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 /*
  39  * Although these three are just aliases for the above, need to move away from
  40  * confusing users and using the 20+ year old term 'cifs' when it is no longer
  41  * secure, replaced by SMB2 (then even more highly secure SMB3) many years ago
  42  */
  43 #define SMB3_XATTR_CIFS_ACL "system.smb3_acl"
  44 #define SMB3_XATTR_ATTRIB "smb3.dosattrib"  /* full name: user.smb3.dosattrib */
  45 #define SMB3_XATTR_CREATETIME "smb3.creationtime"  /* user.smb3.creationtime */
  46 /* BB need to add server (Samba e.g) support for security and trusted prefix */
  47
  48 enum { XATTR_USER, XATTR_CIFS_ACL, XATTR_ACL_ACCESS, XATTR_ACL_DEFAULT };
  49
  50 static int cifs_xattr_set(const struct xattr_handler *handler,
  51                           struct dentry *dentry, struct inode *inode,
  52                           const char *name, const void *value,
  53                           size_t size, int flags)
  54 {
  55         int rc = -EOPNOTSUPP;
  56         unsigned int xid;
  57         struct super_block *sb = dentry->d_sb;
  58         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
  59         struct tcon_link *tlink;
  60         struct cifs_tcon *pTcon;
  61         char *full_path;
  62
  63         tlink = cifs_sb_tlink(cifs_sb);
  64         if (IS_ERR(tlink))
  65                 return PTR_ERR(tlink);
  66         pTcon = tlink_tcon(tlink);
  67
  68         xid = get_xid();
  69
  70         full_path = build_path_from_dentry(dentry);
  71         if (full_path == NULL) {
  72                 rc = -ENOMEM;
  73                 goto out;
  74         }
  75         /* return dos attributes as pseudo xattr */
  76         /* return alt name if available as pseudo attr */
  77
  78         /* if proc/fs/cifs/streamstoxattr is set then
  79                 search server for EAs or streams to
  80                 returns as xattrs */
  81         if (size > MAX_EA_VALUE_SIZE) {
  82                 cifs_dbg(FYI, "size of EA value too large\n");
  83                 rc = -EOPNOTSUPP;
  84                 goto out;
  85         }
  86
  87         switch (handler->flags) {
  88         case XATTR_USER:
  89                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
  90                         goto out;
  91
  92                 if (pTcon->ses->server->ops->set_EA)
  93                         rc = pTcon->ses->server->ops->set_EA(xid, pTcon,
  94                                 full_path, name, value, (__u16)size,
  95                                 cifs_sb->local_nls, cifs_sb);
  96                 break;
  97
  98         case XATTR_CIFS_ACL: {
  99 #ifdef CONFIG_CIFS_ACL
 100                 struct cifs_ntsd *pacl;
 101
 102                 if (!value)
 103                         goto out;
 104                 pacl = kmalloc(size, GFP_KERNEL);
 105                 if (!pacl) {
 106                         rc = -ENOMEM;
 107                 } else {
 108                         memcpy(pacl, value, size);
 109                         if (value &&
 110                             pTcon->ses->server->ops->set_acl)
 111                                 rc = pTcon->ses->server->ops->set_acl(pacl,
 112                                                 size, inode,
 113                                                 full_path, CIFS_ACL_DACL);
 114                         else
 115                                 rc = -EOPNOTSUPP;
 116                         if (rc == 0) /* force revalidate of the inode */
 117                                 CIFS_I(inode)->time = 0;
 118                         kfree(pacl);
 119                 }
 120 #endif /* CONFIG_CIFS_ACL */
 121                 break;
 122         }
 123
 124         case XATTR_ACL_ACCESS:
 125 #ifdef CONFIG_CIFS_POSIX
 126                 if (!value)
 127                         goto out;
 128                 if (sb->s_flags & SB_POSIXACL)
 129                         rc = CIFSSMBSetPosixACL(xid, pTcon, full_path,
 130                                 value, (const int)size,
 131                                 ACL_TYPE_ACCESS, cifs_sb->local_nls,
 132                                 cifs_remap(cifs_sb));
 133 #endif  /* CONFIG_CIFS_POSIX */
 134                 break;
 135
 136         case XATTR_ACL_DEFAULT:
 137 #ifdef CONFIG_CIFS_POSIX
 138                 if (!value)
 139                         goto out;
 140                 if (sb->s_flags & SB_POSIXACL)
 141                         rc = CIFSSMBSetPosixACL(xid, pTcon, full_path,
 142                                 value, (const int)size,
 143                                 ACL_TYPE_DEFAULT, cifs_sb->local_nls,
 144                                 cifs_remap(cifs_sb));
 145 #endif  /* CONFIG_CIFS_POSIX */
 146                 break;
 147         }
 148
 149 out:
 150         kfree(full_path);
