lib/efi_loader/efi_signature.c - platform/external/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (c) 2018 Patrick Wildt <patrick@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 <crypto/pkcs7_parser.h>
 #include <linux/compat.h>
 #include <linux/oid_registry.h>
 #include <u-boot/rsa.h>
 #include <u-boot/sha256.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;
 const efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_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) {
 		EFI_PRINT("Out of memory\n");
 		return false;
 	}
 	*size = SHA256_SUM_LEN;

 	hash_calculate("sha256", regs->reg, regs->num, *hash);
 #ifdef DEBUG
 	EFI_PRINT("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) {
 		EFI_PRINT("Out of memory\n");
 		free(msg);
 		return false;
 	}
 	*size = SHA256_SUM_LEN;

 	regtmp.data = msg->data;
 	regtmp.size = msg->data_len;

 	hash_calculate("sha256", &regtmp, 1, *hash);
 #ifdef DEBUG
 	EFI_PRINT("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;

 	EFI_PRINT("%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 {
 		EFI_PRINT("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 */
 	EFI_PRINT("%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)) {
 		EFI_PRINT("%s: RSA verify authentication attribute\n",
 			  __func__);
 		/*
 		 * NOTE: This path will be executed only for
 		 * PE image authentication
 		 */

 		/* check if hash matches digest first */
 		EFI_PRINT("checking msg digest first, len:0x%x\n",
 			  ps_info->msgdigest_len);

 #ifdef DEBUG
 		EFI_PRINT("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)) {
 				EFI_PRINT("Digest doesn't match\n");
 				free(hash);
 				goto out;
 			}

 			free(hash);
 		} else {
 			EFI_PRINT("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 {
 		EFI_PRINT("%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:
 	EFI_PRINT("%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;

 	EFI_PRINT("%s: Enter, %p, %p, %p, %p\n", __func__,
 		  regs, signed_info, siglist, valid_cert);

 	if (!signed_info) {
 		void *hash;
 		size_t size;

 		EFI_PRINT("%s: unsigned image\n", __func__);
 		/*
 		 * verify based on calculated hash value
 		 * TODO: support other hash algorithms
 		 */
 		if (guidcmp(&siglist->sig_type, &efi_guid_sha256)) {
 			EFI_PRINT("Digest algorithm is not supported: %pUl\n",
 				  &siglist->sig_type);
 			goto out;
 		}

 		if (!efi_hash_regions(regs, &hash, &size)) {
 			EFI_PRINT("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
 			EFI_PRINT("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;
 	}

 	EFI_PRINT("%s: signed image\n", __func__);
 	if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) {
 		EFI_PRINT("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)) {
 			EFI_PRINT("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:
 	EFI_PRINT("%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;

 	EFI_PRINT("%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) {
 		EFI_PRINT("%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 */
 	EFI_PRINT("%s: Verify signed image with db\n", __func__);
 	for (info = msg->signed_infos; info; info = info->next) {
 		EFI_PRINT("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:
 	EFI_PRINT("%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 */
 		EFI_PRINT("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) {
 		EFI_PRINT("Out of memory\n");
 		goto out;
 	}

 	hash = calloc(1, SHA256_SUM_LEN);
 	if (!hash) {
 		EFI_PRINT("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;

 	EFI_PRINT("%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;
 		}
 	}

 	EFI_PRINT("%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;

 	EFI_PRINT("%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:
 	EFI_PRINT("%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 (included)
  * @end:	End address of region (excluded)
  * @nocheck:	flag against overlapped regions
  *
  * Take one entry of region [@start, @end[ and insert it into the list.
  *
  * * If @nocheck is false, the list will be sorted ascending by address.
  *   Overlapping entries will not be allowed.
  *
  * * If @nocheck is true, the list will be sorted ascending by sequence
  *   of adding the entries. Overlapping is allowed.
  *
  * Return:	status code
  */
 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) {
 		EFI_PRINT("%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 = &regs->reg[i];
 		if (nocheck)
 			continue;

