Merge tag 'tpmdd-next-v5.13' of git://git.kernel.org/pub/scm/linux/ke…

…rnel/git/jarkko/linux-tpmdd

Pull tpm updates from Jarkko Sakkinen:
 "New features:

   - ARM TEE backend for kernel trusted keys to complete the existing
     TPM backend

   - ASN.1 format for TPM2 trusted keys to make them interact with the
     user space stack, such as OpenConnect VPN

  Other than that, a bunch of bug fixes"

* tag 'tpmdd-next-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd:
  KEYS: trusted: Fix missing null return from kzalloc call
  char: tpm: fix error return code in tpm_cr50_i2c_tis_recv()
  MAINTAINERS: Add entry for TEE based Trusted Keys
  doc: trusted-encrypted: updates with TEE as a new trust source
  KEYS: trusted: Introduce TEE based Trusted Keys
  KEYS: trusted: Add generic trusted keys framework
  security: keys: trusted: Make sealed key properly interoperable
  security: keys: trusted: use ASN.1 TPM2 key format for the blobs
  security: keys: trusted: fix TPM2 authorizations
  oid_registry: Add TCG defined OIDS for TPM keys
  lib: Add ASN.1 encoder
  tpm: vtpm_proxy: Avoid reading host log when using a virtual device
  tpm: acpi: Check eventlog signature before using it
  tpm: efi: Use local variable for calculating final log size

Documentation/admin-guide/kernel-parameters.txt

@@ -5462,6 +5462,18 @@
 			See Documentation/admin-guide/mm/transhuge.rst
 			for more details.
 
+	trusted.source=	[KEYS]
+			Format: <string>
+			This parameter identifies the trust source as a backend
+			for trusted keys implementation. Supported trust
+			sources:
+			- "tpm"
+			- "tee"
+			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
+			successfully during iteration.
+
 	tsc=		Disable clocksource stability checks for TSC.
 			Format: <string>
 			[x86] reliable: mark tsc clocksource as reliable, this

Documentation/security/keys/trusted-encrypted.rst

@@ -6,30 +6,127 @@ Trusted and Encrypted Keys are two new key types added to the existing kernel
 key ring service.  Both of these new types are variable length symmetric keys,
 and in both cases all keys are created in the kernel, and user space sees,
 stores, and loads only encrypted blobs.  Trusted Keys require the availability
-of a Trusted Platform Module (TPM) chip for greater security, while Encrypted
-Keys can be used on any system.  All user level blobs, are displayed and loaded
-in hex ascii for convenience, and are integrity verified.
+of a Trust Source for greater security, while Encrypted Keys can be used on any
+system. All user level blobs, are displayed and loaded in hex ASCII for
+convenience, and are integrity verified.
 
-Trusted Keys use a TPM both to generate and to seal the keys.  Keys are sealed
-under a 2048 bit RSA key in the TPM, and optionally sealed to specified PCR
-(integrity measurement) values, and only unsealed by the TPM, if PCRs and blob
-integrity verifications match.  A loaded Trusted Key can be updated with new
-(future) PCR values, so keys are easily migrated to new pcr values, such as
-when the kernel and initramfs are updated.  The same key can have many saved
-blobs under different PCR values, so multiple boots are easily supported.
 
-TPM 1.2
--------
+Trust Source
+============
 
-By default, trusted keys are sealed under the SRK, which has the default
-authorization value (20 zeros).  This can be set at takeownership time with the
-trouser's utility: "tpm_takeownership -u -z".
+A trust source provides the source of security for Trusted Keys.  This
+section lists currently supported trust sources, along with their security
+considerations.  Whether or not a trust source is sufficiently safe depends
+on the strength and correctness of its implementation, as well as the threat
+environment for a specific use case.  Since the kernel doesn't know what the
+environment is, and there is no metric of trust, it is dependent on the
+consumer of the Trusted Keys to determine if the trust source is sufficiently
+safe.
 
