Heinrich,
On Tue, Apr 14, 2020 at 04:36:19PM +0200, Heinrich Schuchardt wrote:
> On 2020-04-14 04:51, AKASHI Takahiro wrote:
> > In this commit, implemented are a couple of helper functions which will be
> > used to materialize variable authentication as well as image authentication
> > in later patches.
> >
> > Signed-off-by: AKASHI Takahiro <takahiro.aka...@linaro.org>
> > ---
> > include/efi_api.h | 87 +++++
> > include/efi_loader.h | 72 ++++
> > lib/efi_loader/Makefile | 1 +
> > lib/efi_loader/efi_signature.c | 583 +++++++++++++++++++++++++++++++++
> > 4 files changed, 743 insertions(+)
> > create mode 100644 lib/efi_loader/efi_signature.c
> >
> > diff --git a/include/efi_api.h b/include/efi_api.h
> > index 1c40ffc4f56c..77d6bf2660b9 100644
> > --- a/include/efi_api.h
> > +++ b/include/efi_api.h
> > @@ -18,6 +18,7 @@
> >
> > #include <efi.h>
> > #include <charset.h>
> > +#include <pe.h>
> >
> > #ifdef CONFIG_EFI_LOADER
> > #include <asm/setjmp.h>
> > @@ -329,6 +330,10 @@ struct efi_runtime_services {
> > EFI_GUID(0x8be4df61, 0x93ca, 0x11d2, 0xaa, 0x0d, \
> > 0x00, 0xe0, 0x98, 0x03, 0x2b, 0x8c)
> >
> > +#define EFI_IMAGE_SECURITY_DATABASE_GUID \
> > + EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596, 0xa3, 0xbc, \
> > + 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f)
> > +
> > #define EFI_FDT_GUID \
> > EFI_GUID(0xb1b621d5, 0xf19c, 0x41a5, \
> > 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0)
> > @@ -1682,4 +1687,86 @@ struct efi_load_file_protocol {
> > #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MIN 0x00001000
> > #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MAX 0x00004000
> >
> > +/* Certificate types in signature database */
> > +#define EFI_CERT_SHA256_GUID \
> > + EFI_GUID(0xc1c41626, 0x504c, 0x4092, 0xac, 0xa9, \
> > + 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28)
> > +#define EFI_CERT_RSA2048_GUID \
> > + EFI_GUID(0x3c5766e8, 0x269c, 0x4e34, 0xaa, 0x14, \
> > + 0xed, 0x77, 0x6e, 0x85, 0xb3, 0xb6)
> > +#define EFI_CERT_X509_GUID \
> > + EFI_GUID(0xa5c059a1, 0x94e4, 0x4aa7, 0x87, 0xb5, \
> > + 0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72)
> > +#define EFI_CERT_X509_SHA256_GUID \
> > + EFI_GUID(0x3bd2a492, 0x96c0, 0x4079, 0xb4, 0x20, \
> > + 0xfc, 0xf9, 0x8e, 0xf1, 0x03, 0xed)
> > +#define EFI_CERT_TYPE_PKCS7_GUID \
> > + EFI_GUID(0x4aafd29d, 0x68df, 0x49ee, 0x8a, 0xa9, \
> > + 0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7)
> > +
> > +/**
> > + * win_certificate_uefi_guid - A certificate that encapsulates
> > + * a GUID-specific signature
> > + *
> > + * @hdr: Windows certificate header
> > + * @cert_type: Certificate type
> > + * @cert_data: Certificate data
> > + */
> > +struct win_certificate_uefi_guid {
> > + WIN_CERTIFICATE hdr;
> > + efi_guid_t cert_type;
> > + u8 cert_data[];
> > +} __attribute__((__packed__));
> > +
> > +/**
> > + * efi_variable_authentication_2 - A time-based authentication method
> > + * descriptor
> > + *
> > + * This structure describes an authentication information for
> > + * a variable with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
> > + * and should be included as part of a variable's value.
> > + * Only EFI_CERT_TYPE_PKCS7_GUID is accepted.
