Files
s390-tools/zkey/kms-plugin.h
Ingo Franzki 154914ee7a zkey: Allow KMS plugin to import a key of a specific type
KMS plugins that support multiple key types need to know which
key type to produce with the kms_import_key() function. Extend
the plugin API to allow a plugin to provide a kms_import_key2()
function, that accepts the key type as additional parameter.

Existing plugins do not need to be changed, as the old function
kms_import_key() still exists, and is still used when the plugin
does not provide a kms_import_key2() function.

Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
2021-07-07 13:53:06 +02:00

576 lines
25 KiB
C

/*
* zkey - Generate, re-encipher, and validate secure keys
*
* This header file defines the interface to a Key Management System (KMS)
* Plugin.
*
* Copyright IBM Corp. 2020
*
* s390-tools is free software; you can redistribute it and/or modify
* it under the terms of the MIT license. See LICENSE for details.
*/
#ifndef KMS_PLUGIN_H
#define KMS_PLUGIN_H
#include <stddef.h>
#include <stdbool.h>
#include "lib/util_opt.h"
/**
* Informs a KMS plugin that it is bound to a zkey repository.
*
* Note: This function is called before kms_initialize()!
*
* @param config_path name of a directory where the KMS plugin can store
* its configuration and other files it needs to store
*
* @returns 0 on success, or a negative errno in case of an error.
*/
int kms_bind(const char *config_path);
typedef void *kms_handle_t;
/**
* Initializes a KMS plugin for usage by zkey. When a repository is bound to a
* KMS plugin, zkey calls this function when opening the repository.
*
* @param config_path name of a directory where the KMS plugin can store
* its configuration and other files it needs to store
* @param verbose if true, the plugin should write verbose or debug
* messages to stderr during further processing.
*
* @returns a KMS plugin handle, or NULL in case of an error.
*/
kms_handle_t kms_initialize(const char *config_path, bool verbose);
/**
* Terminates the use of a KMS plugin. When a repository is bound to a KMS
* plugin, zkey calls this function when closing the repository.
*
* @param handle the KMS plugin handle obtained from kms_initialize()
*
* @returns 0 on success, or a negative errno in case of an error.
* Function kms_get_last_error() can be used to obtain more details about the
* error.
*/
int kms_terminate(const kms_handle_t handle);
/**
* Returns a textual message about the last occurred error that occurred in the
* last called KMS plugin function. If no error occurred (i.e. the last plugin
* function returned rc = 0), then NULL is returned.
* The returned string is static or contained within the handle. It is valid
* only until the next KMS plugin function is called.
*
* @param handle the KMS plugin handle obtained from kms_initialize()
*
* @returns an error message of NULL
*/
const char *kms_get_last_error(const kms_handle_t handle);
/**
* Returns true if the KMS plugin supports the specified key type.
*
* @param handle the KMS plugin handle obtained from kms_initialize()
* @param key_type the zkey key type, euch as 'CCA-AESDATA',
* 'CCA-AESCIPHER', 'EP11-AES'.
*
* @returns true if the KMS plugin supports the key type, false otherwise.
*/
bool kms_supports_key_type(const kms_handle_t handle, const char *key_type);
/**
* Displays information about the KMS Plugin and its current configuration on
* stdout.
*
* @param handle the KMS plugin handle obtained from kms_initialize()
*
* @returns 0 on success, or a negative errno in case of an error.
* Function kms_get_last_error() can be used to obtain more details about the
* error.
*/
int kms_display_info(const kms_handle_t handle);
#define KMS_COMMAND_CONFIGURE "configure"
#define KMS_COMMAND_REENCIPHER "reencipher"
#define KMS_COMMAND_GENERATE "generate"
#define KMS_COMMAND_REMOVE "remove"
#define KMS_COMMAND_LIST "list"
#define KMS_COMMAND_LIST_IMPORT "list-import"
/**
* Returns a list of KMS specific command line options that zkey should accept
* and pass to the appropriate KMS plugin function. The option list must be
* terminated by an UTIL_OPT_END entry (see util_opt.h). The options returned
* must not interfere with the already defined options of the zkey command.
* Field 'command' of the returned options should either be NULL or specify
* the command that it is for.
*
* If max_opts is not -1, then only up to max_opts options are allowed. If more
* options are returned, only up to max_opts options are used by zkey.
