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, 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
  54 retry:
  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
  88 int ceph_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
  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 timespec64 old_ctime = inode->i_ctime;
  96         umode_t new_mode = inode->i_mode, old_mode = inode->i_mode;
  97
  98         if (ceph_snap(inode) != CEPH_NOSNAP) {
  99                 ret = -EROFS;
 100                 goto out;
 101         }
 102
 103         switch (type) {
 104         case ACL_TYPE_ACCESS:
 105                 name = XATTR_NAME_POSIX_ACL_ACCESS;
 106                 if (acl) {
 107                         ret = posix_acl_update_mode(&init_user_ns, inode,
 108                                                     &new_mode, &acl);
 109                         if (ret)
 110                                 goto out;
 111                 }
 112                 break;
 113         case ACL_TYPE_DEFAULT:
 114                 if (!S_ISDIR(inode->i_mode)) {
 115                         ret = acl ? -EINVAL : 0;
 116                         goto out;
 117                 }
 118                 name = XATTR_NAME_POSIX_ACL_DEFAULT;
 119                 break;
 120         default:
 121                 ret = -EINVAL;
 122                 goto out;
 123         }
 124
 125         if (acl) {
 126                 size = posix_acl_xattr_size(acl->a_count);
 127                 value = kmalloc(size, GFP_NOFS);
 128                 if (!value) {
 129                         ret = -ENOMEM;
 130                         goto out;
 131                 }
 132
 133                 ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
 134                 if (ret < 0)
 135                         goto out_free;
 136         }
 137
 138         if (new_mode != old_mode) {
 139                 newattrs.ia_ctime = current_time(inode);
 140                 newattrs.ia_mode = new_mode;
 141                 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
 142                 ret = __ceph_setattr(inode, &newattrs);
 143                 if (ret)
 144                         goto out_free;
 145         }
 146
 147         ret = __ceph_setxattr(inode, name, value, size, 0);
 148         if (ret) {
 149                 if (new_mode != old_mode) {
 150                         newattrs.ia_ctime = old_ctime;
 151                         newattrs.ia_mode = old_mode;
 152                         newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
 153                         __ceph_setattr(inode, &newattrs);
 154                 }
 155                 goto out_free;
 156         }
 157
 158         ceph_set_cached_acl(inode, type, acl);
 159
 160 out_free:
 161         kfree(value);
 162 out:
 163         return ret;
 164 }
 165
 166 int ceph_pre_init_acls(struct inode *dir, umode_t *mode,
 167                        struct ceph_acl_sec_ctx *as_ctx)
 168 {
 169         struct posix_acl *acl, *default_acl;
 170         size_t val_size1 = 0, val_size2 = 0;
 171         struct ceph_pagelist *pagelist = NULL;
 172         void *tmp_buf = NULL;
 173         int err;
 174
 175         err = posix_acl_create(dir, mode, &default_acl, &acl);
 176         if (err)
 177                 return err;
 178
 179         if (acl) {
 180                 err = posix_acl_equiv_mode(acl, mode);
 181                 if (err < 0)
 182                         goto out_err;
 183                 if (err == 0) {
 184                         posix_acl_release(acl);
 185                         acl = NULL;
 186                 }
 187         }
 188
 189         if (!default_acl && !acl)
 190                 return 0;
 191
 192         if (acl)
 193                 val_size1 = posix_acl_xattr_size(acl->a_count);
 194         if (default_acl)
 195                 val_size2 = posix_acl_xattr_size(default_acl->a_count);
 196
 197         err = -ENOMEM;
 198         tmp_buf = kmalloc(max(val_size1, val_size2), GFP_KERNEL);
 199         if (!tmp_buf)
 200                 goto out_err;
 201         pagelist = ceph_pagelist_alloc(GFP_KERNEL);
 202         if (!pagelist)
 203                 goto out_err;
 204
 205         err = ceph_pagelist_reserve(pagelist, PAGE_SIZE);
 206         if (err)
 207                 goto out_err;
 208
 209         ceph_pagelist_encode_32(pagelist, acl && default_acl ? 2 : 1);
 210
 211         if (acl) {
 212                 size_t len = strlen(XATTR_NAME_POSIX_ACL_ACCESS);
 213                 err = ceph_pagelist_reserve(pagelist, len + val_size1 + 8);
 214                 if (err)
 215                         goto out_err;
 216                 ceph_pagelist_encode_string(pagelist, XATTR_NAME_POSIX_ACL_ACCESS,
 217                                             len);
 218                 err = posix_acl_to_xattr(&init_user_ns, acl,
 219                                          tmp_buf, val_size1);
 220                 if (err < 0)
 221                         goto out_err;
 222                 ceph_pagelist_encode_32(pagelist, val_size1);
 223                 ceph_pagelist_append(pagelist, tmp_buf, val_size1);
 224         }
 225         if (default_acl) {
 226                 size_t len = strlen(XATTR_NAME_POSIX_ACL_DEFAULT);
 227                 err = ceph_pagelist_reserve(pagelist, len + val_size2 + 8);
 228                 if (err)
 229                         goto out_err;
 230                 ceph_pagelist_encode_string(pagelist,
 231                                           XATTR_NAME_POSIX_ACL_DEFAULT, len);
 232                 err = posix_acl_to_xattr(&init_user_ns, default_acl,
 233                                          tmp_buf, val_size2);
 234                 if (err < 0)
 235                         goto out_err;
 236                 ceph_pagelist_encode_32(pagelist, val_size2);
 237                 ceph_pagelist_append(pagelist, tmp_buf, val_size2);
 238         }
 239
 240         kfree(tmp_buf);
 241
 242         as_ctx->acl = acl;
 243         as_ctx->default_acl = default_acl;
 244         as_ctx->pagelist = pagelist;
 245         return 0;
 246
 247 out_err:
 248         posix_acl_release(acl);
 249         posix_acl_release(default_acl);
 250         kfree(tmp_buf);
 251         if (pagelist)
 252                 ceph_pagelist_release(pagelist);
 253         return err;
 254 }
 255
 256 void ceph_init_inode_acls(struct inode *inode, struct ceph_acl_sec_ctx *as_ctx)
 257 {
 258         if (!inode)
 259                 return;
 260         ceph_set_cached_acl(inode, ACL_TYPE_ACCESS, as_ctx->acl);
 261         ceph_set_cached_acl(inode, ACL_TYPE_DEFAULT, as_ctx->default_acl);
 262 }