1 /* 2 * linux/fs/ext4/acl.c 3 * 4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de> 5 */ 6 7 #include <linux/init.h> 8 #include <linux/sched.h> 9 #include <linux/slab.h> 10 #include <linux/capability.h> 11 #include <linux/fs.h> 12 #include "ext4_jbd2.h" 13 #include "ext4.h" 14 #include "xattr.h" 15 #include "acl.h" 16 17 /* 18 * Convert from filesystem to in-memory representation. 19 */ 20 static struct posix_acl * 21 ext4_acl_from_disk(const void *value, size_t size) 22 { 23 const char *end = (char *)value + size; 24 int n, count; 25 struct posix_acl *acl; 26 27 if (!value) 28 return NULL; 29 if (size < sizeof(ext4_acl_header)) 30 return ERR_PTR(-EINVAL); 31 if (((ext4_acl_header *)value)->a_version != 32 cpu_to_le32(EXT4_ACL_VERSION)) 33 return ERR_PTR(-EINVAL); 34 value = (char *)value + sizeof(ext4_acl_header); 35 count = ext4_acl_count(size); 36 if (count < 0) 37 return ERR_PTR(-EINVAL); 38 if (count == 0) 39 return NULL; 40 acl = posix_acl_alloc(count, GFP_NOFS); 41 if (!acl) 42 return ERR_PTR(-ENOMEM); 43 for (n = 0; n < count; n++) { 44 ext4_acl_entry *entry = 45 (ext4_acl_entry *)value; 46 if ((char *)value + sizeof(ext4_acl_entry_short) > end) 47 goto fail; 48 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag); 49 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm); 50 51 switch (acl->a_entries[n].e_tag) { 52 case ACL_USER_OBJ: 53 case ACL_GROUP_OBJ: 54 case ACL_MASK: 55 case ACL_OTHER: 56 value = (char *)value + 57 sizeof(ext4_acl_entry_short); 58 break; 59 60 case ACL_USER: 61 value = (char *)value + sizeof(ext4_acl_entry); 62 if ((char *)value > end) 63 goto fail; 64 acl->a_entries[n].e_uid = 65 make_kuid(&init_user_ns, 66 le32_to_cpu(entry->e_id)); 67 break; 68 case ACL_GROUP: 69 value = (char *)value + sizeof(ext4_acl_entry); 70 if ((char *)value > end) 71 goto fail; 72 acl->a_entries[n].e_gid = 73 make_kgid(&init_user_ns, 74 le32_to_cpu(entry->e_id)); 75 break; 76 77 default: 78 goto fail; 79 } 80 } 81 if (value != end) 82 goto fail; 83 return acl; 84 85 fail: 86 posix_acl_release(acl); 87 return ERR_PTR(-EINVAL); 88 } 89 90 /* 91 * Convert from in-memory to filesystem representation. 92 */ 93 static void * 94 ext4_acl_to_disk(const struct posix_acl *acl, size_t *size) 95 { 96 ext4_acl_header *ext_acl; 97 char *e; 98 size_t n; 99 100 *size = ext4_acl_size(acl->a_count); 101 ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count * 102 sizeof(ext4_acl_entry), GFP_NOFS); 103 if (!ext_acl) 104 return ERR_PTR(-ENOMEM); 105 ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION); 106 e = (char *)ext_acl + sizeof(ext4_acl_header); 107 for (n = 0; n < acl->a_count; n++) { 108 const struct posix_acl_entry *acl_e = &acl->a_entries[n]; 109 ext4_acl_entry *entry = (ext4_acl_entry *)e; 110 entry->e_tag = cpu_to_le16(acl_e->e_tag); 111 entry->e_perm = cpu_to_le16(acl_e->e_perm); 112 switch (acl_e->e_tag) { 113 case ACL_USER: 114 entry->e_id = cpu_to_le32( 115 from_kuid(&init_user_ns, acl_e->e_uid)); 116 e += sizeof(ext4_acl_entry); 117 break; 118 case ACL_GROUP: 119 entry->e_id = cpu_to_le32( 120 from_kgid(&init_user_ns, acl_e->e_gid)); 121 e += sizeof(ext4_acl_entry); 122 break; 123 124 case ACL_USER_OBJ: 125 case ACL_GROUP_OBJ: 126 case ACL_MASK: 127 case ACL_OTHER: 128 e += sizeof(ext4_acl_entry_short); 129 break; 130 131 default: 132 goto fail; 133 } 134 } 135 return (char *)ext_acl; 136 137 fail: 138 kfree(ext_acl); 139 return ERR_PTR(-EINVAL); 140 } 141 142 /* 143 * Inode operation get_posix_acl(). 