1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/ext2/acl.c 4 * 5 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de> 6 */ 7 8 #include <linux/init.h> 9 #include <linux/sched.h> 10 #include <linux/slab.h> 11 #include <linux/fs.h> 12 #include "ext2.h" 13 #include "xattr.h" 14 #include "acl.h" 15 16 /* 17 * Convert from filesystem to in-memory representation. 18 */ 19 static struct posix_acl * 20 ext2_acl_from_disk(const void *value, size_t size) 21 { 22 const char *end = (char *)value + size; 23 int n, count; 24 struct posix_acl *acl; 25 26 if (!value) 27 return NULL; 28 if (size < sizeof(ext2_acl_header)) 29 return ERR_PTR(-EINVAL); 30 if (((ext2_acl_header *)value)->a_version != 31 cpu_to_le32(EXT2_ACL_VERSION)) 32 return ERR_PTR(-EINVAL); 33 value = (char *)value + sizeof(ext2_acl_header); 34 count = ext2_acl_count(size); 35 if (count < 0) 36 return ERR_PTR(-EINVAL); 37 if (count == 0) 38 return NULL; 39 acl = posix_acl_alloc(count, GFP_KERNEL); 40 if (!acl) 41 return ERR_PTR(-ENOMEM); 42 for (n=0; n < count; n++) { 43 ext2_acl_entry *entry = 44 (ext2_acl_entry *)value; 45 if ((char *)value + sizeof(ext2_acl_entry_short) > end) 46 goto fail; 47 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag); 48 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm); 49 switch(acl->a_entries[n].e_tag) { 50 case ACL_USER_OBJ: 51 case ACL_GROUP_OBJ: 52 case ACL_MASK: 53 case ACL_OTHER: 54 value = (char *)value + 55 sizeof(ext2_acl_entry_short); 56 break; 57 58 case ACL_USER: 59 value = (char *)value + sizeof(ext2_acl_entry); 60 if ((char *)value > end) 61 goto fail; 62 acl->a_entries[n].e_uid = 63 make_kuid(&init_user_ns, 64 le32_to_cpu(entry->e_id)); 65 break; 66 case ACL_GROUP: 67 value = (char *)value + sizeof(ext2_acl_entry); 68 if ((char *)value > end) 69 goto fail; 70 acl->a_entries[n].e_gid = 71 make_kgid(&init_user_ns, 72 le32_to_cpu(entry->e_id)); 73 break; 74 75 default: 76 goto fail; 77 } 78 } 79 if (value != end) 80 goto fail; 81 return acl; 82 83 fail: 84 posix_acl_release(acl); 85 return ERR_PTR(-EINVAL); 86 } 87 88 /* 89 * Convert from in-memory to filesystem representation. 90 */ 91 static void * 92 ext2_acl_to_disk(const struct posix_acl *acl, size_t *size) 93 { 94 ext2_acl_header *ext_acl; 95 char *e; 96 size_t n; 97 98 *size = ext2_acl_size(acl->a_count); 99 ext_acl = kmalloc(sizeof(ext2_acl_header) + acl->a_count * 100 sizeof(ext2_acl_entry), GFP_KERNEL); 101 if (!ext_acl) 102 return ERR_PTR(-ENOMEM); 103 ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION); 104 e = (char *)ext_acl + sizeof(ext2_acl_header); 105 for (n=0; n < acl->a_count; n++) { 106 const struct posix_acl_entry *acl_e = &acl->a_entries[n]; 107 ext2_acl_entry *entry = (ext2_acl_entry *)e; 108 entry->e_tag = cpu_to_le16(acl_e->e_tag); 109 entry->e_perm = cpu_to_le16(acl_e->e_perm); 110 switch(acl_e->e_tag) { 111 case ACL_USER: 112 entry->e_id = cpu_to_le32( 113 from_kuid(&init_user_ns, acl_e->e_uid)); 114 e += sizeof(ext2_acl_entry); 115 break; 116 case ACL_GROUP: 117 entry->e_id = cpu_to_le32( 118 from_kgid(&init_user_ns, acl_e->e_gid)); 119 e += sizeof(ext2_acl_entry); 120 break; 121 122 case ACL_USER_OBJ: 123 case ACL_GROUP_OBJ: 124 case ACL_MASK: 125 case ACL_OTHER: 126 e += sizeof(ext2_acl_entry_short); 127 break; 128 129 default: 130 goto fail; 