> > + *
> > + * @time_stamp: Descriptor's time stamp
> > + * @auth_info: Authentication info
> > + */
> > +struct efi_variable_authentication_2 {
> > + struct efi_time time_stamp;
> > + struct win_certificate_uefi_guid auth_info;
> > +} __attribute__((__packed__));
> > +
> > +/**
> > + * efi_signature_data - A format of signature
> > + *
> > + * This structure describes a single signature in signature database.
> > + *
> > + * @signature_owner: Signature owner
> > + * @signature_data: Signature data
> > + */
> > +struct efi_signature_data {
> > + efi_guid_t signature_owner;
> > + u8 signature_data[];
>
> Please, use [0].
Actually, there are a bunch of uses of [] notation in
efi.h, efi_api.h and efi_loader.h.
Do you really want to modify all?
> > +} __attribute__((__packed__));
> > +
> > +/**
> > + * efi_signature_list - A format of signature database
> > + *
> > + * This structure describes a list of signatures with the same type.
> > + * An authenticated variable's value is a concatenation of one or more
> > + * efi_signature_list's.
> > + *
> > + * @signature_type: Signature type
> > + * @signature_list_size: Size of signature list
> > + * @signature_header_size: Size of signature header
> > + * @signature_size: Size of signature
> > + */
> > +struct efi_signature_list {
> > + efi_guid_t signature_type;
> > + u32 signature_list_size;
> > + u32 signature_header_size;
> > + u32 signature_size;
> > +/* u8 signature_header[signature_header_size]; */
> > +/* struct efi_signature_data signatures[...][signature_size]; */
> > +} __attribute__((__packed__));
> > +
> > #endif
> > diff --git a/include/efi_loader.h b/include/efi_loader.h
> > index 3f2792892f34..8cf85d2fb7e2 100644
> > --- a/include/efi_loader.h
> > +++ b/include/efi_loader.h
> > @@ -26,6 +26,7 @@ static inline void *guidcpy(void *dst, const void *src)
> > #if CONFIG_IS_ENABLED(EFI_LOADER)
> >
> > #include <linux/list.h>
> > +#include <linux/oid_registry.h>
> >
> > /* Maximum number of configuration tables */
> > #define EFI_MAX_CONFIGURATION_TABLES 16
> > @@ -178,6 +179,11 @@ extern const efi_guid_t
> > efi_guid_hii_config_routing_protocol;
> > extern const efi_guid_t efi_guid_hii_config_access_protocol;
> > extern const efi_guid_t efi_guid_hii_database_protocol;
> > extern const efi_guid_t efi_guid_hii_string_protocol;
> > +/* GUIDs for authentication */
> > +extern const efi_guid_t efi_guid_image_security_database;
> > +extern const efi_guid_t efi_guid_sha256;
> > +extern const efi_guid_t efi_guid_cert_x509;
> > +extern const efi_guid_t efi_guid_cert_x509_sha256;
> >
> > /* GUID of RNG protocol */
> > extern const efi_guid_t efi_guid_rng_protocol;
> > @@ -680,6 +686,72 @@ void efi_deserialize_load_option(struct
> > efi_load_option *lo, u8 *data);
> > unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8
> > **data);
> > efi_status_t efi_bootmgr_load(efi_handle_t *handle);
> >
> > +#ifdef CONFIG_EFI_SECURE_BOOT
> > +#include <image.h>
> > +
> > +/**
> > + * efi_image_regions - A list of memory regions
> > + *
> > + * @max: Maximum number of regions
> > + * @num: Number of regions
> > + * @reg: array of regions
> > + */
> > +struct efi_image_regions {
> > + int max;
> > + int num;
> > + struct image_region reg[];
> > +};
> > +
> > +/**
> > + * efi_sig_data - A decoded data of struct efi_signature_data
> > + *
> > + * This structure represents an internal form of signature in
> > + * signature database. A listed list may represent a signature list.
