On Mon, Oct 11, 2021 at 12:02:34PM +0200, Ahmad Fatoum wrote: > With recent rework, trusted keys are no longer limited to TPM as trust > source. The Kconfig symbol is unchanged however leading to a few issues: > > - TCG_TPM is required, even if only TEE is to be used > - Enabling TCG_TPM, but excluding it from available trusted sources > is not possible > - TEE=m && TRUSTED_KEYS=y will lead to TEE support being silently > dropped, which is not the best user experience > > Remedy these issues by introducing two new boolean Kconfig symbols: > TRUSTED_KEYS_TPM and TRUSTED_KEYS_TEE with the appropriate > dependencies. > > Any code depending on the TPM trusted key backend or symbols exported > by it will now need to explicitly state that it > > depends on TRUSTED_KEYS && TRUSTED_KEYS_TPM > > The latter to ensure the dependency is built and the former to ensure > it's reachable for module builds. This currently only affects > CONFIG_ASYMMETRIC_TPM_KEY_SUBTYPE, so it's fixed up here as well. > > Reviewed-by: Sumit Garg <sumit.garg@xxxxxxxxxx> > Tested-By: Andreas Rammhold <andreas@xxxxxxxxxxx> > Tested-By: Tim Harvey <tharvey@xxxxxxxxxxxxx> > Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx> > --- > v3 -> v4: > - rebased on top of Andreas' regression fix and pulled it back > into series > > v2 -> v3: > - factored this patch out as a fix for backporting > > v1 -> v2: > - Move rest of TPM-related selects from TRUSTED_KEYS to > TRUSTED_KEYS_TPM (Sumit) > - Remove left-over line in Makefile (Sumit) > - added Fixes: tag > - adjust commit message to reference the regression reported > by Andreas > - have ASYMMETRIC_TPM_KEY_SUBTYPE depend on TRUSTED_KEYS_TPM, > because it references global symbols that are exported > by the trusted key TPM backend. > > [1]: https://lore.kernel.org/linux-integrity/f8285eb0135ba30c9d846cf9dd395d1f5f8b1efc.1624364386.git-series.a.fatoum@xxxxxxxxxxxxxx/ > [2]: https://lore.kernel.org/linux-integrity/20210719091335.vwfebcpkf4pag3wm@wrt/T/#t > > To: Jarkko Sakkinen <jarkko@xxxxxxxxxx> > To: James Morris <jmorris@xxxxxxxxx> > To: "Serge E. Hallyn" <serge@xxxxxxxxxx> > To: James Bottomley <jejb@xxxxxxxxxxxxx> > To: Mimi Zohar <zohar@xxxxxxxxxxxxx> > To: Sumit Garg <sumit.garg@xxxxxxxxxx> > To: David Howells <dhowells@xxxxxxxxxx> > To: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> > To: "David S. Miller" <davem@xxxxxxxxxxxxx> > Cc: David Gstir <david@xxxxxxxxxxxxx> > Cc: Richard Weinberger <richard@xxxxxx> > Cc: keyrings@xxxxxxxxxxxxxxx > Cc: linux-crypto@xxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > Cc: linux-security-module@xxxxxxxxxxxxxxx > Cc: linux-integrity@xxxxxxxxxxxxxxx > --- > crypto/asymmetric_keys/Kconfig | 2 +- > security/keys/Kconfig | 18 +++++---------- > security/keys/trusted-keys/Kconfig | 29 ++++++++++++++++++++++++- > security/keys/trusted-keys/Makefile | 8 +++---- > security/keys/trusted-keys/trusted_core.c | 4 +-- > 5 files changed, 43 insertions(+), 18 deletions(-) > create mode 100644 security/keys/trusted-keys/Kconfig > > diff --git a/crypto/asymmetric_keys/Kconfig b/crypto/asymmetric_keys/Kconfig > index 1f1f004dc757..8886eddbf881 100644 > --- a/crypto/asymmetric_keys/Kconfig > +++ b/crypto/asymmetric_keys/Kconfig > @@ -25,7 +25,7 @@ config ASYMMETRIC_PUBLIC_KEY_SUBTYPE > config ASYMMETRIC_TPM_KEY_SUBTYPE > tristate "Asymmetric TPM backed private key subtype" > depends on TCG_TPM > - depends on TRUSTED_KEYS > + depends on TRUSTED_KEYS && TRUSTED_KEYS_TPM > select CRYPTO_HMAC > select CRYPTO_SHA1 > select CRYPTO_HASH_INFO > diff --git a/security/keys/Kconfig