From adee11b2085bee90bd8f4f52123ffb07882d6256 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Wed, 27 Jun 2012 20:20:22 +0200 Subject: udf: Avoid run away loop when partition table length is corrupted From: Jan Kara commit adee11b2085bee90bd8f4f52123ffb07882d6256 upstream. Check provided length of partition table so that (possibly maliciously) corrupted partition table cannot cause accessing data beyond current buffer. Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman --- fs/udf/super.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/fs/udf/super.c +++ b/fs/udf/super.c @@ -1225,6 +1225,7 @@ static int udf_load_logicalvol(struct su 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 su 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 *)