@@ -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
@@ -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
new file mode 100644
@@ -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
@@ -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
@@ -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
};
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@linaro.org> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Tested-By: Andreas Rammhold <andreas@rammhold.de> Tested-By: Tim Harvey <tharvey@gateworks.com> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de> --- v4 -> v5: - collected Jarkko's Reviewed-by 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@pengutronix.de/ [2]: https://lore.kernel.org/linux-integrity/20210719091335.vwfebcpkf4pag3wm@wrt/T/#t To: Jarkko Sakkinen <jarkko@kernel.org> To: James Morris <jmorris@namei.org> To: "Serge E. Hallyn" <serge@hallyn.com> To: James Bottomley <jejb@linux.ibm.com> To: Mimi Zohar <zohar@linux.ibm.com> To: Sumit Garg <sumit.garg@linaro.org> To: David Howells <dhowells@redhat.com> To: Herbert Xu <herbert@gondor.apana.org.au> To: "David S. Miller" <davem@davemloft.net> Cc: David Gstir <david@sigma-star.at> Cc: Richard Weinberger <richard@nod.at> Cc: Tim Harvey <tharvey@gateworks.com> Cc: Matthias Schiffer <matthias.schiffer@ew.tq-group.com> Cc: Pankaj Gupta <pankaj.gupta@nxp.com> Cc: keyrings@vger.kernel.org Cc: linux-crypto@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-security-module@vger.kernel.org Cc: linux-integrity@vger.kernel.org --- 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