fs/cifs/xattr.c

   1 /*
   2  *   fs/cifs/xattr.c
   3  *
   4  *   Copyright (c) International Business Machines  Corp., 2003, 2007
   5  *   Author(s): Steve French (sfrench@us.ibm.com)
   6  *
   7  *   This library is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU Lesser General Public License as published
   9  *   by the Free Software Foundation; either version 2.1 of the License, or
  10  *   (at your option) any later version.
  11  *
  12  *   This library is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  15  *   the GNU Lesser General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU Lesser General Public License
  18  *   along with this library; if not, write to the Free Software
  19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <linux/fs.h>
  23 #include <linux/posix_acl_xattr.h>
  24 #include <linux/slab.h>
  25 #include <linux/xattr.h>
  26 #include "cifsfs.h"
  27 #include "cifspdu.h"
  28 #include "cifsglob.h"
  29 #include "cifsproto.h"
  30 #include "cifs_debug.h"
  31 #include "cifs_fs_sb.h"
  32 #include "cifs_unicode.h"
  33
  34 #define MAX_EA_VALUE_SIZE 65535
  35 #define CIFS_XATTR_CIFS_ACL "system.cifs_acl"
  36
  37 /* BB need to add server (Samba e.g) support for security and trusted prefix */
  38
  39 enum { XATTR_USER, XATTR_CIFS_ACL, XATTR_ACL_ACCESS, XATTR_ACL_DEFAULT };
  40
  41 static int cifs_xattr_set(const struct xattr_handler *handler,
  42                           struct dentry *dentry, struct inode *inode,
  43                           const char *name, const void *value,
  44                           size_t size, int flags)
  45 {
  46         int rc = -EOPNOTSUPP;
  47         unsigned int xid;
  48         struct super_block *sb = dentry->d_sb;
  49         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
  50         struct tcon_link *tlink;
  51         struct cifs_tcon *pTcon;
  52         char *full_path;
  53
  54         tlink = cifs_sb_tlink(cifs_sb);
  55         if (IS_ERR(tlink))
  56                 return PTR_ERR(tlink);
  57         pTcon = tlink_tcon(tlink);
  58
  59         xid = get_xid();
  60
  61         full_path = build_path_from_dentry(dentry);
  62         if (full_path == NULL) {
  63                 rc = -ENOMEM;
  64                 goto out;
  65         }
  66         /* return dos attributes as pseudo xattr */
  67         /* return alt name if available as pseudo attr */
  68
  69         /* if proc/fs/cifs/streamstoxattr is set then
  70                 search server for EAs or streams to
  71                 returns as xattrs */
  72         if (size > MAX_EA_VALUE_SIZE) {
  73                 cifs_dbg(FYI, "size of EA value too large\n");
  74                 rc = -EOPNOTSUPP;
  75                 goto out;
  76         }
  77
  78         switch (handler->flags) {
  79         case XATTR_USER:
  80                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
  81                         goto out;
  82
  83                 if (pTcon->ses->server->ops->set_EA)
  84                         rc = pTcon->ses->server->ops->set_EA(xid, pTcon,
  85                                 full_path, name, value, (__u16)size,
  86                                 cifs_sb->local_nls, cifs_remap(cifs_sb));
  87                 break;
  88
  89         case XATTR_CIFS_ACL: {
  90 #ifdef CONFIG_CIFS_ACL
  91                 struct cifs_ntsd *pacl;
  92
  93                 if (!value)
  94                         goto out;
  95                 pacl = kmalloc(size, GFP_KERNEL);
  96                 if (!pacl) {
  97                         rc = -ENOMEM;
  98                 } else {
  99                         memcpy(pacl, value, size);
 100                         if (value &&
 101                             pTcon->ses->server->ops->set_acl)
 102                                 rc = pTcon->ses->server->ops->set_acl(pacl,
 103                                                 size, inode,
 104                                                 full_path, CIFS_ACL_DACL);
 105                         else
 106                                 rc = -EOPNOTSUPP;
 107                         if (rc == 0) /* force revalidate of the inode */
 108                                 CIFS_I(inode)->time = 0;
