Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Nayna Jain | 1017 | 100.00% | 1 | 100.00% |
Total | 1017 | 1 |
// 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);
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