1/*
  2 * Copyright (c) 2008, Christoph Hellwig
  3 * All Rights Reserved.
  4 *
  5 * This program is free software; you can redistribute it and/or
  6 * modify it under the terms of the GNU General Public License as
  7 * published by the Free Software Foundation.
  8 *
  9 * This program is distributed in the hope that it would be useful,
 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12 * GNU General Public License for more details.
 13 *
 14 * You should have received a copy of the GNU General Public License
 15 * along with this program; if not, write the Free Software Foundation,
 16 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 17 */
 18#include "xfs.h"
 19#include "xfs_acl.h"
 20#include "xfs_attr.h"
 21#include "xfs_bmap_btree.h"
 
 
 22#include "xfs_inode.h"
 23#include "xfs_vnodeops.h"
 
 
 24#include "xfs_trace.h"
 25#include <linux/slab.h>
 26#include <linux/xattr.h>
 27#include <linux/posix_acl_xattr.h>
 
 28
 
 29
 30/*
 31 * Locking scheme:
 32 *  - all ACL updates are protected by inode->i_mutex, which is taken before
 33 *    calling into this file.
 34 */
 35
 36STATIC struct posix_acl *
 37xfs_acl_from_disk(struct xfs_acl *aclp)
 
 
 
 
 38{
 39	struct posix_acl_entry *acl_e;
 40	struct posix_acl *acl;
 41	struct xfs_acl_entry *ace;
 42	unsigned int count, i;
 43
 
 
 
 
 
 
 44	count = be32_to_cpu(aclp->acl_cnt);
 45	if (count > XFS_ACL_MAX_ENTRIES)
 
 
 46		return ERR_PTR(-EFSCORRUPTED);
 
 47
 48	acl = posix_acl_alloc(count, GFP_KERNEL);
 49	if (!acl)
 50		return ERR_PTR(-ENOMEM);
 51
 52	for (i = 0; i < count; i++) {
 53		acl_e = &acl->a_entries[i];
 54		ace = &aclp->acl_entry[i];
 55
 56		/*
 57		 * The tag is 32 bits on disk and 16 bits in core.
 58		 *
 59		 * Because every access to it goes through the core
 60		 * format first this is not a problem.
 61		 */
 62		acl_e->e_tag = be32_to_cpu(ace->ae_tag);
 63		acl_e->e_perm = be16_to_cpu(ace->ae_perm);
 64
 65		switch (acl_e->e_tag) {
 66		case ACL_USER:
 
 
 
 67		case ACL_GROUP:
 68			acl_e->e_id = be32_to_cpu(ace->ae_id);
 
 69			break;
 70		case ACL_USER_OBJ:
 71		case ACL_GROUP_OBJ:
 72		case ACL_MASK:
 73		case ACL_OTHER:
 74			acl_e->e_id = ACL_UNDEFINED_ID;
 75			break;
 76		default:
 77			goto fail;
 78		}
 79	}
 80	return acl;
 81
 82fail:
 83	posix_acl_release(acl);
 84	return ERR_PTR(-EINVAL);
 85}
 86
 87STATIC void
 88xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
 89{
 90	const struct posix_acl_entry *acl_e;
 91	struct xfs_acl_entry *ace;
 92	int i;
 93
 94	aclp->acl_cnt = cpu_to_be32(acl->a_count);
 95	for (i = 0; i < acl->a_count; i++) {
 96		ace = &aclp->acl_entry[i];
 97		acl_e = &acl->a_entries[i];
 98
 99		ace->ae_tag = cpu_to_be32(acl_e->e_tag);
100		ace->ae_id = cpu_to_be32(acl_e->e_id);
 
 
 
 
 
 
 
 
 
 
 
 
 
101		ace->ae_perm = cpu_to_be16(acl_e->e_perm);
102	}
103}
104
105struct posix_acl *
106xfs_get_acl(struct inode *inode, int type)
107{
108	struct xfs_inode *ip = XFS_I(inode);
109	struct posix_acl *acl;
110	struct xfs_acl *xfs_acl;
111	int len = sizeof(struct xfs_acl);
112	unsigned char *ea_name;
113	int error;
114
115	acl = get_cached_acl(inode, type);
116	if (acl != ACL_NOT_CACHED)
117		return acl;
 
 
118
119	trace_xfs_get_acl(ip);
120
121	switch (type) {
122	case ACL_TYPE_ACCESS:
123		ea_name = SGI_ACL_FILE;
124		break;
125	case ACL_TYPE_DEFAULT:
126		ea_name = SGI_ACL_DEFAULT;
127		break;
128	default:
129		BUG();
130	}
 
