From: David Howells <dhowells@redhat.com>
Subject: Re: v4.6-rc1 regression bisected, Problem loading in-kernel X.509 certificate (-2)
Date: Tue, 03 May 2016 21:35:40 +0100
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Cc: dhowells@redhat.com, Herbert Xu <herbert@gondor.apana.org.au>,
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To: Jamie Heilman <jamie@audible.transient.net>
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(cc'ing Tadeusz as he did the pkcs1 padding function)

Jamie Heilman <jamie@audible.transient.net> wrote:

> > > Problem loading in-kernel X.509 certificate (-2)
> > 
> > ENOENT?  Hmmm...  The only place that is generated is in the crypto layer.
> > That suggests missing crypto of some sort.
> > 
> > The attached patch enables some debugging in some relevant files if you can
> > try applying it to your kernel.
> 
> Alrighty, presumably relevant bits:
>
> X.509: Cert Issuer: Build time autogenerated kernel key
> X.509: Cert Subject: Build time autogenerated kernel key
> X.509: Cert Key Algo: rsa
> X.509: Cert Valid period: 1461826791-4615426791
> X.509: Cert Signature: rsa + sha512
> X.509: ==>x509_check_signature()
> X.509: ==>x509_get_sig_params()
> X.509: <==x509_get_sig_params() = 0
> PKEY: ==>public_key_verify_signature()
> X.509: Cert Verification: -2

Hmmm...  Okay, the only ways out of public_key_verify_signature() without
printing a leaving message are for snprintf() to overrun (which would return
error -22) or for crypto_alloc_akcipher() to have failed; everything else must
go through the kleave() at the pr_devel() at the bottom of the function.

Can you stick:

	pr_devel("ALGO: %s\n", alg_name);

immediately before this line:

	tfm = crypto_alloc_akcipher(alg_name, 0, 0);

and try it again?

Thanks,
David