On Thu, May 13, 2021 at 08:55:17AM +0200, Heinrich Schuchardt wrote:
Am 13. Mai 2021 08:50:54 MESZ schrieb AKASHI Takahiro takahiro.akashi@linaro.org:
On Thu, May 13, 2021 at 07:50:52AM +0200, Heinrich Schuchardt wrote:
On 5/13/21 7:12 AM, Masami Hiramatsu wrote:
Hi Heinrich,
2021年5月13日(木) 13:22 Heinrich Schuchardt xypron.glpk@gmx.de:
On 5/13/21 5:08 AM, AKASHI Takahiro wrote:
On Wed, May 12, 2021 at 10:56:41AM +0200, Heinrich Schuchardt
wrote:
> On 12.05.21 06:57, AKASHI Takahiro wrote: > > With this enhancement, mkeficapsule will be able to create
a capsule
> > file with a signature which will be verified later by FMP's
SetImage().
> > > > We will have to specify addtional command parameters: > > -monotonic-cout <count> : monotonic count > > -private-key <private key file> : private key file > > -certificate <certificate file> : certificate file > > Only when those parameters are given, a signature will be
added
> > to a capsule file. > > > > Users are expected to maintain the monotonic count for each
firmware
> > image. > > > > Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org > > --- > > tools/Makefile | 4 + > > tools/mkeficapsule.c | 324
+++++++++++++++++++++++++++++++++++++++----
> > 2 files changed, 303 insertions(+), 25 deletions(-) > > > > diff --git a/tools/Makefile b/tools/Makefile > > index d020c55d6644..02eae0286e20 100644 > > --- a/tools/Makefile > > +++ b/tools/Makefile > > @@ -231,6 +231,10 @@ hostprogs-$(CONFIG_MIPS) +=
mips-relocs
> > hostprogs-$(CONFIG_ASN1_COMPILER) += asn1_compiler > > HOSTCFLAGS_asn1_compiler.o = -idirafter
$(srctree)/include
> > > > +ifneq ($(CONFIG_EFI_CAPSULE_AUTHENTICATE),) > > +HOSTLDLIBS_mkeficapsule += \ > > + $(shell pkg-config --libs libssl libcrypto 2> /dev/null
|| echo "-lssl -lcrypto")
> > I don't expect any user wants to install two tool versions in
parallel.
> > The tool should always be able to add a signature. > Adding a signature must be optional.
It seems to me that those two statements mutually contradict. Or do you intend to say that we should have a separate kconfig option to enable/disable signing feature in mkeficapsule?
If so, I can agree.
In either way, we should have an option to turn on/off this
functionality
as not all users use signed capsules.
I want to have a single binary to distribute with Linux distros
(e.g.
Debian/Ubuntu package u-boot-tools).
I couldn't catch your point. If so, the distros can build u-boot
with
CONFIG_EFI_CAPSULE_AUTHENTICATE=y...
Why should the tool depend on board configuration? Who would want capsule updates without authentication?
I believe that there are bunch of users who don't need authentication on their own systems.
They should think again.
Why?
BTW, IMHO, if u-boot.bin can not find the ESL in the device tree, it should skip authentication too.
In this case the capsule should be rejected (if CONFIG_EFI_CAPSULE_AUTHENTICATE=y).
That's basically right. But as I mentioned in my comment against Sughosh's patch, the authentication process will be enforced only if the capsule has an attribute, IMAGE_ATTRIBUTE_AUTHENTICATION_REQUIRED.
That would be a security desaster.
The requirement that I mentioned above is clearly described in UEFI specification. If you think that it is a disaster, please discuss the topic in UEFI Forum first.
-Takahiro Akashi
Best regards
Heinrich
I believe that this flag should be able to be specified and managed outside U-Boot configuration. So there can be a case where FW update is performed even if the key/certificate is not found in the device tree.
Then, user can choose whether enabling capsule authentication or
not
by embedding ESL into their devicetree.
Same comment above.
-Takahiro Akashi
The user shall not be able to decide anything that might hamper security. The U-Boot binary must dictate if a capsule is safe.