 109                         kfree(pacl);
 110                 }
 111 #endif /* CONFIG_CIFS_ACL */
 112                 break;
 113         }
 114
 115         case XATTR_ACL_ACCESS:
 116 #ifdef CONFIG_CIFS_POSIX
 117                 if (!value)
 118                         goto out;
 119                 if (sb->s_flags & MS_POSIXACL)
 120                         rc = CIFSSMBSetPosixACL(xid, pTcon, full_path,
 121                                 value, (const int)size,
 122                                 ACL_TYPE_ACCESS, cifs_sb->local_nls,
 123                                 cifs_remap(cifs_sb));
 124 #endif  /* CONFIG_CIFS_POSIX */
 125                 break;
 126
 127         case XATTR_ACL_DEFAULT:
 128 #ifdef CONFIG_CIFS_POSIX
 129                 if (!value)
 130                         goto out;
 131                 if (sb->s_flags & MS_POSIXACL)
 132                         rc = CIFSSMBSetPosixACL(xid, pTcon, full_path,
 133                                 value, (const int)size,
 134                                 ACL_TYPE_DEFAULT, cifs_sb->local_nls,
 135                                 cifs_remap(cifs_sb));
 136 #endif  /* CONFIG_CIFS_POSIX */
 137                 break;
 138         }
 139
 140 out:
 141         kfree(full_path);
 142         free_xid(xid);
 143         cifs_put_tlink(tlink);
 144         return rc;
 145 }
 146
 147 static int cifs_xattr_get(const struct xattr_handler *handler,
 148                           struct dentry *dentry, struct inode *inode,
 149                           const char *name, void *value, size_t size)
 150 {
 151         ssize_t rc = -EOPNOTSUPP;
 152         unsigned int xid;
 153         struct super_block *sb = dentry->d_sb;
 154         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 155         struct tcon_link *tlink;
 156         struct cifs_tcon *pTcon;
 157         char *full_path;
 158
 159         tlink = cifs_sb_tlink(cifs_sb);
 160         if (IS_ERR(tlink))
 161                 return PTR_ERR(tlink);
 162         pTcon = tlink_tcon(tlink);
 163
 164         xid = get_xid();
 165
 166         full_path = build_path_from_dentry(dentry);
 167         if (full_path == NULL) {
 168                 rc = -ENOMEM;
 169                 goto out;
 170         }
 171         /* return dos attributes as pseudo xattr */
 172         /* return alt name if available as pseudo attr */
 173         switch (handler->flags) {
 174         case XATTR_USER:
 175                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
 176                         goto out;
 177
 178                 if (pTcon->ses->server->ops->query_all_EAs)
 179                         rc = pTcon->ses->server->ops->query_all_EAs(xid, pTcon,
 180                                 full_path, name, value, size,
 181                                 cifs_sb->local_nls, cifs_remap(cifs_sb));
 182                 break;
 183
 184         case XATTR_CIFS_ACL: {
 185 #ifdef CONFIG_CIFS_ACL
 186                 u32 acllen;
 187                 struct cifs_ntsd *pacl;
 188
 189                 if (pTcon->ses->server->ops->get_acl == NULL)
 190                         goto out; /* rc already EOPNOTSUPP */
 191
 192                 pacl = pTcon->ses->server->ops->get_acl(cifs_sb,
 193                                 inode, full_path, &acllen);
 194                 if (IS_ERR(pacl)) {
 195                         rc = PTR_ERR(pacl);
 196                         cifs_dbg(VFS, "%s: error %zd getting sec desc\n",
 197                                  __func__, rc);
 198                 } else {
 199                         if (value) {
 200                                 if (acllen > size)
 201                                         acllen = -ERANGE;
 202                                 else
 203                                         memcpy(value, pacl, acllen);
 204                         }
 205                         rc = acllen;
 206                         kfree(pacl);
 207                 }
 208 #endif  /* CONFIG_CIFS_ACL */
 209                 break;
 210         }
 211
 212         case XATTR_ACL_ACCESS:
 213 #ifdef CONFIG_CIFS_POSIX
 214                 if (sb->s_flags & MS_POSIXACL)
 215                         rc = CIFSSMBGetPosixACL(xid, pTcon, full_path,
