1/*
2 *  linux/net/sunrpc/gss_rpc_upcall.c
3 *
4 *  Copyright (C) 2012 Simo Sorce <simo@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21#include <linux/types.h>
22#include <linux/un.h>
23
24#include <linux/sunrpc/svcauth.h>
25#include "gss_rpc_upcall.h"
26
27#define GSSPROXY_SOCK_PATHNAME	"/var/run/gssproxy.sock"
28
29#define GSSPROXY_PROGRAM	(400112u)
30#define GSSPROXY_VERS_1		(1u)
31
32/*
33 * Encoding/Decoding functions
34 */
35
36enum {
37	GSSX_NULL = 0,	/* Unused */
38        GSSX_INDICATE_MECHS = 1,
39        GSSX_GET_CALL_CONTEXT = 2,
40        GSSX_IMPORT_AND_CANON_NAME = 3,
41        GSSX_EXPORT_CRED = 4,
42        GSSX_IMPORT_CRED = 5,
43        GSSX_ACQUIRE_CRED = 6,
44        GSSX_STORE_CRED = 7,
45        GSSX_INIT_SEC_CONTEXT = 8,
46        GSSX_ACCEPT_SEC_CONTEXT = 9,
47        GSSX_RELEASE_HANDLE = 10,
48        GSSX_GET_MIC = 11,
49        GSSX_VERIFY = 12,
50        GSSX_WRAP = 13,
51        GSSX_UNWRAP = 14,
52        GSSX_WRAP_SIZE_LIMIT = 15,
53};
54
55#define PROC(proc, name)				\
56[GSSX_##proc] = {					\
57	.p_proc   = GSSX_##proc,			\
58	.p_encode = (kxdreproc_t)gssx_enc_##name,	\
59	.p_decode = (kxdrdproc_t)gssx_dec_##name,	\
60	.p_arglen = GSSX_ARG_##name##_sz,		\
61	.p_replen = GSSX_RES_##name##_sz, 		\
62	.p_statidx = GSSX_##proc,			\
63	.p_name   = #proc,				\
64}
65
66static struct rpc_procinfo gssp_procedures[] = {
67	PROC(INDICATE_MECHS, indicate_mechs),
68        PROC(GET_CALL_CONTEXT, get_call_context),
69        PROC(IMPORT_AND_CANON_NAME, import_and_canon_name),
70        PROC(EXPORT_CRED, export_cred),
71        PROC(IMPORT_CRED, import_cred),
72        PROC(ACQUIRE_CRED, acquire_cred),
73        PROC(STORE_CRED, store_cred),
74        PROC(INIT_SEC_CONTEXT, init_sec_context),
75        PROC(ACCEPT_SEC_CONTEXT, accept_sec_context),
76        PROC(RELEASE_HANDLE, release_handle),
77        PROC(GET_MIC, get_mic),
78        PROC(VERIFY, verify),
79        PROC(WRAP, wrap),
80        PROC(UNWRAP, unwrap),
81        PROC(WRAP_SIZE_LIMIT, wrap_size_limit),
82};
83
84
85
86/*
87 * Common transport functions
88 */
89
90static const struct rpc_program gssp_program;
91
92static int gssp_rpc_create(struct net *net, struct rpc_clnt **_clnt)
93{
94	static const struct sockaddr_un gssp_localaddr = {
95		.sun_family		= AF_LOCAL,
96		.sun_path		= GSSPROXY_SOCK_PATHNAME,
97	};
98	struct rpc_create_args args = {
99		.net		= net,
100		.protocol	= XPRT_TRANSPORT_LOCAL,
101		.address	= (struct sockaddr *)&gssp_localaddr,
102		.addrsize	= sizeof(gssp_localaddr),
103		.servername	= "localhost",
104		.program	= &gssp_program,
105		.version	= GSSPROXY_VERS_1,
106		.authflavor	= RPC_AUTH_NULL,
107		/*
108		 * Note we want connection to be done in the caller's
109		 * filesystem namespace.  We therefore turn off the idle
110		 * timeout, which would result in reconnections being