> > + *
> > + * @next: Pointer to next entry
> > + * @onwer: Signature owner
> > + * @data: Pointer to signature data
> > + * @size: Size of signature data
> > + */
> > +struct efi_sig_data {
> > + struct efi_sig_data *next;
> > + efi_guid_t owner;
> > + void *data;
> > + size_t size;
> > +};
> > +
> > +/**
> > + * efi_signature_store - A decoded data of signature database
> > + *
> > + * This structure represents an internal form of signature database.
> > + *
> > + * @next: Pointer to next entry
> > + * @sig_type: Signature type
> > + * @sig_data_list: Pointer to signature list
> > + */
> > +struct efi_signature_store {
> > + struct efi_signature_store *next;
> > + efi_guid_t sig_type;
> > + struct efi_sig_data *sig_data_list;
> > +};
> > +
> > +struct x509_certificate;
> > +struct pkcs7_message;
> > +
> > +bool efi_signature_verify_cert(struct x509_certificate *cert,
> > + struct efi_signature_store *dbx);
> > +bool efi_signature_verify_signers(struct pkcs7_message *msg,
> > + struct efi_signature_store *dbx);
> > +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs,
> > + struct pkcs7_message *msg,
> > + struct efi_signature_store *db,
> > + struct x509_certificate **cert);
> > +
> > +efi_status_t efi_image_region_add(struct efi_image_regions *regs,
> > + const void *start, const void *end,
> > + int nocheck);
> > +#endif /* CONFIG_EFI_SECURE_BOOT */
> > +
> > #else /* CONFIG_IS_ENABLED(EFI_LOADER) */
> >
> > /* Without CONFIG_EFI_LOADER we don't have a runtime section, stub it out
> > */
> > diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
> > index 9b3b70447336..eff3c25ec301 100644
> > --- a/lib/efi_loader/Makefile
> > +++ b/lib/efi_loader/Makefile
> > @@ -44,3 +44,4 @@ obj-$(CONFIG_GENERATE_ACPI_TABLE) += efi_acpi.o
> > obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += efi_smbios.o
> > obj-$(CONFIG_EFI_RNG_PROTOCOL) += efi_rng.o
> > obj-$(CONFIG_EFI_LOAD_FILE2_INITRD) += efi_load_initrd.o
> > +obj-y += efi_signature.o
> > diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c
> > new file mode 100644
> > index 000000000000..23dac94c0593
> > --- /dev/null
> > +++ b/lib/efi_loader/efi_signature.c
> > @@ -0,0 +1,583 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (c) 2018 Patrick Wildt <patr...@blueri.se>
> > + * Copyright (c) 2019 Linaro Limited, Author: AKASHI Takahiro
> > + */
> > +
> > +#include <common.h>
> > +#include <charset.h>
> > +#include <efi_loader.h>
> > +#include <image.h>
> > +#include <hexdump.h>
> > +#include <malloc.h>
> > +#include <pe.h>
>
> You just added pe.h to efi_api.h which is included in efi_loader.h.
> Please, avoid adding the includes twice.
I agree as there is no use of any symbols from pe.h here.
> > +#include <linux/compat.h>
> > +#include <linux/oid_registry.h>
> > +#include <u-boot/rsa.h>
> > +#include <u-boot/sha256.h>
> > +/*
> > + * avoid duplicated inclusion:
>
> Why don't you fix the lib/crypto/x509_parser.h that you created? Just
> add the missing
>
> #ifdef _X509_PARSER_H
> #define _X509_PARSER_H
> #endif /* _X509_PARSER_H */
Okay.
> Same problem in pkcs7_parser.h.
>
> > + * #include "../lib/crypto/x509_parser.h"
> > + */
>
> If you patch is working I see no reason to add the comment here.
>
> > +#include "../lib/crypto/pkcs7_parser.h"
>
> Why is pkcs7_parser.h in lib/ and not in include/?
>
> I would prefer to avoid relative paths.
My basic approach was to minimize the modification to the original
(i.e. linux code) as much as possible.
Anyhow, I will try to fix it.