-TPM 2.0
--------
+  *  Root of trust for storage
 
-The user must first create a storage key and make it persistent, so the key is
-available after reboot. This can be done using the following commands.
+     (1) TPM (Trusted Platform Module: hardware device)
+
+         Rooted to Storage Root Key (SRK) which never leaves the TPM that
+         provides crypto operation to establish root of trust for storage.
+
+     (2) TEE (Trusted Execution Environment: OP-TEE based on Arm TrustZone)
+
+         Rooted to Hardware Unique Key (HUK) which is generally burnt in on-chip
+         fuses and is accessible to TEE only.
+
+  *  Execution isolation
+
+     (1) TPM
+
+         Fixed set of operations running in isolated execution environment.
+
+     (2) TEE
+
+         Customizable set of operations running in isolated execution
+         environment verified via Secure/Trusted boot process.
+
+  * Optional binding to platform integrity state
+
+     (1) TPM
+
+         Keys can be optionally sealed to specified PCR (integrity measurement)
+         values, and only unsealed by the TPM, if PCRs and blob integrity
+         verifications match. A loaded Trusted Key can be updated with new
+         (future) PCR values, so keys are easily migrated to new PCR values,
+         such as when the kernel and initramfs are updated. The same key can
+         have many saved blobs under different PCR values, so multiple boots are
+         easily supported.
+
+     (2) TEE
+
+         Relies on Secure/Trusted boot process for platform integrity. It can
+         be extended with TEE based measured boot process.
+
+  *  Interfaces and APIs
+
+     (1) TPM
+
+         TPMs have well-documented, standardized interfaces and APIs.
+
+     (2) TEE
+
+         TEEs have well-documented, standardized client interface and APIs. For
+         more details refer to ``Documentation/staging/tee.rst``.
+
+
+  *  Threat model
+
+     The strength and appropriateness of a particular TPM or TEE for a given
+     purpose must be assessed when using them to protect security-relevant data.
+
+
+Key Generation
+==============
+
+Trusted Keys
+------------
+
+New keys are created from random numbers generated in the trust source. They
+are encrypted/decrypted using a child key in the storage key hierarchy.
+Encryption and decryption of the child key must be protected by a strong
+access control policy within the trust source.
+
+  *  TPM (hardware device) based RNG
+
+     Strength of random numbers may vary from one device manufacturer to
+     another.
+
+  *  TEE (OP-TEE based on Arm TrustZone) based RNG
+
+     RNG is customizable as per platform needs. It can either be direct output
+     from platform specific hardware RNG or a software based Fortuna CSPRNG
+     which can be seeded via multiple entropy sources.
+
+Encrypted Keys
+--------------
+
+Encrypted keys do not depend on a trust source, and are faster, as they use AES
+for encryption/decryption. New keys are created from kernel-generated random
+numbers, and are encrypted/decrypted using a specified ‘master’ key. The
+‘master’ key can either be a trusted-key or user-key type. The main disadvantage
+of encrypted keys is that if they are not rooted in a trusted key, they are only
+as secure as the user key encrypting them. The master user key should therefore
+be loaded in as secure a way as possible, preferably early in boot.
+
+
+Usage
+=====
+
+Trusted Keys usage: TPM
+-----------------------
+
+TPM 1.2: By default, trusted keys are sealed under the SRK, which has the
+default authorization value (20 bytes of 0s).  This can be set at takeownership
+time with the TrouSerS utility: "tpm_takeownership -u -z".
+
+TPM 2.0: The user must first create a storage key and make it persistent, so the
+key is available after reboot. This can be done using the following commands.
 
 With the IBM TSS 2 stack::
 
@@ -78,14 +175,21 @@ TPM_STORED_DATA format.  The key length for new keys are always in bytes.
 Trusted Keys can be 32 - 128 bytes (256 - 1024 bits), the upper limit is to fit
 within the 2048 bit SRK (RSA) keylength, with all necessary structure/padding.
 
