diff options
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/Makefile | 3 | ||||
| -rw-r--r-- | arch/powerpc/kernel/ima_arch.c | 78 | ||||
| -rw-r--r-- | arch/powerpc/kernel/secure_boot.c | 50 | ||||
| -rw-r--r-- | arch/powerpc/kernel/secvar-ops.c | 17 | ||||
| -rw-r--r-- | arch/powerpc/kernel/secvar-sysfs.c | 248 |
5 files changed, 396 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index 717b52b65d62..bb57d168d6f4 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -160,6 +160,9 @@ ifneq ($(CONFIG_PPC_POWERNV)$(CONFIG_PPC_SVM),) obj-y += ucall.o endif +obj-$(CONFIG_PPC_SECURE_BOOT) += secure_boot.o ima_arch.o secvar-ops.o +obj-$(CONFIG_PPC_SECVAR_SYSFS) += secvar-sysfs.o + # Disable GCOV, KCOV & sanitizers in odd or sensitive code GCOV_PROFILE_prom_init.o := n KCOV_INSTRUMENT_prom_init.o := n diff --git a/arch/powerpc/kernel/ima_arch.c b/arch/powerpc/kernel/ima_arch.c new file mode 100644 index 000000000000..e34116255ced --- /dev/null +++ b/arch/powerpc/kernel/ima_arch.c @@ -0,0 +1,78 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 IBM Corporation + * Author: Nayna Jain + */ + +#include <linux/ima.h> +#include <asm/secure_boot.h> + +bool arch_ima_get_secureboot(void) +{ + return is_ppc_secureboot_enabled(); +} + +/* + * The "secure_rules" are enabled only on "secureboot" enabled systems. + * These rules verify the file signatures against known good values. + * The "appraise_type=imasig|modsig" option allows the known good signature + * to be stored as an xattr or as an appended signature. + * + * To avoid duplicate signature verification as much as possible, the IMA + * policy rule for module appraisal is added only if CONFIG_MODULE_SIG_FORCE + * is not enabled. + */ +static const char *const secure_rules[] = { + "appraise func=KEXEC_KERNEL_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig", +#ifndef CONFIG_MODULE_SIG_FORCE + "appraise func=MODULE_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig", +#endif + NULL +}; + +/* + * The "trusted_rules" are enabled only on "trustedboot" enabled systems. + * These rules add the kexec kernel image and kernel modules file hashes to + * the IMA measurement list. + */ +static const char *const trusted_rules[] = { + "measure func=KEXEC_KERNEL_CHECK", + "measure func=MODULE_CHECK", + NULL +}; + +/* + * The "secure_and_trusted_rules" contains rules for both the secure boot and + * trusted boot. The "template=ima-modsig" option includes the appended + * signature, when available, in the IMA measurement list. + */ +static const char *const secure_and_trusted_rules[] = { + "measure func=KEXEC_KERNEL_CHECK template=ima-modsig", + "measure func=MODULE_CHECK template=ima-modsig", + "appraise func=KEXEC_KERNEL_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig", +#ifndef CONFIG_MODULE_SIG_FORCE + "appraise func=MODULE_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig", +#endif + NULL +}; + +/* + * Returns the relevant IMA arch-specific policies based on the system secure + * boot state. + */ +const char *const *arch_get_ima_policy(void) +{ + if (is_ppc_secureboot_enabled()) { + if (IS_ENABLED(CONFIG_MODULE_SIG)) + set_module_sig_enforced(); + + if (is_ppc_trustedboot_enabled()) + return secure_and_trusted_rules; + else + return secure_rules; + } else if (is_ppc_trustedboot_enabled()) { + return trusted_rules; + } + + return NULL; +} diff --git a/arch/powerpc/kernel/secure_boot.c b/arch/powerpc/kernel/secure_boot.c new file mode 100644 index 000000000000..4b982324d368 --- /dev/null +++ b/arch/powerpc/kernel/secure_boot.c @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 IBM Corporation + * Author: Nayna Jain + */ +#include <linux/types.h> +#include <linux/of.h> +#include <asm/secure_boot.h> + +static struct device_node *get_ppc_fw_sb_node(void) +{ + static const struct of_device_id ids[] = { + { .compatible = "ibm,secureboot", }, + { .compatible = "ibm,secureboot-v1", }, + { .compatible = "ibm,secureboot-v2", }, + {}, + }; + + return of_find_matching_node(NULL, ids); +} + +bool is_ppc_secureboot_enabled(void) +{ + struct device_node *node; + bool enabled = false; + + node = get_ppc_fw_sb_node(); + enabled = of_property_read_bool(node, "os-secureboot-enforcing"); + + of_node_put(node); + + pr_info("Secure boot mode %s\n", enabled ? "enabled" : "disabled"); + + return enabled; +} + +bool is_ppc_trustedboot_enabled(void) +{ + struct device_node *node; + bool enabled = false; + + node = get_ppc_fw_sb_node(); + enabled = of_property_read_bool(node, "trusted-enabled"); + + of_node_put(node); + + pr_info("Trusted boot mode %s\n", enabled ? "enabled" : "disabled"); + + return enabled; +} diff --git a/arch/powerpc/kernel/secvar-ops.c b/arch/powerpc/kernel/secvar-ops.c new file mode 100644 index 000000000000..6a29777d6a2d --- /dev/null +++ b/arch/powerpc/kernel/secvar-ops.c @@ -0,0 +1,17 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 IBM Corporation + * Author: Nayna Jain + * + * This file initializes secvar operations for PowerPC Secureboot + */ + +#include <linux/cache.h> +#include <asm/secvar.h> + +const struct secvar_operations *secvar_ops __ro_after_init; + +void set_secvar_ops(const struct secvar_operations *ops) +{ + secvar_ops = ops; +} diff --git a/arch/powerpc/kernel/secvar-sysfs.c b/arch/powerpc/kernel/secvar-sysfs.c new file mode 100644 index 000000000000..a0a78aba2083 --- /dev/null +++ b/arch/powerpc/kernel/secvar-sysfs.c @@ -0,0 +1,248 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2019 IBM Corporation <nayna@linux.ibm.com> + * + * This code exposes secure variables to user via sysfs + */ + +#define pr_fmt(fmt) "secvar-sysfs: "fmt + +#include <linux/slab.h> +#include <linux/compat.h> +#include <linux/string.h> +#include <linux/of.h> +#include <asm/secvar.h> + +#define NAME_MAX_SIZE 1024 + +static struct kobject *secvar_kobj; +static struct kset *secvar_kset; + +static ssize_t format_show(struct kobject *kobj, struct kobj_attribute *attr, + char *buf) +{ + ssize_t rc = 0; + struct device_node *node; + const char *format; + + node = of_find_compatible_node(NULL, NULL, "ibm,secvar-backend"); + if (!of_device_is_available(node)) + return -ENODEV; + + rc = of_property_read_string(node, "format", &format); + if (rc) + return rc; + + rc = sprintf(buf, "%s\n", format); + + of_node_put(node); + + return rc; +} + + +static ssize_t size_show(struct kobject *kobj, struct kobj_attribute *attr, + char *buf) +{ + uint64_t dsize; + int rc; + + rc = secvar_ops->get(kobj->name, strlen(kobj->name) + 1, NULL, &dsize); + if (rc) { + pr_err("Error retrieving %s variable size %d\n", kobj->name, + rc); + return rc; + } + + return sprintf(buf, "%llu\n", dsize); +} + +static ssize_t data_read(struct file *filep, struct kobject *kobj, + struct bin_attribute *attr, char *buf, loff_t off, + size_t count) +{ + uint64_t dsize; + char *data; + int rc; + + rc = secvar_ops->get(kobj->name, strlen(kobj->name) + 1, NULL, &dsize); + if (rc) { + pr_err("Error getting %s variable size %d\n", kobj->name, rc); + return rc; + } + pr_debug("dsize