 151         free_xid(xid);
 152         cifs_put_tlink(tlink);
 153         return rc;
 154 }
 155
 156 static int cifs_attrib_get(struct dentry *dentry,
 157                            struct inode *inode, void *value,
 158                            size_t size)
 159 {
 160         ssize_t rc;
 161         __u32 *pattribute;
 162
 163         rc = cifs_revalidate_dentry_attr(dentry);
 164
 165         if (rc)
 166                 return rc;
 167
 168         if ((value == NULL) || (size == 0))
 169                 return sizeof(__u32);
 170         else if (size < sizeof(__u32))
 171                 return -ERANGE;
 172
 173         /* return dos attributes as pseudo xattr */
 174         pattribute = (__u32 *)value;
 175         *pattribute = CIFS_I(inode)->cifsAttrs;
 176
 177         return sizeof(__u32);
 178 }
 179
 180 static int cifs_creation_time_get(struct dentry *dentry, struct inode *inode,
 181                                   void *value, size_t size)
 182 {
 183         ssize_t rc;
 184         __u64 * pcreatetime;
 185
 186         rc = cifs_revalidate_dentry_attr(dentry);
 187         if (rc)
 188                 return rc;
 189
 190         if ((value == NULL) || (size == 0))
 191                 return sizeof(__u64);
 192         else if (size < sizeof(__u64))
 193                 return -ERANGE;
 194
 195         /* return dos attributes as pseudo xattr */
 196         pcreatetime = (__u64 *)value;
 197         *pcreatetime = CIFS_I(inode)->createtime;
 198         return sizeof(__u64);
 199 }
 200
 201
 202 static int cifs_xattr_get(const struct xattr_handler *handler,
 203                           struct dentry *dentry, struct inode *inode,
 204                           const char *name, void *value, size_t size)
 205 {
 206         ssize_t rc = -EOPNOTSUPP;
 207         unsigned int xid;
 208         struct super_block *sb = dentry->d_sb;
 209         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 210         struct tcon_link *tlink;
 211         struct cifs_tcon *pTcon;
 212         char *full_path;
 213
 214         tlink = cifs_sb_tlink(cifs_sb);
 215         if (IS_ERR(tlink))
 216                 return PTR_ERR(tlink);
 217         pTcon = tlink_tcon(tlink);
 218
 219         xid = get_xid();
 220
 221         full_path = build_path_from_dentry(dentry);
 222         if (full_path == NULL) {
 223                 rc = -ENOMEM;
 224                 goto out;
 225         }
 226
 227         /* return alt name if available as pseudo attr */
 228         switch (handler->flags) {
 229         case XATTR_USER:
 230                 cifs_dbg(FYI, "%s:querying user xattr %s\n", __func__, name);
 231                 if ((strcmp(name, CIFS_XATTR_ATTRIB) == 0) ||
 232                     (strcmp(name, SMB3_XATTR_ATTRIB) == 0)) {
 233                         rc = cifs_attrib_get(dentry, inode, value, size);
 234                         break;
 235                 } else if ((strcmp(name, CIFS_XATTR_CREATETIME) == 0) ||
 236                     (strcmp(name, SMB3_XATTR_CREATETIME) == 0)) {
 237                         rc = cifs_creation_time_get(dentry, inode, value, size);
 238                         break;
 239                 }
 240
 241                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
 242                         goto out;
 243
 244                 if (pTcon->ses->server->ops->query_all_EAs)
 245                         rc = pTcon->ses->server->ops->query_all_EAs(xid, pTcon,
 246                                 full_path, name, value, size, cifs_sb);
 247                 break;
 248
 249         case XATTR_CIFS_ACL: {
 250 #ifdef CONFIG_CIFS_ACL
 251                 u32 acllen;
 252                 struct cifs_ntsd *pacl;
 253
 254                 if (pTcon->ses->server->ops->get_acl == NULL)
 255                         goto out; /* rc already EOPNOTSUPP */
 256
 257                 pacl = pTcon->ses->server->ops->get_acl(cifs_sb,
 258                                 inode, full_path, &acllen);
 259                 if (IS_ERR(pacl)) {
 260                         rc = PTR_ERR(pacl);
 261                         cifs_dbg(VFS, "%s: error %zd getting sec desc\n",
 262                                  __func__, rc);
 263                 } else {
 264                         if (value) {
 265                                 if (acllen > size)
 266                                         acllen = -ERANGE;
 267                                 else
 268                                         memcpy(value, pacl, acllen);
 269                         }
 270                         rc = acllen;
 271                         kfree(pacl);
 272                 }
 273 #endif  /* CONFIG_CIFS_ACL */
 274                 break;
 275         }
 276
 277         case XATTR_ACL_ACCESS:
 278 #ifdef CONFIG_CIFS_POSIX
 279                 if (sb->s_flags & SB_POSIXACL)