-Encrypted keys do not depend on a TPM, and are faster, as they use AES for
-encryption/decryption.  New keys are created from kernel generated random
-numbers, and are encrypted/decrypted using a specified 'master' key.  The
-'master' key can either be a trusted-key or user-key type.  The main
-disadvantage of encrypted keys is that if they are not rooted in a trusted key,
-they are only as secure as the user key encrypting them.  The master user key
-should therefore be loaded in as secure a way as possible, preferably early in
-boot.
+Trusted Keys usage: TEE
+-----------------------
+
+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 TEE 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
+--------------------
 
 The decrypted portion of encrypted keys can contain either a simple symmetric
 key or a more complex structure. The format of the more complex structure is
@@ -103,8 +207,8 @@ Where::
 	format:= 'default | ecryptfs | enc32'
 	key-type:= 'trusted' | 'user'
 
-
-Examples of trusted and encrypted key usage:
+Examples of trusted and encrypted key usage
+-------------------------------------------
 
 Create and save a trusted key named "kmk" of length 32 bytes.
 
@@ -150,7 +254,7 @@ Load a trusted key from the saved blob::
     f1f8fff03ad0acb083725535636addb08d73dedb9832da198081e5deae84bfaf0409c22b
     e4a8aea2b607ec96931e6f4d4fe563ba
 
-Reseal a trusted key under new pcr values::
+Reseal (TPM specific) a trusted key under new PCR values::
 
     $ keyctl update 268728824 "update pcrinfo=`cat pcr.blob`"
     $ keyctl print 268728824
@@ -164,11 +268,12 @@ Reseal a trusted key under new pcr values::
     7ef6a24defe4846104209bf0c3eced7fa1a672ed5b125fc9d8cd88b476a658a4434644ef
     df8ae9a178e9f83ba9f08d10fa47e4226b98b0702f06b3b8
 
+
 The initial consumer of trusted keys is EVM, which at boot time needs a high
-quality symmetric key for HMAC protection of file metadata.  The use of a
+quality symmetric key for HMAC protection of file metadata. The use of a
 trusted key provides strong guarantees that the EVM key has not been
-compromised by a user level problem, and when sealed to specific boot PCR
-values, protects against boot and offline attacks.  Create and save an
+compromised by a user level problem, and when sealed to a platform integrity
+state, protects against boot and offline attacks. Create and save an
 encrypted key "evm" using the above trusted key "kmk":
 
 option 1: omitting 'format'::
@@ -207,3 +312,61 @@ about the usage can be found in the file
 Another new format 'enc32' has been defined in order to support encrypted keys
 with payload size of 32 bytes. This will initially be used for nvdimm security
 but may expand to other usages that require 32 bytes payload.
+
+
+TPM 2.0 ASN.1 Key Format
+------------------------
+
+The TPM 2.0 ASN.1 key format is designed to be easily recognisable,
+even in binary form (fixing a problem we had with the TPM 1.2 ASN.1
+format) and to be extensible for additions like importable keys and
+policy::
+
+    TPMKey ::= SEQUENCE {
+        type		OBJECT IDENTIFIER
+        emptyAuth	[0] EXPLICIT BOOLEAN OPTIONAL
+        parent		INTEGER
+        pubkey		OCTET STRING
+        privkey		OCTET STRING
+    }
+
+type is what distinguishes the key even in binary form since the OID
+is provided by the TCG to be unique and thus forms a recognizable
+binary pattern at offset 3 in the key.  The OIDs currently made
+available are::
+
+    2.23.133.10.1.3 TPM Loadable key.  This is an asymmetric key (Usually
+                    RSA2048 or Elliptic Curve) which can be imported by a
+                    TPM2_Load() operation.
+
+    2.23.133.10.1.4 TPM Importable Key.  This is an asymmetric key (Usually
+                    RSA2048 or Elliptic Curve) which can be imported by a
+                    TPM2_Import() operation.
+
+    2.23.133.10.1.5 TPM Sealed Data.  This is a set of data (up to 128
+                    bytes) which is sealed by the TPM.  It usually
+                    represents a symmetric key and must be unsealed before
+                    use.
+
+The trusted key code only uses the TPM Sealed Data OID.
+
+emptyAuth is true if the key has well known authorization "".  If it
+is false or not present, the key requires an explicit authorization
+phrase.  This is used by most user space consumers to decide whether
+to prompt for a password.
+
+parent represents the parent key handle, either in the 0x81 MSO space,
+like 0x81000001 for the RSA primary storage key.  Userspace programmes
+also support specifying the primary handle in the 0x40 MSO space.  If
+this happens the Elliptic Curve variant of the primary key using the
+TCG defined template will be generated on the fly into a volatile
+object and used as the parent.  The current kernel code only supports
+the 0x81 MSO form.
+
+pubkey is the binary representation of TPM2B_PRIVATE excluding the
+initial TPM2B header, which can be reconstructed from the ASN.1 octet
+string length.
+
+privkey is the binary representation of TPM2B_PUBLIC excluding the
+initial TPM2B header which can be reconstructed from the ASN.1 octed
+string length.

