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.h"
  25 #include "v9fs_vfs.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(&init_user_ns, 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                         ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
  64                 set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL);
  65                 set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
  66                 return 0;
  67         }
  68         /* get the default/access acl values and cache them */
  69         dacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_DEFAULT);
  70         pacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_ACCESS);
  71
  72         if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
  73                 set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
  74                 set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
  75         } else
  76                 retval = -EIO;
  77
  78         if (!IS_ERR(dacl))
  79                 posix_acl_release(dacl);
  80
  81         if (!IS_ERR(pacl))
  82                 posix_acl_release(pacl);
  83
  84         return retval;
  85 }
  86
  87 static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
  88 {
  89         struct posix_acl *acl;
  90         /*
  91          * 9p Always cache the acl value when
  92          * instantiating the inode (v9fs_inode_from_fid)
  93          */
  94         acl = get_cached_acl(inode, type);
  95         BUG_ON(acl == ACL_NOT_CACHED);
  96         return acl;
  97 }
  98
  99 struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type)
 100 {
 101         struct v9fs_session_info *v9ses;
 102
 103         v9ses = v9fs_inode2v9ses(inode);
 104         if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
 105                         ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
 106                 /*
 107                  * On access = client  and acl = on mode get the acl
 108                  * values from the server
 109                  */
 110                 return NULL;
 111         }
 112         return v9fs_get_cached_acl(inode, type);
 113
 114 }
 115
 116 static int v9fs_set_acl(struct dentry *dentry, int type, struct posix_acl *acl)
 117 {
 118         int retval;
 119         char *name;
 120         size_t size;
 121         void *buffer;
 122         struct inode *inode = dentry->d_inode;
 123
 124         set_cached_acl(inode, type, acl);
 125
 126         if (!acl)
 127                 return 0;
 128
 129         /* Set a setxattr request to server */
 130         size = posix_acl_xattr_size(acl->a_count);
 131         buffer = kmalloc(size, GFP_KERNEL);
 132         if (!buffer)
 133                 return -ENOMEM;
 134         retval = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
 135         if (retval < 0)
 136                 goto err_free_out;
 137         switch (type) {
 138         case ACL_TYPE_ACCESS:
 139                 name = POSIX_ACL_XATTR_ACCESS;
 140                 break;
 141         case ACL_TYPE_DEFAULT:
 142                 name = POSIX_ACL_XATTR_DEFAULT;
 143                 break;
 144         default:
 145                 BUG();
 146         }
 147         retval = v9fs_xattr_set(dentry, name, buffer, size, 0);
 148 err_free_out:
 149         kfree(buffer);
 150         return retval;
 151 }
 152
 153 int v9fs_acl_chmod(struct dentry *dentry)
 154 {
 155         int retval = 0;
 156         struct posix_acl *acl;
 157         struct inode *inode = dentry->d_inode;
 158
 159         if (S_ISLNK(inode->i_mode))
 160                 return -EOPNOTSUPP;
 161         acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
 162         if (acl) {
 163                 retval = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
 164                 if (retval)
 165                         return retval;
 166                 retval = v9fs_set_acl(dentry, ACL_TYPE_ACCESS, acl);
 167                 posix_acl_release(acl);
 168         }
 169         return retval;
 170 }
 171
 172 int v9fs_set_create_acl(struct dentry *dentry,
 173                         struct posix_acl **dpacl, struct posix_acl **pacl)
 174 {
 175         if (dentry) {
 176                 v9fs_set_acl(dentry, ACL_TYPE_DEFAULT, *dpacl);
 177                 v9fs_set_acl(dentry, ACL_TYPE_ACCESS, *pacl);
 178         }
 179         posix_acl_release(*dpacl);
 180         posix_acl_release(*pacl);
 181         *dpacl = *pacl = NULL;
 182         return 0;
 183 }
 184
 185 int v9fs_acl_mode(struct inode *dir, umode_t *modep,
 186                   struct posix_acl **dpacl, struct posix_acl **pacl)
 187 {
 188         int retval = 0;
 189         umode_t mode = *modep;
 190         struct posix_acl *acl = NULL;
 191
 192         if (!S_ISLNK(mode)) {
 193                 acl = v9fs_get_cached_acl(dir, ACL_TYPE_DEFAULT);
 194                 if (IS_ERR(acl))
 195                         return PTR_ERR(acl);
 196                 if (!acl)
 197                         mode &= ~current_umask();
 198         }
 199         if (acl) {
 200                 if (S_ISDIR(mode))
 201                         *dpacl = posix_acl_dup(acl);
 202                 retval = posix_acl_create(&acl, GFP_NOFS, &mode);
 203                 if (retval < 0)
 204                         return retval;
 205                 if (retval > 0)
 206                         *pacl = acl;
 207                 else
 208                         posix_acl_release(acl);
 209         }
 210         *modep  = mode;
 211         return 0;
 212 }
 213
 214 static int v9fs_remote_get_acl(struct dentry *dentry, const char *name,
 215                                void *buffer, size_t size, int type)
 216 {
 217         char *full_name;
 218
 219         switch (type) {
 220         case ACL_TYPE_ACCESS:
 221                 full_name =  POSIX_ACL_XATTR_ACCESS;
 222                 break;
 223         case ACL_TYPE_DEFAULT:
 224                 full_name = POSIX_ACL_XATTR_DEFAULT;
 225                 break;
 226         default:
 227                 BUG();
 228         }