131
132	/*
133	 * If we have a cached ACLs value just return it, not need to
134	 * go out to the disk.
135	 */
136
137	xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
138	if (!xfs_acl)
139		return ERR_PTR(-ENOMEM);
140
141	error = -xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
142							&len, ATTR_ROOT);
143	if (error) {
144		/*
145		 * If the attribute doesn't exist make sure we have a negative
146		 * cache entry, for any other error assume it is transient and
147		 * leave the cache entry as ACL_NOT_CACHED.
148		 */
149		if (error == -ENOATTR) {
150			acl = NULL;
151			goto out_update_cache;
152		}
153		goto out;
154	}
155
156	acl = xfs_acl_from_disk(xfs_acl);
157	if (IS_ERR(acl))
158		goto out;
159
160 out_update_cache:
161	set_cached_acl(inode, type, acl);
162 out:
163	kfree(xfs_acl);
164	return acl;
165}
166
167STATIC int
168xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
169{
170	struct xfs_inode *ip = XFS_I(inode);
171	unsigned char *ea_name;
172	int error;
173
174	if (S_ISLNK(inode->i_mode))
175		return -EOPNOTSUPP;
176
177	switch (type) {
178	case ACL_TYPE_ACCESS:
179		ea_name = SGI_ACL_FILE;
180		break;
181	case ACL_TYPE_DEFAULT:
182		if (!S_ISDIR(inode->i_mode))
183			return acl ? -EACCES : 0;
184		ea_name = SGI_ACL_DEFAULT;
185		break;
186	default:
187		return -EINVAL;
188	}
 
189
190	if (acl) {
191		struct xfs_acl *xfs_acl;
192		int len;
193
194		xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
195		if (!xfs_acl)
196			return -ENOMEM;
197
198		xfs_acl_to_disk(xfs_acl, acl);
199		len = sizeof(struct xfs_acl) -
200			(sizeof(struct xfs_acl_entry) *
201			 (XFS_ACL_MAX_ENTRIES - acl->a_count));
202
203		error = -xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
204				len, ATTR_ROOT);
205
206		kfree(xfs_acl);
207	} else {
208		/*
209		 * A NULL ACL argument means we want to remove the ACL.
210		 */
211		error = -xfs_attr_remove(ip, ea_name, ATTR_ROOT);
212
213		/*
214		 * If the attribute didn't exist to start with that's fine.
215		 */
216		if (error == -ENOATTR)
217			error = 0;
218	}
219
220	if (!error)
221		set_cached_acl(inode, type, acl);
222	return error;
223}
224
225static int
226xfs_set_mode(struct inode *inode, umode_t mode)
227{
228	int error = 0;
229
230	if (mode != inode->i_mode) {
231		struct iattr iattr;
232
233		iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
234		iattr.ia_mode = mode;
235		iattr.ia_ctime = current_fs_time(inode->i_sb);
236
237		error = -xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
238	}
239
240	return error;
241}
242
243static int
244xfs_acl_exists(struct inode *inode, unsigned char *name)
245{
246	int len = sizeof(struct xfs_acl);
247
248	return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
249			    ATTR_ROOT|ATTR_KERNOVAL) == 0);
250}
251
252int
253posix_acl_access_exists(struct inode *inode)
254{
255	return xfs_acl_exists(inode, SGI_ACL_FILE);
256}
257
258int
259posix_acl_default_exists(struct inode *inode)
260{
261	if (!S_ISDIR(inode->i_mode))
262		return 0;
263	return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
264}
265
266/*
267 * No need for i_mutex because the inode is not yet exposed to the VFS.
268 */
269int
270xfs_inherit_acl(struct inode *inode, struct posix_acl *acl)
271{
272	umode_t mode = inode->i_mode;
273	int error = 0, inherit = 0;
274
275	if (S_ISDIR(inode->i_mode)) {
276		error = xfs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
277		if (error)
278			goto out;
279	}
280
281	error = posix_acl_create(&acl, GFP_KERNEL, &mode);
282	if (error < 0)
283		return error;
284
285	/*
286	 * If posix_acl_create returns a positive value we need to
287	 * inherit a permission that can't be represented using the Unix
288	 * mode bits and we actually need to set an ACL.
289	 */
290	if (error > 0)
291		inherit = 1;
292
293	error = xfs_set_mode(inode, mode);
294	if (error)
295		goto out;
296
297	if (inherit)
298		error = xfs_set_acl(inode, ACL_TYPE_ACCESS, acl);
299
300out:
301	posix_acl_release(acl);
302	return error;
303}
304
305int
306xfs_acl_chmod(struct inode *inode)
307{
308	struct posix_acl *acl;
309	int error;
310
311	if (S_ISLNK(inode->i_mode))
312		return -EOPNOTSUPP;
313
314	acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
315	if (IS_ERR(acl) || !acl)
316		return PTR_ERR(acl);
317
318	error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
319	if (error)
320		return error;
321
322	error = xfs_set_acl(inode, ACL_TYPE_ACCESS, acl);
323	posix_acl_release(acl);
324	return error;
325}
326
327static int
328xfs_xattr_acl_get(struct dentry *dentry, const char *name,
329		void *value, size_t size, int type)
330{
331	struct posix_acl *acl;
332	int error;
333
334	acl = xfs_get_acl(dentry->d_inode, type);
335	if (IS_ERR(acl))
336		return PTR_ERR(acl);
337	if (acl == NULL)
338		return -ENODATA;
339
340	error = posix_acl_to_xattr(acl, value, size);
341	posix_acl_release(acl);
342
343	return error;
344}
345
346static int
347xfs_xattr_acl_set(struct dentry *dentry, const char *name,
348		const void *value, size_t size, int flags, int type)
349{
350	struct inode *inode = dentry->d_inode;
351	struct posix_acl *acl = NULL;
352	int error = 0;
 
