xref: /openbmc/linux/net/sunrpc/svcauth_unix.c (revision 87c2ce3b)
1 #include <linux/types.h>
2 #include <linux/sched.h>
3 #include <linux/module.h>
4 #include <linux/sunrpc/types.h>
5 #include <linux/sunrpc/xdr.h>
6 #include <linux/sunrpc/svcsock.h>
7 #include <linux/sunrpc/svcauth.h>
8 #include <linux/err.h>
9 #include <linux/seq_file.h>
10 #include <linux/hash.h>
11 #include <linux/string.h>
12 
13 #define RPCDBG_FACILITY	RPCDBG_AUTH
14 
15 
16 /*
17  * AUTHUNIX and AUTHNULL credentials are both handled here.
18  * AUTHNULL is treated just like AUTHUNIX except that the uid/gid
19  * are always nobody (-2).  i.e. we do the same IP address checks for
20  * AUTHNULL as for AUTHUNIX, and that is done here.
21  */
22 
23 
24 struct unix_domain {
25 	struct auth_domain	h;
26 	int	addr_changes;
27 	/* other stuff later */
28 };
29 
30 struct auth_domain *unix_domain_find(char *name)
31 {
32 	struct auth_domain *rv, ud;
33 	struct unix_domain *new;
34 
35 	ud.name = name;
36 
37 	rv = auth_domain_lookup(&ud, 0);
38 
39  foundit:
40 	if (rv && rv->flavour != RPC_AUTH_UNIX) {
41 		auth_domain_put(rv);
42 		return NULL;
43 	}
44 	if (rv)
45 		return rv;
46 
47 	new = kmalloc(sizeof(*new), GFP_KERNEL);
48 	if (new == NULL)
49 		return NULL;
50 	cache_init(&new->h.h);
51 	new->h.name = kstrdup(name, GFP_KERNEL);
52 	new->h.flavour = RPC_AUTH_UNIX;
53 	new->addr_changes = 0;
54 	new->h.h.expiry_time = NEVER;
55 
56 	rv = auth_domain_lookup(&new->h, 2);
57 	if (rv == &new->h) {
58 		if (atomic_dec_and_test(&new->h.h.refcnt)) BUG();
59 	} else {
60 		auth_domain_put(&new->h);
61 		goto foundit;
62 	}
63 
64 	return rv;
65 }
66 
67 static void svcauth_unix_domain_release(struct auth_domain *dom)
68 {
69 	struct unix_domain *ud = container_of(dom, struct unix_domain, h);
70 
71 	kfree(dom->name);
72 	kfree(ud);
73 }
74 
75 
76 /**************************************************
77  * cache for IP address to unix_domain
78  * as needed by AUTH_UNIX
79  */
80 #define	IP_HASHBITS	8
81 #define	IP_HASHMAX	(1<<IP_HASHBITS)
82 #define	IP_HASHMASK	(IP_HASHMAX-1)
83 
84 struct ip_map {
85 	struct cache_head	h;
86 	char			m_class[8]; /* e.g. "nfsd" */
87 	struct in_addr		m_addr;
88 	struct unix_domain	*m_client;
89 	int			m_add_change;
90 };
91 static struct cache_head	*ip_table[IP_HASHMAX];
92 
93 static void ip_map_put(struct cache_head *item, struct cache_detail *cd)
94 {
95 	struct ip_map *im = container_of(item, struct ip_map,h);
96 	if (cache_put(item, cd)) {
97 		if (test_bit(CACHE_VALID, &item->flags) &&
98 		    !test_bit(CACHE_NEGATIVE, &item->flags))
99 			auth_domain_put(&im->m_client->h);
100 		kfree(im);
101 	}
102 }
103 
104 #if IP_HASHBITS == 8
105 /* hash_long on a 64 bit machine is currently REALLY BAD for
106  * IP addresses in reverse-endian (i.e. on a little-endian machine).