Thanks,
-Takahiro Akashi
> I will remove the superfluous comment and include when merging. The rest
> can be fixed later.
>
> Best regards
>
> Heinrich
>
> > +
> > +const efi_guid_t efi_guid_image_security_database =
> > + EFI_IMAGE_SECURITY_DATABASE_GUID;
> > +const efi_guid_t efi_guid_sha256 = EFI_CERT_SHA256_GUID;
> > +const efi_guid_t efi_guid_cert_rsa2048 = EFI_CERT_RSA2048_GUID;
> > +const efi_guid_t efi_guid_cert_x509 = EFI_CERT_X509_GUID;
> > +const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID;
> > +
> > +#ifdef CONFIG_EFI_SECURE_BOOT
> > +
> > +/**
> > + * efi_hash_regions - calculate a hash value
> > + * @regs: List of regions
> > + * @hash: Pointer to a pointer to buffer holding a hash value
> > + * @size: Size of buffer to be returned
> > + *
> > + * Calculate a sha256 value of @regs and return a value in @hash.
> > + *
> > + * Return: true on success, false on error
> > + */
> > +static bool efi_hash_regions(struct efi_image_regions *regs, void **hash,
> > + size_t *size)
> > +{
> > + *size = 0;
> > + *hash = calloc(1, SHA256_SUM_LEN);
> > + if (!*hash) {
> > + debug("Out of memory\n");
> > + return false;
> > + }
> > + *size = SHA256_SUM_LEN;
> > +
> > + hash_calculate("sha256", regs->reg, regs->num, *hash);
> > +#ifdef DEBUG
> > + debug("hash calculated:\n");
> > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1,
> > + *hash, SHA256_SUM_LEN, false);
> > +#endif
> > +
> > + return true;
> > +}
> > +
> > +/**
> > + * efi_hash_msg_content - calculate a hash value of contentInfo
> > + * @msg: Signature
> > + * @hash: Pointer to a pointer to buffer holding a hash value
> > + * @size: Size of buffer to be returned
> > + *
> > + * Calculate a sha256 value of contentInfo in @msg and return a value in
> > @hash.
> > + *
> > + * Return: true on success, false on error
> > + */
> > +static bool efi_hash_msg_content(struct pkcs7_message *msg, void **hash,
> > + size_t *size)
> > +{
> > + struct image_region regtmp;
> > +
> > + *size = 0;
> > + *hash = calloc(1, SHA256_SUM_LEN);
> > + if (!*hash) {
> > + debug("Out of memory\n");
> > + free(msg);
> > + return false;
> > + }
> > + *size = SHA256_SUM_LEN;
> > +
> > + regtmp.data = msg->data;
> > + regtmp.size = msg->data_len;
> > +
> > + hash_calculate("sha256", ®tmp, 1, *hash);
> > +#ifdef DEBUG
> > + debug("hash calculated based on contentInfo:\n");
> > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1,
> > + *hash, SHA256_SUM_LEN, false);
> > +#endif
> > +
> > + return true;
> > +}
> > +
> > +/**
> > + * efi_signature_verify - verify a signature with a certificate
> > + * @regs: List of regions to be authenticated
> > + * @signed_info: Pointer to PKCS7's signed_info
> > + * @cert: x509 certificate
> > + *
> > + * Signature pointed to by @signed_info against image pointed to by @regs
> > + * is verified by a certificate pointed to by @cert.
> > + * @signed_info holds a signature, including a message digest which is to
> > be
> > + * compared with a hash value calculated from @regs.
