fs/9p/acl.c

   1 /*
   2  * Copyright IBM Corporation, 2010
   3  * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of version 2.1 of the GNU Lesser General Public License
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  12  *
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/fs.h>
  17 #include <net/9p/9p.h>
  18 #include <net/9p/client.h>
  19 #include <linux/slab.h>
  20 #include <linux/sched.h>
  21 #include <linux/posix_acl_xattr.h>
  22 #include "xattr.h"
  23 #include "acl.h"
  24 #include "v9fs_vfs.h"
  25 #include "v9fs.h"
  26
  27 static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name)
  28 {
  29         ssize_t size;
  30         void *value = NULL;
  31         struct posix_acl *acl = NULL;;
  32
  33         size = v9fs_fid_xattr_get(fid, name, NULL, 0);
  34         if (size > 0) {
  35                 value = kzalloc(size, GFP_NOFS);
  36                 if (!value)
  37                         return ERR_PTR(-ENOMEM);
  38                 size = v9fs_fid_xattr_get(fid, name, value, size);
  39                 if (size > 0) {
  40                         acl = posix_acl_from_xattr(value, size);
  41                         if (IS_ERR(acl))
  42                                 goto err_out;
  43                 }
  44         } else if (size == -ENODATA || size == 0 ||
  45                    size == -ENOSYS || size == -EOPNOTSUPP) {
  46                 acl = NULL;
  47         } else
  48                 acl = ERR_PTR(-EIO);
  49
  50 err_out:
  51         kfree(value);
  52         return acl;
  53 }
  54
  55 int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
  56 {
  57         int retval = 0;
  58         struct posix_acl *pacl, *dacl;
  59         struct v9fs_session_info *v9ses;
  60
  61         v9ses = v9fs_inode2v9ses(inode);
  62         if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) {
  63                 set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL);
  64                 set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
  65                 return 0;
  66         }
  67         /* get the default/access acl values and cache them */
  68         dacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_DEFAULT);
  69         pacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_ACCESS);
  70
  71         if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
  72                 set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
  73                 set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
  74                 posix_acl_release(dacl);
  75                 posix_acl_release(pacl);
  76         } else
  77                 retval = -EIO;
  78
  79         return retval;
  80 }
  81
  82 static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
  83 {
  84         struct posix_acl *acl;
  85         /*
  86          * 9p Always cache the acl value when
  87          * instantiating the inode (v9fs_inode_from_fid)
  88          */
  89         acl = get_cached_acl(inode, type);
  90         BUG_ON(acl == ACL_NOT_CACHED);
  91         return acl;
  92 }
  93
  94 int v9fs_check_acl(struct inode *inode, int mask)
  95 {
  96         struct posix_acl *acl;
  97         struct v9fs_session_info *v9ses;
  98
  99         v9ses = v9fs_inode2v9ses(inode);
 100         if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) {
 101                 /*
 102                  * On access = client mode get the acl
 103                  * values from the server
 104                  */
 105                 return 0;
 106         }
 107         acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
 108
 109         if (IS_ERR(acl))
 110                 return PTR_ERR(acl);
 111         if (acl) {
 112                 int error = posix_acl_permission(inode, acl, mask);
 113                 posix_acl_release(acl);
 114                 return error;
 115         }
 116         return -EAGAIN;
 117 }
 118
 119 static int v9fs_set_acl(struct dentry *dentry, int type, struct posix_acl *acl)
 120 {
 121         int retval;
 122         char *name;
 123         size_t size;
 124         void *buffer;
 125         struct inode *inode = dentry->d_inode;
 126
 127         set_cached_acl(inode, type, acl);
 128         /* Set a setxattr request to server */
 129         size = posix_acl_xattr_size(acl->a_count);
 130         buffer = kmalloc(size, GFP_KERNEL);
 131         if (!buffer)
 132                 return -ENOMEM;
 133         retval = posix_acl_to_xattr(acl, buffer, size);
 134         if (retval < 0)
 135                 goto err_free_out;
 136         switch (type) {
 137         case ACL_TYPE_ACCESS:
 138                 name = POSIX_ACL_XATTR_ACCESS;
 139                 break;
 140         case ACL_TYPE_DEFAULT:
