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- // 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.h>
- #include <crypto/pkcs7_parser.h>
- #include <crypto/public_key.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: Array of regions
- * @count: Number 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 image_region *regs, int count,
- void **hash, size_t *size)
- {
- if (!*hash) {
- *hash = calloc(1, SHA256_SUM_LEN);
- if (!*hash) {
- EFI_PRINT("Out of memory\n");
- return false;
- }
- }
- if (size)
- *size = SHA256_SUM_LEN;
- hash_calculate("sha256", regs, count, *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_signature_lookup_digest - search for an image's digest in sigdb
- * @regs: List of regions to be authenticated
- * @db: Signature database for trusted certificates
- *
- * A message digest of image pointed to by @regs is calculated and
- * its hash value is compared to entries in signature database pointed
- * to by @db.
- *
- * Return: true if found, false if not
- */
- bool efi_signature_lookup_digest(struct efi_image_regions *regs,
- struct efi_signature_store *db)
- {
- struct efi_signature_store *siglist;
- struct efi_sig_data *sig_data;
- void *hash = NULL;
- size_t size = 0;
- bool found = false;
- EFI_PRINT("%s: Enter, %p, %p\n", __func__, regs, db);
- if (!regs || !db || !db->sig_data_list)
- goto out;
- for (siglist = db; siglist; siglist = siglist->next) {
- /* 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);
- break;
- }
- if (!efi_hash_regions(regs->reg, regs->num, &hash, &size)) {
- EFI_PRINT("Digesting an image failed\n");
- break;
- }
- 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)) {
- found = true;
- free(hash);
- goto out;
- }
- }
- free(hash);
- hash = NULL;
- }
- out:
- EFI_PRINT("%s: Exit, found: %d\n", __func__, found);
- return found;
- }
- /**
- * efi_lookup_certificate - find a certificate within db
- * @msg: Signature
- * @db: Signature database
- *
- * Search signature database pointed to by @db and find a certificate
- * pointed to by @cert.
- *
- * Return: true if found, false otherwise.
- */
- static bool efi_lookup_certificate(struct x509_certificate *cert,
- struct efi_signature_store *db)
- {
- struct efi_signature_store *siglist;
- struct efi_sig_data *sig_data;
- struct image_region reg[1];
- void *hash = NULL, *hash_tmp = NULL;
- size_t size = 0;
- bool found = false;
- EFI_PRINT("%s: Enter, %p, %p\n", __func__, cert, db);
- if (!cert || !db || !db->sig_data_list)
- goto out;
- /*
- * TODO: identify a certificate using sha256 digest
- * Is there any better way?
- */
- /* calculate hash of TBSCertificate */
- reg[0].data = cert->tbs;
- reg[0].size = cert->tbs_size;
- if (!efi_hash_regions(reg, 1, &hash, &size))
- goto out;
- EFI_PRINT("%s: searching for %s\n", __func__, cert->subject);
- for (siglist = db; siglist; siglist = siglist->next) {
- /* only with x509 certificate */
- if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509))
- continue;
- for (sig_data = siglist->sig_data_list; sig_data;
- sig_data = sig_data->next) {
- struct x509_certificate *cert_tmp;
- cert_tmp = x509_cert_parse(sig_data->data,
- sig_data->size);
- if (IS_ERR_OR_NULL(cert_tmp))
- continue;
- EFI_PRINT("%s: against %s\n", __func__,
- cert_tmp->subject);
- reg[0].data = cert_tmp->tbs;
- reg[0].size = cert_tmp->tbs_size;
- if (!efi_hash_regions(reg, 1, &hash_tmp, NULL))
- goto out;
- x509_free_certificate(cert_tmp);
- if (!memcmp(hash, hash_tmp, size)) {
- found = true;
- goto out;
- }
- }
- }
- out:
- free(hash);
- free(hash_tmp);
- EFI_PRINT("%s: Exit, found: %d\n", __func__, found);
- return found;
- }
- /**
- * efi_verify_certificate - verify certificate's signature with database
- * @signer: Certificate
- * @db: Signature database
- * @root: Certificate to verify @signer
- *
- * Determine if certificate pointed to by @signer may be verified
- * by one of certificates in signature database pointed to by @db.
