Re: [PATCH] lib/crypto: Enable more algorithms in cert verification

[Ilias Apalodimas <ilias.apalodimas@linaro.org>]

Hi Heinrich, 

> > > > -		info.checksum = image_get_checksum_algo("sha256,rsa2048");

[...]

> > > > -		info.name = "sha256,rsa2048";
> > > > -	} else {
> > > > -		pr_warn("unknown msg digest algo: %s\n", sig->hash_algo);
> > > > +	if (strcmp(sig->pkey_algo, "rsa")) {
> > > > +		pr_err("Encryption is not RSA: %s\n", sig->pkey_algo);
> > > >   		return -ENOPKG;
> > > >   	}
> > > > +	ret = snprintf(algo, sizeof(algo), "%s,%s%d", sig->hash_algo,
> > > > +		       sig->pkey_algo, sig->s_size * 8);
> 
> How do we ensure that the unsafe SHA1 algorithm is not used?

We don't,  but the current code allows it as well.  Should we enforce this
from U-Boot  though?  The spec doesn't forbid it as far as I remember

Regards
/Ilias
> 
> Best regards
> 
> Heinrich
> 
> > > 
> > > I'm not sure that this naming rule, in particular the latter part, will
> > > always hold in the future while all the existing algo's observe it.
> > > (Maybe we need some note somewhere?)
> > 
> > The if a few lines below will shield us and return -EINVAL.  How about
> > adding an error message there?
> > 
> > Cheers
> > /Ilias
> > > 
> > > -Takahiro Akashi
> > > 
> > > > +
> > > > +	if (ret >= sizeof(algo))
> > > > +		return -EINVAL;
> > > > +
> > > > +	info.checksum = image_get_checksum_algo((const char *)algo);
> > > > +	info.name = (const char *)algo;
> > > >   	info.crypto = image_get_crypto_algo(info.name);
> > > > -	if (IS_ERR(info.checksum) || IS_ERR(info.crypto))
> > > > +	if (!info.checksum || !info.crypto)
> > > >   		return -ENOPKG;
> > > > 
> > > >   	info.key = pkey->key;
> > > > --
> > > > 2.30.2
> > > > 
>