*
* @param command the command for which the KMS-specific options are
* to be returned, see KMS_COMMAND_xxx defines
* @param max_opts maximum number of options allowed. If -1 then there
* is no limit.
*
* @returns a list of options terminated by an UTIL_OPT_END entry, or NULL in
* case of an error.
* Function kms_get_last_error() can be used to obtain more details about the
* error.
*/
const struct util_opt *kms_get_command_options(const char *command,
int max_opts);
struct kms_apqn {
unsigned short card;
unsigned short domain;
};
struct kms_option {
int option; /** option character as in struct option */
const char *argument; /** argument of the option (if any) */
};
/**
* Configures (or re-configures) a KMS plugin. This function can be called
* several times to configure a KMS plugin is several steps (if supported by the
* KMS plugin). In case a configuration is not fully complete, this function
* may return -EAGAIN to indicate that it has accepted the configuration so far,
* but the configuration needs to be completed.
*
* No kms_login is performed before calling this function. If the KMS plugin
* requires a login for the configuration, it must perform it itself within this
* function.
*
* A KMS plugin must be associated with at least one APQN. Thus, in a multi-step
* configuration, a list f APQNs must be specified at least once.
*
* @param handle the KMS plugin handle obtained from kms_initialize()
* @param apqns a list of APQNs to associate with the KMS plugin, or
* NULL if no APQNs are specified.
* @param num_apqns number of APQNs in above array. 0 if no APQNs are
* specified.
* @param options a list of options as specified by the user. These
* options are a subset of the possible options as
* returned by kms_get_command_options() with command
* KMS_COMMAND_CONFIGURE.
* @param num_options number of options in above array.
*
* @returns 0 on success, or a negative errno in case of an error.
* Function kms_get_last_error() can be used to obtain more details about the
* error.
* -EAGAIN to indicate that the specified configuration was accepted so far, but
* the configuration is still incomplete, and needs to be completed.
*/
int kms_configure(const kms_handle_t handle,
const struct kms_apqn *apqns, size_t num_apqns,
const struct kms_option *options, size_t num_options);
/**
* De-configures a KMS plugin. This is called by zkey when a repository is
* unbound from a KMS plugin. It gives the KMS plugin the chance to gracefully
* remove any files that the plugin has stored in its config directory. zkey
* will unconditionally remove all left over files when this function returns.
*
* @param handle the KMS plugin handle obtained from kms_initialize()
*
* @returns 0 on success, or a negative errno in case of an error.
* Function kms_get_last_error() can be used to obtain more details about the
* error.
*/
int kms_deconfigure(const kms_handle_t handle);
/**
* Allows the KMS plugin to perform a login to the KMS (if required). This
* function is called at least once before any key operation function, typically
* shortly after opening the repository.
* The KMS plugin may prompt the user (by reading from stdin) for its
* credentials, if needed.
*
* It is suggested that a KMS plugin performs a login with the KMS once, and
* stores a login token (or similar) in its config directory. The next time
* the kms_login function is called, the login token can be reused (if still
* valid). This avoids to prompt the user for every key operation.
*
* @param handle the KMS plugin handle obtained from kms_initialize()
*
* @returns 0 on success, or a negative errno in case of an error.
* Function kms_get_last_error() can be used to obtain more details about the
* error.
*/
int kms_login(const kms_handle_t handle);
enum kms_reencipher_mode {
KMS_REENC_MODE_AUTO = 0,
KMS_REENC_MODE_IN_PLACE = 1,
KMS_REENC_MODE_STAGED = 2,
KMS_REENC_MODE_STAGED_COMPLETE = 3,
};
enum kms_reenc_mkreg {
KMS_REENC_MKREG_AUTO = 0,
KMS_REENC_MKREG_FROM_OLD = 1,
KMS_REENC_MKREG_TO_NEW = 2,
KMS_REENC_MKREG_FROM_OLD_TO_NEW = 3,
};
/**
* Called when the master keys of an APQN associated with the KMS plugin has
* been changed. The KMS plugin can then re-encipher all its secure keys (if
* any) that it has stored in its config directory.
*
* Keys that have been generated by the KMS plugin and stored in the zkey
* repository do not need to be re-enciphered by the KMS plugin. Those are
* re-enciphered by zkey without the help of the KMS plugin.
*
* HSM have different master key registers. Typically a CURRENT and a NEW master
* key register exists. The NEW register may be loaded with the new to be set
* master key, and secure keys can be re-enciphered with it proactively.
