mkimage: Add support for signing with pkcs11

Add support for signing with the pkcs11 engine. This allows FIT images to be signed with keys securely stored on a smartcard, hardware security module, etc without exposing the keys. Support for other engines can be added in the future by modifying rsa_engine_get_pub_key() and rsa_engine_get_priv_key() to construct correct key_id strings. Signed-off-by: George McCollister <george.mccollister@gmail.com>

mkimage: Add support for signing with pkcs11
Add support for signing with the pkcs11 engine. This allows FIT images to be signed with keys securely stored on a smartcard, hardware security module, etc without exposing the keys. Support for other engines can be added in the future by modifying rsa_engine_get_pub_key() and rsa_engine_get_priv_key() to construct correct key_id strings. Signed-off-by: George McCollister <george.mccollister@gmail.com>
George McCollister · Tom Rini
1 parent b1c6a54a53
Showing 7 changed files with 408 additions and 28 deletions Side-by-side Diff
doc/uImage.FIT/signature.txt
include/image.h
lib/rsa/rsa-sign.c
tools/fit_image.c
tools/image-host.c
tools/imagetool.h
tools/mkimage.c
@@ -385,6 +385,149 @@
 Test passed
  
  
+Hardware Signing with PKCS#11
+-----------------------------
+
+Securely managing private signing keys can challenging, especially when the
+keys are stored on the file system of a computer that is connected to the
+Internet. If an attacker is able to steal the key, they can sign malicious FIT
+images which will appear genuine to your devices.
+
+An alternative solution is to keep your signing key securely stored on hardware
+device like a smartcard, USB token or Hardware Security Module (HSM) and have
+them perform the signing. PKCS#11 is standard for interfacing with these crypto
+device.
+
+Requirements:
+Smartcard/USB token/HSM which can work with the pkcs11 engine
+openssl
+libp11 (provides pkcs11 engine)
+p11-kit (recommended to simplify setup)
+opensc (for smartcards and smartcard like USB devices)
+gnutls (recommended for key generation, p11tool)
+
+The following examples use the Nitrokey Pro. Instructions for other devices may vary.
+
+Notes on pkcs11 engine setup:
+
+Make sure p11-kit, opensc are installed and that p11-kit is setup to use opensc.
+/usr/share/p11-kit/modules/opensc.module should be present on your system.
+
+
+Generating Keys On the Nitrokey:
+
+$ gpg --card-edit
+
+Reader ...........: Nitrokey Nitrokey Pro (xxxxxxxx0000000000000000) 00 00
+Application ID ...: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+Version ..........: 2.1
+Manufacturer .....: ZeitControl
+Serial number ....: xxxxxxxx
+Name of cardholder: [not set]
+Language prefs ...: de
+Sex ..............: unspecified
+URL of public key : [not set]
+Login data .......: [not set]
+Signature PIN ....: forced
+Key attributes ...: rsa2048 rsa2048 rsa2048
+Max. PIN lengths .: 32 32 32
+PIN retry counter : 3 0 3
+Signature counter : 0
+Signature key ....: [none]
+Encryption key....: [none]
+Authentication key: [none]
+General key info..: [none]
+
+gpg/card> generate
+Make off-card backup of encryption key? (Y/n) n
+
+Please note that the factory settings of the PINs are
+  PIN = '123456' Admin PIN = '12345678'
+You should change them using the command --change-pin
+
+What keysize do you want for the Signature key? (2048) 4096
+The card will now be re-configured to generate a key of 4096 bits
+Note: There is no guarantee that the card supports the requested size.
+  If the key generation does not succeed, please check the
+  documentation of your card to see what sizes are allowed.
+What keysize do you want for the Encryption key? (2048) 4096
+The card will now be re-configured to generate a key of 4096 bits
+What keysize do you want for the Authentication key? (2048) 4096
+The card will now be re-configured to generate a key of 4096 bits
+Please specify how long the key should be valid.
+  0 = key does not expire
+  <n> = key expires in n days
+  <n>w = key expires in n weeks
+  <n>m = key expires in n months
+  <n>y = key expires in n years
+Key is valid for? (0)
+Key does not expire at all
+Is this correct? (y/N) y
+
+GnuPG needs to construct a user ID to identify your key.
+
+Real name: John Doe
+Email address: john.doe@email.com
+Comment:
+You selected this USER-ID:
+  "John Doe <john.doe@email.com>"
+
+Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o
+
+
+Using p11tool to get the token URL:
+
+Depending on system configuration, gpg-agent may need to be killed first.
+
+$ p11tool --provider /usr/lib/opensc-pkcs11.so --list-tokens
+Token 0:
+URL: pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29
+Label: OpenPGP card (User PIN (sig))
+Type: Hardware token
+Manufacturer: ZeitControl
+Model: PKCS#15 emulated
+Serial: 000xxxxxxxxx
+Module: (null)
+
+
+Token 1:
+URL: pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%29
+Label: OpenPGP card (User PIN)
+Type: Hardware token
+Manufacturer: ZeitControl
+Model: PKCS#15 emulated
+Serial: 000xxxxxxxxx
+Module: (null)
+
+Use the portion of the signature token URL after "pkcs11:" as the keydir argument (-k) to mkimage below.
+
+
+Use the URL of the token to list the private keys:
+
+$ p11tool --login --provider /usr/lib/opensc-pkcs11.so --list-privkeys \
+"pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29"
+Token 'OpenPGP card (User PIN (sig))' with URL 'pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29' requires user PIN
+Enter PIN:
+Object 0:
+URL: pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29;id=%01;object=Signature%20key;type=private
+Type: Private key
+Label: Signature key
+Flags: CKA_PRIVATE; CKA_NEVER_EXTRACTABLE; CKA_SENSITIVE;
+ID: 01
+
+Use the label, in this case "Signature key" as the key-name-hint in your FIT.
+
+Create the fitImage:
+$ ./tools/mkimage -f fit-image.its fitImage
+
+
+Sign the fitImage with the hardware key:
+
+$ ./tools/mkimage -F -k \
+"model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29" \
+-K u-boot.dtb -N pkcs11 -r fitImage
+
+
 Future Work
 -----------
 - Roll-back protection using a TPM is done using the tpm command. This can
@@ -965,6 +965,7 @@
  * @fit:	Pointer to the FIT format image header
  * @comment:	Comment to add to signature nodes
  * @require_keys: Mark all keys as 'required'
+ * @engine_id:	Engine to use for signing
  *
  * Adds hash values for all component images in the FIT blob.
  * Hashes are calculated for all component images which have hash subnodes
@@ -977,7 +978,8 @@
  *     libfdt error code, on failure
  */
 int fit_add_verification_data(const char *keydir, void *keydest, void *fit,
-			      const char *comment, int require_keys);
+			      const char *comment, int require_keys,
+			      const char *engine_id);
  
 int fit_image_verify(const void *fit, int noffset);
 int fit_config_verify(const void *fit, int conf_noffset);
@@ -1057,6 +1059,7 @@
 	const void *fdt_blob;		/* FDT containing public keys */
 	int required_keynode;		/* Node offset of key to use: -1=any */
 	const char *require_keys;	/* Value for 'required' property */
+	const char *engine_id;		/* Engine to use for signing */
 };
 #endif /* Allow struct image_region to always be defined for rsa.h */
  