 		/* new data after registered region */
 		if (start >= reg->data + reg->size)
 			continue;

 		/* new data preceding registered region */
 		if (end <= reg->data) {
 			for (j = regs->num - 1; j >= i; j--)
 				memcpy(&regs->reg[j + 1], &regs->reg[j],
 				       sizeof(*reg));
 			break;
 		}

 		/* new data overlapping registered region */
 		EFI_PRINT("%s: new region already part of another\n", __func__);
 		return EFI_INVALID_PARAMETER;
 	}

 	reg = &regs->reg[i];
 	reg->data = start;
 	reg->size = end - start;
 	regs->num++;

 	return EFI_SUCCESS;
 }

 /**
  * efi_sigstore_free - free signature store
  * @sigstore:	Pointer to signature store structure
  *
  * Feee all the memories held in signature store and itself,
  * which were allocated by efi_sigstore_parse_sigdb().
  */
 void efi_sigstore_free(struct efi_signature_store *sigstore)
 {
 	struct efi_signature_store *sigstore_next;
 	struct efi_sig_data *sig_data, *sig_data_next;

 	while (sigstore) {
 		sigstore_next = sigstore->next;

 		sig_data = sigstore->sig_data_list;
 		while (sig_data) {
 			sig_data_next = sig_data->next;
 			free(sig_data->data);
 			free(sig_data);
 			sig_data = sig_data_next;
 		}

 		free(sigstore);
 		sigstore = sigstore_next;
 	}
 }

 /**
  * efi_sigstore_parse_siglist - parse a signature list
  * @name:	Pointer to signature list
  *
  * Parse signature list and instantiate a signature store structure.
  * Signature database is a simple concatenation of one or more
  * signature list(s).
  *
  * Return:	Pointer to signature store on success, NULL on error
  */
 static struct efi_signature_store *
 efi_sigstore_parse_siglist(struct efi_signature_list *esl)
 {
 	struct efi_signature_store *siglist = NULL;
 	struct efi_sig_data *sig_data, *sig_data_next;
 	struct efi_signature_data *esd;
 	size_t left;

 	/*
 	 * UEFI specification defines certificate types:
 	 *   for non-signed images,
 	 *	EFI_CERT_SHA256_GUID
 	 *	EFI_CERT_RSA2048_GUID
 	 *	EFI_CERT_RSA2048_SHA256_GUID
 	 *	EFI_CERT_SHA1_GUID
 	 *	EFI_CERT_RSA2048_SHA_GUID
 	 *	EFI_CERT_SHA224_GUID
 	 *	EFI_CERT_SHA384_GUID
 	 *	EFI_CERT_SHA512_GUID
 	 *
 	 *   for signed images,
 	 *	EFI_CERT_X509_GUID
 	 *	NOTE: Each certificate will normally be in a separate
 	 *	EFI_SIGNATURE_LIST as the size may vary depending on
 	 *	its algo's.
 	 *
 	 *   for timestamp revocation of certificate,
 	 *	EFI_CERT_X509_SHA512_GUID
 	 *	EFI_CERT_X509_SHA256_GUID
 	 *	EFI_CERT_X509_SHA384_GUID
 	 */

 	if (esl->signature_list_size
 			<= (sizeof(*esl) + esl->signature_header_size)) {
 		EFI_PRINT("Siglist in wrong format\n");
 		return NULL;
 	}

 	/* Create a head */
 	siglist = calloc(sizeof(*siglist), 1);
 	if (!siglist) {
 		EFI_PRINT("Out of memory\n");
 		goto err;
 	}
 	memcpy(&siglist->sig_type, &esl->signature_type, sizeof(efi_guid_t));

