[4/4] KEYS: trusted: Introduce support for NXP CAAM-based trusted keys

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 0267ead88902..43010cb27f17 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5729,6 +5729,7 @@ 
 			sources:
 			- "tpm"
 			- "tee"
+			- "caam"
 			If not specified then it defaults to iterating through
 			the trust source list starting with TPM and assigns the
 			first trust source as a backend which is initialized
diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst
index 1d4b4b8f12f0..ad66573ca6fd 100644
--- a/Documentation/security/keys/trusted-encrypted.rst
+++ b/Documentation/security/keys/trusted-encrypted.rst
@@ -35,6 +35,13 @@  safe.
          Rooted to Hardware Unique Key (HUK) which is generally burnt in on-chip
          fuses and is accessible to TEE only.
 
+     (3) CAAM (Cryptographic Acceleration and Assurance Module: IP on NXP SoCs)
+
+         When High Assurance Boot (HAB) is enabled and the CAAM is in secure
+         mode, trust is rooted to the OTPMK, a never-disclosed 256-bit key
+         randomly generated and fused into each SoC at manufacturing time.
+         Otherwise, a common fixed test key is used instead.
+
   *  Execution isolation
 
      (1) TPM
@@ -46,6 +53,10 @@  safe.
          Customizable set of operations running in isolated execution
          environment verified via Secure/Trusted boot process.
 
+     (3) CAAM
+
+         Fixed set of operations running in isolated execution environment.
+
   * Optional binding to platform integrity state
 
      (1) TPM
@@ -63,6 +74,11 @@  safe.
          Relies on Secure/Trusted boot process for platform integrity. It can
          be extended with TEE based measured boot process.
 
+     (3) CAAM
+
+         Relies on the High Assurance Boot (HAB) mechanism of NXP SoCs
+         for platform integrity.
+
   *  Interfaces and APIs
 
      (1) TPM
@@ -74,10 +90,13 @@  safe.
          TEEs have well-documented, standardized client interface and APIs. For
          more details refer to ``Documentation/staging/tee.rst``.
 
+     (3) CAAM
+
+         Interface is specific to silicon vendor.
 
   *  Threat model
 
-     The strength and appropriateness of a particular TPM or TEE for a given
+     The strength and appropriateness of a particular trust source for a given
      purpose must be assessed when using them to protect security-relevant data.
 
 
@@ -104,8 +123,14 @@  selected trust source:
      from platform specific hardware RNG or a software based Fortuna CSPRNG
      which can be seeded via multiple entropy sources.
 
+  *  CAAM: Kernel RNG
+
+     The normal kernel random number generator is used. To seed it from the
+     CAAM HWRNG, enable CRYPTO_DEV_FSL_CAAM_RNG_API and ensure the device
+     can be probed.
+
 Optionally, users may specify ``trusted.kernel_rng=1`` on the kernel
-command-line to override the used RNG with the kernel's random number pool.
+command-line to force use of the kernel's random number pool.
 
 Encrypted Keys
 --------------
@@ -192,6 +217,19 @@  Usage::
 specific to TEE device implementation.  The key length for new keys is always
 in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits).
 
+Trusted Keys usage: CAAM
+------------------------
+
+Usage::
+
+    keyctl add trusted name "new keylen" ring
+    keyctl add trusted name "load hex_blob" ring
+    keyctl print keyid
+
+"keyctl print" returns an ASCII hex copy of the sealed key, which is in format
+specific to CAAM device implementation.  The key length for new keys is always
+in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits).
+
 Encrypted Keys usage
 --------------------
 
diff --git a/MAINTAINERS b/MAINTAINERS
index 6c8be735cc91..aa654e69075d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10265,6 +10265,15 @@  S:	Supported
 F:	include/keys/trusted_tee.h
 F:	security/keys/trusted-keys/trusted_tee.c
 
+KEYS-TRUSTED-CAAM
+M:	Ahmad Fatoum <a.fatoum@pengutronix.de>
+R:	Pengutronix Kernel Team <kernel@pengutronix.de>
+L:	linux-integrity@vger.kernel.org
+L:	keyrings@vger.kernel.org
+S:	Supported
+F:	include/keys/trusted_caam.h
+F:	security/keys/trusted-keys/trusted_caam.c
+
 KEYS/KEYRINGS
 M:	David Howells <dhowells@redhat.com>
 M:	Jarkko Sakkinen <jarkko@kernel.org>
diff --git a/include/keys/trusted_caam.h b/include/keys/trusted_caam.h
new file mode 100644
index 000000000000..2fba0996b0b0
--- /dev/null
+++ b/include/keys/trusted_caam.h
@@ -0,0 +1,11 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2021 Pengutronix, Ahmad Fatoum <kernel@pengutronix.de>
+ */
+
+#ifndef __CAAM_TRUSTED_KEY_H
+#define __CAAM_TRUSTED_KEY_H
+
+extern struct trusted_key_ops caam_trusted_key_ops;
+
+#endif
diff --git a/security/keys/trusted-keys/Kconfig b/security/keys/trusted-keys/Kconfig
index c163cfeedff6..fac80117ef46 100644
--- a/security/keys/trusted-keys/Kconfig
+++ b/security/keys/trusted-keys/Kconfig
@@ -24,6 +24,15 @@  config TRUSTED_KEYS_TEE
 	  Enable use of the Trusted Execution Environment (TEE) as trusted
 	  key backend.
 
