int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
{
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct ext4_super_block *es = sbi->s_es;
	int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
		le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
	struct buffer_head *primary = NULL;
	struct ext4_group_desc *gdp;
	struct inode *inode = NULL;
	handle_t *handle;
	int gdb_off, gdb_num;
	int num_grp_locked = 0;
	int err, err2;

	gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
	gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);

	if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
					EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
		ext4_warning(sb, __func__,
			     "Can't resize non-sparse filesystem further");
		return -EPERM;
	}

	if (ext4_blocks_count(es) + input->blocks_count <
	    ext4_blocks_count(es)) {
		ext4_warning(sb, __func__, "blocks_count overflow");
		return -EINVAL;
	}

	if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
	    le32_to_cpu(es->s_inodes_count)) {
		ext4_warning(sb, __func__, "inodes_count overflow");
		return -EINVAL;
	}

	if (reserved_gdb || gdb_off == 0) {
		if (!EXT4_HAS_COMPAT_FEATURE(sb,
					     EXT4_FEATURE_COMPAT_RESIZE_INODE)
		    || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
			ext4_warning(sb, __func__,
				     "No reserved GDT blocks, can't resize");
			return -EPERM;
		}
		inode = ext4_iget(sb, EXT4_RESIZE_INO);
		if (IS_ERR(inode)) {
			ext4_warning(sb, __func__,
				     "Error opening resize inode");
			return PTR_ERR(inode);
		}
	}

	if ((err = verify_group_input(sb, input)))
		goto exit_put;

	if ((err = setup_new_group_blocks(sb, input)))
		goto exit_put;

	/*
	 * We will always be modifying at least the superblock and a GDT
	 * block.  If we are adding a group past the last current GDT block,
	 * we will also modify the inode and the dindirect block.  If we
	 * are adding a group with superblock/GDT backups  we will also
	 * modify each of the reserved GDT dindirect blocks.
	 */
	handle = ext4_journal_start_sb(sb,
				       ext4_bg_has_super(sb, input->group) ?
				       3 + reserved_gdb : 4);
	if (IS_ERR(handle)) {
		err = PTR_ERR(handle);
		goto exit_put;
	}

	lock_super(sb);
	if (input->group != sbi->s_groups_count) {
		ext4_warning(sb, __func__,
			     "multiple resizers run on filesystem!");
		err = -EBUSY;
		goto exit_journal;
	}

	if ((err = ext4_journal_get_write_access(handle, sbi->s_sbh)))
		goto exit_journal;

        /*
         * We will only either add reserved group blocks to a backup group
         * or remove reserved blocks for the first group in a new group block.
         * Doing both would be mean more complex code, and sane people don't
         * use non-sparse filesystems anymore.  This is already checked above.
         */
	if (gdb_off) {
		primary = sbi->s_group_desc[gdb_num];
		if ((err = ext4_journal_get_write_access(handle, primary)))
			goto exit_journal;

		if (reserved_gdb && ext4_bg_num_gdb(sb, input->group) &&
		    (err = reserve_backup_gdb(handle, inode, input)))
			goto exit_journal;
	} else if ((err = add_new_gdb(handle, inode, input, &primary)))
		goto exit_journal;

        /*
         * OK, now we've set up the new group.  Time to make it active.
         *
         * Current kernels don't lock all allocations via lock_super(),
         * so we have to be safe wrt. concurrent accesses the group
         * data.  So we need to be careful to set all of the relevant
         * group descriptor data etc. *before* we enable the group.
         *
         * The key field here is sbi->s_groups_count: as long as
         * that retains its old value, nobody is going to access the new
         * group.
         *
         * So first we update all the descriptor metadata for the new
         * group; then we update the total disk blocks count; then we
         * update the groups count to enable the group; then finally we
         * update the free space counts so that the system can start
         * using the new disk blocks.
         */

	num_grp_locked = ext4_mb_get_buddy_cache_lock(sb, input->group);
	/* Update group descriptor block for new group */
	gdp = (struct ext4_group_desc *)((char *)primary->b_data +
					 gdb_off * EXT4_DESC_SIZE(sb));

	memset(gdp, 0, EXT4_DESC_SIZE(sb));
	ext4_block_bitmap_set(sb, gdp, input->block_bitmap); /* LV FIXME */
	ext4_inode_bitmap_set(sb, gdp, input->inode_bitmap); /* LV FIXME */
	ext4_inode_table_set(sb, gdp, input->inode_table); /* LV FIXME */
	ext4_free_blks_set(sb, gdp, input->free_blocks_count);
	ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
	gdp->bg_flags = cpu_to_le16(EXT4_BG_INODE_ZEROED);
	gdp->bg_checksum = ext4_group_desc_csum(sbi, input->group, gdp);

	/*
	 * We can allocate memory for mb_alloc based on the new group
	 * descriptor
	 */
	err = ext4_mb_add_groupinfo(sb, input->group, gdp);
	if (err) {
		ext4_mb_put_buddy_cache_lock(sb, input->group, num_grp_locked);
		goto exit_journal;
	}

	/*
	 * Make the new blocks and inodes valid next.  We do this before
	 * increasing the group count so that once the group is enabled,
	 * all of its blocks and inodes are already valid.
	 *
	 * We always allocate group-by-group, then block-by-block or
	 * inode-by-inode within a group, so enabling these
	 * blocks/inodes before the group is live won't actually let us
	 * allocate the new space yet.
	 */
	ext4_blocks_count_set(es, ext4_blocks_count(es) +
		input->blocks_count);
	le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb));

	/*
	 * We need to protect s_groups_count against other CPUs seeing
	 * inconsistent state in the superblock.
	 *
	 * The precise rules we use are:
	 *
	 * * Writers of s_groups_count *must* hold lock_super
	 * AND
	 * * Writers must perform a smp_wmb() after updating all dependent
	 *   data and before modifying the groups count
	 *
	 * * Readers must hold lock_super() over the access
	 * OR
	 * * Readers must perform an smp_rmb() after reading the groups count
	 *   and before reading any dependent data.
	 *
	 * NB. These rules can be relaxed when checking the group count
	 * while freeing data, as we can only allocate from a block
	 * group after serialising against the group count, and we can
	 * only then free after serialising in turn against that
	 * allocation.
	 */
	smp_wmb();

	/* Update the global fs size fields */
	sbi->s_groups_count++;
	ext4_mb_put_buddy_cache_lock(sb, input->group, num_grp_locked);

	ext4_handle_dirty_metadata(handle, NULL, primary);

	/* Update the reserved block counts only once the new group is
	 * active. */
	ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
		input->reserved_blocks);

	/* Update the free space counts */
	percpu_counter_add(&sbi->s_freeblocks_counter,
			   input->free_blocks_count);
	percpu_counter_add(&sbi->s_freeinodes_counter,
			   EXT4_INODES_PER_GROUP(sb));

	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
		ext4_group_t flex_group;
		flex_group = ext4_flex_group(sbi, input->group);
		sbi->s_flex_groups[flex_group].free_blocks +=
			input->free_blocks_count;
		sbi->s_flex_groups[flex_group].free_inodes +=
			EXT4_INODES_PER_GROUP(sb);
	}

	ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
	sb->s_dirt = 1;

exit_journal:
	unlock_super(sb);
	if ((err2 = ext4_journal_stop(handle)) && !err)
		err = err2;
	if (!err) {
		update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
			       sizeof(struct ext4_super_block));
		update_backups(sb, primary->b_blocknr, primary->b_data,
			       primary->b_size);
	}
exit_put:
	iput(inode);
	return err;
} /* ext4_group_add */

ext4: Initialize the new group descriptor when resizing the filesystem

Make sure all of the fields of the group descriptor are properly
initialized.  Previously, we allowed bg_flags field to be contain
random garbage, which could trigger non-deterministic behavior,
including a kernel OOPS.

http://bugzilla.kernel.org/show_bug.cgi?id=12433

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org


static void update_backups(struct super_block *sb,
			   int blk_off, char *data, int size)
{
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	const ext4_group_t last = sbi->s_groups_count;
	const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
	unsigned three = 1;
	unsigned five = 5;
	unsigned seven = 7;
	ext4_group_t group;
	int rest = sb->s_blocksize - size;
	handle_t *handle;
	int err = 0, err2;

	handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
	if (IS_ERR(handle)) {
		group = 1;
		err = PTR_ERR(handle);
		goto exit_err;
	}

	while ((group = ext4_list_backups(sb, &three, &five, &seven)) < last) {
		struct buffer_head *bh;

		/* Out of journal space, and can't get more - abort - so sad */
		if (ext4_handle_valid(handle) &&
		    handle->h_buffer_credits == 0 &&
		    ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
		    (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
			break;

		bh = sb_getblk(sb, group * bpg + blk_off);
		if (!bh) {
			err = -EIO;
			break;
		}
		ext4_debug("update metadata backup %#04lx\n",
			  (unsigned long)bh->b_blocknr);
		if ((err = ext4_journal_get_write_access(handle, bh)))
			break;
		lock_buffer(bh);
		memcpy(bh->b_data, data, size);
		if (rest)
			memset(bh->b_data + size, 0, rest);
		set_buffer_uptodate(bh);
		unlock_buffer(bh);
		ext4_handle_dirty_metadata(handle, NULL, bh);
		brelse(bh);
	}
	if ((err2 = ext4_journal_stop(handle)) && !err)
		err = err2;

	/*
	 * Ugh! Need to have e2fsck write the backup copies.  It is too
	 * late to revert the resize, we shouldn't fail just because of
	 * the backup copies (they are only needed in case of corruption).
	 *
	 * However, if we got here we have a journal problem too, so we
	 * can't really start a transaction to mark the superblock.
	 * Chicken out and just set the flag on the hope it will be written
	 * to disk, and if not - we will simply wait until next fsck.
	 */
exit_err:
	if (err) {
		ext4_warning(sb, __func__,
			     "can't update backup for group %u (err %d), "
			     "forcing fsck on next reboot", group, err);
		sbi->s_mount_state &= ~EXT4_VALID_FS;
		sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
		mark_buffer_dirty(sbi->s_sbh);
	}
}


int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
		      ext4_fsblk_t n_blocks_count)
{
	ext4_fsblk_t o_blocks_count;
	ext4_group_t o_groups_count;
	ext4_grpblk_t last;
	ext4_grpblk_t add;
	struct buffer_head *bh;
	handle_t *handle;
	int err;
	ext4_group_t group;

	/* We don't need to worry about locking wrt other resizers just
	 * yet: we're going to revalidate es->s_blocks_count after
	 * taking lock_super() below. */
	o_blocks_count = ext4_blocks_count(es);
	o_groups_count = EXT4_SB(sb)->s_groups_count;

	if (test_opt(sb, DEBUG))
		printk(KERN_DEBUG "EXT4-fs: extending last group from %llu uto %llu blocks\n",
		       o_blocks_count, n_blocks_count);

	if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
		return 0;

	if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
		printk(KERN_ERR "EXT4-fs: filesystem on %s:"
			" too large to resize to %llu blocks safely\n",
			sb->s_id, n_blocks_count);
		if (sizeof(sector_t) < 8)
			ext4_warning(sb, __func__, "CONFIG_LBD not enabled");
		return -EINVAL;
	}

	if (n_blocks_count < o_blocks_count) {
		ext4_warning(sb, __func__,
			     "can't shrink FS - resize aborted");
		return -EBUSY;
	}

	/* Handle the remaining blocks in the last group only. */
	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);

	if (last == 0) {
		ext4_warning(sb, __func__,
			     "need to use ext2online to resize further");
		return -EPERM;
	}

	add = EXT4_BLOCKS_PER_GROUP(sb) - last;

	if (o_blocks_count + add < o_blocks_count) {
		ext4_warning(sb, __func__, "blocks_count overflow");
		return -EINVAL;
	}

	if (o_blocks_count + add > n_blocks_count)
		add = n_blocks_count - o_blocks_count;

	if (o_blocks_count + add < n_blocks_count)
		ext4_warning(sb, __func__,
			     "will only finish group (%llu"
			     " blocks, %u new)",
			     o_blocks_count + add, add);

	/* See if the device is actually as big as what was requested */
	bh = sb_bread(sb, o_blocks_count + add - 1);
	if (!bh) {
		ext4_warning(sb, __func__,
			     "can't read last block, resize aborted");
		return -ENOSPC;
	}
	brelse(bh);

