[PATCH v5 02/11] tools: mkeficapsule: add firmwware image signing

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

With this enhancement, mkeficapsule will be able to sign a capsule
file when it is created. A signature added will be used later
in the verification at FMP's SetImage() call.

To do that, We need specify additional command parameters:
  -monotonic-cout <count> : monotonic count
  -private-key <private key file> : private key file
  -certificate <certificate file> : certificate file
Only when all of those parameters are given, a signature will be added
to a capsule file.

Users are expected to maintain and increment the monotonic count at
every time of the update for each firmware image.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 tools/Kconfig        |   8 +
 tools/Makefile       |   8 +-
 tools/mkeficapsule.c | 435 +++++++++++++++++++++++++++++++++++++++----
 3 files changed, 417 insertions(+), 34 deletions(-)

diff --git a/tools/Kconfig b/tools/Kconfig
index 91ce8ae3e516..117c921da3fe 100644
--- a/tools/Kconfig
+++ b/tools/Kconfig
@@ -90,4 +90,12 @@ config TOOLS_SHA512
 	help
 	  Enable SHA512 support in the tools builds
 
+config TOOLS_MKEFICAPSULE
+	bool "Build efimkcapsule command"
+	default y if EFI_CAPSULE_ON_DISK
+	help
+	  This command allows users to create a UEFI capsule file and,
+	  optionally sign that file. If you want to enable UEFI capsule
+	  update feature on your target, you certainly need this.
+
 endmenu
diff --git a/tools/Makefile b/tools/Makefile
index b45219e2c30c..5a73cc4b363d 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -238,8 +238,12 @@ hostprogs-$(CONFIG_MIPS) += mips-relocs
 hostprogs-$(CONFIG_ASN1_COMPILER)	+= asn1_compiler
 HOSTCFLAGS_asn1_compiler.o = -idirafter $(srctree)/include
 
-mkeficapsule-objs	:= mkeficapsule.o $(LIBFDT_OBJS)
-hostprogs-$(CONFIG_EFI_HAVE_CAPSULE_SUPPORT) += mkeficapsule
+HOSTLDLIBS_mkeficapsule += -luuid
+ifeq ($(CONFIG_TOOLS_LIBCRYPTO),y)
+HOSTLDLIBS_mkeficapsule += \
+	$(shell pkg-config --libs libssl libcrypto 2> /dev/null || echo "-lssl -lcrypto")
+endif
+hostprogs-$(CONFIG_TOOLS_MKEFICAPSULE) += mkeficapsule
 
 # We build some files with extra pedantic flags to try to minimize things
 # that won't build on some weird host compiler -- though there are lots of
diff --git a/tools/mkeficapsule.c b/tools/mkeficapsule.c
index 4995ba4e0c2a..5541e4bda894 100644
--- a/tools/mkeficapsule.c
+++ b/tools/mkeficapsule.c
@@ -15,6 +15,16 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
+#include <linux/kconfig.h>
+#ifdef CONFIG_TOOLS_LIBCRYPTO
+#include <openssl/asn1.h>
+#include <openssl/bio.h>
+#include <openssl/evp.h>
+#include <openssl/err.h>
+#include <openssl/pem.h>
+#include <openssl/pkcs7.h>
+#endif
+
 typedef __u8 u8;
 typedef __u16 u16;
 typedef __u32 u32;
@@ -38,12 +48,25 @@ efi_guid_t efi_guid_image_type_uboot_fit =
 		EFI_FIRMWARE_IMAGE_TYPE_UBOOT_FIT_GUID;
 efi_guid_t efi_guid_image_type_uboot_raw =
 		EFI_FIRMWARE_IMAGE_TYPE_UBOOT_RAW_GUID;
+efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_GUID;
+
+#ifdef CONFIG_TOOLS_LIBCRYPTO
+static const char *opts_short = "f:r:i:I:v:p:c:m:dh";
+#else
+static const char *opts_short = "f:r:i:I:v:h";
+#endif
 
