1 /* 2 * linux/fs/ext2/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/fs.h> 11 #include "ext2.h" 12 #include "xattr.h" 13 #include "acl.h" 14 15 /* 16 * Convert from filesystem to in-memory representation. 17 */ 18 static struct posix_acl * 19 ext2_acl_from_disk(const void *value, size_t size) 20 { 21 const char *end = (char *)value + size; 22 int n, count; 23 struct posix_acl *acl; 24 25 if (!value) 26 return NULL; 27 if (size < sizeof(ext2_acl_header)) 28 return ERR_PTR(-EINVAL); 29 if (((ext2_acl_header *)value)->a_version != 30 cpu_to_le32(EXT2_ACL_VERSION)) 31 return ERR_PTR(-EINVAL); 32 value = (char *)value + sizeof(ext2_acl_header); 33 count = ext2_acl_count(size); 34 if (count < 0) 35 return ERR_PTR(-EINVAL); 36 if (count == 0) 37 return NULL; 38 acl = posix_acl_alloc(count, GFP_KERNEL); 39 if (!acl) 40 return ERR_PTR(-ENOMEM); 41 for (n=0; n < count; n++) { 42 ext2_acl_entry *entry = 43 (ext2_acl_entry *)value; 44 if ((char *)value + sizeof(ext2_acl_entry_short) > end) 45 goto fail; 46 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag); 47 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm); 48 switch(acl->a_entries[n].e_tag) { 49 case ACL_USER_OBJ: 50 case ACL_GROUP_OBJ: 51 case ACL_MASK: 52 case ACL_OTHER: 53 value = (char *)value + 54 sizeof(ext2_acl_entry_short); 55 break; 56 57 case ACL_USER: 58 value = (char *)value + sizeof(ext2_acl_entry); 59 if ((char *)value > end) 60 goto fail; 61 acl->a_entries[n].e_uid = 62 make_kuid(&init_user_ns, 63 le32_to_cpu(entry->e_id)); 64 break; 65 case ACL_GROUP: 66 value = (char *)value + sizeof(ext2_acl_entry); 67 if ((char *)value > end) 68 goto fail; 69 acl->a_entries[n].e_gid = 70 make_kgid(&init_user_ns, 71 le32_to_cpu(entry->e_id)); 72 break; 73 74 default: 75 goto fail; 76 } 77 } 78 if (value != end) 79 goto fail; 80 return acl; 81 82 fail: 83 posix_acl_release(acl); 84 return ERR_PTR(-EINVAL); 85 } 86 87 /* 88 * Convert from in-memory to filesystem representation. 89 */ 90 static void * 91 ext2_acl_to_disk(const struct posix_acl *acl, size_t *size) 92 { 93 ext2_acl_header *ext_acl; 94 char *e; 95 size_t n; 96 97 *size = ext2_acl_size(acl->a_count); 98 ext_acl = kmalloc(sizeof(ext2_acl_header) + acl->a_count * 99 sizeof(ext2_acl_entry), GFP_KERNEL); 100 if (!ext_acl) 101 return ERR_PTR(-ENOMEM); 102 ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION); 103 e = (char *)ext_acl + sizeof(ext2_acl_header); 104 for (n=0; n < acl->a_count; n++) { 105 const struct posix_acl_entry *acl_e = &acl->a_entries[n]; 106 ext2_acl_entry *entry = (ext2_acl_entry *)e; 107 entry->e_tag = cpu_to_le16(acl_e->e_tag); 108 entry->e_perm = cpu_to_le16(acl_e->e_perm); 109 switch(acl_e->e_tag) { 110 case ACL_USER: 111 entry->e_id = cpu_to_le32( 112 from_kuid(&init_user_ns, acl_e->e_uid)); 113 e += sizeof(ext2_acl_entry); 114 break; 115 case ACL_GROUP: 116 entry->e_id = cpu_to_le32( 117 from_kgid(&init_user_ns, acl_e->e_gid)); 118 e += sizeof(ext2_acl_entry); 119 break; 120 121 case ACL_USER_OBJ: 122 case ACL_GROUP_OBJ: 123 case ACL_MASK: 124 case ACL_OTHER: 125 e += sizeof(ext2_acl_entry_short); 126 break; 127 128 default: 129 goto fail; 130 } 131 } 132 return (char *)ext_acl; 133 134 fail: 135 kfree(ext_acl); 136 return ERR_PTR(-EINVAL); 137 } 138 139 /* 140 * inode->i_mutex: don't care 141 */ 142 struct posix_acl * 143 ext2_get_acl(struct inode *inode, int type) 144 { 145 int name_index; 146 char *value = NULL; 147 struct posix_acl *acl; 148 int retval; 149 150 switch (type) { 151 case ACL_TYPE_ACCESS: 152 name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS; 153 break; 154 case ACL_TYPE_DEFAULT: 155 name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT; 156 break; 157 default: 158 BUG(); 159 } 160 retval = ext2_xattr_get(inode, name_index, "", NULL, 0); 161 if (retval > 0) { 162 value = kmalloc(retval, GFP_KERNEL); 163 if (!value) 164 return ERR_PTR(-ENOMEM); 165 retval = ext2_xattr_get(inode, name_index, "", value, retval); 166 } 167 if (retval > 0) 168 acl = ext2_acl_from_disk(value, retval); 169 else if (retval == -ENODATA || retval == -ENOSYS) 170 acl = NULL; 171 else 172 acl = ERR_PTR(retval); 173 kfree(value); 174 175 return acl; 176 } 177 178 /* 179 * inode->i_mutex: down 180 */ 181 int 182 ext2_set_acl(struct inode *inode, struct posix_acl *acl, int type) 183 { 184 int name_index; 185 void *value = NULL; 186 size_t size = 0; 187 int error; 188 189 switch(type) { 190 case ACL_TYPE_ACCESS: 191 name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS; 192 if (acl) { 193 error = posix_acl_equiv_mode(acl, &inode->i_mode); 194 if (error < 0) 195 return error; 196 else { 197 inode->i_ctime = CURRENT_TIME_SEC; 198 mark_inode_dirty(inode); 199 if (error == 0) 200 acl = NULL; 201 } 202 } 203 break; 204 205 case ACL_TYPE_DEFAULT: 206 name_index = EXT2_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 = ext2_acl_to_disk(acl, &size); 216 if (IS_ERR(value)) 217 return (int)PTR_ERR(value); 218 } 219 220 error = ext2_xattr_set(inode, name_index, "", value, size, 0); 221 222 kfree(value); 223 if (!error) 224 set_cached_acl(inode, type, acl); 225 return error; 226 } 227 228 /* 229 * Initialize the ACLs of a new inode. Called from ext2_new_inode. 230 * 231 * dir->i_mutex: down 232 * inode->i_mutex: up (access to inode is still exclusive) 233 */ 234 int 235 ext2_init_acl(struct inode *inode, struct inode *dir) 236 { 237 struct posix_acl *default_acl, *acl; 238 int error; 239 240 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); 241 if (error) 242 return error; 243 244 if (default_acl) { 245 error = ext2_set_acl(inode, default_acl, ACL_TYPE_DEFAULT); 246 posix_acl_release(default_acl); 247 } 248 if (acl) { 249 if (!error) 250 error = ext2_set_acl(inode, acl, ACL_TYPE_ACCESS); 251 posix_acl_release(acl); 252 } 253 return error; 254 } 255