fs/ntfs3/attrlist.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *
   4  * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
   5  *
   6  */
   7
   8 #include <linux/fs.h>
   9
  10 #include "debug.h"
  11 #include "ntfs.h"
  12 #include "ntfs_fs.h"
  13
  14 /*
  15  * al_is_valid_le
  16  *
  17  * Return: True if @le is valid.
  18  */
  19 static inline bool al_is_valid_le(const struct ntfs_inode *ni,
  20                                   struct ATTR_LIST_ENTRY *le)
  21 {
  22         if (!le || !ni->attr_list.le || !ni->attr_list.size)
  23                 return false;
  24
  25         return PtrOffset(ni->attr_list.le, le) + le16_to_cpu(le->size) <=
  26                ni->attr_list.size;
  27 }
  28
  29 void al_destroy(struct ntfs_inode *ni)
  30 {
  31         run_close(&ni->attr_list.run);
  32         kvfree(ni->attr_list.le);
  33         ni->attr_list.le = NULL;
  34         ni->attr_list.size = 0;
  35         ni->attr_list.dirty = false;
  36 }
  37
  38 /*
  39  * ntfs_load_attr_list
  40  *
  41  * This method makes sure that the ATTRIB list, if present,
  42  * has been properly set up.
  43  */
  44 int ntfs_load_attr_list(struct ntfs_inode *ni, struct ATTRIB *attr)
  45 {
  46         int err;
  47         size_t lsize;
  48         void *le = NULL;
  49
  50         if (ni->attr_list.size)
  51                 return 0;
  52
  53         if (!attr->non_res) {
  54                 lsize = le32_to_cpu(attr->res.data_size);
  55                 /* attr is resident: lsize < record_size (1K or 4K) */
  56                 le = kvmalloc(al_aligned(lsize), GFP_KERNEL);
  57                 if (!le) {
  58                         err = -ENOMEM;
  59                         goto out;
  60                 }
  61                 memcpy(le, resident_data(attr), lsize);
  62         } else if (attr->nres.svcn) {
  63                 err = -EINVAL;
  64                 goto out;
  65         } else {
  66                 u16 run_off = le16_to_cpu(attr->nres.run_off);
  67
  68                 lsize = le64_to_cpu(attr->nres.data_size);
  69
  70                 run_init(&ni->attr_list.run);
  71
  72                 if (run_off > le32_to_cpu(attr->size)) {
  73                         err = -EINVAL;
  74                         goto out;
  75                 }
  76
  77                 err = run_unpack_ex(&ni->attr_list.run, ni->mi.sbi, ni->mi.rno,
  78                                     0, le64_to_cpu(attr->nres.evcn), 0,
  79                                     Add2Ptr(attr, run_off),
  80                                     le32_to_cpu(attr->size) - run_off);
  81                 if (err < 0)
  82                         goto out;
  83
  84                 /* attr is nonresident.
  85                  * The worst case:
  86                  * 1T (2^40) extremely fragmented file.
  87                  * cluster = 4K (2^12) => 2^28 fragments
  88                  * 2^9 fragments per one record => 2^19 records
  89                  * 2^5 bytes of ATTR_LIST_ENTRY per one record => 2^24 bytes.
  90                  *
  91                  * the result is 16M bytes per attribute list.
  92                  * Use kvmalloc to allocate in range [several Kbytes - dozen Mbytes]
  93                  */
  94                 le = kvmalloc(al_aligned(lsize), GFP_KERNEL);
  95                 if (!le) {
  96                         err = -ENOMEM;
  97                         goto out;
  98                 }
  99
 100                 err = ntfs_read_run_nb(ni->mi.sbi, &ni->attr_list.run, 0, le,
 101                                        lsize, NULL);
 102                 if (err)
 103                         goto out;
 104         }
 105
 106         ni->attr_list.size = lsize;
 107         ni->attr_list.le = le;
 108
 109         return 0;
 110
 111 out:
 112         ni->attr_list.le = le;
 113         al_destroy(ni);
 114
 115         return err;
 116 }
 117
 118 /*
 119  * al_enumerate
 120  *
 121  * Return:
 122  * * The next list le.
 123  * * If @le is NULL then return the first le.
