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 static struct posix_acl *gfs2_acl_get(struct gfs2_inode *ip, int type)
  42 {
  43         struct posix_acl *acl;
  44         const char *name;
  45         char *data;
  46         int len;
  47
  48         if (!ip->i_eattr)
  49                 return NULL;
  50
  51         acl = get_cached_acl(&ip->i_inode, type);
  52         if (acl != ACL_NOT_CACHED)
  53                 return acl;
  54
  55         name = gfs2_acl_name(type);
  56         if (name == NULL)
  57                 return ERR_PTR(-EINVAL);
  58
  59         len = gfs2_xattr_acl_get(ip, name, &data);
  60         if (len < 0)
  61                 return ERR_PTR(len);
  62         if (len == 0)
  63                 return NULL;
  64
  65         acl = posix_acl_from_xattr(data, len);
  66         kfree(data);
  67         return acl;
  68 }
  69
  70 struct posix_acl *gfs2_get_acl(struct inode *inode, int type)
  71 {
  72         return gfs2_acl_get(GFS2_I(inode), type);
  73 }
  74
  75 static int gfs2_set_mode(struct inode *inode, umode_t mode)
  76 {
  77         int error = 0;
  78
  79         if (mode != inode->i_mode) {
  80                 struct iattr iattr;
  81
  82                 iattr.ia_valid = ATTR_MODE;
  83                 iattr.ia_mode = mode;
  84
  85                 error = gfs2_setattr_simple(inode, &iattr);
  86         }
  87
  88         return error;
  89 }
  90
  91 static int gfs2_acl_set(struct inode *inode, int type, struct posix_acl *acl)
  92 {
  93         int error;
  94         int len;
  95         char *data;
  96         const char *name = gfs2_acl_name(type);
  97
  98         BUG_ON(name == NULL);
  99         len = posix_acl_to_xattr(acl, NULL, 0);
 100         if (len == 0)
 101                 return 0;
 102         data = kmalloc(len, GFP_NOFS);
 103         if (data == NULL)
 104                 return -ENOMEM;
 105         error = posix_acl_to_xattr(acl, data, len);
 106         if (error < 0)
 107                 goto out;
 108         error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
 109         if (!error)
 110                 set_cached_acl(inode, type, acl);
 111 out:
 112         kfree(data);
 113         return error;
 114 }
 115
 116 int gfs2_acl_create(struct gfs2_inode *dip, struct inode *inode)
 117 {
 118         struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
 119         struct posix_acl *acl;
 120         umode_t mode = inode->i_mode;
 121         int error = 0;
 122
 123         if (!sdp->sd_args.ar_posix_acl)
 124                 return 0;
 125         if (S_ISLNK(inode->i_mode))
 126                 return 0;
 127
 128         acl = gfs2_acl_get(dip, ACL_TYPE_DEFAULT);
 129         if (IS_ERR(acl))
 130                 return PTR_ERR(acl);
 131         if (!acl) {
 132                 mode &= ~current_umask();
 133                 if (mode != inode->i_mode)
 134                         error = gfs2_set_mode(inode, mode);
 135                 return error;
 136         }
 137
 138         if (S_ISDIR(inode->i_mode)) {
 139                 error = gfs2_acl_set(inode, ACL_TYPE_DEFAULT, acl);
 140                 if (error)
 141                         goto out;
 142         }
 143
 144         error = posix_acl_create(&acl, GFP_NOFS, &mode);
 145         if (error < 0)
 146                 return error;
 147
 148         if (error == 0)
 149                 goto munge;
 150
 151         error = gfs2_acl_set(inode, ACL_TYPE_ACCESS, acl);
 152         if (error)
 153                 goto out;
 154 munge:
 155         error = gfs2_set_mode(inode, mode);
 156 out:
 157         posix_acl_release(acl);
 158         return error;
 159 }
 160
 161 int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr)
 162 {
 163         struct inode *inode = &ip->i_inode;
 164         struct posix_acl *acl;
 165         char *data;
 166         unsigned int len;
 167         int error;
 168
 169         acl = gfs2_acl_get(ip, ACL_TYPE_ACCESS);
 170         if (IS_ERR(acl))
 171                 return PTR_ERR(acl);
 172         if (!acl)
 173                 return gfs2_setattr_simple(inode, attr);
 174
 175         error = posix_acl_chmod(&acl, GFP_NOFS, attr->ia_mode);
 176         if (error)
 177                 return error;
 178
 179         len = posix_acl_to_xattr(acl, NULL, 0);
 180         data = kmalloc(len, GFP_NOFS);
 181         error = -ENOMEM;
 182         if (data == NULL)
 183                 goto out;
