Patch "udf: Avoid excessive partition lengths" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    udf: Avoid excessive partition lengths

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     udf-avoid-excessive-partition-lengths.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 946213db61fdf4817b39c905896a333b42ad0cfb
Author: Jan Kara <jack@xxxxxxx>
Date:   Thu Jun 20 12:52:17 2024 +0200

    udf: Avoid excessive partition lengths
    
    [ 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@xxxxxxx
    Signed-off-by: Jan Kara <jack@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 8691f7c31bf9..4275d2bc0c36 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1084,12 +1084,19 @@ 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;
@@ -1145,6 +1152,14 @@ 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);
 	}