1 /* 2 * Copyright (c) 2008, Christoph Hellwig 3 * All Rights Reserved. 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public License as 7 * published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it would be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 17 */ 18 #include "xfs.h" 19 #include "xfs_format.h" 20 #include "xfs_log_format.h" 21 #include "xfs_trans_resv.h" 22 #include "xfs_mount.h" 23 #include "xfs_inode.h" 24 #include "xfs_acl.h" 25 #include "xfs_attr.h" 26 #include "xfs_trace.h" 27 #include <linux/slab.h> 28 #include <linux/xattr.h> 29 #include <linux/posix_acl_xattr.h> 30 31 32 /* 33 * Locking scheme: 34 * - all ACL updates are protected by inode->i_mutex, which is taken before 35 * calling into this file. 36 */ 37 38 STATIC struct posix_acl * 39 xfs_acl_from_disk( 40 const struct xfs_acl *aclp, 41 int len, 42 int max_entries) 43 { 44 struct posix_acl_entry *acl_e; 45 struct posix_acl *acl; 46 const struct xfs_acl_entry *ace; 47 unsigned int count, i; 48 49 if (len < sizeof(*aclp)) 50 return ERR_PTR(-EFSCORRUPTED); 51 count = be32_to_cpu(aclp->acl_cnt); 52 if (count > max_entries || XFS_ACL_SIZE(count) != len) 53 return ERR_PTR(-EFSCORRUPTED); 54 55 acl = posix_acl_alloc(count, GFP_KERNEL); 56 if (!acl) 57 return ERR_PTR(-ENOMEM); 58 59 for (i = 0; i < count; i++) { 60 acl_e = &acl->a_entries[i]; 61 ace = &aclp->acl_entry[i]; 62 63 /* 64 * The tag is 32 bits on disk and 16 bits in core. 65 * 66 * Because every access to it goes through the core 67 * format first this is not a problem. 68 */ 69 acl_e->e_tag = be32_to_cpu(ace->ae_tag); 70 acl_e->e_perm = be16_to_cpu(ace->ae_perm); 71 72 switch (acl_e->e_tag) { 73 case ACL_USER: 74 acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id)); 75 break; 76 case ACL_GROUP: 77 acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id)); 78 break; 79 case ACL_USER_OBJ: 80 case ACL_GROUP_OBJ: 81 case ACL_MASK: 82 case ACL_OTHER: 83 break; 84 default: 85 goto fail; 86 } 87 } 88 return acl; 89 90 fail: 91 posix_acl_release(acl); 92 return ERR_PTR(-EINVAL); 93 } 94 95 STATIC void 96 xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl) 97 { 98 const struct posix_acl_entry *acl_e; 99 struct xfs_acl_entry *ace; 100 int i; 101 102 aclp->acl_cnt = cpu_to_be32(acl->a_count); 103 for (i = 0; i < acl->a_count; i++) { 104 ace = &aclp->acl_entry[i]; 105 acl_e = &acl->a_entries[i]; 106 107 ace->ae_tag = cpu_to_be32(acl_e->e_tag); 108 switch (acl_e->e_tag) { 109 case ACL_USER: 110 ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid)); 111 break; 112 case ACL_GROUP: 113 ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid)); 114 break; 115 default: 116 ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID); 117 break; 118 } 119 120 ace->ae_perm = cpu_to_be16(acl_e->e_perm); 121 } 122 } 123 124 struct posix_acl * 125 xfs_get_acl(struct inode *inode, int type) 126 { 127 struct xfs_inode *ip = XFS_I(inode); 128 struct posix_acl *acl = NULL; 129 struct xfs_acl *xfs_acl; 130 unsigned char *ea_name; 131 int error; 132 int len; 133 134 trace_xfs_get_acl(ip); 135 136 switch (type) { 137 case ACL_TYPE_ACCESS: 138 ea_name = SGI_ACL_FILE; 139 break; 140 case ACL_TYPE_DEFAULT: 141 ea_name = SGI_ACL_DEFAULT; 142 break; 143 default: 144 BUG(); 145 } 146 147 /* 148 * If we have a cached ACLs value just return it, not need to 149 * go out to the disk. 150 */ 151 len = XFS_ACL_MAX_SIZE(ip->i_mount); 152 xfs_acl = kmem_zalloc_large(len, KM_SLEEP); 153 if (!xfs_acl) 154 return ERR_PTR(-ENOMEM); 155 156 error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl, 157 &len, ATTR_ROOT); 158 if (error) { 159 /* 160 * If the attribute doesn't exist make sure we have a negative 161 * cache entry, for any other error assume it is transient and 162 * leave the cache entry as ACL_NOT_CACHED. 163 */ 164 if (error == -ENOATTR) 165 goto out_update_cache; 166 acl = ERR_PTR(error); 167 goto out; 168 } 169 170 acl = xfs_acl_from_disk(xfs_acl, len, XFS_ACL_MAX_ENTRIES(ip->i_mount)); 171 if (IS_ERR(acl)) 172 goto out; 173 174 out_update_cache: 175 set_cached_acl(inode, type, acl); 176 out: 177 kmem_free(xfs_acl); 178 return acl; 179 } 180 181 STATIC int 182 __xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl) 183 { 184 struct xfs_inode *ip = XFS_I(inode); 185 unsigned char *ea_name; 186 int error; 187 188 switch (type) { 189 case ACL_TYPE_ACCESS: 190 ea_name = SGI_ACL_FILE; 191 break; 192 case ACL_TYPE_DEFAULT: 193 if (!S_ISDIR(inode->i_mode)) 194 return acl ? -EACCES : 0; 195 ea_name = SGI_ACL_DEFAULT; 196 break; 197 default: 198 return -EINVAL; 199 } 200 201 if (acl) { 202 struct xfs_acl *xfs_acl; 203 int len = XFS_ACL_MAX_SIZE(ip->i_mount); 204 205 xfs_acl = kmem_zalloc_large(len, KM_SLEEP); 206 if (!xfs_acl) 207 return -ENOMEM; 208 209 xfs_acl_to_disk(xfs_acl, acl); 210 211 /* subtract away the unused acl entries */ 212 len -= sizeof(struct xfs_acl_entry) * 213 (XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count); 214 215 error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl, 216 len, ATTR_ROOT); 217 218 kmem_free(xfs_acl); 219 } else { 220 /* 221 * A NULL ACL argument means we want to remove the ACL. 222 */ 223 error = xfs_attr_remove(ip, ea_name, ATTR_ROOT); 224 225 /* 226 * If the attribute didn't exist to start with that's fine. 227 */ 228 if (error == -ENOATTR) 229 error = 0; 230 } 231 232 if (!error) 233 set_cached_acl(inode, type, acl); 234 return error; 235 } 236 237 static int 238 xfs_set_mode(struct inode *inode, umode_t mode) 239 { 240 int error = 0; 241 242 if (mode != inode->i_mode) { 243 struct iattr iattr; 244 245 iattr.ia_valid = ATTR_MODE | ATTR_CTIME; 246 iattr.ia_mode = mode; 247 iattr.ia_ctime = current_fs_time(inode->i_sb); 248 249 error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL); 250 } 251 252 return error; 253 } 254 255 int 256 xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) 257 { 258 int error = 0; 259 260 if (!acl) 261 goto set_acl; 262 263 error = -E2BIG; 264 if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb))) 265 return error; 266 267 if (type == ACL_TYPE_ACCESS) { 268 umode_t mode = inode->i_mode; 269 error = posix_acl_equiv_mode(acl, &mode); 270 271 if (error <= 0) { 272 acl = NULL; 273 274 if (error < 0) 275 return error; 276 } 277 278 error = xfs_set_mode(inode, mode); 279 if (error) 280 return error; 281 } 282 283 set_acl: 284 return __xfs_set_acl(inode, type, acl); 285 } 286