[PATCH v7 02/17] efi_loader: add signature verification functions
AKASHI Takahiro
takahiro.akashi at linaro.org
Tue Apr 14 04:51:39 CEST 2020
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.akashi at 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[];
+} __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 <patrick at 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>
+#include <linux/compat.h>
+#include <linux/oid_registry.h>
+#include <u-boot/rsa.h>
+#include <u-boot/sha256.h>
+/*
+ * avoid duplicated inclusion:
+ * #include "../lib/crypto/x509_parser.h"
+ */
+#include "../lib/crypto/pkcs7_parser.h"
+
+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 */
--
2.25.2
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