fs/ntfs3: Add attrib operations

// SPDX-License-Identifier: GPL-2.0

/*

 *

 * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.

 *

 */

#include <linux/blkdev.h>

#include <linux/buffer_head.h>

#include <linux/fs.h>

#include <linux/nls.h>

#include "debug.h"

#include "ntfs.h"

#include "ntfs_fs.h"

/* Returns 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);

	ntfs_free(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);

		le = ntfs_malloc(al_aligned(lsize));

		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);

		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;

		le = ntfs_malloc(al_aligned(lsize));

		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

 *

 * Returns the next list 'le'

 * if 'le' is NULL then returns 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

 *

 * finds the first 'le' in the list which matches type, name and vcn

 * Returns 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

 *

 * finds the first 'le' in the list which matches type, name and vcn

 * Returns 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

 *

 * finds 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, 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

 *

 * adds 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;

	u64 new_size;

	typeof(ni->attr_list) *al = &ni->attr_list;

	/*

	 * Compute the size of the new 'le'

	 */

	sz = le_size(name_len);

	new_size = al->size + sz;

	asize = al_aligned(al->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 = ntfs_malloc(new_asize);

		if (!ptr)

			return -ENOMEM;

		memcpy(ptr, al->le, off);

		memcpy(Add2Ptr(ptr, off + sz), le, al->size - off);

		le = Add2Ptr(ptr, off);

		ntfs_free(al->le);

		al->le = ptr;

	} else {

		memmove(Add2Ptr(le, sz), le, al->size - off);

	}

	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);

	al->dirty = true;

	err = attr_set_size(ni, ATTR_LIST, NULL, 0, &al->run, new_size,

			    &new_size, true, &attr);

	if (err)

		return err;

	if (attr && attr->non_res) {

		err = ntfs_sb_write_run(ni->mi.sbi, &al->run, 0, al->le,

					al->size);

		if (err)

			return err;

	}

	al->dirty = false;

	*new_le = le;

	return 0;

}

/*

 * al_remove_le

 *

 * removes '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

 *

 * deletes from the list the first 'le' 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 'le'. */

	memmove(le, Add2Ptr(le, size), al->size - (off + size));

	al->size -= size;

	al->dirty = true;

	return true;

}

/*

 * al_update

 */

int al_update(struct ntfs_inode *ni)

{

	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);

		if (err)

			goto out;

		attr->nres.valid_size = attr->nres.data_size;

	}

	ni->mi.dirty = true;

	al->dirty = false;

out:

	return err;

}