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(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 inode *inode, struct posix_acl *acl, int type)
  86 {
  87         int ret = 0, size = 0;
  88         const char *name = NULL;
  89         char *value = NULL;
  90         struct iattr newattrs;
  91         struct timespec64 old_ctime = inode->i_ctime;
  92         umode_t new_mode = inode->i_mode, old_mode = inode->i_mode;
  93
  94         if (ceph_snap(inode) != CEPH_NOSNAP) {
  95                 ret = -EROFS;
  96                 goto out;
  97         }
  98
  99         switch (type) {
 100         case ACL_TYPE_ACCESS:
 101                 name = XATTR_NAME_POSIX_ACL_ACCESS;
 102                 if (acl) {
 103                         ret = posix_acl_update_mode(inode, &new_mode, &acl);
 104                         if (ret)
 105                                 goto out;
 106                 }
 107                 break;
 108         case ACL_TYPE_DEFAULT:
 109                 if (!S_ISDIR(inode->i_mode)) {
 110                         ret = acl ? -EINVAL : 0;
 111                         goto out;
 112                 }
 113                 name = XATTR_NAME_POSIX_ACL_DEFAULT;
 114                 break;
 115         default:
 116                 ret = -EINVAL;
 117                 goto out;
 118         }
 119
 120         if (acl) {
 121                 size = posix_acl_xattr_size(acl->a_count);
 122                 value = kmalloc(size, GFP_NOFS);
 123                 if (!value) {
 124                         ret = -ENOMEM;
 125                         goto out;
 126                 }
 127
 128                 ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
 129                 if (ret < 0)
 130                         goto out_free;
 131         }
 132
 133         if (new_mode != old_mode) {
 134                 newattrs.ia_ctime = current_time(inode);
 135                 newattrs.ia_mode = new_mode;
 136                 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
 137                 ret = __ceph_setattr(inode, &newattrs);
 138                 if (ret)
 139                         goto out_free;
 140         }
 141
 142         ret = __ceph_setxattr(inode, name, value, size, 0);
 143         if (ret) {
 144                 if (new_mode != old_mode) {
 145                         newattrs.ia_ctime = old_ctime;
 146                         newattrs.ia_mode = old_mode;
 147                         newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
 148                         __ceph_setattr(inode, &newattrs);
 149                 }
 150                 goto out_free;
 151         }
 152
 153         ceph_set_cached_acl(inode, type, acl);
 154
 155 out_free:
 156         kfree(value);
 157 out:
 158         return ret;
 159 }
 160
 161 int ceph_pre_init_acls(struct inode *dir, umode_t *mode,
 162                        struct ceph_acl_sec_ctx *as_ctx)
 163 {
 164         struct posix_acl *acl, *default_acl;
 165         size_t val_size1 = 0, val_size2 = 0;
 166         struct ceph_pagelist *pagelist = NULL;
 167         void *tmp_buf = NULL;
 168         int err;
 169
 170         err = posix_acl_create(dir, mode, &default_acl, &acl);
 171         if (err)
 172                 return err;
 173
 174         if (acl) {
 175                 err = posix_acl_equiv_mode(acl, mode);
 176                 if (err < 0)
 177                         goto out_err;
 178                 if (err == 0) {
 179                         posix_acl_release(acl);
 180                         acl = NULL;
 181                 }
 182         }
 183
 184         if (!default_acl && !acl)
 185                 return 0;
 186
 187         if (acl)
 188                 val_size1 = posix_acl_xattr_size(acl->a_count);
 189         if (default_acl)
 190                 val_size2 = posix_acl_xattr_size(default_acl->a_count);
 191
 192         err = -ENOMEM;
 193         tmp_buf = kmalloc(max(val_size1, val_size2), GFP_KERNEL);
 194         if (!tmp_buf)
 195                 goto out_err;
 196         pagelist = ceph_pagelist_alloc(GFP_KERNEL);
 197         if (!pagelist)
 198                 goto out_err;
 199
 200         err = ceph_pagelist_reserve(pagelist, PAGE_SIZE);
 201         if (err)
 202                 goto out_err;
 203
 204         ceph_pagelist_encode_32(pagelist, acl && default_acl ? 2 : 1);
 205
 206         if (acl) {
 207                 size_t len = strlen(XATTR_NAME_POSIX_ACL_ACCESS);
 208                 err = ceph_pagelist_reserve(pagelist, len + val_size1 + 8);
 209                 if (err)
 210                         goto out_err;
 211                 ceph_pagelist_encode_string(pagelist, XATTR_NAME_POSIX_ACL_ACCESS,
 212                                             len);
 213                 err = posix_acl_to_xattr(&init_user_ns, acl,
 214                                          tmp_buf, val_size1);
 215                 if (err < 0)
 216                         goto out_err;
 217                 ceph_pagelist_encode_32(pagelist, val_size1);
 218                 ceph_pagelist_append(pagelist, tmp_buf, val_size1);
 219         }
 220         if (default_acl) {
 221                 size_t len = strlen(XATTR_NAME_POSIX_ACL_DEFAULT);
 222                 err = ceph_pagelist_reserve(pagelist, len + val_size2 + 8);
 223                 if (err)
 224                         goto out_err;
 225                 err = ceph_pagelist_encode_string(pagelist,
 226                                                   XATTR_NAME_POSIX_ACL_DEFAULT, len);
 227                 err = posix_acl_to_xattr(&init_user_ns, default_acl,
 228                                          tmp_buf, val_size2);
 229                 if (err < 0)
 230                         goto out_err;
 231                 ceph_pagelist_encode_32(pagelist, val_size2);
 232                 ceph_pagelist_append(pagelist, tmp_buf, val_size2);
 233         }
 234
 235         kfree(tmp_buf);
 236
 237         as_ctx->acl = acl;
 238         as_ctx->default_acl = default_acl;
 239         as_ctx->pagelist = pagelist;
 240         return 0;
 241
 242 out_err:
 243         posix_acl_release(acl);
 244         posix_acl_release(default_acl);
 245         kfree(tmp_buf);
 246         if (pagelist)
 247                 ceph_pagelist_release(pagelist);
 248         return err;
 249 }
 250
 251 void ceph_init_inode_acls(struct inode *inode, struct ceph_acl_sec_ctx *as_ctx)
 252 {
 253         if (!inode)
 254                 return;
 255         ceph_set_cached_acl(inode, ACL_TYPE_ACCESS, as_ctx->acl);
 256         ceph_set_cached_acl(inode, ACL_TYPE_DEFAULT, as_ctx->default_acl);
 257 }