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)
 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	switch (type) {
 41	case ACL_TYPE_ACCESS:
 42		name = XATTR_NAME_POSIX_ACL_ACCESS;
 43		break;
 44	case ACL_TYPE_DEFAULT:
 45		name = XATTR_NAME_POSIX_ACL_DEFAULT;
 46		break;
 47	default:
 48		BUG();
 49	}
 50
 51retry:
 52	size = __ceph_getxattr(inode, name, "", 0);
 53	if (size > 0) {
 54		value = kzalloc(size, GFP_NOFS);
 55		if (!value)
 56			return ERR_PTR(-ENOMEM);
 57		size = __ceph_getxattr(inode, name, value, size);
 58	}
 59
 60	if (size == -ERANGE && retry_cnt < 10) {
 61		retry_cnt++;
 62		kfree(value);
 63		value = NULL;
 64		goto retry;
 65	}
 66
 67	if (size > 0) {
 68		acl = posix_acl_from_xattr(&init_user_ns, value, size);
 69	} else if (size == -ENODATA || size == 0) {
 70		acl = NULL;
 71	} else {
 72		pr_err_ratelimited("get acl %llx.%llx failed, err=%d\n",
 73				   ceph_vinop(inode), size);
 74		acl = ERR_PTR(-EIO);
 75	}
 76
 77	kfree(value);
 78
 79	if (!IS_ERR(acl))
 80		ceph_set_cached_acl(inode, type, acl);
 81
 82	return acl;
 83}
 84
 85int ceph_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 86		 struct posix_acl *acl, int type)
 87{
 88	int ret = 0, size = 0;
 89	const char *name = NULL;
 90	char *value = NULL;
 91	struct iattr newattrs;
 92	struct timespec64 old_ctime = inode->i_ctime;
 93	umode_t new_mode = inode->i_mode, old_mode = inode->i_mode;
 94
 95	if (ceph_snap(inode) != CEPH_NOSNAP) {
 96		ret = -EROFS;
 97		goto out;
 98	}
 99
100	switch (type) {
101	case ACL_TYPE_ACCESS:
102		name = XATTR_NAME_POSIX_ACL_ACCESS;
103		if (acl) {
104			ret = posix_acl_update_mode(&init_user_ns, inode,
105						    &new_mode, &acl);
106			if (ret)
107				goto out;
108		}
109		break;
110	case ACL_TYPE_DEFAULT:
111		if (!S_ISDIR(inode->i_mode)) {
112			ret = acl ? -EINVAL : 0;
113			goto out;
114		}
115		name = XATTR_NAME_POSIX_ACL_DEFAULT;
116		break;
117	default:
118		ret = -EINVAL;
119		goto out;
120	}
121
122	if (acl) {
123		size = posix_acl_xattr_size(acl->a_count);
124		value = kmalloc(size, GFP_NOFS);
125		if (!value) {
126			ret = -ENOMEM;
127			goto out;
128		}
129
130		ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
131		if (ret < 0)
132			goto out_free;
133	}
134
135	if (new_mode != old_mode) {
136		newattrs.ia_ctime = current_time(inode);
137		newattrs.ia_mode = new_mode;
138		newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
139		ret = __ceph_setattr(inode, &newattrs);
140		if (ret)
141			goto out_free;
142	}
143
144	ret = __ceph_setxattr(inode, name, value, size, 0);
145	if (ret) {
146		if (new_mode != old_mode) {
147			newattrs.ia_ctime = old_ctime;
148			newattrs.ia_mode = old_mode;
149			newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
150			__ceph_setattr(inode, &newattrs);
151		}
152		goto out_free;
153	}
154
155	ceph_set_cached_acl(inode, type, acl);
156
157out_free:
158	kfree(value);
159out:
160	return ret;
161}
162
163int ceph_pre_init_acls(struct inode *dir, umode_t *mode,
164		       struct ceph_acl_sec_ctx *as_ctx)
165{
166	struct posix_acl *acl, *default_acl;
167	size_t val_size1 = 0, val_size2 = 0;
168	struct ceph_pagelist *pagelist = NULL;
169	void *tmp_buf = NULL;
170	int err;
171
172	err = posix_acl_create(dir, mode, &default_acl, &acl);
173	if (err)
174		return err;
175
176	if (acl) {
177		err = posix_acl_equiv_mode(acl, mode);
178		if (err < 0)
179			goto out_err;
180		if (err == 0) {
181			posix_acl_release(acl);
182			acl = NULL;
183		}
184	}
185
186	if (!default_acl && !acl)
187		return 0;
188
189	if (acl)
190		val_size1 = posix_acl_xattr_size(acl->a_count);
191	if (default_acl)
192		val_size2 = posix_acl_xattr_size(default_acl->a_count);
193
194	err = -ENOMEM;
195	tmp_buf = kmalloc(max(val_size1, val_size2), GFP_KERNEL);
196	if (!tmp_buf)
197		goto out_err;
198	pagelist = ceph_pagelist_alloc(GFP_KERNEL);
199	if (!pagelist)
200		goto out_err;
201
202	err = ceph_pagelist_reserve(pagelist, PAGE_SIZE);
203	if (err)
204		goto out_err;
205
206	ceph_pagelist_encode_32(pagelist, acl && default_acl ? 2 : 1);
207
208	if (acl) {
209		size_t len = strlen(XATTR_NAME_POSIX_ACL_ACCESS);
210		err = ceph_pagelist_reserve(pagelist, len + val_size1 + 8);
211		if (err)
212			goto out_err;
213		ceph_pagelist_encode_string(pagelist, XATTR_NAME_POSIX_ACL_ACCESS,
214					    len);
215		err = posix_acl_to_xattr(&init_user_ns, acl,
216					 tmp_buf, val_size1);
217		if (err < 0)
218			goto out_err;
219		ceph_pagelist_encode_32(pagelist, val_size1);
220		ceph_pagelist_append(pagelist, tmp_buf, val_size1);
221	}
222	if (default_acl) {
223		size_t len = strlen(XATTR_NAME_POSIX_ACL_DEFAULT);
224		err = ceph_pagelist_reserve(pagelist, len + val_size2 + 8);
225		if (err)
226			goto out_err;
227		ceph_pagelist_encode_string(pagelist,
228					  XATTR_NAME_POSIX_ACL_DEFAULT, len);
229		err = posix_acl_to_xattr(&init_user_ns, default_acl,
230					 tmp_buf, val_size2);
231		if (err < 0)
232			goto out_err;
233		ceph_pagelist_encode_32(pagelist, val_size2);
234		ceph_pagelist_append(pagelist, tmp_buf, val_size2);
235	}
236
237	kfree(tmp_buf);
238
239	as_ctx->acl = acl;
240	as_ctx->default_acl = default_acl;
241	as_ctx->pagelist = pagelist;
242	return 0;
243
244out_err:
245	posix_acl_release(acl);
246	posix_acl_release(default_acl);
247	kfree(tmp_buf);
248	if (pagelist)
249		ceph_pagelist_release(pagelist);
250	return err;
251}
252
253void ceph_init_inode_acls(struct inode *inode, struct ceph_acl_sec_ctx *as_ctx)
254{
255	if (!inode)
256		return;
257	ceph_set_cached_acl(inode, ACL_TYPE_ACCESS, as_ctx->acl);
258	ceph_set_cached_acl(inode, ACL_TYPE_DEFAULT, as_ctx->default_acl);
259}