 	/* Go through the list */
 	sig_data_next = NULL;
 	left = esl->signature_list_size
 			- (sizeof(*esl) + esl->signature_header_size);
 	esd = (struct efi_signature_data *)
 			((u8 *)esl + sizeof(*esl) + esl->signature_header_size);

 	while (left > 0) {
 		/* Signature must exist if there is remaining data. */
 		if (left < esl->signature_size) {
 			EFI_PRINT("Certificate is too small\n");
 			goto err;
 		}

 		sig_data = calloc(esl->signature_size
 					- sizeof(esd->signature_owner), 1);
 		if (!sig_data) {
 			EFI_PRINT("Out of memory\n");
 			goto err;
 		}

 		/* Append signature data */
 		memcpy(&sig_data->owner, &esd->signature_owner,
 		       sizeof(efi_guid_t));
 		sig_data->size = esl->signature_size
 					- sizeof(esd->signature_owner);
 		sig_data->data = malloc(sig_data->size);
 		if (!sig_data->data) {
 			EFI_PRINT("Out of memory\n");
 			goto err;
 		}
 		memcpy(sig_data->data, esd->signature_data, sig_data->size);

 		sig_data->next = sig_data_next;
 		sig_data_next = sig_data;

 		/* Next */
 		esd = (struct efi_signature_data *)
 				((u8 *)esd + esl->signature_size);
 		left -= esl->signature_size;
 	}
 	siglist->sig_data_list = sig_data_next;

 	return siglist;

 err:
 	efi_sigstore_free(siglist);

 	return NULL;
 }

 /**
  * efi_sigstore_parse_sigdb - parse a signature database variable
  * @name:	Variable's name
  *
  * Read in a value of signature database variable pointed to by
  * @name, parse it and instantiate a signature store structure.
  *
  * Return:	Pointer to signature store on success, NULL on error
  */
 struct efi_signature_store *efi_sigstore_parse_sigdb(u16 *name)
 {
 	struct efi_signature_store *sigstore = NULL, *siglist;
 	struct efi_signature_list *esl;
 	const efi_guid_t *vendor;
 	void *db;
 	efi_uintn_t db_size;
 	efi_status_t ret;

 	if (!u16_strcmp(name, L"PK") || !u16_strcmp(name, L"KEK")) {
 		vendor = &efi_global_variable_guid;
 	} else if (!u16_strcmp(name, L"db") || !u16_strcmp(name, L"dbx")) {
 		vendor = &efi_guid_image_security_database;
 	} else {
 		EFI_PRINT("unknown signature database, %ls\n", name);
 		return NULL;
 	}

 	/* retrieve variable data */
 	db_size = 0;
 	ret = EFI_CALL(efi_get_variable(name, vendor, NULL, &db_size, NULL));
 	if (ret == EFI_NOT_FOUND) {
 		EFI_PRINT("variable, %ls, not found\n", name);
 		sigstore = calloc(sizeof(*sigstore), 1);
 		return sigstore;
 	} else if (ret != EFI_BUFFER_TOO_SMALL) {
 		EFI_PRINT("Getting variable, %ls, failed\n", name);
 		return NULL;
 	}

 	db = malloc(db_size);
 	if (!db) {
 		EFI_PRINT("Out of memory\n");
 		return NULL;
 	}

 	ret = EFI_CALL(efi_get_variable(name, vendor, NULL, &db_size, db));
 	if (ret != EFI_SUCCESS) {
 		EFI_PRINT("Getting variable, %ls, failed\n", name);
 		goto err;
 	}

 	/* Parse siglist list */
 	esl = db;
 	while (db_size > 0) {
 		/* List must exist if there is remaining data. */
 		if (db_size < sizeof(*esl)) {
 			EFI_PRINT("variable, %ls, in wrong format\n", name);
 			goto err;
 		}

 		if (db_size < esl->signature_list_size) {
 			EFI_PRINT("variable, %ls, in wrong format\n", name);
 			goto err;
 		}

 		/* Parse a single siglist. */
 		siglist = efi_sigstore_parse_siglist(esl);
 		if (!siglist) {
 			EFI_PRINT("Parsing signature list of %ls failed\n",
 				  name);
 			goto err;
 		}