107  * So use a trivial but reliable hash instead
108  */
109 static inline int hash_ip(unsigned long ip)
110 {
111 	int hash = ip ^ (ip>>16);
112 	return (hash ^ (hash>>8)) & 0xff;
113 }
114 #endif
115 
116 static inline int ip_map_hash(struct ip_map *item)
117 {
118 	return hash_str(item->m_class, IP_HASHBITS) ^
119 		hash_ip((unsigned long)item->m_addr.s_addr);
120 }
121 static inline int ip_map_match(struct ip_map *item, struct ip_map *tmp)
122 {
123 	return strcmp(tmp->m_class, item->m_class) == 0
124 		&& tmp->m_addr.s_addr == item->m_addr.s_addr;
125 }
126 static inline void ip_map_init(struct ip_map *new, struct ip_map *item)
127 {
128 	strcpy(new->m_class, item->m_class);
129 	new->m_addr.s_addr = item->m_addr.s_addr;
130 }
131 static inline void ip_map_update(struct ip_map *new, struct ip_map *item)
132 {
133 	cache_get(&item->m_client->h.h);
134 	new->m_client = item->m_client;
135 	new->m_add_change = item->m_add_change;
136 }
137 
138 static void ip_map_request(struct cache_detail *cd,
139 				  struct cache_head *h,
140 				  char **bpp, int *blen)
141 {
142 	char text_addr[20];
143 	struct ip_map *im = container_of(h, struct ip_map, h);
144 	__u32 addr = im->m_addr.s_addr;
145 
146 	snprintf(text_addr, 20, "%u.%u.%u.%u",
147 		 ntohl(addr) >> 24 & 0xff,
148 		 ntohl(addr) >> 16 & 0xff,
149 		 ntohl(addr) >>  8 & 0xff,
150 		 ntohl(addr) >>  0 & 0xff);
151 
152 	qword_add(bpp, blen, im->m_class);
153 	qword_add(bpp, blen, text_addr);
154 	(*bpp)[-1] = '\n';
155 }
156 
157 static struct ip_map *ip_map_lookup(struct ip_map *, int);
158 
159 static int ip_map_parse(struct cache_detail *cd,
160 			  char *mesg, int mlen)
161 {
162 	/* class ipaddress [domainname] */
163 	/* should be safe just to use the start of the input buffer
164 	 * for scratch: */
165 	char *buf = mesg;
166 	int len;
167 	int b1,b2,b3,b4;
168 	char c;
169 	struct ip_map ipm, *ipmp;
170 	struct auth_domain *dom;
171 	time_t expiry;
172 
173 	if (mesg[mlen-1] != '\n')
174 		return -EINVAL;
175 	mesg[mlen-1] = 0;
176 
177 	/* class */
178 	len = qword_get(&mesg, ipm.m_class, sizeof(ipm.m_class));
179 	if (len <= 0) return -EINVAL;
180 
181 	/* ip address */
182 	len = qword_get(&mesg, buf, mlen);
183 	if (len <= 0) return -EINVAL;
184 
185 	if (sscanf(buf, "%u.%u.%u.%u%c", &b1, &b2, &b3, &b4, &c) != 4)
186 		return -EINVAL;
187 
188 	expiry = get_expiry(&mesg);
189 	if (expiry ==0)
190 		return -EINVAL;
191 
192 	/* domainname, or empty for NEGATIVE */
193 	len = qword_get(&mesg, buf, mlen);
194 	if (len < 0) return -EINVAL;
195 
196 	if (len) {
197 		dom = unix_domain_find(buf);
198 		if (dom == NULL)
199 			return -ENOENT;
200 	} else
201 		dom = NULL;
202 
203 	ipm.m_addr.s_addr =
204 		htonl((((((b1<<8)|b2)<<8)|b3)<<8)|b4);
205 	ipm.h.flags = 0;
206 	if (dom) {
207 		ipm.m_client = container_of(dom, struct unix_domain, h);
208 		ipm.m_add_change = ipm.m_client->addr_changes;
209 	} else
210 		set_bit(CACHE_NEGATIVE, &ipm.h.flags);
211 	ipm.h.expiry_time = expiry;
212 
213 	ipmp = ip_map_lookup(&ipm, 1);
214 	if (ipmp)
215 		ip_map_put(&ipmp->h, &ip_map_cache);
216 	if (dom)
217 		auth_domain_put(dom);
218 	if (!ipmp)
219 		return -ENOMEM;
220 	cache_flush();
221 	return 0;
222 }
223 
224 static int ip_map_show(struct seq_file *m,
225 		       struct cache_detail *cd,
226 		       struct cache_head *h)
227 {
228 	struct ip_map *im;
229 	struct in_addr addr;
230 	char *dom = "-no-domain-";
231 
232 	if (h == NULL) {
233 		seq_puts(m, "#class IP domain\n");
234 		return 0;
235 	}
236 	im = container_of(h, struct ip_map, h);
237 	/* class addr domain */