*
* CCA also supports an OLD master key register, that contains the previously
* used master key. You thus can re-encipher a secure key that is currently
* enciphered with the master key from the OLD register with the master key
* from the CURRENT register.
*
* HSMs may also support different master keys for different key types or
* algorithms. It is up to the KMS plugin to know which master key registers
* are used for its secure keys
*
* A staged re-encipherment is performed by re-enciphering a secure key with
* the new HSM master key, without making it available for use in the first
* stage. Only when the staged re-encipherment is completed, then the previously
* re-enciphered secure key is make available for use and the old on is removed.
*
* An in-place re-encipherment replaces the secure key right away with its
* re-enciphered version.
*
* @param handle the KMS plugin handle obtained from kms_initialize()
* @param mode Re-encipherment mode
* @param mkreg Re-encipherment register selection
* @param options a list of options as specified by the user. These
* options are a subset of the possible options as
* returned by kms_get_command_options() with command
* KMS_COMMAND_REENCIPHER.
* @param num_options number of options in above array.
*
* @returns 0 on success, or a negative errno in case of an error.
* Function kms_get_last_error() can be used to obtain more details about the
* error.
*/
int kms_reenciper(const kms_handle_t handle,
enum kms_reencipher_mode mode, enum kms_reenc_mkreg mkreg,
const struct kms_option *options, size_t num_options);
struct kms_property {
const char *name;
const char *value;
};
#define KMS_KEY_ID_SIZE 256
#define KMS_KEY_LABEL_SIZE 256
enum kms_key_mode {
KMS_KEY_MODE_NON_XTS = 0,
KMS_KEY_MODE_XTS_1 = 1,
KMS_KEY_MODE_XTS_2 = 2,
};
/**
* Generates a key in or with the KMS and returns a secure key that is
* enciphered under the current HSM master key.
*
* @param handle the KMS plugin handle obtained from kms_initialize()
* @param key_type the zkey key type, euch as 'CCA-AESDATA',
* 'CCA-AESCIPHER', 'EP11-AES'.
* @param key_bits the key bit size (e.g. 256 for an AES 256 bit key).
* 0 to use the plugin's default key size.
* @param key_mode mode of the key, e.g. non-XTS key, or first/second
* XTS key to be generated. A KMS plugin may need to
* use different key templates for the different key
* modes (i.e. key parts).
* @param properties a list of properties to associate the key with
* @param num_properties the number of properties in above array
* @param options a list of options as specified by the user. These
* options are a subset of the possible options as
* returned by kms_get_command_options() with command
* KMS_COMMAND_GENERATE.
* @param num_options number of options in above array.
* @param key_blob a buffer to return the key blob. The size of the
* buffer is specified in key_blob_length
* @param key_blob_length on entry: the size of the key_blob buffer.
* on exit: the size of the key blob returned.
* @param key_id a buffer to return the key-ID of the generated key.
* The key-id is a textual identifier uniquely
* identifying a key in the KMS and the KMS plugin.
* The returned key-id contains the terminating zero.
* @paran key_id_size size of the key_id buffer. It should be at least
* KMS_KEY_ID_SIZE + 1 bytes large.
* @param key_label a buffer to return the key-label of the generated
* key. The key-label is a textual identifier used to
* identify a key in the user interface of the KMS.
* A key label may be equal to the key-ID, or it may
* different. The returned key-label contains the
* terminating zero.
* @paran key_label_size size of the key_lanble buffer. It should be at least
* KMS_KEY_LABEL_SIZE + 1 bytes large.
*
* @returns 0 on success, or a negative errno in case of an error.
* Function kms_get_last_error() can be used to obtain more details about the
* error.
*/
int kms_generate_key(const kms_handle_t handle, const char *key_type,
size_t key_bits, enum kms_key_mode key_mode,
const struct kms_property *properties,
size_t num_properties, const struct kms_option *options,
size_t num_options, unsigned char *key_blob,
size_t *key_blob_length, char *key_id,
size_t key_id_size, char *key_label,
size_t key_label_size);
/**
* Sets (adds/replaces/removes) properties of a key. Already existing properties
* with the same property name are replaced, non-existing properties are added.
* To remove a property, set the property value to NULL.
*
* @param handle the KMS plugin handle obtained from kms_initialize()
* @param key_id the key-ID to set the properties for
* @param properties a list of properties to set
* @param num_properties the number of properties in above array
*
* @returns 0 on success, or a negative errno in case of an error.
