1 /* 2 * linux/fs/ext4/acl.c 3 * 4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de> 5 */ 6 7 #include <linux/quotaops.h> 8 #include "ext4_jbd2.h" 9 #include "ext4.h" 10 #include "xattr.h" 11 #include "acl.h" 12 13 /* 14 * Convert from filesystem to in-memory representation. 15 */ 16 static struct posix_acl * 17 ext4_acl_from_disk(const void *value, size_t size) 18 { 19 const char *end = (char *)value + size; 20 int n, count; 21 struct posix_acl *acl; 22 23 if (!value) 24 return NULL; 25 if (size < sizeof(ext4_acl_header)) 26 return ERR_PTR(-EINVAL); 27 if (((ext4_acl_header *)value)->a_version != 28 cpu_to_le32(EXT4_ACL_VERSION)) 29 return ERR_PTR(-EINVAL); 30 value = (char *)value + sizeof(ext4_acl_header); 31 count = ext4_acl_count(size); 32 if (count < 0) 33 return ERR_PTR(-EINVAL); 34 if (count == 0) 35 return NULL; 36 acl = posix_acl_alloc(count, GFP_NOFS); 37 if (!acl) 38 return ERR_PTR(-ENOMEM); 39 for (n = 0; n < count; n++) { 40 ext4_acl_entry *entry = 41 (ext4_acl_entry *)value; 42 if ((char *)value + sizeof(ext4_acl_entry_short) > end) 43 goto fail; 44 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag); 45 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm); 46 47 switch (acl->a_entries[n].e_tag) { 48 case ACL_USER_OBJ: 49 case ACL_GROUP_OBJ: 50 case ACL_MASK: 51 case ACL_OTHER: 52 value = (char *)value + 53 sizeof(ext4_acl_entry_short); 54 break; 55 56 case ACL_USER: 57 value = (char *)value + sizeof(ext4_acl_entry); 58 if ((char *)value > end) 59 goto fail; 60 acl->a_entries[n].e_uid = 61 make_kuid(&init_user_ns, 62 le32_to_cpu(entry->e_id)); 63 break; 64 case ACL_GROUP: 65 value = (char *)value + sizeof(ext4_acl_entry); 66 if ((char *)value > end) 67 goto fail; 68 acl->a_entries[n].e_gid = 69 make_kgid(&init_user_ns, 70 le32_to_cpu(entry->e_id)); 71 break; 72 73 default: 74 goto fail; 75 } 76 } 77 if (value != end) 78 goto fail; 79 return acl; 80 81 fail: 82 posix_acl_release(acl); 83 return ERR_PTR(-EINVAL); 84 } 85 86 /* 87 * Convert from in-memory to filesystem representation. 88 */ 89 static void * 90 ext4_acl_to_disk(const struct posix_acl *acl, size_t *size) 91 { 92 ext4_acl_header *ext_acl; 93 char *e; 94 size_t n; 95 96 *size = ext4_acl_size(acl->a_count); 97 ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count * 98 sizeof(ext4_acl_entry), GFP_NOFS); 99 if (!ext_acl) 100 return ERR_PTR(-ENOMEM); 101 ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION); 102 e = (char *)ext_acl + sizeof(ext4_acl_header); 103 for (n = 0; n < acl->a_count; n++) { 104 const struct posix_acl_entry *acl_e = &acl->a_entries[n]; 105 ext4_acl_entry *entry = (ext4_acl_entry *)e; 106 entry->e_tag = cpu_to_le16(acl_e->e_tag); 107 entry->e_perm = cpu_to_le16(acl_e->e_perm); 108 switch (acl_e->e_tag) { 109 case ACL_USER: 110 entry->e_id = cpu_to_le32( 111 from_kuid(&init_user_ns, acl_e->e_uid)); 112 e += sizeof(ext4_acl_entry); 113 break; 114 case ACL_GROUP: 115 entry->e_id = cpu_to_le32( 116 from_kgid(&init_user_ns, acl_e->e_gid)); 117 e += sizeof(ext4_acl_entry); 118 break; 119 120 case ACL_USER_OBJ: 121 case ACL_GROUP_OBJ: 122 case ACL_MASK: 123 case ACL_OTHER: 124 e += sizeof(ext4_acl_entry_short); 125 break; 126 127 default: 128 goto fail; 129 } 130 } 131 return (char *)ext_acl; 132 133 fail: 134 kfree(ext_acl); 135 return ERR_PTR(-EINVAL); 136 } 137 138 /* 139 * Inode operation get_posix_acl(). 