238 	addr = im->m_addr;
239 
240 	if (test_bit(CACHE_VALID, &h->flags) &&
241 	    !test_bit(CACHE_NEGATIVE, &h->flags))
242 		dom = im->m_client->h.name;
243 
244 	seq_printf(m, "%s %d.%d.%d.%d %s\n",
245 		   im->m_class,
246 		   htonl(addr.s_addr) >> 24 & 0xff,
247 		   htonl(addr.s_addr) >> 16 & 0xff,
248 		   htonl(addr.s_addr) >>  8 & 0xff,
249 		   htonl(addr.s_addr) >>  0 & 0xff,
250 		   dom
251 		   );
252 	return 0;
253 }
254 
255 
256 struct cache_detail ip_map_cache = {
257 	.owner		= THIS_MODULE,
258 	.hash_size	= IP_HASHMAX,
259 	.hash_table	= ip_table,
260 	.name		= "auth.unix.ip",
261 	.cache_put	= ip_map_put,
262 	.cache_request	= ip_map_request,
263 	.cache_parse	= ip_map_parse,
264 	.cache_show	= ip_map_show,
265 };
266 
267 static DefineSimpleCacheLookup(ip_map, 0)
268 
269 
270 int auth_unix_add_addr(struct in_addr addr, struct auth_domain *dom)
271 {
272 	struct unix_domain *udom;
273 	struct ip_map ip, *ipmp;
274 
275 	if (dom->flavour != RPC_AUTH_UNIX)
276 		return -EINVAL;
277 	udom = container_of(dom, struct unix_domain, h);
278 	strcpy(ip.m_class, "nfsd");
279 	ip.m_addr = addr;
280 	ip.m_client = udom;
281 	ip.m_add_change = udom->addr_changes+1;
282 	ip.h.flags = 0;
283 	ip.h.expiry_time = NEVER;
284 
285 	ipmp = ip_map_lookup(&ip, 1);
286 
287 	if (ipmp) {
288 		ip_map_put(&ipmp->h, &ip_map_cache);
289 		return 0;
290 	} else
291 		return -ENOMEM;
292 }
293 
294 int auth_unix_forget_old(struct auth_domain *dom)
295 {
296 	struct unix_domain *udom;
297 
298 	if (dom->flavour != RPC_AUTH_UNIX)
299 		return -EINVAL;
300 	udom = container_of(dom, struct unix_domain, h);
301 	udom->addr_changes++;
302 	return 0;
303 }
304 
305 struct auth_domain *auth_unix_lookup(struct in_addr addr)
306 {
307 	struct ip_map key, *ipm;
308 	struct auth_domain *rv;
309 
310 	strcpy(key.m_class, "nfsd");
311 	key.m_addr = addr;
312 
313 	ipm = ip_map_lookup(&key, 0);
314 
315 	if (!ipm)
316 		return NULL;
317 	if (cache_check(&ip_map_cache, &ipm->h, NULL))
318 		return NULL;
319 
320 	if ((ipm->m_client->addr_changes - ipm->m_add_change) >0) {
321 		if (test_and_set_bit(CACHE_NEGATIVE, &ipm->h.flags) == 0)
322 			auth_domain_put(&ipm->m_client->h);
323 		rv = NULL;
324 	} else {
325 		rv = &ipm->m_client->h;
326 		cache_get(&rv->h);
327 	}
328 	ip_map_put(&ipm->h, &ip_map_cache);
329 	return rv;
330 }
331 
332 void svcauth_unix_purge(void)
333 {
334 	cache_purge(&ip_map_cache);
335 	cache_purge(&auth_domain_cache);
336 }
337 
338 static int
339 svcauth_unix_set_client(struct svc_rqst *rqstp)
340 {
341 	struct ip_map key, *ipm;
342 
343 	rqstp->rq_client = NULL;
344 	if (rqstp->rq_proc == 0)
345 		return SVC_OK;
346 
347 	strcpy(key.m_class, rqstp->rq_server->sv_program->pg_class);
348 	key.m_addr = rqstp->rq_addr.sin_addr;
349 
350 	ipm = ip_map_lookup(&key, 0);
351 
352 	if (ipm == NULL)
353 		return SVC_DENIED;
354 
355 	switch (cache_check(&ip_map_cache, &ipm->h, &rqstp->rq_chandle)) {
356 		default:
357 			BUG();
358 		case -EAGAIN:
359 			return SVC_DROP;
360 		case -ENOENT:
361 			return SVC_DENIED;
362 		case 0:
363 			rqstp->rq_client = &ipm->m_client->h;
364 			cache_get(&rqstp->rq_client->h);
365 			ip_map_put(&ipm->h, &ip_map_cache);
366 			break;
367 	}
368 	return SVC_OK;
369 }
370 
371 static int
372 svcauth_null_accept(struct svc_rqst *rqstp, u32 *authp)
373 {
374 	struct kvec	*argv = &rqstp->rq_arg.head[0];
375 	struct kvec	*resv = &rqstp->rq_res.head[0];
376 	struct svc_cred	*cred = &rqstp->rq_cred;
377 
378 	cred->cr_group_info = NULL;
379 	rqstp->rq_client = NULL;
380 
381 	if (argv->iov_len < 3*4)
382 		return SVC_GARBAGE;