@@ -14,6 +14,7 @@
 #include <openssl/err.h>
 #include <openssl/ssl.h>
 #include <openssl/evp.h>
+#include <openssl/engine.h>
  
 #if OPENSSL_VERSION_NUMBER >= 0x10000000L
 #define HAVE_ERR_REMOVE_THREAD_STATE
  
@@ -31,14 +32,14 @@
 }
  
 /**
- * rsa_get_pub_key() - read a public key from a .crt file
+ * rsa_pem_get_pub_key() - read a public key from a .crt file
  *
  * @keydir:	Directory containins the key
  * @name	Name of key file (will have a .crt extension)
  * @rsap	Returns RSA object, or NULL on failure
  * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
  */
-static int rsa_get_pub_key(const char *keydir, const char *name, RSA **rsap)
+static int rsa_pem_get_pub_key(const char *keydir, const char *name, RSA **rsap)
 {
 	char path[1024];
 	EVP_PKEY *key;
  
  
@@ -96,14 +97,90 @@
 }
  
 /**
- * rsa_get_priv_key() - read a private key from a .key file
+ * rsa_engine_get_pub_key() - read a public key from given engine
  *
- * @keydir:	Directory containins the key
+ * @keydir:	Key prefix
+ * @name	Name of key
+ * @engine	Engine to use
+ * @rsap	Returns RSA object, or NULL on failure
+ * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
+ */
+static int rsa_engine_get_pub_key(const char *keydir, const char *name,
+				  ENGINE *engine, RSA **rsap)
+{
+	const char *engine_id;
+	char key_id[1024];
+	EVP_PKEY *key;
+	RSA *rsa;
+	int ret;
+
+	*rsap = NULL;
+
+	engine_id = ENGINE_get_id(engine);
+
+	if (engine_id && !strcmp(engine_id, "pkcs11")) {
+		if (keydir)
+			snprintf(key_id, sizeof(key_id),
+				 "pkcs11:%s;object=%s;type=public",
+				 keydir, name);
+		else
+			snprintf(key_id, sizeof(key_id),
+				 "pkcs11:object=%s;type=public",
+				 name);
+	} else {
+		fprintf(stderr, "Engine not supported\n");
+		return -ENOTSUP;
+	}
+
+	key = ENGINE_load_public_key(engine, key_id, NULL, NULL);
+	if (!key)
+		return rsa_err("Failure loading public key from engine");
+
+	/* Convert to a RSA_style key. */
+	rsa = EVP_PKEY_get1_RSA(key);
+	if (!rsa) {
+		rsa_err("Couldn't convert to a RSA style key");
+		ret = -EINVAL;
+		goto err_rsa;
+	}
+
+	EVP_PKEY_free(key);
+	*rsap = rsa;
+
+	return 0;
+
+err_rsa:
+	EVP_PKEY_free(key);
+	return ret;
+}
+
+/**
+ * rsa_get_pub_key() - read a public key
+ *
+ * @keydir:	Directory containing the key (PEM file) or key prefix (engine)
+ * @name	Name of key file (will have a .crt extension)
+ * @engine	Engine to use
+ * @rsap	Returns RSA object, or NULL on failure
+ * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
+ */
+static int rsa_get_pub_key(const char *keydir, const char *name,
+			   ENGINE *engine, RSA **rsap)
+{
+	if (engine)
+		return rsa_engine_get_pub_key(keydir, name, engine, rsap);
+	return rsa_pem_get_pub_key(keydir, name, rsap);
+}
+
+/**
+ * rsa_pem_get_priv_key() - read a private key from a .key file
+ *
+ * @keydir:	Directory containing the key
  * @name	Name of key file (will have a .key extension)
  * @rsap	Returns RSA object, or NULL on failure
  * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
  */
-static int rsa_get_priv_key(const char *keydir, const char *name, RSA **rsap)
+static int rsa_pem_get_priv_key(const char *keydir, const char *name,
+				RSA **rsap)
 {
 	char path[1024];
 	RSA *rsa;
@@ -130,6 +207,81 @@
 	return 0;
 }
  
+/**
+ * rsa_engine_get_priv_key() - read a private key from given engine
+ *
+ * @keydir:	Key prefix
+ * @name	Name of key
+ * @engine	Engine to use
+ * @rsap	Returns RSA object, or NULL on failure
+ * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
+ */
+static int rsa_engine_get_priv_key(const char *keydir, const char *name,
+				   ENGINE *engine, RSA **rsap)
+{
+	const char *engine_id;
+	char key_id[1024];
+	EVP_PKEY *key;
+	RSA *rsa;
+	int ret;
+
+	*rsap = NULL;
+
+	engine_id = ENGINE_get_id(engine);
+
+	if (engine_id && !strcmp(engine_id, "pkcs11")) {
+		if (keydir)
+			snprintf(key_id, sizeof(key_id),
+				 "pkcs11:%s;object=%s;type=private",
+				 keydir, name);
+		else
+			snprintf(key_id, sizeof(key_id),
+				 "pkcs11:object=%s;type=private",
+				 name);
+	} else {
+		fprintf(stderr, "Engine not supported\n");
+		return -ENOTSUP;
+	}
+
+	key = ENGINE_load_private_key(engine, key_id, NULL, NULL);
+	if (!key)
+		return rsa_err("Failure loading private key from engine");
+
+	/* Convert to a RSA_style key. */
+	rsa = EVP_PKEY_get1_RSA(key);
+	if (!rsa) {
+		rsa_err("Couldn't convert to a RSA style key");
+		ret = -EINVAL;
+		goto err_rsa;
+	}
+
+	EVP_PKEY_free(key);
+	*rsap = rsa;
+
+	return 0;
+
+err_rsa:
+	EVP_PKEY_free(key);
+	return ret;
+}
+
+/**
+ * rsa_get_priv_key() - read a private key
+ *
+ * @keydir:	Directory containing the key (PEM file) or key prefix (engine)
+ * @name	Name of key
+ * @engine	Engine to use for signing
+ * @rsap	Returns RSA object, or NULL on failure
+ * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
+ */
+static int rsa_get_priv_key(const char *keydir, const char *name,
+			    ENGINE *engine, RSA **rsap)
+{
+	if (engine)
+		return rsa_engine_get_priv_key(keydir, name, engine, rsap);
+	return rsa_pem_get_priv_key(keydir, name, rsap);
+}
+
 static int rsa_init(void)
 {
 	int ret;
@@ -148,6 +300,45 @@
 	return 0;
 }
  
