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linux/fs/ntfs/index.c
Thomas Gleixner a1d312de77 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 96 
Based on 1 normalized pattern(s):

  this program include file is free software you can redistribute it
  and or modify it under the terms of the gnu general public license
  as published by the free software foundation either version 2 of the
  license or at your option any later version this program include
  file is distributed in the hope that it will be useful but without
  any warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program in the main directory of the
  linux [ntfs] distribution in the file copying if not write to the
  free software foundation inc 59 temple place suite 330 boston ma
  02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 43 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520075212.517001706@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:37:53 +02:00

441 lines
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* index.c - NTFS kernel index handling. Part of the Linux-NTFS project.
*
* Copyright (c) 2004-2005 Anton Altaparmakov
*/
#include <linux/slab.h>
#include "aops.h"
#include "collate.h"
#include "debug.h"
#include "index.h"
#include "ntfs.h"
/**
* ntfs_index_ctx_get - allocate and initialize a new index context
* @idx_ni: ntfs index inode with which to initialize the context
*
* Allocate a new index context, initialize it with @idx_ni and return it.
* Return NULL if allocation failed.
*
* Locking: Caller must hold i_mutex on the index inode.
*/
ntfs_index_context *ntfs_index_ctx_get(ntfs_inode *idx_ni)
{
ntfs_index_context *ictx;
ictx = kmem_cache_alloc(ntfs_index_ctx_cache, GFP_NOFS);
if (ictx)
*ictx = (ntfs_index_context){ .idx_ni = idx_ni };
return ictx;
}
/**
* ntfs_index_ctx_put - release an index context
* @ictx: index context to free
*
* Release the index context @ictx, releasing all associated resources.
*
* Locking: Caller must hold i_mutex on the index inode.
*/
void ntfs_index_ctx_put(ntfs_index_context *ictx)
{
if (ictx->entry) {
if (ictx->is_in_root) {
if (ictx->actx)
ntfs_attr_put_search_ctx(ictx->actx);
if (ictx->base_ni)
unmap_mft_record(ictx->base_ni);
} else {
struct page *page = ictx->page;
if (page) {
BUG_ON(!PageLocked(page));
unlock_page(page);
ntfs_unmap_page(page);
}
}
}
kmem_cache_free(ntfs_index_ctx_cache, ictx);
return;
}
/**
* ntfs_index_lookup - find a key in an index and return its index entry
* @key: [IN] key for which to search in the index
* @key_len: [IN] length of @key in bytes
* @ictx: [IN/OUT] context describing the index and the returned entry
*
* Before calling ntfs_index_lookup(), @ictx must have been obtained from a
* call to ntfs_index_ctx_get().
*
* Look for the @key in the index specified by the index lookup context @ictx.
* ntfs_index_lookup() walks the contents of the index looking for the @key.
*
* If the @key is found in the index, 0 is returned and @ictx is setup to
* describe the index entry containing the matching @key. @ictx->entry is the
* index entry and @ictx->data and @ictx->data_len are the index entry data and
* its length in bytes, respectively.
*
* If the @key is not found in the index, -ENOENT is returned and @ictx is
* setup to describe the index entry whose key collates immediately after the
* search @key, i.e. this is the position in the index at which an index entry
* with a key of @key would need to be inserted.
*
* If an error occurs return the negative error code and @ictx is left
* untouched.
*
* When finished with the entry and its data, call ntfs_index_ctx_put() to free
* the context and other associated resources.
*
* If the index entry was modified, call flush_dcache_index_entry_page()
* immediately after the modification and either ntfs_index_entry_mark_dirty()
* or ntfs_index_entry_write() before the call to ntfs_index_ctx_put() to
* ensure that the changes are written to disk.
*
* Locking: - Caller must hold i_mutex on the index inode.
* - Each page cache page in the index allocation mapping must be
* locked whilst being accessed otherwise we may find a corrupt
* page due to it being under ->writepage at the moment which
* applies the mst protection fixups before writing out and then
* removes them again after the write is complete after which it
* unlocks the page.
