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         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         arg->npages = DIV_ROUND_UP(NGROUPS_MAX * 4, PAGE_SIZE);
 214         arg->pages = kcalloc(arg->npages, sizeof(struct page *), GFP_KERNEL);
 215         /*
 216          * XXX: actual pages are allocated by xdr layer in
 217          * xdr_partial_copy_from_skb.
 218          */
 219         if (!arg->pages)
 220                 return -ENOMEM;
 221         return 0;
 222 }
 223
 224 static char *gssp_stringify(struct xdr_netobj *netobj)
 225 {
 226         return kstrndup(netobj->data, netobj->len, GFP_KERNEL);
 227 }
 228
 229 static void gssp_hostbased_service(char **principal)
 230 {
 231         char *c;
 232
 233         if (!*principal)
 234                 return;
 235
 236         /* terminate and remove realm part */
 237         c = strchr(*principal, '@');
 238         if (c) {
 239                 *c = '\0';
 240
 241                 /* change service-hostname delimiter */
 242                 c = strchr(*principal, '/');
 243                 if (c)
 244                         *c = '@';
 245         }
 246         if (!c) {
 247                 /* not a service principal */
 248                 kfree(*principal);
 249                 *principal = NULL;
 250         }
 251 }
 252
 253 /*
 254  * Public functions
 255  */
 256
 257 /* numbers somewhat arbitrary but large enough for current needs */
 258 #define GSSX_MAX_OUT_HANDLE     128
 259 #define GSSX_MAX_SRC_PRINC      256
 260 #define GSSX_KMEMBUF (GSSX_max_output_handle_sz + \
 261                         GSSX_max_oid_sz + \
 262                         GSSX_max_princ_sz + \
 263                         sizeof(struct svc_cred))
 264
 265 int gssp_accept_sec_context_upcall(struct net *net,
 266                                 struct gssp_upcall_data *data)
 267 {
 268         struct gssx_ctx ctxh = {
 269                 .state = data->in_handle
 270         };
 271         struct gssx_arg_accept_sec_context arg = {
 272                 .input_token = data->in_token,
 273         };
 274         struct gssx_ctx rctxh = {
 275                 /*
 276                  * pass in the max length we expect for each of these
 277                  * buffers but let the xdr code kmalloc them:
 278                  */
 279                 .exported_context_token.len = GSSX_max_output_handle_sz,
 280                 .mech.len = GSS_OID_MAX_LEN,
 281                 .targ_name.display_name.len = GSSX_max_princ_sz,
 282                 .src_name.display_name.len = GSSX_max_princ_sz
 283         };
 284         struct gssx_res_accept_sec_context res = {
 285                 .context_handle = &rctxh,
 286                 .output_token = &data->out_token
 287         };
 288         struct rpc_message msg = {
 289                 .rpc_proc = &gssp_procedures[GSSX_ACCEPT_SEC_CONTEXT],
 290                 .rpc_argp = &arg,
 291                 .rpc_resp = &res,
 292                 .rpc_cred = NULL, /* FIXME ? */
 293         };
 294         struct xdr_netobj client_name = { 0 , NULL };
 295         struct xdr_netobj target_name = { 0, NULL };
 296         int ret;
 297
 298         if (data->in_handle.len != 0)
 299                 arg.context_handle = &ctxh;
 300         res.output_token->len = GSSX_max_output_token_sz;
 301
 302         ret = gssp_alloc_receive_pages(&arg);
 303         if (ret)
 304                 return ret;
 305
 306         ret = gssp_call(net, &msg);
 307
 308         gssp_free_receive_pages(&arg);
 309
 310         /* we need to fetch all data even in case of error so
 311          * that we can free special strctures is they have been allocated */
 312         data->major_status = res.status.major_status;
 313         data->minor_status = res.status.minor_status;
 314         if (res.context_handle) {
 315                 data->out_handle = rctxh.exported_context_token;
 316                 data->mech_oid.len = rctxh.mech.len;
 317                 if (rctxh.mech.data) {
 318                         memcpy(data->mech_oid.data, rctxh.mech.data,
 319                                                 data->mech_oid.len);
 320                         kfree(rctxh.mech.data);
 321                 }
 322                 client_name = rctxh.src_name.display_name;
 323                 target_name = rctxh.targ_name.display_name;
 324         }
 325
 326         if (res.options.count == 1) {
 327                 gssx_buffer *value = &res.options.data[0].value;
 328                 /* Currently we only decode CREDS_VALUE, if we add
 329                  * anything else we'll have to loop and match on the
 330                  * option name */
 331                 if (value->len == 1) {
 332                         /* steal group info from struct svc_cred */
 333                         data->creds = *(struct svc_cred *)value->data;
 334                         data->found_creds = 1;
 335                 }
 336                 /* whether we use it or not, free data */
 337                 kfree(value->data);
 338         }
 339
 340         if (res.options.count != 0) {
 341                 kfree(res.options.data);
 342         }
 343
 344         /* convert to GSS_NT_HOSTBASED_SERVICE form and set into creds */
 345         if (data->found_creds) {
 346                 if (client_name.data) {
 347                         data->creds.cr_raw_principal =
 348                                         gssp_stringify(&client_name);
 349                         data->creds.cr_principal =
 350                                         gssp_stringify(&client_name);
 351                         gssp_hostbased_service(&data->creds.cr_principal);
 352                 }
 353                 if (target_name.data) {
 354                         data->creds.cr_targ_princ =
 355                                         gssp_stringify(&target_name);
 356                         gssp_hostbased_service(&data->creds.cr_targ_princ);
 357                 }
 358         }
 359         kfree(client_name.data);
 360         kfree(target_name.data);
 361
 362         return ret;
 363 }
 364
 365 void gssp_free_upcall_data(struct gssp_upcall_data *data)
 366 {
 367         kfree(data->in_handle.data);
 368         kfree(data->out_handle.data);
 369         kfree(data->out_token.data);
 370         free_svc_cred(&data->creds);
 371 }
 372
 373 /*
 374  * Initialization stuff
 375  */
 376 static unsigned int gssp_version1_counts[ARRAY_SIZE(gssp_procedures)];
 377 static const struct rpc_version gssp_version1 = {
 378         .number         = GSSPROXY_VERS_1,
 379         .nrprocs        = ARRAY_SIZE(gssp_procedures),
 380         .procs          = gssp_procedures,
 381         .counts         = gssp_version1_counts,
 382 };
 383
 384 static const struct rpc_version *gssp_version[] = {
 385         NULL,
 386         &gssp_version1,
 387 };
 388
 389 static struct rpc_stat gssp_stats;
 390
 391 static const struct rpc_program gssp_program = {
 392         .name           = "gssproxy",
 393         .number         = GSSPROXY_PROGRAM,
 394         .nrvers         = ARRAY_SIZE(gssp_version),
 395         .version        = gssp_version,
 396         .stats          = &gssp_stats,
 397 };