	/* We will update the superblock, one block bitmap, and
	 * one group descriptor via ext4_free_blocks().
	 */
	handle = ext4_journal_start_sb(sb, 3);
	if (IS_ERR(handle)) {
		err = PTR_ERR(handle);
		ext4_warning(sb, __func__, "error %d on journal start", err);
		goto exit_put;
	}

	lock_super(sb);
	if (o_blocks_count != ext4_blocks_count(es)) {
		ext4_warning(sb, __func__,
			     "multiple resizers run on filesystem!");
		unlock_super(sb);
		ext4_journal_stop(handle);
		err = -EBUSY;
		goto exit_put;
	}

	if ((err = ext4_journal_get_write_access(handle,
						 EXT4_SB(sb)->s_sbh))) {
		ext4_warning(sb, __func__,
			     "error %d on journal write access", err);
		unlock_super(sb);
		ext4_journal_stop(handle);
		goto exit_put;
	}
	ext4_blocks_count_set(es, o_blocks_count + add);
	ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
	sb->s_dirt = 1;
	unlock_super(sb);
	ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
		   o_blocks_count + add);
	/* We add the blocks to the bitmap and set the group need init bit */
	ext4_add_groupblocks(handle, sb, o_blocks_count, add);
	ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
		   o_blocks_count + add);
	if ((err = ext4_journal_stop(handle)))
		goto exit_put;

	if (test_opt(sb, DEBUG))
		printk(KERN_DEBUG "EXT4-fs: extended group to %llu blocks\n",
		       ext4_blocks_count(es));
	update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es,
		       sizeof(struct ext4_super_block));
exit_put:
	return err;
} /* ext4_group_extend */


static int add_new_gdb(handle_t *handle, struct inode *inode,
		       struct ext4_new_group_data *input,
		       struct buffer_head **primary)
{
	struct super_block *sb = inode->i_sb;
	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
	unsigned long gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
	ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
	struct buffer_head **o_group_desc, **n_group_desc;
	struct buffer_head *dind;
	int gdbackups;
	struct ext4_iloc iloc;
	__le32 *data;
	int err;

	if (test_opt(sb, DEBUG))
		printk(KERN_DEBUG
		       "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
		       gdb_num);

	/*
	 * If we are not using the primary superblock/GDT copy don't resize,
         * because the user tools have no way of handling this.  Probably a
         * bad time to do it anyways.
         */
	if (EXT4_SB(sb)->s_sbh->b_blocknr !=
	    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
		ext4_warning(sb, __func__,
			"won't resize using backup superblock at %llu",
			(unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
		return -EPERM;
	}

	*primary = sb_bread(sb, gdblock);
	if (!*primary)
		return -EIO;

	if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) {
		err = gdbackups;
		goto exit_bh;
	}

	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
	dind = sb_bread(sb, le32_to_cpu(*data));
	if (!dind) {
		err = -EIO;
		goto exit_bh;
	}

	data = (__le32 *)dind->b_data;
	if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
		ext4_warning(sb, __func__,
			     "new group %u GDT block %llu not reserved",
			     input->group, gdblock);
		err = -EINVAL;
		goto exit_dind;
	}

	if ((err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh)))
		goto exit_dind;

	if ((err = ext4_journal_get_write_access(handle, *primary)))
		goto exit_sbh;

	if ((err = ext4_journal_get_write_access(handle, dind)))
		goto exit_primary;

	/* ext4_reserve_inode_write() gets a reference on the iloc */
	if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
		goto exit_dindj;

	n_group_desc = kmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
			GFP_NOFS);
	if (!n_group_desc) {
		err = -ENOMEM;
		ext4_warning(sb, __func__,
			      "not enough memory for %lu groups", gdb_num + 1);
		goto exit_inode;
	}

	/*
	 * Finally, we have all of the possible failures behind us...
	 *
	 * Remove new GDT block from inode double-indirect block and clear out
	 * the new GDT block for use (which also "frees" the backup GDT blocks
	 * from the reserved inode).  We don't need to change the bitmaps for
	 * these blocks, because they are marked as in-use from being in the
	 * reserved inode, and will become GDT blocks (primary and backup).
	 */
	data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
	ext4_handle_dirty_metadata(handle, NULL, dind);
	brelse(dind);
	inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
	ext4_mark_iloc_dirty(handle, inode, &iloc);
	memset((*primary)->b_data, 0, sb->s_blocksize);
	ext4_handle_dirty_metadata(handle, NULL, *primary);

	o_group_desc = EXT4_SB(sb)->s_group_desc;
	memcpy(n_group_desc, o_group_desc,
	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
	n_group_desc[gdb_num] = *primary;
	EXT4_SB(sb)->s_group_desc = n_group_desc;
	EXT4_SB(sb)->s_gdb_count++;
	kfree(o_group_desc);

	le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
	ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);

	return 0;

exit_inode:
	/* ext4_journal_release_buffer(handle, iloc.bh); */
	brelse(iloc.bh);
exit_dindj:
	/* ext4_journal_release_buffer(handle, dind); */
exit_primary:
	/* ext4_journal_release_buffer(handle, *primary); */
exit_sbh:
	/* ext4_journal_release_buffer(handle, *primary); */
exit_dind:
	brelse(dind);
exit_bh:
	brelse(*primary);

	ext4_debug("leaving with error %d\n", err);
	return err;
}


static int extend_or_restart_transaction(handle_t *handle, int thresh,
					 struct buffer_head *bh)
{
	int err;

	if (ext4_handle_has_enough_credits(handle, thresh))
		return 0;

	err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
	if (err < 0)
		return err;
	if (err) {
		if ((err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
			return err;
		if ((err = ext4_journal_get_write_access(handle, bh)))
			return err;
	}

	return 0;
}


static int verify_reserved_gdb(struct super_block *sb,
			       struct buffer_head *primary)
{
	const ext4_fsblk_t blk = primary->b_blocknr;
	const ext4_group_t end = EXT4_SB(sb)->s_groups_count;
	unsigned three = 1;
	unsigned five = 5;
	unsigned seven = 7;
	unsigned grp;
	__le32 *p = (__le32 *)primary->b_data;
	int gdbackups = 0;

	while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
		if (le32_to_cpu(*p++) !=
		    grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
			ext4_warning(sb, __func__,
				     "reserved GDT %llu"
				     " missing grp %d (%llu)",
				     blk, grp,
				     grp *
				     (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
				     blk);
			return -EINVAL;
		}
		if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
			return -EFBIG;
	}

	return gdbackups;
}


static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
			      struct ext4_new_group_data *input)
{
	struct super_block *sb = inode->i_sb;
	int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
	struct buffer_head **primary;
	struct buffer_head *dind;
	struct ext4_iloc iloc;
	ext4_fsblk_t blk;
	__le32 *data, *end;
	int gdbackups = 0;
	int res, i;
	int err;

	primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
	if (!primary)
		return -ENOMEM;

	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
	dind = sb_bread(sb, le32_to_cpu(*data));
	if (!dind) {
		err = -EIO;
		goto exit_free;
	}

	blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
	data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
					 EXT4_ADDR_PER_BLOCK(sb));
	end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);

	/* Get each reserved primary GDT block and verify it holds backups */
	for (res = 0; res < reserved_gdb; res++, blk++) {
		if (le32_to_cpu(*data) != blk) {
			ext4_warning(sb, __func__,
				     "reserved block %llu"
				     " not at offset %ld",
				     blk,
				     (long)(data - (__le32 *)dind->b_data));
			err = -EINVAL;
			goto exit_bh;
		}
		primary[res] = sb_bread(sb, blk);
		if (!primary[res]) {
			err = -EIO;
			goto exit_bh;
		}
		if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
			brelse(primary[res]);
			err = gdbackups;
			goto exit_bh;
		}
		if (++data >= end)
			data = (__le32 *)dind->b_data;
	}

	for (i = 0; i < reserved_gdb; i++) {
		if ((err = ext4_journal_get_write_access(handle, primary[i]))) {
			/*
			int j;
			for (j = 0; j < i; j++)
				ext4_journal_release_buffer(handle, primary[j]);
			 */
			goto exit_bh;
		}
	}

	if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
		goto exit_bh;

	/*
	 * Finally we can add each of the reserved backup GDT blocks from
	 * the new group to its reserved primary GDT block.
	 */
	blk = input->group * EXT4_BLOCKS_PER_GROUP(sb);
	for (i = 0; i < reserved_gdb; i++) {
		int err2;
		data = (__le32 *)primary[i]->b_data;
		/* printk("reserving backup %lu[%u] = %lu\n",
		       primary[i]->b_blocknr, gdbackups,
		       blk + primary[i]->b_blocknr); */
		data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
		err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
		if (!err)
			err = err2;
	}
	inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
	ext4_mark_iloc_dirty(handle, inode, &iloc);

exit_bh:
	while (--res >= 0)
		brelse(primary[res]);
	brelse(dind);

exit_free:
	kfree(primary);

	return err;
}


static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
				  ext4_fsblk_t blk)
{
	struct buffer_head *bh;
	int err;

	bh = sb_getblk(sb, blk);
	if (!bh)
		return ERR_PTR(-EIO);
	if ((err = ext4_journal_get_write_access(handle, bh))) {
		brelse(bh);
		bh = ERR_PTR(err);
	} else {
		lock_buffer(bh);
		memset(bh->b_data, 0, sb->s_blocksize);
		set_buffer_uptodate(bh);
		unlock_buffer(bh);
	}

	return bh;
}


static int setup_new_group_blocks(struct super_block *sb,
				  struct ext4_new_group_data *input)
{
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	ext4_fsblk_t start = ext4_group_first_block_no(sb, input->group);
	int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
		le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
	unsigned long gdblocks = ext4_bg_num_gdb(sb, input->group);
	struct buffer_head *bh;
	handle_t *handle;
	ext4_fsblk_t block;
	ext4_grpblk_t bit;
	int i;
	int err = 0, err2;

	/* This transaction may be extended/restarted along the way */
	handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);

	if (IS_ERR(handle))
		return PTR_ERR(handle);

	lock_super(sb);
	if (input->group != sbi->s_groups_count) {
		err = -EBUSY;
		goto exit_journal;
	}

	if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
		err = PTR_ERR(bh);
		goto exit_journal;
	}

	if (ext4_bg_has_super(sb, input->group)) {
		ext4_debug("mark backup superblock %#04llx (+0)\n", start);
		ext4_set_bit(0, bh->b_data);
	}

	/* Copy all of the GDT blocks into the backup in this group */
	for (i = 0, bit = 1, block = start + 1;
	     i < gdblocks; i++, block++, bit++) {
		struct buffer_head *gdb;

		ext4_debug("update backup group %#04llx (+%d)\n", block, bit);

		if ((err = extend_or_restart_transaction(handle, 1, bh)))
			goto exit_bh;

		gdb = sb_getblk(sb, block);
		if (!gdb) {
			err = -EIO;
			goto exit_bh;
		}
		if ((err = ext4_journal_get_write_access(handle, gdb))) {
			brelse(gdb);
			goto exit_bh;
		}
		lock_buffer(gdb);
		memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, gdb->b_size);
		set_buffer_uptodate(gdb);
		unlock_buffer(gdb);
		ext4_handle_dirty_metadata(handle, NULL, gdb);
		ext4_set_bit(bit, bh->b_data);
		brelse(gdb);
	}

	/* Zero out all of the reserved backup group descriptor table blocks */
	for (i = 0, bit = gdblocks + 1, block = start + bit;
	     i < reserved_gdb; i++, block++, bit++) {
		struct buffer_head *gdb;

		ext4_debug("clear reserved block %#04llx (+%d)\n", block, bit);

		if ((err = extend_or_restart_transaction(handle, 1, bh)))
			goto exit_bh;

		if (IS_ERR(gdb = bclean(handle, sb, block))) {
			err = PTR_ERR(bh);
			goto exit_bh;
		}
		ext4_handle_dirty_metadata(handle, NULL, gdb);
		ext4_set_bit(bit, bh->b_data);
		brelse(gdb);
	}
	ext4_debug("mark block bitmap %#04llx (+%llu)\n", input->block_bitmap,
		   input->block_bitmap - start);
	ext4_set_bit(input->block_bitmap - start, bh->b_data);
	ext4_debug("mark inode bitmap %#04llx (+%llu)\n", input->inode_bitmap,
		   input->inode_bitmap - start);
	ext4_set_bit(input->inode_bitmap - start, bh->b_data);

