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-rw-r--r--fs/ntfs/namei.c391
1 files changed, 391 insertions, 0 deletions
diff --git a/fs/ntfs/namei.c b/fs/ntfs/namei.c
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--- /dev/null
+++ b/fs/ntfs/namei.c
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+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * namei.c - NTFS kernel directory inode operations. Part of the Linux-NTFS
+ * project.
+ *
+ * Copyright (c) 2001-2006 Anton Altaparmakov
+ */
+
+#include <linux/dcache.h>
+#include <linux/exportfs.h>
+#include <linux/security.h>
+#include <linux/slab.h>
+
+#include "attrib.h"
+#include "debug.h"
+#include "dir.h"
+#include "mft.h"
+#include "ntfs.h"
+
+/**
+ * ntfs_lookup - find the inode represented by a dentry in a directory inode
+ * @dir_ino: directory inode in which to look for the inode
+ * @dent: dentry representing the inode to look for
+ * @flags: lookup flags
+ *
+ * In short, ntfs_lookup() looks for the inode represented by the dentry @dent
+ * in the directory inode @dir_ino and if found attaches the inode to the
+ * dentry @dent.
+ *
+ * In more detail, the dentry @dent specifies which inode to look for by
+ * supplying the name of the inode in @dent->d_name.name. ntfs_lookup()
+ * converts the name to Unicode and walks the contents of the directory inode
+ * @dir_ino looking for the converted Unicode name. If the name is found in the
+ * directory, the corresponding inode is loaded by calling ntfs_iget() on its
+ * inode number and the inode is associated with the dentry @dent via a call to
+ * d_splice_alias().
+ *
+ * If the name is not found in the directory, a NULL inode is inserted into the
+ * dentry @dent via a call to d_add(). The dentry is then termed a negative
+ * dentry.
+ *
+ * Only if an actual error occurs, do we return an error via ERR_PTR().
+ *
+ * In order to handle the case insensitivity issues of NTFS with regards to the
+ * dcache and the dcache requiring only one dentry per directory, we deal with
+ * dentry aliases that only differ in case in ->ntfs_lookup() while maintaining
+ * a case sensitive dcache. This means that we get the full benefit of dcache
+ * speed when the file/directory is looked up with the same case as returned by
+ * ->ntfs_readdir() but that a lookup for any other case (or for the short file
+ * name) will not find anything in dcache and will enter ->ntfs_lookup()
+ * instead, where we search the directory for a fully matching file name
+ * (including case) and if that is not found, we search for a file name that
+ * matches with different case and if that has non-POSIX semantics we return
+ * that. We actually do only one search (case sensitive) and keep tabs on
+ * whether we have found a case insensitive match in the process.
+ *
+ * To simplify matters for us, we do not treat the short vs long filenames as
+ * two hard links but instead if the lookup matches a short filename, we
+ * return the dentry for the corresponding long filename instead.
+ *
+ * There are three cases we need to distinguish here:
+ *
+ * 1) @dent perfectly matches (i.e. including case) a directory entry with a
+ * file name in the WIN32 or POSIX namespaces. In this case
+ * ntfs_lookup_inode_by_name() will return with name set to NULL and we
+ * just d_splice_alias() @dent.
+ * 2) @dent matches (not including case) a directory entry with a file name in
+ * the WIN32 namespace. In this case ntfs_lookup_inode_by_name() will return
+ * with name set to point to a kmalloc()ed ntfs_name structure containing
+ * the properly cased little endian Unicode name. We convert the name to the
+ * current NLS code page, search if a dentry with this name already exists
+ * and if so return that instead of @dent. At this point things are
+ * complicated by the possibility of 'disconnected' dentries due to NFS
+ * which we deal with appropriately (see the code comments). The VFS will
+ * then destroy the old @dent and use the one we returned. If a dentry is
+ * not found, we allocate a new one, d_splice_alias() it, and return it as
+ * above.
+ * 3) @dent matches either perfectly or not (i.e. we don't care about case) a
+ * directory entry with a file name in the DOS namespace. In this case
+ * ntfs_lookup_inode_by_name() will return with name set to point to a
+ * kmalloc()ed ntfs_name structure containing the mft reference (cpu endian)
+ * of the inode. We use the mft reference to read the inode and to find the
+ * file name in the WIN32 namespace corresponding to the matched short file
+ * name. We then convert the name to the current NLS code page, and proceed
+ * searching for a dentry with this name, etc, as in case 2), above.