 		/* Append siglist */
 		siglist->next = sigstore;
 		sigstore = siglist;

 		/* Next */
 		db_size -= esl->signature_list_size;
 		esl = (void *)esl + esl->signature_list_size;
 	}
 	free(db);

 	return sigstore;

 err:
 	efi_sigstore_free(sigstore);
 	free(db);

 	return NULL;
 }
 #endif /* CONFIG_EFI_SECURE_BOOT */
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright (c) 2018 Patrick Wildt <patrick@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 <crypto/pkcs7_parser.h>
	#include <linux/compat.h>
	#include <linux/oid_registry.h>
	#include <u-boot/rsa.h>
	#include <u-boot/sha256.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;
	const efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_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) {
	EFI_PRINT("Out of memory\n");
	return false;
	}
	*size = SHA256_SUM_LEN;

	hash_calculate("sha256", regs->reg, regs->num, *hash);
	#ifdef DEBUG
	EFI_PRINT("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) {
	EFI_PRINT("Out of memory\n");
	free(msg);
	return false;
	}
	*size = SHA256_SUM_LEN;

	regtmp.data = msg->data;
	regtmp.size = msg->data_len;

	hash_calculate("sha256", &regtmp, 1, *hash);
	#ifdef DEBUG
	EFI_PRINT("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;

	EFI_PRINT("%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 {
	EFI_PRINT("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 */
	EFI_PRINT("%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)) {
	EFI_PRINT("%s: RSA verify authentication attribute\n",
	__func__);
	/*
	* NOTE: This path will be executed only for
	* PE image authentication
	*/

	/* check if hash matches digest first */
	EFI_PRINT("checking msg digest first, len:0x%x\n",
	ps_info->msgdigest_len);

	#ifdef DEBUG
	EFI_PRINT("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)) {
	EFI_PRINT("Digest doesn't match\n");
	free(hash);
	goto out;
	}

	free(hash);
	} else {
	EFI_PRINT("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 {
	EFI_PRINT("%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:
	EFI_PRINT("%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;

	EFI_PRINT("%s: Enter, %p, %p, %p, %p\n", __func__,
	regs, signed_info, siglist, valid_cert);

	if (!signed_info) {
	void *hash;
	size_t size;

	EFI_PRINT("%s: unsigned image\n", __func__);
	/*
	* verify based on calculated hash value
	* TODO: support other hash algorithms
	*/
	if (guidcmp(&siglist->sig_type, &efi_guid_sha256)) {
	EFI_PRINT("Digest algorithm is not supported: %pUl\n",
	&siglist->sig_type);
	goto out;
	}

	if (!efi_hash_regions(regs, &hash, &size)) {
	EFI_PRINT("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
	EFI_PRINT("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;
	}

	EFI_PRINT("%s: signed image\n", __func__);
	if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) {
	EFI_PRINT("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)) {
	EFI_PRINT("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:
	EFI_PRINT("%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;

	EFI_PRINT("%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) {
	EFI_PRINT("%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 */
	EFI_PRINT("%s: Verify signed image with db\n", __func__);
	for (info = msg->signed_infos; info; info = info->next) {
	EFI_PRINT("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:
	EFI_PRINT("%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 */
	EFI_PRINT("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) {
	EFI_PRINT("Out of memory\n");
	goto out;
	}

	hash = calloc(1, SHA256_SUM_LEN);
	if (!hash) {
	EFI_PRINT("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;

	EFI_PRINT("%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;
	}
	}

	EFI_PRINT("%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;

	EFI_PRINT("%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:
	EFI_PRINT("%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 (included)
	* @end: End address of region (excluded)
	* @nocheck: flag against overlapped regions
	*
	* Take one entry of region [@start, @end[ and insert it into the list.
	*
	* * If @nocheck is false, the list will be sorted ascending by address.
	* Overlapping entries will not be allowed.
	*
	* * If @nocheck is true, the list will be sorted ascending by sequence
	* of adding the entries. Overlapping is allowed.
	*
	* Return: status code
	*/
	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) {
	EFI_PRINT("%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 = &regs->reg[i];
	if (nocheck)
	continue;

