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s390/uv: Retrieve UV secrets support

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Provide a kernel API to retrieve secrets from the UV secret store.
Add two new functions:
* `uv_get_secret_metadata` - get metadata for a given secret identifier
* `uv_retrieve_secret` - get the secret value for the secret index

With those two functions one can extract the secret for a given secret
id, if the secret is retrievable.

Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Link: https://lore.kernel.org/r/20241024084107.2418186-1-seiden@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Steffen Eiden
2024-10-24 10:41:07 +02:00
committed by Heiko Carstens
parent da59c71cc7
commit 7c9137af20
2 changed files with 262 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

136
arch/s390/include/asm/uv.h
View File

@@ -2,7 +2,7 @@
/*
* Ultravisor Interfaces
*
* Copyright IBM Corp. 2019, 2022
* Copyright IBM Corp. 2019, 2024
*
* Author(s):
* Vasily Gorbik <gor@linux.ibm.com>
@@ -63,6 +63,7 @@
#define UVC_CMD_ADD_SECRET 0x1031
#define UVC_CMD_LIST_SECRETS 0x1033
#define UVC_CMD_LOCK_SECRETS 0x1034
#define UVC_CMD_RETR_SECRET 0x1035
/* Bits in installed uv calls */
enum uv_cmds_inst {
@@ -96,6 +97,7 @@ 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_RETR_SECRET = 33,
BIT_UVC_CMD_QUERY_KEYS = 34,
};
@@ -335,7 +337,6 @@ struct uv_cb_dump_complete {
* A common UV call struct for pv guests that contains a single address
* Examples:
* Add Secret
* List Secrets
*/
struct uv_cb_guest_addr {
struct uv_cb_header header;
@@ -344,6 +345,91 @@ struct uv_cb_guest_addr {
u64 reserved28[4];
} __packed __aligned(8);
#define UVC_RC_RETR_SECR_BUF_SMALL 0x0109
#define UVC_RC_RETR_SECR_STORE_EMPTY 0x010f
#define UVC_RC_RETR_SECR_INV_IDX 0x0110
#define UVC_RC_RETR_SECR_INV_SECRET 0x0111
struct uv_cb_retr_secr {
struct uv_cb_header header;
u64 reserved08[2];
u16 secret_idx;
u16 reserved1a;
u32 buf_size;
u64 buf_addr;
u64 reserved28[4];
} __packed __aligned(8);
struct uv_cb_list_secrets {
struct uv_cb_header header;
u64 reserved08[2];
u8 reserved18[6];
u16 start_idx;
u64 list_addr;
u64 reserved28[4];
} __packed __aligned(8);
enum uv_secret_types {
UV_SECRET_INVAL = 0x0,
UV_SECRET_NULL = 0x1,
UV_SECRET_ASSOCIATION = 0x2,
UV_SECRET_PLAIN = 0x3,
UV_SECRET_AES_128 = 0x4,
UV_SECRET_AES_192 = 0x5,
UV_SECRET_AES_256 = 0x6,
UV_SECRET_AES_XTS_128 = 0x7,
UV_SECRET_AES_XTS_256 = 0x8,
UV_SECRET_HMAC_SHA_256 = 0x9,
UV_SECRET_HMAC_SHA_512 = 0xa,
/* 0x0b - 0x10 reserved */
UV_SECRET_ECDSA_P256 = 0x11,
UV_SECRET_ECDSA_P384 = 0x12,
UV_SECRET_ECDSA_P521 = 0x13,
UV_SECRET_ECDSA_ED25519 = 0x14,
UV_SECRET_ECDSA_ED448 = 0x15,
};
/**
* uv_secret_list_item_hdr - UV secret metadata.
* @index: Index of the secret in the secret list.
* @type: Type of the secret. See `enum uv_secret_types`.
