dm-crypt: don't modify the data when using authenticated encryption

commit 50c70240097ce41fe6bce6478b80478281e4d0f7 upstream.

It was said that authenticated encryption could produce invalid tag when
the data that is being encrypted is modified [1]. So, fix this problem by
copying the data into the clone bio first and then encrypt them inside the
clone bio.

This may reduce performance, but it is needed to prevent the user from
corrupting the device by writing data with O_DIRECT and modifying them at
the same time.

[1] https://lore.kernel.org/all/20240207004723.GA35324@sol.localdomain/T/

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index a428770102a37989b3319b9cb03bbab7faac24dc..5904af05f6057c21c52211760bb90d30262139a9 100644 (file)
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -2065,6 +2065,12 @@ static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
        io->ctx.bio_out = clone;
        io->ctx.iter_out = clone->bi_iter;
 
+       if (crypt_integrity_aead(cc)) {
+               bio_copy_data(clone, io->base_bio);
+               io->ctx.bio_in = clone;
+               io->ctx.iter_in = clone->bi_iter;
+       }
+
        sector += bio_sectors(clone);
 
        crypt_inc_pending(io);