Re: [PATCH v1 1/1] dm-inlinecrypt: initialize blk-crypto key as HW-wrapped key

[Eric Biggers]

On Tue, May 12, 2026 at 06:53:35PM +0000, Eric Biggers wrote:
> On Tue, May 12, 2026 at 02:52:03AM -0700, Linlin Zhang wrote:
> > dm-inlinecrypt currently initializes the blk-crypto key using
> > BLK_CRYPTO_KEY_TYPE_RAW, which implies that the provided key material
> > is a plaintext software key owned by the block layer.
> > 
> > However, on platforms where dm-inlinecrypt is used together with a
> > hardware-backed key source (e.g. TrustZone/TEE or other secure key
> > wrapping mechanisms), the key material passed down is already wrapped
> > and must be treated as opaque by the block layer.
> > 
> > Initialize the blk-crypto key using BLK_CRYPTO_KEY_TYPE_HW_WRAPPED
> > instead, so that dm-inlinecrypt correctly models hardware-wrapped keys
> > and avoids incorrect assumptions about key ownership and visibility.
> > 
> > Signed-off-by: Linlin Zhang <linlin.zhang@xxxxxxxxxxxxxxxx>
> > ---
> >  drivers/md/dm-inlinecrypt.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/md/dm-inlinecrypt.c b/drivers/md/dm-inlinecrypt.c
> > index bd8e58a028c5..bcbf363c533a 100644
> > --- a/drivers/md/dm-inlinecrypt.c
> > +++ b/drivers/md/dm-inlinecrypt.c
> > @@ -386,7 +386,7 @@ static int inlinecrypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
> >  	dun_bytes = DIV_ROUND_UP(fls64(ctx->max_dun), 8);
> >  
> >  	err = blk_crypto_init_key(&ctx->key, raw_key, ctx->key_size,
> > -				  BLK_CRYPTO_KEY_TYPE_RAW,
> > +				  BLK_CRYPTO_KEY_TYPE_HW_WRAPPED,
> >  				  cipher->mode_num, dun_bytes,
> >  				  ctx->sector_size);
> 
> The raw key support is useful too, and it should be the default.
> I recommend adding a "wrappedkey" optional argument that enables
> BLK_CRYPTO_KEY_TYPE_HW_WRAPPED.

This patch also makes the variable called "raw_key" contain a key that
isn't a raw key, which is confusing.  "key_bytes" would make more sense
for a byte array that can contain either type of key.  See e.g.
blk_crypto_init_key() which uses that naming convention.

- Eric