net/sunrpc/auth_gss/gss_rpc_upcall.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *  linux/net/sunrpc/gss_rpc_upcall.c
   4  *
   5  *  Copyright (C) 2012 Simo Sorce <simo@redhat.com>
   6  */
   7
   8 #include <linux/types.h>
   9 #include <linux/un.h>
  10
  11 #include <linux/sunrpc/svcauth.h>
  12 #include "gss_rpc_upcall.h"
  13
  14 #define GSSPROXY_SOCK_PATHNAME  "/var/run/gssproxy.sock"
  15
  16 #define GSSPROXY_PROGRAM        (400112u)
  17 #define GSSPROXY_VERS_1         (1u)
  18
  19 /*
  20  * Encoding/Decoding functions
  21  */
  22
  23 enum {
  24         GSSX_NULL = 0,  /* Unused */
  25         GSSX_INDICATE_MECHS = 1,
  26         GSSX_GET_CALL_CONTEXT = 2,
  27         GSSX_IMPORT_AND_CANON_NAME = 3,
  28         GSSX_EXPORT_CRED = 4,
  29         GSSX_IMPORT_CRED = 5,
  30         GSSX_ACQUIRE_CRED = 6,
  31         GSSX_STORE_CRED = 7,
  32         GSSX_INIT_SEC_CONTEXT = 8,
  33         GSSX_ACCEPT_SEC_CONTEXT = 9,
  34         GSSX_RELEASE_HANDLE = 10,
  35         GSSX_GET_MIC = 11,
  36         GSSX_VERIFY = 12,
  37         GSSX_WRAP = 13,
  38         GSSX_UNWRAP = 14,
  39         GSSX_WRAP_SIZE_LIMIT = 15,
  40 };
  41
  42 #define PROC(proc, name)                                \
  43 [GSSX_##proc] = {                                       \
  44         .p_proc   = GSSX_##proc,                        \
  45         .p_encode = gssx_enc_##name,    \
  46         .p_decode = gssx_dec_##name,    \
  47         .p_arglen = GSSX_ARG_##name##_sz,               \
  48         .p_replen = GSSX_RES_##name##_sz,               \
  49         .p_statidx = GSSX_##proc,                       \
  50         .p_name   = #proc,                              \
  51 }
  52
  53 static const struct rpc_procinfo gssp_procedures[] = {
  54         PROC(INDICATE_MECHS, indicate_mechs),
  55         PROC(GET_CALL_CONTEXT, get_call_context),
  56         PROC(IMPORT_AND_CANON_NAME, import_and_canon_name),
  57         PROC(EXPORT_CRED, export_cred),
  58         PROC(IMPORT_CRED, import_cred),
  59         PROC(ACQUIRE_CRED, acquire_cred),
  60         PROC(STORE_CRED, store_cred),
  61         PROC(INIT_SEC_CONTEXT, init_sec_context),
  62         PROC(ACCEPT_SEC_CONTEXT, accept_sec_context),
  63         PROC(RELEASE_HANDLE, release_handle),
  64         PROC(GET_MIC, get_mic),
  65         PROC(VERIFY, verify),
  66         PROC(WRAP, wrap),
  67         PROC(UNWRAP, unwrap),
  68         PROC(WRAP_SIZE_LIMIT, wrap_size_limit),
  69 };
  70
  71
  72
  73 /*
  74  * Common transport functions
  75  */
  76
  77 static const struct rpc_program gssp_program;
  78
  79 static int gssp_rpc_create(struct net *net, struct rpc_clnt **_clnt)
  80 {
  81         static const struct sockaddr_un gssp_localaddr = {
  82                 .sun_family             = AF_LOCAL,
  83                 .sun_path               = GSSPROXY_SOCK_PATHNAME,
  84         };
  85         struct rpc_create_args args = {
  86                 .net            = net,
  87                 .protocol       = XPRT_TRANSPORT_LOCAL,
  88                 .address        = (struct sockaddr *)&gssp_localaddr,
  89                 .addrsize       = sizeof(gssp_localaddr),
  90                 .servername     = "localhost",
  91                 .program        = &gssp_program,
  92                 .version        = GSSPROXY_VERS_1,
  93                 .authflavor     = RPC_AUTH_NULL,
  94                 /*
  95                  * Note we want connection to be done in the caller's
  96                  * filesystem namespace.  We therefore turn off the idle
  97                  * timeout, which would result in reconnections being
  98                  * done without the correct namespace:
