diff options
Diffstat (limited to 'fs/ntfs3/attrlist.c')
| -rw-r--r-- | fs/ntfs3/attrlist.c | 473 |
1 files changed, 473 insertions, 0 deletions
diff --git a/fs/ntfs3/attrlist.c b/fs/ntfs3/attrlist.c new file mode 100644 index 000000000..0c6a68e71 --- /dev/null +++ b/fs/ntfs3/attrlist.c @@ -0,0 +1,473 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * + * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved. + * + */ + +#include <linux/fs.h> + +#include "debug.h" +#include "ntfs.h" +#include "ntfs_fs.h" + +/* + * al_is_valid_le + * + * Return: True if @le is valid. + */ +static inline bool al_is_valid_le(const struct ntfs_inode *ni, + struct ATTR_LIST_ENTRY *le) +{ + if (!le || !ni->attr_list.le || !ni->attr_list.size) + return false; + + return PtrOffset(ni->attr_list.le, le) + le16_to_cpu(le->size) <= + ni->attr_list.size; +} + +void al_destroy(struct ntfs_inode *ni) +{ + run_close(&ni->attr_list.run); + kfree(ni->attr_list.le); + ni->attr_list.le = NULL; + ni->attr_list.size = 0; + ni->attr_list.dirty = false; +} + +/* + * ntfs_load_attr_list + * + * This method makes sure that the ATTRIB list, if present, + * has been properly set up. + */ +int ntfs_load_attr_list(struct ntfs_inode *ni, struct ATTRIB *attr) +{ + int err; + size_t lsize; + void *le = NULL; + + if (ni->attr_list.size) + return 0; + + if (!attr->non_res) { + lsize = le32_to_cpu(attr->res.data_size); + /* attr is resident: lsize < record_size (1K or 4K) */ + le = kvmalloc(al_aligned(lsize), GFP_KERNEL); + if (!le) { + err = -ENOMEM; + goto out; + } + memcpy(le, resident_data(attr), lsize); + } else if (attr->nres.svcn) { + err = -EINVAL; + goto out; + } else { + u16 run_off = le16_to_cpu(attr->nres.run_off); + + lsize = le64_to_cpu(attr->nres.data_size); + + run_init(&ni->attr_list.run); + + if (run_off > le32_to_cpu(attr->size)) { + err = -EINVAL; + goto out; + } + + err = run_unpack_ex(&ni->attr_list.run, ni->mi.sbi, ni->mi.rno, + 0, le64_to_cpu(attr->nres.evcn), 0, + Add2Ptr(attr, run_off), + le32_to_cpu(attr->size) - run_off); + if (err < 0) + goto out; + + /* attr is nonresident. + * The worst case: + * 1T (2^40) extremely fragmented file. + * cluster = 4K (2^12) => 2^28 fragments + * 2^9 fragments per one record => 2^19 records + * 2^5 bytes of ATTR_LIST_ENTRY per one record => 2^24 bytes. + * + * the result is 16M bytes per attribute list. + * Use kvmalloc to allocate in range [several Kbytes - dozen Mbytes] + */ + le = kvmalloc(al_aligned(lsize), GFP_KERNEL); + if (!le) { + err = -ENOMEM; + goto out; + } + + err = ntfs_read_run_nb(ni->mi.sbi, &ni->attr_list.run, 0, le, + lsize, NULL); + if (err) + goto out; + } + + ni->attr_list.size = lsize; + ni->attr_list.le = le; + + return 0; + +out: + ni->attr_list.le = le; + al_destroy(ni); + + return err; +} + +/* + * al_enumerate + * + * Return: + * * The next list le. + * * If @le is NULL then return the first le. + */ +struct ATTR_LIST_ENTRY *al_enumerate(struct ntfs_inode *ni, + struct ATTR_LIST_ENTRY *le) +{ + size_t off; + u16 sz; + + if (!le) { + le = ni->attr_list.le; + } else { + sz = le16_to_cpu(le->size); + if (sz < sizeof(struct ATTR_LIST_ENTRY)) { + /* Impossible 'cause we should not return such le. */ + return NULL; + } + le = Add2Ptr(le, sz); + } + + /* Check boundary. */ + off = PtrOffset(ni->attr_list.le, le); + if (off + sizeof(struct ATTR_LIST_ENTRY) > ni->attr_list.size) { + /* The regular end of list. */ + return NULL; + } + + sz = le16_to_cpu(le->size); + + /* Check