1 /* 2 * Copyright IBM Corporation, 2010 3 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of version 2.1 of the GNU Lesser General Public License 7 * as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it would be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 12 * 13 */ 14 15 #include <linux/module.h> 16 #include <linux/fs.h> 17 #include <net/9p/9p.h> 18 #include <net/9p/client.h> 19 #include <linux/slab.h> 20 #include <linux/sched.h> 21 #include <linux/posix_acl_xattr.h> 22 #include "xattr.h" 23 #include "acl.h" 24 #include "v9fs.h" 25 #include "v9fs_vfs.h" 26 #include "fid.h" 27 28 static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name) 29 { 30 ssize_t size; 31 void *value = NULL; 32 struct posix_acl *acl = NULL; 33 34 size = v9fs_fid_xattr_get(fid, name, NULL, 0); 35 if (size > 0) { 36 value = kzalloc(size, GFP_NOFS); 37 if (!value) 38 return ERR_PTR(-ENOMEM); 39 size = v9fs_fid_xattr_get(fid, name, value, size); 40 if (size > 0) { 41 acl = posix_acl_from_xattr(&init_user_ns, value, size); 42 if (IS_ERR(acl)) 43 goto err_out; 44 } 45 } else if (size == -ENODATA || size == 0 || 46 size == -ENOSYS || size == -EOPNOTSUPP) { 47 acl = NULL; 48 } else 49 acl = ERR_PTR(-EIO); 50 51 err_out: 52 kfree(value); 53 return acl; 54 } 55 56 int v9fs_get_acl(struct inode *inode, struct p9_fid *fid) 57 { 58 int retval = 0; 59 struct posix_acl *pacl, *dacl; 60 struct v9fs_session_info *v9ses; 61 62 v9ses = v9fs_inode2v9ses(inode); 63 if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) || 64 ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) { 65 set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL); 66 set_cached_acl(inode, ACL_TYPE_ACCESS, NULL); 67 return 0; 68 } 69 /* get the default/access acl values and cache them */ 70 dacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_DEFAULT); 71 pacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_ACCESS); 72 73 if (!IS_ERR(dacl) && !IS_ERR(pacl)) { 74 set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl); 75 set_cached_acl(inode, ACL_TYPE_ACCESS, pacl); 76 } else 77 retval = -EIO; 78 79 if (!IS_ERR(dacl)) 80 posix_acl_release(dacl); 81 82 if (!IS_ERR(pacl)) 83 posix_acl_release(pacl); 84 85 return retval; 86 } 87 88 static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type) 89 { 90 struct posix_acl *acl; 91 /* 92 * 9p Always cache the acl value when 93 * instantiating the inode (v9fs_inode_from_fid) 94 */ 95 acl = get_cached_acl(inode, type); 96 BUG_ON(is_uncached_acl(acl)); 97 return acl; 98 } 99 100 struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type) 101 { 102 struct v9fs_session_info *v9ses; 103 104 v9ses = v9fs_inode2v9ses(inode); 105 if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) || 106 ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) { 107 /* 108 * On access = client and acl = on mode get the acl 109 * values from the server 110 */ 111 return NULL; 112 } 113 return v9fs_get_cached_acl(inode, type); 114 115 } 116 117 static int v9fs_set_acl(struct p9_fid *fid, int type, struct posix_acl *acl) 118 { 119 int retval; 120 char *name; 121 size_t size; 122 void *buffer; 123 if (!acl) 124 return 0; 125 126 /* Set a setxattr request to server */ 127 size = posix_acl_xattr_size(acl->a_count); 128 buffer = kmalloc(size, GFP_KERNEL); 129 if (!buffer) 130 return -ENOMEM; 131 retval = posix_acl_to_xattr(&init_user_ns, acl, buffer, size); 132 if (retval < 0) 133 goto err_free_out; 134 switch (type) { 135 case ACL_TYPE_ACCESS: 136 name = XATTR_NAME_POSIX_ACL_ACCESS; 137 break; 138 case ACL_TYPE_DEFAULT: 139 name = XATTR_NAME_POSIX_ACL_DEFAULT; 140 break; 141 default: 142 BUG(); 143 } 144 retval = v9fs_fid_xattr_set(fid, name, buffer, size, 0); 145 err_free_out: 146 kfree(buffer); 147 return retval; 148 } 149 150 int v9fs_acl_chmod(struct inode *inode, struct p9_fid *fid) 151 { 152 int retval = 0; 153 struct posix_acl *acl; 154 155 if (S_ISLNK(inode->i_mode)) 156 return -EOPNOTSUPP; 157 acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS); 158 if (acl) { 159 retval = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode); 160 if (retval) 161 return retval; 162 set_cached_acl(inode, ACL_TYPE_ACCESS, acl); 163 retval = v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl); 164 posix_acl_release(acl); 165 } 166 return retval; 167 } 168 169 int v9fs_set_create_acl(struct inode *inode, struct p9_fid *fid, 170 struct