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 Kconfig symbols:
TRUSTED_KEYS_TPM and TRUSTED_KEYS_TEE with the appropriate
dependencies.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
To: James Bottomley <jejb@xxxxxxxxxxxxx>
To: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
To: Mimi Zohar <zohar@xxxxxxxxxxxxx>
To: David Howells <dhowells@xxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Cc: Eric Biggers <ebiggers@xxxxxxxxxx>
Cc: "Serge E. Hallyn" <serge@xxxxxxxxxx>
Cc: "Horia Geantă" <horia.geanta@xxxxxxx>
Cc: Aymen Sghaier <aymen.sghaier@xxxxxxx>
Cc: Udit Agarwal <udit.agarwal@xxxxxxx>
Cc: Jan Luebbe <j.luebbe@xxxxxxxxxxxxxx>
Cc: David Gstir <david@xxxxxxxxxxxxx>
Cc: Richard Weinberger <richard@xxxxxx>
Cc: Franck LENORMAND <franck.lenormand@xxxxxxx>
Cc: Sumit Garg <sumit.garg@xxxxxxxxxx>
Cc: keyrings@xxxxxxxxxxxxxxx
Cc: linux-crypto@xxxxxxxxxxxxxxx
Cc: linux-integrity@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-security-module@xxxxxxxxxxxxxxx
---
security/keys/Kconfig | 14 ++++++-------
security/keys/trusted-keys/Kconfig | 25 ++++++++++++++++++++++++-
security/keys/trusted-keys/Makefile | 8 +++++---
security/keys/trusted-keys/trusted_core.c | 4 ++--
4 files changed, 39 insertions(+), 12 deletions(-)
create mode 100644 security/keys/trusted-keys/Kconfig
diff --git a/security/keys/Kconfig b/security/keys/Kconfig
index 64b81abd087e..6fdb953b319f 100644
--- a/security/keys/Kconfig
+++ b/security/keys/Kconfig
@@ -70,23 +70,23 @@ config BIG_KEYS
config TRUSTED_KEYS
tristate "TRUSTED KEYS"
- depends on KEYS && TCG_TPM
+ depends on KEYS
select CRYPTO
select CRYPTO_HMAC
select CRYPTO_SHA1
select CRYPTO_HASH_INFO
- select ASN1_ENCODER
- select OID_REGISTRY
- select ASN1
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..24af4aaceebf
--- /dev/null
+++ b/security/keys/trusted-keys/Kconfig
@@ -0,0 +1,25 @@
+config TRUSTED_KEYS_TPM
+ bool "TPM-based trusted keys"
+ depends on TCG_TPM >= TRUSTED_KEYS
+ default y
+ select ASN1_ENCODER
+ select OID_REGISTRY
+ select ASN1
+ help
+ Enable use of the Trusted Platform Module (TPM) as trusted key
+ backend. Trusted keys are 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..96fc6c377398 100644
--- a/security/keys/trusted-keys/Makefile
+++ b/security/keys/trusted-keys/Makefile
@@ -5,10 +5,12 @@
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_TRUSTED_KEYS_TEE) += trusted_tee.o
trusted-$(CONFIG_TEE) += trusted_tee.o
diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
index d5c891d8d353..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 defined(CONFIG_TCG_TPM)
+#if defined(CONFIG_TRUSTED_KEYS_TPM)
{ "tpm", &trusted_key_tpm_ops },
#endif
-#if defined(CONFIG_TEE)
+#if defined(CONFIG_TRUSTED_KEYS_TEE)
{ "tee", &trusted_key_tee_ops },
#endif
};
--
git-series 0.9.1
