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 #define CIFS_XATTR_ATTRIB "cifs.dosattrib"  /* full name: user.cifs.dosattrib */
  37 #define CIFS_XATTR_CREATETIME "cifs.creationtime"  /* user.cifs.creationtime */
  38 /* BB need to add server (Samba e.g) support for security and trusted prefix */
  39
  40 enum { XATTR_USER, XATTR_CIFS_ACL, XATTR_ACL_ACCESS, XATTR_ACL_DEFAULT };
  41
  42 static int cifs_xattr_set(const struct xattr_handler *handler,
  43                           struct dentry *dentry, struct inode *inode,
  44                           const char *name, const void *value,
  45                           size_t size, int flags)
  46 {
  47         int rc = -EOPNOTSUPP;
  48         unsigned int xid;
  49         struct super_block *sb = dentry->d_sb;
  50         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
  51         struct tcon_link *tlink;
  52         struct cifs_tcon *pTcon;
  53         char *full_path;
  54
  55         tlink = cifs_sb_tlink(cifs_sb);
  56         if (IS_ERR(tlink))
  57                 return PTR_ERR(tlink);
  58         pTcon = tlink_tcon(tlink);
  59
  60         xid = get_xid();
  61
  62         full_path = build_path_from_dentry(dentry);
  63         if (full_path == NULL) {
  64                 rc = -ENOMEM;
  65                 goto out;
  66         }
  67         /* return dos attributes as pseudo xattr */
  68         /* return alt name if available as pseudo attr */
  69
  70         /* if proc/fs/cifs/streamstoxattr is set then
  71                 search server for EAs or streams to
  72                 returns as xattrs */
  73         if (size > MAX_EA_VALUE_SIZE) {
  74                 cifs_dbg(FYI, "size of EA value too large\n");
  75                 rc = -EOPNOTSUPP;
  76                 goto out;
  77         }
  78
  79         switch (handler->flags) {
  80         case XATTR_USER:
  81                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
  82                         goto out;
  83
  84                 if (pTcon->ses->server->ops->set_EA)
  85                         rc = pTcon->ses->server->ops->set_EA(xid, pTcon,
  86                                 full_path, name, value, (__u16)size,
  87                                 cifs_sb->local_nls, cifs_remap(cifs_sb));
  88                 break;
  89
  90         case XATTR_CIFS_ACL: {
  91 #ifdef CONFIG_CIFS_ACL
  92                 struct cifs_ntsd *pacl;
  93
  94                 if (!value)
  95                         goto out;
  96                 pacl = kmalloc(size, GFP_KERNEL);
  97                 if (!pacl) {
  98                         rc = -ENOMEM;
  99                 } else {
 100                         memcpy(pacl, value, size);
 101                         if (value &&
 102                             pTcon->ses->server->ops->set_acl)
 103                                 rc = pTcon->ses->server->ops->set_acl(pacl,
 104                                                 size, inode,
 105                                                 full_path, CIFS_ACL_DACL);
 106                         else
 107                                 rc = -EOPNOTSUPP;
 108                         if (rc == 0) /* force revalidate of the inode */
 109                                 CIFS_I(inode)->time = 0;
 110                         kfree(pacl);
 111                 }
 112 #endif /* CONFIG_CIFS_ACL */
 113                 break;
 114         }
 115
 116         case XATTR_ACL_ACCESS:
 117 #ifdef CONFIG_CIFS_POSIX
 118                 if (!value)
 119                         goto out;
 120                 if (sb->s_flags & MS_POSIXACL)
 121                         rc = CIFSSMBSetPosixACL(xid, pTcon, full_path,
 122                                 value, (const int)size,
 123                                 ACL_TYPE_ACCESS, cifs_sb->local_nls,
 124                                 cifs_remap(cifs_sb));
 125 #endif  /* CONFIG_CIFS_POSIX */
 126                 break;
 127
 128         case XATTR_ACL_DEFAULT:
 129 #ifdef CONFIG_CIFS_POSIX
 130                 if (!value)
 131                         goto out;
 132                 if (sb->s_flags & MS_POSIXACL)
 133                         rc = CIFSSMBSetPosixACL(xid, pTcon, full_path,
 134                                 value, (const int)size,
 135                                 ACL_TYPE_DEFAULT, cifs_sb->local_nls,
 136                                 cifs_remap(cifs_sb));
 137 #endif  /* CONFIG_CIFS_POSIX */
 138                 break;
 139         }
 140
 141 out:
 142         kfree(full_path);
 143         free_xid(xid);
 144         cifs_put_tlink(tlink);
 145         return rc;
 146 }
 147
 148 static int cifs_attrib_get(struct dentry *dentry,
 149                            struct inode *inode, void *value,
 150                            size_t size)
 151 {
 152         ssize_t rc;
 153         __u32 *pattribute;
 154
 155         rc = cifs_revalidate_dentry_attr(dentry);
 156
 157         if (rc)
 158                 return rc;
 159
 160         if ((value == NULL) || (size == 0))
 161                 return sizeof(__u32);
 162         else if (size < sizeof(__u32))
 163                 return -ERANGE;
 164
 165         /* return dos attributes as pseudo xattr */
 166         pattribute = (__u32 *)value;
 167         *pattribute = CIFS_I(inode)->cifsAttrs;
 168
 169         return sizeof(__u32);
 170 }
 171
 172 static int cifs_creation_time_get(struct dentry *dentry, struct inode *inode,
 173                                   void *value, size_t size)
 174 {
 175         ssize_t rc;
 176         __u64 * pcreatetime;
 177
 178         rc = cifs_revalidate_dentry_attr(dentry);
 179         if (rc)
 180                 return rc;
 181
 182         if ((value == NULL) || (size == 0))
 183                 return sizeof(__u64);
 184         else if (size < sizeof(__u64))
 185                 return -ERANGE;
 186
 187         /* return dos attributes as pseudo xattr */
 188         pcreatetime = (__u64 *)value;
 189         *pcreatetime = CIFS_I(inode)->createtime;
 190         return sizeof(__u64);
 191 }
 192
 193
 194 static int cifs_xattr_get(const struct xattr_handler *handler,
 195                           struct dentry *dentry, struct inode *inode,
 196                           const char *name, void *value, size_t size)
 197 {
 198         ssize_t rc = -EOPNOTSUPP;
 199         unsigned int xid;
 200         struct super_block *sb = dentry->d_sb;
 201         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 202         struct tcon_link *tlink;
 203         struct cifs_tcon *pTcon;
 204         char *full_path;
 205
 206         tlink = cifs_sb_tlink(cifs_sb);
 207         if (IS_ERR(tlink))
 208                 return PTR_ERR(tlink);
 209         pTcon = tlink_tcon(tlink);
 210
 211         xid = get_xid();
 212
 213         full_path = build_path_from_dentry(dentry);
 214         if (full_path == NULL) {
 215                 rc = -ENOMEM;
 216                 goto out;
 217         }
 218
 219         /* return alt name if available as pseudo attr */
 220         switch (handler->flags) {
 221         case XATTR_USER:
 222                 cifs_dbg(FYI, "%s:querying user xattr %s\n", __func__, name);
 223                 if (strcmp(name, CIFS_XATTR_ATTRIB) == 0) {
 224                         rc = cifs_attrib_get(dentry, inode, value, size);
 225                         break;
 226                 } else if (strcmp(name, CIFS_XATTR_CREATETIME) == 0) {
 227                         rc = cifs_creation_time_get(dentry, inode, value, size);
 228                         break;
 229                 }
 230
 231                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
 232                         goto out;
 233
 234                 if (pTcon->ses->server->ops->query_all_EAs)
 235                         rc = pTcon->ses->server->ops->query_all_EAs(xid, pTcon,
 236                                 full_path, name, value, size, cifs_sb);
 237                 break;
 238
 239         case XATTR_CIFS_ACL: {
 240 #ifdef CONFIG_CIFS_ACL
 241                 u32 acllen;
 242                 struct cifs_ntsd *pacl;
 243
 244                 if (pTcon->ses->server->ops->get_acl == NULL)
 245                         goto out; /* rc already EOPNOTSUPP */
 246
 247                 pacl = pTcon->ses->server->ops->get_acl(cifs_sb,
 248                                 inode, full_path, &acllen);
 249                 if (IS_ERR(pacl)) {
 250                         rc = PTR_ERR(pacl);
 251                         cifs_dbg(VFS, "%s: error %zd getting sec desc\n",
 252                                  __func__, rc);
 253                 } else {
 254                         if (value) {
 255                                 if (acllen > size)
 256                                         acllen = -ERANGE;
 257                                 else
 258                                         memcpy(value, pacl, acllen);
 259                         }
 260                         rc = acllen;
 261                         kfree(pacl);
