Messages in this thread | | | Subject | Re: [PATCH 2/4] KEYS: trusted: allow trust sources to use kernel RNG for key material | From | Ahmad Fatoum <> | Date | Mon, 9 Aug 2021 09:52:20 +0200 |
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Hello Sumit,
On 22.07.21 08:31, Sumit Garg wrote: > On Wed, 21 Jul 2021 at 22:19, Ahmad Fatoum <a.fatoum@pengutronix.de> wrote: >> >> The two existing trusted key sources don't make use of the kernel RNG, >> but instead let the hardware that does the sealing/unsealing also >> generate the random key material. While a previous change offers users >> the choice to use the kernel RNG instead for both, new trust sources >> may want to unconditionally use the kernel RNG for generating key >> material, like it's done elsewhere in the kernel. >> >> This is especially prudent for hardware that has proven-in-production >> HWRNG drivers implemented, as otherwise code would have to be duplicated >> only to arrive at a possibly worse result. >> >> Make this possible by turning struct trusted_key_ops::get_random >> into an optional member. If a driver leaves it NULL, kernel RNG >> will be used instead. >> >> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de> >> --- >> To: James Bottomley <jejb@linux.ibm.com> >> To: Jarkko Sakkinen <jarkko@kernel.org> >> To: Mimi Zohar <zohar@linux.ibm.com> >> To: David Howells <dhowells@redhat.com> >> Cc: James Morris <jmorris@namei.org> >> Cc: "Serge E. Hallyn" <serge@hallyn.com> >> Cc: "Horia Geantă" <horia.geanta@nxp.com> >> Cc: Aymen Sghaier <aymen.sghaier@nxp.com> >> Cc: Herbert Xu <herbert@gondor.apana.org.au> >> Cc: "David S. Miller" <davem@davemloft.net> >> Cc: Udit Agarwal <udit.agarwal@nxp.com> >> Cc: Eric Biggers <ebiggers@kernel.org> >> Cc: Jan Luebbe <j.luebbe@pengutronix.de> >> Cc: David Gstir <david@sigma-star.at> >> Cc: Richard Weinberger <richard@nod.at> >> Cc: Franck LENORMAND <franck.lenormand@nxp.com> >> Cc: Sumit Garg <sumit.garg@linaro.org> >> Cc: keyrings@vger.kernel.org >> Cc: linux-crypto@vger.kernel.org >> Cc: linux-integrity@vger.kernel.org >> Cc: linux-kernel@vger.kernel.org >> Cc: linux-security-module@vger.kernel.org >> --- >> include/keys/trusted-type.h | 2 +- >> security/keys/trusted-keys/trusted_core.c | 2 +- >> 2 files changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h >> index d89fa2579ac0..4eb64548a74f 100644 >> --- a/include/keys/trusted-type.h >> +++ b/include/keys/trusted-type.h >> @@ -64,7 +64,7 @@ struct trusted_key_ops { >> /* Unseal a key. */ >> int (*unseal)(struct trusted_key_payload *p, char *datablob); >> >> - /* Get a randomized key. */ >> + /* Optional: Get a randomized key. */ >> int (*get_random)(unsigned char *key, size_t key_len); >> >> /* Exit key interface. */ >> diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c >> index 569af9af8df0..d2b7626cde8b 100644 >> --- a/security/keys/trusted-keys/trusted_core.c >> +++ b/security/keys/trusted-keys/trusted_core.c >> @@ -334,7 +334,7 @@ static int __init init_trusted(void) >> continue; >> >> get_random = trusted_key_sources[i].ops->get_random; >> - if (trusted_kernel_rng) >> + if (trusted_kernel_rng || !get_random) >> get_random = kernel_get_random; >> > > For ease of understanding, I would prefer to write it as: > > get_random = trusted_key_sources[i].ops->get_random ?: > kernel_get_random; > if (trusted_kernel_rng) > get_random = kernel_get_random; > > With that: > > Acked-by: Sumit Garg <sumit.garg@linaro.org>
I don't think it improves readability to split up the conditional. At least I need to take a second pass over the code to understand the second conditional.
Cheers, Ahmad
> > -Sumit > >> static_call_update(trusted_key_init, >> -- >> git-series 0.9.1 >
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