dm raid: ensure superblock's size matches device's logical block size
The dm-raid superblock (struct dm_raid_superblock) is padded to 512
bytes and that size is being used to read it in from the metadata
device into one preallocated page.
Reading or writing this on a 512-byte sector device works fine but on
a 4096-byte sector device this fails.
Set the dm-raid superblock's size to the logical block size of the
metadata device, because IO at that size is guaranteed too work. Also
add a size check to avoid silent partial metadata loss in case the
superblock should ever grow past the logical block size or PAGE_SIZE.
[includes pointer math fix from Dan Carpenter]
Reported-by: "Liuhua Wang" <lwang@suse.com>
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 4857fa4..a7cb9dd 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -789,8 +789,7 @@
__le32 layout;
__le32 stripe_sectors;
- __u8 pad[452]; /* Round struct to 512 bytes. */
- /* Always set to 0 when writing. */
+ /* Remainder of a logical block is zero-filled when writing (see super_sync()). */
} __packed;
static int read_disk_sb(struct md_rdev *rdev, int size)
@@ -827,7 +826,7 @@
test_bit(Faulty, &(rs->dev[i].rdev.flags)))
failed_devices |= (1ULL << i);
- memset(sb, 0, sizeof(*sb));
+ memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
sb->magic = cpu_to_le32(DM_RAID_MAGIC);
sb->features = cpu_to_le32(0); /* No features yet */
@@ -862,7 +861,11 @@
uint64_t events_sb, events_refsb;
rdev->sb_start = 0;
- rdev->sb_size = sizeof(*sb);
+ rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
+ if (rdev->sb_size < sizeof(*sb) || rdev->sb_size > PAGE_SIZE) {
+ DMERR("superblock size of a logical block is no longer valid");
+ return -EINVAL;
+ }
ret = read_disk_sb(rdev, rdev->sb_size);
if (ret)