Best regards
Heinrich
Thank you
This should allow both
- create signed capsules
- create unsigned capsules
The user shall select signing via command line parameters.
Support for signing via the tool shall not depend on board
Kconfig
parameters.
Best regards
Heinrich
> > +endif > > mkeficapsule-objs := mkeficapsule.o $(LIBFDT_OBJS) > > hostprogs-$(CONFIG_EFI_HAVE_CAPSULE_SUPPORT) +=
mkeficapsule
> > > > diff --git a/tools/mkeficapsule.c b/tools/mkeficapsule.c > > index de0a62898886..34ff1bdd82eb 100644 > > --- a/tools/mkeficapsule.c > > +++ b/tools/mkeficapsule.c > > @@ -18,7 +18,17 @@ > > #include <sys/stat.h> > > #include <sys/types.h> > > > > -#include "fdt_host.h" > > +#include <linux/kconfig.h> > > +#if IS_ENABLED(CONFIG_EFI_CAPSULE_AUTHENTICATE) > > see above > > > +#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 > > + > > +#include <linux/libfdt.h> > > > > typedef __u8 u8; > > typedef __u16 u16; > > @@ -46,6 +56,13 @@ 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;
> > + > > +#if IS_ENABLED(CONFIG_EFI_CAPSULE_AUTHENTICATE) > > see above > > > +static const char *opts_short = "f:r:i:I:v:D:K:P:C:m:dOh"; > > +#else > > +static const char *opts_short = "f:r:i:I:v:D:K:Oh"; > > +#endif > > > > static struct option options[] = { > > {"fit", required_argument, NULL, 'f'}, > > @@ -54,6 +71,12 @@ static struct option options[] = { > > {"instance", required_argument, NULL, 'I'}, > > {"dtb", required_argument, NULL, 'D'}, > > {"public key", required_argument, NULL, 'K'}, > > +#if IS_ENABLED(CONFIG_EFI_CAPSULE_AUTHENTICATE) > > + {"private-key", required_argument, NULL, 'P'}, > > + {"certificate", required_argument, NULL, 'C'}, > > + {"monotonic-count", required_argument, NULL, 'm'}, > > These options should not be required.
I don't get you. What do you mean?
> > + {"dump-sig", no_argument, NULL, 'd'}, > > +#endif > > {"overlay", no_argument, NULL, 'O'}, > > {"help", no_argument, NULL, 'h'}, > > {NULL, 0, NULL, 0}, > > @@ -70,6 +93,12 @@ static void print_usage(void) > > "\t-I, --instance <instance> update hardware
instance\n"
> > "\t-K, --public-key <key file> public key esl
file\n"
> > "\t-D, --dtb <dtb file> dtb file\n" > > +#if IS_ENABLED(CONFIG_EFI_CAPSULE_AUTHENTICATE) > > see above > > > + "\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-O, --overlay the dtb file is
an overlay\n"
> > "\t-h, --help print a help
message\n",
> > tool_name); > > @@ -249,12 +278,167 @@ err: > > return ret; > > } > > > > +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; > > + > > +#if IS_ENABLED(CONFIG_EFI_CAPSULE_AUTHENTICATE) > > see above > > > +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);
> > Please, you use fprintf(stderr,) for error messages. > > > + ERR_print_errors_fp(stderr); > > + } > > + > > + return key; > > +} > > + > > +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);
> > fprintf(stderr,) > > > + 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 */ > > PKCS7_NOATTR is a value without any documentation in the
code.
Nak. Those macros are part of openssl library. See openssl/pkcs7.h.
> Please, replace variable names by a long text describing what
it missing.
> > > + flags = PKCS7_BINARY | PKCS7_DETACHED; > > Those constants lack documentation in the code.
Nak again.
> > + 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; > > +} > > +#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; > > @@ -266,6 +450,7 @@ 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);
> > #endif > > + auth_context.sig_size = 0; > > > > g = fopen(bin, "r"); > > if (!g) { > > @@ -281,11 +466,36 @@ 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 IS_ENABLED(CONFIG_EFI_CAPSULE_AUTHENTICATE) > > see above > > > + 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)) {