b/security/keys/Kconfig > index 64b81abd087e..9ec302962fe2 100644 > --- a/security/keys/Kconfig > +++ b/security/keys/Kconfig > @@ -70,23 +70,19 @@ config BIG_KEYS > > config TRUSTED_KEYS > tristate "TRUSTED KEYS" > - depends on KEYS && TCG_TPM > - select CRYPTO > - select CRYPTO_HMAC > - select CRYPTO_SHA1 > - select CRYPTO_HASH_INFO > - select ASN1_ENCODER > - select OID_REGISTRY > - select ASN1 > + depends on KEYS > help > This option provides support for creating, sealing, and unsealing > keys in the kernel. Trusted keys are random number symmetric keys, > - generated and RSA-sealed by the TPM. The TPM only unseals the keys, > - if the boot PCRs and other criteria match. Userspace will only ever > - see encrypted blobs. > + generated and sealed by a trust source selected at kernel boot-time. > + Userspace will only ever see encrypted blobs. > > If you are unsure as to whether this is required, answer N. > > +if TRUSTED_KEYS > +source "security/keys/trusted-keys/Kconfig" > +endif > + > config ENCRYPTED_KEYS > tristate "ENCRYPTED KEYS" > depends on KEYS > diff --git a/security/keys/trusted-keys/Kconfig b/security/keys/trusted-keys/Kconfig > new file mode 100644 > index 000000000000..fc4abd581abb > --- /dev/null > +++ b/security/keys/trusted-keys/Kconfig > @@ -0,0 +1,29 @@ > +config TRUSTED_KEYS_TPM > + bool "TPM-based trusted keys" > + depends on TCG_TPM >= TRUSTED_KEYS > + default y > + select CRYPTO > + select CRYPTO_HMAC > + select CRYPTO_SHA1 > + select CRYPTO_HASH_INFO > + select ASN1_ENCODER > + select OID_REGISTRY > + select ASN1 > + help > + Enable use of the Trusted Platform Module (TPM) as trusted key > + backend. Trusted keys are random number symmetric keys, > + which will be generated and RSA-sealed by the TPM. > + The TPM only unseals the keys, if the boot PCRs and other > + criteria match. > + > +config TRUSTED_KEYS_TEE > + bool "TEE-based trusted keys" > + depends on TEE >= TRUSTED_KEYS > + default y > + help > + Enable use of the Trusted Execution Environment (TEE) as trusted > + key backend. > + > +if !TRUSTED_KEYS_TPM && !TRUSTED_KEYS_TEE > +comment "No trust source selected!" > +endif > diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile > index feb8b6c3cc79..2e2371eae4d5 100644 > --- a/security/keys/trusted-keys/Makefile > +++ b/security/keys/trusted-keys/Makefile > @@ -5,10 +5,10 @@ > > obj-$(CONFIG_TRUSTED_KEYS) += trusted.o > trusted-y += trusted_core.o > -trusted-y += trusted_tpm1.o > +trusted-$(CONFIG_TRUSTED_KEYS_TPM) += trusted_tpm1.o > > $(obj)/trusted_tpm2.o: $(obj)/tpm2key.asn1.h > -trusted-y += trusted_tpm2.o > -trusted-y += tpm2key.asn1.o > +trusted-$(CONFIG_TRUSTED_KEYS_TPM) += trusted_tpm2.o > +trusted-$(CONFIG_TRUSTED_KEYS_TPM) += tpm2key.asn1.o > > -trusted-$(CONFIG_TEE) += trusted_tee.o > +trusted-$(CONFIG_TRUSTED_KEYS_TEE) += trusted_tee.o > diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c > index 5b35f1b87644..8cab69e5d0da 100644 > --- a/security/keys/trusted-keys/trusted_core.c > +++ b/security/keys/trusted-keys/trusted_core.c > @@ -27,10 +27,10 @@ module_param_named(source, trusted_key_source, charp, 0); > MODULE_PARM_DESC(source, "Select trusted keys source (tpm or tee)"); > > static const struct trusted_key_source trusted_key_sources[] = { > -#if IS_REACHABLE(CONFIG_TCG_TPM) > +#if defined(CONFIG_TRUSTED_KEYS_TPM) > { "tpm", &trusted_key_tpm_ops }, > #endif > -#if IS_REACHABLE(CONFIG_TEE) > +#if defined(CONFIG_TRUSTED_KEYS_TEE) > { "tee", &trusted_key_tee_ops }, > #endif > }; > -- > git-series 0.9.1 Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx> /Jarkko
