Commit 28a51ee8 authored by Steffen Eiden's avatar Steffen Eiden Committed by Heiko Carstens
Browse files

s390/uv: Provide host-key hashes in sysfs 



Utilize the new Query Ultravisor Keys UVC to give user space the
information which host-keys are installed on the system.

Create a new sysfs directory 'firmware/uv/keys' that contains the hash
of the host-key and the backup host-key of that system. Additionally,
the file 'all' contains the response from the UVC possibly containing
more key-hashes than currently known.

Reviewed-by: default avatarJanosch Frank <frankja@linux.ibm.com>
Signed-off-by: default avatarSteffen Eiden <seiden@linux.ibm.com>
Link: https://lore.kernel.org/r/20241023075529.2561384-1-seiden@linux.ibm.com


Signed-off-by: default avatarJanosch Frank <frankja@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
parent bb4ad73a

arch/s390/include/asm/uv.h

+17 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#define UVC_RC_NEED_DESTROY	0x8000



#define UVC_CMD_QUI			0x0001

#define UVC_CMD_QUERY_KEYS		0x0002

#define UVC_CMD_INIT_UV			0x000f

#define UVC_CMD_CREATE_SEC_CONF		0x0100

#define UVC_CMD_DESTROY_SEC_CONF	0x0101
@@ -94,6 +95,7 @@ enum uv_cmds_inst { 
	BIT_UVC_CMD_ADD_SECRET = 29,

	BIT_UVC_CMD_LIST_SECRETS = 30,

	BIT_UVC_CMD_LOCK_SECRETS = 31,

	BIT_UVC_CMD_QUERY_KEYS = 34,

};



enum uv_feat_ind {
@@ -145,6 +147,21 @@ struct uv_cb_qui { 
	u8 reserved112[0x120 - 0x112];		/* 0x0112 */

} __packed __aligned(8);



struct uv_key_hash {

	u64 dword[4];

} __packed __aligned(8);



#define UVC_QUERY_KEYS_IDX_HK		0

#define UVC_QUERY_KEYS_IDX_BACK_HK	1



/* Query Ultravisor Keys */

struct uv_cb_query_keys {

	struct uv_cb_header header;		/* 0x0000 */

	u64 reserved08[3];			/* 0x0008 */

	struct uv_key_hash key_hashes[15];	/* 0x0020 */

} __packed __aligned(8);

static_assert(sizeof(struct uv_cb_query_keys) == 0x200);



/* Initialize Ultravisor */

struct uv_cb_init {

	struct uv_cb_header header;

arch/s390/kernel/uv.c

+71 −0
Original line number Diff line number Diff line
@@ -722,10 +722,76 @@ static struct attribute *uv_query_attrs[] = { 
	NULL,

};



static inline struct uv_cb_query_keys uv_query_keys(void)

{

	struct uv_cb_query_keys uvcb = {

		.header.cmd = UVC_CMD_QUERY_KEYS,

		.header.len = sizeof(uvcb)

	};



	uv_call(0, (uint64_t)&uvcb);

	return uvcb;

}



static inline ssize_t emit_hash(struct uv_key_hash *hash, char *buf, int at)

{

	return sysfs_emit_at(buf, at, "%016llx%016llx%016llx%016llx\n",

			    hash->dword[0], hash->dword[1], hash->dword[2], hash->dword[3]);

}



static ssize_t uv_keys_host_key(struct kobject *kobj,

				struct kobj_attribute *attr, char *buf)

{

	struct uv_cb_query_keys uvcb = uv_query_keys();



	return emit_hash(&uvcb.key_hashes[UVC_QUERY_KEYS_IDX_HK], buf, 0);

}



static struct kobj_attribute uv_keys_host_key_attr =

	__ATTR(host_key, 0444, uv_keys_host_key, NULL);



static ssize_t uv_keys_backup_host_key(struct kobject *kobj,

				       struct kobj_attribute *attr, char *buf)

{

	struct uv_cb_query_keys uvcb = uv_query_keys();



	return emit_hash(&uvcb.key_hashes[UVC_QUERY_KEYS_IDX_BACK_HK], buf, 0);

}



static struct kobj_attribute uv_keys_backup_host_key_attr =

	__ATTR(backup_host_key, 0444, uv_keys_backup_host_key, NULL);



static ssize_t uv_keys_all(struct kobject *kobj,

			   struct kobj_attribute *attr, char *buf)

{

	struct uv_cb_query_keys uvcb = uv_query_keys();

	ssize_t len = 0;

	int i;



	for (i = 0; i < ARRAY_SIZE(uvcb.key_hashes); i++)

		len += emit_hash(uvcb.key_hashes + i, buf, len);



	return len;

}



static struct kobj_attribute uv_keys_all_attr =

	__ATTR(all, 0444, uv_keys_all, NULL);



static struct attribute_group uv_query_attr_group = {

	.attrs = uv_query_attrs,

};



static struct attribute *uv_keys_attrs[] = {

	&uv_keys_host_key_attr.attr,

	&uv_keys_backup_host_key_attr.attr,

	&uv_keys_all_attr.attr,

	NULL,

};



static struct attribute_group uv_keys_attr_group = {

	.attrs = uv_keys_attrs,

};



static ssize_t uv_is_prot_virt_guest(struct kobject *kobj,

				     struct kobj_attribute *attr, char *buf)

{
@@ -751,6 +817,7 @@ static const struct attribute *uv_prot_virt_attrs[] = { 
};



static struct kset *uv_query_kset;

static struct kset *uv_keys_kset;

static struct kobject *uv_kobj;



static int __init uv_sysfs_dir_init(const struct attribute_group *grp,
@@ -789,6 +856,10 @@ static int __init uv_sysfs_init(void) 
	if (rc)

		goto out_ind_files;



	/* Get installed key hashes if available, ignore any errors */

	if (test_bit_inv(BIT_UVC_CMD_QUERY_KEYS, uv_info.inst_calls_list))

		uv_sysfs_dir_init(&uv_keys_attr_group, &uv_keys_kset, "keys");



	return 0;



out_ind_files: