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
gssp_rpc_create(struct net * net,struct rpc_clnt ** _clnt)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
set_gssp_clnt(struct net * net)124 int set_gssp_clnt(struct net *net)
125 {
126 struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
127 struct rpc_clnt *clnt;
128 int ret;
129
130 mutex_lock(&sn->gssp_lock);
131 ret = gssp_rpc_create(net, &clnt);
132 if (!ret) {
133 if (sn->gssp_clnt)
134 rpc_shutdown_client(sn->gssp_clnt);
135 sn->gssp_clnt = clnt;
136 }
137 mutex_unlock(&sn->gssp_lock);
138 return ret;
139 }
140
clear_gssp_clnt(struct sunrpc_net * sn)141 void clear_gssp_clnt(struct sunrpc_net *sn)
142 {
143 mutex_lock(&sn->gssp_lock);
144 if (sn->gssp_clnt) {
145 rpc_shutdown_client(sn->gssp_clnt);
146 sn->gssp_clnt = NULL;
147 }
148 mutex_unlock(&sn->gssp_lock);
149 }
150
get_gssp_clnt(struct sunrpc_net * sn)151 static struct rpc_clnt *get_gssp_clnt(struct sunrpc_net *sn)
152 {
153 struct rpc_clnt *clnt;
154
155 mutex_lock(&sn->gssp_lock);
156 clnt = sn->gssp_clnt;
157 if (clnt)
158 refcount_inc(&clnt->cl_count);
159 mutex_unlock(&sn->gssp_lock);
160 return clnt;
161 }
162
gssp_call(struct net * net,struct rpc_message * msg)163 static int gssp_call(struct net *net, struct rpc_message *msg)
164 {
165 struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
166 struct rpc_clnt *clnt;
167 int status;
168
169 clnt = get_gssp_clnt(sn);
170 if (!clnt)
171 return -EIO;
172 status = rpc_call_sync(clnt, msg, 0);
173 if (status < 0) {
174 dprintk("gssp: rpc_call returned error %d\n", -status);
175 switch (status) {
176 case -EPROTONOSUPPORT:
177 status = -EINVAL;
178 break;
179 case -ECONNREFUSED:
180 case -ETIMEDOUT:
181 case -ENOTCONN:
182 status = -EAGAIN;
183 break;
184 case -ERESTARTSYS:
185 if (signalled ())
186 status = -EINTR;
187 break;
188 default:
189 break;
190 }
191 }
192 rpc_release_client(clnt);
193 return status;
194 }
195
gssp_free_receive_pages(struct gssx_arg_accept_sec_context * arg)196 static void gssp_free_receive_pages(struct gssx_arg_accept_sec_context *arg)
197 {
198 unsigned int i;
199
200 for (i = 0; i < arg->npages && arg->pages[i]; i++)
201 __free_page(arg->pages[i]);
202
203 kfree(arg->pages);
204 }
205
gssp_alloc_receive_pages(struct gssx_arg_accept_sec_context * arg)206 static int gssp_alloc_receive_pages(struct gssx_arg_accept_sec_context *arg)
207 {
208 unsigned int i;
209
210 arg->npages = DIV_ROUND_UP(NGROUPS_MAX * 4, PAGE_SIZE);
211 arg->pages = kzalloc_objs(struct page *, arg->npages);
212 if (!arg->pages)
213 return -ENOMEM;
214 for (i = 0; i < arg->npages; i++) {
215 arg->pages[i] = alloc_page(GFP_KERNEL);
216 if (!arg->pages[i]) {
217 gssp_free_receive_pages(arg);
218 return -ENOMEM;
219 }
220 }
221 return 0;
222 }
223
gssp_stringify(struct xdr_netobj * netobj)224 static char *gssp_stringify(struct xdr_netobj *netobj)
225 {
226 return kmemdup_nul(netobj->data, netobj->len, GFP_KERNEL);
227 }
228
gssp_hostbased_service(char ** principal)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
gssp_accept_sec_context_upcall(struct net * net,struct gssp_upcall_data * data)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
gssp_free_upcall_data(struct gssp_upcall_data * data)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 };
398