+static int rsa_engine_init(const char *engine_id, ENGINE **pe)
+{
+	ENGINE *e;
+	int ret;
+
+	ENGINE_load_builtin_engines();
+
+	e = ENGINE_by_id(engine_id);
+	if (!e) {
+		fprintf(stderr, "Engine isn't available\n");
+		ret = -1;
+		goto err_engine_by_id;
+	}
+
+	if (!ENGINE_init(e)) {
+		fprintf(stderr, "Couldn't initialize engine\n");
+		ret = -1;
+		goto err_engine_init;
+	}
+
+	if (!ENGINE_set_default_RSA(e)) {
+		fprintf(stderr, "Couldn't set engine as default for RSA\n");
+		ret = -1;
+		goto err_set_rsa;
+	}
+
+	*pe = e;
+
+	return 0;
+
+err_set_rsa:
+	ENGINE_finish(e);
+err_engine_init:
+	ENGINE_free(e);
+err_engine_by_id:
+	ENGINE_cleanup();
+	return ret;
+}
+
 static void rsa_remove(void)
 {
 	CRYPTO_cleanup_all_ex_data();
@@ -160,6 +351,14 @@
 	EVP_cleanup();
 }
  
+static void rsa_engine_remove(ENGINE *e)
+{
+	if (e) {
+		ENGINE_finish(e);
+		ENGINE_free(e);
+	}
+}
+
 static int rsa_sign_with_key(RSA *rsa, struct checksum_algo *checksum_algo,
 		const struct image_region region[], int region_count,
 		uint8_t **sigp, uint *sig_size)
  
@@ -235,13 +434,20 @@
 	     uint8_t **sigp, uint *sig_len)
 {
 	RSA *rsa;
+	ENGINE *e = NULL;
 	int ret;
  
 	ret = rsa_init();
 	if (ret)
 		return ret;
  
-	ret = rsa_get_priv_key(info->keydir, info->keyname, &rsa);
+	if (info->engine_id) {
+		ret = rsa_engine_init(info->engine_id, &e);
+		if (ret)
+			goto err_engine;
+	}
+
+	ret = rsa_get_priv_key(info->keydir, info->keyname, e, &rsa);
 	if (ret)
 		goto err_priv;
 	ret = rsa_sign_with_key(rsa, info->checksum, region,
@@ -250,6 +456,8 @@
 		goto err_sign;
  
 	RSA_free(rsa);
+	if (info->engine_id)
+		rsa_engine_remove(e);
 	rsa_remove();
  
 	return ret;
@@ -257,6 +465,9 @@
 err_sign:
 	RSA_free(rsa);
 err_priv:
+	if (info->engine_id)
+		rsa_engine_remove(e);
+err_engine:
 	rsa_remove();
 	return ret;
 }
  
  
  
@@ -446,14 +657,20 @@
 	int ret;
 	int bits;
 	RSA *rsa;
+	ENGINE *e = NULL;
  
 	debug("%s: Getting verification data\n", __func__);
-	ret = rsa_get_pub_key(info->keydir, info->keyname, &rsa);
+	if (info->engine_id) {
+		ret = rsa_engine_init(info->engine_id, &e);
+		if (ret)
+			return ret;
+	}
+	ret = rsa_get_pub_key(info->keydir, info->keyname, e, &rsa);
 	if (ret)
-		return ret;
+		goto err_get_pub_key;
 	ret = rsa_get_params(rsa, &exponent, &n0_inv, &modulus, &r_squared);
 	if (ret)
-		return ret;
+		goto err_get_params;
 	bits = BN_num_bits(modulus);
 	parent = fdt_subnode_offset(keydest, 0, FIT_SIG_NODENAME);
 	if (parent == -FDT_ERR_NOTFOUND) {
  
@@ -518,8 +735,13 @@
 	BN_free(modulus);
 	BN_free(r_squared);
 	if (ret)
-		return ret == -FDT_ERR_NOSPACE ? -ENOSPC : -EIO;
+		ret = ret == -FDT_ERR_NOSPACE ? -ENOSPC : -EIO;
+err_get_params:
+	RSA_free(rsa);
+err_get_pub_key:
+	if (info->engine_id)
+		rsa_engine_remove(e);
  
-	return 0;
+	return ret;
 }
@@ -59,7 +59,8 @@
 	if (!ret) {
 		ret = fit_add_verification_data(params->keydir, dest_blob, ptr,
 						params->comment,
-						params->require_keys);
+						params->require_keys,
+						params->engine_id);
 	}
  
 	if (dest_blob) {
@@ -149,7 +149,7 @@
  
 static int fit_image_setup_sig(struct image_sign_info *info,
 		const char *keydir, void *fit, const char *image_name,
-		int noffset, const char *require_keys)
+		int noffset, const char *require_keys, const char *engine_id)
 {
 	const char *node_name;
 	char *algo_name;
@@ -170,6 +170,7 @@
 	info->checksum = image_get_checksum_algo(algo_name);
 	info->crypto = image_get_crypto_algo(algo_name);
 	info->require_keys = require_keys;
+	info->engine_id = engine_id;
 	if (!info->checksum || !info->crypto) {
 		printf("Unsupported signature algorithm (%s) for '%s' signature node in '%s' image node\n",
 		       algo_name, node_name, image_name);
  
@@ -194,12 +195,13 @@
  * @size:	size of data in bytes
  * @comment:	Comment to add to signature nodes
  * @require_keys: Mark all keys as 'required'
+ * @engine_id:	Engine to use for signing
  * @return 0 if ok, -1 on error
  */
 static int fit_image_process_sig(const char *keydir, void *keydest,
 		void *fit, const char *image_name,
 		int noffset, const void *data, size_t size,
-		const char *comment, int require_keys)
+		const char *comment, int require_keys, const char *engine_id)
 {
 	struct image_sign_info info;
 	struct image_region region;
@@ -209,7 +211,7 @@
 	int ret;
  
 	if (fit_image_setup_sig(&info, keydir, fit, image_name, noffset,
-				require_keys ? "image" : NULL))
+				require_keys ? "image" : NULL, engine_id))
 		return -1;
  
 	node_name = fit_get_name(fit, noffset, NULL);
  