+ *
+ * Locking: Caller must hold i_mutex on the directory.
+ */
+static struct dentry *ntfs_lookup(struct inode *dir_ino, struct dentry *dent,
+ unsigned int flags)
+{
+ ntfs_volume *vol = NTFS_SB(dir_ino->i_sb);
+ struct inode *dent_inode;
+ ntfschar *uname;
+ ntfs_name *name = NULL;
+ MFT_REF mref;
+ unsigned long dent_ino;
+ int uname_len;
+
+ ntfs_debug("Looking up %pd in directory inode 0x%lx.",
+ dent, dir_ino->i_ino);
+ /* Convert the name of the dentry to Unicode. */
+ uname_len = ntfs_nlstoucs(vol, dent->d_name.name, dent->d_name.len,
+ &uname);
+ if (uname_len < 0) {
+ if (uname_len != -ENAMETOOLONG)
+ ntfs_error(vol->sb, "Failed to convert name to "
+ "Unicode.");
+ return ERR_PTR(uname_len);
+ }
+ mref = ntfs_lookup_inode_by_name(NTFS_I(dir_ino), uname, uname_len,
+ &name);
+ kmem_cache_free(ntfs_name_cache, uname);
+ if (!IS_ERR_MREF(mref)) {
+ dent_ino = MREF(mref);
+ ntfs_debug("Found inode 0x%lx. Calling ntfs_iget.", dent_ino);
+ dent_inode = ntfs_iget(vol->sb, dent_ino);
+ if (!IS_ERR(dent_inode)) {
+ /* Consistency check. */
+ if (is_bad_inode(dent_inode) || MSEQNO(mref) ==
+ NTFS_I(dent_inode)->seq_no ||
+ dent_ino == FILE_MFT) {
+ /* Perfect WIN32/POSIX match. -- Case 1. */
+ if (!name) {
+ ntfs_debug("Done. (Case 1.)");
+ return d_splice_alias(dent_inode, dent);
+ }
+ /*
+ * We are too indented. Handle imperfect
+ * matches and short file names further below.
+ */
+ goto handle_name;
+ }
+ ntfs_error(vol->sb, "Found stale reference to inode "
+ "0x%lx (reference sequence number = "
+ "0x%x, inode sequence number = 0x%x), "
+ "returning -EIO. Run chkdsk.",
+ dent_ino, MSEQNO(mref),
+ NTFS_I(dent_inode)->seq_no);
+ iput(dent_inode);
+ dent_inode = ERR_PTR(-EIO);
+ } else
+ ntfs_error(vol->sb, "ntfs_iget(0x%lx) failed with "
+ "error code %li.", dent_ino,
+ PTR_ERR(dent_inode));
+ kfree(name);
+ /* Return the error code. */
+ return ERR_CAST(dent_inode);
+ }
+ /* It is guaranteed that @name is no longer allocated at this point. */
+ if (MREF_ERR(mref) == -ENOENT) {
+ ntfs_debug("Entry was not found, adding negative dentry.");
+ /* The dcache will handle negative entries. */
+ d_add(dent, NULL);
+ ntfs_debug("Done.");
+ return NULL;
+ }
+ ntfs_error(vol->sb, "ntfs_lookup_ino_by_name() failed with error "
+ "code %i.", -MREF_ERR(mref));
+ return ERR_PTR(MREF_ERR(mref));
+ // TODO: Consider moving this lot to a separate function! (AIA)
+handle_name:
+ {
+ MFT_RECORD *m;
+ ntfs_attr_search_ctx *ctx;
+ ntfs_inode *ni = NTFS_I(dent_inode);
+ int err;
+ struct qstr nls_name;
+
+ nls_name.name = NULL;
+ if (name->type != FILE_NAME_DOS) { /* Case 2. */
+ ntfs_debug("Case 2.");
+ nls_name.len = (unsigned)ntfs_ucstonls(vol,
+ (ntfschar*)&name->name, name->len,
+ (unsigned char**)&nls_name.name, 0);
+ kfree(name);
+ } else /* if (name->type == FILE_NAME_DOS) */ { /* Case 3. */
+ FILE_NAME_ATTR *fn;
+
+ ntfs_debug("Case 3.");
+ kfree(name);
+
