tools/mkeficapsule.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright 2018 Linaro Limited
 *		Author: AKASHI Takahiro
 */

#include <getopt.h>
#include <pe.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <linux/types.h>

#include <sys/stat.h>
#include <sys/types.h>
#include <uuid/uuid.h>
#include <linux/kconfig.h>

#include <gnutls/gnutls.h>
#include <gnutls/pkcs7.h>
#include <gnutls/abstract.h>

#include "eficapsule.h"

static const char *tool_name = "mkeficapsule";

efi_guid_t efi_guid_fm_capsule = EFI_FIRMWARE_MANAGEMENT_CAPSULE_ID_GUID;
efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_GUID;

static const char *opts_short = "g:i:I:v:p:c:m:dh";

static struct option options[] = {
	{"guid", required_argument, NULL, 'g'},
	{"index", required_argument, NULL, 'i'},
	{"instance", required_argument, NULL, 'I'},
	{"private-key", required_argument, NULL, 'p'},
	{"certificate", required_argument, NULL, 'c'},
	{"monotonic-count", required_argument, NULL, 'm'},
	{"dump-sig", no_argument, NULL, 'd'},
	{"help", no_argument, NULL, 'h'},
	{NULL, 0, NULL, 0},
};

static void print_usage(void)
{
	fprintf(stderr, "Usage: %s [options] <image blob> <output file>\n"
		"Options:\n"

		"\t-g, --guid <guid string>    guid for image blob type\n"
		"\t-i, --index <index>         update image index\n"
		"\t-I, --instance <instance>   update hardware instance\n"
		"\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"
		"\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;
	uint8_t *image_data;
	size_t image_size;
	struct efi_firmware_image_authentication auth;
	uint8_t *sig_data;
	size_t sig_size;
};

static int dump_sig;

/**
 * read_bin_file - read a firmware binary file
 * @bin:	Path to a firmware binary file
 * @data:	Pointer to pointer of allocated buffer
 * @bin_size:	Size of allocated buffer
 *
 * Read out a content of binary, @bin, into @data.
 * A caller should free @data.
 *
 * Return:
 * * 0  - on success
 * * -1 - on failure
 */
static int read_bin_file(char *bin, uint8_t **data, off_t *bin_size)
{
	FILE *g;
	struct stat bin_stat;
	void *buf;
	size_t size;
	int ret = 0;

	g = fopen(bin, "r");
	if (!g) {
		fprintf(stderr, "cannot open %s\n", bin);
		return -1;
	}
	if (stat(bin, &bin_stat) < 0) {
		fprintf(stderr, "cannot determine the size of %s\n", bin);
		ret = -1;
		goto err;
	}
	if (bin_stat.st_size > SIZE_MAX) {
		fprintf(stderr, "file size is too large for malloc: %s\n", bin);
		ret = -1;
		goto err;
	}
	buf = malloc(bin_stat.st_size);
	if (!buf) {
		fprintf(stderr, "cannot allocate memory: %zx\n",
			(size_t)bin_stat.st_size);
		ret = -1;
		goto err;
	}

	size = fread(buf, 1, bin_stat.st_size, g);
	if (size < bin_stat.st_size) {
		fprintf(stderr, "read failed (%zx)\n", size);
		ret = -1;
		goto err;
	}

	*data = buf;
	*bin_size = bin_stat.st_size;
err:
	fclose(g);

	return ret;
}

/**
 * write_capsule_file - write a capsule file
 * @bin:	FILE stream
 * @data:	Pointer to data
 * @bin_size:	Size of data
 *
 * Write out data, @data, with the size @bin_size.
 *
 * Return:
 * * 0  - on success
 * * -1 - on failure
 */
static int write_capsule_file(FILE *f, void *data, size_t size, const char *msg)
{
	size_t size_written;

	size_written = fwrite(data, 1, size, f);
	if (size_written < size) {
		fprintf(stderr, "%s: write failed (%zx != %zx)\n", msg,
			size_written, size);
		return -1;
	}

	return 0;
}

/**
 * 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)
{
	gnutls_datum_t cert;
	gnutls_datum_t key;
	off_t file_size;
	gnutls_privkey_t pkey;
	gnutls_x509_crt_t x509;
	gnutls_pkcs7_t pkcs7;
	gnutls_datum_t data;
	gnutls_datum_t signature;
	int ret;

	ret = read_bin_file(ctx->cert_file, &cert.data, &file_size);
	if (ret < 0)
		return -1;
	if (file_size > UINT_MAX)
		return -1;
	cert.size = file_size;

	ret = read_bin_file(ctx->key_file, &key.data, &file_size);
	if (ret < 0)
		return -1;
	if (file_size > UINT_MAX)
		return -1;
	key.size = file_size;