  99                  */
 100                 .flags          = RPC_CLNT_CREATE_NOPING |
 101                                   RPC_CLNT_CREATE_CONNECTED |
 102                                   RPC_CLNT_CREATE_NO_IDLE_TIMEOUT
 103         };
 104         struct rpc_clnt *clnt;
 105         int result = 0;
 106
 107         clnt = rpc_create(&args);
 108         if (IS_ERR(clnt)) {
 109                 dprintk("RPC:       failed to create AF_LOCAL gssproxy "
 110                                 "client (errno %ld).\n", PTR_ERR(clnt));
 111                 result = PTR_ERR(clnt);
 112                 *_clnt = NULL;
 113                 goto out;
 114         }
 115
 116         dprintk("RPC:       created new gssp local client (gssp_local_clnt: "
 117                         "%p)\n", clnt);
 118         *_clnt = clnt;
 119
 120 out:
 121         return result;
 122 }
 123
 124 void init_gssp_clnt(struct sunrpc_net *sn)
 125 {
 126         mutex_init(&sn->gssp_lock);
 127         sn->gssp_clnt = NULL;
 128 }
 129
 130 int set_gssp_clnt(struct net *net)
 131 {
 132         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 133         struct rpc_clnt *clnt;
 134         int ret;
 135
 136         mutex_lock(&sn->gssp_lock);
 137         ret = gssp_rpc_create(net, &clnt);
 138         if (!ret) {
 139                 if (sn->gssp_clnt)
 140                         rpc_shutdown_client(sn->gssp_clnt);
 141                 sn->gssp_clnt = clnt;
 142         }
 143         mutex_unlock(&sn->gssp_lock);
 144         return ret;
 145 }
 146
 147 void clear_gssp_clnt(struct sunrpc_net *sn)
 148 {
 149         mutex_lock(&sn->gssp_lock);
 150         if (sn->gssp_clnt) {
 151                 rpc_shutdown_client(sn->gssp_clnt);
 152                 sn->gssp_clnt = NULL;
 153         }
 154         mutex_unlock(&sn->gssp_lock);
 155 }
 156
 157 static struct rpc_clnt *get_gssp_clnt(struct sunrpc_net *sn)
 158 {
 159         struct rpc_clnt *clnt;
 160
 161         mutex_lock(&sn->gssp_lock);
 162         clnt = sn->gssp_clnt;
 163         if (clnt)
 164                 refcount_inc(&clnt->cl_count);
 165         mutex_unlock(&sn->gssp_lock);
 166         return clnt;
 167 }
 168
 169 static int gssp_call(struct net *net, struct rpc_message *msg)
 170 {
 171         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 172         struct rpc_clnt *clnt;
 173         int status;
 174
 175         clnt = get_gssp_clnt(sn);
 176         if (!clnt)
 177                 return -EIO;
 178         status = rpc_call_sync(clnt, msg, 0);
 179         if (status < 0) {
 180                 dprintk("gssp: rpc_call returned error %d\n", -status);
 181                 switch (status) {
 182                 case -EPROTONOSUPPORT:
 183                         status = -EINVAL;
 184                         break;
 185                 case -ECONNREFUSED:
 186                 case -ETIMEDOUT:
 187                 case -ENOTCONN:
 188                         status = -EAGAIN;
 189                         break;
 190                 case -ERESTARTSYS:
 191                         if (signalled ())
 192                                 status = -EINTR;
 193                         break;
 194                 default:
 195                         break;
 196                 }
 197         }
 198         rpc_release_client(clnt);
 199         return status;
 200 }
 201
 202 static void gssp_free_receive_pages(struct gssx_arg_accept_sec_context *arg)
 203 {
 204         unsigned int i;
 205
 206         for (i = 0; i < arg->npages && arg->pages[i]; i++)
 207                 __free_page(arg->pages[i]);
 208
 209         kfree(arg->pages);
 210 }
 211