*/
int ntfs_index_lookup(const void *key, const int key_len,
ntfs_index_context *ictx)
{
VCN vcn, old_vcn;
ntfs_inode *idx_ni = ictx->idx_ni;
ntfs_volume *vol = idx_ni->vol;
struct super_block *sb = vol->sb;
ntfs_inode *base_ni = idx_ni->ext.base_ntfs_ino;
MFT_RECORD *m;
INDEX_ROOT *ir;
INDEX_ENTRY *ie;
INDEX_ALLOCATION *ia;
u8 *index_end, *kaddr;
ntfs_attr_search_ctx *actx;
struct address_space *ia_mapping;
struct page *page;
int rc, err = 0;
ntfs_debug("Entering.");
BUG_ON(!NInoAttr(idx_ni));
BUG_ON(idx_ni->type != AT_INDEX_ALLOCATION);
BUG_ON(idx_ni->nr_extents != -1);
BUG_ON(!base_ni);
BUG_ON(!key);
BUG_ON(key_len <= 0);
if (!ntfs_is_collation_rule_supported(
idx_ni->itype.index.collation_rule)) {
ntfs_error(sb, "Index uses unsupported collation rule 0x%x. "
"Aborting lookup.", le32_to_cpu(
idx_ni->itype.index.collation_rule));
return -EOPNOTSUPP;
}
/* Get hold of the mft record for the index inode. */
m = map_mft_record(base_ni);
if (IS_ERR(m)) {
ntfs_error(sb, "map_mft_record() failed with error code %ld.",
-PTR_ERR(m));
return PTR_ERR(m);
}
actx = ntfs_attr_get_search_ctx(base_ni, m);
if (unlikely(!actx)) {
err = -ENOMEM;
goto err_out;
}
/* Find the index root attribute in the mft record. */
err = ntfs_attr_lookup(AT_INDEX_ROOT, idx_ni->name, idx_ni->name_len,
CASE_SENSITIVE, 0, NULL, 0, actx);
if (unlikely(err)) {
if (err == -ENOENT) {
ntfs_error(sb, "Index root attribute missing in inode "
"0x%lx.", idx_ni->mft_no);
err = -EIO;
}
goto err_out;
}
/* Get to the index root value (it has been verified in read_inode). */
ir = (INDEX_ROOT*)((u8*)actx->attr +
le16_to_cpu(actx->attr->data.resident.value_offset));
index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
/* The first index entry. */
ie = (INDEX_ENTRY*)((u8*)&ir->index +
le32_to_cpu(ir->index.entries_offset));
/*
* Loop until we exceed valid memory (corruption case) or until we
* reach the last entry.
*/
for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
/* Bounds checks. */
if ((u8*)ie < (u8*)actx->mrec || (u8*)ie +
sizeof(INDEX_ENTRY_HEADER) > index_end ||
(u8*)ie + le16_to_cpu(ie->length) > index_end)
goto idx_err_out;
/*
* The last entry cannot contain a key. It can however contain
* a pointer to a child node in the B+tree so we just break out.
*/
if (ie->flags & INDEX_ENTRY_END)
break;
/* Further bounds checks. */
if ((u32)sizeof(INDEX_ENTRY_HEADER) +
le16_to_cpu(ie->key_length) >
le16_to_cpu(ie->data.vi.data_offset) ||
(u32)le16_to_cpu(ie->data.vi.data_offset) +
le16_to_cpu(ie->data.vi.data_length) >
le16_to_cpu(ie->length))
goto idx_err_out;
/* If the keys match perfectly, we setup @ictx and return 0. */
if ((key_len == le16_to_cpu(ie->key_length)) && !memcmp(key,
&ie->key, key_len)) {
ir_done:
ictx->is_in_root = true;
ictx->ir = ir;
ictx->actx = actx;
ictx->base_ni = base_ni;
ictx->ia = NULL;
ictx->page = NULL;
done:
ictx->entry = ie;
ictx->data = (u8*)ie +
le16_to_cpu(ie->data.vi.data_offset);
ictx->data_len = le16_to_cpu(ie->data.vi.data_length);
ntfs_debug("Done.");
return err;
}
/*
* Not a perfect match, need to do full blown collation so we
* know which way in the B+tree we have to go.
*/
rc = ntfs_collate(vol, idx_ni->itype.index.collation_rule, key,
key_len, &ie->key, le16_to_cpu(ie->key_length));
/*
* If @key collates before the key of the current entry, there
* is definitely no such key in this index but we might need to
* descend into the B+tree so we just break out of the loop.
