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
23enum {
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
53static 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
77static const struct rpc_program gssp_program;
78
79static 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
120out:
121	return result;
122}
123
124void init_gssp_clnt(struct sunrpc_net *sn)
125{
126	mutex_init(&sn->gssp_lock);
127	sn->gssp_clnt = NULL;
128}
129
130int 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
147void 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
157static 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
169static 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
202static 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
212static 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
230static char *gssp_stringify(struct xdr_netobj *netobj)
231{
232	return kmemdup_nul(netobj->data, netobj->len, GFP_KERNEL);
233}
234
235static 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
271int 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
371void 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 */
382static unsigned int gssp_version1_counts[ARRAY_SIZE(gssp_procedures)];
383static 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
390static const struct rpc_version *gssp_version[] = {
391	NULL,
392	&gssp_version1,
393};
394
395static struct rpc_stat gssp_stats;
396
397static 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