fs/xfs/xfs_xattr.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2008 Christoph Hellwig.
   4  * Portions Copyright (C) 2000-2008 Silicon Graphics, Inc.
   5  */
   6
   7 #include "xfs.h"
   8 #include "xfs_shared.h"
   9 #include "xfs_format.h"
  10 #include "xfs_log_format.h"
  11 #include "xfs_da_format.h"
  12 #include "xfs_inode.h"
  13 #include "xfs_attr.h"
  14 #include "xfs_acl.h"
  15 #include "xfs_da_btree.h"
  16
  17 #include <linux/posix_acl_xattr.h>
  18
  19
  20 static int
  21 xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused,
  22                 struct inode *inode, const char *name, void *value, size_t size)
  23 {
  24         struct xfs_da_args      args = {
  25                 .dp             = XFS_I(inode),
  26                 .attr_filter    = handler->flags,
  27                 .name           = name,
  28                 .namelen        = strlen(name),
  29                 .value          = value,
  30                 .valuelen       = size,
  31         };
  32         int                     error;
  33
  34         error = xfs_attr_get(&args);
  35         if (error)
  36                 return error;
  37         return args.valuelen;
  38 }
  39
  40 static int
  41 xfs_xattr_set(const struct xattr_handler *handler, struct dentry *unused,
  42                 struct inode *inode, const char *name, const void *value,
  43                 size_t size, int flags)
  44 {
  45         struct xfs_da_args      args = {
  46                 .dp             = XFS_I(inode),
  47                 .attr_filter    = handler->flags,
  48                 .attr_flags     = flags,
  49                 .name           = name,
  50                 .namelen        = strlen(name),
  51                 .value          = (void *)value,
  52                 .valuelen       = size,
  53         };
  54         int                     error;
  55
  56         error = xfs_attr_set(&args);
  57         if (!error && (handler->flags & XFS_ATTR_ROOT))
  58                 xfs_forget_acl(inode, name);
  59         return error;
  60 }
  61
  62 static const struct xattr_handler xfs_xattr_user_handler = {
  63         .prefix = XATTR_USER_PREFIX,
  64         .flags  = 0, /* no flags implies user namespace */
  65         .get    = xfs_xattr_get,
  66         .set    = xfs_xattr_set,
  67 };
  68
  69 static const struct xattr_handler xfs_xattr_trusted_handler = {
  70         .prefix = XATTR_TRUSTED_PREFIX,
  71         .flags  = XFS_ATTR_ROOT,
  72         .get    = xfs_xattr_get,
  73         .set    = xfs_xattr_set,
  74 };
  75
  76 static const struct xattr_handler xfs_xattr_security_handler = {
  77         .prefix = XATTR_SECURITY_PREFIX,
  78         .flags  = XFS_ATTR_SECURE,
  79         .get    = xfs_xattr_get,
  80         .set    = xfs_xattr_set,
  81 };
  82
  83 const struct xattr_handler *xfs_xattr_handlers[] = {
  84         &xfs_xattr_user_handler,
  85         &xfs_xattr_trusted_handler,
  86         &xfs_xattr_security_handler,
  87 #ifdef CONFIG_XFS_POSIX_ACL
  88         &posix_acl_access_xattr_handler,
  89         &posix_acl_default_xattr_handler,
  90 #endif
  91         NULL
  92 };
  93
  94 static void
  95 __xfs_xattr_put_listent(
  96         struct xfs_attr_list_context *context,
  97         char *prefix,
  98         int prefix_len,
  99         unsigned char *name,
 100         int namelen)
 101 {
 102         char *offset;
 103         int arraytop;
 104
 105         if (context->count < 0 || context->seen_enough)
 106                 return;
 107
 108         if (!context->buffer)
 109                 goto compute_size;
 110
 111         arraytop = context->count + prefix_len + namelen + 1;
 112         if (arraytop > context->firstu) {
 113                 context->count = -1;    /* insufficient space */
 114                 context->seen_enough = 1;
 115                 return;
 116         }
 117         offset = context->buffer + context->count;
 118         strncpy(offset, prefix, prefix_len);
 119         offset += prefix_len;
 120         strncpy(offset, (char *)name, namelen);                 /* real name */
 121         offset += namelen;
 122         *offset = '\0';
 123
 124 compute_size:
 125         context->count += prefix_len + namelen + 1;
 126         return;
 127 }
 128
 129 static void
 130 xfs_xattr_put_listent(
 131         struct xfs_attr_list_context *context,
 132         int             flags,
 133         unsigned char   *name,
 134         int             namelen,
 135         int             valuelen)
 136 {
 137         char *prefix;
 138         int prefix_len;
 139
 140         ASSERT(context->count >= 0);
 141
 142         if (flags & XFS_ATTR_ROOT) {
 143 #ifdef CONFIG_XFS_POSIX_ACL
 144                 if (namelen == SGI_ACL_FILE_SIZE &&
 145                     strncmp(name, SGI_ACL_FILE,
 146                             SGI_ACL_FILE_SIZE) == 0) {
 147                         __xfs_xattr_put_listent(
 148                                         context, XATTR_SYSTEM_PREFIX,
 149                                         XATTR_SYSTEM_PREFIX_LEN,
 150                                         XATTR_POSIX_ACL_ACCESS,
 151                                         strlen(XATTR_POSIX_ACL_ACCESS));
 152                 } else if (namelen == SGI_ACL_DEFAULT_SIZE &&
 153                          strncmp(name, SGI_ACL_DEFAULT,
 154                                  SGI_ACL_DEFAULT_SIZE) == 0) {
 155                         __xfs_xattr_put_listent(
 156                                         context, XATTR_SYSTEM_PREFIX,
 157                                         XATTR_SYSTEM_PREFIX_LEN,
 158                                         XATTR_POSIX_ACL_DEFAULT,
 159                                         strlen(XATTR_POSIX_ACL_DEFAULT));
 160                 }
 161 #endif
 162
 163                 /*
 164                  * Only show root namespace entries if we are actually allowed to
 165                  * see them.
 166                  */
 167                 if (!capable(CAP_SYS_ADMIN))
 168                         return;
 169
 170                 prefix = XATTR_TRUSTED_PREFIX;
 171                 prefix_len = XATTR_TRUSTED_PREFIX_LEN;
 172         } else if (flags & XFS_ATTR_SECURE) {
 173                 prefix = XATTR_SECURITY_PREFIX;
 174                 prefix_len = XATTR_SECURITY_PREFIX_LEN;
 175         } else {
 176                 prefix = XATTR_USER_PREFIX;
 177                 prefix_len = XATTR_USER_PREFIX_LEN;
 178         }
 179
 180         __xfs_xattr_put_listent(context, prefix, prefix_len, name,
 181                                 namelen);
 182         return;
 183 }
 184
 185 ssize_t
 186 xfs_vn_listxattr(
 187         struct dentry   *dentry,
 188         char            *data,
 189         size_t          size)
 190 {
 191         struct xfs_attr_list_context context;
 192         struct inode    *inode = d_inode(dentry);
 193         int             error;
 194
 195         /*
 196          * First read the regular on-disk attributes.
 197          */
 198         memset(&context, 0, sizeof(context));
 199         context.dp = XFS_I(inode);
 200         context.resynch = 1;
 201         context.buffer = size ? data : NULL;
 202         context.bufsize = size;
 203         context.firstu = context.bufsize;
 204         context.put_listent = xfs_xattr_put_listent;
 205
 206         error = xfs_attr_list(&context);
 207         if (error)
 208                 return error;
 209         if (context.count < 0)
 210                 return -ERANGE;
 211
 212         return context.count;
 213 }