131 } 132 } 133 return (char *)ext_acl; 134 135 fail: 136 kfree(ext_acl); 137 return ERR_PTR(-EINVAL); 138 } 139 140 /* 141 * inode->i_mutex: don't care 142 */ 143 struct posix_acl * 144 ext2_get_acl(struct inode *inode, int type, bool rcu) 145 { 146 int name_index; 147 char *value = NULL; 148 struct posix_acl *acl; 149 int retval; 150 151 if (rcu) 152 return ERR_PTR(-ECHILD); 153 154 switch (type) { 155 case ACL_TYPE_ACCESS: 156 name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS; 157 break; 158 case ACL_TYPE_DEFAULT: 159 name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT; 160 break; 161 default: 162 BUG(); 163 } 164 retval = ext2_xattr_get(inode, name_index, "", NULL, 0); 165 if (retval > 0) { 166 value = kmalloc(retval, GFP_KERNEL); 167 if (!value) 168 return ERR_PTR(-ENOMEM); 169 retval = ext2_xattr_get(inode, name_index, "", value, retval); 170 } 171 if (retval > 0) 172 acl = ext2_acl_from_disk(value, retval); 173 else if (retval == -ENODATA || retval == -ENOSYS) 174 acl = NULL; 175 else 176 acl = ERR_PTR(retval); 177 kfree(value); 178 179 return acl; 180 } 181 182 static int 183 __ext2_set_acl(struct inode *inode, struct posix_acl *acl, int type) 184 { 185 int name_index; 186 void *value = NULL; 187 size_t size = 0; 188 int error; 189 190 switch(type) { 191 case ACL_TYPE_ACCESS: 192 name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS; 193 break; 194 195 case ACL_TYPE_DEFAULT: 196 name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT; 197 if (!S_ISDIR(inode->i_mode)) 198 return acl ? -EACCES : 0; 199 break; 200 201 default: 202 return -EINVAL; 203 } 204 if (acl) { 205 value = ext2_acl_to_disk(acl, &size); 206 if (IS_ERR(value)) 207 return (int)PTR_ERR(value); 208 } 209 210 error = ext2_xattr_set(inode, name_index, "", value, size, 0); 211 212 kfree(value); 213 if (!error) 214 set_cached_acl(inode, type, acl); 215 return error; 216 } 217 218 /* 219 * inode->i_mutex: down 220 */ 221 int 222 ext2_set_acl(struct user_namespace *mnt_userns, struct inode *inode, 223 struct posix_acl *acl, int type) 224 { 225 int error; 226 int update_mode = 0; 227 umode_t mode = inode->i_mode; 228 229 if (type == ACL_TYPE_ACCESS && acl) { 230 error = posix_acl_update_mode(&init_user_ns, inode, &mode, 231 &acl); 232 if (error) 233 return error; 234 update_mode = 1; 235 } 236 error = __ext2_set_acl(inode, acl, type); 237 if (!error && update_mode) { 238 inode->i_mode = mode; 239 inode->i_ctime = current_time(inode); 240 mark_inode_dirty(inode); 241 } 242 return error; 243 } 244 245 /* 246 * Initialize the ACLs of a new inode. Called from ext2_new_inode. 247 * 248 * dir->i_mutex: down 249 * inode->i_mutex: up (access to inode is still exclusive) 250 */ 251 int 252 ext2_init_acl(struct inode *inode, struct inode *dir) 253 { 254 struct posix_acl *default_acl, *acl; 255 int error; 256 257 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); 258 if (error) 259 return error; 260 261 if (default_acl) { 262 error = __ext2_set_acl(inode, default_acl, ACL_TYPE_DEFAULT); 263 posix_acl_release(default_acl); 264 } else { 265 inode->i_default_acl = NULL; 266 } 267 if (acl) { 268 if (!error) 269 error = __ext2_set_acl(inode, acl, ACL_TYPE_ACCESS); 270 posix_acl_release(acl); 271 } else { 272 inode->i_acl = NULL; 273 } 274 return error; 275 } 276