linux/net/sunrpc/auth_gss/gss_rpc_upcall.c
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   1/*
   2 *  linux/net/sunrpc/gss_rpc_upcall.c
   3 *
   4 *  Copyright (C) 2012 Simo Sorce <simo@redhat.com>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21#include <linux/types.h>
  22#include <linux/un.h>
  23
  24#include <linux/sunrpc/svcauth.h>
  25#include "gss_rpc_upcall.h"
  26
  27#define GSSPROXY_SOCK_PATHNAME  "/var/run/gssproxy.sock"
  28
  29#define GSSPROXY_PROGRAM        (400112u)
  30#define GSSPROXY_VERS_1         (1u)
  31
  32/*
  33 * Encoding/Decoding functions
  34 */
  35
  36enum {
  37        GSSX_NULL = 0,  /* Unused */
  38        GSSX_INDICATE_MECHS = 1,
  39        GSSX_GET_CALL_CONTEXT = 2,
  40        GSSX_IMPORT_AND_CANON_NAME = 3,
  41        GSSX_EXPORT_CRED = 4,
  42        GSSX_IMPORT_CRED = 5,
  43        GSSX_ACQUIRE_CRED = 6,
  44        GSSX_STORE_CRED = 7,
  45        GSSX_INIT_SEC_CONTEXT = 8,
  46        GSSX_ACCEPT_SEC_CONTEXT = 9,
  47        GSSX_RELEASE_HANDLE = 10,
  48        GSSX_GET_MIC = 11,
  49        GSSX_VERIFY = 12,
  50        GSSX_WRAP = 13,
  51        GSSX_UNWRAP = 14,
  52        GSSX_WRAP_SIZE_LIMIT = 15,
  53};
  54
  55#define PROC(proc, name)                                \
  56[GSSX_##proc] = {                                       \
  57        .p_proc   = GSSX_##proc,                        \
  58        .p_encode = gssx_enc_##name,    \
  59        .p_decode = gssx_dec_##name,    \
  60        .p_arglen = GSSX_ARG_##name##_sz,               \
  61        .p_replen = GSSX_RES_##name##_sz,               \
  62        .p_statidx = GSSX_##proc,                       \
  63        .p_name   = #proc,                              \
  64}
  65
  66static const struct rpc_procinfo gssp_procedures[] = {
  67        PROC(INDICATE_MECHS, indicate_mechs),
  68        PROC(GET_CALL_CONTEXT, get_call_context),
  69        PROC(IMPORT_AND_CANON_NAME, import_and_canon_name),
  70        PROC(EXPORT_CRED, export_cred),
  71        PROC(IMPORT_CRED, import_cred),
  72        PROC(ACQUIRE_CRED, acquire_cred),
  73        PROC(STORE_CRED, store_cred),
  74        PROC(INIT_SEC_CONTEXT, init_sec_context),
  75        PROC(ACCEPT_SEC_CONTEXT, accept_sec_context),
  76        PROC(RELEASE_HANDLE, release_handle),
  77        PROC(GET_MIC, get_mic),
  78        PROC(VERIFY, verify),
  79        PROC(WRAP, wrap),
  80        PROC(UNWRAP, unwrap),
  81        PROC(WRAP_SIZE_LIMIT, wrap_size_limit),
  82};
  83
  84
  85
  86/*
  87 * Common transport functions
  88 */
  89
  90static const struct rpc_program gssp_program;
  91
  92static int gssp_rpc_create(struct net *net, struct rpc_clnt **_clnt)
  93{
  94        static const struct sockaddr_un gssp_localaddr = {
  95                .sun_family             = AF_LOCAL,
  96                .sun_path               = GSSPROXY_SOCK_PATHNAME,
  97        };
  98        struct rpc_create_args args = {
  99                .net            = net,
 100                .protocol       = XPRT_TRANSPORT_LOCAL,
 101                .address        = (struct sockaddr *)&gssp_localaddr,
 102                .addrsize       = sizeof(gssp_localaddr),
 103                .servername     = "localhost",
 104                .program        = &gssp_program,
 105                .version        = GSSPROXY_VERS_1,
 106                .authflavor     = RPC_AUTH_NULL,
 107                /*
 108                 * Note we want connection to be done in the caller's
 109                 * filesystem namespace.  We therefore turn off the idle
 110                 * timeout, which would result in reconnections being
 111                 * done without the correct namespace:
 112                 */
 113                .flags          = RPC_CLNT_CREATE_NOPING |
