fs/9p/acl.c

   1 // SPDX-License-Identifier: LGPL-2.1
   2 /*
   3  * Copyright IBM Corporation, 2010
   4  * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/fs.h>
   9 #include <net/9p/9p.h>
  10 #include <net/9p/client.h>
  11 #include <linux/slab.h>
  12 #include <linux/sched.h>
  13 #include <linux/posix_acl_xattr.h>
  14 #include "xattr.h"
  15 #include "acl.h"
  16 #include "v9fs.h"
  17 #include "v9fs_vfs.h"
  18 #include "fid.h"
  19
  20 static struct posix_acl *v9fs_fid_get_acl(struct p9_fid *fid, const char *name)
  21 {
  22         ssize_t size;
  23         void *value = NULL;
  24         struct posix_acl *acl = NULL;
  25
  26         size = v9fs_fid_xattr_get(fid, name, NULL, 0);
  27         if (size < 0)
  28                 return ERR_PTR(size);
  29         if (size == 0)
  30                 return ERR_PTR(-ENODATA);
  31
  32         value = kzalloc(size, GFP_NOFS);
  33         if (!value)
  34                 return ERR_PTR(-ENOMEM);
  35
  36         size = v9fs_fid_xattr_get(fid, name, value, size);
  37         if (size < 0)
  38                 acl = ERR_PTR(size);
  39         else if (size == 0)
  40                 acl = ERR_PTR(-ENODATA);
  41         else
  42                 acl = posix_acl_from_xattr(&init_user_ns, value, size);
  43         kfree(value);
  44         return acl;
  45 }
  46
  47 static struct posix_acl *v9fs_acl_get(struct dentry *dentry, const char *name)
  48 {
  49         struct p9_fid *fid;
  50         struct posix_acl *acl = NULL;
  51
  52         fid = v9fs_fid_lookup(dentry);
  53         if (IS_ERR(fid))
  54                 return ERR_CAST(fid);
  55
  56         acl = v9fs_fid_get_acl(fid, name);
  57         p9_fid_put(fid);
  58         return acl;
  59 }
  60
  61 static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, const char *name)
  62 {
  63         int retval;
  64         struct posix_acl *acl = NULL;
  65
  66         acl = v9fs_fid_get_acl(fid, name);
  67         if (!IS_ERR(acl))
  68                 return acl;
  69
  70         retval = PTR_ERR(acl);
  71         if (retval == -ENODATA || retval == -ENOSYS || retval == -EOPNOTSUPP)
  72                 return NULL;
  73
  74         /* map everything else to -EIO */
  75         return ERR_PTR(-EIO);
  76 }
  77
  78 int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
  79 {
  80         int retval = 0;
  81         struct posix_acl *pacl, *dacl;
  82         struct v9fs_session_info *v9ses;
  83
  84         v9ses = v9fs_inode2v9ses(inode);
  85         if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
  86                         ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
  87                 set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL);
  88                 set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
  89                 return 0;
  90         }
  91         /* get the default/access acl values and cache them */
  92         dacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_DEFAULT);
  93         pacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_ACCESS);
  94
  95         if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
  96                 set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
  97                 set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
  98         } else
  99                 retval = -EIO;
 100
 101         if (!IS_ERR(dacl))
 102                 posix_acl_release(dacl);
 103
 104         if (!IS_ERR(pacl))
 105                 posix_acl_release(pacl);
 106
 107         return retval;
 108 }
 109
 110 static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
 111 {
 112         struct posix_acl *acl;
 113         /*
 114          * 9p Always cache the acl value when
 115          * instantiating the inode (v9fs_inode_from_fid)
 116          */
 117         acl = get_cached_acl(inode, type);
 118         BUG_ON(is_uncached_acl(acl));
 119         return acl;
 120 }
 121
 122 struct posix_acl *v9fs_iop_get_inode_acl(struct inode *inode, int type, bool rcu)
 123 {
 124         struct v9fs_session_info *v9ses;
 125
 126         if (rcu)
 127                 return ERR_PTR(-ECHILD);
 128
 129         v9ses = v9fs_inode2v9ses(inode);
 130         if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
 131                         ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
 132                 /*
 133                  * On access = client  and acl = on mode get the acl
 134                  * values from the server
 135                  */
 136                 return NULL;
 137         }
 138         return v9fs_get_cached_acl(inode, type);
 139
 140 }
 141
 142 struct posix_acl *v9fs_iop_get_acl(struct mnt_idmap *idmap,
 143                                    struct dentry *dentry, int type)
 144 {
 145         struct v9fs_session_info *v9ses;
 146
 147         v9ses = v9fs_dentry2v9ses(dentry);
 148         /* We allow set/get/list of acl when access=client is not specified. */
 149         if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
 150                 return v9fs_acl_get(dentry, posix_acl_xattr_name(type));
 151         return v9fs_get_cached_acl(d_inode(dentry), type);
 152 }
 153
 154 int v9fs_iop_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 155                      struct posix_acl *acl, int type)
 156 {
 157         int retval;
 158         size_t size = 0;
 159         void *value = NULL;
 160         const char *acl_name;
 161         struct v9fs_session_info *v9ses;
 162         struct inode *inode = d_inode(dentry);
 163
 164         if (acl) {
 165                 retval = posix_acl_valid(inode->i_sb->s_user_ns, acl);
 166                 if (retval)
 167                         goto err_out;
 168
 169                 size = posix_acl_xattr_size(acl->a_count);
 170
 171                 value = kzalloc(size, GFP_NOFS);
 172                 if (!value) {
 173                         retval = -ENOMEM;
 174                         goto err_out;
 175                 }
 176
 177                 retval = posix_acl_to_xattr(&init_user_ns, acl, value, size);
 178                 if (retval < 0)
 179                         goto err_out;
 180         }
 181
 182         /*
 183          * set the attribute on the remote. Without even looking at the
 184          * xattr value. We leave it to the server to validate
 185          */
 186         acl_name = posix_acl_xattr_name(type);
 187         v9ses = v9fs_dentry2v9ses(dentry);
 188         if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) {
 189                 retval = v9fs_xattr_set(dentry, acl_name, value, size, 0);
 190                 goto err_out;
 191         }
 192
 193         if (S_ISLNK(inode->i_mode)) {
 194                 retval = -EOPNOTSUPP;
 195                 goto err_out;
 196         }
 197
 198         if (!inode_owner_or_capable(&nop_mnt_idmap, inode)) {
 199                 retval = -EPERM;
 200                 goto err_out;
 201         }
 202
 203         switch (type) {
 204         case ACL_TYPE_ACCESS:
 205                 if (acl) {
 206                         struct iattr iattr = {};
 207                         struct posix_acl *acl_mode = acl;
 208
 209                         retval = posix_acl_update_mode(&nop_mnt_idmap, inode,
 210                                                        &iattr.ia_mode,
 211                                                        &acl_mode);
 212                         if (retval)
 213                                 goto err_out;
 214                         if (!acl_mode) {
 215                                 /*
 216                                  * ACL can be represented by the mode bits.
