1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright 2021 Google LLC
  4 *
  5 * sysfs support for blk-crypto.  This file contains the code which exports the
  6 * crypto capabilities of devices via /sys/block/$disk/queue/crypto/.
  7 */
  8
  9#include <linux/blk-crypto-profile.h>
 10
 11#include "blk-crypto-internal.h"
 12
 13struct blk_crypto_kobj {
 14	struct kobject kobj;
 15	struct blk_crypto_profile *profile;
 16};
 17
 18struct blk_crypto_attr {
 19	struct attribute attr;
 20	ssize_t (*show)(struct blk_crypto_profile *profile,
 21			struct blk_crypto_attr *attr, char *page);
 22};
 23
 24static struct blk_crypto_profile *kobj_to_crypto_profile(struct kobject *kobj)
 25{
 26	return container_of(kobj, struct blk_crypto_kobj, kobj)->profile;
 27}
 28
 29static struct blk_crypto_attr *attr_to_crypto_attr(struct attribute *attr)
 30{
 31	return container_of(attr, struct blk_crypto_attr, attr);
 32}
 33
 34static ssize_t max_dun_bits_show(struct blk_crypto_profile *profile,
 35				 struct blk_crypto_attr *attr, char *page)
 36{
 37	return sysfs_emit(page, "%u\n", 8 * profile->max_dun_bytes_supported);
 38}
 39
 40static ssize_t num_keyslots_show(struct blk_crypto_profile *profile,
 41				 struct blk_crypto_attr *attr, char *page)
 42{
 43	return sysfs_emit(page, "%u\n", profile->num_slots);
 44}
 45
 46#define BLK_CRYPTO_RO_ATTR(_name) \
 47	static struct blk_crypto_attr _name##_attr = __ATTR_RO(_name)
 48
 49BLK_CRYPTO_RO_ATTR(max_dun_bits);
 50BLK_CRYPTO_RO_ATTR(num_keyslots);
 51
 52static struct attribute *blk_crypto_attrs[] = {
 53	&max_dun_bits_attr.attr,
 54	&num_keyslots_attr.attr,
 55	NULL,
 56};
 57
 58static const struct attribute_group blk_crypto_attr_group = {
 59	.attrs = blk_crypto_attrs,
 60};
 61
 62/*
 63 * The encryption mode attributes.  To avoid hard-coding the list of encryption
 64 * modes, these are initialized at boot time by blk_crypto_sysfs_init().
 65 */
 66static struct blk_crypto_attr __blk_crypto_mode_attrs[BLK_ENCRYPTION_MODE_MAX];
 67static struct attribute *blk_crypto_mode_attrs[BLK_ENCRYPTION_MODE_MAX + 1];
 68
 69static umode_t blk_crypto_mode_is_visible(struct kobject *kobj,
 70					  struct attribute *attr, int n)
 71{
 72	struct blk_crypto_profile *profile = kobj_to_crypto_profile(kobj);
 73	struct blk_crypto_attr *a = attr_to_crypto_attr(attr);
 74	int mode_num = a - __blk_crypto_mode_attrs;
 75
 76	if (profile->modes_supported[mode_num])
 77		return 0444;
 78	return 0;
 79}
 80
 81static ssize_t blk_crypto_mode_show(struct blk_crypto_profile *profile,
 82				    struct blk_crypto_attr *attr, char *page)
 83{
 84	int mode_num = attr - __blk_crypto_mode_attrs;
 85
 86	return sysfs_emit(page, "0x%x\n", profile->modes_supported[mode_num]);
 87}
 88
 89static const struct attribute_group blk_crypto_modes_attr_group = {
 90	.name = "modes",
 91	.attrs = blk_crypto_mode_attrs,
 92	.is_visible = blk_crypto_mode_is_visible,
 93};
 94
 95static const struct attribute_group *blk_crypto_attr_groups[] = {
 96	&blk_crypto_attr_group,
 97	&blk_crypto_modes_attr_group,
 98	NULL,
 99};
100
101static ssize_t blk_crypto_attr_show(struct kobject *kobj,
102				    struct attribute *attr, char *page)
103{
104	struct blk_crypto_profile *profile = kobj_to_crypto_profile(kobj);
105	struct blk_crypto_attr *a = attr_to_crypto_attr(attr);
106
107	return a->show(profile, a, page);
108}
109
110static const struct sysfs_ops blk_crypto_attr_ops = {
111	.show = blk_crypto_attr_show,
112};
113
114static void blk_crypto_release(struct kobject *kobj)
115{
116	kfree(container_of(kobj, struct blk_crypto_kobj, kobj));
117}
118
119static const struct kobj_type blk_crypto_ktype = {
120	.default_groups = blk_crypto_attr_groups,
121	.sysfs_ops	= &blk_crypto_attr_ops,
122	.release	= blk_crypto_release,
123};
124
125/*
126 * If the request_queue has a blk_crypto_profile, create the "crypto"
127 * subdirectory in sysfs (/sys/block/$disk/queue/crypto/).
128 */
129int blk_crypto_sysfs_register(struct gendisk *disk)
130{
131	struct request_queue *q = disk->queue;
132	struct blk_crypto_kobj *obj;
133	int err;
134
135	if (!q->crypto_profile)
136		return 0;
137
138	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
139	if (!obj)
140		return -ENOMEM;
141	obj->profile = q->crypto_profile;
142
143	err = kobject_init_and_add(&obj->kobj, &blk_crypto_ktype,
144				   &disk->queue_kobj, "crypto");
145	if (err) {
146		kobject_put(&obj->kobj);
147		return err;
148	}
149	q->crypto_kobject = &obj->kobj;
150	return 0;
151}
152
153void blk_crypto_sysfs_unregister(struct gendisk *disk)
154{
155	kobject_put(disk->queue->crypto_kobject);
156}
157
158static int __init blk_crypto_sysfs_init(void)
159{
160	int i;
161
162	BUILD_BUG_ON(BLK_ENCRYPTION_MODE_INVALID != 0);
163	for (i = 1; i < BLK_ENCRYPTION_MODE_MAX; i++) {
164		struct blk_crypto_attr *attr = &__blk_crypto_mode_attrs[i];
165
166		attr->attr.name = blk_crypto_modes[i].name;
167		attr->attr.mode = 0444;
168		attr->show = blk_crypto_mode_show;
169		blk_crypto_mode_attrs[i - 1] = &attr->attr;
170	}
171	return 0;
172}
173subsys_initcall(blk_crypto_sysfs_init);