	/* new data after registered region */
	if (start >= reg->data + reg->size)
	continue;

	/* new data preceding registered region */
	if (end <= reg->data) {
	for (j = regs->num - 1; j >= i; j--)
	memcpy(&regs->reg[j + 1], &regs->reg[j],
	sizeof(*reg));
	break;
	}

	/* new data overlapping registered region */
	EFI_PRINT("%s: new region already part of another\n", __func__);
	return EFI_INVALID_PARAMETER;
	}

	reg = &regs->reg[i];
	reg->data = start;
	reg->size = end - start;
	regs->num++;

	return EFI_SUCCESS;
	}

	/**
	* efi_sigstore_free - free signature store
	* @sigstore: Pointer to signature store structure
	*
	* Feee all the memories held in signature store and itself,
	* which were allocated by efi_sigstore_parse_sigdb().
	*/
	void efi_sigstore_free(struct efi_signature_store *sigstore)
	{
	struct efi_signature_store *sigstore_next;
	struct efi_sig_data sig_data, sig_data_next;

	while (sigstore) {
	sigstore_next = sigstore->next;

	sig_data = sigstore->sig_data_list;
	while (sig_data) {
	sig_data_next = sig_data->next;
	free(sig_data->data);
	free(sig_data);
	sig_data = sig_data_next;
	}

	free(sigstore);
	sigstore = sigstore_next;
	}
	}

	/**
	* efi_sigstore_parse_siglist - parse a signature list
	* @name: Pointer to signature list
	*
	* Parse signature list and instantiate a signature store structure.
	* Signature database is a simple concatenation of one or more
	* signature list(s).
	*
	* Return: Pointer to signature store on success, NULL on error
	*/
	static struct efi_signature_store *
	efi_sigstore_parse_siglist(struct efi_signature_list *esl)
	{
	struct efi_signature_store *siglist = NULL;
	struct efi_sig_data sig_data, sig_data_next;
	struct efi_signature_data *esd;
	size_t left;

	/*
	* UEFI specification defines certificate types:
	* for non-signed images,
	* EFI_CERT_SHA256_GUID
	* EFI_CERT_RSA2048_GUID
	* EFI_CERT_RSA2048_SHA256_GUID
	* EFI_CERT_SHA1_GUID
	* EFI_CERT_RSA2048_SHA_GUID
	* EFI_CERT_SHA224_GUID
	* EFI_CERT_SHA384_GUID
	* EFI_CERT_SHA512_GUID
	*
	* for signed images,
	* EFI_CERT_X509_GUID
	* NOTE: Each certificate will normally be in a separate
	* EFI_SIGNATURE_LIST as the size may vary depending on
	* its algo's.
	*
	* for timestamp revocation of certificate,
	* EFI_CERT_X509_SHA512_GUID
	* EFI_CERT_X509_SHA256_GUID
	* EFI_CERT_X509_SHA384_GUID
	*/

	if (esl->signature_list_size
	<= (sizeof(*esl) + esl->signature_header_size)) {
	EFI_PRINT("Siglist in wrong format\n");
	return NULL;
	}

	/* Create a head */
	siglist = calloc(sizeof(*siglist), 1);
	if (!siglist) {
	EFI_PRINT("Out of memory\n");
	goto err;
	}
	memcpy(&siglist->sig_type, &esl->signature_type, sizeof(efi_guid_t));

	/* Go through the list */
	sig_data_next = NULL;
	left = esl->signature_list_size
	- (sizeof(*esl) + esl->signature_header_size);
	esd = (struct efi_signature_data *)
	((u8 )esl + sizeof(esl) + esl->signature_header_size);

	while (left > 0) {
	/* Signature must exist if there is remaining data. */
	if (left < esl->signature_size) {
	EFI_PRINT("Certificate is too small\n");
	goto err;
	}

	sig_data = calloc(esl->signature_size
	- sizeof(esd->signature_owner), 1);
	if (!sig_data) {
	EFI_PRINT("Out of memory\n");
	goto err;
	}