posix_acl *dacl, struct posix_acl *acl) 171 { 172 set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl); 173 set_cached_acl(inode, ACL_TYPE_ACCESS, acl); 174 v9fs_set_acl(fid, ACL_TYPE_DEFAULT, dacl); 175 v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl); 176 return 0; 177 } 178 179 void v9fs_put_acl(struct posix_acl *dacl, 180 struct posix_acl *acl) 181 { 182 posix_acl_release(dacl); 183 posix_acl_release(acl); 184 } 185 186 int v9fs_acl_mode(struct inode *dir, umode_t *modep, 187 struct posix_acl **dpacl, struct posix_acl **pacl) 188 { 189 int retval = 0; 190 umode_t mode = *modep; 191 struct posix_acl *acl = NULL; 192 193 if (!S_ISLNK(mode)) { 194 acl = v9fs_get_cached_acl(dir, ACL_TYPE_DEFAULT); 195 if (IS_ERR(acl)) 196 return PTR_ERR(acl); 197 if (!acl) 198 mode &= ~current_umask(); 199 } 200 if (acl) { 201 if (S_ISDIR(mode)) 202 *dpacl = posix_acl_dup(acl); 203 retval = __posix_acl_create(&acl, GFP_NOFS, &mode); 204 if (retval < 0) 205 return retval; 206 if (retval > 0) 207 *pacl = acl; 208 else 209 posix_acl_release(acl); 210 } 211 *modep = mode; 212 return 0; 213 } 214 215 static int v9fs_xattr_get_acl(const struct xattr_handler *handler, 216 struct dentry *dentry, struct inode *inode, 217 const char *name, void *buffer, size_t size) 218 { 219 struct v9fs_session_info *v9ses; 220 struct posix_acl *acl; 221 int error; 222 223 v9ses = v9fs_dentry2v9ses(dentry); 224 /* 225 * We allow set/get/list of acl when access=client is not specified 226 */ 227 if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) 228 return v9fs_xattr_get(dentry, handler->name, buffer, size); 229 230 acl = v9fs_get_cached_acl(inode, handler->flags); 231 if (IS_ERR(acl)) 232 return PTR_ERR(acl); 233 if (acl == NULL) 234 return -ENODATA; 235 error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size); 236 posix_acl_release(acl); 237 238 return error; 239 } 240 241 static int v9fs_xattr_set_acl(const struct xattr_handler *handler, 242 struct user_namespace *mnt_userns, 243 struct dentry *dentry, struct inode *inode, 244 const char *name, const void *value, 245 size_t size, int flags) 246 { 247 int retval; 248 struct posix_acl *acl; 249 struct v9fs_session_info *v9ses; 250 251 v9ses = v9fs_dentry2v9ses(dentry); 252 /* 253 * set the attribute on the remote. Without even looking at the 254 * xattr value. We leave it to the server to validate 255 */ 256 if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) 257 return v9fs_xattr_set(dentry, handler->name, value, size, 258 flags); 259 260 if (S_ISLNK(inode->i_mode)) 261 return -EOPNOTSUPP; 262 if (!inode_owner_or_capable(&init_user_ns, inode)) 263 return -EPERM; 264 if (value) { 265 /* update the cached acl value */ 266 acl = posix_acl_from_xattr(&init_user_ns, value, size); 267 if (IS_ERR(acl)) 268 return PTR_ERR(acl); 269 else if (acl) { 270 retval = posix_acl_valid(inode->i_sb->s_user_ns, acl); 271 if (retval) 272 goto err_out; 273 } 274 } else 275 acl = NULL; 276 277 switch (handler->flags) { 278 case ACL_TYPE_ACCESS: 279 if (acl) { 280 struct iattr iattr = { 0 }; 281 struct posix_acl *old_acl = acl; 282 283 retval = posix_acl_update_mode(&init_user_ns, inode, 284 &iattr.ia_mode, &acl); 285 if (retval) 286 goto err_out; 287 if (!acl) { 288 /* 289 * ACL can be represented 290 * by the mode bits. So don't 291 * update ACL. 292 */ 293 posix_acl_release(old_acl); 294 value = NULL; 295 size = 0; 296 } 297 iattr.ia_valid = ATTR_MODE; 298 /* FIXME should we update ctime ? 299 * What is the following setxattr update the 300 * mode ? 301 */ 302 v9fs_vfs_setattr_dotl(&init_user_ns, dentry, &iattr); 303 } 304 break; 305 case ACL_TYPE_DEFAULT: 306 if (!S_ISDIR(inode->i_mode)) { 307 retval = acl ? -EINVAL : 0; 308 goto err_out; 309 } 310 break; 311 default: 312 BUG(); 313 } 314 retval = v9fs_xattr_set(dentry, handler->name, value, size, flags); 315 if (!retval) 316 set_cached_acl(inode, handler->flags, acl); 317 err_out: 318 posix_acl_release(acl); 319 return retval; 320 } 321 322 const struct xattr_handler v9fs_xattr_acl_access_handler = { 323 .name = XATTR_NAME_POSIX_ACL_ACCESS, 324 .flags = ACL_TYPE_ACCESS, 325 .get = v9fs_xattr_get_acl, 326 .set = v9fs_xattr_set_acl, 327 }; 328 329 const struct xattr_handler v9fs_xattr_acl_default_handler = { 330 .name = XATTR_NAME_POSIX_ACL_DEFAULT, 331 .flags = ACL_TYPE_DEFAULT, 332 .get = v9fs_xattr_get_acl, 333 .set = v9fs_xattr_set_acl, 334 }; 335