Merge pull request #373 from danielinux/universal_keystore

Improvement to keystore and key management tools

Author: dgarske

.github/workflows/test-keytools.yml

@@ -144,3 +144,97 @@ jobs:
       - name: Generate final signed binary
         run: |
           ./tools/keytools/sign --rsa2048 --sha256 --manual-sign test-app/image.elf public-key.der 1 test-app/image_v1.sig
+
+      # SIGN tool options
+      - name: make clean
+        run: |
+          make distclean
+
+      - name: Select config
+        run: |
+          cp config/examples/sim.config .config && make include/target.h
+
+      - name: Build tools
+        run: |
+          make -C tools/keytools && make -C tools/bin-assemble
+
+      - name: Build wolfboot
+        run: |
+          make SIGN=ECC256 HASH=SHA256
+
+      - name: Sign without timestamp
+        run: |
+          ./tools/keytools/sign --ecc256 --sha256 --no-ts test-app/image.elf wolfboot_signing_private_key.der 2
+
+     # TODO: requires hexdump
+     #- name: Check that timestamp is not included in the signed image
+     #  run: |
+     #  ! (hexdump -C -n 256 test-app/image_v3_signed.bin |grep "02 00 08 00")
+
+     # Universal keystore
+      - name: make clean
+        run: |
+          make distclean
+
+      - name: Select config
+        run: |
+          cp config/examples/sim.config .config && make include/target.h
+
+      - name: Build tools
+        run: |
+          make -C tools/keytools && make -C tools/bin-assemble
+
+      - name: Generate external RSA2048 key
+        run: |
+            openssl genrsa -out private-key.pem 2048
+
+      - name: Convert to DER
+        run: |
+          openssl rsa -in private-key.pem -inform PEM -out private-key.der -outform DER
+
+      - name: Export external public key
+        run: |
+          openssl rsa -inform DER -outform DER -in private-key.der -out public-rsa2048-key.der -pubout
+
+      - name: Add different keys to the keystore (two generated ECC with different curves, one imported RSA)
+        run: |
+          ./tools/keytools/keygen --rsa2048 -i public-rsa2048-key.der --ecc256 -g wolfboot_signing_private_key.der --ecc384 -g ecc384-priv-key.der
+
+      - name: Build wolfboot with universal keystore
+        run: |
+          make SIGN=ECC256 HASH=SHA256 WOLFBOOT_UNIVERSAL_KEYSTORE=1
+
+    # keygen option: masks
+      - name: make clean
+        run: |
+          make distclean
+
+      - name: Select config
+        run: |
+          cp config/examples/sim.config .config && make include/target.h
+
+      - name: Build tools
+        run: |
+          make -C tools/keytools && make -C tools/bin-assemble
+
+      - name: Run keygen with no specific mask
+        run: |
+          ./tools/keytools/keygen --ecc256 -g wolfboot_signing_private_key.der | grep "mask" | grep "ffffffff"
+
+      - name: Delete generated key
+        run: |
+          rm -f wolfboot_signing_private_key.der
+
+      - name: Run keygen with --id 0
+        run: |
+          ./tools/keytools/keygen --id 0 --ecc256 -g wolfboot_signing_private_key.der | grep "mask" | grep "00000001"
+
+      - name: Delete generated key
+        run: |
+          rm -f wolfboot_signing_private_key.der
+
+      - name: Run keygen with test id set
+        run: |
+          ./tools/keytools/keygen --id 1,3,5,10,11,13,14 --ecc256 -g wolfboot_signing_private_key.der | grep "mask" | grep "00006c2a"
+
+

.gitignore

@@ -105,6 +105,7 @@ tools/tpm/pcr_read
 tools/tpm/pcr_reset
 tools/tpm/pcr_extend
 tools/tpm/policy_create
+tools/tpm/policy_sign
 config/*.ld
 
 # Generated confiuguration file

docs/keystore.md

@@ -117,24 +117,48 @@ By default, when a new keystore is created, the permissions mask is set
 to `KEY_VERIFY_ALL`, which means that the key can be used to verify a firmware
 targeting any partition id.
 