> > + *
> > + * Return: true if signature is verified, false if not
> > + */
> > +static bool efi_signature_verify(struct efi_image_regions *regs,
> > + struct pkcs7_message *msg,
> > + struct pkcs7_signed_info *ps_info,
> > + struct x509_certificate *cert)
> > +{
> > + struct image_sign_info info;
> > + struct image_region regtmp[2];
> > + void *hash;
> > + size_t size;
> > + char c;
> > + bool verified;
> > +
> > + debug("%s: Enter, %p, %p, %p(issuer: %s, subject: %s)\n", __func__,
> > + regs, ps_info, cert, cert->issuer, cert->subject);
> > +
> > + verified = false;
> > +
> > + memset(&info, '\0', sizeof(info));
> > + info.padding = image_get_padding_algo("pkcs-1.5");
> > + /*
> > + * Note: image_get_[checksum|crypto]_algo takes an string
> > + * argument like "<checksum>,<crypto>"
> > + * TODO: support other hash algorithms
> > + */
> > + if (!strcmp(ps_info->sig->hash_algo, "sha1")) {
> > + info.checksum = image_get_checksum_algo("sha1,rsa2048");
> > + info.name = "sha1,rsa2048";
> > + } else if (!strcmp(ps_info->sig->hash_algo, "sha256")) {
> > + info.checksum = image_get_checksum_algo("sha256,rsa2048");
> > + info.name = "sha256,rsa2048";
> > + } else {
> > + debug("unknown msg digest algo: %s\n", ps_info->sig->hash_algo);
> > + goto out;
> > + }
> > + info.crypto = image_get_crypto_algo(info.name);
> > +
> > + info.key = cert->pub->key;
> > + info.keylen = cert->pub->keylen;
> > +
> > + /* verify signature */
> > + debug("%s: crypto: %s, signature len:%x\n", __func__,
> > + info.name, ps_info->sig->s_size);
> > + if (ps_info->aa_set & (1UL << sinfo_has_message_digest)) {
> > + debug("%s: RSA verify authentication attribute\n", __func__);
> > + /*
> > + * NOTE: This path will be executed only for
> > + * PE image authentication
> > + */
> > +
> > + /* check if hash matches digest first */
> > + debug("checking msg digest first, len:0x%x\n",
> > + ps_info->msgdigest_len);
> > +
> > +#ifdef DEBUG
> > + debug("hash in database:\n");
> > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1,
> > + ps_info->msgdigest, ps_info->msgdigest_len,
> > + false);
> > +#endif
> > + /* against contentInfo first */
> > + if ((msg->data && efi_hash_msg_content(msg, &hash, &size)) ||
> > + /* for signed image */
> > + efi_hash_regions(regs, &hash, &size)) {
> > + /* for authenticated variable */
> > + if (ps_info->msgdigest_len != size ||
> > + memcmp(hash, ps_info->msgdigest, size)) {
> > + debug("Digest doesn't match\n");
> > + free(hash);
> > + goto out;
> > + }
> > +
> > + free(hash);
> > + } else {
> > + debug("Digesting image failed\n");
> > + goto out;
> > + }
> > +
> > + /* against digest */
> > + c = 0x31;
> > + regtmp[0].data = &c;
> > + regtmp[0].size = 1;
> > + regtmp[1].data = ps_info->authattrs;
> > + regtmp[1].size = ps_info->authattrs_len;
> > +
> > + if (!rsa_verify(&info, regtmp, 2,
> > + ps_info->sig->s, ps_info->sig->s_size))
> > + verified = true;
> > + } else {
> > + debug("%s: RSA verify content data\n", __func__);
> > + /* against all data */
> > + if (!rsa_verify(&info, regs->reg, regs->num,
> > + ps_info->sig->s, ps_info->sig->s_size))
> > + verified = true;
> > + }
> > +
> > +out:
> > + debug("%s: Exit, verified: %d\n", __func__, verified);
> > + return verified;
> > +}
> > +
> > +/**
> > + * efi_signature_verify_with_list - verify a signature with signature list
> > + * @regs: List of regions to be authenticated
> > + * @msg: Signature
> > + * @signed_info: Pointer to PKCS7's signed_info
> > + * @siglist: Signature list for certificates
> > + * @valid_cert: x509 certificate that verifies this signature
> > + *
> > + * Signature pointed to by @signed_info against image pointed to by @regs
> > + * is verified by signature list pointed to by @siglist.
> > + * Signature database is a simple concatenation of one or more
> > + * signature list(s).
