linux-kernel - [PATCH AUTOSEL 5.4 13/22] udf: Avoid excessive partition lengths

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Message-ID: <20240801003918.3939431-13-sashal@kernel.org>
Date: Wed, 31 Jul 2024 20:38:42 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Jan Kara <jack@...e.cz>,
	Sasha Levin <sashal@...nel.org>,
	jack@...e.com
Subject: [PATCH AUTOSEL 5.4 13/22] udf: Avoid excessive partition lengths

From: Jan Kara <jack@...e.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@...e.cz>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/udf/super.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 0f8b3cb355852..2d3eabf955c55 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1082,12 +1082,19 @@ 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;
@@ -1143,6 +1150,14 @@ 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