@@ -288,11 +290,12 @@
  * @image_noffset: Requested component image node
  * @comment:	Comment to add to signature nodes
  * @require_keys: Mark all keys as 'required'
+ * @engine_id:	Engine to use for signing
  * @return: 0 on success, <0 on failure
  */
 int fit_image_add_verification_data(const char *keydir, void *keydest,
 		void *fit, int image_noffset, const char *comment,
-		int require_keys)
+		int require_keys, const char *engine_id)
 {
 	const char *image_name;
 	const void *data;
@@ -329,7 +332,7 @@
 				strlen(FIT_SIG_NODENAME))) {
 			ret = fit_image_process_sig(keydir, keydest,
 				fit, image_name, noffset, data, size,
-				comment, require_keys);
+				comment, require_keys, engine_id);
 		}
 		if (ret)
 			return ret;
@@ -569,7 +572,8 @@
  
 static int fit_config_process_sig(const char *keydir, void *keydest,
 		void *fit, const char *conf_name, int conf_noffset,
-		int noffset, const char *comment, int require_keys)
+		int noffset, const char *comment, int require_keys,
+		const char *engine_id)
 {
 	struct image_sign_info info;
 	const char *node_name;
@@ -587,7 +591,7 @@
 		return -1;
  
 	if (fit_image_setup_sig(&info, keydir, fit, conf_name, noffset,
-				require_keys ? "conf" : NULL))
+				require_keys ? "conf" : NULL, engine_id))
 		return -1;
  
 	ret = info.crypto->sign(&info, region, region_count, &value,
@@ -635,7 +639,7 @@
  
 static int fit_config_add_verification_data(const char *keydir, void *keydest,
 		void *fit, int conf_noffset, const char *comment,
-		int require_keys)
+		int require_keys, const char *engine_id)
 {
 	const char *conf_name;
 	int noffset;
@@ -654,7 +658,7 @@
 			     strlen(FIT_SIG_NODENAME))) {
 			ret = fit_config_process_sig(keydir, keydest,
 				fit, conf_name, conf_noffset, noffset, comment,
-				require_keys);
+				require_keys, engine_id);
 		}
 		if (ret)
 			return ret;
@@ -664,7 +668,8 @@
 }
  
 int fit_add_verification_data(const char *keydir, void *keydest, void *fit,
-			      const char *comment, int require_keys)
+			      const char *comment, int require_keys,
+			      const char *engine_id)
 {
 	int images_noffset, confs_noffset;
 	int noffset;
@@ -687,7 +692,7 @@
 		 * i.e. component image node.
 		 */
 		ret = fit_image_add_verification_data(keydir, keydest,
-				fit, noffset, comment, require_keys);
+				fit, noffset, comment, require_keys, engine_id);
 		if (ret)
 			return ret;
 	}
@@ -710,7 +715,8 @@
 	     noffset = fdt_next_subnode(fit, noffset)) {
 		ret = fit_config_add_verification_data(keydir, keydest,
 						       fit, noffset, comment,
-						       require_keys);
+						       require_keys,
+						       engine_id);
 		if (ret)
 			return ret;
 	}
@@ -76,6 +76,7 @@
 	bool external_data;	/* Store data outside the FIT */
 	bool quiet;		/* Don't output text in normal operation */
 	unsigned int external_offset;	/* Add padding to external data */
+	const char *engine_id;	/* Engine to use for signing */
 };
  
 /*
@@ -98,14 +98,15 @@
 		"          -i => input filename for ramdisk file\n");
 #ifdef CONFIG_FIT_SIGNATURE
 	fprintf(stderr,
-		"Signing / verified boot options: [-E] [-k keydir] [-K dtb] [ -c <comment>] [-p addr] [-r]\n"
+		"Signing / verified boot options: [-E] [-k keydir] [-K dtb] [ -c <comment>] [-p addr] [-r] [-N engine]\n"
 		"          -E => place data outside of the FIT structure\n"
 		"          -k => set directory containing private keys\n"
 		"          -K => write public keys to this .dtb file\n"
 		"          -c => add comment in signature node\n"
 		"          -F => re-sign existing FIT image\n"
 		"          -p => place external data at a static position\n"
-		"          -r => mark keys used as 'required' in dtb\n");
+		"          -r => mark keys used as 'required' in dtb\n"
+		"          -N => engine to use for signing (pkcs11)\n");
 #else
 	fprintf(stderr,
 		"Signing / verified boot not supported (CONFIG_FIT_SIGNATURE undefined)\n");
@@ -143,7 +144,7 @@
 	int opt;
  
