net/sunrpc/auth_gss/gss_rpc_upcall.c

   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
  36 enum {
  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
  66 static 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
  90 static const struct rpc_program gssp_program;
  91
  92 static 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
 132 out:
 133         return result;
 134 }
 135
 136 void init_gssp_clnt(struct sunrpc_net *sn)
 137 {
 138         mutex_init(&sn->gssp_lock);
 139         sn->gssp_clnt = NULL;
 140 }
 141
 142 int 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
 159 void 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
 169 static 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
 181 static 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
 214 static 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
 224 static 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 = kcalloc(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 static char *gssp_stringify(struct xdr_netobj *netobj)
 238 {
 239         return kstrndup(netobj->data, netobj->len, GFP_KERNEL);
 240 }
 241
 242 static void gssp_hostbased_service(char **principal)
 243 {
 244         char *c;
 245
 246         if (!*principal)
 247                 return;
 248
 249         /* terminate and remove realm part */
 250         c = strchr(*principal, '@');
 251         if (c) {
 252                 *c = '\0';
 253
 254                 /* change service-hostname delimiter */
 255                 c = strchr(*principal, '/');
 256                 if (c)
 257                         *c = '@';
 258         }
 259         if (!c) {
 260                 /* not a service principal */
 261                 kfree(*principal);
 262                 *principal = NULL;
 263         }
 264 }
 265
 266 /*
 267  * Public functions
 268  */
 269
 270 /* numbers somewhat arbitrary but large enough for current needs */
 271 #define GSSX_MAX_OUT_HANDLE     128
 272 #define GSSX_MAX_SRC_PRINC      256
 273 #define GSSX_KMEMBUF (GSSX_max_output_handle_sz + \
 274                         GSSX_max_oid_sz + \
 275                         GSSX_max_princ_sz + \
 276                         sizeof(struct svc_cred))
 277
 278 int gssp_accept_sec_context_upcall(struct net *net,
 279                                 struct gssp_upcall_data *data)
 280 {
 281         struct gssx_ctx ctxh = {
 282                 .state = data->in_handle
 283         };
 284         struct gssx_arg_accept_sec_context arg = {
 285                 .input_token = data->in_token,
 286         };
 287         struct gssx_ctx rctxh = {
 288                 /*
 289                  * pass in the max length we expect for each of these
 290                  * buffers but let the xdr code kmalloc them:
 291                  */
 292                 .exported_context_token.len = GSSX_max_output_handle_sz,
 293                 .mech.len = GSS_OID_MAX_LEN,
 294                 .targ_name.display_name.len = GSSX_max_princ_sz,
 295                 .src_name.display_name.len = GSSX_max_princ_sz
 296         };
 297         struct gssx_res_accept_sec_context res = {
 298                 .context_handle = &rctxh,
 299                 .output_token = &data->out_token
 300         };
 301         struct rpc_message msg = {
 302                 .rpc_proc = &gssp_procedures[GSSX_ACCEPT_SEC_CONTEXT],
 303                 .rpc_argp = &arg,
 304                 .rpc_resp = &res,
 305                 .rpc_cred = NULL, /* FIXME ? */
 306         };
 307         struct xdr_netobj client_name = { 0 , NULL };
 308         struct xdr_netobj target_name = { 0, NULL };
 309         int ret;
 310
 311         if (data->in_handle.len != 0)
 312                 arg.context_handle = &ctxh;
 313         res.output_token->len = GSSX_max_output_token_sz;
 314
 315         ret = gssp_alloc_receive_pages(&arg);
 316         if (ret)
 317                 return ret;
 318
 319         ret = gssp_call(net, &msg);
 320
 321         gssp_free_receive_pages(&arg);
 322
 323         /* we need to fetch all data even in case of error so
 324          * that we can free special strctures is they have been allocated */
 325         data->major_status = res.status.major_status;
 326         data->minor_status = res.status.minor_status;
 327         if (res.context_handle) {
 328                 data->out_handle = rctxh.exported_context_token;
 329                 data->mech_oid.len = rctxh.mech.len;
 330                 if (rctxh.mech.data) {
 331                         memcpy(data->mech_oid.data, rctxh.mech.data,
 332                                                 data->mech_oid.len);
 333                         kfree(rctxh.mech.data);
 334                 }
 335                 client_name = rctxh.src_name.display_name;
 336                 target_name = rctxh.targ_name.display_name;
 337         }
 338
 339         if (res.options.count == 1) {
 340                 gssx_buffer *value = &res.options.data[0].value;
 341                 /* Currently we only decode CREDS_VALUE, if we add
 342                  * anything else we'll have to loop and match on the
 343                  * option name */
 344                 if (value->len == 1) {
 345                         /* steal group info from struct svc_cred */
 346                         data->creds = *(struct svc_cred *)value->data;
 347                         data->found_creds = 1;
 348                 }
 349                 /* whether we use it or not, free data */
 350                 kfree(value->data);
 351         }
 352
 353         if (res.options.count != 0) {
 354                 kfree(res.options.data);
 355         }
 356
 357         /* convert to GSS_NT_HOSTBASED_SERVICE form and set into creds */
 358         if (data->found_creds) {
 359                 if (client_name.data) {
 360                         data->creds.cr_raw_principal =
 361                                         gssp_stringify(&client_name);
 362                         data->creds.cr_principal =
 363                                         gssp_stringify(&client_name);
 364                         gssp_hostbased_service(&data->creds.cr_principal);
 365                 }
 366                 if (target_name.data) {
 367                         data->creds.cr_targ_princ =
 368                                         gssp_stringify(&target_name);
 369                         gssp_hostbased_service(&data->creds.cr_targ_princ);
 370                 }
 371         }
 372         kfree(client_name.data);
 373         kfree(target_name.data);
 374
 375         return ret;
 376 }
 377
 378 void gssp_free_upcall_data(struct gssp_upcall_data *data)
 379 {
 380         kfree(data->in_handle.data);
 381         kfree(data->out_handle.data);
 382         kfree(data->out_token.data);
 383         free_svc_cred(&data->creds);
 384 }
 385
 386 /*
 387  * Initialization stuff
 388  */
 389 static unsigned int gssp_version1_counts[ARRAY_SIZE(gssp_procedures)];
 390 static const struct rpc_version gssp_version1 = {
 391         .number         = GSSPROXY_VERS_1,
 392         .nrprocs        = ARRAY_SIZE(gssp_procedures),
 393         .procs          = gssp_procedures,
 394         .counts         = gssp_version1_counts,
 395 };
 396
 397 static const struct rpc_version *gssp_version[] = {
 398         NULL,
 399         &gssp_version1,
 400 };
 401
 402 static struct rpc_stat gssp_stats;
 403
 404 static const struct rpc_program gssp_program = {
 405         .name           = "gssproxy",
 406         .number         = GSSPROXY_PROGRAM,
 407         .nrvers         = ARRAY_SIZE(gssp_version),
 408         .version        = gssp_version,
 409         .stats          = &gssp_stats,
 410 };