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/posix_acl.h>
  16 #include <linux/posix_acl_xattr.h>
  17 #include <linux/gfs2_ondisk.h>
  18 #include <linux/lm_interface.h>
  19
  20 #include "gfs2.h"
  21 #include "incore.h"
  22 #include "acl.h"
  23 #include "eaops.h"
  24 #include "eattr.h"
  25 #include "glock.h"
  26 #include "inode.h"
  27 #include "meta_io.h"
  28 #include "trans.h"
  29 #include "util.h"
  30
  31 #define ACL_ACCESS 1
  32 #define ACL_DEFAULT 0
  33
  34 int gfs2_acl_validate_set(struct gfs2_inode *ip, int access,
  35                       struct gfs2_ea_request *er,
  36                       int *remove, mode_t *mode)
  37 {
  38         struct posix_acl *acl;
  39         int error;
  40
  41         error = gfs2_acl_validate_remove(ip, access);
  42         if (error)
  43                 return error;
  44
  45         if (!er->er_data)
  46                 return -EINVAL;
  47
  48         acl = posix_acl_from_xattr(er->er_data, er->er_data_len);
  49         if (IS_ERR(acl))
  50                 return PTR_ERR(acl);
  51         if (!acl) {
  52                 *remove = 1;
  53                 return 0;
  54         }
  55
  56         error = posix_acl_valid(acl);
  57         if (error)
  58                 goto out;
  59
  60         if (access) {
  61                 error = posix_acl_equiv_mode(acl, mode);
  62                 if (!error)
  63                         *remove = 1;
  64                 else if (error > 0)
  65                         error = 0;
  66         }
  67
  68 out:
  69         posix_acl_release(acl);
  70         return error;
  71 }
  72
  73 int gfs2_acl_validate_remove(struct gfs2_inode *ip, int access)
  74 {
  75         if (!GFS2_SB(&ip->i_inode)->sd_args.ar_posix_acl)
  76                 return -EOPNOTSUPP;
  77         if (current->fsuid != ip->i_di.di_uid && !capable(CAP_FOWNER))
  78                 return -EPERM;
  79         if (S_ISLNK(ip->i_di.di_mode))
  80                 return -EOPNOTSUPP;
  81         if (!access && !S_ISDIR(ip->i_di.di_mode))
  82                 return -EACCES;
  83
  84         return 0;
  85 }
  86
  87 static int acl_get(struct gfs2_inode *ip, int access, struct posix_acl **acl,
  88                    struct gfs2_ea_location *el, char **data, unsigned int *len)
  89 {
  90         struct gfs2_ea_request er;
  91         struct gfs2_ea_location el_this;
  92         int error;
  93
  94         if (!ip->i_di.di_eattr)
  95                 return 0;
  96
  97         memset(&er, 0, sizeof(struct gfs2_ea_request));
  98         if (access) {
  99                 er.er_name = GFS2_POSIX_ACL_ACCESS;
 100                 er.er_name_len = GFS2_POSIX_ACL_ACCESS_LEN;
 101         } else {
 102                 er.er_name = GFS2_POSIX_ACL_DEFAULT;
 103                 er.er_name_len = GFS2_POSIX_ACL_DEFAULT_LEN;
 104         }
 105         er.er_type = GFS2_EATYPE_SYS;
 106
 107         if (!el)
 108                 el = &el_this;
 109
 110         error = gfs2_ea_find(ip, &er, el);
 111         if (error)
 112                 return error;
 113         if (!el->el_ea)
 114                 return 0;
 115         if (!GFS2_EA_DATA_LEN(el->el_ea))
 116                 goto out;
 117
 118         er.er_data_len = GFS2_EA_DATA_LEN(el->el_ea);
 119         er.er_data = kmalloc(er.er_data_len, GFP_KERNEL);
 120         error = -ENOMEM;
 121         if (!er.er_data)
 122                 goto out;
 123
 124         error = gfs2_ea_get_copy(ip, el, er.er_data);
 125         if (error)
 126                 goto out_kfree;
 127
 128         if (acl) {
 129                 *acl = posix_acl_from_xattr(er.er_data, er.er_data_len);
 130                 if (IS_ERR(*acl))
 131                         error = PTR_ERR(*acl);
 132         }
 133
 134 out_kfree:
 135         if (error || !data)
 136                 kfree(er.er_data);
 137         else {
 138                 *data = er.er_data;
 139                 *len = er.er_data_len;
 140         }
 141 out:
 142         if (error || el == &el_this)
 143                 brelse(el->el_bh);
 144         return error;
 145 }
 146
 147 /**
 148  * gfs2_check_acl_locked - Check an ACL to see if we're allowed to do something
 149  * @inode: the file we want to do something to
 150  * @mask: what we want to do
 151  *
 152  * Returns: errno
 153  */
 154
 155 int gfs2_check_acl_locked(struct inode *inode, int mask)
 156 {
 157         struct posix_acl *acl = NULL;
 158         int error;
 159
 160         error = acl_get(GFS2_I(inode), ACL_ACCESS, &acl, NULL, NULL, NULL);
 161         if (error)
 162                 return error;
 163
 164         if (acl) {
 165                 error = posix_acl_permission(inode, acl, mask);