 	while ((opt = getopt(argc, argv,
-			     "a:A:b:c:C:d:D:e:Ef:Fk:i:K:ln:p:O:rR:qsT:vVx")) != -1) {
+			     "a:A:b:c:C:d:D:e:Ef:Fk:i:K:ln:N:p:O:rR:qsT:vVx")) != -1) {
 		switch (opt) {
 		case 'a':
 			params.addr = strtoull(optarg, &ptr, 16);
@@ -223,6 +224,9 @@
 			break;
 		case 'n':
 			params.imagename = optarg;
+			break;
+		case 'N':
+			params.engine_id = optarg;
 			break;
 		case 'O':
 			params.os = genimg_get_os_id(optarg);
...	...	@@ -385,6 +385,149 @@
385	385	Test passed
386	386
387	387
	388	+Hardware Signing with PKCS#11
	389	+-----------------------------
	390	+
	391	+Securely managing private signing keys can challenging, especially when the
	392	+keys are stored on the file system of a computer that is connected to the
	393	+Internet. If an attacker is able to steal the key, they can sign malicious FIT
	394	+images which will appear genuine to your devices.
	395	+
	396	+An alternative solution is to keep your signing key securely stored on hardware
	397	+device like a smartcard, USB token or Hardware Security Module (HSM) and have
	398	+them perform the signing. PKCS#11 is standard for interfacing with these crypto
	399	+device.
	400	+
	401	+Requirements:
	402	+Smartcard/USB token/HSM which can work with the pkcs11 engine
	403	+openssl
	404	+libp11 (provides pkcs11 engine)
	405	+p11-kit (recommended to simplify setup)
	406	+opensc (for smartcards and smartcard like USB devices)
	407	+gnutls (recommended for key generation, p11tool)
	408	+
	409	+The following examples use the Nitrokey Pro. Instructions for other devices may vary.
	410	+
	411	+Notes on pkcs11 engine setup:
	412	+
	413	+Make sure p11-kit, opensc are installed and that p11-kit is setup to use opensc.
	414	+/usr/share/p11-kit/modules/opensc.module should be present on your system.
	415	+
	416	+
	417	+Generating Keys On the Nitrokey:
	418	+
	419	+$ gpg --card-edit
	420	+
	421	+Reader ...........: Nitrokey Nitrokey Pro (xxxxxxxx0000000000000000) 00 00
	422	+Application ID ...: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
	423	+Version ..........: 2.1
	424	+Manufacturer .....: ZeitControl
	425	+Serial number ....: xxxxxxxx
	426	+Name of cardholder: [not set]
	427	+Language prefs ...: de
	428	+Sex ..............: unspecified
	429	+URL of public key : [not set]
	430	+Login data .......: [not set]
	431	+Signature PIN ....: forced
	432	+Key attributes ...: rsa2048 rsa2048 rsa2048
	433	+Max. PIN lengths .: 32 32 32
	434	+PIN retry counter : 3 0 3
	435	+Signature counter : 0
	436	+Signature key ....: [none]
	437	+Encryption key....: [none]
	438	+Authentication key: [none]
	439	+General key info..: [none]
	440	+
	441	+gpg/card> generate
	442	+Make off-card backup of encryption key? (Y/n) n
	443	+
	444	+Please note that the factory settings of the PINs are
	445	+ PIN = '123456' Admin PIN = '12345678'
	446	+You should change them using the command --change-pin
	447	+
	448	+What keysize do you want for the Signature key? (2048) 4096
	449	+The card will now be re-configured to generate a key of 4096 bits
	450	+Note: There is no guarantee that the card supports the requested size.
	451	+ If the key generation does not succeed, please check the
	452	+ documentation of your card to see what sizes are allowed.
	453	+What keysize do you want for the Encryption key? (2048) 4096
	454	+The card will now be re-configured to generate a key of 4096 bits
	455	+What keysize do you want for the Authentication key? (2048) 4096
	456	+The card will now be re-configured to generate a key of 4096 bits
	457	+Please specify how long the key should be valid.
	458	+ 0 = key does not expire
	459	+ <n> = key expires in n days
	460	+ <n>w = key expires in n weeks
	461	+ <n>m = key expires in n months
	462	+ <n>y = key expires in n years
	463	+Key is valid for? (0)
	464	+Key does not expire at all
	465	+Is this correct? (y/N) y
	466	+
	467	+GnuPG needs to construct a user ID to identify your key.
	468	+
	469	+Real name: John Doe
	470	+Email address: john.doe@email.com
	471	+Comment:
	472	+You selected this USER-ID:
	473	+ "John Doe <john.doe@email.com>"
	474	+
	475	+Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o
	476	+
	477	+
	478	+Using p11tool to get the token URL:
	479	+
	480	+Depending on system configuration, gpg-agent may need to be killed first.
	481	+
	482	+$ p11tool --provider /usr/lib/opensc-pkcs11.so --list-tokens
	483	+Token 0:
	484	+URL: pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29
	485	+Label: OpenPGP card (User PIN (sig))
	486	+Type: Hardware token
	487	+Manufacturer: ZeitControl
	488	+Model: PKCS#15 emulated
	489	+Serial: 000xxxxxxxxx
	490	+Module: (null)
	491	+
	492	+
	493	+Token 1:
	494	+URL: pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%29
	495	+Label: OpenPGP card (User PIN)
	496	+Type: Hardware token
	497	+Manufacturer: ZeitControl
	498	+Model: PKCS#15 emulated
	499	+Serial: 000xxxxxxxxx
	500	+Module: (null)
	501	+
	502	+Use the portion of the signature token URL after "pkcs11:" as the keydir argument (-k) to mkimage below.
	503	+
	504	+
	505	+Use the URL of the token to list the private keys:
	506	+
	507	+$ p11tool --login --provider /usr/lib/opensc-pkcs11.so --list-privkeys \
	508	+"pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29"
	509	+Token 'OpenPGP card (User PIN (sig))' with URL 'pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29' requires user PIN
	510	+Enter PIN:
	511	+Object 0:
	512	+URL: pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29;id=%01;object=Signature%20key;type=private
	513	+Type: Private key
	514	+Label: Signature key
	515	+Flags: CKA_PRIVATE; CKA_NEVER_EXTRACTABLE; CKA_SENSITIVE;
	516	+ID: 01
	517	+
	518	+Use the label, in this case "Signature key" as the key-name-hint in your FIT.
	519	+
	520	+Create the fitImage:
	521	+$ ./tools/mkimage -f fit-image.its fitImage
	522	+
	523	+
	524	+Sign the fitImage with the hardware key:
	525	+
	526	+$ ./tools/mkimage -F -k \
	527	+"model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29" \
