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