	/*
	 * For debugging,
	 * gnutls_global_set_time_function(mytime);
	 * gnutls_global_set_log_function(tls_log_func);
	 * gnutls_global_set_log_level(6);
	 */

	ret = gnutls_privkey_init(&pkey);
	if (ret < 0) {
		fprintf(stderr, "error in gnutls_privkey_init(): %s\n",
			gnutls_strerror(ret));
		return -1;
	}

	ret = gnutls_x509_crt_init(&x509);
	if (ret < 0) {
		fprintf(stderr, "error in gnutls_x509_crt_init(): %s\n",
			gnutls_strerror(ret));
		return -1;
	}

	/* load a private key */
	ret = gnutls_privkey_import_x509_raw(pkey, &key, GNUTLS_X509_FMT_PEM,
					     0, 0);
	if (ret < 0) {
		fprintf(stderr,
			"error in gnutls_privkey_import_x509_raw(): %s\n",
			gnutls_strerror(ret));
		return -1;
	}

	/* load x509 certificate */
	ret = gnutls_x509_crt_import(x509, &cert, GNUTLS_X509_FMT_PEM);
	if (ret < 0) {
		fprintf(stderr, "error in gnutls_x509_crt_import(): %s\n",
			gnutls_strerror(ret));
		return -1;
	}

	/* generate a PKCS #7 structure */
	ret = gnutls_pkcs7_init(&pkcs7);
	if (ret < 0) {
		fprintf(stderr, "error in gnutls_pkcs7_init(): %s\n",
			gnutls_strerror(ret));
		return -1;
	}

	/* sign */
	/*
	 * Data should have
	 *  * firmware image
	 *  * monotonic count
	 * in this order!
	 * See EDK2's FmpAuthenticatedHandlerRsa2048Sha256()
	 */
	data.size = ctx->image_size + sizeof(ctx->auth.monotonic_count);
	data.data = malloc(data.size);
	if (!data.data) {
		fprintf(stderr, "allocating memory (0x%x) failed\n", data.size);
		return -1;
	}
	memcpy(data.data, ctx->image_data, ctx->image_size);
	memcpy(data.data + ctx->image_size, &ctx->auth.monotonic_count,
	       sizeof(ctx->auth.monotonic_count));

	ret = gnutls_pkcs7_sign(pkcs7, x509, pkey, &data, NULL, NULL,
				GNUTLS_DIG_SHA256,
				/* GNUTLS_PKCS7_EMBED_DATA? */
				GNUTLS_PKCS7_INCLUDE_CERT |
				GNUTLS_PKCS7_INCLUDE_TIME);
	if (ret < 0) {
		fprintf(stderr, "error in gnutls_pkcs7)sign(): %s\n",
			gnutls_strerror(ret));
		return -1;
	}

	/* export */
	ret = gnutls_pkcs7_export2(pkcs7, GNUTLS_X509_FMT_DER, &signature);
	if (ret < 0) {
		fprintf(stderr, "error in gnutls_pkcs7_export2: %s\n",
			gnutls_strerror(ret));
		return -1;
	}
	ctx->sig_data = signature.data;
	ctx->sig_size = signature.size;

	/* 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));

	/*
	 * For better clean-ups,
	 * gnutls_pkcs7_deinit(pkcs7);
	 * gnutls_privkey_deinit(pkey);
	 * gnutls_x509_crt_deinit(x509);
	 * free(cert.data);
	 * free(key.data);
	 * if error
	 *   gnutls_free(signature.data);
	 */

	return 0;
}

/**
 * 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, uint8_t *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)
		gnutls_free(ctx->sig_data);
}

/**
 * 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,
			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;
	uint8_t *data;
	off_t bin_size;
	uint64_t offset;
	int ret;

#ifdef DEBUG
	fprintf(stderr, "For output: %s\n", path);
	fprintf(stderr, "\tbin: %s\n\ttype: %pUl\n", bin, guid);
	fprintf(stderr, "\tindex: %lu\n\tinstance: %lu\n", index, instance);
#endif
	auth_context.sig_size = 0;
	f = NULL;
	data = NULL;
	ret = -1;

	/*
	 * read a firmware binary
	 */
	if (read_bin_file(bin, &data, &bin_size))
		goto err;

	/* 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_size;

		if (create_auth_data(&auth_context)) {
			fprintf(stderr, "Signing firmware image failed\n");
			goto err;
		}

		if (dump_sig &&
		    dump_signature(path, auth_context.sig_data,
				   auth_context.sig_size)) {
			fprintf(stderr, "Creating signature file failed\n");
			goto err;
		}
	}

	/*
	 * write a capsule file
	 */
	f = fopen(path, "w");
	if (!f) {
		fprintf(stderr, "cannot open %s\n", path);
		goto err;
	}

	/*
	 * capsule file header
	 */
	header.capsule_guid = efi_guid_fm_capsule;
	header.header_size = sizeof(header);
	/* TODO: The current implementation ignores flags */
	header.flags = CAPSULE_FLAGS_PERSIST_ACROSS_RESET;
	header.capsule_image_size = sizeof(header)
					+ sizeof(capsule) + sizeof(uint64_t)
					+ sizeof(image)
					+ bin_size;
	if (auth_context.sig_size)
		header.capsule_image_size += sizeof(auth_context.auth)
				+ auth_context.sig_size;
	if (write_capsule_file(f, &header, sizeof(header),
			       "Capsule header"))
		goto err;