> > + *
> > + * Return: true if signature is verified, false if not
> > + */
> > +static
> > +bool efi_signature_verify_with_list(struct efi_image_regions *regs,
> > + struct pkcs7_message *msg,
> > + struct pkcs7_signed_info *signed_info,
> > + struct efi_signature_store *siglist,
> > + struct x509_certificate **valid_cert)
> > +{
> > + struct x509_certificate *cert;
> > + struct efi_sig_data *sig_data;
> > + bool verified = false;
> > +
> > + debug("%s: Enter, %p, %p, %p, %p\n", __func__,
> > + regs, signed_info, siglist, valid_cert);
> > +
> > + if (!signed_info) {
> > + void *hash;
> > + size_t size;
> > +
> > + debug("%s: unsigned image\n", __func__);
> > + /*
> > + * verify based on calculated hash value
> > + * TODO: support other hash algorithms
> > + */
> > + if (guidcmp(&siglist->sig_type, &efi_guid_sha256)) {
> > + debug("Digest algorithm is not supported: %pUl\n",
> > + &siglist->sig_type);
> > + goto out;
> > + }
> > +
> > + if (!efi_hash_regions(regs, &hash, &size)) {
> > + debug("Digesting unsigned image failed\n");
> > + goto out;
> > + }
> > +
> > + /* go through the list */
> > + for (sig_data = siglist->sig_data_list; sig_data;
> > + sig_data = sig_data->next) {
> > +#ifdef DEBUG
> > + debug("Msg digest in database:\n");
> > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1,
> > + sig_data->data, sig_data->size, false);
> > +#endif
> > + if ((sig_data->size == size) &&
> > + !memcmp(sig_data->data, hash, size)) {
> > + verified = true;
> > + free(hash);
> > + goto out;
> > + }
> > + }
> > + free(hash);
> > + goto out;
> > + }
> > +
> > + debug("%s: signed image\n", __func__);
> > + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) {
> > + debug("Signature type is not supported: %pUl\n",
> > + &siglist->sig_type);
> > + goto out;
> > + }
> > +
> > + /* go through the list */
> > + for (sig_data = siglist->sig_data_list; sig_data;
> > + sig_data = sig_data->next) {
> > + /* TODO: support owner check based on policy */
> > +
> > + cert = x509_cert_parse(sig_data->data, sig_data->size);
> > + if (IS_ERR(cert)) {
> > + debug("Parsing x509 certificate failed\n");
> > + goto out;
> > + }
> > +
> > + verified = efi_signature_verify(regs, msg, signed_info, cert);
> > +
> > + if (verified) {
> > + if (valid_cert)
> > + *valid_cert = cert;
> > + else
> > + x509_free_certificate(cert);
> > + break;
> > + }
> > + x509_free_certificate(cert);
> > + }
> > +
> > +out:
> > + debug("%s: Exit, verified: %d\n", __func__, verified);
> > + return verified;
> > +}
> > +
> > +/**
> > + * efi_signature_verify_with_sigdb - verify a signature with db
> > + * @regs: List of regions to be authenticated
> > + * @msg: Signature
> > + * @db: Signature database for trusted certificates
> > + * @cert: x509 certificate that verifies this signature
> > + *
> > + * Signature pointed to by @msg against image pointed to by @regs
> > + * is verified by signature database pointed to by @db.
