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. 162 */ 163 if (error != -ENOATTR) 164 acl = ERR_PTR(error); 165 } else { 166 acl = xfs_acl_from_disk(xfs_acl, len, 167 XFS_ACL_MAX_ENTRIES(ip->i_mount)); 168 } 169 kmem_free(xfs_acl); 170 return acl; 171 } 172 173 int 174 __xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) 175 { 176 struct xfs_inode *ip = XFS_I(inode); 177 unsigned char *ea_name; 178 int error; 179 180 switch (type) { 181 case ACL_TYPE_ACCESS: 182 ea_name = SGI_ACL_FILE; 183 break; 184 case ACL_TYPE_DEFAULT: 185 if (!S_ISDIR(inode->i_mode)) 186 return acl ? -EACCES : 0; 187 ea_name = SGI_ACL_DEFAULT; 188 break; 189 default: 190 return -EINVAL; 191 } 192 193 if (acl) { 194 struct xfs_acl *xfs_acl; 195 int len = XFS_ACL_MAX_SIZE(ip->i_mount); 196 197 xfs_acl = kmem_zalloc_large(len, KM_SLEEP); 198 if (!xfs_acl) 199 return -ENOMEM; 200 201 xfs_acl_to_disk(xfs_acl, acl); 202 203 /* subtract away the unused acl entries */ 204 len -= sizeof(struct xfs_acl_entry) * 205 (XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count); 206 207 error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl, 208 len, ATTR_ROOT); 209 210 kmem_free(xfs_acl); 211 } else { 212 /* 213 * A NULL ACL argument means we want to remove the ACL. 214 */ 215 error = xfs_attr_remove(ip, ea_name, ATTR_ROOT); 216 217 /* 218 * If the attribute didn't exist to start with that's fine. 219 */ 220 if (error == -ENOATTR) 221 error = 0; 222 } 223 224 if (!error) 225 set_cached_acl(inode, type, acl); 226 return error; 227 } 228 229 static int 230 xfs_set_mode(struct inode *inode, umode_t mode) 231 { 232 int error = 0; 233 234 if (mode != inode->i_mode) { 235 struct iattr iattr; 236 237 iattr.ia_valid = ATTR_MODE | ATTR_CTIME; 238 iattr.ia_mode = mode; 239 iattr.ia_ctime = current_time(inode); 240 241 error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL); 242 } 243 244 return error; 245 } 246 247 int 248 xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) 249 { 250 umode_t mode; 251 bool set_mode = false; 252 int error = 0; 253 254 if (!acl) 255 goto set_acl; 256 257 error = -E2BIG; 258 if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb))) 259 return error; 260 261 if (type == ACL_TYPE_ACCESS) { 262 error = posix_acl_update_mode(inode, &mode, &acl); 263 if (error) 264 return error; 265 set_mode = true; 266 } 267 268 set_acl: 269 error = __xfs_set_acl(inode, acl, type); 270 if (error) 271 return error; 272 273 /* 274 * We set the mode after successfully updating the ACL xattr because the 275 * xattr update can fail at ENOSPC and we don't want to change the mode 276 * if the ACL update hasn't been applied. 277 */ 278 if (set_mode) 279 error = xfs_set_mode(inode, mode); 280 281 return error; 282 } 283