 166                 posix_acl_release(acl);
 167                 return error;
 168         }
 169
 170         return -EAGAIN;
 171 }
 172
 173 int gfs2_check_acl(struct inode *inode, int mask)
 174 {
 175         struct gfs2_inode *ip = GFS2_I(inode);
 176         struct gfs2_holder i_gh;
 177         int error;
 178
 179         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 180         if (!error) {
 181                 error = gfs2_check_acl_locked(inode, mask);
 182                 gfs2_glock_dq_uninit(&i_gh);
 183         }
 184
 185         return error;
 186 }
 187
 188 static int munge_mode(struct gfs2_inode *ip, mode_t mode)
 189 {
 190         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 191         struct buffer_head *dibh;
 192         int error;
 193
 194         error = gfs2_trans_begin(sdp, RES_DINODE, 0);
 195         if (error)
 196                 return error;
 197
 198         error = gfs2_meta_inode_buffer(ip, &dibh);
 199         if (!error) {
 200                 gfs2_assert_withdraw(sdp,
 201                                 (ip->i_di.di_mode & S_IFMT) == (mode & S_IFMT));
 202                 ip->i_di.di_mode = mode;
 203                 gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 204                 gfs2_dinode_out(&ip->i_di, dibh->b_data);
 205                 brelse(dibh);
 206         }
 207
 208         gfs2_trans_end(sdp);
 209
 210         return 0;
 211 }
 212
 213 int gfs2_acl_create(struct gfs2_inode *dip, struct gfs2_inode *ip)
 214 {
 215         struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
 216         struct posix_acl *acl = NULL, *clone;
 217         struct gfs2_ea_request er;
 218         mode_t mode = ip->i_di.di_mode;
 219         int error;
 220
 221         if (!sdp->sd_args.ar_posix_acl)
 222                 return 0;
 223         if (S_ISLNK(ip->i_di.di_mode))
 224                 return 0;
 225
 226         memset(&er, 0, sizeof(struct gfs2_ea_request));
 227         er.er_type = GFS2_EATYPE_SYS;
 228
 229         error = acl_get(dip, ACL_DEFAULT, &acl, NULL,
 230                         &er.er_data, &er.er_data_len);
 231         if (error)
 232                 return error;
 233         if (!acl) {
 234                 mode &= ~current->fs->umask;
 235                 if (mode != ip->i_di.di_mode)
 236                         error = munge_mode(ip, mode);
 237                 return error;
 238         }
 239
 240         clone = posix_acl_clone(acl, GFP_KERNEL);
 241         error = -ENOMEM;
 242         if (!clone)
 243                 goto out;
 244         posix_acl_release(acl);
 245         acl = clone;
 246
 247         if (S_ISDIR(ip->i_di.di_mode)) {
 248                 er.er_name = GFS2_POSIX_ACL_DEFAULT;
 249                 er.er_name_len = GFS2_POSIX_ACL_DEFAULT_LEN;
 250                 error = gfs2_system_eaops.eo_set(ip, &er);
 251                 if (error)
 252                         goto out;
 253         }
 254
 255         error = posix_acl_create_masq(acl, &mode);
 256         if (error < 0)
 257                 goto out;
 258         if (error > 0) {
 259                 er.er_name = GFS2_POSIX_ACL_ACCESS;
 260                 er.er_name_len = GFS2_POSIX_ACL_ACCESS_LEN;
 261                 posix_acl_to_xattr(acl, er.er_data, er.er_data_len);
 262                 er.er_mode = mode;
 263                 er.er_flags = GFS2_ERF_MODE;
 264                 error = gfs2_system_eaops.eo_set(ip, &er);
 265                 if (error)
 266                         goto out;
 267         } else
 268                 munge_mode(ip, mode);
 269
 270 out:
 271         posix_acl_release(acl);
 272         kfree(er.er_data);
 273         return error;
 274 }
 275
 276 int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr)
 277 {
 278         struct posix_acl *acl = NULL, *clone;
 279         struct gfs2_ea_location el;
 280         char *data;
 281         unsigned int len;
 282         int error;
 283
 284         error = acl_get(ip, ACL_ACCESS, &acl, &el, &data, &len);
 285         if (error)
 286                 return error;
 287         if (!acl)
 288                 return gfs2_setattr_simple(ip, attr);
 289
 290         clone = posix_acl_clone(acl, GFP_KERNEL);
 291         error = -ENOMEM;
 292         if (!clone)
 293                 goto out;
 294         posix_acl_release(acl);
 295         acl = clone;
 296
 297         error = posix_acl_chmod_masq(acl, attr->ia_mode);
 298         if (!error) {
 299                 posix_acl_to_xattr(acl, data, len);
 300                 error = gfs2_ea_acl_chmod(ip, &el, attr, data);
 301         }
 302
 303 out:
 304         posix_acl_release(acl);
 305         brelse(el.el_bh);
 306         kfree(data);
 307         return error;
 308 }
 309