140 * 141 * inode->i_mutex: don't care 142 */ 143 struct posix_acl * 144 ext4_get_acl(struct inode *inode, int type) 145 { 146 int name_index; 147 char *value = NULL; 148 struct posix_acl *acl; 149 int retval; 150 151 switch (type) { 152 case ACL_TYPE_ACCESS: 153 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS; 154 break; 155 case ACL_TYPE_DEFAULT: 156 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT; 157 break; 158 default: 159 BUG(); 160 } 161 retval = ext4_xattr_get(inode, name_index, "", NULL, 0); 162 if (retval > 0) { 163 value = kmalloc(retval, GFP_NOFS); 164 if (!value) 165 return ERR_PTR(-ENOMEM); 166 retval = ext4_xattr_get(inode, name_index, "", value, retval); 167 } 168 if (retval > 0) 169 acl = ext4_acl_from_disk(value, retval); 170 else if (retval == -ENODATA || retval == -ENOSYS) 171 acl = NULL; 172 else 173 acl = ERR_PTR(retval); 174 kfree(value); 175 176 return acl; 177 } 178 179 /* 180 * Set the access or default ACL of an inode. 181 * 182 * inode->i_mutex: down unless called from ext4_new_inode 183 */ 184 static int 185 __ext4_set_acl(handle_t *handle, struct inode *inode, int type, 186 struct posix_acl *acl, int xattr_flags) 187 { 188 int name_index; 189 void *value = NULL; 190 size_t size = 0; 191 int error; 192 193 switch (type) { 194 case ACL_TYPE_ACCESS: 195 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS; 196 if (acl) { 197 error = posix_acl_update_mode(inode, &inode->i_mode, &acl); 198 if (error) 199 return error; 200 inode->i_ctime = current_time(inode); 201 ext4_mark_inode_dirty(handle, inode); 202 } 203 break; 204 205 case ACL_TYPE_DEFAULT: 206 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT; 207 if (!S_ISDIR(inode->i_mode)) 208 return acl ? -EACCES : 0; 209 break; 210 211 default: 212 return -EINVAL; 213 } 214 if (acl) { 215 value = ext4_acl_to_disk(acl, &size); 216 if (IS_ERR(value)) 217 return (int)PTR_ERR(value); 218 } 219 220 error = ext4_xattr_set_handle(handle, inode, name_index, "", 221 value, size, xattr_flags); 222 223 kfree(value); 224 if (!error) 225 set_cached_acl(inode, type, acl); 226 227 return error; 228 } 229 230 int 231 ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type) 232 { 233 handle_t *handle; 234 int error, credits, retries = 0; 235 size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0; 236 237 error = dquot_initialize(inode); 238 if (error) 239 return error; 240 retry: 241 error = ext4_xattr_set_credits(inode, acl_size, false /* is_create */, 242 &credits); 243 if (error) 244 return error; 245 246 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits); 247 if (IS_ERR(handle)) 248 return PTR_ERR(handle); 249 250 error = __ext4_set_acl(handle, inode, type, acl, 0 /* xattr_flags */); 251 ext4_journal_stop(handle); 252 if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) 253 goto retry; 254 return error; 255 } 256 257 /* 258 * Initialize the ACLs of a new inode. Called from ext4_new_inode. 259 * 260 * dir->i_mutex: down 261 * inode->i_mutex: up (access to inode is still exclusive) 262 */ 263 int 264 ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir) 265 { 266 struct posix_acl *default_acl, *acl; 267 int error; 268 269 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); 270 if (error) 271 return error; 272 273 if (default_acl) { 274 error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT, 275 default_acl, XATTR_CREATE); 276 posix_acl_release(default_acl); 277 } 278 if (acl) { 279 if (!error) 280 error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, 281 acl, XATTR_CREATE); 282 posix_acl_release(acl); 283 } 284 return error; 285 } 286