le for errors. */ + if (sz < sizeof(struct ATTR_LIST_ENTRY) || + off + sz > ni->attr_list.size || + sz < le->name_off + le->name_len * sizeof(short)) { + return NULL; + } + + return le; +} + +/* + * al_find_le + * + * Find the first le in the list which matches type, name and VCN. + * + * Return: NULL if not found. + */ +struct ATTR_LIST_ENTRY *al_find_le(struct ntfs_inode *ni, + struct ATTR_LIST_ENTRY *le, + const struct ATTRIB *attr) +{ + CLST svcn = attr_svcn(attr); + + return al_find_ex(ni, le, attr->type, attr_name(attr), attr->name_len, + &svcn); +} + +/* + * al_find_ex + * + * Find the first le in the list which matches type, name and VCN. + * + * Return: NULL if not found. + */ +struct ATTR_LIST_ENTRY *al_find_ex(struct ntfs_inode *ni, + struct ATTR_LIST_ENTRY *le, + enum ATTR_TYPE type, const __le16 *name, + u8 name_len, const CLST *vcn) +{ + struct ATTR_LIST_ENTRY *ret = NULL; + u32 type_in = le32_to_cpu(type); + + while ((le = al_enumerate(ni, le))) { + u64 le_vcn; + int diff = le32_to_cpu(le->type) - type_in; + + /* List entries are sorted by type, name and VCN. */ + if (diff < 0) + continue; + + if (diff > 0) + return ret; + + if (le->name_len != name_len) + continue; + + le_vcn = le64_to_cpu(le->vcn); + if (!le_vcn) { + /* + * Compare entry names only for entry with vcn == 0. + */ + diff = ntfs_cmp_names(le_name(le), name_len, name, + name_len, ni->mi.sbi->upcase, + true); + if (diff < 0) + continue; + + if (diff > 0) + return ret; + } + + if (!vcn) + return le; + + if (*vcn == le_vcn) + return le; + + if (*vcn < le_vcn) + return ret; + + ret = le; + } + + return ret; +} + +/* + * al_find_le_to_insert + * + * Find the first list entry which matches type, name and VCN. + */ +static struct ATTR_LIST_ENTRY *al_find_le_to_insert(struct ntfs_inode *ni, + enum ATTR_TYPE type, + const __le16 *name, + u8 name_len, CLST vcn) +{ + struct ATTR_LIST_ENTRY *le = NULL, *prev; + u32 type_in = le32_to_cpu(type); + + /* List entries are sorted by type, name and VCN. */ + while ((le = al_enumerate(ni, prev = le))) { + int diff = le32_to_cpu(le->type) - type_in; + + if (diff < 0) + continue; + + if (diff > 0) + return le; + + if (!le->vcn) { + /* + * Compare entry names only for entry with vcn == 0. + */ + diff = ntfs_cmp_names(le_name(le), le->name_len, name, + name_len, ni->mi.sbi->upcase, + true); + if (diff < 0) + continue; + + if (diff > 0) + return le; + } + + if (le64_to_cpu(le->vcn) >= vcn) + return le; + } + + return prev ? Add2Ptr(prev, le16_to_cpu(prev->size)) : ni->attr_list.le; +} + +/* + * al_add_le + * + * Add an "attribute list entry" to the list. + */ +int al_add_le(struct ntfs_inode *ni, enum ATTR_TYPE type, const __le16 *name, + u8 name_len, CLST svcn, __le16 id, const struct MFT_REF *ref, + struct ATTR_LIST_ENTRY **new_le) +{ + int err; + struct ATTRIB *attr; + struct ATTR_LIST_ENTRY *le; + size_t off; + u16 sz; + size_t asize, new_asize, old_size; + u64 new_size; + typeof(ni->attr_list) *al = &ni->attr_list; + + /* + * Compute the size of the new 'le' + */ + sz = le_size(name_len); + old_size = al->size; + new_size = old_size + sz; + asize = al_aligned(old_size); + new_asize = al_aligned(new_size); + + /* Scan forward to the point at which the new 'le' should be inserted. */ + le = al_find_le_to_insert(ni, type, name, name_len, svcn); + off = PtrOffset(al->le, le); + + if (new_size > asize) { + void *ptr = kmalloc(new_asize, GFP_NOFS); + + if (!ptr) + return -ENOMEM; + + memcpy(ptr, al->le, off); + memcpy(Add2Ptr(ptr, off + sz), le, old_size - off); + le = Add2Ptr(ptr, off); + kfree(al->le); + al->le = ptr; + } else { + memmove(Add2Ptr(le, sz), le, old_size - off); + } + *new_le = le; + + al->size = new_size; + + le->type = type; + le->size = cpu_to_le16(sz); + le->name_len = name_len; + le->name_off = offsetof(struct ATTR_LIST_ENTRY, name); + le->vcn = cpu_to_le64(svcn); + le->ref = *ref; + le->id = id; + memcpy(le->name, name, sizeof(short) * name_len); + + err = attr_set_size(ni, ATTR_LIST, NULL, 0, &al->run, new_size, + &new_size, true, &attr); + if (err) { + /* Undo memmove above. */ + memmove(le, Add2Ptr(le, sz), old_size - off); + al->size = old_size; + return err; + } + + al->dirty = true; + + if (attr && attr->non_res) { + err = ntfs_sb_write_run(ni->mi.sbi, &al->run, 0, al->le, + al->size, 0); + if (err) + return err; + al->dirty = false; + } + + return 0; +} + +/* + * al_remove_le - Remove @le from attribute list. + */ +bool al_remove_le(struct ntfs_inode *ni, struct ATTR_LIST_ENTRY *le) +{ + u16 size; + size_t off; + typeof(ni->attr_list) *al = &ni->attr_list; + + if (!al_is_valid_le(ni, le)) + return false; + + /* Save on stack the size of 'le' */ + size = le16_to_cpu(le->size); + off = PtrOffset(al->le, le); + + memmove(le, Add2Ptr(le, size), al->size - (off + size)); + + al->size -= size; + al->dirty = true; + + return true; +} + +/* + * al_delete_le - Delete first le from the list which matches its parameters. + */ +bool al_delete_le(struct ntfs_inode *ni, enum ATTR_TYPE type, CLST vcn, + const __le16 *name, size_t name_len, + const struct MFT_REF *ref) +{ + u16 size; + struct ATTR_LIST_ENTRY *le; + size_t off; + typeof(ni->attr_list) *al = &ni->attr_list; + + /* Scan forward to the first le that matches the input. */ + le = al_find_ex(ni, NULL, type, name, name_len, &vcn); + if (!le) + return false; + + off = PtrOffset(al->le, le); + +next: + if (off >= al->size) + return false; + if (le->type != type) + return false; + if (le->name_len != name_len) + return false; + if (name_len && ntfs_cmp_names(le_name(le), name_len, name, name_len, + ni->mi.sbi->upcase, true)) + return false; + if (le64_to_cpu(le->vcn) != vcn) + return false; + + /* + * The caller specified a segment reference, so we have to + * scan through the matching entries until we find that segment + * reference or we run of matching entries. + */ + if (ref && memcmp(ref, &le->ref, sizeof(*ref))) { + off += le16_to_cpu(le->size); + le = Add2Ptr(al->le, off); + goto next; + } + + /* Save on stack the size of 'le'. */ + size = le16_to_cpu(le->size); + /* Delete the le. */ + memmove(le, Add2Ptr(le, size), al->size - (off + size)); + + al->size -= size; + al->dirty = true; + + return true; +} + +int al_update(struct ntfs_inode *ni, int sync) +{ + int err; + struct ATTRIB *attr; + typeof(ni->attr_list) *al = &ni->attr_list; + + if (!al->dirty || !al->size) + return 0; + + /* + * Attribute list increased on demand in al_add_le. + * Attribute list decreased here. + */ + err = attr_set_size(ni, ATTR_LIST, NULL, 0, &al->run, al->size, NULL, + false, &attr); + if (err) + goto out; + + if (!attr->non_res) { + memcpy(resident_data(attr), al->le, al->size); + } else { + err = ntfs_sb_write_run(ni->mi.sbi, &al->run, 0, al->le, + al->size, sync); + if (err) + goto out; + + attr->nres.valid_size = attr->nres.data_size; + } + + ni->mi.dirty = true; + al->dirty = false; + +out: + return err; +} |