[PATCH v2 1/9] tools: mkeficapsule: add firmwware image signing
AKASHI Takahiro
takahiro.akashi at linaro.org
Mon Aug 2 08:55:05 CEST 2021
On Mon, Aug 02, 2021 at 08:18:37AM +0200, Heinrich Schuchardt wrote:
>
>
> 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 += \
> > > > + $(shell pkg-config --libs libssl libcrypto 2> /dev/null || echo "-lssl -lcrypto")
> > >
> > > Please, add package pkg-config to the build dependencies enumerated in
> > > doc/build/gcc.rst.
> >
> > Already there: libssl-dev
>
> It is *pkg-config* that is missing.
OK, I see what you mean.
But this use is not quite new as the first appearance of
pkg-config was found in the commit 4839836a124e
Author: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
Date: Sat May 16 18:36:15 2015 +0200
tools: use pkg-config when available to get SSL flags
So a separate patch would be appropriate.
-Takahiro Akashi
> >
> > > > +endif
> > > > +hostprogs-$(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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