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_NO_IDLE_TIMEOUT
 102         };
 103         struct rpc_clnt *clnt;
 104         int result = 0;
 105
 106         clnt = rpc_create(&args);
 107         if (IS_ERR(clnt)) {
 108                 dprintk("RPC:       failed to create AF_LOCAL gssproxy "
 109                                 "client (errno %ld).\n", PTR_ERR(clnt));
 110                 result = PTR_ERR(clnt);
 111                 *_clnt = NULL;
 112                 goto out;
 113         }
 114
 115         dprintk("RPC:       created new gssp local client (gssp_local_clnt: "
 116                         "%p)\n", clnt);
 117         *_clnt = clnt;
 118
 119 out:
 120         return result;
 121 }
 122
 123 void init_gssp_clnt(struct sunrpc_net *sn)
 124 {
 125         mutex_init(&sn->gssp_lock);
 126         sn->gssp_clnt = NULL;
 127 }
 128
 129 int set_gssp_clnt(struct net *net)
 130 {
 131         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 132         struct rpc_clnt *clnt;
 133         int ret;
 134
 135         mutex_lock(&sn->gssp_lock);
 136         ret = gssp_rpc_create(net, &clnt);
 137         if (!ret) {
 138                 if (sn->gssp_clnt)
 139                         rpc_shutdown_client(sn->gssp_clnt);
 140                 sn->gssp_clnt = clnt;
 141         }
 142         mutex_unlock(&sn->gssp_lock);
 143         return ret;
 144 }
 145
 146 void clear_gssp_clnt(struct sunrpc_net *sn)
 147 {
 148         mutex_lock(&sn->gssp_lock);
 149         if (sn->gssp_clnt) {
 150                 rpc_shutdown_client(sn->gssp_clnt);
 151                 sn->gssp_clnt = NULL;
 152         }
 153         mutex_unlock(&sn->gssp_lock);
 154 }
 155
 156 static struct rpc_clnt *get_gssp_clnt(struct sunrpc_net *sn)
 157 {
 158         struct rpc_clnt *clnt;
 159
 160         mutex_lock(&sn->gssp_lock);
 161         clnt = sn->gssp_clnt;
 162         if (clnt)
 163                 atomic_inc(&clnt->cl_count);
 164         mutex_unlock(&sn->gssp_lock);
 165         return clnt;
 166 }
 167
 168 static int gssp_call(struct net *net, struct rpc_message *msg)
 169 {
 170         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 171         struct rpc_clnt *clnt;
 172         int status;
 173
 174         clnt = get_gssp_clnt(sn);
 175         if (!clnt)
 176                 return -EIO;
 177         status = rpc_call_sync(clnt, msg, 0);
 178         if (status < 0) {
 179                 dprintk("gssp: rpc_call returned error %d\n", -status);
 180                 switch (status) {
 181                 case -EPROTONOSUPPORT:
 182                         status = -EINVAL;
 183                         break;
 184                 case -ECONNREFUSED:
 185                 case -ETIMEDOUT:
 186                 case -ENOTCONN:
 187                         status = -EAGAIN;
 188                         break;
 189                 case -ERESTARTSYS:
 190                         if (signalled ())
 191                                 status = -EINTR;
 192                         break;
 193                 default:
 194                         break;
 195                 }
 196         }
 197         rpc_release_client(clnt);
 198         return status;
 199 }
 200
 201 static void gssp_free_receive_pages(struct gssx_arg_accept_sec_context *arg)
 202 {
 203         unsigned int i;
 204
 205         for (i = 0; i < arg->npages && arg->pages[i]; i++)
 206                 __free_page(arg->pages[i]);
 207
 208         kfree(arg->pages);
 209 }
 210
 211 static int gssp_alloc_receive_pages(struct gssx_arg_accept_sec_context *arg)
 212 {
 213         unsigned int i;
 214
 215         arg->npages = DIV_ROUND_UP(NGROUPS_MAX * 4, PAGE_SIZE);
 216         arg->pages = kcalloc(arg->npages, sizeof(struct page *), GFP_KERNEL);
 217         if (!arg->pages)
 218                 return -ENOMEM;
 219         for (i = 0; i < arg->npages; i++) {
 220                 arg->pages[i] = alloc_page(GFP_KERNEL);
 221                 if (!arg->pages[i]) {
 222                         gssp_free_receive_pages(arg);
 223                         return -ENOMEM;
 224                 }
 225         }
 226         return 0;
 227 }
 228
 229 static char *gssp_stringify(struct xdr_netobj *netobj)
 230 {
 231         return kmemdup_nul(netobj->data, netobj->len, GFP_KERNEL);
 232 }
 233
 234 static void gssp_hostbased_service(char **principal)
 235 {
 236         char *c;
 237
 238         if (!*principal)
 239                 return;
 240
 241         /* terminate and remove realm part */
 242         c = strchr(*principal, '@');
 243         if (c) {
 244                 *c = '\0';
 245
 246                 /* change service-hostname delimiter */
 247                 c = strchr(*principal, '/');
 248                 if (c)
 249                         *c = '@';
 250         }
 251         if (!c) {
 252                 /* not a service principal */
 253                 kfree(*principal);
 254                 *principal = NULL;
 255         }
 256 }
 257
 258 /*
 259  * Public functions
 260  */
 261
 262 /* numbers somewhat arbitrary but large enough for current needs */
 263 #define GSSX_MAX_OUT_HANDLE     128
 264 #define GSSX_MAX_SRC_PRINC      256
 265 #define GSSX_KMEMBUF (GSSX_max_output_handle_sz + \
 266                         GSSX_max_oid_sz + \
 267                         GSSX_max_princ_sz + \
 268                         sizeof(struct svc_cred))
 269
 270 int gssp_accept_sec_context_upcall(struct net *net,