 141                 name = POSIX_ACL_XATTR_DEFAULT;
 142                 break;
 143         default:
 144                 BUG();
 145         }
 146         retval = v9fs_xattr_set(dentry, name, buffer, size, 0);
 147 err_free_out:
 148         kfree(buffer);
 149         return retval;
 150 }
 151
 152 int v9fs_acl_chmod(struct dentry *dentry)
 153 {
 154         int retval = 0;
 155         struct posix_acl *acl, *clone;
 156         struct inode *inode = dentry->d_inode;
 157
 158         if (S_ISLNK(inode->i_mode))
 159                 return -EOPNOTSUPP;
 160         acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
 161         if (acl) {
 162                 clone = posix_acl_clone(acl, GFP_KERNEL);
 163                 posix_acl_release(acl);
 164                 if (!clone)
 165                         return -ENOMEM;
 166                 retval = posix_acl_chmod_masq(clone, inode->i_mode);
 167                 if (!retval)
 168                         retval = v9fs_set_acl(dentry, ACL_TYPE_ACCESS, clone);
 169                 posix_acl_release(clone);
 170         }
 171         return retval;
 172 }
 173
 174 int v9fs_set_create_acl(struct dentry *dentry,
 175                         struct posix_acl *dpacl, struct posix_acl *pacl)
 176 {
 177         if (dpacl)
 178                 v9fs_set_acl(dentry, ACL_TYPE_DEFAULT, dpacl);
 179         if (pacl)
 180                 v9fs_set_acl(dentry, ACL_TYPE_ACCESS, pacl);
 181         posix_acl_release(dpacl);
 182         posix_acl_release(pacl);
 183         return 0;
 184 }
 185
 186 int v9fs_acl_mode(struct inode *dir, mode_t *modep,
 187                   struct posix_acl **dpacl, struct posix_acl **pacl)
 188 {
 189         int retval = 0;
 190         mode_t mode = *modep;
 191         struct posix_acl *acl = NULL;
 192
 193         if (!S_ISLNK(mode)) {
 194                 acl = v9fs_get_cached_acl(dir, ACL_TYPE_DEFAULT);
 195                 if (IS_ERR(acl))
 196                         return PTR_ERR(acl);
 197                 if (!acl)
 198                         mode &= ~current_umask();
 199         }
 200         if (acl) {
 201                 struct posix_acl *clone;
 202
 203                 if (S_ISDIR(mode))
 204                         *dpacl = acl;
 205                 clone = posix_acl_clone(acl, GFP_NOFS);
 206                 retval = -ENOMEM;
 207                 if (!clone)
 208                         goto cleanup;
 209
 210                 retval = posix_acl_create_masq(clone, &mode);
 211                 if (retval < 0) {
 212                         posix_acl_release(clone);
 213                         goto cleanup;
 214                 }
 215                 if (retval > 0)
 216                         *pacl = clone;
 217         }
 218         *modep  = mode;
 219         return 0;
 220 cleanup:
 221         posix_acl_release(acl);
 222         return retval;
 223
 224 }
 225
 226 static int v9fs_remote_get_acl(struct dentry *dentry, const char *name,
 227                                void *buffer, size_t size, int type)
 228 {
 229         char *full_name;
 230
 231         switch (type) {
 232         case ACL_TYPE_ACCESS:
 233                 full_name =  POSIX_ACL_XATTR_ACCESS;
 234                 break;
 235         case ACL_TYPE_DEFAULT:
 236                 full_name = POSIX_ACL_XATTR_DEFAULT;
 237                 break;
 238         default:
 239                 BUG();
 240         }
 241         return v9fs_xattr_get(dentry, full_name, buffer, size);
 242 }
 243
 244 static int v9fs_xattr_get_acl(struct dentry *dentry, const char *name,
 245                               void *buffer, size_t size, int type)
 246 {
 247         struct v9fs_session_info *v9ses;
 248         struct posix_acl *acl;
 249         int error;
 250
 251         if (strcmp(name, "") != 0)
 252                 return -EINVAL;
 253
 254         v9ses = v9fs_inode2v9ses(dentry->d_inode);
 255         /*
 256          * We allow set/get/list of acl when access=client is not specified
 257          */
 258         if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
 259                 return v9fs_remote_get_acl(dentry, name, buffer, size, type);
 260
 261         acl = v9fs_get_cached_acl(dentry->d_inode, type);
 262         if (IS_ERR(acl))
 263                 return PTR_ERR(acl);
 264         if (acl == NULL)
 265                 return -ENODATA;
 266         error = posix_acl_to_xattr(acl, buffer, size);
 267         posix_acl_release(acl);
 268
 269         return error;
 270 }
 271
 272 static int v9fs_remote_set_acl(struct dentry *dentry, const char *name,
 273                               const void *value, size_t size,
 274                               int flags, int type)
 275 {
 276         char *full_name;
 277