MAINTAINERS

@@ -9887,6 +9887,14 @@ F:	include/keys/trusted-type.h
 F:	include/keys/trusted_tpm.h
 F:	security/keys/trusted-keys/
 
+KEYS-TRUSTED-TEE
+M:	Sumit Garg <[email protected]>
+L:	[email protected]
+L:	[email protected]
+S:	Supported
+F:	include/keys/trusted_tee.h
+F:	security/keys/trusted-keys/trusted_tee.c
+
 KEYS/KEYRINGS
 M:	David Howells <[email protected]>
 M:	Jarkko Sakkinen <[email protected]>

drivers/char/tpm/eventlog/acpi.c

@@ -41,6 +41,27 @@ struct acpi_tcpa {
 	};
 };
 
+/* Check that the given log is indeed a TPM2 log. */
+static bool tpm_is_tpm2_log(void *bios_event_log, u64 len)
+{
+	struct tcg_efi_specid_event_head *efispecid;
+	struct tcg_pcr_event *event_header;
+	int n;
+
+	if (len < sizeof(*event_header))
+		return false;
+	len -= sizeof(*event_header);
+	event_header = bios_event_log;
+
+	if (len < sizeof(*efispecid))
+		return false;
+	efispecid = (struct tcg_efi_specid_event_head *)event_header->event;
+
+	n = memcmp(efispecid->signature, TCG_SPECID_SIG,
+		   sizeof(TCG_SPECID_SIG));
+	return n == 0;
+}
+
 /* read binary bios log */
 int tpm_read_log_acpi(struct tpm_chip *chip)
 {
@@ -52,6 +73,7 @@ int tpm_read_log_acpi(struct tpm_chip *chip)
 	struct acpi_table_tpm2 *tbl;
 	struct acpi_tpm2_phy *tpm2_phy;
 	int format;
+	int ret;
 
 	log = &chip->log;
 
@@ -112,18 +134,27 @@ int tpm_read_log_acpi(struct tpm_chip *chip)
 
 	log->bios_event_log_end = log->bios_event_log + len;
 
+	ret = -EIO;
 	virt = acpi_os_map_iomem(start, len);
 	if (!virt)
 		goto err;
 
 	memcpy_fromio(log->bios_event_log, virt, len);
 
 	acpi_os_unmap_iomem(virt, len);
+
+	if (chip->flags & TPM_CHIP_FLAG_TPM2 &&
+	    !tpm_is_tpm2_log(log->bios_event_log, len)) {
+		/* try EFI log next */
+		ret = -ENODEV;
+		goto err;
+	}
+
 	return format;
 
 err:
 	kfree(log->bios_event_log);
 	log->bios_event_log = NULL;
-	return -EIO;
+	return ret;
 
 }

drivers/char/tpm/eventlog/common.c

@@ -107,6 +107,9 @@ void tpm_bios_log_setup(struct tpm_chip *chip)
 	int log_version;
 	int rc = 0;
 
+	if (chip->flags & TPM_CHIP_FLAG_VIRTUAL)
+		return;
+
 	rc = tpm_read_log(chip);
 	if (rc < 0)
 		return;