root/fs/cifs/xattr.c

DEFINITIONS

1. cifs_xattr_set
2. cifs_attrib_get
3. cifs_creation_time_get
4. cifs_xattr_get
5. cifs_listxattr

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