 static struct option options[] = {
 	{"fit", required_argument, NULL, 'f'},
 	{"raw", required_argument, NULL, 'r'},
 	{"index", required_argument, NULL, 'i'},
 	{"instance", required_argument, NULL, 'I'},
+#ifdef CONFIG_TOOLS_LIBCRYPTO
+	{"private-key", required_argument, NULL, 'p'},
+	{"certificate", required_argument, NULL, 'c'},
+	{"monotonic-count", required_argument, NULL, 'm'},
+	{"dump-sig", no_argument, NULL, 'd'},
+#endif
 	{"help", no_argument, NULL, 'h'},
 	{NULL, 0, NULL, 0},
 };
@@ -57,16 +80,280 @@ static void print_usage(void)
 	       "\t-r, --raw <raw image>       new raw image file\n"
 	       "\t-i, --index <index>         update image index\n"
 	       "\t-I, --instance <instance>   update hardware instance\n"
+#ifdef CONFIG_TOOLS_LIBCRYPTO
+	       "\t-p, --private-key <privkey file>  private key file\n"
+	       "\t-c, --certificate <cert file>     signer's certificate file\n"
+	       "\t-m, --monotonic-count <count>     monotonic count\n"
+	       "\t-d, --dump_sig              dump signature (*.p7)\n"
+#endif
 	       "\t-h, --help                  print a help message\n",
 	       tool_name);
 }
 