* Function kms_get_last_error() can be used to obtain more details about the
* error.
*/
int kms_set_key_properties(const kms_handle_t handle, const char *key_id,
const struct kms_property *properties,
size_t num_properties);
/**
* Gets properties of a key.
*
* The returned list of properties must be freed by the caller. Each property
* name and value must be freed individually (using free()), as well as the
* complete array.
*
* @param handle the KMS plugin handle obtained from kms_initialize()
* @param key_id the key-ID to set the properties for
* @param properties On return: a list of properties
* @param num_properties On return: the number of properties in above array
*
* @returns 0 on success, or a negative errno in case of an error.
* Function kms_get_last_error() can be used to obtain more details about the
* error.
*/
int kms_get_key_properties(const kms_handle_t handle, const char *key_id,
struct kms_property **properties,
size_t *num_properties);
/**
* Called when zkey removes a KMS-bound key from the zkey repository. The KMS
* plugin can then set the state of the key in the KMS, or remove it also from
* the KMS (this is usually not done).
*
* @param handle the KMS plugin handle obtained from kms_initialize()
* @param key_id the key-ID to set the properties for
* @param options a list of options as specified by the user. These
* options are a subset of the possible options as
* returned by kms_get_command_options() with command
* KMS_COMMAND_REMOVE.
* @param num_options number of options in above array.
*
* @returns 0 on success, or a negative errno in case of an error.
* Function kms_get_last_error() can be used to obtain more details about the
* error.
*/
int kms_remove_key(const kms_handle_t handle, const char *key_id,
const struct kms_option *options, size_t num_options);
/**
* Callback used with the kms_list_keys() function. Called for each key.
*
* @param key_id the key-ID of the key
* @param label the label of the key.
* @param key_type the type of the key (CCA-AESDATA, etc)
* @param key_bits the key size in bits
* @param properties a list of properties of the key
* @param num_properties the number of properties in above array
* @param addl_info_argz an argz string containing additional KMS plugin
* specific infos to be displayed, or NULL if none.
* @param addl_info_len length of the argz string in addl_info_argz
* @param private_data the private data pointer
*
* @returns 0 on success, or a negative errno in case of an error.
*/
typedef int (*kms_list_callback)(const char *key_id, const char *label,
const char *key_type, size_t key_bits,
const struct kms_property *properties,
size_t num_properties,
const char *addl_info_argz,
size_t addl_info_len, void *private_data);
/**
* List keys managed by the KMS. This list is independent of the zkey key
* repository. It lists keys as known by the KMS.
*
* Note: The list function is used to display a list of keys managed by the KMS,
* but also for producing a list of keys to import. Because the two use cases
* might require different plugin specific options, kms_get_command_options()
* allows two commands to get options for:
* - KMS_COMMAND_LIST: Options for displaying a list.
* - KMS_COMMAND_LIST_IMPORT: Options for building a list to import keys.
* Functionkms_list_keys() is called for both cases with the appropriate
* options as returned by kms_get_command_options() for the case.
*
* @param handle the KMS plugin handle obtained from kms_initialize()
* @param label_pattern a pattern of the label used to filter the keys, or
* NULL if no label pattern is specified.
* @param properties a list of properties used to to filter the keys, or
* NULL if no properties filter is specified.
* @param num_properties the number of properties in above array.
* @param options a list of options as specified by the user. These
* options are a subset of the possible options as
* returned by kms_get_command_options() with command
* KMS_COMMAND_LIST or KMS_COMMAND_LIST_IMPORT.
* @param num_options number of options in above array.*
* @param callback a callback function that is called for each key that
* matches the filter (if any).
* @private_data a private pointer passed as is to the callback
* function. Can be used to pass user specific
* information to the callback.
*
* @returns 0 on success, or a negative errno in case of an error.
* Function kms_get_last_error() can be used to obtain more details about the
* error.
*/
int kms_list_keys(const kms_handle_t handle, const char *label_pattern,
const struct kms_property *properties, size_t num_properties,
const struct kms_option *options, size_t num_options,
kms_list_callback callback, void *private_data);
/**
* Imports a key from the KMS and returns a secure key that is
* enciphered under the current HSM master key.
*
* Note: This function is used for an API version 1 plugin. See function
* kms_import_key2 for the version 2 equivalent.