 184         posix_acl_to_xattr(acl, data, len);
 185         error = gfs2_xattr_acl_chmod(ip, attr, data);
 186         kfree(data);
 187         set_cached_acl(&ip->i_inode, ACL_TYPE_ACCESS, acl);
 188
 189 out:
 190         posix_acl_release(acl);
 191         return error;
 192 }
 193
 194 static int gfs2_acl_type(const char *name)
 195 {
 196         if (strcmp(name, GFS2_POSIX_ACL_ACCESS) == 0)
 197                 return ACL_TYPE_ACCESS;
 198         if (strcmp(name, GFS2_POSIX_ACL_DEFAULT) == 0)
 199                 return ACL_TYPE_DEFAULT;
 200         return -EINVAL;
 201 }
 202
 203 static int gfs2_xattr_system_get(struct dentry *dentry, const char *name,
 204                                  void *buffer, size_t size, int xtype)
 205 {
 206         struct inode *inode = dentry->d_inode;
 207         struct gfs2_sbd *sdp = GFS2_SB(inode);
 208         struct posix_acl *acl;
 209         int type;
 210         int error;
 211
 212         if (!sdp->sd_args.ar_posix_acl)
 213                 return -EOPNOTSUPP;
 214
 215         type = gfs2_acl_type(name);
 216         if (type < 0)
 217                 return type;
 218
 219         acl = gfs2_acl_get(GFS2_I(inode), type);
 220         if (IS_ERR(acl))
 221                 return PTR_ERR(acl);
 222         if (acl == NULL)
 223                 return -ENODATA;
 224
 225         error = posix_acl_to_xattr(acl, buffer, size);
 226         posix_acl_release(acl);
 227
 228         return error;
 229 }
 230
 231 static int gfs2_xattr_system_set(struct dentry *dentry, const char *name,
 232                                  const void *value, size_t size, int flags,
 233                                  int xtype)
 234 {
 235         struct inode *inode = dentry->d_inode;
 236         struct gfs2_sbd *sdp = GFS2_SB(inode);
 237         struct posix_acl *acl = NULL;
 238         int error = 0, type;
 239
 240         if (!sdp->sd_args.ar_posix_acl)
 241                 return -EOPNOTSUPP;
 242
 243         type = gfs2_acl_type(name);
 244         if (type < 0)
 245                 return type;
 246         if (flags & XATTR_CREATE)
 247                 return -EINVAL;
 248         if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
 249                 return value ? -EACCES : 0;
 250         if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
 251                 return -EPERM;
 252         if (S_ISLNK(inode->i_mode))
 253                 return -EOPNOTSUPP;
 254
 255         if (!value)
 256                 goto set_acl;
 257
 258         acl = posix_acl_from_xattr(value, size);
 259         if (!acl) {
 260                 /*
 261                  * acl_set_file(3) may request that we set default ACLs with
 262                  * zero length -- defend (gracefully) against that here.
 263                  */
 264                 goto out;
 265         }
 266         if (IS_ERR(acl)) {
 267                 error = PTR_ERR(acl);
 268                 goto out;
 269         }
 270
 271         error = posix_acl_valid(acl);
 272         if (error)
 273                 goto out_release;
 274
 275         error = -EINVAL;
 276         if (acl->a_count > GFS2_ACL_MAX_ENTRIES)
 277                 goto out_release;
 278
 279         if (type == ACL_TYPE_ACCESS) {
 280                 umode_t mode = inode->i_mode;
 281                 error = posix_acl_equiv_mode(acl, &mode);
 282
 283                 if (error <= 0) {
 284                         posix_acl_release(acl);
 285                         acl = NULL;
 286
 287                         if (error < 0)
 288                                 return error;
 289                 }
 290
 291                 error = gfs2_set_mode(inode, mode);
 292                 if (error)
 293                         goto out_release;
 294         }
 295
 296 set_acl:
 297         error = __gfs2_xattr_set(inode, name, value, size, 0, GFS2_EATYPE_SYS);
 298         if (!error) {
 299                 if (acl)
 300                         set_cached_acl(inode, type, acl);
 301                 else
 302                         forget_cached_acl(inode, type);
 303         }
 304 out_release:
 305         posix_acl_release(acl);
 306 out:
 307         return error;
 308 }
 309
 310 const struct xattr_handler gfs2_xattr_system_handler = {
 311         .prefix = XATTR_SYSTEM_PREFIX,
 312         .flags  = GFS2_EATYPE_SYS,
 313         .get    = gfs2_xattr_system_get,
 314         .set    = gfs2_xattr_system_set,
 315 };
 316