	/* Append signature data */
	memcpy(&sig_data->owner, &esd->signature_owner,
	sizeof(efi_guid_t));
	sig_data->size = esl->signature_size
	- sizeof(esd->signature_owner);
	sig_data->data = malloc(sig_data->size);
	if (!sig_data->data) {
	EFI_PRINT("Out of memory\n");
	goto err;
	}
	memcpy(sig_data->data, esd->signature_data, sig_data->size);

	sig_data->next = sig_data_next;
	sig_data_next = sig_data;

	/* Next */
	esd = (struct efi_signature_data *)
	((u8 *)esd + esl->signature_size);
	left -= esl->signature_size;
	}
	siglist->sig_data_list = sig_data_next;

	return siglist;

	err:
	efi_sigstore_free(siglist);

	return NULL;
	}

	/**
	* efi_sigstore_parse_sigdb - parse a signature database variable
	* @name: Variable's name
	*
	* Read in a value of signature database variable pointed to by
	* @name, parse it and instantiate a signature store structure.
	*
	* Return: Pointer to signature store on success, NULL on error
	*/
	struct efi_signature_store efi_sigstore_parse_sigdb(u16 name)
	{
	struct efi_signature_store sigstore = NULL, siglist;
	struct efi_signature_list *esl;
	const efi_guid_t *vendor;
	void *db;
	efi_uintn_t db_size;
	efi_status_t ret;

	if (!u16_strcmp(name, L"PK") \|\| !u16_strcmp(name, L"KEK")) {
	vendor = &efi_global_variable_guid;
	} else if (!u16_strcmp(name, L"db") \|\| !u16_strcmp(name, L"dbx")) {
	vendor = &efi_guid_image_security_database;
	} else {
	EFI_PRINT("unknown signature database, %ls\n", name);
	return NULL;
	}

	/* retrieve variable data */
	db_size = 0;
	ret = EFI_CALL(efi_get_variable(name, vendor, NULL, &db_size, NULL));
	if (ret == EFI_NOT_FOUND) {
	EFI_PRINT("variable, %ls, not found\n", name);
	sigstore = calloc(sizeof(*sigstore), 1);
	return sigstore;
	} else if (ret != EFI_BUFFER_TOO_SMALL) {
	EFI_PRINT("Getting variable, %ls, failed\n", name);
	return NULL;
	}

	db = malloc(db_size);
	if (!db) {
	EFI_PRINT("Out of memory\n");
	return NULL;
	}

	ret = EFI_CALL(efi_get_variable(name, vendor, NULL, &db_size, db));
	if (ret != EFI_SUCCESS) {
	EFI_PRINT("Getting variable, %ls, failed\n", name);
	goto err;
	}

	/* Parse siglist list */
	esl = db;
	while (db_size > 0) {
	/* List must exist if there is remaining data. */
	if (db_size < sizeof(*esl)) {
	EFI_PRINT("variable, %ls, in wrong format\n", name);
	goto err;
	}

	if (db_size < esl->signature_list_size) {
	EFI_PRINT("variable, %ls, in wrong format\n", name);
	goto err;
	}

	/* Parse a single siglist. */
	siglist = efi_sigstore_parse_siglist(esl);
	if (!siglist) {
	EFI_PRINT("Parsing signature list of %ls failed\n",
	name);
	goto err;
	}

	/* Append siglist */
	siglist->next = sigstore;
	sigstore = siglist;

	/* Next */
	db_size -= esl->signature_list_size;
	esl = (void *)esl + esl->signature_list_size;
	}
	free(db);

	return sigstore;

	err:
	efi_sigstore_free(sigstore);
	free(db);

	return NULL;
	}
	#endif /* CONFIG_EFI_SECURE_BOOT */