From 1038fd78a1b8269b642ce09600242682186a78e2 Mon Sep 17 00:00:00 2001 From: Nicolai Stange Date: Mon, 21 Feb 2022 13:10:47 +0100 Subject: crypto: kpp - provide support for KPP template instances The upcoming support for the RFC 7919 ffdhe group parameters will be made available in the form of templates like "ffdhe2048(dh)", "ffdhe3072(dh)" and so on. Template instantiations thereof would wrap the inner "dh" kpp_alg and also provide kpp_alg services to the outside again. Furthermore, it might be perhaps be desirable to provide KDF templates in the future, which would similarly wrap an inner kpp_alg and present themselves to the outside as another kpp_alg, transforming the shared secret on its way out. Introduce the bits needed for supporting KPP template instances. Everything related to inner kpp_alg spawns potentially being held by such template instances will be deferred to a subsequent patch in order to facilitate review. Define struct struct kpp_instance in close analogy to the already existing skcipher_instance, shash_instance and alike, but wrapping a struct kpp_alg. Implement the new kpp_register_instance() template instance registration primitive. Provide some helper functions for - going back and forth between a generic struct crypto_instance and the new struct kpp_instance, - obtaining the instantiating kpp_instance from a crypto_kpp transform and - for accessing a given kpp_instance's implementation specific context data. Annotate everything with proper kernel-doc comments, even though include/crypto/internal/kpp.h is not considered for the generated docs. Signed-off-by: Nicolai Stange Reviewed-by: Hannes Reinecke Signed-off-by: Herbert Xu --- include/crypto/internal/kpp.h | 83 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) (limited to 'include/crypto/internal') diff --git a/include/crypto/internal/kpp.h b/include/crypto/internal/kpp.h index 659b642efada..c4d5a970fe9d 100644 --- a/include/crypto/internal/kpp.h +++ b/include/crypto/internal/kpp.h @@ -10,6 +10,24 @@ #include #include +/** + * struct kpp_instance - KPP template instance + * @free: Callback getting invoked upon instance destruction. Must be set. + * @s: Internal. Generic crypto core instance state properly layout + * to alias with @alg as needed. + * @alg: The &struct kpp_alg implementation provided by the instance. + */ +struct kpp_instance { + void (*free)(struct kpp_instance *inst); + union { + struct { + char head[offsetof(struct kpp_alg, base)]; + struct crypto_instance base; + } s; + struct kpp_alg alg; + }; +}; + /* * Transform internal helpers. */ @@ -33,6 +51,62 @@ static inline const char *kpp_alg_name(struct crypto_kpp *tfm) return crypto_kpp_tfm(tfm)->__crt_alg->cra_name; } +/* + * Template instance internal helpers. + */ +/** + * kpp_crypto_instance() - Cast a &struct kpp_instance to the corresponding + * generic &struct crypto_instance. + * @inst: Pointer to the &struct kpp_instance to be cast. + * Return: A pointer to the &struct crypto_instance embedded in @inst. + */ +static inline struct crypto_instance *kpp_crypto_instance( + struct kpp_instance *inst) +{ + return &inst->s.base; +} + +/** + * kpp_instance() - Cast a generic &struct crypto_instance to the corresponding + * &struct kpp_instance. + * @inst: Pointer to the &struct crypto_instance to be cast. + * Return: A pointer to the &struct kpp_instance @inst is embedded in. + */ +static inline struct kpp_instance *kpp_instance(struct crypto_instance *inst) +{ + return container_of(inst, struct kpp_instance, s.base); +} + +/** + * kpp_alg_instance() - Get the &struct kpp_instance a given KPP transform has + * been instantiated from. + * @kpp: The KPP transform instantiated from some &struct kpp_instance. + * Return: The &struct kpp_instance associated with @kpp. + */ +static inline struct kpp_instance *kpp_alg_instance(struct crypto_kpp *kpp) +{ + return kpp_instance(crypto_tfm_alg_instance(&kpp->base)); +} + +/** + * kpp_instance_ctx() - Get a pointer to a &struct kpp_instance's implementation + * specific context data. + * @inst: The &struct kpp_instance whose context data to access. + * + * A KPP template implementation may allocate extra memory beyond the + * end of a &struct kpp_instance instantiated from &crypto_template.create(). + * This function provides a means to obtain a pointer to this area. + * + * Return: A pointer to the implementation specific context data. + */ +static inline void *kpp_instance_ctx(struct kpp_instance *inst) +{ + return crypto_instance_ctx(kpp_crypto_instance(inst)); +} + +/* + * KPP algorithm (un)registration functions. + */ /** * crypto_register_kpp() -- Register key-agreement protocol primitives algorithm * @@ -56,4 +130,13 @@ int crypto_register_kpp(struct kpp_alg *alg); */ void crypto_unregister_kpp(struct kpp_alg *alg); +/** + * kpp_register_instance() - Register