is %llu\n", dsize); + + data = kzalloc(dsize, GFP_KERNEL); + if (!data) + return -ENOMEM; + + rc = secvar_ops->get(kobj->name, strlen(kobj->name) + 1, data, &dsize); + if (rc) { + pr_err("Error getting %s variable %d\n", kobj->name, rc); + goto data_fail; + } + + rc = memory_read_from_buffer(buf, count, &off, data, dsize); + +data_fail: + kfree(data); + return rc; +} + +static ssize_t update_write(struct file *filep, struct kobject *kobj, + struct bin_attribute *attr, char *buf, loff_t off, + size_t count) +{ + int rc; + + pr_debug("count is %ld\n", count); + rc = secvar_ops->set(kobj->name, strlen(kobj->name) + 1, buf, count); + if (rc) { + pr_err("Error setting the %s variable %d\n", kobj->name, rc); + return rc; + } + + return count; +} + +static struct kobj_attribute format_attr = __ATTR_RO(format); + +static struct kobj_attribute size_attr = __ATTR_RO(size); + +static struct bin_attribute data_attr = __BIN_ATTR_RO(data, 0); + +static struct bin_attribute update_attr = __BIN_ATTR_WO(update, 0); + +static struct bin_attribute *secvar_bin_attrs[] = { + &data_attr, + &update_attr, + NULL, +}; + +static struct attribute *secvar_attrs[] = { + &size_attr.attr, + NULL, +}; + +static const struct attribute_group secvar_attr_group = { + .attrs = secvar_attrs, + .bin_attrs = secvar_bin_attrs, +}; +__ATTRIBUTE_GROUPS(secvar_attr); + +static struct kobj_type secvar_ktype = { + .sysfs_ops = &kobj_sysfs_ops, + .default_groups = secvar_attr_groups, +}; + +static int update_kobj_size(void) +{ + + struct device_node *node; + u64 varsize; + int rc = 0; + + node = of_find_compatible_node(NULL, NULL, "ibm,secvar-backend"); + if (!of_device_is_available(node)) { + rc = -ENODEV; + goto out; + } + + rc = of_property_read_u64(node, "max-var-size", &varsize); + if (rc) + goto out; + + data_attr.size = varsize; + update_attr.size = varsize; + +out: + of_node_put(node); + + return rc; +} + +static int secvar_sysfs_load(void) +{ + char *name; + uint64_t namesize = 0; + struct kobject *kobj; + int rc; + + name = kzalloc(NAME_MAX_SIZE, GFP_KERNEL); + if (!name) + return -ENOMEM; + + do { + rc = secvar_ops->get_next(name, &namesize, NAME_MAX_SIZE); + if (rc) { + if (rc != -ENOENT) + pr_err("error getting secvar from firmware %d\n", + rc); + break; + } + + kobj = kzalloc(sizeof(*kobj), GFP_KERNEL); + if (!kobj) { + rc = -ENOMEM; + break; + } + + kobject_init(kobj, &secvar_ktype); + + rc = kobject_add(kobj, &secvar_kset->kobj, "%s", name); + if (rc) { + pr_warn("kobject_add error %d for attribute: %s\n", rc, + name); + kobject_put(kobj); + kobj = NULL; + } + + if (kobj) + kobject_uevent(kobj, KOBJ_ADD); + + } while (!rc); + + kfree(name); + return rc; +} + +static int secvar_sysfs_init(void) +{ + int rc; + + if (!secvar_ops) { + pr_warn("secvar: failed to retrieve secvar operations.\n"); + return -ENODEV; + } + + secvar_kobj = kobject_create_and_add("secvar", firmware_kobj); + if (!secvar_kobj) { + pr_err("secvar: Failed to create firmware kobj\n"); + return -ENOMEM; + } + + rc = sysfs_create_file(secvar_kobj, &format_attr.attr); + if (rc) { + kobject_put(secvar_kobj); + return -ENOMEM; + } + + secvar_kset = kset_create_and_add("vars", NULL, secvar_kobj); + if (!secvar_kset) { + pr_err("secvar: sysfs kobject registration failed.\n"); + kobject_put(secvar_kobj); + return -ENOMEM; + } + + rc = update_kobj_size(); + if (rc) { + pr_err("Cannot read the size of the attribute\n"); + return rc; + } + + secvar_sysfs_load(); + + return 0; +} + +late_initcall(secvar_sysfs_init); |