 217                                  * So don't update ACL below.
 218                                  */
 219                                 kfree(value);
 220                                 value = NULL;
 221                                 size = 0;
 222                         }
 223                         iattr.ia_valid = ATTR_MODE;
 224                         /*
 225                          * FIXME should we update ctime ?
 226                          * What is the following setxattr update the mode ?
 227                          */
 228                         v9fs_vfs_setattr_dotl(&nop_mnt_idmap, dentry, &iattr);
 229                 }
 230                 break;
 231         case ACL_TYPE_DEFAULT:
 232                 if (!S_ISDIR(inode->i_mode)) {
 233                         retval = acl ? -EINVAL : 0;
 234                         goto err_out;
 235                 }
 236                 break;
 237         }
 238
 239         retval = v9fs_xattr_set(dentry, acl_name, value, size, 0);
 240         if (!retval)
 241                 set_cached_acl(inode, type, acl);
 242
 243 err_out:
 244         kfree(value);
 245         return retval;
 246 }
 247
 248 static int v9fs_set_acl(struct p9_fid *fid, int type, struct posix_acl *acl)
 249 {
 250         int retval;
 251         char *name;
 252         size_t size;
 253         void *buffer;
 254
 255         if (!acl)
 256                 return 0;
 257
 258         /* Set a setxattr request to server */
 259         size = posix_acl_xattr_size(acl->a_count);
 260         buffer = kmalloc(size, GFP_KERNEL);
 261         if (!buffer)
 262                 return -ENOMEM;
 263         retval = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
 264         if (retval < 0)
 265                 goto err_free_out;
 266         switch (type) {
 267         case ACL_TYPE_ACCESS:
 268                 name = XATTR_NAME_POSIX_ACL_ACCESS;
 269                 break;
 270         case ACL_TYPE_DEFAULT:
 271                 name = XATTR_NAME_POSIX_ACL_DEFAULT;
 272                 break;
 273         default:
 274                 BUG();
 275         }
 276         retval = v9fs_fid_xattr_set(fid, name, buffer, size, 0);
 277 err_free_out:
 278         kfree(buffer);
 279         return retval;
 280 }
 281
 282 int v9fs_acl_chmod(struct inode *inode, struct p9_fid *fid)
 283 {
 284         int retval = 0;
 285         struct posix_acl *acl;
 286
 287         if (S_ISLNK(inode->i_mode))
 288                 return -EOPNOTSUPP;
 289         acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
 290         if (acl) {
 291                 retval = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
 292                 if (retval)
 293                         return retval;
 294                 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
 295                 retval = v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
 296                 posix_acl_release(acl);
 297         }
 298         return retval;
 299 }
 300
 301 int v9fs_set_create_acl(struct inode *inode, struct p9_fid *fid,
 302                         struct posix_acl *dacl, struct posix_acl *acl)
 303 {
 304         set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
 305         set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
 306         v9fs_set_acl(fid, ACL_TYPE_DEFAULT, dacl);
 307         v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
 308         return 0;
 309 }
 310
 311 void v9fs_put_acl(struct posix_acl *dacl,
 312                   struct posix_acl *acl)
 313 {
 314         posix_acl_release(dacl);
 315         posix_acl_release(acl);
 316 }
 317
 318 int v9fs_acl_mode(struct inode *dir, umode_t *modep,
 319                   struct posix_acl **dpacl, struct posix_acl **pacl)
 320 {
 321         int retval = 0;
 322         umode_t mode = *modep;
 323         struct posix_acl *acl = NULL;
 324
 325         if (!S_ISLNK(mode)) {
 326                 acl = v9fs_get_cached_acl(dir, ACL_TYPE_DEFAULT);
 327                 if (IS_ERR(acl))
 328                         return PTR_ERR(acl);
 329                 if (!acl)
 330                         mode &= ~current_umask();
 331         }
 332         if (acl) {
 333                 if (S_ISDIR(mode))
 334                         *dpacl = posix_acl_dup(acl);
 335                 retval = __posix_acl_create(&acl, GFP_NOFS, &mode);
 336                 if (retval < 0)
 337                         return retval;
 338                 if (retval > 0)
 339                         *pacl = acl;
 340                 else
 341                         posix_acl_release(acl);
 342         }
 343         *modep  = mode;
 344         return 0;
 345 }