xref: /linux/net/sunrpc/auth_gss/gss_rpc_upcall.c (revision 2da68a77) 
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_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 
124 void init_gssp_clnt(struct sunrpc_net *sn)
125 {
126 	mutex_init(&sn->gssp_lock);
127 	sn->gssp_clnt = NULL;
128 }
129 
130 int set_gssp_clnt(struct net *net)
131 {
132 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
133 	struct rpc_clnt *clnt;
134 	int ret;
135 
136 	mutex_lock(&sn->gssp_lock);
137 	ret = gssp_rpc_create(net, &clnt);
138 	if (!ret) {
139 		if (sn->gssp_clnt)
140 			rpc_shutdown_client(sn->gssp_clnt);
141 		sn->gssp_clnt = clnt;
142 	}
143 	mutex_unlock(&sn->gssp_lock);
144 	return ret;
145 }
146 
147 void clear_gssp_clnt(struct sunrpc_net *sn)
148 {
149 	mutex_lock(&sn->gssp_lock);
150 	if (sn->gssp_clnt) {
151 		rpc_shutdown_client(sn->gssp_clnt);
152 		sn->gssp_clnt = NULL;
153 	}
154 	mutex_unlock(&sn->gssp_lock);
155 }
156 
157 static struct rpc_clnt *get_gssp_clnt(struct sunrpc_net *sn)
158 {
159 	struct rpc_clnt *clnt;
160 
161 	mutex_lock(&sn->gssp_lock);
162 	clnt = sn->gssp_clnt;
163 	if (clnt)
164 		refcount_inc(&clnt->cl_count);
165 	mutex_unlock(&sn->gssp_lock);
166 	return clnt;
167 }
168 
169 static int gssp_call(struct net *net, struct rpc_message *msg)
170 {
171 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
172 	struct rpc_clnt *clnt;
173 	int status;
174 
175 	clnt = get_gssp_clnt(sn);
176 	if (!clnt)
177 		return -EIO;
178 	status = rpc_call_sync(clnt, msg, 0);
179 	if (status < 0) {
180 		dprintk("gssp: rpc_call returned error %d\n", -status);
181 		switch (status) {
182 		case -EPROTONOSUPPORT:
183 			status = -EINVAL;
184 			break;
185 		case -ECONNREFUSED:
186 		case -ETIMEDOUT:
187 		case -ENOTCONN:
188 			status = -EAGAIN;
189 			break;
190 		case -ERESTARTSYS:
191 			if (signalled ())
192 				status = -EINTR;
193 			break;
194 		default:
195 			break;
196 		}
197 	}
198 	rpc_release_client(clnt);
199 	return status;
200 }
201 
202 static void gssp_free_receive_pages(struct gssx_arg_accept_sec_context *arg)
203 {
204 	unsigned int i;
205 
206 	for (i = 0; i < arg->npages && arg->pages[i]; i++)
207 		__free_page(arg->pages[i]);
208 
209 	kfree(arg->pages);
210 }
211 
212 static int gssp_alloc_receive_pages(struct gssx_arg_accept_sec_context *arg)
213 {
214 	unsigned int i;
215 
216 	arg->npages = DIV_ROUND_UP(NGROUPS_MAX * 4, PAGE_SIZE);
217 	arg->pages = kcalloc(arg->npages, sizeof(struct page *), GFP_KERNEL);
218 	if (!arg->pages)
219 		return -ENOMEM;
220 	for (i = 0; i < arg->npages; i++) {
221 		arg->pages[i] = alloc_page(GFP_KERNEL);
222 		if (!arg->pages[i]) {
223 			gssp_free_receive_pages(arg);
224 			return -ENOMEM;
225 		}
226 	}
227 	return 0;
228 }
229 
230 static char *gssp_stringify(struct xdr_netobj *netobj)
231 {
232 	return kmemdup_nul(netobj->data, netobj->len, GFP_KERNEL);
233 }
234 
235 static void gssp_hostbased_service(char **principal)
236 {
237 	char *c;
238 
239 	if (!*principal)
240 		return;
241 
242 	/* terminate and remove realm part */
243 	c = strchr(*principal, '@');
244 	if (c) {
245 		*c = '\0';
246 
247 		/* change service-hostname delimiter */
248 		c = strchr(*principal, '/');
249 		if (c)
250 			*c = '@';
251 	}
252 	if (!c) {
253 		/* not a service principal */
254 		kfree(*principal);
255 		*principal = NULL;
256 	}
257 }
258 
259 /*
260  * Public functions
261  */
262 
263 /* numbers somewhat arbitrary but large enough for current needs */
264 #define GSSX_MAX_OUT_HANDLE	128
265 #define GSSX_MAX_SRC_PRINC	256
266 #define GSSX_KMEMBUF (GSSX_max_output_handle_sz + \
267 			GSSX_max_oid_sz + \
268 			GSSX_max_princ_sz + \
269 			sizeof(struct svc_cred))
270 
271 int gssp_accept_sec_context_upcall(struct net *net,
272 				struct gssp_upcall_data *data)
273 {
274 	struct gssx_ctx ctxh = {
275 		.state = data->in_handle
276 	};