+/**
+ * auth_context - authentication context
+ * @key_file:	Path to a private key file
+ * @cert_file:	Path to a certificate file
+ * @image_data:	Pointer to firmware data
+ * @image_size:	Size of firmware data
+ * @auth:	Authentication header
+ * @sig_data:	Signature data
+ * @sig_size:	Size of signature data
+ *
+ * Data structure used in create_auth_data(). @key_file through
+ * @image_size are input parameters. @auth, @sig_data and @sig_size
+ * are filled in by create_auth_data().
+ */
+struct auth_context {
+	char *key_file;
+	char *cert_file;
+	u8 *image_data;
+	size_t image_size;
+	struct efi_firmware_image_authentication auth;
+	u8 *sig_data;
+	size_t sig_size;
+};
+
+static int dump_sig;
+
+#ifdef CONFIG_TOOLS_LIBCRYPTO
+/**
+ * fileio-read_pkey - read out a private key
+ * @filename:	Path to a private key file
+ *
+ * Read out a private key file and parse it into "EVP_PKEY" structure.
+ *
+ * Return:
+ * * Pointer to private key structure  - on success
+ * * NULL - on failure
+ */
+static EVP_PKEY *fileio_read_pkey(const char *filename)
+{
+	EVP_PKEY *key = NULL;
+	BIO *bio;
+
+	bio = BIO_new_file(filename, "r");
+	if (!bio)
+		goto out;
+
+	key = PEM_read_bio_PrivateKey(bio, NULL, NULL, NULL);
+
+out:
+	BIO_free_all(bio);
+	if (!key) {
+		printf("Can't load key from file '%s'\n", filename);
+		ERR_print_errors_fp(stderr);
+	}
+
+	return key;
+}
+
+/**
+ * fileio-read_cert - read out a certificate
+ * @filename:	Path to a certificate file
+ *
+ * Read out a certificate file and parse it into "X509" structure.
+ *
+ * Return:
+ * * Pointer to certificate structure  - on success
+ * * NULL - on failure
+ */
+static X509 *fileio_read_cert(const char *filename)
+{
+	X509 *cert = NULL;
+	BIO *bio;
+
+	bio = BIO_new_file(filename, "r");
+	if (!bio)
+		goto out;
+
+	cert = PEM_read_bio_X509(bio, NULL, NULL, NULL);
+
+out:
+	BIO_free_all(bio);
+	if (!cert) {
+		printf("Can't load certificate from file '%s'\n", filename);
+		ERR_print_errors_fp(stderr);
+	}
+
+	return cert;
+}
+
+/**
+ * create_auth_data - compose authentication data in capsule
+ * @auth_context:	Pointer to authentication context
+ *
+ * Fill up an authentication header (.auth) and signature data (.sig_data)
+ * in @auth_context, using library functions from openssl.
+ * All the parameters in @auth_context must be filled in by a caller.
+ *
+ * Return:
+ * * 0  - on success
+ * * -1 - on failure
+ */
+static int create_auth_data(struct auth_context *ctx)
+{
+	EVP_PKEY *key = NULL;
+	X509 *cert = NULL;
+	BIO *data_bio = NULL;
+	const EVP_MD *md;
+	PKCS7 *p7;
+	int flags, ret = -1;
+
+	OpenSSL_add_all_digests();
+	OpenSSL_add_all_ciphers();
+	ERR_load_crypto_strings();
+
+	key = fileio_read_pkey(ctx->key_file);
+	if (!key)
+		goto err;
+	cert = fileio_read_cert(ctx->cert_file);
+	if (!cert)
+		goto err;
+
+	/*
+	 * create a BIO, containing:
+	 *  * firmware image
+	 *  * monotonic count
+	 * in this order!
+	 * See EDK2's FmpAuthenticatedHandlerRsa2048Sha256()
+	 */
+	data_bio = BIO_new(BIO_s_mem());
+	BIO_write(data_bio, ctx->image_data, ctx->image_size);
+	BIO_write(data_bio, &ctx->auth.monotonic_count,
+		  sizeof(ctx->auth.monotonic_count));
+
+	md = EVP_get_digestbyname("SHA256");
+	if (!md)
+		goto err;
+
+	/* create signature */
+	/* TODO: maybe add PKCS7_NOATTR and PKCS7_NOSMIMECAP */
+	flags = PKCS7_BINARY | PKCS7_DETACHED;
+	p7 = PKCS7_sign(NULL, NULL, NULL, data_bio, flags | PKCS7_PARTIAL);
+	if (!p7)
+		goto err;
+	if (!PKCS7_sign_add_signer(p7, cert, key, md, flags))
+		goto err;
+	if (!PKCS7_final(p7, data_bio, flags))
+		goto err;
+
+	/* convert pkcs7 into DER */
+	ctx->sig_data = NULL;
+	ctx->sig_size = ASN1_item_i2d((ASN1_VALUE *)p7, &ctx->sig_data,
+				      ASN1_ITEM_rptr(PKCS7));
+	if (!ctx->sig_size)
+		goto err;
+
+	/* fill auth_info */
+	ctx->auth.auth_info.hdr.dwLength = sizeof(ctx->auth.auth_info)
+						+ ctx->sig_size;
+	ctx->auth.auth_info.hdr.wRevision = WIN_CERT_REVISION_2_0;
+	ctx->auth.auth_info.hdr.wCertificateType = WIN_CERT_TYPE_EFI_GUID;
+	memcpy(&ctx->auth.auth_info.cert_type, &efi_guid_cert_type_pkcs7,
+	       sizeof(efi_guid_cert_type_pkcs7));
+
+	ret = 0;
+err:
+	BIO_free_all(data_bio);
+	EVP_PKEY_free(key);
+	X509_free(cert);
+
+	return ret;
+}
+
+/**
+ * dump_signature - dump out a signature
+ * @path:	Path to a capsule file
+ * @signature:	Signature data
+ * @sig_size:	Size of signature data
+ *
+ * Signature data pointed to by @signature will be saved into
+ * a file whose file name is @path with ".p7" suffix.
+ *
+ * Return:
+ * * 0  - on success
+ * * -1 - on failure
+ */
+static int dump_signature(const char *path, u8 *signature, size_t sig_size)
+{
+	char *sig_path;
+	FILE *f;
+	size_t size;
+	int ret = -1;
+
+	sig_path = malloc(strlen(path) + 3 + 1);
+	if (!sig_path)
+		return ret;
+
+	sprintf(sig_path, "%s.p7", path);
+	f = fopen(sig_path, "w");
+	if (!f)
+		goto err;
+
+	size = fwrite(signature, 1, sig_size, f);
+	if (size == sig_size)
+		ret = 0;
+
+	fclose(f);
+err:
+	free(sig_path);
+	return ret;
+}
+
+/**
+ * free_sig_data - free out signature data
+ * @ctx:	Pointer to authentication context
+ *
+ * Free signature data allocated in create_auth_data().
+ */
+static void free_sig_data(struct auth_context *ctx)
+{
+	if (ctx->sig_size)
+		OPENSSL_free(ctx->sig_data);
+}
+#else
+static int create_auth_data(struct auth_context *ctx)
+{
+	return 0;
+}
+
+static int dump_signature(const char *path, u8 *signature, size_t sig_size)
+{
+	return 0;
+}
+
+static void free_sig_data(struct auth_context *ctx) {}
+#endif
+
+/**
+ * create_fwbin - create an uefi capsule file
+ * @path:	Path to a created capsule file
+ * @bin:	Path to a firmware binary to encapsulate
+ * @guid:	GUID of related FMP driver
+ * @index:	Index number in capsule
+ * @instance:	Instance number in capsule
+ * @mcount:	Monotonic count in authentication information
+ * @private_file:	Path to a private key file
+ * @cert_file:	Path to a certificate file
+ *
+ * This function actually does the job of creating an uefi capsule file.
+ * All the arguments must be supplied.
+ * If either @private_file ror @cert_file is NULL, the capsule file
+ * won't be signed.
+ *
+ * Return:
+ * * 0  - on success
+ * * -1 - on failure
+ */
 static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
-			unsigned long index, unsigned long instance)
+			unsigned long index, unsigned long instance,
+			uint64_t mcount, char *privkey_file, char *cert_file)
 {
 	struct efi_capsule_header header;
 	struct efi_firmware_management_capsule_header capsule;
 	struct efi_firmware_management_capsule_image_header image;
+	struct auth_context auth_context;
 	FILE *f, *g;
 	struct stat bin_stat;
 	u8 *data;
@@ -76,8 +363,9 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
 #ifdef DEBUG
 	printf("For output: %s\n", path);
 	printf("\tbin: %s\n\ttype: %pUl\n", bin, guid);
-	printf("\tindex: %ld\n\tinstance: %ld\n", index, instance);
+	printf("\tindex: %lu\n\tinstance: %lu\n", index, instance);
 #endif
+	auth_context.sig_size = 0;
 
