[PATCH v2 1/9] tools: mkeficapsule: add firmwware image signing
Heinrich Schuchardt
xypron.glpk at gmx.de
Mon Aug 2 08:18:37 CEST 2021
On 8/2/21 5:30 AM, AKASHI Takahiro wrote:
> Heinrich,
>
> On Sun, Aug 01, 2021 at 11:21:55AM +0200, Heinrich Schuchardt wrote:
>> On 7/27/21 11:10 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:
>>> -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 at linaro.org>
>>> ---
>>> tools/Kconfig | 7 +
>>> tools/Makefile | 8 +-
>>> tools/mkeficapsule.c | 332 +++++++++++++++++++++++++++++++++++++++----
>>> 3 files changed, 316 insertions(+), 31 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"
>>> + 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 bae3f95c4995..af8536489652 100644
>>> --- a/tools/Makefile
>>> +++ b/tools/Makefile
>>> @@ -245,8 +245,12 @@ 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 += \
>>> + $(shell pkg-config --libs libssl libcrypto 2> /dev/null || echo "-lssl -lcrypto")
>>
>> Please, add package pkg-config to the build dependencies enumerated in
>> doc/build/gcc.rst.
>
> Already there: libssl-dev
It is *pkg-config* that is missing.
>
>>> +endif
>>> +hostprogs-$(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..798706c7b5f7 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 +80,195 @@ 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);
>>> }
>>>
>>
>> Please, add Sphinx documentation.
>
> I added the man page. Why need another different format of doc?
> I think that doc/develop/uefi/uefi.rst gives you an enough
> introduction to the command.
> (Although the doc will have to been updated due to the latest change
> of mkeficapsule syntax that I'm also proposing.)
>
> Actually, there is no sphinx doc for any host tools.
>
>>> +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
>>> +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;
>>> +}
>>> +
>>
>> Please, add Sphinx documentation for all functions.
>
> Yeah, but "all" is a too forcible requirement.
> There is no source code of host tools to meet the requirement.
> Actually, most don't have even one description of a function.
>
> I think that, if it is a really required element in the source,
> it should be explicitly described somewhere under "doc".
>
>>> +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;
>>> +}
>>> +
>>> +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;
>>> +}
>>> +
>>> +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;
>>> +}
>>> +
>>> +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
>>> +
>>> 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;
>>> @@ -78,6 +280,7 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
>>> printf("\tbin: %s\n\ttype: %pUl\n", bin, guid);
>>> printf("\tindex: %ld\n\tinstance: %ld\n", index, instance);
>>
>> [tools/mkeficapsule.c:281] (warning) %ld in format string (no. 1)
>> requires 'long' but the argument type is 'unsigned long'.
>
> Will fix it.
>
> -Takahiro Akashi
>
>
>> Best regards
>>
>> Heinrich
>>
>>> #endif
>>> + auth_context.sig_size = 0;
>>>
>>> g = fopen(bin, "r");
>>> if (!g) {
>>> @@ -93,11 +296,34 @@ 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 +332,20 @@ 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 +354,13 @@ 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 +370,53 @@ 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 +425,25 @@ err_1:
>>> return -1;
>>> }
>>>
>>> -/*
>>> - * Usage:
>>> - * $ mkeficapsule -f <firmware binary> <output file>
>>> - */
>>> 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;
>>>
>>> @@ -214,26 +470,44 @@ 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) {
>>> + /* check necessary parameters */
>>> + if ((argc != optind + 1) || !file ||
>>> + ((privkey_file && !cert_file) ||
>>> + (!privkey_file && cert_file))) {
>>> print_usage();
>>> exit(EXIT_FAILURE);
>>> }
>>>
>>> - /* need a fit image file or raw image file */
>>> - if (!file) {
>>> - print_usage();
>>> - exit(EXIT_SUCCESS);
>>> - }
>>> -
>>> - 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);
>>> }
>>>
>>
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