[dm-devel] [PATCH] dm-integrity: fix a BUG if we shrink the device

[Milan Broz]

On 26/03/2022 15:24, Mikulas Patocka wrote:
> The patch f6f72f32c22c ("dm integrity: don't replay journal data past the
> end of the device") skips journal replay if the target sector points
> beyond the end of the device. Unfortunatelly, it doesn't set the journal
> entry unused, which resulted in this BUG being triggered:
> BUG_ON(!journal_entry_is_unused(je))
> 
> This patch fixes the crash.
> 
> Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>
> Fixes: f6f72f32c22c ("dm integrity: don't replay journal data past the end of the device")
> Cc: stable at vger.kernel.org	# v5.7+
> 
> ---
>   drivers/md/dm-integrity.c |    6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> Index: linux-dm/drivers/md/dm-integrity.c
> ===================================================================
> --- linux-dm.orig/drivers/md/dm-integrity.c	2022-02-10 18:16:42.000000000 +0100
> +++ linux-dm/drivers/md/dm-integrity.c	2022-03-25 18:20:27.000000000 +0100
> @@ -2473,9 +2473,11 @@ static void do_journal_write(struct dm_i
>   					dm_integrity_io_error(ic, "invalid sector in journal", -EIO);
>   					sec &= ~(sector_t)(ic->sectors_per_block - 1);
>   				}
> +				if (unlikely(sec >= ic->provided_data_sectors)) {
> +					journal_entry_set_unused(je);
> +					continue;
> +				}
>   			}
> -			if (unlikely(sec >= ic->provided_data_sectors))
> -				continue;
>   			get_area_and_offset(ic, sec, &area, &offset);
>   			restore_last_bytes(ic, access_journal_data(ic, i, j), je);
>   			for (k = j + 1; k < ic->journal_section_entries; k++) {
> 

If it helps anything,
Tested-by: Milan Broz <gmazyland at gmail.com>

Mike, please send this to stable ASAP, this is a quite serious bug.

Thanks,
Milan