 	g = fopen(bin, "r");
 	if (!g) {
@@ -93,11 +381,34 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
 		printf("cannot allocate memory: %zx\n", (size_t)bin_stat.st_size);
 		goto err_1;
 	}
-	f = fopen(path, "w");
-	if (!f) {
-		printf("cannot open %s\n", path);
+
+	size = fread(data, 1, bin_stat.st_size, g);
+	if (size < bin_stat.st_size) {
+		printf("read failed (%zx)\n", size);
 		goto err_2;
 	}
+
+	/* first, calculate signature to determine its size */
+	if (privkey_file && cert_file) {
+		auth_context.key_file = privkey_file;
+		auth_context.cert_file = cert_file;
+		auth_context.auth.monotonic_count = mcount;
+		auth_context.image_data = data;
+		auth_context.image_size = bin_stat.st_size;
+
+		if (create_auth_data(&auth_context)) {
+			printf("Signing firmware image failed\n");
+			goto err_3;
+		}
+
+		if (dump_sig &&
+		    dump_signature(path, auth_context.sig_data,
+				   auth_context.sig_size)) {
+			printf("Creating signature file failed\n");
+			goto err_3;
+		}
+	}
+
 	header.capsule_guid = efi_guid_fm_capsule;
 	header.header_size = sizeof(header);
 	/* TODO: The current implementation ignores flags */
@@ -106,11 +417,20 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
 					+ sizeof(capsule) + sizeof(u64)
 					+ sizeof(image)
 					+ bin_stat.st_size;
+	if (auth_context.sig_size)
+		header.capsule_image_size += sizeof(auth_context.auth)
+				+ auth_context.sig_size;
+
+	f = fopen(path, "w");
+	if (!f) {
+		printf("cannot open %s\n", path);
+		goto err_3;
+	}
 
 	size = fwrite(&header, 1, sizeof(header), f);
 	if (size < sizeof(header)) {
 		printf("write failed (%zx)\n", size);
-		goto err_3;
+		goto err_4;
 	}
 
 	capsule.version = 0x00000001;
@@ -119,13 +439,13 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
 	size = fwrite(&capsule, 1, sizeof(capsule), f);
 	if (size < (sizeof(capsule))) {
 		printf("write failed (%zx)\n", size);
-		goto err_3;
+		goto err_4;
 	}
 	offset = sizeof(capsule) + sizeof(u64);
 	size = fwrite(&offset, 1, sizeof(offset), f);
 	if (size < sizeof(offset)) {
 		printf("write failed (%zx)\n", size);
-		goto err_3;
+		goto err_4;
 	}
 
 	image.version = 0x00000003;
@@ -135,34 +455,53 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
 	image.reserved[1] = 0;
 	image.reserved[2] = 0;
 	image.update_image_size = bin_stat.st_size;
+	if (auth_context.sig_size)
+		image.update_image_size += sizeof(auth_context.auth)
+				+ auth_context.sig_size;
 	image.update_vendor_code_size = 0; /* none */
 	image.update_hardware_instance = instance;
 	image.image_capsule_support = 0;
+	if (auth_context.sig_size)
+		image.image_capsule_support |= CAPSULE_SUPPORT_AUTHENTICATION;
 
