linux/net/sunrpc/auth_gss/gss_rpc_upcall.c
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   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
  23enum {
  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
  53static 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
  77static const struct rpc_program gssp_program;
  78
  79static 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
 119out:
 120        return result;
 121}
 122
 123void init_gssp_clnt(struct sunrpc_net *sn)
 124{
 125        mutex_init(&sn->gssp_lock);
 126        sn->gssp_clnt = NULL;
 127}
 128
 129int 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
 146void 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
 156static 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                refcount_inc(&clnt->cl_count);
 164        mutex_unlock(&sn->gssp_lock);
 165        return clnt;
 166}
 167
 168static 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
 201static 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
 211static 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
 229static char *gssp_stringify(struct xdr_netobj *netobj)
 230{
 231        return kmemdup_nul(netobj->data, netobj->len, GFP_KERNEL);
 232}
 233
 234static 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
 270int 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
 370void 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 */
 381static unsigned int gssp_version1_counts[ARRAY_SIZE(gssp_procedures)];
 382static 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
 389static const struct rpc_version *gssp_version[] = {
 390        NULL,
 391        &gssp_version1,
 392};
 393
 394static struct rpc_stat gssp_stats;
 395
 396static 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};
 403