	528	+-K u-boot.dtb -N pkcs11 -r fitImage
	529	+
	530	+
388	531	Future Work
389	532	-----------
390	533	- Roll-back protection using a TPM is done using the tpm command. This can
...	...	@@ -965,6 +965,7 @@
965	965	* @fit: Pointer to the FIT format image header
966	966	* @comment: Comment to add to signature nodes
967	967	* @require_keys: Mark all keys as 'required'
	968	+ * @engine_id: Engine to use for signing
968	969	*
969	970	* Adds hash values for all component images in the FIT blob.
970	971	* Hashes are calculated for all component images which have hash subnodes
...	...	@@ -977,7 +978,8 @@
977	978	* libfdt error code, on failure
978	979	*/
979	980	int fit_add_verification_data(const char keydir, void keydest, void *fit,
980		- const char *comment, int require_keys);
	981	+ const char *comment, int require_keys,
	982	+ const char *engine_id);
981	983
982	984	int fit_image_verify(const void *fit, int noffset);
983	985	int fit_config_verify(const void *fit, int conf_noffset);
...	...	@@ -1057,6 +1059,7 @@
1057	1059	const void fdt_blob; / FDT containing public keys */
1058	1060	int required_keynode; /* Node offset of key to use: -1=any */
1059	1061	const char require_keys; / Value for 'required' property */
	1062	+ const char engine_id; / Engine to use for signing */
1060	1063	};
1061	1064	#endif /* Allow struct image_region to always be defined for rsa.h */
1062	1065
...	...	@@ -14,6 +14,7 @@
14	14	#include <openssl/err.h>
15	15	#include <openssl/ssl.h>
16	16	#include <openssl/evp.h>
	17	+#include <openssl/engine.h>
17	18
18	19	#if OPENSSL_VERSION_NUMBER >= 0x10000000L
19	20	#define HAVE_ERR_REMOVE_THREAD_STATE
20	21
...	...	@@ -31,14 +32,14 @@
31	32	}
32	33
33	34	/**
34		- * rsa_get_pub_key() - read a public key from a .crt file
	35	+ * rsa_pem_get_pub_key() - read a public key from a .crt file
35	36	*
36	37	* @keydir: Directory containins the key
37	38	* @name Name of key file (will have a .crt extension)
38	39	* @rsap Returns RSA object, or NULL on failure
39	40	* @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
40	41	*/
41		-static int rsa_get_pub_key(const char keydir, const char name, RSA **rsap)
	42	+static int rsa_pem_get_pub_key(const char keydir, const char name, RSA **rsap)
42	43	{
43	44	char path[1024];
44	45	EVP_PKEY *key;
45	46
46	47
...	...	@@ -96,14 +97,90 @@
96	97	}
97	98
98	99	/**
99		- * rsa_get_priv_key() - read a private key from a .key file
	100	+ * rsa_engine_get_pub_key() - read a public key from given engine
100	101	*
101		- * @keydir: Directory containins the key
	102	+ * @keydir: Key prefix
	103	+ * @name Name of key
	104	+ * @engine Engine to use
	105	+ * @rsap Returns RSA object, or NULL on failure
	106	+ * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
	107	+ */
	108	+static int rsa_engine_get_pub_key(const char keydir, const char name,
	109	+ ENGINE engine, RSA *rsap)
	110	+{
	111	+ const char *engine_id;
	112	+ char key_id[1024];
	113	+ EVP_PKEY *key;
	114	+ RSA *rsa;
	115	+ int ret;
	116	+
	117	+ *rsap = NULL;
	118	+
	119	+ engine_id = ENGINE_get_id(engine);
	120	+
	121	+ if (engine_id && !strcmp(engine_id, "pkcs11")) {
	122	+ if (keydir)
	123	+ snprintf(key_id, sizeof(key_id),
	124	+ "pkcs11:%s;object=%s;type=public",
	125	+ keydir, name);
	126	+ else
	127	+ snprintf(key_id, sizeof(key_id),
	128	+ "pkcs11:object=%s;type=public",
	129	+ name);
	130	+ } else {
	131	+ fprintf(stderr, "Engine not supported\n");
	132	+ return -ENOTSUP;
	133	+ }
	134	+
	135	+ key = ENGINE_load_public_key(engine, key_id, NULL, NULL);
	136	+ if (!key)
	137	+ return rsa_err("Failure loading public key from engine");
	138	+
	139	+ /* Convert to a RSA_style key. */
	140	+ rsa = EVP_PKEY_get1_RSA(key);
	141	+ if (!rsa) {
	142	+ rsa_err("Couldn't convert to a RSA style key");
	143	+ ret = -EINVAL;
	144	+ goto err_rsa;
	145	+ }
	146	+
	147	+ EVP_PKEY_free(key);
	148	+ *rsap = rsa;
	149	+
	150	+ return 0;
	151	+
	152	+err_rsa:
	153	+ EVP_PKEY_free(key);
	154	+ return ret;
	155	+}
	156	+
	157	+/**
	158	+ * rsa_get_pub_key() - read a public key
	159	+ *
	160	+ * @keydir: Directory containing the key (PEM file) or key prefix (engine)
	161	+ * @name Name of key file (will have a .crt extension)
	162	+ * @engine Engine to use
	163	+ * @rsap Returns RSA object, or NULL on failure
	164	+ * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
	165	+ */
	166	+static int rsa_get_pub_key(const char keydir, const char name,
	167	+ ENGINE engine, RSA *rsap)
	168	+{
	169	+ if (engine)
	170	+ return rsa_engine_get_pub_key(keydir, name, engine, rsap);
	171	+ return rsa_pem_get_pub_key(keydir, name, rsap);
	172	+}
	173	+
	174	+/**
	175	+ * rsa_pem_get_priv_key() - read a private key from a .key file
	176	+ *
	177	+ * @keydir: Directory containing the key
102	178	* @name Name of key file (will have a .key extension)
103	179	* @rsap Returns RSA object, or NULL on failure
104	180	* @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
105	181	*/
106		-static int rsa_get_priv_key(const char keydir, const char name, RSA **rsap)
	182	+static int rsa_pem_get_priv_key(const char keydir, const char name,
	183	+ RSA **rsap)
107	184	{
108	185	char path[1024];
109	186	RSA *rsa;
...	...	@@ -130,6 +207,81 @@
130	207	return 0;
131	208	}
132	209
	210	+/**
	211	+ * rsa_engine_get_priv_key() - read a private key from given engine
	212	+ *
	213	+ * @keydir: Key prefix
	214	+ * @name Name of key
	215	+ * @engine Engine to use
	216	+ * @rsap Returns RSA object, or NULL on failure
	217	+ * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
	218	+ */
	219	+static int rsa_engine_get_priv_key(const char keydir, const char name,
	220	+ ENGINE engine, RSA *rsap)
	221	+{
	222	+ const char *engine_id;
	223	+ char key_id[1024];
	224	+ EVP_PKEY *key;
	225	+ RSA *rsa;
	226	+ int ret;
	227	+
	228	+ *rsap = NULL;
	229	+
	230	+ engine_id = ENGINE_get_id(engine);
	231	+
	232	+ if (engine_id && !strcmp(engine_id, "pkcs11")) {
	233	+ if (keydir)
	234	+ snprintf(key_id, sizeof(key_id),