144 * 145 * inode->i_mutex: don't care 146 */ 147 struct posix_acl * 148 ext4_get_acl(struct inode *inode, int type) 149 { 150 int name_index; 151 char *value = NULL; 152 struct posix_acl *acl; 153 int retval; 154 155 switch (type) { 156 case ACL_TYPE_ACCESS: 157 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS; 158 break; 159 case ACL_TYPE_DEFAULT: 160 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT; 161 break; 162 default: 163 BUG(); 164 } 165 retval = ext4_xattr_get(inode, name_index, "", NULL, 0); 166 if (retval > 0) { 167 value = kmalloc(retval, GFP_NOFS); 168 if (!value) 169 return ERR_PTR(-ENOMEM); 170 retval = ext4_xattr_get(inode, name_index, "", value, retval); 171 } 172 if (retval > 0) 173 acl = ext4_acl_from_disk(value, retval); 174 else if (retval == -ENODATA || retval == -ENOSYS) 175 acl = NULL; 176 else 177 acl = ERR_PTR(retval); 178 kfree(value); 179 180 if (!IS_ERR(acl)) 181 set_cached_acl(inode, type, acl); 182 183 return acl; 184 } 185 186 /* 187 * Set the access or default ACL of an inode. 188 * 189 * inode->i_mutex: down unless called from ext4_new_inode 190 */ 191 static int 192 __ext4_set_acl(handle_t *handle, struct inode *inode, int type, 193 struct posix_acl *acl) 194 { 195 int name_index; 196 void *value = NULL; 197 size_t size = 0; 198 int error; 199 200 switch (type) { 201 case ACL_TYPE_ACCESS: 202 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS; 203 if (acl) { 204 error = posix_acl_equiv_mode(acl, &inode->i_mode); 205 if (error < 0) 206 return error; 207 else { 208 inode->i_ctime = ext4_current_time(inode); 209 ext4_mark_inode_dirty(handle, inode); 210 if (error == 0) 211 acl = NULL; 212 } 213 } 214 break; 215 216 case ACL_TYPE_DEFAULT: 217 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT; 218 if (!S_ISDIR(inode->i_mode)) 219 return acl ? -EACCES : 0; 220 break; 221 222 default: 223 return -EINVAL; 224 } 225 if (acl) { 226 value = ext4_acl_to_disk(acl, &size); 227 if (IS_ERR(value)) 228 return (int)PTR_ERR(value); 229 } 230 231 error = ext4_xattr_set_handle(handle, inode, name_index, "", 232 value, size, 0); 233 234 kfree(value); 235 if (!error) 236 set_cached_acl(inode, type, acl); 237 238 return error; 239 } 240 241 int 242 ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type) 243 { 244 handle_t *handle; 245 int error, retries = 0; 246 247 retry: 248 handle = ext4_journal_start(inode, EXT4_HT_XATTR, 249 ext4_jbd2_credits_xattr(inode)); 250 if (IS_ERR(handle)) 251 return PTR_ERR(handle); 252 253 error = __ext4_set_acl(handle, inode, type, acl); 254 ext4_journal_stop(handle); 255 if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) 256 goto retry; 257 return error; 258 } 259 260 /* 261 * Initialize the ACLs of a new inode. Called from ext4_new_inode. 262 * 263 * dir->i_mutex: down 264 * inode->i_mutex: up (access to inode is still exclusive) 265 */ 266 int 267 ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir) 268 { 269 struct posix_acl *default_acl, *acl; 270 int error; 271 272 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); 273 if (error) 274 return error; 275 276 if (default_acl) { 277 error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT, 278 default_acl); 279 posix_acl_release(default_acl); 280 } 281 if (acl) { 282 if (!error) 283 error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, 284 acl); 285 posix_acl_release(acl); 286 } 287 return error; 288 } 289