Re: [PATCH v3 2/2] fscrypt: Add SM4 XTS/CTS symmetric algorithm support

[Tianjia Zhang]

Hi Eric,

On 11/26/22 2:24 AM, Eric Biggers wrote:
> On Fri, Nov 25, 2022 at 08:16:30PM +0800, Tianjia Zhang wrote:
> > diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
> > index 46757c3052ef..8e69bc0c35cd 100644
> > --- a/fs/crypto/policy.c
> > +++ b/fs/crypto/policy.c
> > @@ -71,6 +71,10 @@ static bool fscrypt_valid_enc_modes_v1(u32 contents_mode, u32 filenames_mode)
> >   	    filenames_mode == FSCRYPT_MODE_AES_128_CTS)
> >   		return true;
> >   
> > +	if (contents_mode == FSCRYPT_MODE_SM4_XTS &&
> > +	    filenames_mode == FSCRYPT_MODE_SM4_CTS)
> > +		return true;
> > +
> >   	if (contents_mode == FSCRYPT_MODE_ADIANTUM &&
> >   	    filenames_mode == FSCRYPT_MODE_ADIANTUM)
> >   		return true;
>
> Sorry, one more thing I didn't notice before.  Since this is a new feature,
> please only allow it in fscrypt_valid_enc_modes_v2(), not in
> fscrypt_valid_enc_modes_v1().  That's what we did for AES-256-XTS +
> AES-256-HCTR2 recently.  There should be no need to add new features to
> v1 encryption policies, which have been deprecated for several years.
>
> - Eric

Thanks for reminder, it makes sense to only support the new algorithm in
v2 policy, which I will do this.

BR,
Tianjia