	/* Zero out all of the inode table blocks */
	for (i = 0, block = input->inode_table, bit = block - start;
	     i < sbi->s_itb_per_group; i++, bit++, block++) {
		struct buffer_head *it;

		ext4_debug("clear inode block %#04llx (+%d)\n", block, bit);

		if ((err = extend_or_restart_transaction(handle, 1, bh)))
			goto exit_bh;

		if (IS_ERR(it = bclean(handle, sb, block))) {
			err = PTR_ERR(it);
			goto exit_bh;
		}
		ext4_handle_dirty_metadata(handle, NULL, it);
		brelse(it);
		ext4_set_bit(bit, bh->b_data);
	}

	if ((err = extend_or_restart_transaction(handle, 2, bh)))
		goto exit_bh;

	mark_bitmap_end(input->blocks_count, sb->s_blocksize * 8, bh->b_data);
	ext4_handle_dirty_metadata(handle, NULL, bh);
	brelse(bh);
	/* Mark unused entries in inode bitmap used */
	ext4_debug("clear inode bitmap %#04llx (+%llu)\n",
		   input->inode_bitmap, input->inode_bitmap - start);
	if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
		err = PTR_ERR(bh);
		goto exit_journal;
	}

	mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
			bh->b_data);
	ext4_handle_dirty_metadata(handle, NULL, bh);
exit_bh:
	brelse(bh);

exit_journal:
	unlock_super(sb);
	if ((err2 = ext4_journal_stop(handle)) && !err)
		err = err2;

	return err;
}


static int verify_group_input(struct super_block *sb,
			      struct ext4_new_group_data *input)
{
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct ext4_super_block *es = sbi->s_es;
	ext4_fsblk_t start = ext4_blocks_count(es);
	ext4_fsblk_t end = start + input->blocks_count;
	ext4_group_t group = input->group;
	ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
	unsigned overhead = ext4_bg_has_super(sb, group) ?
		(1 + ext4_bg_num_gdb(sb, group) +
		 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
	ext4_fsblk_t metaend = start + overhead;
	struct buffer_head *bh = NULL;
	ext4_grpblk_t free_blocks_count, offset;
	int err = -EINVAL;

	input->free_blocks_count = free_blocks_count =
		input->blocks_count - 2 - overhead - sbi->s_itb_per_group;

	if (test_opt(sb, DEBUG))
		printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
		       "(%d free, %u reserved)\n",
		       ext4_bg_has_super(sb, input->group) ? "normal" :
		       "no-super", input->group, input->blocks_count,
		       free_blocks_count, input->reserved_blocks);

	ext4_get_group_no_and_offset(sb, start, NULL, &offset);
	if (group != sbi->s_groups_count)
		ext4_warning(sb, __func__,
			     "Cannot add at group %u (only %u groups)",
			     input->group, sbi->s_groups_count);
	else if (offset != 0)
			ext4_warning(sb, __func__, "Last group not full");
	else if (input->reserved_blocks > input->blocks_count / 5)
		ext4_warning(sb, __func__, "Reserved blocks too high (%u)",
			     input->reserved_blocks);
	else if (free_blocks_count < 0)
		ext4_warning(sb, __func__, "Bad blocks count %u",
			     input->blocks_count);
	else if (!(bh = sb_bread(sb, end - 1)))
		ext4_warning(sb, __func__,
			     "Cannot read last block (%llu)",
			     end - 1);
	else if (outside(input->block_bitmap, start, end))
		ext4_warning(sb, __func__,
			     "Block bitmap not in group (block %llu)",
			     (unsigned long long)input->block_bitmap);
	else if (outside(input->inode_bitmap, start, end))
		ext4_warning(sb, __func__,
			     "Inode bitmap not in group (block %llu)",
			     (unsigned long long)input->inode_bitmap);
	else if (outside(input->inode_table, start, end) ||
		 outside(itend - 1, start, end))
		ext4_warning(sb, __func__,
			     "Inode table not in group (blocks %llu-%llu)",
			     (unsigned long long)input->inode_table, itend - 1);
	else if (input->inode_bitmap == input->block_bitmap)
		ext4_warning(sb, __func__,
			     "Block bitmap same as inode bitmap (%llu)",
			     (unsigned long long)input->block_bitmap);
	else if (inside(input->block_bitmap, input->inode_table, itend))
		ext4_warning(sb, __func__,
			     "Block bitmap (%llu) in inode table (%llu-%llu)",
			     (unsigned long long)input->block_bitmap,
			     (unsigned long long)input->inode_table, itend - 1);
	else if (inside(input->inode_bitmap, input->inode_table, itend))
		ext4_warning(sb, __func__,
			     "Inode bitmap (%llu) in inode table (%llu-%llu)",
			     (unsigned long long)input->inode_bitmap,
			     (unsigned long long)input->inode_table, itend - 1);
	else if (inside(input->block_bitmap, start, metaend))
		ext4_warning(sb, __func__,
			     "Block bitmap (%llu) in GDT table"
			     " (%llu-%llu)",
			     (unsigned long long)input->block_bitmap,
			     start, metaend - 1);
	else if (inside(input->inode_bitmap, start, metaend))
		ext4_warning(sb, __func__,
			     "Inode bitmap (%llu) in GDT table"
			     " (%llu-%llu)",
			     (unsigned long long)input->inode_bitmap,
			     start, metaend - 1);
	else if (inside(input->inode_table, start, metaend) ||
		 inside(itend - 1, start, metaend))
		ext4_warning(sb, __func__,
			     "Inode table (%llu-%llu) overlaps"
			     "GDT table (%llu-%llu)",
			     (unsigned long long)input->inode_table,
			     itend - 1, start, metaend - 1);
	else
		err = 0;
	brelse(bh);

	return err;
}


int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
{
	struct ecryptfs_crypt_stat *crypt_stat =
		&ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
	unsigned int order;
	char *virt;
	size_t virt_len;
	size_t size = 0;
	int rc = 0;

	if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
		if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
			printk(KERN_ERR "Key is invalid; bailing out\n");
			rc = -EINVAL;
			goto out;
		}
	} else {
		printk(KERN_WARNING "%s: Encrypted flag not set\n",
		       __func__);
		rc = -EINVAL;
		goto out;
	}
	virt_len = crypt_stat->num_header_bytes_at_front;
	order = get_order(virt_len);
	/* Released in this function */
	virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
	if (!virt) {
		printk(KERN_ERR "%s: Out of memory\n", __func__);
		rc = -ENOMEM;
		goto out;
	}
	rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
					 ecryptfs_dentry);
	if (unlikely(rc)) {
		printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
		       __func__, rc);
		goto out_free;
	}
	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
		rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
						      size);
	else
		rc = ecryptfs_write_metadata_to_contents(ecryptfs_dentry, virt,
							 virt_len);
	if (rc) {
		printk(KERN_ERR "%s: Error writing metadata out to lower file; "
		       "rc = [%d]\n", __func__, rc);
		goto out_free;
	}
out_free:
	free_pages((unsigned long)virt, order);
out:
	return rc;
}

eCryptfs: Allocate a variable number of pages for file headers

When allocating the memory used to store the eCryptfs header contents, a
single, zeroed page was being allocated with get_zeroed_page().
However, the size of an eCryptfs header is either PAGE_CACHE_SIZE or
ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE (8192), whichever is larger, and is
stored in the file's private_data->crypt_stat->num_header_bytes_at_front
field.

ecryptfs_write_metadata_to_contents() was using
num_header_bytes_at_front to decide how many bytes should be written to
the lower filesystem for the file header.  Unfortunately, at least 8K
was being written from the page, despite the chance of the single,
zeroed page being smaller than 8K.  This resulted in random areas of
kernel memory being written between the 0x1000 and 0x1FFF bytes offsets
in the eCryptfs file headers if PAGE_SIZE was 4K.

This patch allocates a variable number of pages, calculated with
num_header_bytes_at_front, and passes the number of allocated pages
along to ecryptfs_write_metadata_to_contents().

Thanks to Florian Streibelt for reporting the data leak and working with
me to find the problem.  2.6.28 is the only kernel release with this
vulnerability.  Corresponds to CVE-2009-0787

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Acked-by: Dustin Kirkland <kirkland@canonical.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Eugene Teo <eugeneteo@kernel.sg>
Cc: Greg KH <greg@kroah.com>
Cc: dann frazier <dannf@dannf.org>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Florian Streibelt <florian@f-streibelt.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>


int ecryptfs_decrypt_page(struct page *page)
{
	struct inode *ecryptfs_inode;
	struct ecryptfs_crypt_stat *crypt_stat;
	char *enc_extent_virt;
	struct page *enc_extent_page = NULL;
	unsigned long extent_offset;
	int rc = 0;

	ecryptfs_inode = page->mapping->host;
	crypt_stat =
		&(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
	if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
		rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
						      PAGE_CACHE_SIZE,
						      ecryptfs_inode);
		if (rc)
			printk(KERN_ERR "%s: Error attempting to copy "
			       "page at index [%ld]\n", __func__,
			       page->index);
		goto out;
	}
	enc_extent_page = alloc_page(GFP_USER);
	if (!enc_extent_page) {
		rc = -ENOMEM;
		ecryptfs_printk(KERN_ERR, "Error allocating memory for "
				"encrypted extent\n");
		goto out;
	}
	enc_extent_virt = kmap(enc_extent_page);
	for (extent_offset = 0;
	     extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
	     extent_offset++) {
		loff_t offset;

		ecryptfs_lower_offset_for_extent(
			&offset, ((page->index * (PAGE_CACHE_SIZE
						  / crypt_stat->extent_size))
				  + extent_offset), crypt_stat);
		rc = ecryptfs_read_lower(enc_extent_virt, offset,
					 crypt_stat->extent_size,
					 ecryptfs_inode);
		if (rc) {
			ecryptfs_printk(KERN_ERR, "Error attempting "
					"to read lower page; rc = [%d]"
					"\n", rc);
			goto out;
		}
		rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
					     extent_offset);
		if (rc) {
			printk(KERN_ERR "%s: Error encrypting extent; "
			       "rc = [%d]\n", __func__, rc);
			goto out;
		}
	}
out:
	if (enc_extent_page) {
		kunmap(enc_extent_page);
		__free_page(enc_extent_page);
	}
	return rc;
}


void ecryptfs_destroy_mount_crypt_stat(
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
{
	struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;

	if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
		return;
	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
	list_for_each_entry_safe(auth_tok, auth_tok_tmp,
				 &mount_crypt_stat->global_auth_tok_list,
				 mount_crypt_stat_list) {
		list_del(&auth_tok->mount_crypt_stat_list);
		mount_crypt_stat->num_global_auth_toks--;
		if (auth_tok->global_auth_tok_key
		    && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
			key_put(auth_tok->global_auth_tok_key);
		kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
	}
	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
	memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
}


int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
{
	struct ecryptfs_key_tfm *tmp_key_tfm;

	BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));

	list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
		if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
			if (key_tfm)
				(*key_tfm) = tmp_key_tfm;
			return 1;
		}
	}
	if (key_tfm)
		(*key_tfm) = NULL;
	return 0;
}


static int ecryptfs_decrypt_extent(struct page *page,
				   struct ecryptfs_crypt_stat *crypt_stat,
				   struct page *enc_extent_page,
				   unsigned long extent_offset)
{
	loff_t extent_base;
	char extent_iv[ECRYPTFS_MAX_IV_BYTES];
	int rc;

	extent_base = (((loff_t)page->index)
		       * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
	rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
				(extent_base + extent_offset));
	if (rc) {
		ecryptfs_printk(KERN_ERR, "Error attempting to "
				"derive IV for extent [0x%.16x]; "
				"rc = [%d]\n", (extent_base + extent_offset),
				rc);
		goto out;
	}
	if (unlikely(ecryptfs_verbosity > 0)) {
		ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
				"with iv:\n");
		ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
		ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
				"decryption:\n");
		ecryptfs_dump_hex((char *)
				  (page_address(enc_extent_page)
				   + (extent_offset * crypt_stat->extent_size)),
				  8);
	}
	rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
					  (extent_offset
					   * crypt_stat->extent_size),
					  enc_extent_page, 0,
					  crypt_stat->extent_size, extent_iv);
	if (rc < 0) {
		printk(KERN_ERR "%s: Error attempting to decrypt to page with "
		       "page->index = [%ld], extent_offset = [%ld]; "
		       "rc = [%d]\n", __func__, page->index, extent_offset,
		       rc);
		goto out;
	}
	rc = 0;
	if (unlikely(ecryptfs_verbosity > 0)) {
		ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; "
				"rc = [%d]\n", (extent_base + extent_offset),
				rc);
		ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
				"decryption:\n");
		ecryptfs_dump_hex((char *)(page_address(page)
					   + (extent_offset
					      * crypt_stat->extent_size)), 8);
	}
out:
	return rc;
}


ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
				 char *page_virt, size_t size)
{
	int rc;

	rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
			       size, 0);
	return rc;
}


void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
{
	int x;

	for (x = 0; x < src_size; x++)
		sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
}


u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
{
	int i;
	u8 code = 0;
	struct ecryptfs_cipher_code_str_map_elem *map =
		ecryptfs_cipher_code_str_map;

	if (strcmp(cipher_name, "aes") == 0) {
		switch (key_bytes) {
		case 16:
			code = RFC2440_CIPHER_AES_128;
			break;
		case 24:
			code = RFC2440_CIPHER_AES_192;
			break;
		case 32:
			code = RFC2440_CIPHER_AES_256;
		}
	} else {
		for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
			if (strcmp(cipher_name, map[i].cipher_str) == 0) {
				code = map[i].cipher_code;
				break;
			}
	}
	return code;
}


int ecryptfs_read_and_validate_header_region(char *data,
					     struct inode *ecryptfs_inode)
{
	struct ecryptfs_crypt_stat *crypt_stat =
		&(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
	int rc;

	if (crypt_stat->extent_size == 0)
		crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
	rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
				 ecryptfs_inode);
	if (rc) {
		printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
		       __func__, rc);
		goto out;
	}
	if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
		rc = -EINVAL;
	}
out:
	return rc;
}


static int ecryptfs_read_headers_virt(char *page_virt,
				      struct ecryptfs_crypt_stat *crypt_stat,
				      struct dentry *ecryptfs_dentry,
				      int validate_header_size)
{
	int rc = 0;
	int offset;
	int bytes_read;

	ecryptfs_set_default_sizes(crypt_stat);
	crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
		ecryptfs_dentry->d_sb)->mount_crypt_stat;
	offset = ECRYPTFS_FILE_SIZE_BYTES;
	rc = contains_ecryptfs_marker(page_virt + offset);
	if (rc == 0) {
		rc = -EINVAL;
		goto out;
	}
	offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
	rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
				    &bytes_read);
	if (rc) {
		ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
		goto out;
	}
	if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
		ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
				"file version [%d] is supported by this "
				"version of eCryptfs\n",
				crypt_stat->file_version,
				ECRYPTFS_SUPPORTED_FILE_VERSION);
		rc = -EINVAL;
		goto out;
	}
	offset += bytes_read;
	if (crypt_stat->file_version >= 1) {
		rc = parse_header_metadata(crypt_stat, (page_virt + offset),
					   &bytes_read, validate_header_size);
		if (rc) {
			ecryptfs_printk(KERN_WARNING, "Error reading header "
					"metadata; rc = [%d]\n", rc);
		}
		offset += bytes_read;
	} else
		set_default_header_data(crypt_stat);
	rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
				       ecryptfs_dentry);
out:
	return rc;
}


static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
				       size_t *size,
				       struct ecryptfs_crypt_stat *crypt_stat,
				       struct dentry *ecryptfs_dentry)
{
	int rc;
	size_t written;
	size_t offset;

	offset = ECRYPTFS_FILE_SIZE_BYTES;
	write_ecryptfs_marker((page_virt + offset), &written);
	offset += written;
	write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
	offset += written;
	ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
				       &written);
	offset += written;
	rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
					      ecryptfs_dentry, &written,
					      max - offset);
	if (rc)
		ecryptfs_printk(KERN_WARNING, "Error generating key packet "
				"set; rc = [%d]\n", rc);
	if (size) {
		offset += written;
		*size = offset;
	}
	return rc;
}


static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
{
	crypt_stat->num_header_bytes_at_front =
		ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
}


static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
				  char *page_virt, int *bytes_read)
{
	int rc = 0;
	int i;
	u32 flags;

	flags = get_unaligned_be32(page_virt);
	for (i = 0; i < ((sizeof(ecryptfs_flag_map)
			  / sizeof(struct ecryptfs_flag_map_elem))); i++)
		if (flags & ecryptfs_flag_map[i].file_flag) {
			crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
		} else
			crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
	/* Version is in top 8 bits of the 32-bit flag vector */
	crypt_stat->file_version = ((flags >> 24) & 0xFF);
	(*bytes_read) = 4;
	return rc;
}


int ecryptfs_read_and_validate_xattr_region(char *page_virt,
					    struct dentry *ecryptfs_dentry)
{
	int rc;

	rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
	if (rc)
		goto out;
	if (!contains_ecryptfs_marker(page_virt	+ ECRYPTFS_FILE_SIZE_BYTES)) {
		printk(KERN_WARNING "Valid data found in [%s] xattr, but "
			"the marker is invalid\n", ECRYPTFS_XATTR_NAME);
		rc = -EINVAL;
	}
out:
	return rc;
}


static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
	struct ecryptfs_crypt_stat *crypt_stat,
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
{
	struct ecryptfs_global_auth_tok *global_auth_tok;
	int rc = 0;

	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
	list_for_each_entry(global_auth_tok,
			    &mount_crypt_stat->global_auth_tok_list,
			    mount_crypt_stat_list) {
		if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
			continue;
		rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
		if (rc) {
			printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
			mutex_unlock(
				&mount_crypt_stat->global_auth_tok_list_mutex);
			goto out;
		}
	}
	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
out:
	return rc;
}


write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
		     size_t *written)
{
	u32 flags = 0;
	int i;

	for (i = 0; i < ((sizeof(ecryptfs_flag_map)
			  / sizeof(struct ecryptfs_flag_map_elem))); i++)
		if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
			flags |= ecryptfs_flag_map[i].file_flag;
	/* Version is in top 8 bits of the 32-bit flag vector */
	flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
	put_unaligned_be32(flags, page_virt);
	(*written) = 4;
}


ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
			    char *cipher_name, size_t *key_size)
{
	char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
	char *full_alg_name;
	int rc;

	*key_tfm = NULL;
	if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
		rc = -EINVAL;
		printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
		      "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
		goto out;
	}
	rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
						    "ecb");
	if (rc)
		goto out;
	*key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
	kfree(full_alg_name);
	if (IS_ERR(*key_tfm)) {
		rc = PTR_ERR(*key_tfm);
		printk(KERN_ERR "Unable to allocate crypto cipher with name "
		       "[%s]; rc = [%d]\n", cipher_name, rc);
		goto out;
	}
	crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
	if (*key_size == 0) {
		struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);

		*key_size = alg->max_keysize;
	}
	get_random_bytes(dummy_key, *key_size);
	rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
	if (rc) {
		printk(KERN_ERR "Error attempting to set key of size [%zd] for "
		       "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc);
		rc = -EINVAL;
		goto out;
	}
out:
	return rc;
}


int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
{
	char *full_alg_name;
	int rc = -EINVAL;

	if (!crypt_stat->cipher) {
		ecryptfs_printk(KERN_ERR, "No cipher specified\n");
		goto out;
	}
	ecryptfs_printk(KERN_DEBUG,
			"Initializing cipher [%s]; strlen = [%d]; "
			"key_size_bits = [%d]\n",
			crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
			crypt_stat->key_size << 3);
	if (crypt_stat->tfm) {
		rc = 0;
		goto out;
	}
	mutex_lock(&crypt_stat->cs_tfm_mutex);
	rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
						    crypt_stat->cipher, "cbc");
	if (rc)
		goto out_unlock;
	crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
						 CRYPTO_ALG_ASYNC);
	kfree(full_alg_name);
	if (IS_ERR(crypt_stat->tfm)) {
		rc = PTR_ERR(crypt_stat->tfm);
		ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
				"Error initializing cipher [%s]\n",
				crypt_stat->cipher);
		goto out_unlock;
	}
	crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
	rc = 0;
out_unlock:
	mutex_unlock(&crypt_stat->cs_tfm_mutex);
out:
	return rc;
}


static void ecryptfs_set_default_crypt_stat_vals(
	struct ecryptfs_crypt_stat *crypt_stat,
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
{
	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
						      mount_crypt_stat);
	ecryptfs_set_default_sizes(crypt_stat);
	strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
	crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
	crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
	crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
	crypt_stat->mount_crypt_stat = mount_crypt_stat;
}


ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
{
	memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
	INIT_LIST_HEAD(&crypt_stat->keysig_list);
	mutex_init(&crypt_stat->keysig_list_mutex);
	mutex_init(&crypt_stat->cs_mutex);
	mutex_init(&crypt_stat->cs_tfm_mutex);
	mutex_init(&crypt_stat->cs_hash_tfm_mutex);
	crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
}


int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
{
	int rc = 0;
	int i;

	str[0] = '\0';
	for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
		if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
			strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
	if (str[0] == '\0') {
		ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
				"[%d]\n", cipher_code);
		rc = -EINVAL;
	}
	return rc;
}


ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
			  struct ecryptfs_crypt_stat *crypt_stat,
			  struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
{
	int rc = 0;

	filename->encrypted_filename = NULL;
	filename->encrypted_filename_size = 0;
	if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
	    || (mount_crypt_stat && (mount_crypt_stat->flags
				     & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
		size_t packet_size;
		size_t remaining_bytes;

		rc = ecryptfs_write_tag_70_packet(
			NULL, NULL,
			&filename->encrypted_filename_size,
			mount_crypt_stat, NULL,
			filename->filename_size);
		if (rc) {
			printk(KERN_ERR "%s: Error attempting to get packet "
			       "size for tag 72; rc = [%d]\n", __func__,
			       rc);
			filename->encrypted_filename_size = 0;
			goto out;
		}
		filename->encrypted_filename =
			kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
		if (!filename->encrypted_filename) {
			printk(KERN_ERR "%s: Out of memory whilst attempting "
			       "to kmalloc [%zd] bytes\n", __func__,
			       filename->encrypted_filename_size);
			rc = -ENOMEM;
			goto out;
		}
		remaining_bytes = filename->encrypted_filename_size;
		rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
						  &remaining_bytes,
						  &packet_size,
						  mount_crypt_stat,
						  filename->filename,
						  filename->filename_size);
		if (rc) {
			printk(KERN_ERR "%s: Error attempting to generate "
			       "tag 70 packet; rc = [%d]\n", __func__,
			       rc);
			kfree(filename->encrypted_filename);
			filename->encrypted_filename = NULL;
			filename->encrypted_filename_size = 0;
			goto out;
		}
		filename->encrypted_filename_size = packet_size;
	} else {
		printk(KERN_ERR "%s: No support for requested filename "
		       "encryption method in this release\n", __func__);
		rc = -ENOTSUPP;
		goto out;
	}
out:
	return rc;
}


int ecryptfs_init_crypto(void)
{
	mutex_init(&key_tfm_list_mutex);
	INIT_LIST_HEAD(&key_tfm_list);
	return 0;
}


static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
				  const char *name, size_t name_size)
{
	int rc = 0;

	(*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
	if (!(*copied_name)) {
		rc = -ENOMEM;
		goto out;
	}
	memcpy((void *)(*copied_name), (void *)name, name_size);
	(*copied_name)[(name_size)] = '\0';	/* Only for convenience
						 * in printing out the
						 * string in debug
						 * messages */
	(*copied_name_size) = name_size;
out:
	return rc;
}


static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
						  char *cipher_name,
						  char *chaining_modifier)
{
	int cipher_name_len = strlen(cipher_name);
	int chaining_modifier_len = strlen(chaining_modifier);
	int algified_name_len;
	int rc;

	algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
	(*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
	if (!(*algified_name)) {
		rc = -ENOMEM;
		goto out;
	}
	snprintf((*algified_name), algified_name_len, "%s(%s)",
		 chaining_modifier, cipher_name);
	rc = 0;
out:
	return rc;
}


int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
{
	struct ecryptfs_crypt_stat *crypt_stat =
	    &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
	    &ecryptfs_superblock_to_private(
		    ecryptfs_dentry->d_sb)->mount_crypt_stat;
	int cipher_name_len;
	int rc = 0;

	ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
	crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
						      mount_crypt_stat);
	rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
							 mount_crypt_stat);
	if (rc) {
		printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
		       "to the inode key sigs; rc = [%d]\n", rc);
		goto out;
	}
	cipher_name_len =
		strlen(mount_crypt_stat->global_default_cipher_name);
	memcpy(crypt_stat->cipher,
	       mount_crypt_stat->global_default_cipher_name,
	       cipher_name_len);
	crypt_stat->cipher[cipher_name_len] = '\0';
	crypt_stat->key_size =
		mount_crypt_stat->global_default_cipher_key_size;
	ecryptfs_generate_new_key(crypt_stat);
	rc = ecryptfs_init_crypt_ctx(crypt_stat);
	if (rc)
		ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
				"context for cipher [%s]: rc = [%d]\n",
				crypt_stat->cipher, rc);
out:
	return rc;
}


void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
{
	/* Default values; may be overwritten as we are parsing the
	 * packets. */
	crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
	set_extent_mask_and_shift(crypt_stat);
	crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
		crypt_stat->num_header_bytes_at_front = 0;
	else {
		if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
			crypt_stat->num_header_bytes_at_front =
				ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
		else
			crypt_stat->num_header_bytes_at_front =	PAGE_CACHE_SIZE;
	}
}


int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
		       loff_t offset)
{
	int rc = 0;
	char dst[MD5_DIGEST_SIZE];
	char src[ECRYPTFS_MAX_IV_BYTES + 16];

	if (unlikely(ecryptfs_verbosity > 0)) {
		ecryptfs_printk(KERN_DEBUG, "root iv:\n");
		ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
	}
	/* TODO: It is probably secure to just cast the least
	 * significant bits of the root IV into an unsigned long and
	 * add the offset to that rather than go through all this
	 * hashing business. -Halcrow */
	memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
	memset((src + crypt_stat->iv_bytes), 0, 16);
	snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
	if (unlikely(ecryptfs_verbosity > 0)) {
		ecryptfs_printk(KERN_DEBUG, "source:\n");
		ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
	}
	rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
				    (crypt_stat->iv_bytes + 16));
	if (rc) {
		ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
				"MD5 while generating IV for a page\n");
		goto out;
	}
	memcpy(iv, dst, crypt_stat->iv_bytes);
	if (unlikely(ecryptfs_verbosity > 0)) {
		ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
		ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
	}
out:
	return rc;
}


static void write_ecryptfs_marker(char *page_virt, size_t *written)
{
	u32 m_1, m_2;

	get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
	m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
	put_unaligned_be32(m_1, page_virt);
	page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
	put_unaligned_be32(m_2, page_virt);
	(*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
}


ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
			     struct page *dst_page, int dst_offset,
			     struct page *src_page, int src_offset, int size,
			     unsigned char *iv)
{
	struct scatterlist src_sg, dst_sg;

	sg_init_table(&src_sg, 1);
	sg_set_page(&src_sg, src_page, size, src_offset);

	sg_init_table(&dst_sg, 1);
	sg_set_page(&dst_sg, dst_page, size, dst_offset);

	return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
}


int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
{
	int rc = 0;
	char *page_virt = NULL;
	struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
	struct ecryptfs_crypt_stat *crypt_stat =
	    &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
		&ecryptfs_superblock_to_private(
			ecryptfs_dentry->d_sb)->mount_crypt_stat;

	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
						      mount_crypt_stat);
	/* Read the first page from the underlying file */
	page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
	if (!page_virt) {
		rc = -ENOMEM;
		printk(KERN_ERR "%s: Unable to allocate page_virt\n",
		       __func__);
		goto out;
	}
	rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
				 ecryptfs_inode);
	if (!rc)
		rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
						ecryptfs_dentry,
						ECRYPTFS_VALIDATE_HEADER_SIZE);
	if (rc) {
		rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
		if (rc) {
			printk(KERN_DEBUG "Valid eCryptfs headers not found in "
			       "file header region or xattr region\n");
			rc = -EINVAL;
			goto out;
		}
		rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
						ecryptfs_dentry,
						ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
		if (rc) {
			printk(KERN_DEBUG "Valid eCryptfs headers not found in "
			       "file xattr region either\n");
			rc = -EINVAL;
		}
		if (crypt_stat->mount_crypt_stat->flags
		    & ECRYPTFS_XATTR_METADATA_ENABLED) {
			crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
		} else {
			printk(KERN_WARNING "Attempt to access file with "
			       "crypto metadata only in the extended attribute "
			       "region, but eCryptfs was mounted without "
			       "xattr support enabled. eCryptfs will not treat "
			       "this like an encrypted file.\n");
			rc = -EINVAL;
		}
	}
out:
	if (page_virt) {
		memset(page_virt, 0, PAGE_CACHE_SIZE);
		kmem_cache_free(ecryptfs_header_cache_1, page_virt);
	}
	return rc;
}


void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
				  unsigned char *src, size_t src_size)
{
	size_t num_blocks;
	size_t block_num = 0;
	size_t dst_offset = 0;
	unsigned char last_block[3];

	if (src_size == 0) {
		(*dst_size) = 0;
		goto out;
	}
	num_blocks = (src_size / 3);
	if ((src_size % 3) == 0) {
		memcpy(last_block, (&src[src_size - 3]), 3);
	} else {
		num_blocks++;
		last_block[2] = 0x00;
		switch (src_size % 3) {
		case 1:
			last_block[0] = src[src_size - 1];
			last_block[1] = 0x00;
			break;
		case 2:
			last_block[0] = src[src_size - 2];
			last_block[1] = src[src_size - 1];
		}
	}
	(*dst_size) = (num_blocks * 4);
	if (!dst)
		goto out;
	while (block_num < num_blocks) {
		unsigned char *src_block;
		unsigned char dst_block[4];

		if (block_num == (num_blocks - 1))
			src_block = last_block;
		else
			src_block = &src[block_num * 3];
		dst_block[0] = ((src_block[0] >> 2) & 0x3F);
		dst_block[1] = (((src_block[0] << 4) & 0x30)
				| ((src_block[1] >> 4) & 0x0F));
		dst_block[2] = (((src_block[1] << 2) & 0x3C)
				| ((src_block[2] >> 6) & 0x03));
		dst_block[3] = (src_block[2] & 0x3F);
		dst[dst_offset++] = portable_filename_chars[dst_block[0]];
		dst[dst_offset++] = portable_filename_chars[dst_block[1]];
		dst[dst_offset++] = portable_filename_chars[dst_block[2]];
		dst[dst_offset++] = portable_filename_chars[dst_block[3]];
		block_num++;
	}
out:
	return;
}


ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
			     struct page *dst_page, int dst_offset,
			     struct page *src_page, int src_offset, int size,
			     unsigned char *iv)
{
	struct scatterlist src_sg, dst_sg;

	sg_init_table(&src_sg, 1);
	sg_init_table(&dst_sg, 1);

	sg_set_page(&src_sg, src_page, size, src_offset);
	sg_set_page(&dst_sg, dst_page, size, dst_offset);
	return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
}


static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
	struct ecryptfs_crypt_stat *crypt_stat,
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
{
	if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
		crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
		crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
	if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
		crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
		if (mount_crypt_stat->flags
		    & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
			crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
		else if (mount_crypt_stat->flags
			 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
			crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
	}
}


int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
{
	int rc = 0;
	char dst[MD5_DIGEST_SIZE];

	BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
	BUG_ON(crypt_stat->iv_bytes <= 0);
	if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
		rc = -EINVAL;
		ecryptfs_printk(KERN_WARNING, "Session key not valid; "
				"cannot generate root IV\n");
		goto out;
	}
	rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
				    crypt_stat->key_size);
	if (rc) {
		ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
				"MD5 while generating root IV\n");
		goto out;
	}
	memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
out:
	if (rc) {
		memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
		crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
	}
	return rc;
}


ecryptfs_write_header_metadata(char *virt,
			       struct ecryptfs_crypt_stat *crypt_stat,
			       size_t *written)
{
	u32 header_extent_size;
	u16 num_header_extents_at_front;

	header_extent_size = (u32)crypt_stat->extent_size;
	num_header_extents_at_front =
		(u16)(crypt_stat->num_header_bytes_at_front
		      / crypt_stat->extent_size);
	put_unaligned_be32(header_extent_size, virt);
	virt += 4;
	put_unaligned_be16(num_header_extents_at_front, virt);
	(*written) = 6;
}


int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
					       struct mutex **tfm_mutex,
					       char *cipher_name)
{
	struct ecryptfs_key_tfm *key_tfm;
	int rc = 0;

	(*tfm) = NULL;
	(*tfm_mutex) = NULL;

	mutex_lock(&key_tfm_list_mutex);
	if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
		rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
		if (rc) {
			printk(KERN_ERR "Error adding new key_tfm to list; "
					"rc = [%d]\n", rc);
			goto out;
		}
	}
	(*tfm) = key_tfm->key_tfm;
	(*tfm_mutex) = &key_tfm->key_tfm_mutex;
out:
	mutex_unlock(&key_tfm_list_mutex);
	return rc;
}


ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
			      const unsigned char *src, size_t src_size)
{
	u8 current_bit_offset = 0;
	size_t src_byte_offset = 0;
	size_t dst_byte_offset = 0;

	if (dst == NULL) {
		/* Not exact; conservatively long. Every block of 4
		 * encoded characters decodes into a block of 3
		 * decoded characters. This segment of code provides
		 * the caller with the maximum amount of allocated
		 * space that @dst will need to point to in a
		 * subsequent call. */
		(*dst_size) = (((src_size + 1) * 3) / 4);
		goto out;
	}
	while (src_byte_offset < src_size) {
		unsigned char src_byte =
				filename_rev_map[(int)src[src_byte_offset]];

		switch (current_bit_offset) {
		case 0:
			dst[dst_byte_offset] = (src_byte << 2);
			current_bit_offset = 6;
			break;
		case 6:
			dst[dst_byte_offset++] |= (src_byte >> 4);
			dst[dst_byte_offset] = ((src_byte & 0xF)
						 << 4);
			current_bit_offset = 4;
			break;
		case 4:
			dst[dst_byte_offset++] |= (src_byte >> 2);
			dst[dst_byte_offset] = (src_byte << 6);
			current_bit_offset = 2;
			break;
		case 2:
			dst[dst_byte_offset++] |= (src_byte);
			dst[dst_byte_offset] = 0;
			current_bit_offset = 0;
			break;
		}
		src_byte_offset++;
	}
	(*dst_size) = dst_byte_offset;
out:
	return;
}


int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
			int sg_size)
{
	int i = 0;
	struct page *pg;
	int offset;
	int remainder_of_page;

	sg_init_table(sg, sg_size);

	while (size > 0 && i < sg_size) {
		pg = virt_to_page(addr);
		offset = offset_in_page(addr);
		if (sg)
			sg_set_page(&sg[i], pg, 0, offset);
		remainder_of_page = PAGE_CACHE_SIZE - offset;
		if (size >= remainder_of_page) {
			if (sg)
				sg[i].length = remainder_of_page;
			addr += remainder_of_page;
			size -= remainder_of_page;
		} else {
			if (sg)
				sg[i].length = size;
			addr += size;
			size = 0;
		}
		i++;
	}
	if (size > 0)
		return -ENOMEM;
	return i;
}


static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
			       struct scatterlist *dest_sg,
			       struct scatterlist *src_sg, int size,
			       unsigned char *iv)
{
	struct blkcipher_desc desc = {
		.tfm = crypt_stat->tfm,
		.info = iv,
		.flags = CRYPTO_TFM_REQ_MAY_SLEEP
	};
	int rc = 0;