 229         return v9fs_xattr_get(dentry, full_name, buffer, size);
 230 }
 231
 232 static int v9fs_xattr_get_acl(struct dentry *dentry, const char *name,
 233                               void *buffer, size_t size, int type)
 234 {
 235         struct v9fs_session_info *v9ses;
 236         struct posix_acl *acl;
 237         int error;
 238
 239         if (strcmp(name, "") != 0)
 240                 return -EINVAL;
 241
 242         v9ses = v9fs_dentry2v9ses(dentry);
 243         /*
 244          * We allow set/get/list of acl when access=client is not specified
 245          */
 246         if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
 247                 return v9fs_remote_get_acl(dentry, name, buffer, size, type);
 248
 249         acl = v9fs_get_cached_acl(dentry->d_inode, type);
 250         if (IS_ERR(acl))
 251                 return PTR_ERR(acl);
 252         if (acl == NULL)
 253                 return -ENODATA;
 254         error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
 255         posix_acl_release(acl);
 256
 257         return error;
 258 }
 259
 260 static int v9fs_remote_set_acl(struct dentry *dentry, const char *name,
 261                               const void *value, size_t size,
 262                               int flags, int type)
 263 {
 264         char *full_name;
 265
 266         switch (type) {
 267         case ACL_TYPE_ACCESS:
 268                 full_name =  POSIX_ACL_XATTR_ACCESS;
 269                 break;
 270         case ACL_TYPE_DEFAULT:
 271                 full_name = POSIX_ACL_XATTR_DEFAULT;
 272                 break;
 273         default:
 274                 BUG();
 275         }
 276         return v9fs_xattr_set(dentry, full_name, value, size, flags);
 277 }
 278
 279
 280 static int v9fs_xattr_set_acl(struct dentry *dentry, const char *name,
 281                               const void *value, size_t size,
 282                               int flags, int type)
 283 {
 284         int retval;
 285         struct posix_acl *acl;
 286         struct v9fs_session_info *v9ses;
 287         struct inode *inode = dentry->d_inode;
 288
 289         if (strcmp(name, "") != 0)
 290                 return -EINVAL;
 291
 292         v9ses = v9fs_dentry2v9ses(dentry);
 293         /*
 294          * set the attribute on the remote. Without even looking at the
 295          * xattr value. We leave it to the server to validate
 296          */
 297         if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
 298                 return v9fs_remote_set_acl(dentry, name,
 299                                            value, size, flags, type);
 300
 301         if (S_ISLNK(inode->i_mode))
 302                 return -EOPNOTSUPP;
 303         if (!inode_owner_or_capable(inode))
 304                 return -EPERM;
 305         if (value) {
 306                 /* update the cached acl value */
 307                 acl = posix_acl_from_xattr(&init_user_ns, value, size);
 308                 if (IS_ERR(acl))
 309                         return PTR_ERR(acl);
 310                 else if (acl) {
 311                         retval = posix_acl_valid(acl);
 312                         if (retval)
 313                                 goto err_out;
 314                 }
 315         } else
 316                 acl = NULL;
 317
 318         switch (type) {
 319         case ACL_TYPE_ACCESS:
 320                 name = POSIX_ACL_XATTR_ACCESS;
 321                 if (acl) {
 322                         umode_t mode = inode->i_mode;
 323                         retval = posix_acl_equiv_mode(acl, &mode);
 324                         if (retval < 0)
 325                                 goto err_out;
 326                         else {
 327                                 struct iattr iattr;
 328                                 if (retval == 0) {
 329                                         /*
 330                                          * ACL can be represented
 331                                          * by the mode bits. So don't
 332                                          * update ACL.
 333                                          */
 334                                         acl = NULL;
 335                                         value = NULL;
 336                                         size = 0;
 337                                 }
 338                                 /* Updte the mode bits */
 339                                 iattr.ia_mode = ((mode & S_IALLUGO) |
 340                                                  (inode->i_mode & ~S_IALLUGO));
 341                                 iattr.ia_valid = ATTR_MODE;
 342                                 /* FIXME should we update ctime ?
 343                                  * What is the following setxattr update the
 344                                  * mode ?
 345                                  */
 346                                 v9fs_vfs_setattr_dotl(dentry, &iattr);
 347                         }
 348                 }
 349                 break;
 350         case ACL_TYPE_DEFAULT:
 351                 name = POSIX_ACL_XATTR_DEFAULT;
 352                 if (!S_ISDIR(inode->i_mode)) {
 353                         retval = acl ? -EINVAL : 0;
 354                         goto err_out;
 355                 }
 356                 break;
 357         default:
 358                 BUG();
 359         }
 360         retval = v9fs_xattr_set(dentry, name, value, size, flags);
 361         if (!retval)
 362                 set_cached_acl(inode, type, acl);
 363 err_out:
 364         posix_acl_release(acl);
 365         return retval;
 366 }
 367
 368 const struct xattr_handler v9fs_xattr_acl_access_handler = {
 369         .prefix = POSIX_ACL_XATTR_ACCESS,
 370         .flags  = ACL_TYPE_ACCESS,
 371         .get    = v9fs_xattr_get_acl,
 372         .set    = v9fs_xattr_set_acl,
 373 };
 374
 375 const struct xattr_handler v9fs_xattr_acl_default_handler = {
 376         .prefix = POSIX_ACL_XATTR_DEFAULT,
 377         .flags  = ACL_TYPE_DEFAULT,
 378         .get    = v9fs_xattr_get_acl,
 379         .set    = v9fs_xattr_set_acl,
 380 };