fs/gfs2/acl.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
   4  *
   5  * This copyrighted material is made available to anyone wishing to use,
   6  * modify, copy, or redistribute it subject to the terms and conditions
   7  * of the GNU General Public License version 2.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/slab.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/completion.h>
  14 #include <linux/buffer_head.h>
  15 #include <linux/xattr.h>
  16 #include <linux/posix_acl.h>
  17 #include <linux/posix_acl_xattr.h>
  18 #include <linux/gfs2_ondisk.h>
  19
  20 #include "gfs2.h"
  21 #include "incore.h"
  22 #include "acl.h"
  23 #include "xattr.h"
  24 #include "glock.h"
  25 #include "inode.h"
  26 #include "meta_io.h"
  27 #include "trans.h"
  28 #include "util.h"
  29
  30 static const char *gfs2_acl_name(int type)
  31 {
  32         switch (type) {
  33         case ACL_TYPE_ACCESS:
  34                 return GFS2_POSIX_ACL_ACCESS;
  35         case ACL_TYPE_DEFAULT:
  36                 return GFS2_POSIX_ACL_DEFAULT;
  37         }
  38         return NULL;
  39 }
  40
  41 struct posix_acl *gfs2_get_acl(struct inode *inode, int type)
  42 {
  43         struct gfs2_inode *ip = GFS2_I(inode);
  44         struct posix_acl *acl;
  45         const char *name;
  46         char *data;
  47         int len;
  48
  49         if (!ip->i_eattr)
  50                 return NULL;
  51
  52         acl = get_cached_acl(&ip->i_inode, type);
  53         if (acl != ACL_NOT_CACHED)
  54                 return acl;
  55
  56         name = gfs2_acl_name(type);
  57         if (name == NULL)
  58                 return ERR_PTR(-EINVAL);
  59
  60         len = gfs2_xattr_acl_get(ip, name, &data);
  61         if (len < 0)
  62                 return ERR_PTR(len);
  63         if (len == 0)
  64                 return NULL;
  65
  66         acl = posix_acl_from_xattr(data, len);
  67         kfree(data);
  68         return acl;
  69 }
  70
  71 static int gfs2_set_mode(struct inode *inode, umode_t mode)
  72 {
  73         int error = 0;
  74
  75         if (mode != inode->i_mode) {
  76                 struct iattr iattr;
  77
  78                 iattr.ia_valid = ATTR_MODE;
  79                 iattr.ia_mode = mode;
  80
  81                 error = gfs2_setattr_simple(inode, &iattr);
  82         }
  83
  84         return error;
  85 }
  86
  87 static int gfs2_acl_set(struct inode *inode, int type, struct posix_acl *acl)
  88 {
  89         int error;
  90         int len;
  91         char *data;
  92         const char *name = gfs2_acl_name(type);
  93
  94         BUG_ON(name == NULL);
  95         len = posix_acl_to_xattr(acl, NULL, 0);
  96         if (len == 0)
  97                 return 0;
  98         data = kmalloc(len, GFP_NOFS);
  99         if (data == NULL)
 100                 return -ENOMEM;
 101         error = posix_acl_to_xattr(acl, data, len);
 102         if (error < 0)
 103                 goto out;
 104         error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
 105         if (!error)
 106                 set_cached_acl(inode, type, acl);
 107 out:
 108         kfree(data);
 109         return error;
 110 }
 111
 112 int gfs2_acl_create(struct gfs2_inode *dip, struct inode *inode)
 113 {
 114         struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
 115         struct posix_acl *acl;
 116         umode_t mode = inode->i_mode;
 117         int error = 0;
 118
 119         if (!sdp->sd_args.ar_posix_acl)
 120                 return 0;
 121         if (S_ISLNK(inode->i_mode))
 122                 return 0;
 123
 124         acl = gfs2_get_acl(&dip->i_inode, ACL_TYPE_DEFAULT);
 125         if (IS_ERR(acl))
 126                 return PTR_ERR(acl);
 127         if (!acl) {
 128                 mode &= ~current_umask();
 129                 if (mode != inode->i_mode)
 130                         error = gfs2_set_mode(inode, mode);
 131                 return error;
 132         }
 133
 134         if (S_ISDIR(inode->i_mode)) {
 135                 error = gfs2_acl_set(inode, ACL_TYPE_DEFAULT, acl);
 136                 if (error)
 137                         goto out;
 138         }
 139
 140         error = posix_acl_create(&acl, GFP_NOFS, &mode);
 141         if (error < 0)
 142                 return error;
 143
 144         if (error == 0)
 145                 goto munge;
 146
 147         error = gfs2_acl_set(inode, ACL_TYPE_ACCESS, acl);
 148         if (error)
 149                 goto out;
 150 munge:
 151         error = gfs2_set_mode(inode, mode);
 152 out:
 153         posix_acl_release(acl);
 154         return error;
 155 }
 156
 157 int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr)
 158 {
 159         struct inode *inode = &ip->i_inode;
 160         struct posix_acl *acl;
 161         char *data;
 162         unsigned int len;
 163         int error;
 164
 165         acl = gfs2_get_acl(&ip->i_inode, ACL_TYPE_ACCESS);