 	size = fwrite(&image, 1, sizeof(image), f);
 	if (size < sizeof(image)) {
 		printf("write failed (%zx)\n", size);
-		goto err_3;
+		goto err_4;
 	}
-	size = fread(data, 1, bin_stat.st_size, g);
-	if (size < bin_stat.st_size) {
-		printf("read failed (%zx)\n", size);
-		goto err_3;
+
+	if (auth_context.sig_size) {
+		size = fwrite(&auth_context.auth, 1,
+			      sizeof(auth_context.auth), f);
+		if (size < sizeof(auth_context.auth)) {
+			printf("write failed (%zx)\n", size);
+			goto err_4;
+		}
+		size = fwrite(auth_context.sig_data, 1,
+			      auth_context.sig_size, f);
+		if (size < auth_context.sig_size) {
+			printf("write failed (%zx)\n", size);
+			goto err_4;
+		}
 	}
+
 	size = fwrite(data, 1, bin_stat.st_size, f);
 	if (size < bin_stat.st_size) {
 		printf("write failed (%zx)\n", size);
-		goto err_3;
+		goto err_4;
 	}
 
 	fclose(f);
 	fclose(g);
 	free(data);
+	free_sig_data(&auth_context);
 
 	return 0;
 
-err_3:
+err_4:
 	fclose(f);
+err_3:
+	free_sig_data(&auth_context);
 err_2:
 	free(data);
 err_1:
@@ -171,23 +510,37 @@ err_1:
 	return -1;
 }
 
-/*
- * Usage:
- *   $ mkeficapsule -f <firmware binary> <output file>
+/**
+ * main - main entry function of mkeficapsule
+ * @argc:	Number of arguments
+ * @argv:	Array of pointers to arguments
+ *
+ * Create an uefi capsule file, optionally signing it.
+ * Parse all the arguments and pass them on to create_fwbin().
+ *
+ * Return:
+ * * 0  - on success
+ * * -1 - on failure
  */
 int main(int argc, char **argv)
 {
 	char *file;
 	efi_guid_t *guid;
 	unsigned long index, instance;
+	uint64_t mcount;
+	char *privkey_file, *cert_file;
 	int c, idx;
 
 	file = NULL;
 	guid = NULL;
 	index = 0;
 	instance = 0;
+	mcount = 0;
+	privkey_file = NULL;
+	cert_file = NULL;
+	dump_sig = 0;
 	for (;;) {
-		c = getopt_long(argc, argv, "f:r:i:I:v:h", options, &idx);
+		c = getopt_long(argc, argv, opts_short, options, &idx);
 		if (c == -1)
 			break;
 
@@ -214,29 +567,47 @@ int main(int argc, char **argv)
 		case 'I':
 			instance = strtoul(optarg, NULL, 0);
 			break;
+#ifdef CONFIG_TOOLS_LIBCRYPTO
+		case 'p':
+			if (privkey_file) {
+				printf("Private Key already specified\n");
+				return -1;
+			}
+			privkey_file = optarg;
+			break;
+		case 'c':
+			if (cert_file) {
+				printf("Certificate file already specified\n");
+				return -1;
+			}
+			cert_file = optarg;
+			break;
+		case 'm':
+			mcount = strtoul(optarg, NULL, 0);
+			break;
+		case 'd':
+			dump_sig = 1;
+			break;
+#endif /* CONFIG_TOOLS_LIBCRYPTO */
 		case 'h':
 			print_usage();
 			return 0;
 		}
 	}
 
-	/* need an output file */
-	if (argc != optind + 1) {
-		print_usage();
-		exit(EXIT_FAILURE);
-	}
-
-	/* need a fit image file or raw image file */
-	if (!file) {
+	/* check necessary parameters */
+	if ((argc != optind + 1) || !file ||
+	    ((privkey_file && !cert_file) ||
+	     (!privkey_file && cert_file))) {
 		print_usage();
-		exit(EXIT_SUCCESS);
+		return -1;
 	}
 
-	if (create_fwbin(argv[optind], file, guid, index, instance)
-			< 0) {
+	if (create_fwbin(argv[optind], file, guid, index, instance,
+			 mcount, privkey_file, cert_file) < 0) {
 		printf("Creating firmware capsule failed\n");
-		exit(EXIT_FAILURE);
+		return -1;
 	}
 
-	exit(EXIT_SUCCESS);
+	return 0;
 }
-- 
2.33.0