 114                                  RPC_CLNT_CREATE_NO_IDLE_TIMEOUT
 115        };
 116        struct rpc_clnt *clnt;
 117        int result = 0;
 118
 119        clnt = rpc_create(&args);
 120        if (IS_ERR(clnt)) {
 121                dprintk("RPC:       failed to create AF_LOCAL gssproxy "
 122                                "client (errno %ld).\n", PTR_ERR(clnt));
 123                result = PTR_ERR(clnt);
 124                *_clnt = NULL;
 125                goto out;
 126        }
 127
 128        dprintk("RPC:       created new gssp local client (gssp_local_clnt: "
 129                        "%p)\n", clnt);
 130        *_clnt = clnt;
 131
 132out:
 133        return result;
 134}
 135
 136void init_gssp_clnt(struct sunrpc_net *sn)
 137{
 138        mutex_init(&sn->gssp_lock);
 139        sn->gssp_clnt = NULL;
 140}
 141
 142int set_gssp_clnt(struct net *net)
 143{
 144        struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 145        struct rpc_clnt *clnt;
 146        int ret;
 147
 148        mutex_lock(&sn->gssp_lock);
 149        ret = gssp_rpc_create(net, &clnt);
 150        if (!ret) {
 151                if (sn->gssp_clnt)
 152                        rpc_shutdown_client(sn->gssp_clnt);
 153                sn->gssp_clnt = clnt;
 154        }
 155        mutex_unlock(&sn->gssp_lock);
 156        return ret;
 157}
 158
 159void clear_gssp_clnt(struct sunrpc_net *sn)
 160{
 161        mutex_lock(&sn->gssp_lock);
 162        if (sn->gssp_clnt) {
 163                rpc_shutdown_client(sn->gssp_clnt);
 164                sn->gssp_clnt = NULL;
 165        }
 166        mutex_unlock(&sn->gssp_lock);
 167}
 168
 169static struct rpc_clnt *get_gssp_clnt(struct sunrpc_net *sn)
 170{
 171        struct rpc_clnt *clnt;
 172
 173        mutex_lock(&sn->gssp_lock);
 174        clnt = sn->gssp_clnt;
 175        if (clnt)
 176                atomic_inc(&clnt->cl_count);
 177        mutex_unlock(&sn->gssp_lock);
 178        return clnt;
 179}
 180
 181static int gssp_call(struct net *net, struct rpc_message *msg)
 182{
 183        struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 184        struct rpc_clnt *clnt;
 185        int status;
 186
 187        clnt = get_gssp_clnt(sn);
 188        if (!clnt)
 189                return -EIO;
 190        status = rpc_call_sync(clnt, msg, 0);
 191        if (status < 0) {
 192                dprintk("gssp: rpc_call returned error %d\n", -status);
 193                switch (status) {
 194                case -EPROTONOSUPPORT:
 195                        status = -EINVAL;
 196                        break;
 197                case -ECONNREFUSED:
 198                case -ETIMEDOUT:
 199                case -ENOTCONN:
 200                        status = -EAGAIN;
 201                        break;
 202                case -ERESTARTSYS:
 203                        if (signalled ())
 204                                status = -EINTR;
 205                        break;
 206                default:
 207                        break;
 208                }
 209        }
 210        rpc_release_client(clnt);
 211        return status;
 212}
 213
 214static void gssp_free_receive_pages(struct gssx_arg_accept_sec_context *arg)
 215{
 216        int i;
 217
 218        for (i = 0; i < arg->npages && arg->pages[i]; i++)
 219                __free_page(arg->pages[i]);
 220
 221        kfree(arg->pages);
 222}
 223
 224static int gssp_alloc_receive_pages(struct gssx_arg_accept_sec_context *arg)
 225{
 226        arg->npages = DIV_ROUND_UP(NGROUPS_MAX * 4, PAGE_SIZE);
 227        arg->pages = kzalloc(arg->npages * sizeof(struct page *), GFP_KERNEL);
 228        /*
 229         * XXX: actual pages are allocated by xdr layer in
 230         * xdr_partial_copy_from_skb.