*
* @param handle the KMS plugin handle obtained from kms_initialize()
* @param key_id the key-ID of the key to import
* @param key_blob a buffer to return the key blob. The size of the
* buffer is specified in key_blob_length
* @param key_blob_length on entry: the size of the key_blob buffer.
* on exit: the size of the key blob returned.
*
* @returns 0 on success, or a negative errno in case of an error.
* Function kms_get_last_error() can be used to obtain more details about the
* error.
*/
int kms_import_key(const kms_handle_t handle, const char *key_id,
unsigned char *key_blob, size_t *key_blob_length);
/**
* Imports a key from the KMS and returns a secure key that is
* enciphered under the current HSM master key.
*
* Note: This function should be available for an API version 2 plugin.
* The difference to functionkms_import_key is that it also get the
* desired key type of the key to import.
*
* @param handle the KMS plugin handle obtained from kms_initialize()
* @param key_id the key-ID of the key to import
* @param key_type the zkey key type, such as 'CCA-AESDATA',
* 'CCA-AESCIPHER', 'EP11-AES'. If NULL, then the
* plugin can choose its own default.
* @param key_blob a buffer to return the key blob. The size of the
* buffer is specified in key_blob_length
* @param key_blob_length on entry: the size of the key_blob buffer.
* on exit: the size of the key blob returned.
*
* @returns 0 on success, or a negative errno in case of an error.
* Function kms_get_last_error() can be used to obtain more details about the
* error.
*
*/
int kms_import_key2(const kms_handle_t handle, const char *key_id,
const char *key_type,
unsigned char *key_blob, size_t *key_blob_length);
#define KMS_API_VERSION_1 1
#define KMS_API_VERSION_2 2
struct kms_functions {
unsigned int api_version;
int (*kms_bind)(const char *config_path);
kms_handle_t (*kms_initialize)(const char *config_path, bool verbose);
int (*kms_terminate)(const kms_handle_t handle);
const char *(*kms_get_last_error)(const kms_handle_t handle);
bool (*kms_supports_key_type)(const kms_handle_t handle,
const char *key_type);
int (*kms_display_info)(const kms_handle_t handle);
const struct util_opt *(*kms_get_command_options)(
const char *command, int max_opts);
int (*kms_configure)(const kms_handle_t handle,
const struct kms_apqn *apqns, size_t num_apqns,
const struct kms_option *options,
size_t num_options);
int (*kms_deconfigure)(const kms_handle_t handle);
int (*kms_login)(const kms_handle_t handle);
int (*kms_reenciper)(const kms_handle_t handle,
enum kms_reencipher_mode mode,
enum kms_reenc_mkreg mkreg,
const struct kms_option *options,
size_t num_options);
int (*kms_generate_key)(const kms_handle_t handle,
const char *key_type, size_t key_bits,
enum kms_key_mode key_mode,
const struct kms_property *properties,
size_t num_properties,
const struct kms_option *options,
size_t num_options,
unsigned char *key_blob,
size_t *key_blob_length, char *key_id,
size_t key_id_size, char *key_label,
size_t key_label_size);
int (*kms_set_key_properties)(const kms_handle_t handle,
const char *key_id,
const struct kms_property *properties,
size_t num_properties);
int (*kms_get_key_properties)(const kms_handle_t handle,
const char *key_id,
struct kms_property **properties,
size_t *num_properties);
int (*kms_remove_key)(const kms_handle_t handle, const char *key_id,
const struct kms_option *options,
size_t num_options);
int (*kms_list_keys)(const kms_handle_t handle,
const char *label_pattern,
const struct kms_property *properties,
size_t num_properties,
const struct kms_option *options,
size_t num_options,
kms_list_callback callback, void *private_data);
int (*kms_import_key)(const kms_handle_t handle, const char *key_id,
unsigned char *key_blob,
size_t *key_blob_length);
/* Version 2 functions. Only used when api_version is >= 2. */
int (*kms_import_key2)(const kms_handle_t handle, const char *key_id,
const char *key_type,
unsigned char *key_blob,
size_t *key_blob_length);
};
/**
* Returns an address of a structure containing the KMS plugin functions.
* This function is exported by the KMS plugin, and its address is obtain
* via dlsym() after loading the plugin via dlopen().
* *
* @returns the address of a structure or NULL in case of an error.
*/
const struct kms_functions *kms_get_functions(void);
#endif