Re: [PATCH 02/18] asymmetric keys: implementEMSA_PKCS1-v1_5-ENCODE in rsa

[joeyli]

Hi Pavel, 

First, thanks for your review!

æ æï2013-08-25 æ 17:53 +0200ïPavel Machek æåï
> On Thu 2013-08-22 19:01:41, Lee, Chun-Yi wrote:
> > Implement EMSA_PKCS1-v1_5-ENCODE [RFC3447 sec 9.2] in rsa.c. It's the
> > first step of signature generation operation
> > (RSASSA-PKCS1-v1_5-SIGN).
> 
> Is this your own code, or did you copy it from somewhere?
> 

It's my own code, development base on RSA PKCS#1 spec. So the naming of
variables are match with PKCS#1 spec.

> > +	if (!T)
> > +		goto error_T;
> > +
> > +	memcpy(T, RSA_ASN1_templates[hash_algo].data, RSA_ASN1_templates[hash_algo].size);
> > +	memcpy(T + RSA_ASN1_templates[hash_algo].size, pks->digest, pks->digest_size);
> > +
> > +	/* 3) check If emLen < tLen + 11, output "intended encoded message length too short" */
> > +	if (emLen < tLen + 11) {
> > +		ret = EINVAL;
> > +		goto error_emLen;
> > +	}
> 
> Normal kernel calling convention is 0 / -EINVAL.

Yes, here is my mistake, I will modify it.

> 
> > +	memcpy(EM + 2, PS, emLen - tLen - 3);
> > +	EM[2 + emLen - tLen - 3] = 0x00;
> > +	memcpy(EM + 2 + emLen - tLen - 3 + 1, T, tLen);
> 
> ThisDoesNotLookLikeKernelCode, NoCamelCase, please.
> 

Thanks for you point out, I will change it.

> > +	*_EM = EM;
> 
> And we don't usually use _ prefix like this.
> 

Thanks! I will change it.

> 
> > --- a/include/crypto/public_key.h
> > +++ b/include/crypto/public_key.h
> > @@ -110,6 +110,8 @@ extern void public_key_destroy(void *payload);
> >  struct public_key_signature {
> >  	u8 *digest;
> >  	u8 digest_size;			/* Number of bytes in digest */
> > +	u8 *S;				/* signature S of length k octets */
> 
> u8 *signature?

Yes, this 'S' is signature. I put the naming full match with spec for
development, I will change it to match kernel rule. e.g. signature_S

> 
> > +	size_t k;			/* length k of signature S */
> 
> u8 *signature_length.
> 

I will use signature_leng_k to also match with PKCS#1 spec, I think it's
better for review source code with the spec for debugging.


Thanks a lot!
Joey Lee

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