 271                                 struct gssp_upcall_data *data)
 272 {
 273         struct gssx_ctx ctxh = {
 274                 .state = data->in_handle
 275         };
 276         struct gssx_arg_accept_sec_context arg = {
 277                 .input_token = data->in_token,
 278         };
 279         struct gssx_ctx rctxh = {
 280                 /*
 281                  * pass in the max length we expect for each of these
 282                  * buffers but let the xdr code kmalloc them:
 283                  */
 284                 .exported_context_token.len = GSSX_max_output_handle_sz,
 285                 .mech.len = GSS_OID_MAX_LEN,
 286                 .targ_name.display_name.len = GSSX_max_princ_sz,
 287                 .src_name.display_name.len = GSSX_max_princ_sz
 288         };
 289         struct gssx_res_accept_sec_context res = {
 290                 .context_handle = &rctxh,
 291                 .output_token = &data->out_token
 292         };
 293         struct rpc_message msg = {
 294                 .rpc_proc = &gssp_procedures[GSSX_ACCEPT_SEC_CONTEXT],
 295                 .rpc_argp = &arg,
 296                 .rpc_resp = &res,
 297                 .rpc_cred = NULL, /* FIXME ? */
 298         };
 299         struct xdr_netobj client_name = { 0 , NULL };
 300         struct xdr_netobj target_name = { 0, NULL };
 301         int ret;
 302
 303         if (data->in_handle.len != 0)
 304                 arg.context_handle = &ctxh;
 305         res.output_token->len = GSSX_max_output_token_sz;
 306
 307         ret = gssp_alloc_receive_pages(&arg);
 308         if (ret)
 309                 return ret;
 310
 311         ret = gssp_call(net, &msg);
 312
 313         gssp_free_receive_pages(&arg);
 314
 315         /* we need to fetch all data even in case of error so
 316          * that we can free special strctures is they have been allocated */
 317         data->major_status = res.status.major_status;
 318         data->minor_status = res.status.minor_status;
 319         if (res.context_handle) {
 320                 data->out_handle = rctxh.exported_context_token;
 321                 data->mech_oid.len = rctxh.mech.len;
 322                 if (rctxh.mech.data) {
 323                         memcpy(data->mech_oid.data, rctxh.mech.data,
 324                                                 data->mech_oid.len);
 325                         kfree(rctxh.mech.data);
 326                 }
 327                 client_name = rctxh.src_name.display_name;
 328                 target_name = rctxh.targ_name.display_name;
 329         }
 330
 331         if (res.options.count == 1) {
 332                 gssx_buffer *value = &res.options.data[0].value;
 333                 /* Currently we only decode CREDS_VALUE, if we add
 334                  * anything else we'll have to loop and match on the
 335                  * option name */
 336                 if (value->len == 1) {
 337                         /* steal group info from struct svc_cred */
 338                         data->creds = *(struct svc_cred *)value->data;
 339                         data->found_creds = 1;
 340                 }
 341                 /* whether we use it or not, free data */
 342                 kfree(value->data);
 343         }
 344
 345         if (res.options.count != 0) {
 346                 kfree(res.options.data);
 347         }
 348
 349         /* convert to GSS_NT_HOSTBASED_SERVICE form and set into creds */
 350         if (data->found_creds) {
 351                 if (client_name.data) {
 352                         data->creds.cr_raw_principal =
 353                                         gssp_stringify(&client_name);
 354                         data->creds.cr_principal =
 355                                         gssp_stringify(&client_name);
 356                         gssp_hostbased_service(&data->creds.cr_principal);
 357                 }
 358                 if (target_name.data) {
 359                         data->creds.cr_targ_princ =
 360                                         gssp_stringify(&target_name);
 361                         gssp_hostbased_service(&data->creds.cr_targ_princ);
 362                 }
 363         }
 364         kfree(client_name.data);
 365         kfree(target_name.data);
 366
 367         return ret;
 368 }
 369
 370 void gssp_free_upcall_data(struct gssp_upcall_data *data)
 371 {
 372         kfree(data->in_handle.data);
 373         kfree(data->out_handle.data);
 374         kfree(data->out_token.data);
 375         free_svc_cred(&data->creds);
 376 }
 377
 378 /*
 379  * Initialization stuff
 380  */
 381 static unsigned int gssp_version1_counts[ARRAY_SIZE(gssp_procedures)];
 382 static const struct rpc_version gssp_version1 = {
 383         .number         = GSSPROXY_VERS_1,
 384         .nrprocs        = ARRAY_SIZE(gssp_procedures),
 385         .procs          = gssp_procedures,
 386         .counts         = gssp_version1_counts,
 387 };
 388
 389 static const struct rpc_version *gssp_version[] = {
 390         NULL,
 391         &gssp_version1,
 392 };
 393
 394 static struct rpc_stat gssp_stats;
 395
 396 static const struct rpc_program gssp_program = {
 397         .name           = "gssproxy",
 398         .number         = GSSPROXY_PROGRAM,
 399         .nrvers         = ARRAY_SIZE(gssp_version),
 400         .version        = gssp_version,
 401         .stats          = &gssp_stats,
 402 };