 216                                 value, size, ACL_TYPE_ACCESS,
 217                                 cifs_sb->local_nls,
 218                                 cifs_remap(cifs_sb));
 219 #endif  /* CONFIG_CIFS_POSIX */
 220                 break;
 221
 222         case XATTR_ACL_DEFAULT:
 223 #ifdef CONFIG_CIFS_POSIX
 224                 if (sb->s_flags & MS_POSIXACL)
 225                         rc = CIFSSMBGetPosixACL(xid, pTcon, full_path,
 226                                 value, size, ACL_TYPE_DEFAULT,
 227                                 cifs_sb->local_nls,
 228                                 cifs_remap(cifs_sb));
 229 #endif  /* CONFIG_CIFS_POSIX */
 230                 break;
 231         }
 232
 233         /* We could add an additional check for streams ie
 234             if proc/fs/cifs/streamstoxattr is set then
 235                 search server for EAs or streams to
 236                 returns as xattrs */
 237
 238         if (rc == -EINVAL)
 239                 rc = -EOPNOTSUPP;
 240
 241 out:
 242         kfree(full_path);
 243         free_xid(xid);
 244         cifs_put_tlink(tlink);
 245         return rc;
 246 }
 247
 248 ssize_t cifs_listxattr(struct dentry *direntry, char *data, size_t buf_size)
 249 {
 250         ssize_t rc = -EOPNOTSUPP;
 251         unsigned int xid;
 252         struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
 253         struct tcon_link *tlink;
 254         struct cifs_tcon *pTcon;
 255         char *full_path;
 256
 257         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
 258                 return -EOPNOTSUPP;
 259
 260         tlink = cifs_sb_tlink(cifs_sb);
 261         if (IS_ERR(tlink))
 262                 return PTR_ERR(tlink);
 263         pTcon = tlink_tcon(tlink);
 264
 265         xid = get_xid();
 266
 267         full_path = build_path_from_dentry(direntry);
 268         if (full_path == NULL) {
 269                 rc = -ENOMEM;
 270                 goto list_ea_exit;
 271         }
 272         /* return dos attributes as pseudo xattr */
 273         /* return alt name if available as pseudo attr */
 274
 275         /* if proc/fs/cifs/streamstoxattr is set then
 276                 search server for EAs or streams to
 277                 returns as xattrs */
 278
 279         if (pTcon->ses->server->ops->query_all_EAs)
 280                 rc = pTcon->ses->server->ops->query_all_EAs(xid, pTcon,
 281                                 full_path, NULL, data, buf_size,
 282                                 cifs_sb->local_nls, cifs_remap(cifs_sb));
 283 list_ea_exit:
 284         kfree(full_path);
 285         free_xid(xid);
 286         cifs_put_tlink(tlink);
 287         return rc;
 288 }
 289
 290 static const struct xattr_handler cifs_user_xattr_handler = {
 291         .prefix = XATTR_USER_PREFIX,
 292         .flags = XATTR_USER,
 293         .get = cifs_xattr_get,
 294         .set = cifs_xattr_set,
 295 };
 296
 297 /* os2.* attributes are treated like user.* attributes */
 298 static const struct xattr_handler cifs_os2_xattr_handler = {
 299         .prefix = XATTR_OS2_PREFIX,
 300         .flags = XATTR_USER,
 301         .get = cifs_xattr_get,
 302         .set = cifs_xattr_set,
 303 };
 304
 305 static const struct xattr_handler cifs_cifs_acl_xattr_handler = {
 306         .name = CIFS_XATTR_CIFS_ACL,
 307         .flags = XATTR_CIFS_ACL,
 308         .get = cifs_xattr_get,
 309         .set = cifs_xattr_set,
 310 };
 311
 312 static const struct xattr_handler cifs_posix_acl_access_xattr_handler = {
 313         .name = XATTR_NAME_POSIX_ACL_ACCESS,
 314         .flags = XATTR_ACL_ACCESS,
 315         .get = cifs_xattr_get,
 316         .set = cifs_xattr_set,
 317 };
 318
 319 static const struct xattr_handler cifs_posix_acl_default_xattr_handler = {
 320         .name = XATTR_NAME_POSIX_ACL_DEFAULT,
 321         .flags = XATTR_ACL_DEFAULT,
 322         .get = cifs_xattr_get,
 323         .set = cifs_xattr_set,
 324 };
 325
 326 const struct xattr_handler *cifs_xattr_handlers[] = {
 327         &cifs_user_xattr_handler,
 328         &cifs_os2_xattr_handler,
 329         &cifs_cifs_acl_xattr_handler,
 330         &cifs_posix_acl_access_xattr_handler,
 331         &cifs_posix_acl_default_xattr_handler,
 332         NULL
 333 };