+ /* Find the WIN32 name corresponding to the matched DOS name. */
+ ni = NTFS_I(dent_inode);
+ m = map_mft_record(ni);
+ if (IS_ERR(m)) {
+ err = PTR_ERR(m);
+ m = NULL;
+ ctx = NULL;
+ goto err_out;
+ }
+ ctx = ntfs_attr_get_search_ctx(ni, m);
+ if (unlikely(!ctx)) {
+ err = -ENOMEM;
+ goto err_out;
+ }
+ do {
+ ATTR_RECORD *a;
+ u32 val_len;
+
+ err = ntfs_attr_lookup(AT_FILE_NAME, NULL, 0, 0, 0,
+ NULL, 0, ctx);
+ if (unlikely(err)) {
+ ntfs_error(vol->sb, "Inode corrupt: No WIN32 "
+ "namespace counterpart to DOS "
+ "file name. Run chkdsk.");
+ if (err == -ENOENT)
+ err = -EIO;
+ goto err_out;
+ }
+ /* Consistency checks. */
+ a = ctx->attr;
+ if (a->non_resident || a->flags)
+ goto eio_err_out;
+ val_len = le32_to_cpu(a->data.resident.value_length);
+ if (le16_to_cpu(a->data.resident.value_offset) +
+ val_len > le32_to_cpu(a->length))
+ goto eio_err_out;
+ fn = (FILE_NAME_ATTR*)((u8*)ctx->attr + le16_to_cpu(
+ ctx->attr->data.resident.value_offset));
+ if ((u32)(fn->file_name_length * sizeof(ntfschar) +
+ sizeof(FILE_NAME_ATTR)) > val_len)
+ goto eio_err_out;
+ } while (fn->file_name_type != FILE_NAME_WIN32);
+
+ /* Convert the found WIN32 name to current NLS code page. */
+ nls_name.len = (unsigned)ntfs_ucstonls(vol,
+ (ntfschar*)&fn->file_name, fn->file_name_length,
+ (unsigned char**)&nls_name.name, 0);
+
+ ntfs_attr_put_search_ctx(ctx);
+ unmap_mft_record(ni);
+ }
+ m = NULL;
+ ctx = NULL;
+
+ /* Check if a conversion error occurred. */
+ if ((signed)nls_name.len < 0) {
+ err = (signed)nls_name.len;
+ goto err_out;
+ }
+ nls_name.hash = full_name_hash(dent, nls_name.name, nls_name.len);
+
+ dent = d_add_ci(dent, dent_inode, &nls_name);
+ kfree(nls_name.name);
+ return dent;
+
+eio_err_out:
+ ntfs_error(vol->sb, "Illegal file name attribute. Run chkdsk.");
+ err = -EIO;
+err_out:
+ if (ctx)
+ ntfs_attr_put_search_ctx(ctx);
+ if (m)
+ unmap_mft_record(ni);
+ iput(dent_inode);
+ ntfs_error(vol->sb, "Failed, returning error code %i.", err);
+ return ERR_PTR(err);
+ }
+}
+
+/*
+ * Inode operations for directories.
+ */
+const struct inode_operations ntfs_dir_inode_ops = {
+ .lookup = ntfs_lookup, /* VFS: Lookup directory. */
+};
+
+/**
+ * ntfs_get_parent - find the dentry of the parent of a given directory dentry
+ * @child_dent: dentry of the directory whose parent directory to find
+ *
+ * Find the dentry for the parent directory of the directory specified by the
+ * dentry @child_dent. This function is called from
+ * fs/exportfs/expfs.c::find_exported_dentry() which in turn is called from the
+ * default ->decode_fh() which is export_decode_fh() in the same file.
+ *
+ * The code is based on the ext3 ->get_parent() implementation found in
+ * fs/ext3/namei.c::ext3_get_parent().
+ *
+ * Note: ntfs_get_parent() is called with @d_inode(child_dent)->i_mutex down.
+ *
+ * Return the dentry of the parent directory on success or the error code on
+ * error (IS_ERR() is true).