* @length: Length of the stored secret.
*/
struct uv_secret_list_item_hdr {
u16 index;
u16 type;
u32 length;
} __packed __aligned(8);
#define UV_SECRET_ID_LEN 32
/**
* uv_secret_list_item - UV secret entry.
* @hdr: The metadata of this secret.
* @id: The ID of this secret, not the secret itself.
*/
struct uv_secret_list_item {
struct uv_secret_list_item_hdr hdr;
u64 reserverd08;
u8 id[UV_SECRET_ID_LEN];
} __packed __aligned(8);
/**
* uv_secret_list - UV secret-metadata list.
* @num_secr_stored: Number of secrets stored in this list.
* @total_num_secrets: Number of secrets stored in the UV for this guest.
* @next_secret_idx: positive number if there are more secrets available or zero.
* @secrets: Up to 85 UV-secret metadata entries.
*/
struct uv_secret_list {
u16 num_secr_stored;
u16 total_num_secrets;
u16 next_secret_idx;
u16 reserved_06;
u64 reserved_08;
struct uv_secret_list_item secrets[85];
} __packed __aligned(8);
static_assert(sizeof(struct uv_secret_list) == PAGE_SIZE);
static inline int __uv_call(unsigned long r1, unsigned long r2)
{
int cc;
@@ -400,6 +486,48 @@ static inline int uv_cmd_nodata(u64 handle, u16 cmd, u16 *rc, u16 *rrc)
return cc ? -EINVAL : 0;
}
/**
* uv_list_secrets() - Do a List Secrets UVC.
*
* @buf: Buffer to write list into; size of one page.
* @start_idx: The smallest index that should be included in the list.
* For the fist invocation use 0.
* @rc: Pointer to store the return code or NULL.
* @rrc: Pointer to store the return reason code or NULL.
*
* This function calls the List Secrets UVC. The result is written into `buf`,
* that needs to be at least one page of writable memory.
* `buf` consists of:
* * %struct uv_secret_list_hdr
* * %struct uv_secret_list_item (multiple)
*
* For `start_idx` use _0_ for the first call. If there are more secrets available
* but could not fit into the page then `rc` is `UVC_RC_MORE_DATA`.
* In this case use `uv_secret_list_hdr.next_secret_idx` for `start_idx`.
*
* Context: might sleep.
*
* Return: The UVC condition code.
*/
static inline int uv_list_secrets(struct uv_secret_list *buf, u16 start_idx,
u16 *rc, u16 *rrc)
{
struct uv_cb_list_secrets uvcb = {
.header.len = sizeof(uvcb),
.header.cmd = UVC_CMD_LIST_SECRETS,
.start_idx = start_idx,
.list_addr = (u64)buf,
};
int cc = uv_call_sched(0, (u64)&uvcb);
if (rc)
*rc = uvcb.header.rc;
if (rrc)
*rrc = uvcb.header.rrc;
return cc;
}
struct uv_info {
unsigned long inst_calls_list[4];
unsigned long uv_base_stor_len;
@@ -486,6 +614,10 @@ static inline int uv_remove_shared(unsigned long addr)
return share(addr, UVC_CMD_REMOVE_SHARED_ACCESS);
}
int uv_get_secret_metadata(const u8 secret_id[UV_SECRET_ID_LEN],
struct uv_secret_list_item_hdr *secret);
int uv_retrieve_secret(u16 secret_idx, u8 *buf, size_t buf_size);
extern int prot_virt_host;
static inline int is_prot_virt_host(void)