-To restrict the permissions for single keys, it would be sufficient to change the value
-of their `part_id_mask` attributes.
-
 The `part_id_mask` value is a bitmask, where each bit represent a different partition.
 The bit '0' is reserved for wolfBoot self-update, while typically the main firmware partition
 is associated to id 1, so it requires a key with the bit '1' set. In other words, signing a
 partition with `--id 3` would require turning on bit '3' in the mask, i.e. adding (1U << 3) to it.
 
-Beside `KEY_VERIFY_ALL`, pre-defined mask values can also be used here:
+To restrict the permissions for single keys, it would be sufficient to change the value
+of each key `part_id_mask`. This is done via the `--id` command line option for keygen.
+Each generated or imported key can be associated with a number of partition by passing the
+partition IDs in a comma-separated list, e.g.:
+
+```
+keygen --ecc256 -g generic.key --id 1,2,3 -g restricted.key
+```
 
-- `KEY_VERIFY_APP_ONLY` only verifies the main application, with partition id 1
-- `KEY_VERIFY_SELF_ONLY` this key can only be used to authenticate wolfBoot self-updates (id = 0)
-- `KEY_VERIFY_ONLY_ID(N)` macro that can be used to restrict the usage of the key to a specific partition id `N`
+Generates two keypairs, `generic.key` and `restricted.key`. The former assumes the
+default mask `KEY_VERIFY_ALL`, which makes it possible to use it to authenticate any
+of the system components. The latter instead, will carry a mask with only the bits
+'1', '2', and '3' set (mask = b00001110 =0x000e), allowing the usage only with the assigned
+partition IDs.
 
 
 ### Importing public keys
 
-Work in progress.
+The "-i" option is used to import existing public keys into the keyvault. The usage is identical to the '-g' option, except that
+the file provided must exist and contain a valid public key of the given algorithm and key size.
+
+### Generating and importing keys of different types
+
+By default, wolfBoot hardcodes the type of key used for all the signature verification operations into the keystore format.
+
+Alternatively, wolfBoot can be compiled with the option `WOLFBOOT_UNIVERSAL_KEYSTORE=1`, which disables the check at compile
+time and allows adding keys of different types to the keystore. For example, if we want to create two keypairs with different ECC curves,
+and additionally store a pre-existing RSA2048 public key file `rsa-pub.der`, we could run the following:
+
+`keygen --ecc256 -g a.key  --ecc384 -g b.key --rsa2048 -i rsa-pub.der`
+
+The command above generates a keystore with three public keys that are accessible by the bootloader at runtime.
+
+Please note that by default wolfBoot does not include any public key algorithm implementations besides the one
+selected via the option `SIGN=`, so usually this feature is reserved to specific use cases where other policies or components
+in the chain-of-trust require to store different key types for different purposes.
+
 
 ## Using KeyStore with external Key Vaults
 
@@ -152,7 +176,7 @@ The API consists of a few functions described below.
 
 Returns the number of slots in the keystore. At least one slot
 should be populated if you want to authenticate your firmware today.
-The interface assumes that the slots are numbered sequentially, from zero to 
+The interface assumes that the slots are numbered sequentially, from zero to
 `keystore_num_pubkeys() - 1`. Accessing those slots through this API should always
  return a valid public key.
 
@@ -174,5 +198,3 @@ public key associated to the slot `id`.
 `uint32_t keystore_get_mask(int id)`
 