111		 * done without the correct namespace:
112		 */
113		.flags		= RPC_CLNT_CREATE_NOPING |
114				  RPC_CLNT_CREATE_NO_IDLE_TIMEOUT
115	};
116	struct rpc_clnt *clnt;
117	int result = 0;
118
119	clnt = rpc_create(&args);
120	if (IS_ERR(clnt)) {
121		dprintk("RPC:       failed to create AF_LOCAL gssproxy "
122				"client (errno %ld).\n", PTR_ERR(clnt));
123		result = PTR_ERR(clnt);
124		*_clnt = NULL;
125		goto out;
126	}
127
128	dprintk("RPC:       created new gssp local client (gssp_local_clnt: "
129			"%p)\n", clnt);
130	*_clnt = clnt;
131
132out:
133	return result;
134}
135
136void init_gssp_clnt(struct sunrpc_net *sn)
137{
138	mutex_init(&sn->gssp_lock);
139	sn->gssp_clnt = NULL;
140}
141
142int set_gssp_clnt(struct net *net)
143{
144	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
145	struct rpc_clnt *clnt;
146	int ret;
147
148	mutex_lock(&sn->gssp_lock);
149	ret = gssp_rpc_create(net, &clnt);
150	if (!ret) {
151		if (sn->gssp_clnt)
152			rpc_shutdown_client(sn->gssp_clnt);
153		sn->gssp_clnt = clnt;
154	}
155	mutex_unlock(&sn->gssp_lock);
156	return ret;
157}
158
159void clear_gssp_clnt(struct sunrpc_net *sn)
160{
161	mutex_lock(&sn->gssp_lock);
162	if (sn->gssp_clnt) {
163		rpc_shutdown_client(sn->gssp_clnt);
164		sn->gssp_clnt = NULL;
165	}
166	mutex_unlock(&sn->gssp_lock);
167}
168
169static struct rpc_clnt *get_gssp_clnt(struct sunrpc_net *sn)
170{
171	struct rpc_clnt *clnt;
172
173	mutex_lock(&sn->gssp_lock);
174	clnt = sn->gssp_clnt;
175	if (clnt)
176		atomic_inc(&clnt->cl_count);
177	mutex_unlock(&sn->gssp_lock);
178	return clnt;
179}
180
181static int gssp_call(struct net *net, struct rpc_message *msg)
182{
183	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
184	struct rpc_clnt *clnt;
185	int status;
186
187	clnt = get_gssp_clnt(sn);
188	if (!clnt)
189		return -EIO;
190	status = rpc_call_sync(clnt, msg, 0);
191	if (status < 0) {
192		dprintk("gssp: rpc_call returned error %d\n", -status);
193		switch (status) {
194		case -EPROTONOSUPPORT:
195			status = -EINVAL;
196			break;
197		case -ECONNREFUSED:
198		case -ETIMEDOUT:
199		case -ENOTCONN:
200			status = -EAGAIN;
201			break;
202		case -ERESTARTSYS:
203			if (signalled ())
204				status = -EINTR;
205			break;
206		default:
207			break;
208		}
209	}
210	rpc_release_client(clnt);
211	return status;
212}
213
214static void gssp_free_receive_pages(struct gssx_arg_accept_sec_context *arg)
215{
216	int i;
217
218	for (i = 0; i < arg->npages && arg->pages[i]; i++)
219		__free_page(arg->pages[i]);
220}
221
222static int gssp_alloc_receive_pages(struct gssx_arg_accept_sec_context *arg)
223{
224	arg->npages = DIV_ROUND_UP(NGROUPS_MAX * 4, PAGE_SIZE);
225	arg->pages = kzalloc(arg->npages * sizeof(struct page *), GFP_KERNEL);
226	/*
227	 * XXX: actual pages are allocated by xdr layer in
228	 * xdr_partial_copy_from_skb.
