fs/xfs/xfs_xattr.c

   1 /*
   2  * Copyright (C) 2008 Christoph Hellwig.
   3  * Portions Copyright (C) 2000-2008 Silicon Graphics, Inc.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18
  19 #include "xfs.h"
  20 #include "xfs_format.h"
  21 #include "xfs_log_format.h"
  22 #include "xfs_trans_resv.h"
  23 #include "xfs_mount.h"
  24 #include "xfs_da_format.h"
  25 #include "xfs_inode.h"
  26 #include "xfs_attr.h"
  27 #include "xfs_attr_leaf.h"
  28 #include "xfs_acl.h"
  29
  30 #include <linux/posix_acl_xattr.h>
  31 #include <linux/xattr.h>
  32
  33
  34 static int
  35 xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused,
  36                 struct inode *inode, const char *name, void *value, size_t size)
  37 {
  38         int xflags = handler->flags;
  39         struct xfs_inode *ip = XFS_I(inode);
  40         int error, asize = size;
  41
  42         /* Convert Linux syscall to XFS internal ATTR flags */
  43         if (!size) {
  44                 xflags |= ATTR_KERNOVAL;
  45                 value = NULL;
  46         }
  47
  48         error = xfs_attr_get(ip, (unsigned char *)name, value, &asize, xflags);
  49         if (error)
  50                 return error;
  51         return asize;
  52 }
  53
  54 void
  55 xfs_forget_acl(
  56         struct inode            *inode,
  57         const char              *name,
  58         int                     xflags)
  59 {
  60         /*
  61          * Invalidate any cached ACLs if the user has bypassed the ACL
  62          * interface. We don't validate the content whatsoever so it is caller
  63          * responsibility to provide data in valid format and ensure i_mode is
  64          * consistent.
  65          */
  66         if (xflags & ATTR_ROOT) {
  67 #ifdef CONFIG_XFS_POSIX_ACL
  68                 if (!strcmp(name, SGI_ACL_FILE))
  69                         forget_cached_acl(inode, ACL_TYPE_ACCESS);
  70                 else if (!strcmp(name, SGI_ACL_DEFAULT))
  71                         forget_cached_acl(inode, ACL_TYPE_DEFAULT);
  72 #endif
  73         }
  74 }
  75
  76 static int
  77 xfs_xattr_set(const struct xattr_handler *handler, struct dentry *unused,
  78                 struct inode *inode, const char *name, const void *value,
  79                 size_t size, int flags)
  80 {
  81         int                     xflags = handler->flags;
  82         struct xfs_inode        *ip = XFS_I(inode);
  83         int                     error;
  84
  85         /* Convert Linux syscall to XFS internal ATTR flags */
  86         if (flags & XATTR_CREATE)
  87                 xflags |= ATTR_CREATE;
  88         if (flags & XATTR_REPLACE)
  89                 xflags |= ATTR_REPLACE;
  90
  91         if (!value)
  92                 return xfs_attr_remove(ip, (unsigned char *)name, xflags);
  93         error = xfs_attr_set(ip, (unsigned char *)name,
  94                                 (void *)value, size, xflags);
  95         if (!error)
  96                 xfs_forget_acl(inode, name, xflags);
  97
  98         return error;
  99 }
 100
 101 static const struct xattr_handler xfs_xattr_user_handler = {
 102         .prefix = XATTR_USER_PREFIX,
 103         .flags  = 0, /* no flags implies user namespace */
 104         .get    = xfs_xattr_get,
 105         .set    = xfs_xattr_set,
 106 };
 107
 108 static const struct xattr_handler xfs_xattr_trusted_handler = {
 109         .prefix = XATTR_TRUSTED_PREFIX,
 110         .flags  = ATTR_ROOT,
 111         .get    = xfs_xattr_get,
 112         .set    = xfs_xattr_set,
 113 };
 114
 115 static const struct xattr_handler xfs_xattr_security_handler = {
 116         .prefix = XATTR_SECURITY_PREFIX,
 117         .flags  = ATTR_SECURE,
 118         .get    = xfs_xattr_get,
 119         .set    = xfs_xattr_set,
 120 };
 121
 122 const struct xattr_handler *xfs_xattr_handlers[] = {
 123         &xfs_xattr_user_handler,
 124         &xfs_xattr_trusted_handler,
 125         &xfs_xattr_security_handler,
 126 #ifdef CONFIG_XFS_POSIX_ACL
 127         &posix_acl_access_xattr_handler,
 128         &posix_acl_default_xattr_handler,
 129 #endif
 130         NULL
 131 };
 132
 133 static void
 134 __xfs_xattr_put_listent(
 135         struct xfs_attr_list_context *context,
 136         char *prefix,
