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Commit adee11b2 authored by Jan Kara's avatar Jan Kara
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udf: Avoid run away loop when partition table length is corrupted 



Check provided length of partition table so that (possibly maliciously)
corrupted partition table cannot cause accessing data beyond current buffer.

Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent cb14d340

fs/udf/super.c

+9 −1
Original line number Diff line number Diff line
@@ -1225,6 +1225,7 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block, 
	struct genericPartitionMap *gpm;

	uint16_t ident;

	struct buffer_head *bh;

	unsigned int table_len;

	int ret = 0;



	bh = udf_read_tagged(sb, block, block, &ident);
@@ -1232,13 +1233,20 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block, 
		return 1;

	BUG_ON(ident != TAG_IDENT_LVD);

	lvd = (struct logicalVolDesc *)bh->b_data;

	table_len = le32_to_cpu(lvd->mapTableLength);

	if (sizeof(*lvd) + table_len > sb->s_blocksize) {

		udf_err(sb, "error loading logical volume descriptor: "

			"Partition table too long (%u > %lu)\n", table_len,

			sb->s_blocksize - sizeof(*lvd));

		goto out_bh;

	}



	ret = udf_sb_alloc_partition_maps(sb, le32_to_cpu(lvd->numPartitionMaps));

	if (ret)

		goto out_bh;



	for (i = 0, offset = 0;

	     i < sbi->s_partitions && offset < le32_to_cpu(lvd->mapTableLength);

	     i < sbi->s_partitions && offset < table_len;

	     i++, offset += gpm->partitionMapLength) {

		struct udf_part_map *map = &sbi->s_partmaps[i];

		gpm = (struct genericPartitionMap *)