diff options
| -rw-r--r-- | crypto/dh.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/crypto/dh.c b/crypto/dh.c index abc2a72c8271..08fb7610fe2a 100644 --- a/crypto/dh.c +++ b/crypto/dh.c @@ -257,6 +257,214 @@ static struct kpp_alg dh = { }, }; + +struct dh_safe_prime { + unsigned int max_strength; + unsigned int p_size; + const char *p; +}; + +static const char safe_prime_g[] = { 2 }; + +struct dh_safe_prime_instance_ctx { + struct crypto_kpp_spawn dh_spawn; + const struct dh_safe_prime *safe_prime; +}; + +struct dh_safe_prime_tfm_ctx { + struct crypto_kpp *dh_tfm; +}; + +static void dh_safe_prime_free_instance(struct kpp_instance *inst) +{ + struct dh_safe_prime_instance_ctx *ctx = kpp_instance_ctx(inst); + + crypto_drop_kpp(&ctx->dh_spawn); + kfree(inst); +} + +static inline struct dh_safe_prime_instance_ctx *dh_safe_prime_instance_ctx( + struct crypto_kpp *tfm) +{ + return kpp_instance_ctx(kpp_alg_instance(tfm)); +} + +static inline struct kpp_alg *dh_safe_prime_dh_alg( + struct dh_safe_prime_tfm_ctx *ctx) +{ + return crypto_kpp_alg(ctx->dh_tfm); +} + +static int dh_safe_prime_init_tfm(struct crypto_kpp *tfm) +{ + struct dh_safe_prime_instance_ctx *inst_ctx = + dh_safe_prime_instance_ctx(tfm); + struct dh_safe_prime_tfm_ctx *tfm_ctx = kpp_tfm_ctx(tfm); + + tfm_ctx->dh_tfm = crypto_spawn_kpp(&inst_ctx->dh_spawn); + if (IS_ERR(tfm_ctx->dh_tfm)) + return PTR_ERR(tfm_ctx->dh_tfm); + + return 0; +} + +static void dh_safe_prime_exit_tfm(struct crypto_kpp *tfm) +{ + struct dh_safe_prime_tfm_ctx *tfm_ctx = kpp_tfm_ctx(tfm); + + crypto_free_kpp(tfm_ctx->dh_tfm); +} + +static int dh_safe_prime_set_secret(struct crypto_kpp *tfm, const void *buffer, + unsigned int len) +{ + struct dh_safe_prime_instance_ctx *inst_ctx = + dh_safe_prime_instance_ctx(tfm); + struct dh_safe_prime_tfm_ctx *tfm_ctx = kpp_tfm_ctx(tfm); + struct dh params; + void *buf; + unsigned int buf_size; + int err; + + err = __crypto_dh_decode_key(buffer, len, ¶ms); + if (err) + return err; + + if (params.p_size || params.g_size) + return -EINVAL; + + params.p = inst_ctx->safe_prime->p; + params.p_size = inst_ctx->safe_prime->p_size; + params.g = safe_prime_g; + params.g_size = sizeof(safe_prime_g); + + buf_size = crypto_dh_key_len(¶ms); + buf = kmalloc(buf_size, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + err = crypto_dh_encode_key(buf, buf_size, ¶ms); + if (err) + goto out; + + err = crypto_kpp_set_secret(tfm_ctx->dh_tfm, buf, buf_size); +out: + kfree_sensitive(buf); + return err; +} + +static void dh_safe_prime_complete_req(struct crypto_async_request *dh_req, + int err) +{ + struct kpp_request *req = dh_req->data; + + kpp_request_complete(req, err); +} + +static struct kpp_request *dh_safe_prime_prepare_dh_req(struct kpp_request *req) +{ + struct dh_safe_prime_tfm_ctx *tfm_ctx = + kpp_tfm_ctx(crypto_kpp_reqtfm(req)); + struct kpp_request *dh_req = kpp_request_ctx(req); + + kpp_request_set_tfm(dh_req, tfm_ctx->dh_tfm); + kpp_request_set_callback(dh_req, req->base.flags, + dh_safe_prime_complete_req, req); + + kpp_request_set_input(dh_req, req->src, req->src_len); + kpp_request_set_output(dh_req, req->dst, req->dst_len); + + return dh_req; +} + +static int dh_safe_prime_generate_public_key(struct kpp_request *req) +{ + struct kpp_request *dh_req = dh_safe_prime_prepare_dh_req(req); + + return crypto_kpp_generate_public_key(dh_req); +} + +static int dh_safe_prime_compute_shared_secret(struct kpp_request *req) +{ + struct kpp_request *dh_req = dh_safe_prime_prepare_dh_req(req); + + return crypto_kpp_compute_shared_secret(dh_req); +} + +static unsigned int dh_safe_prime_max_size(struct crypto_kpp *tfm) +{ + struct dh_safe_prime_tfm_ctx *tfm_ctx = kpp_tfm_ctx(tfm); + + return crypto_kpp_maxsize(tfm_ctx->dh_tfm); +} + +static int __maybe_unused __dh_safe_prime_create( + struct crypto_template *tmpl, struct rtattr **tb, + const struct dh_safe_prime *safe_prime) +{ + struct kpp_instance *inst; + struct dh_safe_prime_instance_ctx *ctx; + const char *dh_name; + struct kpp_alg *dh_alg; + u32 mask; + int err; + + err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_KPP, &mask); + if (err) + return err; + + dh_name = crypto_attr_alg_name(tb[1]); + if (IS_ERR(dh_name)) + return PTR_ERR(dh_name); + + inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); + if (!inst) + return -ENOMEM; + + ctx = kpp_instance_ctx(inst); + + err = crypto_grab_kpp(&ctx->dh_spawn, kpp_crypto_instance(inst), + dh_name, 0, mask); + if (err) + goto err_free_inst; + + err = -EINVAL; + dh_alg = crypto_spawn_kpp_alg(&ctx->dh_spawn); + if (strcmp(dh_alg->base.cra_name, "dh")) + goto err_free_inst; + + ctx->safe_prime = safe_prime; + + err = crypto_inst_setname(kpp_crypto_instance(inst), + tmpl->name, &dh_alg->base); + if (err) + goto err_free_inst; + + inst->alg.set_secret = dh_safe_prime_set_secret; + inst->alg.generate_public_key = dh_safe_prime_generate_public_key; + inst->alg.compute_shared_secret = dh_safe_prime_compute_shared_secret; + inst->alg.max_size = dh_safe_prime_max_size; + inst->alg.init = dh_safe_prime_init_tfm; + inst->alg.exit = dh_safe_prime_exit_tfm; + inst->alg.reqsize = sizeof(struct kpp_request) + dh_alg->reqsize; + inst->alg.base.cra_priority = dh_alg->base.cra_priority; + inst->alg.base.cra_module = THIS_MODULE; + inst->alg.base.cra_ctxsize = sizeof(struct dh_safe_prime_tfm_ctx); + + inst->free = dh_safe_prime_free_instance; + + err = kpp_register_instance(tmpl, inst); + if (err) + goto err_free_inst; + + return 0; + +err_free_inst: + dh_safe_prime_free_instance(inst); + + return err; +} + static int dh_init(void) { return crypto_register_kpp(&dh); |