1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * linux/fs/ceph/acl.c
  4 *
  5 * Copyright (C) 2013 Guangliang Zhao, <lucienchao@gmail.com>
  6 */
  7
  8#include <linux/ceph/ceph_debug.h>
  9#include <linux/fs.h>
 10#include <linux/string.h>
 11#include <linux/xattr.h>
 12#include <linux/posix_acl_xattr.h>
 13#include <linux/posix_acl.h>
 14#include <linux/sched.h>
 15#include <linux/slab.h>
 16
 17#include "super.h"
 18
 19static inline void ceph_set_cached_acl(struct inode *inode,
 20					int type, struct posix_acl *acl)
 21{
 22	struct ceph_inode_info *ci = ceph_inode(inode);
 23
 24	spin_lock(&ci->i_ceph_lock);
 25	if (__ceph_caps_issued_mask_metric(ci, CEPH_CAP_XATTR_SHARED, 0))
 26		set_cached_acl(inode, type, acl);
 27	else
 28		forget_cached_acl(inode, type);
 29	spin_unlock(&ci->i_ceph_lock);
 30}
 31
 32struct posix_acl *ceph_get_acl(struct inode *inode, int type, bool rcu)
 33{
 34	int size;
 35	unsigned int retry_cnt = 0;
 36	const char *name;
 37	char *value = NULL;
 38	struct posix_acl *acl;
 39
 40	if (rcu)
 41		return ERR_PTR(-ECHILD);
 42
 43	switch (type) {
 44	case ACL_TYPE_ACCESS:
 45		name = XATTR_NAME_POSIX_ACL_ACCESS;
 46		break;
 47	case ACL_TYPE_DEFAULT:
 48		name = XATTR_NAME_POSIX_ACL_DEFAULT;
 49		break;
 50	default:
 51		BUG();
 52	}
 53
 54retry:
 55	size = __ceph_getxattr(inode, name, "", 0);
 56	if (size > 0) {
 57		value = kzalloc(size, GFP_NOFS);
 58		if (!value)
 59			return ERR_PTR(-ENOMEM);
 60		size = __ceph_getxattr(inode, name, value, size);
 61	}
 62
 63	if (size == -ERANGE && retry_cnt < 10) {
 64		retry_cnt++;
 65		kfree(value);
 66		value = NULL;
 67		goto retry;
 68	}
 69
 70	if (size > 0) {
 71		acl = posix_acl_from_xattr(&init_user_ns, value, size);
 72	} else if (size == -ENODATA || size == 0) {
 73		acl = NULL;
 74	} else {
 75		pr_err_ratelimited("get acl %llx.%llx failed, err=%d\n",
 76				   ceph_vinop(inode), size);
 77		acl = ERR_PTR(-EIO);
 78	}
 79
 80	kfree(value);
 81
 82	if (!IS_ERR(acl))
 83		ceph_set_cached_acl(inode, type, acl);
 84
 85	return acl;
 86}
 87
 88int ceph_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry,
 89		 struct posix_acl *acl, int type)
 90{
 91	int ret = 0, size = 0;
 92	const char *name = NULL;
 93	char *value = NULL;
 94	struct iattr newattrs;
 95	struct inode *inode = d_inode(dentry);
 96	struct timespec64 old_ctime = inode->i_ctime;
 97	umode_t new_mode = inode->i_mode, old_mode = inode->i_mode;
 98
 99	if (ceph_snap(inode) != CEPH_NOSNAP) {
100		ret = -EROFS;
101		goto out;
102	}
103
104	switch (type) {
105	case ACL_TYPE_ACCESS:
106		name = XATTR_NAME_POSIX_ACL_ACCESS;
107		if (acl) {
108			ret = posix_acl_update_mode(&init_user_ns, inode,
109						    &new_mode, &acl);
110			if (ret)
111				goto out;
112		}
113		break;
114	case ACL_TYPE_DEFAULT:
115		if (!S_ISDIR(inode->i_mode)) {
116			ret = acl ? -EINVAL : 0;
117			goto out;
118		}
119		name = XATTR_NAME_POSIX_ACL_DEFAULT;
120		break;
121	default:
122		ret = -EINVAL;
123		goto out;
124	}
125
126	if (acl) {
127		size = posix_acl_xattr_size(acl->a_count);
128		value = kmalloc(size, GFP_NOFS);
129		if (!value) {
130			ret = -ENOMEM;
131			goto out;
132		}
133
134		ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
135		if (ret < 0)
136			goto out_free;
137	}
138
139	if (new_mode != old_mode) {