- *
- * Return: true if certificate is verified, false otherwise.
- */
- static bool efi_verify_certificate(struct x509_certificate *signer,
- struct efi_signature_store *db,
- struct x509_certificate **root)
- {
- struct efi_signature_store *siglist;
- struct efi_sig_data *sig_data;
- struct x509_certificate *cert;
- bool verified = false;
- int ret;
- EFI_PRINT("%s: Enter, %p, %p\n", __func__, signer, db);
- if (!signer || !db || !db->sig_data_list)
- goto out;
- for (siglist = db; siglist; siglist = siglist->next) {
- /* only with x509 certificate */
- if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509))
- continue;
- for (sig_data = siglist->sig_data_list; sig_data;
- sig_data = sig_data->next) {
- cert = x509_cert_parse(sig_data->data, sig_data->size);
- if (IS_ERR_OR_NULL(cert)) {
- EFI_PRINT("Cannot parse x509 certificate\n");
- continue;
- }
- ret = public_key_verify_signature(cert->pub,
- signer->sig);
- if (!ret) {
- verified = true;
- if (root)
- *root = cert;
- else
- x509_free_certificate(cert);
- goto out;
- }
- x509_free_certificate(cert);
- }
- }
- out:
- EFI_PRINT("%s: Exit, verified: %d\n", __func__, verified);
- return verified;
- }
- /**
- * efi_signature_check_revocation - check revocation with dbx
- * @sinfo: Signer's info
- * @cert: x509 certificate
- * @dbx: Revocation signature database
- *
- * Search revocation signature database pointed to by @dbx and find
- * an entry matching to certificate pointed to by @cert.
- *
- * While this entry contains revocation time, we don't support timestamp
- * protocol at this time and any image will be unconditionally revoked
- * when this match occurs.
- *
- * Return: true if check passed (not found), false otherwise.
- */
- static bool efi_signature_check_revocation(struct pkcs7_signed_info *sinfo,
- struct x509_certificate *cert,
- struct efi_signature_store *dbx)
- {
- struct efi_signature_store *siglist;
- struct efi_sig_data *sig_data;
- struct image_region reg[1];
- void *hash = NULL;
- size_t size = 0;
- time64_t revoc_time;
- bool revoked = false;
- EFI_PRINT("%s: Enter, %p, %p, %p\n", __func__, sinfo, cert, dbx);
- if (!sinfo || !cert || !dbx || !dbx->sig_data_list)
- goto out;
- EFI_PRINT("Checking revocation against %s\n", cert->subject);
- for (siglist = dbx; siglist; siglist = siglist->next) {
- if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509_sha256))
- continue;
- /* calculate hash of TBSCertificate */
- reg[0].data = cert->tbs;
- reg[0].size = cert->tbs_size;
- if (!efi_hash_regions(reg, 1, &hash, &size))
- goto out;
- 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;
- * };
- */
- #ifdef DEBUG
- if (sig_data->size >= size) {
- EFI_PRINT("hash in db:\n");
- print_hex_dump(" ", DUMP_PREFIX_OFFSET,
- 16, 1,
- sig_data->data, size, false);
- }
- #endif
- if ((sig_data->size < size + sizeof(time64_t)) ||
- memcmp(sig_data->data, hash, size))
- continue;
- memcpy(&revoc_time, sig_data->data + size,
- sizeof(revoc_time));
- EFI_PRINT("revocation time: 0x%llx\n", revoc_time);
- /*
- * TODO: compare signing timestamp in sinfo
- * with revocation time
- */
- revoked = true;
- free(hash);
- goto out;
- }
- free(hash);
- hash = NULL;
- }
- out:
- EFI_PRINT("%s: Exit, revoked: %d\n", __func__, revoked);
- return !revoked;
- }
- /*
- * efi_signature_verify - verify signatures with db and dbx
- * @regs: List of regions to be authenticated
- * @msg: Signature
- * @db: Signature database for trusted certificates
- * @dbx: Revocation signature database
- *
- * All the signature pointed to by @msg against image pointed to by @regs
- * will be verified by signature database pointed to by @db and @dbx.