 262                 }
 263 #endif  /* CONFIG_CIFS_ACL */
 264                 break;
 265         }
 266
 267         case XATTR_ACL_ACCESS:
 268 #ifdef CONFIG_CIFS_POSIX
 269                 if (sb->s_flags & MS_POSIXACL)
 270                         rc = CIFSSMBGetPosixACL(xid, pTcon, full_path,
 271                                 value, size, ACL_TYPE_ACCESS,
 272                                 cifs_sb->local_nls,
 273                                 cifs_remap(cifs_sb));
 274 #endif  /* CONFIG_CIFS_POSIX */
 275                 break;
 276
 277         case XATTR_ACL_DEFAULT:
 278 #ifdef CONFIG_CIFS_POSIX
 279                 if (sb->s_flags & MS_POSIXACL)
 280                         rc = CIFSSMBGetPosixACL(xid, pTcon, full_path,
 281                                 value, size, ACL_TYPE_DEFAULT,
 282                                 cifs_sb->local_nls,
 283                                 cifs_remap(cifs_sb));
 284 #endif  /* CONFIG_CIFS_POSIX */
 285                 break;
 286         }
 287
 288         /* We could add an additional check for streams ie
 289             if proc/fs/cifs/streamstoxattr is set then
 290                 search server for EAs or streams to
 291                 returns as xattrs */
 292
 293         if (rc == -EINVAL)
 294                 rc = -EOPNOTSUPP;
 295
 296 out:
 297         kfree(full_path);
 298         free_xid(xid);
 299         cifs_put_tlink(tlink);
 300         return rc;
 301 }
 302
 303 ssize_t cifs_listxattr(struct dentry *direntry, char *data, size_t buf_size)
 304 {
 305         ssize_t rc = -EOPNOTSUPP;
 306         unsigned int xid;
 307         struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
 308         struct tcon_link *tlink;
 309         struct cifs_tcon *pTcon;
 310         char *full_path;
 311
 312         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
 313                 return -EOPNOTSUPP;
 314
 315         tlink = cifs_sb_tlink(cifs_sb);
 316         if (IS_ERR(tlink))
 317                 return PTR_ERR(tlink);
 318         pTcon = tlink_tcon(tlink);
 319
 320         xid = get_xid();
 321
 322         full_path = build_path_from_dentry(direntry);
 323         if (full_path == NULL) {
 324                 rc = -ENOMEM;
 325                 goto list_ea_exit;
 326         }
 327         /* return dos attributes as pseudo xattr */
 328         /* return alt name if available as pseudo attr */
 329
 330         /* if proc/fs/cifs/streamstoxattr is set then
 331                 search server for EAs or streams to
 332                 returns as xattrs */
 333
 334         if (pTcon->ses->server->ops->query_all_EAs)
 335                 rc = pTcon->ses->server->ops->query_all_EAs(xid, pTcon,
 336                                 full_path, NULL, data, buf_size, cifs_sb);
 337 list_ea_exit:
 338         kfree(full_path);
 339         free_xid(xid);
 340         cifs_put_tlink(tlink);
 341         return rc;
 342 }
 343
 344 static const struct xattr_handler cifs_user_xattr_handler = {
 345         .prefix = XATTR_USER_PREFIX,
 346         .flags = XATTR_USER,
 347         .get = cifs_xattr_get,
 348         .set = cifs_xattr_set,
 349 };
 350
 351 /* os2.* attributes are treated like user.* attributes */
 352 static const struct xattr_handler cifs_os2_xattr_handler = {
 353         .prefix = XATTR_OS2_PREFIX,
 354         .flags = XATTR_USER,
 355         .get = cifs_xattr_get,
 356         .set = cifs_xattr_set,
 357 };
 358
 359 static const struct xattr_handler cifs_cifs_acl_xattr_handler = {
 360         .name = CIFS_XATTR_CIFS_ACL,
 361         .flags = XATTR_CIFS_ACL,
 362         .get = cifs_xattr_get,
 363         .set = cifs_xattr_set,
 364 };
 365
 366 static const struct xattr_handler cifs_posix_acl_access_xattr_handler = {
 367         .name = XATTR_NAME_POSIX_ACL_ACCESS,
 368         .flags = XATTR_ACL_ACCESS,
 369         .get = cifs_xattr_get,
 370         .set = cifs_xattr_set,
 371 };
 372
 373 static const struct xattr_handler cifs_posix_acl_default_xattr_handler = {
 374         .name = XATTR_NAME_POSIX_ACL_DEFAULT,
 375         .flags = XATTR_ACL_DEFAULT,
 376         .get = cifs_xattr_get,
 377         .set = cifs_xattr_set,
 378 };
 379
 380 const struct xattr_handler *cifs_xattr_handlers[] = {
 381         &cifs_user_xattr_handler,
 382         &cifs_os2_xattr_handler,
 383         &cifs_cifs_acl_xattr_handler,
 384         &cifs_posix_acl_access_xattr_handler,
 385         &cifs_posix_acl_default_xattr_handler,
 386         NULL
 387 };