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 = (kxdreproc_t)gssx_enc_##name,       \
  59         .p_decode = (kxdrdproc_t)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 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
 222 static int gssp_alloc_receive_pages(struct gssx_arg_accept_sec_context *arg)
 223 {
 224         arg->npages = DIV_ROUND_UP(NGROUPS_MAX * 4, PAGE_SIZE);
 225         arg->pages = kzalloc(arg->npages * sizeof(struct page *), GFP_KERNEL);
 226         /*
 227          * XXX: actual pages are allocated by xdr layer in
 228          * xdr_partial_copy_from_skb.
 229          */
 230         if (!arg->pages)
 231                 return -ENOMEM;
 232         return 0;
 233 }
 234
 235 /*
 236  * Public functions
 237  */
 238
 239 /* numbers somewhat arbitrary but large enough for current needs */
 240 #define GSSX_MAX_OUT_HANDLE     128
 241 #define GSSX_MAX_SRC_PRINC      256
 242 #define GSSX_KMEMBUF (GSSX_max_output_handle_sz + \
 243                         GSSX_max_oid_sz + \
 244                         GSSX_max_princ_sz + \
 245                         sizeof(struct svc_cred))
 246
 247 int gssp_accept_sec_context_upcall(struct net *net,
 248                                 struct gssp_upcall_data *data)
 249 {
 250         struct gssx_ctx ctxh = {
 251                 .state = data->in_handle
 252         };
 253         struct gssx_arg_accept_sec_context arg = {
 254                 .input_token = data->in_token,
 255         };
 256         struct gssx_ctx rctxh = {
 257                 /*
 258                  * pass in the max length we expect for each of these
 259                  * buffers but let the xdr code kmalloc them:
 260                  */
 261                 .exported_context_token.len = GSSX_max_output_handle_sz,
 262                 .mech.len = GSS_OID_MAX_LEN,
 263                 .src_name.display_name.len = GSSX_max_princ_sz
 264         };
 265         struct gssx_res_accept_sec_context res = {
 266                 .context_handle = &rctxh,
 267                 .output_token = &data->out_token
 268         };
 269         struct rpc_message msg = {
 270                 .rpc_proc = &gssp_procedures[GSSX_ACCEPT_SEC_CONTEXT],
 271                 .rpc_argp = &arg,
 272                 .rpc_resp = &res,
 273                 .rpc_cred = NULL, /* FIXME ? */
 274         };
 275         struct xdr_netobj client_name = { 0 , NULL };
 276         int ret;
 277
 278         if (data->in_handle.len != 0)
 279                 arg.context_handle = &ctxh;
 280         res.output_token->len = GSSX_max_output_token_sz;
 281
 282         ret = gssp_alloc_receive_pages(&arg);
 283         if (ret)
 284                 return ret;
 285
 286         /* use nfs/ for targ_name ? */
 287
 288         ret = gssp_call(net, &msg);
 289
 290         gssp_free_receive_pages(&arg);
 291
 292         /* we need to fetch all data even in case of error so
 293          * that we can free special strctures is they have been allocated */
 294         data->major_status = res.status.major_status;
 295         data->minor_status = res.status.minor_status;
 296         if (res.context_handle) {
 297                 data->out_handle = rctxh.exported_context_token;
 298                 data->mech_oid.len = rctxh.mech.len;
 299                 memcpy(data->mech_oid.data, rctxh.mech.data,
 300                                                 data->mech_oid.len);
 301                 client_name = rctxh.src_name.display_name;
 302         }
 303
 304         if (res.options.count == 1) {
 305                 gssx_buffer *value = &res.options.data[0].value;
 306                 /* Currently we only decode CREDS_VALUE, if we add
 307                  * anything else we'll have to loop and match on the
 308                  * option name */
 309                 if (value->len == 1) {
 310                         /* steal group info from struct svc_cred */
 311                         data->creds = *(struct svc_cred *)value->data;
 312                         data->found_creds = 1;
 313                 }
 314                 /* whether we use it or not, free data */
 315                 kfree(value->data);
 316         }
 317
 318         if (res.options.count != 0) {
 319                 kfree(res.options.data);
 320         }
 321
 322         /* convert to GSS_NT_HOSTBASED_SERVICE form and set into creds */
 323         if (data->found_creds && client_name.data != NULL) {
 324                 char *c;
 325
 326                 data->creds.cr_principal = kstrndup(client_name.data,
 327                                                 client_name.len, GFP_KERNEL);
 328                 if (data->creds.cr_principal) {
 329                         /* terminate and remove realm part */
 330                         c = strchr(data->creds.cr_principal, '@');
 331                         if (c) {
 332                                 *c = '\0';
 333
 334                                 /* change service-hostname delimiter */
 335                                 c = strchr(data->creds.cr_principal, '/');
 336                                 if (c) *c = '@';
 337                         }
 338                         if (!c) {
 339                                 /* not a service principal */
 340                                 kfree(data->creds.cr_principal);
 341                                 data->creds.cr_principal = NULL;
 342                         }
 343                 }
 344         }
 345         kfree(client_name.data);
 346
 347         return ret;
 348 }
 349
 350 void gssp_free_upcall_data(struct gssp_upcall_data *data)
 351 {
 352         kfree(data->in_handle.data);
 353         kfree(data->out_handle.data);
 354         kfree(data->out_token.data);
 355         free_svc_cred(&data->creds);
 356 }
 357
 358 /*
 359  * Initialization stuff
 360  */
 361
 362 static const struct rpc_version gssp_version1 = {
 363         .number         = GSSPROXY_VERS_1,
 364         .nrprocs        = ARRAY_SIZE(gssp_procedures),
 365         .procs          = gssp_procedures,
 366 };
 367
 368 static const struct rpc_version *gssp_version[] = {
 369         NULL,
 370         &gssp_version1,
 371 };
 372
 373 static struct rpc_stat gssp_stats;
 374
 375 static const struct rpc_program gssp_program = {
 376         .name           = "gssproxy",
 377         .number         = GSSPROXY_PROGRAM,
 378         .nrvers         = ARRAY_SIZE(gssp_version),
 379         .version        = gssp_version,
 380         .stats          = &gssp_stats,
 381 };