 124  */
 125 struct ATTR_LIST_ENTRY *al_enumerate(struct ntfs_inode *ni,
 126                                      struct ATTR_LIST_ENTRY *le)
 127 {
 128         size_t off;
 129         u16 sz;
 130         const unsigned le_min_size = le_size(0);
 131
 132         if (!le) {
 133                 le = ni->attr_list.le;
 134         } else {
 135                 sz = le16_to_cpu(le->size);
 136                 if (sz < le_min_size) {
 137                         /* Impossible 'cause we should not return such le. */
 138                         return NULL;
 139                 }
 140                 le = Add2Ptr(le, sz);
 141         }
 142
 143         /* Check boundary. */
 144         off = PtrOffset(ni->attr_list.le, le);
 145         if (off + le_min_size > ni->attr_list.size) {
 146                 /* The regular end of list. */
 147                 return NULL;
 148         }
 149
 150         sz = le16_to_cpu(le->size);
 151
 152         /* Check le for errors. */
 153         if (sz < le_min_size || off + sz > ni->attr_list.size ||
 154             sz < le->name_off + le->name_len * sizeof(short)) {
 155                 return NULL;
 156         }
 157
 158         return le;
 159 }
 160
 161 /*
 162  * al_find_le
 163  *
 164  * Find the first le in the list which matches type, name and VCN.
 165  *
 166  * Return: NULL if not found.
 167  */
 168 struct ATTR_LIST_ENTRY *al_find_le(struct ntfs_inode *ni,
 169                                    struct ATTR_LIST_ENTRY *le,
 170                                    const struct ATTRIB *attr)
 171 {
 172         CLST svcn = attr_svcn(attr);
 173
 174         return al_find_ex(ni, le, attr->type, attr_name(attr), attr->name_len,
 175                           &svcn);
 176 }
 177
 178 /*
 179  * al_find_ex
 180  *
 181  * Find the first le in the list which matches type, name and VCN.
 182  *
 183  * Return: NULL if not found.
 184  */
 185 struct ATTR_LIST_ENTRY *al_find_ex(struct ntfs_inode *ni,
 186                                    struct ATTR_LIST_ENTRY *le,
 187                                    enum ATTR_TYPE type, const __le16 *name,
 188                                    u8 name_len, const CLST *vcn)
 189 {
 190         struct ATTR_LIST_ENTRY *ret = NULL;
 191         u32 type_in = le32_to_cpu(type);
 192
 193         while ((le = al_enumerate(ni, le))) {
 194                 u64 le_vcn;
 195                 int diff = le32_to_cpu(le->type) - type_in;
 196
 197                 /* List entries are sorted by type, name and VCN. */
 198                 if (diff < 0)
 199                         continue;
 200
 201                 if (diff > 0)
 202                         return ret;
 203
 204                 if (le->name_len != name_len)
 205                         continue;
 206
 207                 le_vcn = le64_to_cpu(le->vcn);
 208                 if (!le_vcn) {
 209                         /*
 210                          * Compare entry names only for entry with vcn == 0.
 211                          */
 212                         diff = ntfs_cmp_names(le_name(le), name_len, name,
 213                                               name_len, ni->mi.sbi->upcase,
 214                                               true);
 215                         if (diff < 0)
 216                                 continue;
 217
 218                         if (diff > 0)
 219                                 return ret;
 220                 }
 221
 222                 if (!vcn)
 223                         return le;
 224
 225                 if (*vcn == le_vcn)
 226                         return le;
 227
 228                 if (*vcn < le_vcn)
 229                         return ret;
 230
 231                 ret = le;
 232         }
 233
 234         return ret;
 235 }
 236
 237 /*
 238  * al_find_le_to_insert
 239  *
 240  * Find the first list entry which matches type, name and VCN.
 241  */
 242 static struct ATTR_LIST_ENTRY *al_find_le_to_insert(struct ntfs_inode *ni,
 243                                                     enum ATTR_TYPE type,
 244                                                     const __le16 *name,
 245                                                     u8 name_len, CLST vcn)
 246 {
 247         struct ATTR_LIST_ENTRY *le = NULL, *prev;
 248         u32 type_in = le32_to_cpu(type);
 249
 250         /* List entries are sorted by type, name and VCN. */
 251         while ((le = al_enumerate(ni, prev = le))) {
 252                 int diff = le32_to_cpu(le->type) - type_in;
 253
 254                 if (diff < 0)
 255                         continue;
 256
 257                 if (diff > 0)
 258                         return le;
 259
 260                 if (!le->vcn) {
 261                         /*
 262                          * Compare entry names only for entry with vcn == 0.
 263                          */
 264                         diff = ntfs_cmp_names(le_name(le), le->name_len, name,
 265                                               name_len, ni->mi.sbi->upcase,
 266                                               true);
 267                         if (diff < 0)
 268                                 continue;
 269
 270                         if (diff > 0)
 271                                 return le;
 272                 }
 273
 274                 if (le64_to_cpu(le->vcn) >= vcn)
 275                         return le;
 276         }
 277
 278         return prev ? Add2Ptr(prev, le16_to_cpu(prev->size)) : ni->attr_list.le;
 279 }
 280
 281 /*
 282  * al_add_le
 283  *
 284  * Add an "attribute list entry" to the list.