+ */
+static struct dentry *ntfs_get_parent(struct dentry *child_dent)
+{
+ struct inode *vi = d_inode(child_dent);
+ ntfs_inode *ni = NTFS_I(vi);
+ MFT_RECORD *mrec;
+ ntfs_attr_search_ctx *ctx;
+ ATTR_RECORD *attr;
+ FILE_NAME_ATTR *fn;
+ unsigned long parent_ino;
+ int err;
+
+ ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
+ /* Get the mft record of the inode belonging to the child dentry. */
+ mrec = map_mft_record(ni);
+ if (IS_ERR(mrec))
+ return ERR_CAST(mrec);
+ /* Find the first file name attribute in the mft record. */
+ ctx = ntfs_attr_get_search_ctx(ni, mrec);
+ if (unlikely(!ctx)) {
+ unmap_mft_record(ni);
+ return ERR_PTR(-ENOMEM);
+ }
+try_next:
+ err = ntfs_attr_lookup(AT_FILE_NAME, NULL, 0, CASE_SENSITIVE, 0, NULL,
+ 0, ctx);
+ if (unlikely(err)) {
+ ntfs_attr_put_search_ctx(ctx);
+ unmap_mft_record(ni);
+ if (err == -ENOENT)
+ ntfs_error(vi->i_sb, "Inode 0x%lx does not have a "
+ "file name attribute. Run chkdsk.",
+ vi->i_ino);
+ return ERR_PTR(err);
+ }
+ attr = ctx->attr;
+ if (unlikely(attr->non_resident))
+ goto try_next;
+ fn = (FILE_NAME_ATTR *)((u8 *)attr +
+ le16_to_cpu(attr->data.resident.value_offset));
+ if (unlikely((u8 *)fn + le32_to_cpu(attr->data.resident.value_length) >
+ (u8*)attr + le32_to_cpu(attr->length)))
+ goto try_next;
+ /* Get the inode number of the parent directory. */
+ parent_ino = MREF_LE(fn->parent_directory);
+ /* Release the search context and the mft record of the child. */
+ ntfs_attr_put_search_ctx(ctx);
+ unmap_mft_record(ni);
+
+ return d_obtain_alias(ntfs_iget(vi->i_sb, parent_ino));
+}
+
+static struct inode *ntfs_nfs_get_inode(struct super_block *sb,
+ u64 ino, u32 generation)
+{
+ struct inode *inode;
+
+ inode = ntfs_iget(sb, ino);
+ if (!IS_ERR(inode)) {
+ if (is_bad_inode(inode) || inode->i_generation != generation) {
+ iput(inode);
+ inode = ERR_PTR(-ESTALE);
+ }
+ }
+
+ return inode;
+}
+
+static struct dentry *ntfs_fh_to_dentry(struct super_block *sb, struct fid *fid,
+ int fh_len, int fh_type)
+{
+ return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+ ntfs_nfs_get_inode);
+}
+
+static struct dentry *ntfs_fh_to_parent(struct super_block *sb, struct fid *fid,
+ int fh_len, int fh_type)
+{
+ return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+ ntfs_nfs_get_inode);
+}
+
+/*
+ * Export operations allowing NFS exporting of mounted NTFS partitions.
+ *
+ * We use the default ->encode_fh() for now. Note that they
+ * use 32 bits to store the inode number which is an unsigned long so on 64-bit
+ * architectures is usually 64 bits so it would all fail horribly on huge
+ * volumes. I guess we need to define our own encode and decode fh functions
+ * that store 64-bit inode numbers at some point but for now we will ignore the
+ * problem...
+ *
+ * We also use the default ->get_name() helper (used by ->decode_fh() via
+ * fs/exportfs/expfs.c::find_exported_dentry()) as that is completely fs
+ * independent.
+ *
+ * The default ->get_parent() just returns -EACCES so we have to provide our
+ * own and the default ->get_dentry() is incompatible with NTFS due to not
+ * allowing the inode number 0 which is used in NTFS for the system file $MFT
+ * and due to using iget() whereas NTFS needs ntfs_iget().
+ */
+const struct export_operations ntfs_export_ops = {
+ .get_parent = ntfs_get_parent, /* Find the parent of a given
+ directory. */
+ .fh_to_dentry = ntfs_fh_to_dentry,
+ .fh_to_parent = ntfs_fh_to_parent,
+};
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