353
354	if (flags & XATTR_CREATE)
355		return -EINVAL;
356	if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
357		return value ? -EACCES : 0;
358	if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
359		return -EPERM;
360
361	if (!value)
362		goto set_acl;
363
364	acl = posix_acl_from_xattr(value, size);
365	if (!acl) {
366		/*
367		 * acl_set_file(3) may request that we set default ACLs with
368		 * zero length -- defend (gracefully) against that here.
369		 */
370		goto out;
371	}
372	if (IS_ERR(acl)) {
373		error = PTR_ERR(acl);
374		goto out;
375	}
376
377	error = posix_acl_valid(acl);
378	if (error)
379		goto out_release;
380
381	error = -EINVAL;
382	if (acl->a_count > XFS_ACL_MAX_ENTRIES)
383		goto out_release;
384
385	if (type == ACL_TYPE_ACCESS) {
386		umode_t mode = inode->i_mode;
387		error = posix_acl_equiv_mode(acl, &mode);
388
389		if (error <= 0) {
390			posix_acl_release(acl);
391			acl = NULL;
392
393			if (error < 0)
394				return error;
395		}
396
397		error = xfs_set_mode(inode, mode);
398		if (error)
399			goto out_release;
 
400	}
401
402 set_acl:
403	error = xfs_set_acl(inode, type, acl);
404 out_release:
405	posix_acl_release(acl);
406 out:
 
 
 
 
407	return error;
408}
409
410const struct xattr_handler xfs_xattr_acl_access_handler = {
411	.prefix	= POSIX_ACL_XATTR_ACCESS,
412	.flags	= ACL_TYPE_ACCESS,
413	.get	= xfs_xattr_acl_get,
414	.set	= xfs_xattr_acl_set,
415};
416
417const struct xattr_handler xfs_xattr_acl_default_handler = {
418	.prefix	= POSIX_ACL_XATTR_DEFAULT,
419	.flags	= ACL_TYPE_DEFAULT,
420	.get	= xfs_xattr_acl_get,
421	.set	= xfs_xattr_acl_set,
422};
 
 

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (c) 2008, Christoph Hellwig
  4 * All Rights Reserved.
 
 
 
 
 
 
 
 
 
 
 
 
 