 278         switch (type) {
 279         case ACL_TYPE_ACCESS:
 280                 full_name =  POSIX_ACL_XATTR_ACCESS;
 281                 break;
 282         case ACL_TYPE_DEFAULT:
 283                 full_name = POSIX_ACL_XATTR_DEFAULT;
 284                 break;
 285         default:
 286                 BUG();
 287         }
 288         return v9fs_xattr_set(dentry, full_name, value, size, flags);
 289 }
 290
 291
 292 static int v9fs_xattr_set_acl(struct dentry *dentry, const char *name,
 293                               const void *value, size_t size,
 294                               int flags, int type)
 295 {
 296         int retval;
 297         struct posix_acl *acl;
 298         struct v9fs_session_info *v9ses;
 299         struct inode *inode = dentry->d_inode;
 300
 301         if (strcmp(name, "") != 0)
 302                 return -EINVAL;
 303
 304         v9ses = v9fs_inode2v9ses(dentry->d_inode);
 305         /*
 306          * set the attribute on the remote. Without even looking at the
 307          * xattr value. We leave it to the server to validate
 308          */
 309         if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
 310                 return v9fs_remote_set_acl(dentry, name,
 311                                            value, size, flags, type);
 312
 313         if (S_ISLNK(inode->i_mode))
 314                 return -EOPNOTSUPP;
 315         if (!is_owner_or_cap(inode))
 316                 return -EPERM;
 317         if (value) {
 318                 /* update the cached acl value */
 319                 acl = posix_acl_from_xattr(value, size);
 320                 if (IS_ERR(acl))
 321                         return PTR_ERR(acl);
 322                 else if (acl) {
 323                         retval = posix_acl_valid(acl);
 324                         if (retval)
 325                                 goto err_out;
 326                 }
 327         } else
 328                 acl = NULL;
 329
 330         switch (type) {
 331         case ACL_TYPE_ACCESS:
 332                 name = POSIX_ACL_XATTR_ACCESS;
 333                 if (acl) {
 334                         mode_t mode = inode->i_mode;
 335                         retval = posix_acl_equiv_mode(acl, &mode);
 336                         if (retval < 0)
 337                                 goto err_out;
 338                         else {
 339                                 struct iattr iattr;
 340                                 if (retval == 0) {
 341                                         /*
 342                                          * ACL can be represented
 343                                          * by the mode bits. So don't
 344                                          * update ACL.
 345                                          */
 346                                         acl = NULL;
 347                                         value = NULL;
 348                                         size = 0;
 349                                 }
 350                                 /* Updte the mode bits */
 351                                 iattr.ia_mode = ((mode & S_IALLUGO) |
 352                                                  (inode->i_mode & ~S_IALLUGO));
 353                                 iattr.ia_valid = ATTR_MODE;
 354                                 /* FIXME should we update ctime ?
 355                                  * What is the following setxattr update the
 356                                  * mode ?
 357                                  */
 358                                 v9fs_vfs_setattr_dotl(dentry, &iattr);
 359                         }
 360                 }
 361                 break;
 362         case ACL_TYPE_DEFAULT:
 363                 name = POSIX_ACL_XATTR_DEFAULT;
 364                 if (!S_ISDIR(inode->i_mode)) {
 365                         retval = -EINVAL;
 366                         goto err_out;
 367                 }
 368                 break;
 369         default:
 370                 BUG();
 371         }
 372         retval = v9fs_xattr_set(dentry, name, value, size, flags);
 373         if (!retval)
 374                 set_cached_acl(inode, type, acl);
 375 err_out:
 376         posix_acl_release(acl);
 377         return retval;
 378 }
 379
 380 const struct xattr_handler v9fs_xattr_acl_access_handler = {
 381         .prefix = POSIX_ACL_XATTR_ACCESS,
 382         .flags  = ACL_TYPE_ACCESS,
 383         .get    = v9fs_xattr_get_acl,
 384         .set    = v9fs_xattr_set_acl,
 385 };
 386
 387 const struct xattr_handler v9fs_xattr_acl_default_handler = {
 388         .prefix = POSIX_ACL_XATTR_DEFAULT,
 389         .flags  = ACL_TYPE_DEFAULT,
 390         .get    = v9fs_xattr_get_acl,
 391         .set    = v9fs_xattr_set_acl,
 392 };