Re: [PATCH v3 1/5] tools: mkeficapsule: add firmwware image signing

On 8/31/21 4:46 AM, AKASHI Takahiro wrote:

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:

nits

%s/need/need to/

-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

%s/at//

every time of the update for each firmware image.

Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org

tools/Kconfig | 7 + tools/Makefile | 8 +- tools/mkeficapsule.c | 435 +++++++++++++++++++++++++++++++++++++++---- 3 files changed, 416 insertions(+), 34 deletions(-)

diff --git a/tools/Kconfig b/tools/Kconfig index d6f82cd949b5..9a37ed035311 100644 --- a/tools/Kconfig +++ b/tools/Kconfig @@ -20,4 +20,11 @@ config TOOLS_LIBCRYPTO This selection does not affect target features, such as runtime FIT signature verification.

+config TOOLS_MKEFICAPSULE

• bool "Build efimkcapsule command"

Having different versions of efimkcapsule with different capabilities is very confusing for users.

Please, add

select TOOLS_LIBCRYPTO

• 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 4a86321f6467..6ea3033dbfb8 100644 --- a/tools/Makefile +++ b/tools/Makefile @@ -237,8 +237,12 @@ 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..090fb02de68d 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

If I get you right, you ideentified two use cases:

* unsigned capsules * signed capsules

Should it be allowable to have unsigned capsules with some board configurations then mkeficapsule compiled with CONFIG_TOOLS_LIBCRYPTO=y must be able to produce unsigned capsules.

{"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: Monolitic 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 ||

This needs to be changed to support signed and unsigned capsules.

•    ((privkey_file && !cert_file) ||
  

•     (!privkey_file && cert_file))) {
  

  print_usage();

• exit(EXIT_SUCCESS);
  

• return -1;
  

Please use EXIT_FALURE.

}

• 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;
  

return EXIT_FAILURE;

}

• exit(EXIT_SUCCESS);

• return 0;

In main, please, use

return EXIT_SUCCESS;

Best regards

Heinrich

}