[PATCH AUTOSEL 6.1 46/61] udf: Avoid excessive partition lengths

Sasha Levin
2024-08-01T00:30:56Z

From: Jan Kara <jack@suse.cz>

[ Upstream commit ebbe26fd54a9621994bc16b14f2ba8f84c089693 ]

Avoid mounting filesystems where the partition would overflow the
32-bits used for block number. Also refuse to mount filesystems where
the partition length is so large we cannot safely index bits in a
block bitmap.

Link: https://patch.msgid.link/20240620130403.14731-1-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/udf/super.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 6dc9d8dad88eb..f58ce0ba66130 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1076,12 +1076,19 @@ static int udf_fill_partdesc_info(struct super_block *sb,
struct udf_part_map *map;
struct udf_sb_info *sbi = UDF_SB(sb);
struct partitionHeaderDesc *phd;
+ u32 sum;
int err;

map = &sbi->s_partmaps[p_index];

map->s_partition_len = le32_to_cpu(p->partitionLength); /* blocks */
map->s_partition_root = le32_to_cpu(p->partitionStartingLocation);
+ if (check_add_overflow(map->s_partition_root, map->s_partition_len,
+ &sum)) {
+ udf_err(sb, "Partition %d has invalid location %u + %u\n",
+ p_index, map->s_partition_root, map->s_partition_len);
+ return -EFSCORRUPTED;
+ }

if (p->accessType == cpu_to_le32(PD_ACCESS_TYPE_READ_ONLY))
map->s_partition_flags |= UDF_PART_FLAG_READ_ONLY;
@@ -1137,6 +1144,14 @@ static int udf_fill_partdesc_info(struct super_block *sb,
bitmap->s_extPosition = le32_to_cpu(
phd->unallocSpaceBitmap.extPosition);
map->s_partition_flags |= UDF_PART_FLAG_UNALLOC_BITMAP;
+ /* Check whether math over bitmap won't overflow. */
+ if (check_add_overflow(map->s_partition_len,
+ sizeof(struct spaceBitmapDesc) << 3,
+ &sum)) {
+ udf_err(sb, "Partition %d is too long (%u)\n", p_index,
+ map->s_partition_len);
+ return -EFSCORRUPTED;
+ }
udf_debug("unallocSpaceBitmap (part %d) @ %u\n",
p_index, bitmap->s_extPosition);
}
--
2.43.0