1 /* 2 * JFFS2 -- Journalling Flash File System, Version 2. 3 * 4 * Copyright © 2006 NEC Corporation 5 * 6 * Created by KaiGai Kohei <kaigai@ak.jp.nec.com> 7 * 8 * For licensing information, see the file 'LICENCE' in this directory. 9 * 10 */ 11 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 14 #include <linux/kernel.h> 15 #include <linux/slab.h> 16 #include <linux/fs.h> 17 #include <linux/sched.h> 18 #include <linux/time.h> 19 #include <linux/crc32.h> 20 #include <linux/jffs2.h> 21 #include <linux/xattr.h> 22 #include <linux/posix_acl_xattr.h> 23 #include <linux/mtd/mtd.h> 24 #include "nodelist.h" 25 26 static size_t jffs2_acl_size(int count) 27 { 28 if (count <= 4) { 29 return sizeof(struct jffs2_acl_header) 30 + count * sizeof(struct jffs2_acl_entry_short); 31 } else { 32 return sizeof(struct jffs2_acl_header) 33 + 4 * sizeof(struct jffs2_acl_entry_short) 34 + (count - 4) * sizeof(struct jffs2_acl_entry); 35 } 36 } 37 38 static int jffs2_acl_count(size_t size) 39 { 40 size_t s; 41 42 size -= sizeof(struct jffs2_acl_header); 43 if (size < 4 * sizeof(struct jffs2_acl_entry_short)) { 44 if (size % sizeof(struct jffs2_acl_entry_short)) 45 return -1; 46 return size / sizeof(struct jffs2_acl_entry_short); 47 } else { 48 s = size - 4 * sizeof(struct jffs2_acl_entry_short); 49 if (s % sizeof(struct jffs2_acl_entry)) 50 return -1; 51 return s / sizeof(struct jffs2_acl_entry) + 4; 52 } 53 } 54 55 static struct posix_acl *jffs2_acl_from_medium(void *value, size_t size) 56 { 57 void *end = value + size; 58 struct jffs2_acl_header *header = value; 59 struct jffs2_acl_entry *entry; 60 struct posix_acl *acl; 61 uint32_t ver; 62 int i, count; 63 64 if (!value) 65 return NULL; 66 if (size < sizeof(struct jffs2_acl_header)) 67 return ERR_PTR(-EINVAL); 68 ver = je32_to_cpu(header->a_version); 69 if (ver != JFFS2_ACL_VERSION) { 70 JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver); 71 return ERR_PTR(-EINVAL); 72 } 73 74 value += sizeof(struct jffs2_acl_header); 75 count = jffs2_acl_count(size); 76 if (count < 0) 77 return ERR_PTR(-EINVAL); 78 if (count == 0) 79 return NULL; 80 81 acl = posix_acl_alloc(count, GFP_KERNEL); 82 if (!acl) 83 return ERR_PTR(-ENOMEM); 84 85 for (i=0; i < count; i++) { 86 entry = value; 87 if (value + sizeof(struct jffs2_acl_entry_short) > end) 88 goto fail; 89 acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag); 90 acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm); 91 switch (acl->a_entries[i].e_tag) { 92 case ACL_USER_OBJ: 93 case ACL_GROUP_OBJ: 94 case ACL_MASK: 95 case ACL_OTHER: 96 value += sizeof(struct jffs2_acl_entry_short); 97 break; 98 99 case ACL_USER: 100 value += sizeof(struct jffs2_acl_entry); 101 if (value > end) 102 goto fail; 103 acl->a_entries[i].e_uid = 104 make_kuid(&init_user_ns, 105 je32_to_cpu(entry->e_id)); 106 break; 107 case ACL_GROUP: 108 value += sizeof(struct jffs2_acl_entry); 109 if (value > end) 110 goto fail; 111 acl->a_entries[i].e_gid = 112 make_kgid(&init_user_ns, 113 je32_to_cpu(entry->e_id)); 114 break; 115 116 default: 117 goto fail; 118 } 119 } 120 if (value != end) 121 goto fail; 122 return acl; 123 fail: 124 posix_acl_release(acl); 125 return ERR_PTR(-EINVAL); 126 } 127 128 static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size) 129 { 130 struct jffs2_acl_header *header; 131 struct jffs2_acl_entry *entry; 132 void *e; 133 size_t i; 134 135 *size = jffs2_acl_size(acl->a_count); 136 header = kmalloc(struct_size(header, a_entries, acl->a_count), 137 GFP_KERNEL); 138 if (!header) 139 return ERR_PTR(-ENOMEM); 140 header->a_version = cpu_to_je32(JFFS2_ACL_VERSION); 141 e = header + 1; 142 for (i=0; i < acl->a_count; i++) { 143 const struct posix_acl_entry *acl_e = &acl->a_entries[i]; 144 entry = e; 