  5 */
  6#include "xfs.h"
  7#include "xfs_shared.h"
  8#include "xfs_format.h"
  9#include "xfs_log_format.h"
 10#include "xfs_trans_resv.h"
 11#include "xfs_mount.h"
 12#include "xfs_inode.h"
 13#include "xfs_da_format.h"
 14#include "xfs_da_btree.h"
 15#include "xfs_attr.h"
 16#include "xfs_trace.h"
 17#include "xfs_error.h"
 18#include "xfs_acl.h"
 19#include "xfs_trans.h"
 20#include "xfs_xattr.h"
 21
 22#include <linux/posix_acl_xattr.h>
 23
 24/*
 25 * Locking scheme:
 26 *  - all ACL updates are protected by inode->i_mutex, which is taken before
 27 *    calling into this file.
 28 */
 29
 30STATIC struct posix_acl *
 31xfs_acl_from_disk(
 32	struct xfs_mount	*mp,
 33	const struct xfs_acl	*aclp,
 34	int			len,
 35	int			max_entries)
 36{
 37	struct posix_acl_entry *acl_e;
 38	struct posix_acl *acl;
 39	const struct xfs_acl_entry *ace;
 40	unsigned int count, i;
 41
 42	if (len < sizeof(*aclp)) {
 43		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
 44				len);
 45		return ERR_PTR(-EFSCORRUPTED);
 46	}
 47
 48	count = be32_to_cpu(aclp->acl_cnt);
 49	if (count > max_entries || XFS_ACL_SIZE(count) != len) {
 50		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
 51				len);
 52		return ERR_PTR(-EFSCORRUPTED);
 53	}
 54
 55	acl = posix_acl_alloc(count, GFP_KERNEL);
 56	if (!acl)
 57		return ERR_PTR(-ENOMEM);
 58
 59	for (i = 0; i < count; i++) {
 60		acl_e = &acl->a_entries[i];
 61		ace = &aclp->acl_entry[i];
 62
 63		/*
 64		 * The tag is 32 bits on disk and 16 bits in core.
 65		 *
 66		 * Because every access to it goes through the core
 67		 * format first this is not a problem.
 68		 */
 69		acl_e->e_tag = be32_to_cpu(ace->ae_tag);
 70		acl_e->e_perm = be16_to_cpu(ace->ae_perm);
 71
 72		switch (acl_e->e_tag) {
 73		case ACL_USER:
 74			acl_e->e_uid = make_kuid(&init_user_ns,
 75						 be32_to_cpu(ace->ae_id));
 76			break;
 77		case ACL_GROUP:
 78			acl_e->e_gid = make_kgid(&init_user_ns,
 79						 be32_to_cpu(ace->ae_id));
 80			break;
 81		case ACL_USER_OBJ:
 82		case ACL_GROUP_OBJ:
 83		case ACL_MASK:
 84		case ACL_OTHER:
 
 85			break;
 86		default:
 87			goto fail;
 88		}
 89	}
 90	return acl;
 91
 92fail:
 93	posix_acl_release(acl);
 94	return ERR_PTR(-EINVAL);
 95}
 96
 97STATIC void
 98xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
 99{
100	const struct posix_acl_entry *acl_e;
101	struct xfs_acl_entry *ace;
102	int i;
103
104	aclp->acl_cnt = cpu_to_be32(acl->a_count);
105	for (i = 0; i < acl->a_count; i++) {
106		ace = &aclp->acl_entry[i];
107		acl_e = &acl->a_entries[i];
108
109		ace->ae_tag = cpu_to_be32(acl_e->e_tag);
110		switch (acl_e->e_tag) {
111		case ACL_USER:
112			ace->ae_id = cpu_to_be32(
113					from_kuid(&init_user_ns, acl_e->e_uid));
114			break;
115		case ACL_GROUP:
116			ace->ae_id = cpu_to_be32(
117					from_kgid(&init_user_ns, acl_e->e_gid));
118			break;
119		default:
120			ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
121			break;
122		}
123
124		ace->ae_perm = cpu_to_be16(acl_e->e_perm);
125	}
126}
127
128struct posix_acl *
129xfs_get_acl(struct inode *inode, int type, bool rcu)
130{
131	struct xfs_inode	*ip = XFS_I(inode);
132	struct xfs_mount	*mp = ip->i_mount;
133	struct posix_acl	*acl = NULL;
134	struct xfs_da_args	args = {
135		.dp		= ip,
136		.attr_filter	= XFS_ATTR_ROOT,
137		.valuelen	= XFS_ACL_MAX_SIZE(mp),
138	};
139	int			error;
140
141	if (rcu)
142		return ERR_PTR(-ECHILD);
143
144	trace_xfs_get_acl(ip);
145
146	switch (type) {
147	case ACL_TYPE_ACCESS:
148		args.name = SGI_ACL_FILE;
149		break;
150	case ACL_TYPE_DEFAULT:
151		args.name = SGI_ACL_DEFAULT;
152		break;
153	default:
154		BUG();
155	}
156	args.namelen = strlen(args.name);
157
158	/*
159	 * If the attribute doesn't exist make sure we have a negative cache
160	 * entry, for any other error assume it is transient.
161	 */
162	error = xfs_attr_get(&args);
163	if (!error) {
164		acl = xfs_acl_from_disk(mp, args.value, args.valuelen,
165					XFS_ACL_MAX_ENTRIES(mp));
166	} else if (error != -ENOATTR) {
167		acl = ERR_PTR(error);
 
