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_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
init_gssp_clnt(struct sunrpc_net * sn)123 void init_gssp_clnt(struct sunrpc_net *sn)
124 {
125 mutex_init(&sn->gssp_lock);
126 sn->gssp_clnt = NULL;
127 }
128
set_gssp_clnt(struct net * net)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
clear_gssp_clnt(struct sunrpc_net * sn)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
get_gssp_clnt(struct sunrpc_net * sn)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
gssp_call(struct net * net,struct rpc_message * msg)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
gssp_free_receive_pages(struct gssx_arg_accept_sec_context * arg)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
gssp_alloc_receive_pages(struct gssx_arg_accept_sec_context * arg)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
gssp_stringify(struct xdr_netobj * netobj)229 static char *gssp_stringify(struct xdr_netobj *netobj)
230 {
231 return kmemdup_nul(netobj->data, netobj->len, GFP_KERNEL);
232 }
233
gssp_hostbased_service(char ** principal)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
gssp_accept_sec_context_upcall(struct net * net,struct gssp_upcall_data * data)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
gssp_free_upcall_data(struct gssp_upcall_data * data)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 };
403