fs/ceph/acl.c

   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
  19 static 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
  32 struct 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
  51 retry:
  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
  85 int 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
 157 out_free:
 158         kfree(value);
 159 out:
 160         return ret;
 161 }
 162
 163 int 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
 244 out_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
 253 void 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 }