 
 
 
 
 
 
 
 
 
 
 
168	}
169
170	kvfree(args.value);
 
 
 
 
 
 
 
171	return acl;
172}
173
174int
175__xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
176{
177	struct xfs_inode	*ip = XFS_I(inode);
178	struct xfs_da_args	args = {
179		.dp		= ip,
180		.attr_filter	= XFS_ATTR_ROOT,
181	};
182	int			error;
183
184	switch (type) {
185	case ACL_TYPE_ACCESS:
186		args.name = SGI_ACL_FILE;
187		break;
188	case ACL_TYPE_DEFAULT:
189		if (!S_ISDIR(inode->i_mode))
190			return acl ? -EACCES : 0;
191		args.name = SGI_ACL_DEFAULT;
192		break;
193	default:
194		return -EINVAL;
195	}
196	args.namelen = strlen(args.name);
197
198	if (acl) {
199		args.valuelen = XFS_ACL_SIZE(acl->a_count);
200		args.value = kvzalloc(args.valuelen, GFP_KERNEL);
201		if (!args.value)
 
 
202			return -ENOMEM;
203		xfs_acl_to_disk(args.value, acl);
204		error = xfs_attr_change(&args, XFS_ATTRUPDATE_UPSERT);
205		kvfree(args.value);
 
 
 
 
 
 
 
206	} else {
207		error = xfs_attr_change(&args, XFS_ATTRUPDATE_REMOVE);
 
 
 
 
208		/*
209		 * If the attribute didn't exist to start with that's fine.
210		 */
211		if (error == -ENOATTR)
212			error = 0;
213	}
214
215	if (!error)
216		set_cached_acl(inode, type, acl);
217	return error;
218}
219
220static int
221xfs_acl_set_mode(
222	struct inode		*inode,
223	umode_t			mode)
224{
225	struct xfs_inode	*ip = XFS_I(inode);
226	struct xfs_mount	*mp = ip->i_mount;
227	struct xfs_trans	*tp;
228	int			error;
 
 
 
 
 
 
 
 
 
 
 
 
 
229
230	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
231	if (error)
232		return error;
233
234	xfs_ilock(ip, XFS_ILOCK_EXCL);
235	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
236	inode->i_mode = mode;
237	inode_set_ctime_current(inode);
238	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
239
240	if (xfs_has_wsync(mp))
241		xfs_trans_set_sync(tp);
242	return xfs_trans_commit(tp);
 
 
 
 
 
 
 
 
 
 
 
 
 
243}
244
245int
246xfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
247	    struct posix_acl *acl, int type)
248{
249	umode_t mode;
250	bool set_mode = false;
251	int error = 0;
252	struct inode *inode = d_inode(dentry);
253
254	if (!acl)
 
 
 
 
 
 
 
255		goto set_acl;
256
257	error = -E2BIG;
258	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
259		return error;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
260
261	if (type == ACL_TYPE_ACCESS) {
262		error = posix_acl_update_mode(idmap, inode, &mode, &acl);
 
 
 
 
 
 
 
 
 
 
 
263		if (error)
264			return error;
265		set_mode = true;
266	}
267
268 set_acl:
269	/*
270	 * We set the mode after successfully updating the ACL xattr because the
271	 * xattr update can fail at ENOSPC and we don't want to change the mode
272	 * if the ACL update hasn't been applied.
273	 */
274	error =  __xfs_set_acl(inode, acl, type);
275	if (!error && set_mode && mode != inode->i_mode)
276		error = xfs_acl_set_mode(inode, mode);
277	return error;
278}
279
280/*
281 * Invalidate any cached ACLs if the user has bypassed the ACL interface.
282 * We don't validate the content whatsoever so it is caller responsibility to
283 * provide data in valid format and ensure i_mode is consistent.
284 */
285void
286xfs_forget_acl(
287	struct inode		*inode,
288	const char		*name)
289{
290	if (!strcmp(name, SGI_ACL_FILE))
291		forget_cached_acl(inode, ACL_TYPE_ACCESS);
292	else if (!strcmp(name, SGI_ACL_DEFAULT))
293		forget_cached_acl(inode, ACL_TYPE_DEFAULT);
294}