140		newattrs.ia_ctime = current_time(inode);
141		newattrs.ia_mode = new_mode;
142		newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
143		ret = __ceph_setattr(inode, &newattrs);
144		if (ret)
145			goto out_free;
146	}
147
148	ret = __ceph_setxattr(inode, name, value, size, 0);
149	if (ret) {
150		if (new_mode != old_mode) {
151			newattrs.ia_ctime = old_ctime;
152			newattrs.ia_mode = old_mode;
153			newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
154			__ceph_setattr(inode, &newattrs);
155		}
156		goto out_free;
157	}
158
159	ceph_set_cached_acl(inode, type, acl);
160
161out_free:
162	kfree(value);
163out:
164	return ret;
165}
166
167int ceph_pre_init_acls(struct inode *dir, umode_t *mode,
168		       struct ceph_acl_sec_ctx *as_ctx)
169{
170	struct posix_acl *acl, *default_acl;
171	size_t val_size1 = 0, val_size2 = 0;
172	struct ceph_pagelist *pagelist = NULL;
173	void *tmp_buf = NULL;
174	int err;
175
176	err = posix_acl_create(dir, mode, &default_acl, &acl);
177	if (err)
178		return err;
179
180	if (acl) {
181		err = posix_acl_equiv_mode(acl, mode);
182		if (err < 0)
183			goto out_err;
184		if (err == 0) {
185			posix_acl_release(acl);
186			acl = NULL;
187		}
188	}
189
190	if (!default_acl && !acl)
191		return 0;
192
193	if (acl)
194		val_size1 = posix_acl_xattr_size(acl->a_count);
195	if (default_acl)
196		val_size2 = posix_acl_xattr_size(default_acl->a_count);
197
198	err = -ENOMEM;
199	tmp_buf = kmalloc(max(val_size1, val_size2), GFP_KERNEL);
200	if (!tmp_buf)
201		goto out_err;
202	pagelist = ceph_pagelist_alloc(GFP_KERNEL);
203	if (!pagelist)
204		goto out_err;
205
206	err = ceph_pagelist_reserve(pagelist, PAGE_SIZE);
207	if (err)
208		goto out_err;
209
210	ceph_pagelist_encode_32(pagelist, acl && default_acl ? 2 : 1);
211
212	if (acl) {
213		size_t len = strlen(XATTR_NAME_POSIX_ACL_ACCESS);
214		err = ceph_pagelist_reserve(pagelist, len + val_size1 + 8);
215		if (err)
216			goto out_err;
217		ceph_pagelist_encode_string(pagelist, XATTR_NAME_POSIX_ACL_ACCESS,
218					    len);
219		err = posix_acl_to_xattr(&init_user_ns, acl,
220					 tmp_buf, val_size1);
221		if (err < 0)
222			goto out_err;
223		ceph_pagelist_encode_32(pagelist, val_size1);
224		ceph_pagelist_append(pagelist, tmp_buf, val_size1);
225	}
226	if (default_acl) {
227		size_t len = strlen(XATTR_NAME_POSIX_ACL_DEFAULT);
228		err = ceph_pagelist_reserve(pagelist, len + val_size2 + 8);
229		if (err)
230			goto out_err;
231		ceph_pagelist_encode_string(pagelist,
232					  XATTR_NAME_POSIX_ACL_DEFAULT, len);
233		err = posix_acl_to_xattr(&init_user_ns, default_acl,
234					 tmp_buf, val_size2);
235		if (err < 0)
236			goto out_err;
237		ceph_pagelist_encode_32(pagelist, val_size2);
238		ceph_pagelist_append(pagelist, tmp_buf, val_size2);
239	}
240
241	kfree(tmp_buf);
242
243	as_ctx->acl = acl;
244	as_ctx->default_acl = default_acl;
245	as_ctx->pagelist = pagelist;
246	return 0;
247
248out_err:
249	posix_acl_release(acl);
250	posix_acl_release(default_acl);
251	kfree(tmp_buf);
252	if (pagelist)
253		ceph_pagelist_release(pagelist);
254	return err;
255}
256
257void ceph_init_inode_acls(struct inode *inode, struct ceph_acl_sec_ctx *as_ctx)
258{
259	if (!inode)
260		return;
261	ceph_set_cached_acl(inode, ACL_TYPE_ACCESS, as_ctx->acl);
262	ceph_set_cached_acl(inode, ACL_TYPE_DEFAULT, as_ctx->default_acl);
263}