> > + *
> > + * Return: true if signature is verified, false if not
> > + */
> > +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs,
> > + struct pkcs7_message *msg,
> > + struct efi_signature_store *db,
> > + struct x509_certificate **cert)
> > +{
> > + struct pkcs7_signed_info *info;
> > + struct efi_signature_store *siglist;
> > + bool verified = false;
> > +
> > + debug("%s: Enter, %p, %p, %p, %p\n", __func__, regs, msg, db, cert);
> > +
> > + if (!db)
> > + goto out;
> > +
> > + if (!db->sig_data_list)
> > + goto out;
> > +
> > + /* for unsigned image */
> > + if (!msg) {
> > + debug("%s: Verify unsigned image with db\n", __func__);
> > + for (siglist = db; siglist; siglist = siglist->next)
> > + if (efi_signature_verify_with_list(regs, NULL, NULL,
> > + siglist, cert)) {
> > + verified = true;
> > + goto out;
> > + }
> > +
> > + goto out;
> > + }
> > +
> > + /* for signed image or variable */
> > + debug("%s: Verify signed image with db\n", __func__);
> > + for (info = msg->signed_infos; info; info = info->next) {
> > + debug("Signed Info: digest algo: %s, pkey algo: %s\n",
> > + info->sig->hash_algo, info->sig->pkey_algo);
> > +
> > + for (siglist = db; siglist; siglist = siglist->next) {
> > + if (efi_signature_verify_with_list(regs, msg, info,
> > + siglist, cert)) {
> > + verified = true;
> > + goto out;
> > + }
> > + }
> > + }
> > +
> > +out:
> > + debug("%s: Exit, verified: %d\n", __func__, verified);
> > + return verified;
> > +}
> > +
> > +/**
> > + * efi_search_siglist - search signature list for a certificate
> > + * @cert: x509 certificate
> > + * @siglist: Signature list
> > + * @revoc_time: Pointer to buffer for revocation time
> > + *
> > + * Search signature list pointed to by @siglist and find a certificate
> > + * pointed to by @cert.
> > + * If found, revocation time that is specified in signature database is
> > + * returned in @revoc_time.
> > + *
> > + * Return: true if certificate is found, false if not
> > + */
> > +static bool efi_search_siglist(struct x509_certificate *cert,
> > + struct efi_signature_store *siglist,
> > + time64_t *revoc_time)
> > +{
> > + struct image_region reg[1];
> > + void *hash = NULL, *msg = NULL;
> > + struct efi_sig_data *sig_data;
> > + bool found = false;
> > +
> > + /* can be null */
> > + if (!siglist->sig_data_list)
> > + return false;
> > +
> > + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509_sha256)) {
> > + /* TODO: other hash algos */
> > + debug("Certificate's digest type is not supported: %pUl\n",
> > + &siglist->sig_type);
> > + goto out;
> > + }
> > +
> > + /* calculate hash of TBSCertificate */
> > + msg = calloc(1, SHA256_SUM_LEN);
> > + if (!msg) {
> > + debug("Out of memory\n");
> > + goto out;
> > + }
> > +
> > + hash = calloc(1, SHA256_SUM_LEN);
> > + if (!hash) {
> > + debug("Out of memory\n");
> > + goto out;
> > + }
> > +
> > + reg[0].data = cert->tbs;
> > + reg[0].size = cert->tbs_size;
> > + hash_calculate("sha256", reg, 1, msg);
> > +
> > + /* go through signature list */
> > + for (sig_data = siglist->sig_data_list; sig_data;
> > + sig_data = sig_data->next) {
> > + /*
> > + * struct efi_cert_x509_sha256 {
> > + * u8 tbs_hash[256/8];
> > + * time64_t revocation_time;
> > + * };
> > + */
> > + if ((sig_data->size == SHA256_SUM_LEN) &&
> > + !memcmp(sig_data->data, hash, SHA256_SUM_LEN)) {
> > + memcpy(revoc_time, sig_data->data + SHA256_SUM_LEN,
> > + sizeof(*revoc_time));
> > + found = true;
> > + goto out;
> > + }
> > + }
> > +
> > +out:
> > + free(hash);
> > + free(msg);
> > +
> > + return found;
> > +}
> > +
> > +/**
> > + * efi_signature_verify_cert - verify a certificate with dbx
> > + * @cert: x509 certificate
> > + * @dbx: Signature database
> > + *
> > + * Search signature database pointed to by @dbx and find a certificate
> > + * pointed to by @cert.
> > + * This function is expected to be used against "dbx".
> > + *
> > + * Return: true if a certificate is not rejected, false otherwise.