 231         */
 232        if (!arg->pages)
 233                return -ENOMEM;
 234        return 0;
 235}
 236
 237/*
 238 * Public functions
 239 */
 240
 241/* numbers somewhat arbitrary but large enough for current needs */
 242#define GSSX_MAX_OUT_HANDLE     128
 243#define GSSX_MAX_SRC_PRINC      256
 244#define GSSX_KMEMBUF (GSSX_max_output_handle_sz + \
 245                        GSSX_max_oid_sz + \
 246                        GSSX_max_princ_sz + \
 247                        sizeof(struct svc_cred))
 248
 249int gssp_accept_sec_context_upcall(struct net *net,
 250                                struct gssp_upcall_data *data)
 251{
 252        struct gssx_ctx ctxh = {
 253                .state = data->in_handle
 254        };
 255        struct gssx_arg_accept_sec_context arg = {
 256                .input_token = data->in_token,
 257        };
 258        struct gssx_ctx rctxh = {
 259                /*
 260                 * pass in the max length we expect for each of these
 261                 * buffers but let the xdr code kmalloc them:
 262                 */
 263                .exported_context_token.len = GSSX_max_output_handle_sz,
 264                .mech.len = GSS_OID_MAX_LEN,
 265                .src_name.display_name.len = GSSX_max_princ_sz
 266        };
 267        struct gssx_res_accept_sec_context res = {
 268                .context_handle = &rctxh,
 269                .output_token = &data->out_token
 270        };
 271        struct rpc_message msg = {
 272                .rpc_proc = &gssp_procedures[GSSX_ACCEPT_SEC_CONTEXT],
 273                .rpc_argp = &arg,
 274                .rpc_resp = &res,
 275                .rpc_cred = NULL, /* FIXME ? */
 276        };
 277        struct xdr_netobj client_name = { 0 , NULL };
 278        int ret;
 279
 280        if (data->in_handle.len != 0)
 281                arg.context_handle = &ctxh;
 282        res.output_token->len = GSSX_max_output_token_sz;
 283
 284        ret = gssp_alloc_receive_pages(&arg);
 285        if (ret)
 286                return ret;
 287
 288        /* use nfs/ for targ_name ? */
 289
 290        ret = gssp_call(net, &msg);
 291
 292        gssp_free_receive_pages(&arg);
 293
 294        /* we need to fetch all data even in case of error so
 295         * that we can free special strctures is they have been allocated */
 296        data->major_status = res.status.major_status;
 297        data->minor_status = res.status.minor_status;
 298        if (res.context_handle) {
 299                data->out_handle = rctxh.exported_context_token;
 300                data->mech_oid.len = rctxh.mech.len;
 301                if (rctxh.mech.data)
 302                        memcpy(data->mech_oid.data, rctxh.mech.data,
 303                                                data->mech_oid.len);
 304                client_name = rctxh.src_name.display_name;
 305        }
 306
 307        if (res.options.count == 1) {
 308                gssx_buffer *value = &res.options.data[0].value;
 309                /* Currently we only decode CREDS_VALUE, if we add
 310                 * anything else we'll have to loop and match on the
 311                 * option name */
 312                if (value->len == 1) {
 313                        /* steal group info from struct svc_cred */
 314                        data->creds = *(struct svc_cred *)value->data;
 315                        data->found_creds = 1;
 316                }
 317                /* whether we use it or not, free data */
 318                kfree(value->data);
 319        }
 320
 321        if (res.options.count != 0) {
 322                kfree(res.options.data);
 323        }
 324
 325        /* convert to GSS_NT_HOSTBASED_SERVICE form and set into creds */
 326        if (data->found_creds && client_name.data != NULL) {
 327                char *c;
 328
 329                data->creds.cr_raw_principal = kstrndup(client_name.data,
 330                                                client_name.len, GFP_KERNEL);
 331
 332                data->creds.cr_principal = kstrndup(client_name.data,
 333                                                client_name.len, GFP_KERNEL);
 334                if (data->creds.cr_principal) {
 335                        /* terminate and remove realm part */
 336                        c = strchr(data->creds.cr_principal, '@');
 337                        if (c) {
 338                                *c = '\0';
 339
 340                                /* change service-hostname delimiter */
 341                                c = strchr(data->creds.cr_principal, '/');
 342                                if (c) *c = '@';
 343                        }
 344                        if (!c) {
 345                                /* not a service principal */
 346                                kfree(data->creds.cr_principal);
 347                                data->creds.cr_principal = NULL;
 348                        }
 349                }
 350        }
 351        kfree(client_name.data);
 352
 353        return ret;
 354}
 355
 356void gssp_free_upcall_data(struct gssp_upcall_data *data)
 357{
 358        kfree(data->in_handle.data);
 359        kfree(data->out_handle.data);
 360        kfree(data->out_token.data);
 361        free_svc_cred(&data->creds);
 362}
 363
 364/*
 365 * Initialization stuff
 366 */
 367static unsigned int gssp_version1_counts[ARRAY_SIZE(gssp_procedures)];
 368static const struct rpc_version gssp_version1 = {
 369        .number         = GSSPROXY_VERS_1,
 370        .nrprocs        = ARRAY_SIZE(gssp_procedures),
 371        .procs          = gssp_procedures,
 372        .counts         = gssp_version1_counts,
 373};
 374
 375static const struct rpc_version *gssp_version[] = {
 376        NULL,
 377        &gssp_version1,
 378};
 379
 380static struct rpc_stat gssp_stats;
 381
 382static const struct rpc_program gssp_program = {
 383        .name           = "gssproxy",
 384        .number         = GSSPROXY_PROGRAM,
 385        .nrvers         = ARRAY_SIZE(gssp_version),
 386        .version        = gssp_version,
 387        .stats          = &gssp_stats,
 388};
 389