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 /** 71 * gfs2_check_acl - Check an ACL to see if we're allowed to do something 72 * @inode: the file we want to do something to 73 * @mask: what we want to do 74 * 75 * Returns: errno 76 */ 77 78 int gfs2_check_acl(struct inode *inode, int mask, unsigned int flags) 79 { 80 struct posix_acl *acl; 81 int error; 82 83 if (flags & IPERM_FLAG_RCU) { 84 if (!negative_cached_acl(inode, ACL_TYPE_ACCESS)) 85 return -ECHILD; 86 return -EAGAIN; 87 } 88 89 acl = gfs2_acl_get(GFS2_I(inode), ACL_TYPE_ACCESS); 90 if (IS_ERR(acl)) 91 return PTR_ERR(acl); 92 93 if (acl) { 94 error = posix_acl_permission(inode, acl, mask); 95 posix_acl_release(acl); 96 return error; 97 } 98 99 return -EAGAIN; 100 } 101 102 static int gfs2_set_mode(struct inode *inode, mode_t mode) 103 { 104 int error = 0; 105 106 if (mode != inode->i_mode) { 107 struct iattr iattr; 108 109 iattr.ia_valid = ATTR_MODE; 110 iattr.ia_mode = mode; 111 112 error = gfs2_setattr_simple(GFS2_I(inode), &iattr); 113 } 114 115 return error; 116 } 117 118 static int gfs2_acl_set(struct inode *inode, int type, struct posix_acl *acl) 119 { 120 int error; 121 int len; 122 char *data; 123 const char *name = gfs2_acl_name(type); 124 125 BUG_ON(name == NULL); 126 len = posix_acl_to_xattr(acl, NULL, 0); 127 if (len == 0) 128 return 0; 129 data = kmalloc(len, GFP_NOFS); 130 if (data == NULL) 131 return -ENOMEM; 132 error = posix_acl_to_xattr(acl, data, len); 133 if (error < 0) 134 goto out; 135 error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS); 136 if (!error) 137 set_cached_acl(inode, type, acl); 138 out: 139 kfree(data); 140 return error; 141 } 142 143 int gfs2_acl_create(struct gfs2_inode *dip, struct inode *inode) 144 { 145 struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode); 146 struct posix_acl *acl, *clone; 147 mode_t mode = inode->i_mode; 148 int error = 0; 149 150 if (!sdp->sd_args.ar_posix_acl) 151 return 0; 152 if (S_ISLNK(inode->i_mode)) 153 return 0; 154 155 acl = gfs2_acl_get(dip, ACL_TYPE_DEFAULT); 156 if (IS_ERR(acl)) 157 return PTR_ERR(acl); 158 if (!acl) { 159 mode &= ~current_umask(); 160 if (mode != inode->i_mode) 161 error = gfs2_set_mode(inode, mode); 162 return error; 163 } 164 165 if (S_ISDIR(inode->i_mode)) { 166 error = gfs2_acl_set(inode, ACL_TYPE_DEFAULT, acl); 167 if (error) 168 goto out; 169 } 170 171 clone = posix_acl_clone(acl, GFP_NOFS); 172 error = -ENOMEM; 173 if (!clone) 174 goto out; 175 posix_acl_release(acl); 176 acl = clone; 177 178 error = posix_acl_create_masq(acl, &mode); 179 if (error < 0) 180 goto out; 181 if (error == 0) 182 goto munge; 183 184 error = gfs2_acl_set(inode, ACL_TYPE_ACCESS, acl); 185 if (error) 186 goto out; 187 munge: 188 error = gfs2_set_mode(inode, mode); 189 out: 190 posix_acl_release(acl); 191 return error; 192 } 193 194 int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr) 195 { 196 struct posix_acl *acl, *clone; 197 char *data; 198 unsigned int len; 199 int error; 200 201 acl = gfs2_acl_get(ip, ACL_TYPE_ACCESS); 202 if (IS_ERR(acl)) 203 return PTR_ERR(acl); 204 if (!acl) 205 return gfs2_setattr_simple(ip, attr); 206 207 clone = posix_acl_clone(acl, GFP_NOFS); 208 error = -ENOMEM; 209 if (!clone) 210 goto out; 211 posix_acl_release(acl); 212 acl = clone; 213 214 error = posix_acl_chmod_masq(acl, attr->ia_mode); 