	/*
	 * firmware capsule header
	 * This capsule has only one firmware capsule image.
	 */
	capsule.version = 0x00000001;
	capsule.embedded_driver_count = 0;
	capsule.payload_item_count = 1;
	if (write_capsule_file(f, &capsule, sizeof(capsule),
			       "Firmware capsule header"))
		goto err;

	offset = sizeof(capsule) + sizeof(uint64_t);
	if (write_capsule_file(f, &offset, sizeof(offset),
			       "Offset to capsule image"))
		goto err;

	/*
	 * firmware capsule image header
	 */
	image.version = 0x00000003;
	memcpy(&image.update_image_type_id, guid, sizeof(*guid));
	image.update_image_index = index;
	image.reserved[0] = 0;
	image.reserved[1] = 0;
	image.reserved[2] = 0;
	image.update_image_size = bin_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;
	if (write_capsule_file(f, &image, sizeof(image),
			       "Firmware capsule image header"))
		goto err;

	/*
	 * signature
	 */
	if (auth_context.sig_size) {
		if (write_capsule_file(f, &auth_context.auth,
				       sizeof(auth_context.auth),
				       "Authentication header"))
			goto err;

		if (write_capsule_file(f, auth_context.sig_data,
				       auth_context.sig_size, "Signature"))
			goto err;
	}

	/*
	 * firmware binary
	 */
	if (write_capsule_file(f, data, bin_size, "Firmware binary"))
		goto err;

	ret = 0;
err:
	if (f)
		fclose(f);
	free_sig_data(&auth_context);
	free(data);

	return ret;
}

/**
 * convert_uuid_to_guid() - convert UUID to GUID
 * @buf:	UUID binary
 *
 * UUID and GUID have the same data structure, but their binary
 * formats are different due to the endianness. See lib/uuid.c.
 * Since uuid_parse() can handle only UUID, this function must
 * be called to get correct data for GUID when parsing a string.
 *
 * The correct data will be returned in @buf.
 */
void convert_uuid_to_guid(unsigned char *buf)
{
	unsigned char c;

	c = buf[0];
	buf[0] = buf[3];
	buf[3] = c;
	c = buf[1];
	buf[1] = buf[2];
	buf[2] = c;

	c = buf[4];
	buf[4] = buf[5];
	buf[5] = c;

	c = buf[6];
	buf[6] = buf[7];
	buf[7] = c;
}

/**
 * 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)
{
	efi_guid_t *guid;
	unsigned char uuid_buf[16];
	unsigned long index, instance;
	uint64_t mcount;
	char *privkey_file, *cert_file;
	int c, idx;

	guid = NULL;
	index = 0;
	instance = 0;
	mcount = 0;
	privkey_file = NULL;
	cert_file = NULL;
	dump_sig = 0;
	for (;;) {
		c = getopt_long(argc, argv, opts_short, options, &idx);
		if (c == -1)
			break;

		switch (c) {
		case 'g':
			if (guid) {
				fprintf(stderr,
					"Image type already specified\n");
				exit(EXIT_FAILURE);
			}
			if (uuid_parse(optarg, uuid_buf)) {
				fprintf(stderr, "Wrong guid format\n");
				exit(EXIT_FAILURE);
			}
			convert_uuid_to_guid(uuid_buf);
			guid = (efi_guid_t *)uuid_buf;
			break;
		case 'i':
			index = strtoul(optarg, NULL, 0);
			break;
		case 'I':
			instance = strtoul(optarg, NULL, 0);
			break;
		case 'p':
			if (privkey_file) {
				fprintf(stderr,
					"Private Key already specified\n");
				exit(EXIT_FAILURE);
			}
			privkey_file = optarg;
			break;
		case 'c':
			if (cert_file) {
				fprintf(stderr,
					"Certificate file already specified\n");
				exit(EXIT_FAILURE);
			}
			cert_file = optarg;
			break;
		case 'm':
			mcount = strtoul(optarg, NULL, 0);
			break;
		case 'd':
			dump_sig = 1;
			break;
		case 'h':
			print_usage();
			exit(EXIT_SUCCESS);
		}
	}

	/* check necessary parameters */
	if ((argc != optind + 2) || !guid ||
	    ((privkey_file && !cert_file) ||
	     (!privkey_file && cert_file))) {
		print_usage();
		exit(EXIT_FAILURE);
	}

	if (create_fwbin(argv[argc - 1], argv[argc - 2], guid, index, instance,
			 mcount, privkey_file, cert_file) < 0) {
		fprintf(stderr, "Creating firmware capsule failed\n");
		exit(EXIT_FAILURE);
	}

	exit(EXIT_SUCCESS);
}