145 entry->e_tag = cpu_to_je16(acl_e->e_tag); 146 entry->e_perm = cpu_to_je16(acl_e->e_perm); 147 switch(acl_e->e_tag) { 148 case ACL_USER: 149 entry->e_id = cpu_to_je32( 150 from_kuid(&init_user_ns, acl_e->e_uid)); 151 e += sizeof(struct jffs2_acl_entry); 152 break; 153 case ACL_GROUP: 154 entry->e_id = cpu_to_je32( 155 from_kgid(&init_user_ns, acl_e->e_gid)); 156 e += sizeof(struct jffs2_acl_entry); 157 break; 158 159 case ACL_USER_OBJ: 160 case ACL_GROUP_OBJ: 161 case ACL_MASK: 162 case ACL_OTHER: 163 e += sizeof(struct jffs2_acl_entry_short); 164 break; 165 166 default: 167 goto fail; 168 } 169 } 170 return header; 171 fail: 172 kfree(header); 173 return ERR_PTR(-EINVAL); 174 } 175 176 struct posix_acl *jffs2_get_acl(struct inode *inode, int type, bool rcu) 177 { 178 struct posix_acl *acl; 179 char *value = NULL; 180 int rc, xprefix; 181 182 if (rcu) 183 return ERR_PTR(-ECHILD); 184 185 switch (type) { 186 case ACL_TYPE_ACCESS: 187 xprefix = JFFS2_XPREFIX_ACL_ACCESS; 188 break; 189 case ACL_TYPE_DEFAULT: 190 xprefix = JFFS2_XPREFIX_ACL_DEFAULT; 191 break; 192 default: 193 BUG(); 194 } 195 rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0); 196 if (rc > 0) { 197 value = kmalloc(rc, GFP_KERNEL); 198 if (!value) 199 return ERR_PTR(-ENOMEM); 200 rc = do_jffs2_getxattr(inode, xprefix, "", value, rc); 201 } 202 if (rc > 0) { 203 acl = jffs2_acl_from_medium(value, rc); 204 } else if (rc == -ENODATA || rc == -ENOSYS) { 205 acl = NULL; 206 } else { 207 acl = ERR_PTR(rc); 208 } 209 kfree(value); 210 return acl; 211 } 212 213 static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl) 214 { 215 char *value = NULL; 216 size_t size = 0; 217 int rc; 218 219 if (acl) { 220 value = jffs2_acl_to_medium(acl, &size); 221 if (IS_ERR(value)) 222 return PTR_ERR(value); 223 } 224 rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0); 225 if (!value && rc == -ENODATA) 226 rc = 0; 227 kfree(value); 228 229 return rc; 230 } 231 232 int jffs2_set_acl(struct user_namespace *mnt_userns, struct inode *inode, 233 struct posix_acl *acl, int type) 234 { 235 int rc, xprefix; 236 237 switch (type) { 238 case ACL_TYPE_ACCESS: 239 xprefix = JFFS2_XPREFIX_ACL_ACCESS; 240 if (acl) { 241 umode_t mode; 242 243 rc = posix_acl_update_mode(&init_user_ns, inode, &mode, 244 &acl); 245 if (rc) 246 return rc; 247 if (inode->i_mode != mode) { 248 struct iattr attr; 249 250 attr.ia_valid = ATTR_MODE | ATTR_CTIME; 251 attr.ia_mode = mode; 252 attr.ia_ctime = current_time(inode); 253 rc = jffs2_do_setattr(inode, &attr); 254 if (rc < 0) 255 return rc; 256 } 257 } 258 break; 259 case ACL_TYPE_DEFAULT: 260 xprefix = JFFS2_XPREFIX_ACL_DEFAULT; 261 if (!S_ISDIR(inode->i_mode)) 262 return acl ? -EACCES : 0; 263 break; 264 default: 265 return -EINVAL; 266 } 267 rc = __jffs2_set_acl(inode, xprefix, acl); 268 if (!rc) 269 set_cached_acl(inode, type, acl); 270 return rc; 271 } 272 273 int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, umode_t *i_mode) 274 { 275 struct posix_acl *default_acl, *acl; 276 int rc; 277 278 cache_no_acl(inode); 279 280 rc = posix_acl_create(dir_i, i_mode, &default_acl, &acl); 281 if (rc) 282 return rc; 283 284 if (default_acl) { 285 set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl); 286 posix_acl_release(default_acl); 287 } 288 if (acl) { 289 set_cached_acl(inode, ACL_TYPE_ACCESS, acl); 290 posix_acl_release(acl); 291 } 292 return 0; 293 } 294 295 int jffs2_init_acl_post(struct inode *inode) 296 { 297 int rc; 298 299 if (inode->i_default_acl) { 300 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl); 301 if (rc) 302 return rc; 303 } 304 305 if (inode->i_acl) { 306 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl); 307 if (rc) 308 return rc; 309 } 310 311 return 0; 312 } 313