Re: [PATCH v3 4/4] powerpc: load firmware trusted keys/hashes into kernel keyring
From: Mimi Zohar <zohar@linux.ibm.com>
Date: 2019-09-03 22:55:06
Also in:
linux-efi, linux-integrity, lkml
On Mon, 2019-08-26 at 09:23 -0400, Nayna Jain wrote:
The keys used to verify the Host OS kernel are managed by firmware as secure variables. This patch loads the verification keys into the .platform keyring and revocation hashes into .blacklist keyring. This enables verification and loading of the kernels signed by the boot time keys which are trusted by firmware. Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Feel free to add my tag after addressing the formatting issues. Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
quoted hunk ↗ jump to hunk
diff --git a/security/integrity/platform_certs/load_powerpc.c b/security/integrity/platform_certs/load_powerpc.c new file mode 100644 index 000000000000..359d5063d4da --- /dev/null +++ b/security/integrity/platform_certs/load_powerpc.c@@ -0,0 +1,88 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 IBM Corporation + * Author: Nayna Jain <nayna@linux.ibm.com> + * + * - loads keys and hashes stored and controlled by the firmware. + */ +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/cred.h> +#include <linux/err.h> +#include <linux/slab.h> +#include <asm/secboot.h> +#include <asm/secvar.h> +#include "keyring_handler.h" + +/* + * Get a certificate list blob from the named secure variable. + */ +static __init void *get_cert_list(u8 *key, unsigned long keylen, uint64_t *size) +{ + int rc; + void *db; + + rc = secvar_ops->get(key, keylen, NULL, size); + if (rc) { + pr_err("Couldn't get size: %d\n", rc); + return NULL; + } + + db = kmalloc(*size, GFP_KERNEL); + if (!db) + return NULL; + + rc = secvar_ops->get(key, keylen, db, size); + if (rc) { + kfree(db); + pr_err("Error reading db var: %d\n", rc); + return NULL; + } + + return db; +} + +/* + * Load the certs contained in the keys databases into the platform trusted + * keyring and the blacklisted X.509 cert SHA256 hashes into the blacklist + * keyring. + */ +static int __init load_powerpc_certs(void) +{ + void *db = NULL, *dbx = NULL; + uint64_t dbsize = 0, dbxsize = 0; + int rc = 0; + + if (!secvar_ops) + return -ENODEV; + + /* Get db, and dbx. They might not exist, so it isn't + * an error if we can't get them. + */ + db = get_cert_list("db", 3, &dbsize); + if (!db) { + pr_err("Couldn't get db list from firmware\n"); + } else { + rc = parse_efi_signature_list("powerpc:db", + db, dbsize, get_handler_for_db); + if (rc) + pr_err("Couldn't parse db signatures: %d\n", + rc);
There's no need to split this line.
+ kfree(db);
+ }
+
+ dbx = get_cert_list("dbx", 3, &dbxsize);
+ if (!dbx) {
+ pr_info("Couldn't get dbx list from firmware\n");
+ } else {
+ rc = parse_efi_signature_list("powerpc:dbx",
+ dbx, dbxsize,
+ get_handler_for_dbx);Formatting of this line is off.
+ if (rc)
+ pr_err("Couldn't parse dbx signatures: %d\n", rc);
+ kfree(dbx);
+ }
+
+ return rc;
+}
+late_initcall(load_powerpc_certs);