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@xxxxxxxxxxxxx> Signed-off-by: Steffen Eiden <seiden@xxxxxxxxxxxxx> --- Resend this patch rebased onto my other series 's390/uv: Provide host-key hashes in sysfs' see: https://lore.kernel.org/lkml/20241015113940.3088249-1-seiden@xxxxxxxxxxxxx/ arch/s390/include/asm/uv.h | 136 ++++++++++++++++++++++++++++++++++++- arch/s390/kernel/uv.c | 129 ++++++++++++++++++++++++++++++++++- 2 files changed, 262 insertions(+), 3 deletions(-) diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h index 49ca54827379..729b1e057784 100644 --- a/arch/s390/include/asm/uv.h +++ b/arch/s390/include/asm/uv.h @@ -2,7 +2,7 @@ /* * Ultravisor Interfaces * - * Copyright IBM Corp. 2019, 2022 + * Copyright IBM Corp. 2019, 2024 * * Author(s): * Vasily Gorbik <gor@xxxxxxxxxxxxx> @@ -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) diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c index 3c74e6179cdc..4fbe63f59ebd 100644 --- a/arch/s390/kernel/uv.c +++ b/arch/s390/kernel/uv.c @@ -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); -- 2.45.2