- *
- * Return: true if verification for all signatures passed, false otherwise
- */
- bool efi_signature_verify(struct efi_image_regions *regs,
- struct pkcs7_message *msg,
- struct efi_signature_store *db,
- struct efi_signature_store *dbx)
- {
- struct pkcs7_signed_info *sinfo;
- struct x509_certificate *signer, *root;
- bool verified = false;
- int ret;
- EFI_PRINT("%s: Enter, %p, %p, %p, %p\n", __func__, regs, msg, db, dbx);
- if (!regs || !msg || !db || !db->sig_data_list)
- goto out;
- for (sinfo = msg->signed_infos; sinfo; sinfo = sinfo->next) {
- EFI_PRINT("Signed Info: digest algo: %s, pkey algo: %s\n",
- sinfo->sig->hash_algo, sinfo->sig->pkey_algo);
- /*
- * only for authenticated variable.
- *
- * If this function is called for image,
- * hash calculation will be done in
- * pkcs7_verify_one().
- */
- if (!msg->data &&
- !efi_hash_regions(regs->reg, regs->num,
- (void **)&sinfo->sig->digest, NULL)) {
- EFI_PRINT("Digesting an image failed\n");
- goto out;
- }
- EFI_PRINT("Verifying certificate chain\n");
- signer = NULL;
- ret = pkcs7_verify_one(msg, sinfo, &signer);
- if (ret == -ENOPKG)
- continue;
- if (ret < 0 || !signer)
- goto out;
- if (sinfo->blacklisted)
- goto out;
- EFI_PRINT("Verifying last certificate in chain\n");
- if (signer->self_signed) {
- if (efi_lookup_certificate(signer, db))
- if (efi_signature_check_revocation(sinfo,
- signer, dbx))
- break;
- } else if (efi_verify_certificate(signer, db, &root)) {
- bool check;
- check = efi_signature_check_revocation(sinfo, root,
- dbx);
- x509_free_certificate(root);
- if (check)
- break;
- }
- EFI_PRINT("Certificate chain didn't reach trusted CA\n");
- }
- if (sinfo)
- verified = true;
- out:
- EFI_PRINT("%s: Exit, verified: %d\n", __func__, verified);
- return verified;
- }
- /**
- * efi_signature_check_signers - check revocation against all signers with dbx
- * @msg: Signature
- * @dbx: Revocation signature database
- *
- * Determine if none of signers' certificates in @msg are revoked
- * by signature database pointed to by @dbx.
- *
- * Return: true if all signers passed, false otherwise.
- */
- bool efi_signature_check_signers(struct pkcs7_message *msg,
- struct efi_signature_store *dbx)
- {
- struct pkcs7_signed_info *sinfo;
- bool revoked = false;
- EFI_PRINT("%s: Enter, %p, %p\n", __func__, msg, dbx);
- if (!msg || !dbx)
- goto out;
- for (sinfo = msg->signed_infos; sinfo; sinfo = sinfo->next) {
- if (sinfo->signer &&
- !efi_signature_check_revocation(sinfo, sinfo->signer,
- dbx)) {
- revoked = true;
- break;
- }
- }
- out:
- EFI_PRINT("%s: Exit, revoked: %d\n", __func__, revoked);
- return !revoked;
- }
- /**
- * 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 = ®s->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(®s->reg[j + 1], ®s->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 = ®s->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 */
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