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