*/
if (rc == -1)
break;
/*
* A match should never happen as the memcmp() call should have
* cought it, but we still treat it correctly.
*/
if (!rc)
goto ir_done;
/* The keys are not equal, continue the search. */
}
/*
* We have finished with this index without success. Check for the
* presence of a child node and if not present setup @ictx and return
* -ENOENT.
*/
if (!(ie->flags & INDEX_ENTRY_NODE)) {
ntfs_debug("Entry not found.");
err = -ENOENT;
goto ir_done;
} /* Child node present, descend into it. */
/* Consistency check: Verify that an index allocation exists. */
if (!NInoIndexAllocPresent(idx_ni)) {
ntfs_error(sb, "No index allocation attribute but index entry "
"requires one. Inode 0x%lx is corrupt or "
"driver bug.", idx_ni->mft_no);
goto err_out;
}
/* Get the starting vcn of the index_block holding the child node. */
vcn = sle64_to_cpup((sle64*)((u8*)ie + le16_to_cpu(ie->length) - 8));
ia_mapping = VFS_I(idx_ni)->i_mapping;
/*
* We are done with the index root and the mft record. Release them,
* otherwise we deadlock with ntfs_map_page().
*/
ntfs_attr_put_search_ctx(actx);
unmap_mft_record(base_ni);
m = NULL;
actx = NULL;
descend_into_child_node:
/*
* Convert vcn to index into the index allocation attribute in units
* of PAGE_SIZE and map the page cache page, reading it from
* disk if necessary.
*/
page = ntfs_map_page(ia_mapping, vcn <<
idx_ni->itype.index.vcn_size_bits >> PAGE_SHIFT);
if (IS_ERR(page)) {
ntfs_error(sb, "Failed to map index page, error %ld.",
-PTR_ERR(page));
err = PTR_ERR(page);
goto err_out;
}
lock_page(page);
kaddr = (u8*)page_address(page);
fast_descend_into_child_node:
/* Get to the index allocation block. */
ia = (INDEX_ALLOCATION*)(kaddr + ((vcn <<
idx_ni->itype.index.vcn_size_bits) & ~PAGE_MASK));
/* Bounds checks. */
if ((u8*)ia < kaddr || (u8*)ia > kaddr + PAGE_SIZE) {
ntfs_error(sb, "Out of bounds check failed. Corrupt inode "
"0x%lx or driver bug.", idx_ni->mft_no);
goto unm_err_out;
}
/* Catch multi sector transfer fixup errors. */
if (unlikely(!ntfs_is_indx_record(ia->magic))) {
ntfs_error(sb, "Index record with vcn 0x%llx is corrupt. "
"Corrupt inode 0x%lx. Run chkdsk.",
(long long)vcn, idx_ni->mft_no);
goto unm_err_out;
}
if (sle64_to_cpu(ia->index_block_vcn) != vcn) {
ntfs_error(sb, "Actual VCN (0x%llx) of index buffer is "
"different from expected VCN (0x%llx). Inode "
"0x%lx is corrupt or driver bug.",
(unsigned long long)
sle64_to_cpu(ia->index_block_vcn),
(unsigned long long)vcn, idx_ni->mft_no);
goto unm_err_out;
}
if (le32_to_cpu(ia->index.allocated_size) + 0x18 !=
idx_ni->itype.index.block_size) {
ntfs_error(sb, "Index buffer (VCN 0x%llx) of inode 0x%lx has "
"a size (%u) differing from the index "
"specified size (%u). Inode is corrupt or "
"driver bug.", (unsigned long long)vcn,
idx_ni->mft_no,
le32_to_cpu(ia->index.allocated_size) + 0x18,
idx_ni->itype.index.block_size);
goto unm_err_out;
}
index_end = (u8*)ia + idx_ni->itype.index.block_size;
if (index_end > kaddr + PAGE_SIZE) {
ntfs_error(sb, "Index buffer (VCN 0x%llx) of inode 0x%lx "
"crosses page boundary. Impossible! Cannot "
"access! This is probably a bug in the "
"driver.", (unsigned long long)vcn,
idx_ni->mft_no);
goto unm_err_out;
}
index_end = (u8*)&ia->index + le32_to_cpu(ia->index.index_length);
if (index_end > (u8*)ia + idx_ni->itype.index.block_size) {
ntfs_error(sb, "Size of index buffer (VCN 0x%llx) of inode "
"0x%lx exceeds maximum size.",
(unsigned long long)vcn, idx_ni->mft_no);
goto unm_err_out;
}
/* The first index entry. */
ie = (INDEX_ENTRY*)((u8*)&ia->index +
le32_to_cpu(ia->index.entries_offset));
/*
* Iterate similar to above big loop but applied to index buffer, thus
* loop until we exceed valid memory (corruption case) or until we
* reach the last entry.