 Returns the permissions mask, as a 32-bit word, for the public key stored in the slot `id`.
-
-

include/wolfboot/wolfboot.h

@@ -175,35 +175,53 @@ extern "C" {
  /* Authentication configuration */
  #if defined(WOLFBOOT_NO_SIGN)
  #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_NONE
- #   define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_NONE
+ #   ifndef WOLFBOOT_UNIVERSAL_KEYSTORE
+ #     define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_NONE
+ #   endif
  #elif defined(WOLFBOOT_SIGN_ED25519)
  #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_ED25519
- #   define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_ED25519
+ #   ifndef WOLFBOOT_UNIVERSAL_KEYSTORE
+ #     define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_ED25519
+ #   endif
  #elif defined(WOLFBOOT_SIGN_ED448)
  #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_ED448
- #   define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_ED448
+ #   ifndef WOLFBOOT_UNIVERSAL_KEYSTORE
+ #     define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_ED448
+ #   endif
  #elif defined(WOLFBOOT_SIGN_ECC256)
  #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_ECC256
- #   define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_ECC256
+ #   ifndef WOLFBOOT_UNIVERSAL_KEYSTORE
+ #     define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_ECC256
+ #   endif
  #elif defined(WOLFBOOT_SIGN_ECC384)
  #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_ECC384
- #   define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_ECC384
+ #   ifndef WOLFBOOT_UNIVERSAL_KEYSTORE
+ #     define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_ECC384
+ #   endif
  #elif defined(WOLFBOOT_SIGN_ECC521)
  #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_ECC521
  #   error "ECC521 curves not yet supported in this version of wolfBoot. " \
            "Please select a valid SIGN= option."
  #elif defined(WOLFBOOT_SIGN_RSA2048)
  #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_RSA2048
- #   define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_RSA2048
+ #   ifndef WOLFBOOT_UNIVERSAL_KEYSTORE
+ #     define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_RSA2048
+ #   endif
  #elif defined(WOLFBOOT_SIGN_RSA3072)
  #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_RSA3072
- #   define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_RSA3072
+ #   ifndef WOLFBOOT_UNIVERSAL_KEYSTORE
+ #     define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_RSA3072
+ #   endif
  #elif defined(WOLFBOOT_SIGN_RSA4096)
  #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_RSA4096
- #   define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_RSA4096
+ #   ifndef WOLFBOOT_UNIVERSAL_KEYSTORE
+ #     define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_RSA4096
+ #   endif
  #elif defined(WOLFBOOT_SIGN_LMS)
  #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_LMS
- #   define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_LMS
+ #   ifndef WOLFBOOT_UNIVERSAL_KEYSTORE
+ #     define KEYSTORE_PUBKEY_SIZE KEYSTORE_PUBKEY_SIZE_LMS
+ #   endif
  #else
  #   error "No valid authentication mechanism selected. " \
            "Please select a valid SIGN= option."

options.mk

@@ -657,6 +657,10 @@ ifeq ($(64BIT),1)
   CFLAGS+=-DWOLFBOOT_64BIT
 endif
 
+ifeq ($(WOLFBOOT_UNIVERSAL_KEYSTORE),1)
+  CFLAGS+=-DWOLFBOOT_UNIVERSAL_KEYSTORE
+endif
+
 ifeq ($(DISK_LOCK),1)
   CFLAGS+=-DWOLFBOOT_ATA_DISK_LOCK
   ifneq ($(DISK_LOCK_PASSWORD),)

tools/config.mk

@@ -53,6 +53,7 @@ ifeq ($(ARCH),)
   MEASURED_BOOT?=0
   WOLFBOOT_TPM_SEAL?=0
   WOLFBOOT_TPM_KEYSTORE?=0
+  WOLFBOOT_UNIVERSAL_KEYSTORE?=0
   TZEN?=0
   WOLFCRYPT_TZ?=0
   WOLFCRYPT_TZ_PKCS11?=0
@@ -91,4 +92,5 @@ CONFIG_VARS:= ARCH TARGET SIGN HASH MCUXSDK MCUXPRESSO MCUXPRESSO_CPU MCUXPRESSO
 	WOLFBOOT_HUGE_STACK FORCE_32BIT\
 	ENCRYPT_WITH_CHACHA ENCRYPT_WITH_AES128 ENCRYPT_WITH_AES256 ARMORED \
 	LMS_LEVELS LMS_HEIGHT LMS_WINTERNITZ \
+	WOLFBOOT_UNIVERSAL_KEYSTORE \
 	ELF