, + server_get_edata, + server_verify, + server_return, + server_free_pa_request_context, +}; |