	235	+ "pkcs11:%s;object=%s;type=private",
	236	+ keydir, name);
	237	+ else
	238	+ snprintf(key_id, sizeof(key_id),
	239	+ "pkcs11:object=%s;type=private",
	240	+ name);
	241	+ } else {
	242	+ fprintf(stderr, "Engine not supported\n");
	243	+ return -ENOTSUP;
	244	+ }
	245	+
	246	+ key = ENGINE_load_private_key(engine, key_id, NULL, NULL);
	247	+ if (!key)
	248	+ return rsa_err("Failure loading private key from engine");
	249	+
	250	+ /* Convert to a RSA_style key. */
	251	+ rsa = EVP_PKEY_get1_RSA(key);
	252	+ if (!rsa) {
	253	+ rsa_err("Couldn't convert to a RSA style key");
	254	+ ret = -EINVAL;
	255	+ goto err_rsa;
	256	+ }
	257	+
	258	+ EVP_PKEY_free(key);
	259	+ *rsap = rsa;
	260	+
	261	+ return 0;
	262	+
	263	+err_rsa:
	264	+ EVP_PKEY_free(key);
	265	+ return ret;
	266	+}
	267	+
	268	+/**
	269	+ * rsa_get_priv_key() - read a private key
	270	+ *
	271	+ * @keydir: Directory containing the key (PEM file) or key prefix (engine)
	272	+ * @name Name of key
	273	+ * @engine Engine to use for signing
	274	+ * @rsap Returns RSA object, or NULL on failure
	275	+ * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
	276	+ */
	277	+static int rsa_get_priv_key(const char keydir, const char name,
	278	+ ENGINE engine, RSA *rsap)
	279	+{
	280	+ if (engine)
	281	+ return rsa_engine_get_priv_key(keydir, name, engine, rsap);
	282	+ return rsa_pem_get_priv_key(keydir, name, rsap);
	283	+}
	284	+
133	285	static int rsa_init(void)
134	286	{
135	287	int ret;
...	...	@@ -148,6 +300,45 @@
148	300	return 0;
149	301	}
150	302
	303	+static int rsa_engine_init(const char engine_id, ENGINE *pe)
	304	+{
	305	+ ENGINE *e;
	306	+ int ret;
	307	+
	308	+ ENGINE_load_builtin_engines();
	309	+
	310	+ e = ENGINE_by_id(engine_id);
	311	+ if (!e) {
	312	+ fprintf(stderr, "Engine isn't available\n");
	313	+ ret = -1;
	314	+ goto err_engine_by_id;
	315	+ }
	316	+
	317	+ if (!ENGINE_init(e)) {
	318	+ fprintf(stderr, "Couldn't initialize engine\n");
	319	+ ret = -1;
	320	+ goto err_engine_init;
	321	+ }
	322	+
	323	+ if (!ENGINE_set_default_RSA(e)) {
	324	+ fprintf(stderr, "Couldn't set engine as default for RSA\n");
	325	+ ret = -1;
	326	+ goto err_set_rsa;
	327	+ }
	328	+
	329	+ *pe = e;
	330	+
	331	+ return 0;
	332	+
	333	+err_set_rsa:
	334	+ ENGINE_finish(e);
	335	+err_engine_init:
	336	+ ENGINE_free(e);
	337	+err_engine_by_id:
	338	+ ENGINE_cleanup();
	339	+ return ret;
	340	+}
	341	+
151	342	static void rsa_remove(void)
152	343	{
153	344	CRYPTO_cleanup_all_ex_data();
...	...	@@ -160,6 +351,14 @@
160	351	EVP_cleanup();
161	352	}
162	353
	354	+static void rsa_engine_remove(ENGINE *e)
	355	+{
	356	+ if (e) {
	357	+ ENGINE_finish(e);
	358	+ ENGINE_free(e);
	359	+ }
	360	+}
	361	+
163	362	static int rsa_sign_with_key(RSA rsa, struct checksum_algo checksum_algo,
164	363	const struct image_region region[], int region_count,
165	364	uint8_t *sigp, uint sig_size)
166	365
...	...	@@ -235,13 +434,20 @@
235	434	uint8_t *sigp, uint sig_len)
236	435	{
237	436	RSA *rsa;
	437	+ ENGINE *e = NULL;
238	438	int ret;
239	439
240	440	ret = rsa_init();
241	441	if (ret)
242	442	return ret;
243	443
244		- ret = rsa_get_priv_key(info->keydir, info->keyname, &rsa);
	444	+ if (info->engine_id) {
	445	+ ret = rsa_engine_init(info->engine_id, &e);
	446	+ if (ret)
	447	+ goto err_engine;
	448	+ }
	449	+
	450	+ ret = rsa_get_priv_key(info->keydir, info->keyname, e, &rsa);
245	451	if (ret)
246	452	goto err_priv;
247	453	ret = rsa_sign_with_key(rsa, info->checksum, region,
...	...	@@ -250,6 +456,8 @@
250	456	goto err_sign;
251	457
252	458	RSA_free(rsa);
	459	+ if (info->engine_id)
	460	+ rsa_engine_remove(e);
253	461	rsa_remove();
254	462
255	463	return ret;
...	...	@@ -257,6 +465,9 @@
257	465	err_sign:
258	466	RSA_free(rsa);
259	467	err_priv:
	468	+ if (info->engine_id)
	469	+ rsa_engine_remove(e);
	470	+err_engine:
260	471	rsa_remove();
261	472	return ret;
262	473	}
263	474
264	475
265	476
...	...	@@ -446,14 +657,20 @@
446	657	int ret;
447	658	int bits;
448	659	RSA *rsa;
	660	+ ENGINE *e = NULL;
449	661
450	662	debug("%s: Getting verification data\n", __func__);
451		- ret = rsa_get_pub_key(info->keydir, info->keyname, &rsa);
	663	+ if (info->engine_id) {
	664	+ ret = rsa_engine_init(info->engine_id, &e);
	665	+ if (ret)
	666	+ return ret;
	667	+ }
	668	+ ret = rsa_get_pub_key(info->keydir, info->keyname, e, &rsa);
452	669	if (ret)
453		- return ret;
	670	+ goto err_get_pub_key;
454	671	ret = rsa_get_params(rsa, &exponent, &n0_inv, &modulus, &r_squared);
455	672	if (ret)
456		- return ret;
	673	+ goto err_get_params;
457	674	bits = BN_num_bits(modulus);
458	675	parent = fdt_subnode_offset(keydest, 0, FIT_SIG_NODENAME);
459	676	if (parent == -FDT_ERR_NOTFOUND) {
460	677
...	...	@@ -518,8 +735,13 @@
518	735	BN_free(modulus);
519	736	BN_free(r_squared);
520	737	if (ret)
521		- return ret == -FDT_ERR_NOSPACE ? -ENOSPC : -EIO;
	738	+ ret = ret == -FDT_ERR_NOSPACE ? -ENOSPC : -EIO;
	739	+err_get_params:
	740	+ RSA_free(rsa);
	741	+err_get_pub_key:
	742	+ if (info->engine_id)
	743	+ rsa_engine_remove(e);
522	744
523		- return 0;
	745	+ return ret;
524	746	}
...	...	@@ -59,7 +59,8 @@
59	59	if (!ret) {
60	60	ret = fit_add_verification_data(params->keydir, dest_blob, ptr,
61	61	params->comment,
62		- params->require_keys);
	62	+ params->require_keys,
	63	+ params->engine_id);
63	64	}
64	65
65	66	if (dest_blob) {
...	...	@@ -149,7 +149,7 @@
149	149
150	150	static int fit_image_setup_sig(struct image_sign_info *info,
151	151	const char keydir, void fit, const char *image_name,
152		- int noffset, const char *require_keys)
	152	+ int noffset, const char require_keys, const char engine_id)
153	153	{
154	154	const char *node_name;
155	155	char *algo_name;
...	...	@@ -170,6 +170,7 @@
170	170	info->checksum = image_get_checksum_algo(algo_name);
171	171	info->crypto = image_get_crypto_algo(algo_name);
172	172	info->require_keys = require_keys;
	173	+ info->engine_id = engine_id;
173	174	if (!info->checksum \|\| !info->crypto) {
