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Message-ID: <e0461754-39c4-a9e1-6ca1-381659e4a2d7@linux.alibaba.com>
Date:   Mon, 28 Nov 2022 15:35:37 +0800
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Subject: Re: [PATCH v3 2/2] fscrypt: Add SM4 XTS/CTS symmetric algorithm
 support
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To:     Eric Biggers <ebiggers@kernel.org>
Cc:     "Theodore Y. Ts o" <tytso@mit.edu>,
        Jaegeuk Kim <jaegeuk@kernel.org>,
        Jonathan Corbet <corbet@lwn.net>, Jens Axboe <axboe@kernel.dk>,
        Ard Biesheuvel <ardb@kernel.org>,
        linux-fscrypt@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-block@vger.kernel.org
References: <20221125121630.87793-1-tianjia.zhang@linux.alibaba.com>
 <20221125121630.87793-3-tianjia.zhang@linux.alibaba.com>
 <Y4EIR+n8aKutuLo0@sol.localdomain>
From:   Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
In-Reply-To: <Y4EIR+n8aKutuLo0@sol.localdomain>
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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