 212 static int gssp_alloc_receive_pages(struct gssx_arg_accept_sec_context *arg)
 213 {
 214         unsigned int i;
 215
 216         arg->npages = DIV_ROUND_UP(NGROUPS_MAX * 4, PAGE_SIZE);
 217         arg->pages = kcalloc(arg->npages, sizeof(struct page *), GFP_KERNEL);
 218         if (!arg->pages)
 219                 return -ENOMEM;
 220         for (i = 0; i < arg->npages; i++) {
 221                 arg->pages[i] = alloc_page(GFP_KERNEL);
 222                 if (!arg->pages[i]) {
 223                         gssp_free_receive_pages(arg);
 224                         return -ENOMEM;
 225                 }
 226         }
 227         return 0;
 228 }
 229
 230 static char *gssp_stringify(struct xdr_netobj *netobj)
 231 {
 232         return kmemdup_nul(netobj->data, netobj->len, GFP_KERNEL);
 233 }
 234
 235 static void gssp_hostbased_service(char **principal)
 236 {
 237         char *c;
 238
 239         if (!*principal)
 240                 return;
 241
 242         /* terminate and remove realm part */
 243         c = strchr(*principal, '@');
 244         if (c) {
 245                 *c = '\0';
 246
 247                 /* change service-hostname delimiter */
 248                 c = strchr(*principal, '/');
 249                 if (c)
 250                         *c = '@';
 251         }
 252         if (!c) {
 253                 /* not a service principal */
 254                 kfree(*principal);
 255                 *principal = NULL;
 256         }
 257 }
 258
 259 /*
 260  * Public functions
 261  */
 262
 263 /* numbers somewhat arbitrary but large enough for current needs */
 264 #define GSSX_MAX_OUT_HANDLE     128
 265 #define GSSX_MAX_SRC_PRINC      256
 266 #define GSSX_KMEMBUF (GSSX_max_output_handle_sz + \
 267                         GSSX_max_oid_sz + \
 268                         GSSX_max_princ_sz + \
 269                         sizeof(struct svc_cred))
 270
 271 int gssp_accept_sec_context_upcall(struct net *net,
 272                                 struct gssp_upcall_data *data)
 273 {
 274         struct gssx_ctx ctxh = {
 275                 .state = data->in_handle
 276         };
 277         struct gssx_arg_accept_sec_context arg = {
 278                 .input_token = data->in_token,
 279         };
 280         struct gssx_ctx rctxh = {
 281                 /*
 282                  * pass in the max length we expect for each of these
 283                  * buffers but let the xdr code kmalloc them:
 284                  */
 285                 .exported_context_token.len = GSSX_max_output_handle_sz,
 286                 .mech.len = GSS_OID_MAX_LEN,
 287                 .targ_name.display_name.len = GSSX_max_princ_sz,
 288                 .src_name.display_name.len = GSSX_max_princ_sz
 289         };
 290         struct gssx_res_accept_sec_context res = {
 291                 .context_handle = &rctxh,
 292                 .output_token = &data->out_token
 293         };
 294         struct rpc_message msg = {
 295                 .rpc_proc = &gssp_procedures[GSSX_ACCEPT_SEC_CONTEXT],
 296                 .rpc_argp = &arg,
 297                 .rpc_resp = &res,
 298                 .rpc_cred = NULL, /* FIXME ? */
 299         };
 300         struct xdr_netobj client_name = { 0 , NULL };
 301         struct xdr_netobj target_name = { 0, NULL };
 302         int ret;
 303
 304         if (data->in_handle.len != 0)
 305                 arg.context_handle = &ctxh;
 306         res.output_token->len = GSSX_max_output_token_sz;
 307
 308         ret = gssp_alloc_receive_pages(&arg);
 309         if (ret)
 310                 return ret;
 311
 312         ret = gssp_call(net, &msg);
 313
 314         gssp_free_receive_pages(&arg);