*/
for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
/* Bounds checks. */
if ((u8*)ie < (u8*)ia || (u8*)ie +
sizeof(INDEX_ENTRY_HEADER) > index_end ||
(u8*)ie + le16_to_cpu(ie->length) > index_end) {
ntfs_error(sb, "Index entry out of bounds in inode "
"0x%lx.", idx_ni->mft_no);
goto unm_err_out;
}
/*
* The last entry cannot contain a key. It can however contain
* a pointer to a child node in the B+tree so we just break out.
*/
if (ie->flags & INDEX_ENTRY_END)
break;
/* Further bounds checks. */
if ((u32)sizeof(INDEX_ENTRY_HEADER) +
le16_to_cpu(ie->key_length) >
le16_to_cpu(ie->data.vi.data_offset) ||
(u32)le16_to_cpu(ie->data.vi.data_offset) +
le16_to_cpu(ie->data.vi.data_length) >
le16_to_cpu(ie->length)) {
ntfs_error(sb, "Index entry out of bounds in inode "
"0x%lx.", idx_ni->mft_no);
goto unm_err_out;
}
/* If the keys match perfectly, we setup @ictx and return 0. */
if ((key_len == le16_to_cpu(ie->key_length)) && !memcmp(key,
&ie->key, key_len)) {
ia_done:
ictx->is_in_root = false;
ictx->actx = NULL;
ictx->base_ni = NULL;
ictx->ia = ia;
ictx->page = page;
goto done;
}
/*
* Not a perfect match, need to do full blown collation so we
* know which way in the B+tree we have to go.
*/
rc = ntfs_collate(vol, idx_ni->itype.index.collation_rule, key,
key_len, &ie->key, le16_to_cpu(ie->key_length));
/*
* If @key collates before the key of the current entry, there
* is definitely no such key in this index but we might need to
* descend into the B+tree so we just break out of the loop.
*/
if (rc == -1)
break;
/*
* A match should never happen as the memcmp() call should have
* cought it, but we still treat it correctly.
*/
if (!rc)
goto ia_done;
/* The keys are not equal, continue the search. */
}
/*
* We have finished with this index buffer without success. Check for
* the presence of a child node and if not present return -ENOENT.
*/
if (!(ie->flags & INDEX_ENTRY_NODE)) {
ntfs_debug("Entry not found.");
err = -ENOENT;
goto ia_done;
}
if ((ia->index.flags & NODE_MASK) == LEAF_NODE) {
ntfs_error(sb, "Index entry with child node found in a leaf "
"node in inode 0x%lx.", idx_ni->mft_no);
goto unm_err_out;
}
/* Child node present, descend into it. */
old_vcn = vcn;
vcn = sle64_to_cpup((sle64*)((u8*)ie + le16_to_cpu(ie->length) - 8));
if (vcn >= 0) {
/*
* If vcn is in the same page cache page as old_vcn we recycle
* the mapped page.
*/
if (old_vcn << vol->cluster_size_bits >>
PAGE_SHIFT == vcn <<
vol->cluster_size_bits >>
PAGE_SHIFT)
goto fast_descend_into_child_node;
unlock_page(page);
ntfs_unmap_page(page);
goto descend_into_child_node;
}
ntfs_error(sb, "Negative child node vcn in inode 0x%lx.",
idx_ni->mft_no);
unm_err_out:
unlock_page(page);
ntfs_unmap_page(page);
err_out:
if (!err)
err = -EIO;
if (actx)
ntfs_attr_put_search_ctx(actx);
if (m)
unmap_mft_record(base_ni);
return err;
idx_err_out:
ntfs_error(sb, "Corrupt index. Aborting lookup.");
goto err_out;
}
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