a KPP template instance. + * @tmpl: The instantiating template. + * @inst: The KPP template instance to be registered. + * Return: %0 on success, negative error code otherwise. + */ +int kpp_register_instance(struct crypto_template *tmpl, + struct kpp_instance *inst); + #endif -- cgit From 46ed5269bf7dac752f78fc5f8dc5efb52b483fe7 Mon Sep 17 00:00:00 2001 From: Nicolai Stange Date: Mon, 21 Feb 2022 13:10:48 +0100 Subject: crypto: kpp - provide support for KPP spawns The upcoming support for the RFC 7919 ffdhe group parameters will be made available in the form of templates like "ffdhe2048(dh)", "ffdhe3072(dh)" and so on. Template instantiations thereof would wrap the inner "dh" kpp_alg and also provide kpp_alg services to the outside again. The primitves needed for providing kpp_alg services from template instances have been introduced with the previous patch. Continue this work now and implement everything needed for enabling template instances to make use of inner KPP algorithms like "dh". More specifically, define a struct crypto_kpp_spawn in close analogy to crypto_skcipher_spawn, crypto_shash_spawn and alike. Implement a crypto_grab_kpp() and crypto_drop_kpp() pair for binding such a spawn to some inner kpp_alg and for releasing it respectively. Template implementations can instantiate transforms from the underlying kpp_alg by means of the new crypto_spawn_kpp(). Finally, provide the crypto_spawn_kpp_alg() helper for accessing a spawn's underlying kpp_alg during template instantiation. Annotate everything with proper kernel-doc comments, even though include/crypto/internal/kpp.h is not considered for the generated docs. Signed-off-by: Nicolai Stange Reviewed-by: Hannes Reinecke Signed-off-by: Herbert Xu --- include/crypto/internal/kpp.h | 75 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) (limited to 'include/crypto/internal') diff --git a/include/crypto/internal/kpp.h b/include/crypto/internal/kpp.h index c4d5a970fe9d..9cb0662ebe87 100644 --- a/include/crypto/internal/kpp.h +++ b/include/crypto/internal/kpp.h @@ -28,6 +28,20 @@ struct kpp_instance { }; }; +/** + * struct crypto_kpp_spawn - KPP algorithm spawn + * @base: Internal. Generic crypto core spawn state. + * + * Template instances can get a hold on some inner KPP algorithm by + * binding a &struct crypto_kpp_spawn via + * crypto_grab_kpp(). Transforms may subsequently get instantiated + * from the referenced inner &struct kpp_alg by means of + * crypto_spawn_kpp(). + */ +struct crypto_kpp_spawn { + struct crypto_spawn base; +}; + /* * Transform internal helpers. */ @@ -139,4 +153,65 @@ void crypto_unregister_kpp(struct kpp_alg *alg); int kpp_register_instance(struct crypto_template *tmpl, struct kpp_instance *inst); +/* + * KPP spawn related functions. + */ +/** + * crypto_grab_kpp() - Look up a KPP algorithm and bind a spawn to it. + * @spawn: The KPP spawn to bind. + * @inst: The template instance owning @spawn. + * @name: The KPP algorithm name to look up. + * @type: The type bitset to pass on to the lookup. + * @mask: The mask bismask to pass on to the lookup. + * Return: %0 on success, a negative error code otherwise. + */ +int crypto_grab_kpp(struct crypto_kpp_spawn *spawn, + struct crypto_instance *inst, + const char *name, u32 type, u32 mask); + +/** + * crypto_drop_kpp() - Release a spawn previously bound via crypto_grab_kpp(). + * @spawn: The spawn to release. + */ +static inline void crypto_drop_kpp(struct crypto_kpp_spawn *spawn) +{ + crypto_drop_spawn(&spawn->base); +} + +/** + * crypto_spawn_kpp_alg() - Get the algorithm a KPP spawn has been bound to. + * @spawn: The spawn to get the referenced &struct kpp_alg for. + * + * This function as well as the returned result are safe to use only + * after @spawn has been successfully bound via crypto_grab_kpp() and + * up to until the template instance owning @spawn has either been + * registered successfully or the spawn has been released again via + * crypto_drop_spawn(). + * + * Return: A pointer to the &struct kpp_alg referenced from the spawn. + */ +static inline struct kpp_alg *crypto_spawn_kpp_alg( + struct crypto_kpp_spawn *spawn) +{ + return container_of(spawn->base.alg, struct kpp_alg, base); +} + +/** + * crypto_spawn_kpp() - Create a transform from a KPP spawn. + * @spawn: The spawn previously bound to some &struct kpp_alg via + * crypto_grab_kpp(). + * + * Once a &struct crypto_kpp_spawn has been successfully bound to a + * &struct kpp_alg via crypto_grab_kpp(), transforms for the latter + * may get instantiated from the former by means of this function. + * + * Return: A pointer to the freshly created KPP transform on success + * or an ``ERR_PTR()`` otherwise. + */ +static inline struct crypto_kpp *crypto_spawn_kpp( + struct crypto_kpp_spawn *spawn) +{ + return crypto_spawn_tfm2(&spawn->base); +} + #endif -- cgit