> > + */
> > +bool efi_signature_verify_cert(struct x509_certificate *cert,
> > + struct efi_signature_store *dbx)
> > +{
> > + struct efi_signature_store *siglist;
> > + time64_t revoc_time;
> > + bool found = false;
> > +
> > + debug("%s: Enter, %p, %p\n", __func__, dbx, cert);
> > +
> > + if (!cert)
> > + return false;
> > +
> > + for (siglist = dbx; siglist; siglist = siglist->next) {
> > + if (efi_search_siglist(cert, siglist, &revoc_time)) {
> > + /* TODO */
> > + /* compare signing time with revocation time */
> > +
> > + found = true;
> > + break;
> > + }
> > + }
> > +
> > + debug("%s: Exit, verified: %d\n", __func__, !found);
> > + return !found;
> > +}
> > +
> > +/**
> > + * efi_signature_verify_signers - verify signers' certificates with dbx
> > + * @msg: Signature
> > + * @dbx: Signature database
> > + *
> > + * Determine if any of signers' certificates in @msg may be verified
> > + * by any of certificates in signature database pointed to by @dbx.
> > + * This function is expected to be used against "dbx".
> > + *
> > + * Return: true if none of certificates is rejected, false otherwise.
> > + */
> > +bool efi_signature_verify_signers(struct pkcs7_message *msg,
> > + struct efi_signature_store *dbx)
> > +{
> > + struct pkcs7_signed_info *info;
> > + bool found = false;
> > +
> > + debug("%s: Enter, %p, %p\n", __func__, msg, dbx);
> > +
> > + if (!msg)
> > + goto out;
> > +
> > + for (info = msg->signed_infos; info; info = info->next) {
> > + if (info->signer &&
> > + !efi_signature_verify_cert(info->signer, dbx)) {
> > + found = true;
> > + goto out;
> > + }
> > + }
> > +out:
> > + debug("%s: Exit, verified: %d\n", __func__, !found);
> > + return !found;
> > +}
> > +
> > +/**
> > + * efi_image_region_add - add an entry of region
> > + * @regs: Pointer to array of regions
> > + * @start: Start address of region
> > + * @end: End address of region
> > + * @nocheck: flag against overlapped regions
> > + *
> > + * Take one entry of region [@start, @end] and append it to the list
> > + * pointed to by @regs. If @nocheck is false, overlapping among entries
> > + * will be checked first.
> > + *
> > + * Return: 0 on success, status code (negative) on error
> > + */
> > +efi_status_t efi_image_region_add(struct efi_image_regions *regs,
> > + const void *start, const void *end,
> > + int nocheck)
> > +{
> > + struct image_region *reg;
> > + int i, j;
> > +
> > + if (regs->num >= regs->max) {
> > + debug("%s: no more room for regions\n", __func__);
> > + return EFI_OUT_OF_RESOURCES;
> > + }
> > +
> > + if (end < start)
> > + return EFI_INVALID_PARAMETER;
> > +
> > + for (i = 0; i < regs->num; i++) {
> > + reg = ®s->reg[i];
> > + if (nocheck)
> > + continue;
> > +
> > + if (start > reg->data + reg->size)
> > + continue;
> > +
> > + if ((start >= reg->data && start < reg->data + reg->size) ||
> > + (end > reg->data && end < reg->data + reg->size)) {
> > + debug("%s: new region already part of another\n",
> > + __func__);
> > + return EFI_INVALID_PARAMETER;
> > + }
> > +
> > + if (start < reg->data && end < reg->data + reg->size) {
> > + for (j = regs->num - 1; j >= i; j--)
> > + memcpy(®s->reg[j], ®s->reg[j + 1],
> > + sizeof(*reg));
> > + break;
> > + }
> > + }
> > +
> > + reg = ®s->reg[i];
> > + reg->data = start;
> > + reg->size = end - start;
> > + regs->num++;
> > +
> > + return EFI_SUCCESS;
> > +}
> > +#endif /* CONFIG_EFI_SECURE_BOOT */
> >
>
