114 lines
2.6 KiB
C
114 lines
2.6 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2019 IBM Corporation
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* Author: Nayna Jain
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*
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* - loads keys and hashes stored and controlled by the firmware.
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/cred.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <asm/secure_boot.h>
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#include <asm/secvar.h>
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#include "keyring_handler.h"
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#include "../integrity.h"
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/*
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* Get a certificate list blob from the named secure variable.
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*
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* Returns:
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* - a pointer to a kmalloc'd buffer containing the cert list on success
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* - NULL if the key does not exist
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* - an ERR_PTR on error
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*/
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static __init void *get_cert_list(u8 *key, unsigned long keylen, u64 *size)
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{
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int rc;
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void *db;
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rc = secvar_ops->get(key, keylen, NULL, size);
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if (rc) {
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if (rc == -ENOENT)
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return NULL;
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return ERR_PTR(rc);
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}
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db = kmalloc(*size, GFP_KERNEL);
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if (!db)
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return ERR_PTR(-ENOMEM);
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rc = secvar_ops->get(key, keylen, db, size);
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if (rc) {
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kfree(db);
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return ERR_PTR(rc);
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}
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return db;
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}
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/*
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* Load the certs contained in the keys databases into the platform trusted
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* keyring and the blacklisted X.509 cert SHA256 hashes into the blacklist
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* keyring.
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*/
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static int __init load_powerpc_certs(void)
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{
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void *db = NULL, *dbx = NULL;
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u64 dbsize = 0, dbxsize = 0;
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int rc = 0;
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ssize_t len;
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char buf[32];
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if (!secvar_ops)
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return -ENODEV;
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len = secvar_ops->format(buf, sizeof(buf));
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if (len <= 0)
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return -ENODEV;
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// Check for known secure boot implementations from OPAL or PLPKS
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if (strcmp("ibm,edk2-compat-v1", buf) && strcmp("ibm,plpks-sb-v1", buf)) {
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pr_err("Unsupported secvar implementation \"%s\", not loading certs\n", buf);
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return -ENODEV;
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}
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/*
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* Get db, and dbx. They might not exist, so it isn't an error if we
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* can't get them.
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*/
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db = get_cert_list("db", 3, &dbsize);
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if (!db) {
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pr_info("Couldn't get db list from firmware\n");
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} else if (IS_ERR(db)) {
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rc = PTR_ERR(db);
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pr_err("Error reading db from firmware: %d\n", rc);
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return rc;
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} else {
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rc = parse_efi_signature_list("powerpc:db", db, dbsize,
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get_handler_for_db);
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if (rc)
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pr_err("Couldn't parse db signatures: %d\n", rc);
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kfree(db);
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}
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dbx = get_cert_list("dbx", 4, &dbxsize);
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if (!dbx) {
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pr_info("Couldn't get dbx list from firmware\n");
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} else if (IS_ERR(dbx)) {
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rc = PTR_ERR(dbx);
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pr_err("Error reading dbx from firmware: %d\n", rc);
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return rc;
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} else {
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rc = parse_efi_signature_list("powerpc:dbx", dbx, dbxsize,
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get_handler_for_dbx);
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if (rc)
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pr_err("Couldn't parse dbx signatures: %d\n", rc);
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kfree(dbx);
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}
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return rc;
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}
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late_initcall(load_powerpc_certs);
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