-if !TRUSTED_KEYS_TPM && !TRUSTED_KEYS_TEE
+config TRUSTED_KEYS_CAAM
+	bool "CAAM-based trusted keys"
+	depends on CRYPTO_DEV_FSL_CAAM_JR >= TRUSTED_KEYS
+	select CRYPTO_DEV_FSL_CAAM_BLOB_GEN
+	default y
+	help
+	  Enable use of NXP's Cryptographic Accelerator and Assurance Module
+	  (CAAM) as trusted key backend.
+
+if !TRUSTED_KEYS_TPM && !TRUSTED_KEYS_TEE && !TRUSTED_KEYS_CAAM
 comment "No trust source selected!"
 endif
diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile
index 2e2371eae4d5..735aa0bc08ef 100644
--- a/security/keys/trusted-keys/Makefile
+++ b/security/keys/trusted-keys/Makefile
@@ -12,3 +12,5 @@  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_TRUSTED_KEYS_CAAM) += trusted_caam.o
diff --git a/security/keys/trusted-keys/trusted_caam.c b/security/keys/trusted-keys/trusted_caam.c
new file mode 100644
index 000000000000..01adfd18adda
--- /dev/null
+++ b/security/keys/trusted-keys/trusted_caam.c
@@ -0,0 +1,74 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021 Pengutronix, Ahmad Fatoum <kernel@pengutronix.de>
+ */
+
+#include <keys/trusted_caam.h>
+#include <keys/trusted-type.h>
+#include <linux/build_bug.h>
+#include <linux/key-type.h>
+#include <soc/fsl/caam-blob.h>
+
+static struct caam_blob_priv *blobifier;
+
+#define KEYMOD "kernel:trusted"
+
+static_assert(MAX_KEY_SIZE + CAAM_BLOB_OVERHEAD <= CAAM_BLOB_MAX_LEN);
+static_assert(MAX_BLOB_SIZE <= CAAM_BLOB_MAX_LEN);
+
+static int trusted_caam_seal(struct trusted_key_payload *p, char *datablob)
+{
+	int length = p->key_len + CAAM_BLOB_OVERHEAD;
+	int ret;
+
+	ret = caam_encap_blob(blobifier, KEYMOD, p->key, p->blob, length);
+	if (ret)
+		return ret;
+
+	p->blob_len = length;
+	return 0;
+}
+
+static int trusted_caam_unseal(struct trusted_key_payload *p, char *datablob)
+{
+	int length = p->blob_len;
+	int ret;
+
+	ret = caam_decap_blob(blobifier, KEYMOD, p->blob, p->key, length);
+	if (ret)
+		return ret;
+
+	p->key_len = length - CAAM_BLOB_OVERHEAD;
+	return 0;
+}
+
+static int trusted_caam_init(void)
+{
+	int ret;
+
+	blobifier = caam_blob_gen_init();
+	if (IS_ERR(blobifier)) {
+		pr_err("Job Ring Device allocation for transform failed\n");
+		return PTR_ERR(blobifier);
+	}
+
+	ret = register_key_type(&key_type_trusted);
+	if (ret)
+		caam_blob_gen_exit(blobifier);
+
+	return ret;
+}
+
+static void trusted_caam_exit(void)
+{
+	unregister_key_type(&key_type_trusted);
+	caam_blob_gen_exit(blobifier);
+}
+
+struct trusted_key_ops caam_trusted_key_ops = {
+	.migratable = 0, /* non-migratable */
+	.init = trusted_caam_init,
+	.seal = trusted_caam_seal,
+	.unseal = trusted_caam_unseal,
+	.exit = trusted_caam_exit,
+};
diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
index d2b7626cde8b..305e44651180 100644
--- a/security/keys/trusted-keys/trusted_core.c
+++ b/security/keys/trusted-keys/trusted_core.c
@@ -9,6 +9,7 @@ 
 #include <keys/user-type.h>
 #include <keys/trusted-type.h>
 #include <keys/trusted_tee.h>
+#include <keys/trusted_caam.h>
 #include <keys/trusted_tpm.h>
 #include <linux/capability.h>
 #include <linux/err.h>
@@ -29,7 +30,7 @@  MODULE_PARM_DESC(kernel_rng, "Generate key material from kernel RNG");
 
 static char *trusted_key_source;
 module_param_named(source, trusted_key_source, charp, 0);
-MODULE_PARM_DESC(source, "Select trusted keys source (tpm or tee)");
+MODULE_PARM_DESC(source, "Select trusted keys source (tpm, tee or caam)");
 
 static const struct trusted_key_source trusted_key_sources[] = {
 #if defined(CONFIG_TRUSTED_KEYS_TPM)
@@ -38,6 +39,9 @@  static const struct trusted_key_source trusted_key_sources[] = {
 #if defined(CONFIG_TRUSTED_KEYS_TEE)
 	{ "tee", &trusted_key_tee_ops },
 #endif
+#if defined(CONFIG_TRUSTED_KEYS_CAAM)
+	{ "caam", &caam_trusted_key_ops },
+#endif
 };
 
 DEFINE_STATIC_CALL_NULL(trusted_key_init, *trusted_key_sources[0].ops->init);