	BUG_ON(!crypt_stat || !crypt_stat->tfm
	       || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
	if (unlikely(ecryptfs_verbosity > 0)) {
		ecryptfs_printk(KERN_DEBUG, "Key size [%d]; key:\n",
				crypt_stat->key_size);
		ecryptfs_dump_hex(crypt_stat->key,
				  crypt_stat->key_size);
	}
	/* Consider doing this once, when the file is opened */
	mutex_lock(&crypt_stat->cs_tfm_mutex);
	if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
		rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
					     crypt_stat->key_size);
		crypt_stat->flags |= ECRYPTFS_KEY_SET;
	}
	if (rc) {
		ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
				rc);
		mutex_unlock(&crypt_stat->cs_tfm_mutex);
		rc = -EINVAL;
		goto out;
	}
	ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
	crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
	mutex_unlock(&crypt_stat->cs_tfm_mutex);
out:
	return rc;
}


static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
					       unsigned int order)
{
	struct page *page;

	page = alloc_pages(gfp_mask | __GFP_ZERO, order);
	if (page)
		return (unsigned long) page_address(page);
	return 0;
}


ecryptfs_write_metadata_to_contents(struct dentry *ecryptfs_dentry,
				    char *virt, size_t virt_len)
{
	int rc;

	rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
				  0, virt_len);
	if (rc)
		printk(KERN_ERR "%s: Error attempting to write header "
		       "information to lower file; rc = [%d]\n", __func__,
		       rc);
	return rc;
}


int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
					 size_t *plaintext_name_size,
					 struct dentry *ecryptfs_dir_dentry,
					 const char *name, size_t name_size)
{
	char *decoded_name;
	size_t decoded_name_size;
	size_t packet_size;
	int rc = 0;

	if ((name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
	    && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
			ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
		struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
			&ecryptfs_superblock_to_private(
				ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
		const char *orig_name = name;
		size_t orig_name_size = name_size;

		name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
		name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
		ecryptfs_decode_from_filename(NULL, &decoded_name_size,
					      name, name_size);
		decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
		if (!decoded_name) {
			printk(KERN_ERR "%s: Out of memory whilst attempting "
			       "to kmalloc [%zd] bytes\n", __func__,
			       decoded_name_size);
			rc = -ENOMEM;
			goto out;
		}
		ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
					      name, name_size);
		rc = ecryptfs_parse_tag_70_packet(plaintext_name,
						  plaintext_name_size,
						  &packet_size,
						  mount_crypt_stat,
						  decoded_name,
						  decoded_name_size);
		if (rc) {
			printk(KERN_INFO "%s: Could not parse tag 70 packet "
			       "from filename; copying through filename "
			       "as-is\n", __func__);
			rc = ecryptfs_copy_filename(plaintext_name,
						    plaintext_name_size,
						    orig_name, orig_name_size);
			goto out_free;
		}
	} else {
		rc = ecryptfs_copy_filename(plaintext_name,
					    plaintext_name_size,
					    name, name_size);
		goto out;
	}
out_free:
	kfree(decoded_name);
out:
	return rc;
}


void ecryptfs_from_hex(char *dst, char *src, int dst_size)
{
	int x;
	char tmp[3] = { 0, };

	for (x = 0; x < dst_size; x++) {
		tmp[0] = src[x * 2];
		tmp[1] = src[x * 2 + 1];
		dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
	}
}


static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
			       struct scatterlist *dest_sg,
			       struct scatterlist *src_sg, int size,
			       unsigned char *iv)
{
	struct blkcipher_desc desc = {
		.tfm = crypt_stat->tfm,
		.info = iv,
		.flags = CRYPTO_TFM_REQ_MAY_SLEEP
	};
	int rc = 0;

	/* Consider doing this once, when the file is opened */
	mutex_lock(&crypt_stat->cs_tfm_mutex);
	rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
				     crypt_stat->key_size);
	if (rc) {
		ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
				rc);
		mutex_unlock(&crypt_stat->cs_tfm_mutex);
		rc = -EINVAL;
		goto out;
	}
	ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
	rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
	mutex_unlock(&crypt_stat->cs_tfm_mutex);
	if (rc) {
		ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
				rc);
		goto out;
	}
	rc = size;
out:
	return rc;
}


static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
					     struct ecryptfs_crypt_stat *crypt_stat)
{
	(*offset) = (crypt_stat->num_header_bytes_at_front
		     + (crypt_stat->extent_size * extent_num));
}


static int ecryptfs_calculate_md5(char *dst,
				  struct ecryptfs_crypt_stat *crypt_stat,
				  char *src, int len)
{
	struct scatterlist sg;
	struct hash_desc desc = {
		.tfm = crypt_stat->hash_tfm,
		.flags = CRYPTO_TFM_REQ_MAY_SLEEP
	};
	int rc = 0;

	mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
	sg_init_one(&sg, (u8 *)src, len);
	if (!desc.tfm) {
		desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
					     CRYPTO_ALG_ASYNC);
		if (IS_ERR(desc.tfm)) {
			rc = PTR_ERR(desc.tfm);
			ecryptfs_printk(KERN_ERR, "Error attempting to "
					"allocate crypto context; rc = [%d]\n",
					rc);
			goto out;
		}
		crypt_stat->hash_tfm = desc.tfm;
	}
	rc = crypto_hash_init(&desc);
	if (rc) {
		printk(KERN_ERR
		       "%s: Error initializing crypto hash; rc = [%d]\n",
		       __func__, rc);
		goto out;
	}
	rc = crypto_hash_update(&desc, &sg, len);
	if (rc) {
		printk(KERN_ERR
		       "%s: Error updating crypto hash; rc = [%d]\n",
		       __func__, rc);
		goto out;
	}
	rc = crypto_hash_final(&desc, dst);
	if (rc) {
		printk(KERN_ERR
		       "%s: Error finalizing crypto hash; rc = [%d]\n",
		       __func__, rc);
		goto out;
	}
out:
	mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
	return rc;
}


int ecryptfs_destroy_crypto(void)
{
	struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;

	mutex_lock(&key_tfm_list_mutex);
	list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
				 key_tfm_list) {
		list_del(&key_tfm->key_tfm_list);
		if (key_tfm->key_tfm)
			crypto_free_blkcipher(key_tfm->key_tfm);
		kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
	}
	mutex_unlock(&key_tfm_list_mutex);
	return 0;
}


static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
				 char *virt, int *bytes_read,
				 int validate_header_size)
{
	int rc = 0;
	u32 header_extent_size;
	u16 num_header_extents_at_front;

	header_extent_size = get_unaligned_be32(virt);
	virt += sizeof(__be32);
	num_header_extents_at_front = get_unaligned_be16(virt);
	crypt_stat->num_header_bytes_at_front =
		(((size_t)num_header_extents_at_front
		  * (size_t)header_extent_size));
	(*bytes_read) = (sizeof(__be32) + sizeof(__be16));
	if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
	    && (crypt_stat->num_header_bytes_at_front
		< ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
		rc = -EINVAL;
		printk(KERN_WARNING "Invalid header size: [%zd]\n",
		       crypt_stat->num_header_bytes_at_front);
	}
	return rc;
}


static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
				   struct ecryptfs_crypt_stat *crypt_stat,
				   struct page *page,
				   unsigned long extent_offset)
{
	loff_t extent_base;
	char extent_iv[ECRYPTFS_MAX_IV_BYTES];
	int rc;

	extent_base = (((loff_t)page->index)
		       * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
	rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
				(extent_base + extent_offset));
	if (rc) {
		ecryptfs_printk(KERN_ERR, "Error attempting to "
				"derive IV for extent [0x%.16x]; "
				"rc = [%d]\n", (extent_base + extent_offset),
				rc);
		goto out;
	}
	if (unlikely(ecryptfs_verbosity > 0)) {
		ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
				"with iv:\n");
		ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
		ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
				"encryption:\n");
		ecryptfs_dump_hex((char *)
				  (page_address(page)
				   + (extent_offset * crypt_stat->extent_size)),
				  8);
	}
	rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
					  page, (extent_offset
						 * crypt_stat->extent_size),
					  crypt_stat->extent_size, extent_iv);
	if (rc < 0) {
		printk(KERN_ERR "%s: Error attempting to encrypt page with "
		       "page->index = [%ld], extent_offset = [%ld]; "
		       "rc = [%d]\n", __func__, page->index, extent_offset,
		       rc);
		goto out;
	}
	rc = 0;
	if (unlikely(ecryptfs_verbosity > 0)) {
		ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
				"rc = [%d]\n", (extent_base + extent_offset),
				rc);
		ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
				"encryption:\n");
		ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
	}
out:
	return rc;
}


static int contains_ecryptfs_marker(char *data)
{
	u32 m_1, m_2;

	m_1 = get_unaligned_be32(data);
	m_2 = get_unaligned_be32(data + 4);
	if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
		return 1;
	ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
			"MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
			MAGIC_ECRYPTFS_MARKER);
	ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
			"[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
	return 0;
}


static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
{
	int extent_size_tmp;

	crypt_stat->extent_mask = 0xFFFFFFFF;
	crypt_stat->extent_shift = 0;
	if (crypt_stat->extent_size == 0)
		return;
	extent_size_tmp = crypt_stat->extent_size;
	while ((extent_size_tmp & 0x01) == 0) {
		extent_size_tmp >>= 1;
		crypt_stat->extent_mask <<= 1;
		crypt_stat->extent_shift++;
	}
}


static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
{
	get_random_bytes(crypt_stat->key, crypt_stat->key_size);
	crypt_stat->flags |= ECRYPTFS_KEY_VALID;
	ecryptfs_compute_root_iv(crypt_stat);
	if (unlikely(ecryptfs_verbosity > 0)) {
		ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
		ecryptfs_dump_hex(crypt_stat->key,
				  crypt_stat->key_size);
	}
}


int ecryptfs_encrypt_and_encode_filename(
	char **encoded_name,
	size_t *encoded_name_size,
	struct ecryptfs_crypt_stat *crypt_stat,
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
	const char *name, size_t name_size)
{
	size_t encoded_name_no_prefix_size;
	int rc = 0;

	(*encoded_name) = NULL;
	(*encoded_name_size) = 0;
	if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
	    || (mount_crypt_stat && (mount_crypt_stat->flags
				     & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
		struct ecryptfs_filename *filename;

		filename = kzalloc(sizeof(*filename), GFP_KERNEL);
		if (!filename) {
			printk(KERN_ERR "%s: Out of memory whilst attempting "
			       "to kzalloc [%zd] bytes\n", __func__,
			       sizeof(*filename));
			rc = -ENOMEM;
			goto out;
		}
		filename->filename = (char *)name;
		filename->filename_size = name_size;
		rc = ecryptfs_encrypt_filename(filename, crypt_stat,
					       mount_crypt_stat);
		if (rc) {
			printk(KERN_ERR "%s: Error attempting to encrypt "
			       "filename; rc = [%d]\n", __func__, rc);
			kfree(filename);
			goto out;
		}
		ecryptfs_encode_for_filename(
			NULL, &encoded_name_no_prefix_size,
			filename->encrypted_filename,
			filename->encrypted_filename_size);
		if ((crypt_stat && (crypt_stat->flags
				    & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
		    || (mount_crypt_stat
			&& (mount_crypt_stat->flags
			    & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
			(*encoded_name_size) =
				(ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
				 + encoded_name_no_prefix_size);
		else
			(*encoded_name_size) =
				(ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
				 + encoded_name_no_prefix_size);
		(*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
		if (!(*encoded_name)) {
			printk(KERN_ERR "%s: Out of memory whilst attempting "
			       "to kzalloc [%zd] bytes\n", __func__,
			       (*encoded_name_size));
			rc = -ENOMEM;
			kfree(filename->encrypted_filename);
			kfree(filename);
			goto out;
		}
		if ((crypt_stat && (crypt_stat->flags
				    & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
		    || (mount_crypt_stat
			&& (mount_crypt_stat->flags
			    & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
			memcpy((*encoded_name),
			       ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
			       ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
			ecryptfs_encode_for_filename(
			    ((*encoded_name)
			     + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
			    &encoded_name_no_prefix_size,
			    filename->encrypted_filename,
			    filename->encrypted_filename_size);
			(*encoded_name_size) =
				(ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
				 + encoded_name_no_prefix_size);
			(*encoded_name)[(*encoded_name_size)] = '\0';
			(*encoded_name_size)++;
		} else {
			rc = -ENOTSUPP;
		}
		if (rc) {
			printk(KERN_ERR "%s: Error attempting to encode "
			       "encrypted filename; rc = [%d]\n", __func__,
			       rc);
			kfree((*encoded_name));
			(*encoded_name) = NULL;
			(*encoded_name_size) = 0;
		}
		kfree(filename->encrypted_filename);
		kfree(filename);
	} else {
		rc = ecryptfs_copy_filename(encoded_name,
					    encoded_name_size,
					    name, name_size);
	}
out:
	return rc;
}


int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
{
	struct dentry *lower_dentry =
		ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
	ssize_t size;
	int rc = 0;

	size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
				       page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
	if (size < 0) {
		if (unlikely(ecryptfs_verbosity > 0))
			printk(KERN_INFO "Error attempting to read the [%s] "
			       "xattr from the lower file; return value = "
			       "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
		rc = -EINVAL;
		goto out;
	}
out:
	return rc;
}


void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
{
	struct ecryptfs_key_sig *key_sig, *key_sig_tmp;

	if (crypt_stat->tfm)
		crypto_free_blkcipher(crypt_stat->tfm);
	if (crypt_stat->hash_tfm)
		crypto_free_hash(crypt_stat->hash_tfm);
	mutex_lock(&crypt_stat->keysig_list_mutex);
	list_for_each_entry_safe(key_sig, key_sig_tmp,
				 &crypt_stat->keysig_list, crypt_stat_list) {
		list_del(&key_sig->crypt_stat_list);
		kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
	}
	mutex_unlock(&crypt_stat->keysig_list_mutex);
	memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
}


int ecryptfs_encrypt_page(struct page *page)
{
	struct inode *ecryptfs_inode;
	struct ecryptfs_crypt_stat *crypt_stat;
	char *enc_extent_virt;
	struct page *enc_extent_page = NULL;
	loff_t extent_offset;
	int rc = 0;

	ecryptfs_inode = page->mapping->host;
	crypt_stat =
		&(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
	if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
		rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page,
						       0, PAGE_CACHE_SIZE);
		if (rc)
			printk(KERN_ERR "%s: Error attempting to copy "
			       "page at index [%ld]\n", __func__,
			       page->index);
		goto out;
	}
	enc_extent_page = alloc_page(GFP_USER);
	if (!enc_extent_page) {
		rc = -ENOMEM;
		ecryptfs_printk(KERN_ERR, "Error allocating memory for "
				"encrypted extent\n");
		goto out;
	}
	enc_extent_virt = kmap(enc_extent_page);
	for (extent_offset = 0;
	     extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
	     extent_offset++) {
		loff_t offset;

		rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
					     extent_offset);
		if (rc) {
			printk(KERN_ERR "%s: Error encrypting extent; "
			       "rc = [%d]\n", __func__, rc);
			goto out;
		}
		ecryptfs_lower_offset_for_extent(
			&offset, ((((loff_t)page->index)
				   * (PAGE_CACHE_SIZE
				      / crypt_stat->extent_size))
				  + extent_offset), crypt_stat);
		rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
					  offset, crypt_stat->extent_size);
		if (rc) {
			ecryptfs_printk(KERN_ERR, "Error attempting "
					"to write lower page; rc = [%d]"
					"\n", rc);
			goto out;
		}
	}
out:
	if (enc_extent_page) {
		kunmap(enc_extent_page);
		__free_page(enc_extent_page);
	}
	return rc;
}


ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
			 size_t key_size)
{
	struct ecryptfs_key_tfm *tmp_tfm;
	int rc = 0;

	BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));

	tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
	if (key_tfm != NULL)
		(*key_tfm) = tmp_tfm;
	if (!tmp_tfm) {
		rc = -ENOMEM;
		printk(KERN_ERR "Error attempting to allocate from "
		       "ecryptfs_key_tfm_cache\n");
		goto out;
	}
	mutex_init(&tmp_tfm->key_tfm_mutex);
	strncpy(tmp_tfm->cipher_name, cipher_name,
		ECRYPTFS_MAX_CIPHER_NAME_SIZE);
	tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
	tmp_tfm->key_size = key_size;
	rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
					 tmp_tfm->cipher_name,
					 &tmp_tfm->key_size);
	if (rc) {
		printk(KERN_ERR "Error attempting to initialize key TFM "
		       "cipher with name = [%s]; rc = [%d]\n",
		       tmp_tfm->cipher_name, rc);
		kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
		if (key_tfm != NULL)
			(*key_tfm) = NULL;
		goto out;
	}
	list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
out:
	return rc;
}


static int utf8_encoded_expected_len(const char *str)
{
	unsigned char c = (unsigned char)str[0];

	if (c < 0x80)
		return 1;
	if ((c & 0xe0) == 0xc0)
		return 2;
	if ((c & 0xf0) == 0xe0)
		return 3;
	if ((c & 0xf8) == 0xf0)
		return 4;
	if ((c & 0xfc) == 0xf8)
		return 5;
	if ((c & 0xfe) == 0xfc)
		return 6;
	return 0;
}

path_encode: fix max length calculation

Sebastian Krahmer wrote:
> it should reserve 4 times not 3 times len :)


static int utf8_encoded_valid_unichar(const char *str)
{
	int len;
	int unichar;
	int i;

	len = utf8_encoded_expected_len(str);
	if (len == 0)
		return -1;

	/* ascii is valid */
	if (len == 1)
		return 1;

	/* check if expected encoded chars are available */
	for (i = 0; i < len; i++)
		if ((str[i] & 0x80) != 0x80)
			return -1;

	unichar = utf8_encoded_to_unichar(str);

	/* check if encoded length matches encoded value */
	if (utf8_unichar_to_encoded_len(unichar) != len)
		return -1;

	/* check if value has valid range */
	if (!utf8_unichar_valid_range(unichar))
		return -1;

	return len;
}


size_t util_strlcpy(char *dst, const char *src, size_t size)
{
	size_t bytes = 0;
	char *q = dst;
	const char *p = src;
	char ch;

	while ((ch = *p++)) {
		if (bytes+1 < size)
			*q++ = ch;
		bytes++;
	}

	/* If size == 0 there is no space for a final null... */
	if (size)
		*q = '\0';
	return bytes;
}


int udev_util_encode_string(const char *str, char *str_enc, size_t len)
{
	size_t i, j;

	if (str == NULL || str_enc == NULL || len == 0)
		return -1;

	str_enc[0] = '\0';
	for (i = 0, j = 0; str[i] != '\0'; i++) {
		int seqlen;

		seqlen = utf8_encoded_valid_unichar(&str[i]);
		if (seqlen > 1) {
			memcpy(&str_enc[j], &str[i], seqlen);
			j += seqlen;
			i += (seqlen-1);
		} else if (str[i] == '\\' || !is_whitelisted(str[i], NULL)) {
			sprintf(&str_enc[j], "\\x%02x", (unsigned char) str[i]);
			j += 4;
		} else {
			str_enc[j] = str[i];
			j++;
		}
		if (j+3 >= len)
			goto err;
	}
	str_enc[j] = '\0';
	return 0;
err:
	return -1;
}


int udev_util_replace_chars(char *str, const char *white)
{
	size_t i = 0;
	int replaced = 0;

	while (str[i] != '\0') {
		int len;

		if (is_whitelisted(str[i], white)) {
			i++;
			continue;
		}

		/* accept hex encoding */
		if (str[i] == '\\' && str[i+1] == 'x') {
			i += 2;
			continue;
		}

		/* accept valid utf8 */
		len = utf8_encoded_valid_unichar(&str[i]);
		if (len > 1) {
			i += len;
			continue;
		}

		/* if space is allowed, replace whitespace with ordinary space */
		if (isspace(str[i]) && white != NULL && strchr(white, ' ') != NULL) {
			str[i] = ' ';
			i++;
			replaced++;
			continue;
		}

		/* everything else is replaced with '_' */
		str[i] = '_';
		i++;
		replaced++;
	}
	return replaced;
}


size_t util_strlcat(char *dst, const char *src, size_t size)
{
	size_t bytes = 0;
	char *q = dst;
	const char *p = src;
	char ch;

	while (bytes < size && *q) {
		q++;
		bytes++;
	}
	if (bytes == size)
		return (bytes + strlen(src));

	while ((ch = *p++)) {
		if (bytes+1 < size)
		*q++ = ch;
		bytes++;
	}

	*q = '\0';
	return bytes;
}


ssize_t util_get_sys_driver(struct udev *udev, const char *syspath, char *driver, size_t size)
{
	return get_sys_link(udev, "driver", syspath, driver, size);
}


int util_log_priority(const char *priority)
{
	char *endptr;
	int prio;

	prio = strtol(priority, &endptr, 10);
	if (endptr[0] == '\0')
		return prio;
	if (strncasecmp(priority, "err", 3) == 0)
		return LOG_ERR;
	if (strcasecmp(priority, "info") == 0)
		return LOG_INFO;
	if (strcasecmp(priority, "debug") == 0)
		return LOG_DEBUG;
	return 0;
}


static ssize_t get_sys_link(struct udev *udev, const char *slink, const char *syspath, char *value, size_t size)
{
	char path[UTIL_PATH_SIZE];
	ssize_t len;
	const char *pos;

	util_strlcpy(path, syspath, sizeof(path));
	util_strlcat(path, "/", sizeof(path));
	util_strlcat(path, slink, sizeof(path));
	len = readlink(path, path, sizeof(path));
	if (len < 0 || len >= (ssize_t) sizeof(path))
		return -1;
	path[len] = '\0';
	pos = strrchr(path, '/');
	if (pos == NULL)
		return -1;
	pos = &pos[1];
	dbg(udev, "resolved link to: '%s'\n", pos);
	return util_strlcpy(value, pos, size);
}


static int utf8_encoded_to_unichar(const char *str)
{
	int unichar;
	int len;
	int i;

	len = utf8_encoded_expected_len(str);
	switch (len) {
	case 1:
		return (int)str[0];
	case 2:
		unichar = str[0] & 0x1f;
		break;
	case 3:
		unichar = (int)str[0] & 0x0f;
		break;
	case 4:
		unichar = (int)str[0] & 0x07;
		break;
	case 5:
		unichar = (int)str[0] & 0x03;
		break;
	case 6:
		unichar = (int)str[0] & 0x01;
		break;
	default:
		return -1;
	}

	for (i = 1; i < len; i++) {
		if (((int)str[i] & 0xc0) != 0x80)
			return -1;
		unichar <<= 6;
		unichar |= (int)str[i] & 0x3f;
	}

	return unichar;
}


void util_set_fd_cloexec(int fd)
{
	int flags;

	flags = fcntl(fd, F_GETFD);
	if (flags < 0)
		flags = FD_CLOEXEC;
	else
		flags |= FD_CLOEXEC;
	fcntl(fd, F_SETFD, flags);
}


ssize_t util_get_sys_subsystem(struct udev *udev, const char *syspath, char *subsystem, size_t size)
{
	return get_sys_link(udev, "subsystem", syspath, subsystem, size);
}


static int utf8_unichar_to_encoded_len(int unichar)
{
	if (unichar < 0x80)
		return 1;
	if (unichar < 0x800)
		return 2;
	if (unichar < 0x10000)
		return 3;
	if (unichar < 0x200000)
		return 4;
	if (unichar < 0x4000000)
		return 5;
	return 6;
}


int udev_util_replace_whitespace(const char *str, char *to, size_t len)
{
	size_t i, j;

	/* strip trailing whitespace */
	len = strnlen(str, len);
	while (len && isspace(str[len-1]))
		len--;

	/* strip leading whitespace */
	i = 0;
	while (isspace(str[i]) && (i < len))
		i++;

	j = 0;
	while (i < len) {
		/* substitute multiple whitespace with a single '_' */
		if (isspace(str[i])) {
			while (isspace(str[i]))
				i++;
			to[j++] = '_';
		}
		to[j++] = str[i++];
	}
	to[j] = '\0';
	return 0;
}


int util_resolve_sys_link(struct udev *udev, char *syspath, size_t size)
{
	char link_target[UTIL_PATH_SIZE];

	int len;
	int i;
	int back;

	len = readlink(syspath, link_target, sizeof(link_target));
	if (len <= 0)
		return -1;
	link_target[len] = '\0';
	dbg(udev, "path link '%s' points to '%s'\n", syspath, link_target);

	for (back = 0; strncmp(&link_target[back * 3], "../", 3) == 0; back++)
		;
	dbg(udev, "base '%s', tail '%s', back %i\n", syspath, &link_target[back * 3], back);
	for (i = 0; i <= back; i++) {
		char *pos = strrchr(syspath, '/');

		if (pos == NULL)
			return -1;
		pos[0] = '\0';
	}
	dbg(udev, "after moving back '%s'\n", syspath);
	util_strlcat(syspath, "/", size);
	util_strlcat(syspath, &link_target[back * 3], size);
	return 0;
}


static int utf8_unichar_valid_range(int unichar)
{
	if (unichar > 0x10ffff)
		return 0;
	if ((unichar & 0xfffff800) == 0xd800)
		return 0;
	if ((unichar > 0xfdcf) && (unichar < 0xfdf0))
		return 0;
	if ((unichar & 0xffff) == 0xffff)
		return 0;
	return 1;
}


void util_remove_trailing_chars(char *path, char c)
{
	size_t len;

	if (path == NULL)
		return;
	len = strlen(path);
	while (len > 0 && path[len-1] == c)
		path[--len] = '\0';
}


static int is_whitelisted(char c, const char *white)
{
	if ((c >= '0' && c <= '9') ||
	    (c >= 'A' && c <= 'Z') ||
	    (c >= 'a' && c <= 'z') ||
	    strchr("#+-.:=@_", c) != NULL ||
	    (white != NULL && strchr(white, c) != NULL))
		return 1;
	return 0;
}


static unsigned int irda_poll(struct file * file, struct socket *sock,
			      poll_table *wait)
{
	struct sock *sk = sock->sk;
	struct irda_sock *self = irda_sk(sk);
	unsigned int mask;

	IRDA_DEBUG(4, "%s()\n", __func__);

	poll_wait(file, sk->sk_sleep, wait);
	mask = 0;

	/* Exceptional events? */
	if (sk->sk_err)
		mask |= POLLERR;
	if (sk->sk_shutdown & RCV_SHUTDOWN) {
		IRDA_DEBUG(0, "%s(), POLLHUP\n", __func__);
		mask |= POLLHUP;
	}