383 
384 	if (svc_getu32(argv) != 0) {
385 		dprintk("svc: bad null cred\n");
386 		*authp = rpc_autherr_badcred;
387 		return SVC_DENIED;
388 	}
389 	if (svc_getu32(argv) != RPC_AUTH_NULL || svc_getu32(argv) != 0) {
390 		dprintk("svc: bad null verf\n");
391 		*authp = rpc_autherr_badverf;
392 		return SVC_DENIED;
393 	}
394 
395 	/* Signal that mapping to nobody uid/gid is required */
396 	cred->cr_uid = (uid_t) -1;
397 	cred->cr_gid = (gid_t) -1;
398 	cred->cr_group_info = groups_alloc(0);
399 	if (cred->cr_group_info == NULL)
400 		return SVC_DROP; /* kmalloc failure - client must retry */
401 
402 	/* Put NULL verifier */
403 	svc_putu32(resv, RPC_AUTH_NULL);
404 	svc_putu32(resv, 0);
405 
406 	return SVC_OK;
407 }
408 
409 static int
410 svcauth_null_release(struct svc_rqst *rqstp)
411 {
412 	if (rqstp->rq_client)
413 		auth_domain_put(rqstp->rq_client);
414 	rqstp->rq_client = NULL;
415 	if (rqstp->rq_cred.cr_group_info)
416 		put_group_info(rqstp->rq_cred.cr_group_info);
417 	rqstp->rq_cred.cr_group_info = NULL;
418 
419 	return 0; /* don't drop */
420 }
421 
422 
423 struct auth_ops svcauth_null = {
424 	.name		= "null",
425 	.owner		= THIS_MODULE,
426 	.flavour	= RPC_AUTH_NULL,
427 	.accept 	= svcauth_null_accept,
428 	.release	= svcauth_null_release,
429 	.set_client	= svcauth_unix_set_client,
430 };
431 
432 
433 static int
434 svcauth_unix_accept(struct svc_rqst *rqstp, u32 *authp)
435 {
436 	struct kvec	*argv = &rqstp->rq_arg.head[0];
437 	struct kvec	*resv = &rqstp->rq_res.head[0];
438 	struct svc_cred	*cred = &rqstp->rq_cred;
439 	u32		slen, i;
440 	int		len   = argv->iov_len;
441 
442 	cred->cr_group_info = NULL;
443 	rqstp->rq_client = NULL;
444 
445 	if ((len -= 3*4) < 0)
446 		return SVC_GARBAGE;
447 
448 	svc_getu32(argv);			/* length */
449 	svc_getu32(argv);			/* time stamp */
450 	slen = XDR_QUADLEN(ntohl(svc_getu32(argv)));	/* machname length */
451 	if (slen > 64 || (len -= (slen + 3)*4) < 0)
452 		goto badcred;
453 	argv->iov_base = (void*)((u32*)argv->iov_base + slen);	/* skip machname */
454 	argv->iov_len -= slen*4;
455 
456 	cred->cr_uid = ntohl(svc_getu32(argv));		/* uid */
457 	cred->cr_gid = ntohl(svc_getu32(argv));		/* gid */
458 	slen = ntohl(svc_getu32(argv));			/* gids length */
459 	if (slen > 16 || (len -= (slen + 2)*4) < 0)
460 		goto badcred;
461 	cred->cr_group_info = groups_alloc(slen);
462 	if (cred->cr_group_info == NULL)
463 		return SVC_DROP;
464 	for (i = 0; i < slen; i++)
465 		GROUP_AT(cred->cr_group_info, i) = ntohl(svc_getu32(argv));
466 
467 	if (svc_getu32(argv) != RPC_AUTH_NULL || svc_getu32(argv) != 0) {
468 		*authp = rpc_autherr_badverf;
469 		return SVC_DENIED;
470 	}
471 
472 	/* Put NULL verifier */
473 	svc_putu32(resv, RPC_AUTH_NULL);
474 	svc_putu32(resv, 0);
475 
476 	return SVC_OK;
477 
478 badcred:
479 	*authp = rpc_autherr_badcred;
480 	return SVC_DENIED;
481 }
482 
483 static int
484 svcauth_unix_release(struct svc_rqst *rqstp)
485 {
486 	/* Verifier (such as it is) is already in place.
487 	 */
488 	if (rqstp->rq_client)
489 		auth_domain_put(rqstp->rq_client);
490 	rqstp->rq_client = NULL;
491 	if (rqstp->rq_cred.cr_group_info)
492 		put_group_info(rqstp->rq_cred.cr_group_info);
493 	rqstp->rq_cred.cr_group_info = NULL;
494 
495 	return 0;
496 }
497 
498 
499 struct auth_ops svcauth_unix = {
500 	.name		= "unix",
501 	.owner		= THIS_MODULE,
502 	.flavour	= RPC_AUTH_UNIX,
503 	.accept 	= svcauth_unix_accept,
504 	.release	= svcauth_unix_release,
505 	.domain_release	= svcauth_unix_domain_release,
506 	.set_client	= svcauth_unix_set_client,
507 };
508 
509