udf: Avoid run away loop when partition table length is corrupted
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 <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/udf/super.c b/fs/udf/super.c
index 9da6f4e..ce911f5 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1225,6 +1225,7 @@
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 @@
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 *)