229	 */
230	if (!arg->pages)
231		return -ENOMEM;
232	return 0;
233}
234
235/*
236 * Public functions
237 */
238
239/* numbers somewhat arbitrary but large enough for current needs */
240#define GSSX_MAX_OUT_HANDLE	128
241#define GSSX_MAX_SRC_PRINC	256
242#define GSSX_KMEMBUF (GSSX_max_output_handle_sz + \
243			GSSX_max_oid_sz + \
244			GSSX_max_princ_sz + \
245			sizeof(struct svc_cred))
246
247int gssp_accept_sec_context_upcall(struct net *net,
248				struct gssp_upcall_data *data)
249{
250	struct gssx_ctx ctxh = {
251		.state = data->in_handle
252	};
253	struct gssx_arg_accept_sec_context arg = {
254		.input_token = data->in_token,
255	};
256	struct gssx_ctx rctxh = {
257		/*
258		 * pass in the max length we expect for each of these
259		 * buffers but let the xdr code kmalloc them:
260		 */
261		.exported_context_token.len = GSSX_max_output_handle_sz,
262		.mech.len = GSS_OID_MAX_LEN,
263		.src_name.display_name.len = GSSX_max_princ_sz
264	};
265	struct gssx_res_accept_sec_context res = {
266		.context_handle = &rctxh,
267		.output_token = &data->out_token
268	};
269	struct rpc_message msg = {
270		.rpc_proc = &gssp_procedures[GSSX_ACCEPT_SEC_CONTEXT],
271		.rpc_argp = &arg,
272		.rpc_resp = &res,
273		.rpc_cred = NULL, /* FIXME ? */
274	};
275	struct xdr_netobj client_name = { 0 , NULL };
276	int ret;
277
278	if (data->in_handle.len != 0)
279		arg.context_handle = &ctxh;
280	res.output_token->len = GSSX_max_output_token_sz;
281
282	ret = gssp_alloc_receive_pages(&arg);
283	if (ret)
284		return ret;
285
286	/* use nfs/ for targ_name ? */
287
288	ret = gssp_call(net, &msg);
289
290	gssp_free_receive_pages(&arg);
291
292	/* we need to fetch all data even in case of error so
293	 * that we can free special strctures is they have been allocated */
294	data->major_status = res.status.major_status;
295	data->minor_status = res.status.minor_status;
296	if (res.context_handle) {
297		data->out_handle = rctxh.exported_context_token;
298		data->mech_oid.len = rctxh.mech.len;
299		if (rctxh.mech.data)
300			memcpy(data->mech_oid.data, rctxh.mech.data,
301						data->mech_oid.len);
302		client_name = rctxh.src_name.display_name;
303	}
304
305	if (res.options.count == 1) {
306		gssx_buffer *value = &res.options.data[0].value;
307		/* Currently we only decode CREDS_VALUE, if we add
308		 * anything else we'll have to loop and match on the
309		 * option name */
310		if (value->len == 1) {
311			/* steal group info from struct svc_cred */
312			data->creds = *(struct svc_cred *)value->data;
313			data->found_creds = 1;
314		}
315		/* whether we use it or not, free data */
316		kfree(value->data);
317	}
318
319	if (res.options.count != 0) {
320		kfree(res.options.data);
321	}
322
323	/* convert to GSS_NT_HOSTBASED_SERVICE form and set into creds */
324	if (data->found_creds && client_name.data != NULL) {
325		char *c;
326
327		data->creds.cr_principal = kstrndup(client_name.data,
328						client_name.len, GFP_KERNEL);
329		if (data->creds.cr_principal) {
330			/* terminate and remove realm part */
331			c = strchr(data->creds.cr_principal, '@');
332			if (c) {
333				*c = '\0';
334
335				/* change service-hostname delimiter */
336				c = strchr(data->creds.cr_principal, '/');
337				if (c) *c = '@';
338			}
339			if (!c) {
340				/* not a service principal */
341				kfree(data->creds.cr_principal);
342				data->creds.cr_principal = NULL;
343			}
344		}
345	}
346	kfree(client_name.data);
347
348	return ret;
349}
350
351void gssp_free_upcall_data(struct gssp_upcall_data *data)
352{
353	kfree(data->in_handle.data);
354	kfree(data->out_handle.data);
355	kfree(data->out_token.data);
356	free_svc_cred(&data->creds);
357}
358
359/*
360 * Initialization stuff
361 */
362
363static const struct rpc_version gssp_version1 = {
364	.number		= GSSPROXY_VERS_1,
365	.nrprocs	= ARRAY_SIZE(gssp_procedures),
366	.procs		= gssp_procedures,
367};
368
369static const struct rpc_version *gssp_version[] = {
370	NULL,
371	&gssp_version1,
372};
373
374static struct rpc_stat gssp_stats;
375
376static const struct rpc_program gssp_program = {
377	.name		= "gssproxy",
378	.number		= GSSPROXY_PROGRAM,
379	.nrvers		= ARRAY_SIZE(gssp_version),
380	.version	= gssp_version,
381	.stats		= &gssp_stats,
382};
383