 166         if (IS_ERR(acl))
 167                 return PTR_ERR(acl);
 168         if (!acl)
 169                 return gfs2_setattr_simple(inode, attr);
 170
 171         error = posix_acl_chmod(&acl, GFP_NOFS, attr->ia_mode);
 172         if (error)
 173                 return error;
 174
 175         len = posix_acl_to_xattr(acl, NULL, 0);
 176         data = kmalloc(len, GFP_NOFS);
 177         error = -ENOMEM;
 178         if (data == NULL)
 179                 goto out;
 180         posix_acl_to_xattr(acl, data, len);
 181         error = gfs2_xattr_acl_chmod(ip, attr, data);
 182         kfree(data);
 183         set_cached_acl(&ip->i_inode, ACL_TYPE_ACCESS, acl);
 184
 185 out:
 186         posix_acl_release(acl);
 187         return error;
 188 }
 189
 190 static int gfs2_acl_type(const char *name)
 191 {
 192         if (strcmp(name, GFS2_POSIX_ACL_ACCESS) == 0)
 193                 return ACL_TYPE_ACCESS;
 194         if (strcmp(name, GFS2_POSIX_ACL_DEFAULT) == 0)
 195                 return ACL_TYPE_DEFAULT;
 196         return -EINVAL;
 197 }
 198
 199 static int gfs2_xattr_system_get(struct dentry *dentry, const char *name,
 200                                  void *buffer, size_t size, int xtype)
 201 {
 202         struct inode *inode = dentry->d_inode;
 203         struct gfs2_sbd *sdp = GFS2_SB(inode);
 204         struct posix_acl *acl;
 205         int type;
 206         int error;
 207
 208         if (!sdp->sd_args.ar_posix_acl)
 209                 return -EOPNOTSUPP;
 210
 211         type = gfs2_acl_type(name);
 212         if (type < 0)
 213                 return type;
 214
 215         acl = gfs2_get_acl(inode, type);
 216         if (IS_ERR(acl))
 217                 return PTR_ERR(acl);
 218         if (acl == NULL)
 219                 return -ENODATA;
 220
 221         error = posix_acl_to_xattr(acl, buffer, size);
 222         posix_acl_release(acl);
 223
 224         return error;
 225 }
 226
 227 static int gfs2_xattr_system_set(struct dentry *dentry, const char *name,
 228                                  const void *value, size_t size, int flags,
 229                                  int xtype)
 230 {
 231         struct inode *inode = dentry->d_inode;
 232         struct gfs2_sbd *sdp = GFS2_SB(inode);
 233         struct posix_acl *acl = NULL;
 234         int error = 0, type;
 235
 236         if (!sdp->sd_args.ar_posix_acl)
 237                 return -EOPNOTSUPP;
 238
 239         type = gfs2_acl_type(name);
 240         if (type < 0)
 241                 return type;
 242         if (flags & XATTR_CREATE)
 243                 return -EINVAL;
 244         if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
 245                 return value ? -EACCES : 0;
 246         if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
 247                 return -EPERM;
 248         if (S_ISLNK(inode->i_mode))
 249                 return -EOPNOTSUPP;
 250
 251         if (!value)
 252                 goto set_acl;
 253
 254         acl = posix_acl_from_xattr(value, size);
 255         if (!acl) {
 256                 /*
 257                  * acl_set_file(3) may request that we set default ACLs with
 258                  * zero length -- defend (gracefully) against that here.
 259                  */
 260                 goto out;
 261         }
 262         if (IS_ERR(acl)) {
 263                 error = PTR_ERR(acl);
 264                 goto out;
 265         }
 266
 267         error = posix_acl_valid(acl);
 268         if (error)
 269                 goto out_release;
 270
 271         error = -EINVAL;
 272         if (acl->a_count > GFS2_ACL_MAX_ENTRIES)
 273                 goto out_release;
 274
 275         if (type == ACL_TYPE_ACCESS) {
 276                 umode_t mode = inode->i_mode;
 277                 error = posix_acl_equiv_mode(acl, &mode);
 278
 279                 if (error <= 0) {
 280                         posix_acl_release(acl);
 281                         acl = NULL;
 282
 283                         if (error < 0)
 284                                 return error;
 285                 }
 286
 287                 error = gfs2_set_mode(inode, mode);
 288                 if (error)
 289                         goto out_release;
 290         }
 291
 292 set_acl:
 293         error = __gfs2_xattr_set(inode, name, value, size, 0, GFS2_EATYPE_SYS);
 294         if (!error) {
 295                 if (acl)
 296                         set_cached_acl(inode, type, acl);
 297                 else
 298                         forget_cached_acl(inode, type);
 299         }
 300 out_release:
 301         posix_acl_release(acl);
 302 out:
 303         return error;
 304 }
 305
 306 const struct xattr_handler gfs2_xattr_system_handler = {
 307         .prefix = XATTR_SYSTEM_PREFIX,
 308         .flags  = GFS2_EATYPE_SYS,
 309         .get    = gfs2_xattr_system_get,
 310         .set    = gfs2_xattr_system_set,
 311 };
 312