 280                         rc = CIFSSMBGetPosixACL(xid, pTcon, full_path,
 281                                 value, size, ACL_TYPE_ACCESS,
 282                                 cifs_sb->local_nls,
 283                                 cifs_remap(cifs_sb));
 284 #endif  /* CONFIG_CIFS_POSIX */
 285                 break;
 286
 287         case XATTR_ACL_DEFAULT:
 288 #ifdef CONFIG_CIFS_POSIX
 289                 if (sb->s_flags & SB_POSIXACL)
 290                         rc = CIFSSMBGetPosixACL(xid, pTcon, full_path,
 291                                 value, size, ACL_TYPE_DEFAULT,
 292                                 cifs_sb->local_nls,
 293                                 cifs_remap(cifs_sb));
 294 #endif  /* CONFIG_CIFS_POSIX */
 295                 break;
 296         }
 297
 298         /* We could add an additional check for streams ie
 299             if proc/fs/cifs/streamstoxattr is set then
 300                 search server for EAs or streams to
 301                 returns as xattrs */
 302
 303         if (rc == -EINVAL)
 304                 rc = -EOPNOTSUPP;
 305
 306 out:
 307         kfree(full_path);
 308         free_xid(xid);
 309         cifs_put_tlink(tlink);
 310         return rc;
 311 }
 312
 313 ssize_t cifs_listxattr(struct dentry *direntry, char *data, size_t buf_size)
 314 {
 315         ssize_t rc = -EOPNOTSUPP;
 316         unsigned int xid;
 317         struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
 318         struct tcon_link *tlink;
 319         struct cifs_tcon *pTcon;
 320         char *full_path;
 321
 322         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
 323                 return -EOPNOTSUPP;
 324
 325         tlink = cifs_sb_tlink(cifs_sb);
 326         if (IS_ERR(tlink))
 327                 return PTR_ERR(tlink);
 328         pTcon = tlink_tcon(tlink);
 329
 330         xid = get_xid();
 331
 332         full_path = build_path_from_dentry(direntry);
 333         if (full_path == NULL) {
 334                 rc = -ENOMEM;
 335                 goto list_ea_exit;
 336         }
 337         /* return dos attributes as pseudo xattr */
 338         /* return alt name if available as pseudo attr */
 339
 340         /* if proc/fs/cifs/streamstoxattr is set then
 341                 search server for EAs or streams to
 342                 returns as xattrs */
 343
 344         if (pTcon->ses->server->ops->query_all_EAs)
 345                 rc = pTcon->ses->server->ops->query_all_EAs(xid, pTcon,
 346                                 full_path, NULL, data, buf_size, cifs_sb);
 347 list_ea_exit:
 348         kfree(full_path);
 349         free_xid(xid);
 350         cifs_put_tlink(tlink);
 351         return rc;
 352 }
 353
 354 static const struct xattr_handler cifs_user_xattr_handler = {
 355         .prefix = XATTR_USER_PREFIX,
 356         .flags = XATTR_USER,
 357         .get = cifs_xattr_get,
 358         .set = cifs_xattr_set,
 359 };
 360
 361 /* os2.* attributes are treated like user.* attributes */
 362 static const struct xattr_handler cifs_os2_xattr_handler = {
 363         .prefix = XATTR_OS2_PREFIX,
 364         .flags = XATTR_USER,
 365         .get = cifs_xattr_get,
 366         .set = cifs_xattr_set,
 367 };
 368
 369 static const struct xattr_handler cifs_cifs_acl_xattr_handler = {
 370         .name = CIFS_XATTR_CIFS_ACL,
 371         .flags = XATTR_CIFS_ACL,
 372         .get = cifs_xattr_get,
 373         .set = cifs_xattr_set,
 374 };
 375
 376 /*
 377  * Although this is just an alias for the above, need to move away from
 378  * confusing users and using the 20 year old term 'cifs' when it is no
 379  * longer secure and was replaced by SMB2/SMB3 a long time ago, and
 380  * SMB3 and later are highly secure.
 381  */
 382 static const struct xattr_handler smb3_acl_xattr_handler = {
 383         .name = SMB3_XATTR_CIFS_ACL,
 384         .flags = XATTR_CIFS_ACL,
 385         .get = cifs_xattr_get,
 386         .set = cifs_xattr_set,
 387 };
 388
 389 static const struct xattr_handler cifs_posix_acl_access_xattr_handler = {
 390         .name = XATTR_NAME_POSIX_ACL_ACCESS,
 391         .flags = XATTR_ACL_ACCESS,
 392         .get = cifs_xattr_get,
 393         .set = cifs_xattr_set,
 394 };
 395
 396 static const struct xattr_handler cifs_posix_acl_default_xattr_handler = {
 397         .name = XATTR_NAME_POSIX_ACL_DEFAULT,
 398         .flags = XATTR_ACL_DEFAULT,
 399         .get = cifs_xattr_get,
 400         .set = cifs_xattr_set,
 401 };
 402
 403 const struct xattr_handler *cifs_xattr_handlers[] = {
 404         &cifs_user_xattr_handler,
 405         &cifs_os2_xattr_handler,
 406         &cifs_cifs_acl_xattr_handler,
 407         &smb3_acl_xattr_handler, /* alias for above since avoiding "cifs" */
 408         &cifs_posix_acl_access_xattr_handler,
 409         &cifs_posix_acl_default_xattr_handler,
 410         NULL
 411 };