215 if (!error) { 216 len = posix_acl_to_xattr(acl, NULL, 0); 217 data = kmalloc(len, GFP_NOFS); 218 error = -ENOMEM; 219 if (data == NULL) 220 goto out; 221 posix_acl_to_xattr(acl, data, len); 222 error = gfs2_xattr_acl_chmod(ip, attr, data); 223 kfree(data); 224 set_cached_acl(&ip->i_inode, ACL_TYPE_ACCESS, acl); 225 } 226 227 out: 228 posix_acl_release(acl); 229 return error; 230 } 231 232 static int gfs2_acl_type(const char *name) 233 { 234 if (strcmp(name, GFS2_POSIX_ACL_ACCESS) == 0) 235 return ACL_TYPE_ACCESS; 236 if (strcmp(name, GFS2_POSIX_ACL_DEFAULT) == 0) 237 return ACL_TYPE_DEFAULT; 238 return -EINVAL; 239 } 240 241 static int gfs2_xattr_system_get(struct dentry *dentry, const char *name, 242 void *buffer, size_t size, int xtype) 243 { 244 struct inode *inode = dentry->d_inode; 245 struct gfs2_sbd *sdp = GFS2_SB(inode); 246 struct posix_acl *acl; 247 int type; 248 int error; 249 250 if (!sdp->sd_args.ar_posix_acl) 251 return -EOPNOTSUPP; 252 253 type = gfs2_acl_type(name); 254 if (type < 0) 255 return type; 256 257 acl = gfs2_acl_get(GFS2_I(inode), type); 258 if (IS_ERR(acl)) 259 return PTR_ERR(acl); 260 if (acl == NULL) 261 return -ENODATA; 262 263 error = posix_acl_to_xattr(acl, buffer, size); 264 posix_acl_release(acl); 265 266 return error; 267 } 268 269 static int gfs2_xattr_system_set(struct dentry *dentry, const char *name, 270 const void *value, size_t size, int flags, 271 int xtype) 272 { 273 struct inode *inode = dentry->d_inode; 274 struct gfs2_sbd *sdp = GFS2_SB(inode); 275 struct posix_acl *acl = NULL; 276 int error = 0, type; 277 278 if (!sdp->sd_args.ar_posix_acl) 279 return -EOPNOTSUPP; 280 281 type = gfs2_acl_type(name); 282 if (type < 0) 283 return type; 284 if (flags & XATTR_CREATE) 285 return -EINVAL; 286 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) 287 return value ? -EACCES : 0; 288 if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER)) 289 return -EPERM; 290 if (S_ISLNK(inode->i_mode)) 291 return -EOPNOTSUPP; 292 293 if (!value) 294 goto set_acl; 295 296 acl = posix_acl_from_xattr(value, size); 297 if (!acl) { 298 /* 299 * acl_set_file(3) may request that we set default ACLs with 300 * zero length -- defend (gracefully) against that here. 301 */ 302 goto out; 303 } 304 if (IS_ERR(acl)) { 305 error = PTR_ERR(acl); 306 goto out; 307 } 308 309 error = posix_acl_valid(acl); 310 if (error) 311 goto out_release; 312 313 error = -EINVAL; 314 if (acl->a_count > GFS2_ACL_MAX_ENTRIES) 315 goto out_release; 316 317 if (type == ACL_TYPE_ACCESS) { 318 mode_t mode = inode->i_mode; 319 error = posix_acl_equiv_mode(acl, &mode); 320 321 if (error <= 0) { 322 posix_acl_release(acl); 323 acl = NULL; 324 325 if (error < 0) 326 return error; 327 } 328 329 error = gfs2_set_mode(inode, mode); 330 if (error) 331 goto out_release; 332 } 333 334 set_acl: 335 error = __gfs2_xattr_set(inode, name, value, size, 0, GFS2_EATYPE_SYS); 336 if (!error) { 337 if (acl) 338 set_cached_acl(inode, type, acl); 339 else 340 forget_cached_acl(inode, type); 341 } 342 out_release: 343 posix_acl_release(acl); 344 out: 345 return error; 346 } 347 348 const struct xattr_handler gfs2_xattr_system_handler = { 349 .prefix = XATTR_SYSTEM_PREFIX, 350 .flags = GFS2_EATYPE_SYS, 351 .get = gfs2_xattr_system_get, 352 .set = gfs2_xattr_system_set, 353 }; 354 355