	/* Readable? */
	if (!skb_queue_empty(&sk->sk_receive_queue)) {
		IRDA_DEBUG(4, "Socket is readable\n");
		mask |= POLLIN | POLLRDNORM;
	}

	/* Connection-based need to check for termination and startup */
	switch (sk->sk_type) {
	case SOCK_STREAM:
		if (sk->sk_state == TCP_CLOSE) {
			IRDA_DEBUG(0, "%s(), POLLHUP\n", __func__);
			mask |= POLLHUP;
		}

		if (sk->sk_state == TCP_ESTABLISHED) {
			if ((self->tx_flow == FLOW_START) &&
			    sock_writeable(sk))
			{
				mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
			}
		}
		break;
	case SOCK_SEQPACKET:
		if ((self->tx_flow == FLOW_START) &&
		    sock_writeable(sk))
		{
			mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
		}
		break;
	case SOCK_DGRAM:
		if (sock_writeable(sk))
			mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
		break;
	default:
		break;
	}
	return mask;
}

irda: Fix irda_getname() leak

irda_getname() can leak kernel memory to user.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>


static int irda_sendmsg_dgram(struct kiocb *iocb, struct socket *sock,
			      struct msghdr *msg, size_t len)
{
	struct sock *sk = sock->sk;
	struct irda_sock *self;
	struct sk_buff *skb;
	int err;

	IRDA_DEBUG(4, "%s(), len=%zd\n", __func__, len);

	if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_CMSG_COMPAT))
		return -EINVAL;

	if (sk->sk_shutdown & SEND_SHUTDOWN) {
		send_sig(SIGPIPE, current, 0);
		return -EPIPE;
	}

	if (sk->sk_state != TCP_ESTABLISHED)
		return -ENOTCONN;

	self = irda_sk(sk);

	/*
	 * Check that we don't send out too big frames. This is an unreliable
	 * service, so we have no fragmentation and no coalescence
	 */
	if (len > self->max_data_size) {
		IRDA_DEBUG(0, "%s(), Warning to much data! "
			   "Chopping frame from %zd to %d bytes!\n",
			   __func__, len, self->max_data_size);
		len = self->max_data_size;
	}

	skb = sock_alloc_send_skb(sk, len + self->max_header_size,
				  msg->msg_flags & MSG_DONTWAIT, &err);
	if (!skb)
		return -ENOBUFS;

	skb_reserve(skb, self->max_header_size);
	skb_reset_transport_header(skb);

	IRDA_DEBUG(4, "%s(), appending user data\n", __func__);
	skb_put(skb, len);
	err = memcpy_fromiovec(skb_transport_header(skb), msg->msg_iov, len);
	if (err) {
		kfree_skb(skb);
		return err;
	}

	/*
	 * Just send the message to TinyTP, and let it deal with possible
	 * errors. No need to duplicate all that here
	 */
	err = irttp_udata_request(self->tsap, skb);
	if (err) {
		IRDA_DEBUG(0, "%s(), err=%d\n", __func__, err);
		return err;
	}
	return len;
}


static int irda_find_lsap_sel(struct irda_sock *self, char *name)
{
	IRDA_DEBUG(2, "%s(%p, %s)\n", __func__, self, name);

	if (self->iriap) {
		IRDA_WARNING("%s(): busy with a previous query\n",
			     __func__);
		return -EBUSY;
	}

	self->iriap = iriap_open(LSAP_ANY, IAS_CLIENT, self,
				 irda_getvalue_confirm);
	if(self->iriap == NULL)
		return -ENOMEM;

	/* Treat unexpected wakeup as disconnect */
	self->errno = -EHOSTUNREACH;

	/* Query remote LM-IAS */
	iriap_getvaluebyclass_request(self->iriap, self->saddr, self->daddr,
				      name, "IrDA:TinyTP:LsapSel");

	/* Wait for answer, if not yet finished (or failed) */
	if (wait_event_interruptible(self->query_wait, (self->iriap==NULL)))
		/* Treat signals as disconnect */
		return -EHOSTUNREACH;

	/* Check what happened */
	if (self->errno)
	{
		/* Requested object/attribute doesn't exist */
		if((self->errno == IAS_CLASS_UNKNOWN) ||
		   (self->errno == IAS_ATTRIB_UNKNOWN))
			return (-EADDRNOTAVAIL);
		else
			return (-EHOSTUNREACH);
	}

	/* Get the remote TSAP selector */
	switch (self->ias_result->type) {
	case IAS_INTEGER:
		IRDA_DEBUG(4, "%s() int=%d\n",
			   __func__, self->ias_result->t.integer);

		if (self->ias_result->t.integer != -1)
			self->dtsap_sel = self->ias_result->t.integer;
		else
			self->dtsap_sel = 0;
		break;
	default:
		self->dtsap_sel = 0;
		IRDA_DEBUG(0, "%s(), bad type!\n", __func__);
		break;
	}
	if (self->ias_result)
		irias_delete_value(self->ias_result);

	if (self->dtsap_sel)
		return 0;

	return -EADDRNOTAVAIL;
}


static int irda_create(struct net *net, struct socket *sock, int protocol)
{
	struct sock *sk;
	struct irda_sock *self;

	IRDA_DEBUG(2, "%s()\n", __func__);

	if (net != &init_net)
		return -EAFNOSUPPORT;

	/* Check for valid socket type */
	switch (sock->type) {
	case SOCK_STREAM:     /* For TTP connections with SAR disabled */
	case SOCK_SEQPACKET:  /* For TTP connections with SAR enabled */
	case SOCK_DGRAM:      /* For TTP Unitdata or LMP Ultra transfers */
		break;
	default:
		return -ESOCKTNOSUPPORT;
	}

	/* Allocate networking socket */
	sk = sk_alloc(net, PF_IRDA, GFP_ATOMIC, &irda_proto);
	if (sk == NULL)
		return -ENOMEM;

	self = irda_sk(sk);
	IRDA_DEBUG(2, "%s() : self is %p\n", __func__, self);

	init_waitqueue_head(&self->query_wait);

	switch (sock->type) {
	case SOCK_STREAM:
		sock->ops = &irda_stream_ops;
		self->max_sdu_size_rx = TTP_SAR_DISABLE;
		break;
	case SOCK_SEQPACKET:
		sock->ops = &irda_seqpacket_ops;
		self->max_sdu_size_rx = TTP_SAR_UNBOUND;
		break;
	case SOCK_DGRAM:
		switch (protocol) {
#ifdef CONFIG_IRDA_ULTRA
		case IRDAPROTO_ULTRA:
			sock->ops = &irda_ultra_ops;
			/* Initialise now, because we may send on unbound
			 * sockets. Jean II */
			self->max_data_size = ULTRA_MAX_DATA - LMP_PID_HEADER;
			self->max_header_size = IRDA_MAX_HEADER + LMP_PID_HEADER;
			break;
#endif /* CONFIG_IRDA_ULTRA */
		case IRDAPROTO_UNITDATA:
			sock->ops = &irda_dgram_ops;
			/* We let Unitdata conn. be like seqpack conn. */
			self->max_sdu_size_rx = TTP_SAR_UNBOUND;
			break;
		default:
			sk_free(sk);
			return -ESOCKTNOSUPPORT;
		}
		break;
	default:
		sk_free(sk);
		return -ESOCKTNOSUPPORT;
	}

	/* Initialise networking socket struct */
	sock_init_data(sock, sk);	/* Note : set sk->sk_refcnt to 1 */
	sk->sk_family = PF_IRDA;
	sk->sk_protocol = protocol;

	/* Register as a client with IrLMP */
	self->ckey = irlmp_register_client(0, NULL, NULL, NULL);
	self->mask.word = 0xffff;
	self->rx_flow = self->tx_flow = FLOW_START;
	self->nslots = DISCOVERY_DEFAULT_SLOTS;
	self->daddr = DEV_ADDR_ANY;	/* Until we get connected */
	self->saddr = 0x0;		/* so IrLMP assign us any link */
	return 0;
}


static int irda_recvmsg_dgram(struct kiocb *iocb, struct socket *sock,
			      struct msghdr *msg, size_t size, int flags)
{
	struct sock *sk = sock->sk;
	struct irda_sock *self = irda_sk(sk);
	struct sk_buff *skb;
	size_t copied;
	int err;

	IRDA_DEBUG(4, "%s()\n", __func__);

	if ((err = sock_error(sk)) < 0)
		return err;

	skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
				flags & MSG_DONTWAIT, &err);
	if (!skb)
		return err;

	skb_reset_transport_header(skb);
	copied = skb->len;

	if (copied > size) {
		IRDA_DEBUG(2, "%s(), Received truncated frame (%zd < %zd)!\n",
			   __func__, copied, size);
		copied = size;
		msg->msg_flags |= MSG_TRUNC;
	}
	skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);

	skb_free_datagram(sk, skb);

	/*
	 *  Check if we have previously stopped IrTTP and we know
	 *  have more free space in our rx_queue. If so tell IrTTP
	 *  to start delivering frames again before our rx_queue gets
	 *  empty
	 */
	if (self->rx_flow == FLOW_STOP) {
		if ((atomic_read(&sk->sk_rmem_alloc) << 2) <= sk->sk_rcvbuf) {
			IRDA_DEBUG(2, "%s(), Starting IrTTP\n", __func__);
			self->rx_flow = FLOW_START;
			irttp_flow_request(self->tsap, FLOW_START);
		}
	}

	return copied;
}


static int irda_shutdown(struct socket *sock, int how)
{
	struct sock *sk = sock->sk;
	struct irda_sock *self = irda_sk(sk);

	IRDA_DEBUG(1, "%s(%p)\n", __func__, self);

	sk->sk_state       = TCP_CLOSE;
	sk->sk_shutdown   |= SEND_SHUTDOWN;
	sk->sk_state_change(sk);

	if (self->iriap) {
		iriap_close(self->iriap);
		self->iriap = NULL;
	}

	if (self->tsap) {
		irttp_disconnect_request(self->tsap, NULL, P_NORMAL);
		irttp_close_tsap(self->tsap);
		self->tsap = NULL;
	}

	/* A few cleanup so the socket look as good as new... */
	self->rx_flow = self->tx_flow = FLOW_START;	/* needed ??? */
	self->daddr = DEV_ADDR_ANY;	/* Until we get re-connected */
	self->saddr = 0x0;		/* so IrLMP assign us any link */

	return 0;
}


static int irda_sendmsg(struct kiocb *iocb, struct socket *sock,
			struct msghdr *msg, size_t len)
{
	struct sock *sk = sock->sk;
	struct irda_sock *self;
	struct sk_buff *skb;
	int err = -EPIPE;

	IRDA_DEBUG(4, "%s(), len=%zd\n", __func__, len);

	/* Note : socket.c set MSG_EOR on SEQPACKET sockets */
	if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_EOR | MSG_CMSG_COMPAT |
			       MSG_NOSIGNAL))
		return -EINVAL;

	if (sk->sk_shutdown & SEND_SHUTDOWN)
		goto out_err;

	if (sk->sk_state != TCP_ESTABLISHED)
		return -ENOTCONN;

	self = irda_sk(sk);

	/* Check if IrTTP is wants us to slow down */

	if (wait_event_interruptible(*(sk->sk_sleep),
	    (self->tx_flow != FLOW_STOP  ||  sk->sk_state != TCP_ESTABLISHED)))
		return -ERESTARTSYS;

	/* Check if we are still connected */
	if (sk->sk_state != TCP_ESTABLISHED)
		return -ENOTCONN;

	/* Check that we don't send out too big frames */
	if (len > self->max_data_size) {
		IRDA_DEBUG(2, "%s(), Chopping frame from %zd to %d bytes!\n",
			   __func__, len, self->max_data_size);
		len = self->max_data_size;
	}

	skb = sock_alloc_send_skb(sk, len + self->max_header_size + 16,
				  msg->msg_flags & MSG_DONTWAIT, &err);
	if (!skb)
		goto out_err;

	skb_reserve(skb, self->max_header_size + 16);
	skb_reset_transport_header(skb);
	skb_put(skb, len);
	err = memcpy_fromiovec(skb_transport_header(skb), msg->msg_iov, len);
	if (err) {
		kfree_skb(skb);
		goto out_err;
	}

	/*
	 * Just send the message to TinyTP, and let it deal with possible
	 * errors. No need to duplicate all that here
	 */
	err = irttp_data_request(self->tsap, skb);
	if (err) {
		IRDA_DEBUG(0, "%s(), err=%d\n", __func__, err);
		goto out_err;
	}
	/* Tell client how much data we actually sent */
	return len;

 out_err:
	return sk_stream_error(sk, msg->msg_flags, err);

}