 315
 316         /* we need to fetch all data even in case of error so
 317          * that we can free special strctures is they have been allocated */
 318         data->major_status = res.status.major_status;
 319         data->minor_status = res.status.minor_status;
 320         if (res.context_handle) {
 321                 data->out_handle = rctxh.exported_context_token;
 322                 data->mech_oid.len = rctxh.mech.len;
 323                 if (rctxh.mech.data) {
 324                         memcpy(data->mech_oid.data, rctxh.mech.data,
 325                                                 data->mech_oid.len);
 326                         kfree(rctxh.mech.data);
 327                 }
 328                 client_name = rctxh.src_name.display_name;
 329                 target_name = rctxh.targ_name.display_name;
 330         }
 331
 332         if (res.options.count == 1) {
 333                 gssx_buffer *value = &res.options.data[0].value;
 334                 /* Currently we only decode CREDS_VALUE, if we add
 335                  * anything else we'll have to loop and match on the
 336                  * option name */
 337                 if (value->len == 1) {
 338                         /* steal group info from struct svc_cred */
 339                         data->creds = *(struct svc_cred *)value->data;
 340                         data->found_creds = 1;
 341                 }
 342                 /* whether we use it or not, free data */
 343                 kfree(value->data);
 344         }
 345
 346         if (res.options.count != 0) {
 347                 kfree(res.options.data);
 348         }
 349
 350         /* convert to GSS_NT_HOSTBASED_SERVICE form and set into creds */
 351         if (data->found_creds) {
 352                 if (client_name.data) {
 353                         data->creds.cr_raw_principal =
 354                                         gssp_stringify(&client_name);
 355                         data->creds.cr_principal =
 356                                         gssp_stringify(&client_name);
 357                         gssp_hostbased_service(&data->creds.cr_principal);
 358                 }
 359                 if (target_name.data) {
 360                         data->creds.cr_targ_princ =
 361                                         gssp_stringify(&target_name);
 362                         gssp_hostbased_service(&data->creds.cr_targ_princ);
 363                 }
 364         }
 365         kfree(client_name.data);
 366         kfree(target_name.data);
 367
 368         return ret;
 369 }
 370
 371 void gssp_free_upcall_data(struct gssp_upcall_data *data)
 372 {
 373         kfree(data->in_handle.data);
 374         kfree(data->out_handle.data);
 375         kfree(data->out_token.data);
 376         free_svc_cred(&data->creds);
 377 }
 378
 379 /*
 380  * Initialization stuff
 381  */
 382 static unsigned int gssp_version1_counts[ARRAY_SIZE(gssp_procedures)];
 383 static const struct rpc_version gssp_version1 = {
 384         .number         = GSSPROXY_VERS_1,
 385         .nrprocs        = ARRAY_SIZE(gssp_procedures),
 386         .procs          = gssp_procedures,
 387         .counts         = gssp_version1_counts,
 388 };
 389
 390 static const struct rpc_version *gssp_version[] = {
 391         NULL,
 392         &gssp_version1,
 393 };
 394
 395 static struct rpc_stat gssp_stats;
 396
 397 static const struct rpc_program gssp_program = {
 398         .name           = "gssproxy",
 399         .number         = GSSPROXY_PROGRAM,
 400         .nrvers         = ARRAY_SIZE(gssp_version),
 401         .version        = gssp_version,
 402         .stats          = &gssp_stats,
 403 };