 285  */
 286 int al_add_le(struct ntfs_inode *ni, enum ATTR_TYPE type, const __le16 *name,
 287               u8 name_len, CLST svcn, __le16 id, const struct MFT_REF *ref,
 288               struct ATTR_LIST_ENTRY **new_le)
 289 {
 290         int err;
 291         struct ATTRIB *attr;
 292         struct ATTR_LIST_ENTRY *le;
 293         size_t off;
 294         u16 sz;
 295         size_t asize, new_asize, old_size;
 296         u64 new_size;
 297         typeof(ni->attr_list) *al = &ni->attr_list;
 298
 299         /*
 300          * Compute the size of the new 'le'
 301          */
 302         sz = le_size(name_len);
 303         old_size = al->size;
 304         new_size = old_size + sz;
 305         asize = al_aligned(old_size);
 306         new_asize = al_aligned(new_size);
 307
 308         /* Scan forward to the point at which the new 'le' should be inserted. */
 309         le = al_find_le_to_insert(ni, type, name, name_len, svcn);
 310         off = PtrOffset(al->le, le);
 311
 312         if (new_size > asize) {
 313                 void *ptr = kmalloc(new_asize, GFP_NOFS);
 314
 315                 if (!ptr)
 316                         return -ENOMEM;
 317
 318                 memcpy(ptr, al->le, off);
 319                 memcpy(Add2Ptr(ptr, off + sz), le, old_size - off);
 320                 le = Add2Ptr(ptr, off);
 321                 kvfree(al->le);
 322                 al->le = ptr;
 323         } else {
 324                 memmove(Add2Ptr(le, sz), le, old_size - off);
 325         }
 326         *new_le = le;
 327
 328         al->size = new_size;
 329
 330         le->type = type;
 331         le->size = cpu_to_le16(sz);
 332         le->name_len = name_len;
 333         le->name_off = offsetof(struct ATTR_LIST_ENTRY, name);
 334         le->vcn = cpu_to_le64(svcn);
 335         le->ref = *ref;
 336         le->id = id;
 337         memcpy(le->name, name, sizeof(short) * name_len);
 338
 339         err = attr_set_size(ni, ATTR_LIST, NULL, 0, &al->run, new_size,
 340                             &new_size, true, &attr);
 341         if (err) {
 342                 /* Undo memmove above. */
 343                 memmove(le, Add2Ptr(le, sz), old_size - off);
 344                 al->size = old_size;
 345                 return err;
 346         }
 347
 348         al->dirty = true;
 349
 350         if (attr && attr->non_res) {
 351                 err = ntfs_sb_write_run(ni->mi.sbi, &al->run, 0, al->le,
 352                                         al->size, 0);
 353                 if (err)
 354                         return err;
 355                 al->dirty = false;
 356         }
 357
 358         return 0;
 359 }
 360
 361 /*
 362  * al_remove_le - Remove @le from attribute list.
 363  */
 364 bool al_remove_le(struct ntfs_inode *ni, struct ATTR_LIST_ENTRY *le)
 365 {
 366         u16 size;
 367         size_t off;
 368         typeof(ni->attr_list) *al = &ni->attr_list;
 369
 370         if (!al_is_valid_le(ni, le))
 371                 return false;
 372
 373         /* Save on stack the size of 'le' */
 374         size = le16_to_cpu(le->size);
 375         off = PtrOffset(al->le, le);
 376
 377         memmove(le, Add2Ptr(le, size), al->size - (off + size));
 378
 379         al->size -= size;
 380         al->dirty = true;
 381
 382         return true;
 383 }
 384
 385 int al_update(struct ntfs_inode *ni, int sync)
 386 {
 387         int err;
 388         struct ATTRIB *attr;
 389         typeof(ni->attr_list) *al = &ni->attr_list;
 390
 391         if (!al->dirty || !al->size)
 392                 return 0;
 393
 394         /*
 395          * Attribute list increased on demand in al_add_le.
 396          * Attribute list decreased here.
 397          */
 398         err = attr_set_size(ni, ATTR_LIST, NULL, 0, &al->run, al->size, NULL,
 399                             false, &attr);
 400         if (err)
 401                 goto out;
 402
 403         if (!attr->non_res) {
 404                 memcpy(resident_data(attr), al->le, al->size);
 405         } else {
 406                 err = ntfs_sb_write_run(ni->mi.sbi, &al->run, 0, al->le,
 407                                         al->size, sync);
 408                 if (err)
 409                         goto out;
 410
 411                 attr->nres.valid_size = attr->nres.data_size;
 412         }
 413
 414         ni->mi.dirty = true;
 415         al->dirty = false;
 416
 417 out:
 418         return err;
 419 }