174	175	printf("Unsupported signature algorithm (%s) for '%s' signature node in '%s' image node\n",
175	176	algo_name, node_name, image_name);
176	177
...	...	@@ -194,12 +195,13 @@
194	195	* @size: size of data in bytes
195	196	* @comment: Comment to add to signature nodes
196	197	* @require_keys: Mark all keys as 'required'
	198	+ * @engine_id: Engine to use for signing
197	199	* @return 0 if ok, -1 on error
198	200	*/
199	201	static int fit_image_process_sig(const char keydir, void keydest,
200	202	void fit, const char image_name,
201	203	int noffset, const void *data, size_t size,
202		- const char *comment, int require_keys)
	204	+ const char comment, int require_keys, const char engine_id)
203	205	{
204	206	struct image_sign_info info;
205	207	struct image_region region;
...	...	@@ -209,7 +211,7 @@
209	211	int ret;
210	212
211	213	if (fit_image_setup_sig(&info, keydir, fit, image_name, noffset,
212		- require_keys ? "image" : NULL))
	214	+ require_keys ? "image" : NULL, engine_id))
213	215	return -1;
214	216
215	217	node_name = fit_get_name(fit, noffset, NULL);
216	218
...	...	@@ -288,11 +290,12 @@
288	290	* @image_noffset: Requested component image node
289	291	* @comment: Comment to add to signature nodes
290	292	* @require_keys: Mark all keys as 'required'
	293	+ * @engine_id: Engine to use for signing
291	294	* @return: 0 on success, <0 on failure
292	295	*/
293	296	int fit_image_add_verification_data(const char keydir, void keydest,
294	297	void fit, int image_noffset, const char comment,
295		- int require_keys)
	298	+ int require_keys, const char *engine_id)
296	299	{
297	300	const char *image_name;
298	301	const void *data;
...	...	@@ -329,7 +332,7 @@
329	332	strlen(FIT_SIG_NODENAME))) {
330	333	ret = fit_image_process_sig(keydir, keydest,
331	334	fit, image_name, noffset, data, size,
332		- comment, require_keys);
	335	+ comment, require_keys, engine_id);
333	336	}
334	337	if (ret)
335	338	return ret;
...	...	@@ -569,7 +572,8 @@
569	572
570	573	static int fit_config_process_sig(const char keydir, void keydest,
571	574	void fit, const char conf_name, int conf_noffset,
572		- int noffset, const char *comment, int require_keys)
	575	+ int noffset, const char *comment, int require_keys,
	576	+ const char *engine_id)
573	577	{
574	578	struct image_sign_info info;
575	579	const char *node_name;
...	...	@@ -587,7 +591,7 @@
587	591	return -1;
588	592
589	593	if (fit_image_setup_sig(&info, keydir, fit, conf_name, noffset,
590		- require_keys ? "conf" : NULL))
	594	+ require_keys ? "conf" : NULL, engine_id))
591	595	return -1;
592	596
593	597	ret = info.crypto->sign(&info, region, region_count, &value,
...	...	@@ -635,7 +639,7 @@
635	639
636	640	static int fit_config_add_verification_data(const char keydir, void keydest,
637	641	void fit, int conf_noffset, const char comment,
638		- int require_keys)
	642	+ int require_keys, const char *engine_id)
639	643	{
640	644	const char *conf_name;
641	645	int noffset;
...	...	@@ -654,7 +658,7 @@
654	658	strlen(FIT_SIG_NODENAME))) {
655	659	ret = fit_config_process_sig(keydir, keydest,
656	660	fit, conf_name, conf_noffset, noffset, comment,
657		- require_keys);
	661	+ require_keys, engine_id);
658	662	}
659	663	if (ret)
660	664	return ret;
...	...	@@ -664,7 +668,8 @@
664	668	}
665	669
666	670	int fit_add_verification_data(const char keydir, void keydest, void *fit,
667		- const char *comment, int require_keys)
	671	+ const char *comment, int require_keys,
	672	+ const char *engine_id)
668	673	{
669	674	int images_noffset, confs_noffset;
670	675	int noffset;
...	...	@@ -687,7 +692,7 @@
687	692	* i.e. component image node.
688	693	*/
689	694	ret = fit_image_add_verification_data(keydir, keydest,
690		- fit, noffset, comment, require_keys);
	695	+ fit, noffset, comment, require_keys, engine_id);
691	696	if (ret)
692	697	return ret;
693	698	}
...	...	@@ -710,7 +715,8 @@
710	715	noffset = fdt_next_subnode(fit, noffset)) {
711	716	ret = fit_config_add_verification_data(keydir, keydest,
712	717	fit, noffset, comment,
713		- require_keys);
	718	+ require_keys,
	719	+ engine_id);
714	720	if (ret)
715	721	return ret;
716	722	}
...	...	@@ -76,6 +76,7 @@
76	76	bool external_data; /* Store data outside the FIT */
77	77	bool quiet; /* Don't output text in normal operation */
78	78	unsigned int external_offset; /* Add padding to external data */
	79	+ const char engine_id; / Engine to use for signing */
79	80	};
80	81
81	82	/*
...	...	@@ -98,14 +98,15 @@
98	98	" -i => input filename for ramdisk file\n");
99	99	#ifdef CONFIG_FIT_SIGNATURE
100	100	fprintf(stderr,
101		- "Signing / verified boot options: [-E] [-k keydir] [-K dtb] [ -c <comment>] [-p addr] [-r]\n"
	101	+ "Signing / verified boot options: [-E] [-k keydir] [-K dtb] [ -c <comment>] [-p addr] [-r] [-N engine]\n"
102	102	" -E => place data outside of the FIT structure\n"
103	103	" -k => set directory containing private keys\n"
104	104	" -K => write public keys to this .dtb file\n"
105	105	" -c => add comment in signature node\n"
106	106	" -F => re-sign existing FIT image\n"
107	107	" -p => place external data at a static position\n"
108		- " -r => mark keys used as 'required' in dtb\n");
	108	+ " -r => mark keys used as 'required' in dtb\n"
	109	+ " -N => engine to use for signing (pkcs11)\n");
109	110	#else
110	111	fprintf(stderr,
111	112	"Signing / verified boot not supported (CONFIG_FIT_SIGNATURE undefined)\n");
...	...	@@ -143,7 +144,7 @@
143	144	int opt;
144	145
145	146	while ((opt = getopt(argc, argv,
146		- "a:A:b:c:C:d:D:e:Ef:Fk:i:K:ln:p:O:rR:qsT:vVx")) != -1) {
	147	+ "a:A:b:c:C:d:D:e:Ef:Fk:i:K:ln:N:p:O:rR:qsT:vVx")) != -1) {
147	148	switch (opt) {
148	149	case 'a':
149	150	params.addr = strtoull(optarg, &ptr, 16);
...	...	@@ -223,6 +224,9 @@
223	224	break;
224	225	case 'n':
225	226	params.imagename = optarg;
	227	+ break;
	228	+ case 'N':
	229	+ params.engine_id = optarg;
226	230	break;
227	231	case 'O':
228	232	params.os = genimg_get_os_id(optarg);