277 	struct gssx_arg_accept_sec_context arg = {
278 		.input_token = data->in_token,
279 	};
280 	struct gssx_ctx rctxh = {
281 		/*
282 		 * pass in the max length we expect for each of these
283 		 * buffers but let the xdr code kmalloc them:
284 		 */
285 		.exported_context_token.len = GSSX_max_output_handle_sz,
286 		.mech.len = GSS_OID_MAX_LEN,
287 		.targ_name.display_name.len = GSSX_max_princ_sz,
288 		.src_name.display_name.len = GSSX_max_princ_sz
289 	};
290 	struct gssx_res_accept_sec_context res = {
291 		.context_handle = &rctxh,
292 		.output_token = &data->out_token
293 	};
294 	struct rpc_message msg = {
295 		.rpc_proc = &gssp_procedures[GSSX_ACCEPT_SEC_CONTEXT],
296 		.rpc_argp = &arg,
297 		.rpc_resp = &res,
298 		.rpc_cred = NULL, /* FIXME ? */
299 	};
300 	struct xdr_netobj client_name = { 0 , NULL };
301 	struct xdr_netobj target_name = { 0, NULL };
302 	int ret;
303 
304 	if (data->in_handle.len != 0)
305 		arg.context_handle = &ctxh;
306 	res.output_token->len = GSSX_max_output_token_sz;
307 
308 	ret = gssp_alloc_receive_pages(&arg);
309 	if (ret)
310 		return ret;
311 
312 	ret = gssp_call(net, &msg);
313 
314 	gssp_free_receive_pages(&arg);
315 
316 	/* we need to fetch all data even in case of error so
317 	 * that we can free special strctures is they have been allocated */
318 	data->major_status = res.status.major_status;
319 	data->minor_status = res.status.minor_status;
320 	if (res.context_handle) {
321 		data->out_handle = rctxh.exported_context_token;
322 		data->mech_oid.len = rctxh.mech.len;
323 		if (rctxh.mech.data) {
324 			memcpy(data->mech_oid.data, rctxh.mech.data,
325 						data->mech_oid.len);
326 			kfree(rctxh.mech.data);
327 		}
328 		client_name = rctxh.src_name.display_name;
329 		target_name = rctxh.targ_name.display_name;
330 	}
331 
332 	if (res.options.count == 1) {
333 		gssx_buffer *value = &res.options.data[0].value;
334 		/* Currently we only decode CREDS_VALUE, if we add
335 		 * anything else we'll have to loop and match on the
336 		 * option name */
337 		if (value->len == 1) {
338 			/* steal group info from struct svc_cred */
339 			data->creds = *(struct svc_cred *)value->data;
340 			data->found_creds = 1;
341 		}
342 		/* whether we use it or not, free data */
343 		kfree(value->data);
344 	}
345 
346 	if (res.options.count != 0) {
347 		kfree(res.options.data);
348 	}
349 
350 	/* convert to GSS_NT_HOSTBASED_SERVICE form and set into creds */
351 	if (data->found_creds) {
352 		if (client_name.data) {
353 			data->creds.cr_raw_principal =
354 					gssp_stringify(&client_name);
355 			data->creds.cr_principal =
356 					gssp_stringify(&client_name);
357 			gssp_hostbased_service(&data->creds.cr_principal);
358 		}
359 		if (target_name.data) {
360 			data->creds.cr_targ_princ =
361 					gssp_stringify(&target_name);
362 			gssp_hostbased_service(&data->creds.cr_targ_princ);
363 		}
364 	}
365 	kfree(client_name.data);
366 	kfree(target_name.data);
367 
368 	return ret;
369 }
370 
371 void gssp_free_upcall_data(struct gssp_upcall_data *data)
372 {
373 	kfree(data->in_handle.data);
374 	kfree(data->out_handle.data);
375 	kfree(data->out_token.data);
376 	free_svc_cred(&data->creds);
377 }
378 
379 /*
380  * Initialization stuff
381  */
382 static unsigned int gssp_version1_counts[ARRAY_SIZE(gssp_procedures)];
383 static const struct rpc_version gssp_version1 = {
384 	.number		= GSSPROXY_VERS_1,
385 	.nrprocs	= ARRAY_SIZE(gssp_procedures),
386 	.procs		= gssp_procedures,
387 	.counts		= gssp_version1_counts,
388 };
389 
390 static const struct rpc_version *gssp_version[] = {
391 	NULL,
392 	&gssp_version1,
393 };
394 
395 static struct rpc_stat gssp_stats;
396 
397 static const struct rpc_program gssp_program = {
398 	.name		= "gssproxy",
399 	.number		= GSSPROXY_PROGRAM,
400 	.nrvers		= ARRAY_SIZE(gssp_version),
401 	.version	= gssp_version,
402 	.stats		= &gssp_stats,
403 };
404