129
arch/s390/kernel/uv.c
View File

@@ -2,7 +2,7 @@
/*
* Common Ultravisor functions and initialization
*
* Copyright IBM Corp. 2019, 2020
* Copyright IBM Corp. 2019, 2024
*/
#define KMSG_COMPONENT "prot_virt"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
@@ -870,3 +870,130 @@ static int __init uv_sysfs_init(void)
return rc;
}
device_initcall(uv_sysfs_init);
/*
* Find the secret with the secret_id in the provided list.
*
* Context: might sleep.
*/
static int find_secret_in_page(const u8 secret_id[UV_SECRET_ID_LEN],
const struct uv_secret_list *list,
struct uv_secret_list_item_hdr *secret)
{
u16 i;
for (i = 0; i < list->total_num_secrets; i++) {
if (memcmp(secret_id, list->secrets[i].id, UV_SECRET_ID_LEN) == 0) {
*secret = list->secrets[i].hdr;
return 0;
}
}
return -ENOENT;
}
/*
* Do the actual search for `uv_get_secret_metadata`.
*
* Context: might sleep.
*/
static int find_secret(const u8 secret_id[UV_SECRET_ID_LEN],
struct uv_secret_list *list,
struct uv_secret_list_item_hdr *secret)
{
u16 start_idx = 0;
u16 list_rc;
int ret;
do {
uv_list_secrets(list, start_idx, &list_rc, NULL);
if (list_rc != UVC_RC_EXECUTED && list_rc != UVC_RC_MORE_DATA) {
if (list_rc == UVC_RC_INV_CMD)
return -ENODEV;
else
return -EIO;
}
ret = find_secret_in_page(secret_id, list, secret);
if (ret == 0)
return ret;
start_idx = list->next_secret_idx;
} while (list_rc == UVC_RC_MORE_DATA && start_idx < list->next_secret_idx);
return -ENOENT;
}
/**
* uv_get_secret_metadata() - get secret metadata for a given secret id.
* @secret_id: search pattern.
* @secret: output data, containing the secret's metadata.
*
* Search for a secret with the given secret_id in the Ultravisor secret store.
*
* Context: might sleep.
*
* Return:
* * %0: - Found entry; secret->idx and secret->type are valid.
* * %ENOENT - No entry found.
* * %ENODEV: - Not supported: UV not available or command not available.
* * %EIO: - Other unexpected UV error.
*/
int uv_get_secret_metadata(const u8 secret_id[UV_SECRET_ID_LEN],
struct uv_secret_list_item_hdr *secret)
{
struct uv_secret_list *buf;
int rc;
buf = kzalloc(sizeof(*buf), GFP_KERNEL);
if (!buf)
return -ENOMEM;
rc = find_secret(secret_id, buf, secret);
kfree(buf);
return rc;
}
EXPORT_SYMBOL_GPL(uv_get_secret_metadata);
/**
* uv_retrieve_secret() - get the secret value for the secret index.
* @secret_idx: Secret index for which the secret should be retrieved.
* @buf: Buffer to store retrieved secret.
* @buf_size: Size of the buffer. The correct buffer size is reported as part of
* the result from `uv_get_secret_metadata`.
*
* Calls the Retrieve Secret UVC and translates the UV return code into an errno.
*
* Context: might sleep.
*
* Return:
* * %0 - Entry found; buffer contains a valid secret.
* * %ENOENT: - No entry found or secret at the index is non-retrievable.
* * %ENODEV: - Not supported: UV not available or command not available.
* * %EINVAL: - Buffer too small for content.
* * %EIO: - Other unexpected UV error.
*/
int uv_retrieve_secret(u16 secret_idx, u8 *buf, size_t buf_size)
{
struct uv_cb_retr_secr uvcb = {
.header.len = sizeof(uvcb),
.header.cmd = UVC_CMD_RETR_SECRET,
.secret_idx = secret_idx,
.buf_addr = (u64)buf,
.buf_size = buf_size,
};
uv_call_sched(0, (u64)&uvcb);
switch (uvcb.header.rc) {
case UVC_RC_EXECUTED:
return 0;
case UVC_RC_INV_CMD:
return -ENODEV;
case UVC_RC_RETR_SECR_STORE_EMPTY:
case UVC_RC_RETR_SECR_INV_SECRET:
case UVC_RC_RETR_SECR_INV_IDX:
return -ENOENT;
case UVC_RC_RETR_SECR_BUF_SMALL:
return -EINVAL;
default:
return -EIO;
}
}
EXPORT_SYMBOL_GPL(uv_retrieve_secret);