 137         int prefix_len,
 138         unsigned char *name,
 139         int namelen)
 140 {
 141         char *offset;
 142         int arraytop;
 143
 144         if (!context->alist)
 145                 goto compute_size;
 146
 147         arraytop = context->count + prefix_len + namelen + 1;
 148         if (arraytop > context->firstu) {
 149                 context->count = -1;    /* insufficient space */
 150                 context->seen_enough = 1;
 151                 return;
 152         }
 153         offset = (char *)context->alist + context->count;
 154         strncpy(offset, prefix, prefix_len);
 155         offset += prefix_len;
 156         strncpy(offset, (char *)name, namelen);                 /* real name */
 157         offset += namelen;
 158         *offset = '\0';
 159
 160 compute_size:
 161         context->count += prefix_len + namelen + 1;
 162         return;
 163 }
 164
 165 static void
 166 xfs_xattr_put_listent(
 167         struct xfs_attr_list_context *context,
 168         int             flags,
 169         unsigned char   *name,
 170         int             namelen,
 171         int             valuelen)
 172 {
 173         char *prefix;
 174         int prefix_len;
 175
 176         ASSERT(context->count >= 0);
 177
 178         if (flags & XFS_ATTR_ROOT) {
 179 #ifdef CONFIG_XFS_POSIX_ACL
 180                 if (namelen == SGI_ACL_FILE_SIZE &&
 181                     strncmp(name, SGI_ACL_FILE,
 182                             SGI_ACL_FILE_SIZE) == 0) {
 183                         __xfs_xattr_put_listent(
 184                                         context, XATTR_SYSTEM_PREFIX,
 185                                         XATTR_SYSTEM_PREFIX_LEN,
 186                                         XATTR_POSIX_ACL_ACCESS,
 187                                         strlen(XATTR_POSIX_ACL_ACCESS));
 188                 } else if (namelen == SGI_ACL_DEFAULT_SIZE &&
 189                          strncmp(name, SGI_ACL_DEFAULT,
 190                                  SGI_ACL_DEFAULT_SIZE) == 0) {
 191                         __xfs_xattr_put_listent(
 192                                         context, XATTR_SYSTEM_PREFIX,
 193                                         XATTR_SYSTEM_PREFIX_LEN,
 194                                         XATTR_POSIX_ACL_DEFAULT,
 195                                         strlen(XATTR_POSIX_ACL_DEFAULT));
 196                 }
 197 #endif
 198
 199                 /*
 200                  * Only show root namespace entries if we are actually allowed to
 201                  * see them.
 202                  */
 203                 if (!capable(CAP_SYS_ADMIN))
 204                         return;
 205
 206                 prefix = XATTR_TRUSTED_PREFIX;
 207                 prefix_len = XATTR_TRUSTED_PREFIX_LEN;
 208         } else if (flags & XFS_ATTR_SECURE) {
 209                 prefix = XATTR_SECURITY_PREFIX;
 210                 prefix_len = XATTR_SECURITY_PREFIX_LEN;
 211         } else {
 212                 prefix = XATTR_USER_PREFIX;
 213                 prefix_len = XATTR_USER_PREFIX_LEN;
 214         }
 215
 216         __xfs_xattr_put_listent(context, prefix, prefix_len, name,
 217                                 namelen);
 218         return;
 219 }
 220
 221 ssize_t
 222 xfs_vn_listxattr(
 223         struct dentry   *dentry,
 224         char            *data,
 225         size_t          size)
 226 {
 227         struct xfs_attr_list_context context;
 228         struct attrlist_cursor_kern cursor = { 0 };
 229         struct inode    *inode = d_inode(dentry);
 230         int             error;
 231
 232         /*
 233          * First read the regular on-disk attributes.
 234          */
 235         memset(&context, 0, sizeof(context));
 236         context.dp = XFS_I(inode);
 237         context.cursor = &cursor;
 238         context.resynch = 1;
 239         context.alist = size ? data : NULL;
 240         context.bufsize = size;
 241         context.firstu = context.bufsize;
 242         context.put_listent = xfs_xattr_put_listent;
 243
 244         error = xfs_attr_list_int(&context);
 245         if (error)
 246                 return error;
 247         if (context.count < 0)
 248                 return -ERANGE;
 249
 250         return context.count;
 251 }