geniv.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * geniv: Shared IV generator code
  4 *
  5 * This file provides common code to IV generators such as seqiv.
  6 *
  7 * Copyright (c) 2007-2019 Herbert Xu <herbert@gondor.apana.org.au>
  8 */
  9
 10#include <crypto/internal/geniv.h>
 11#include <crypto/internal/rng.h>
 12#include <linux/err.h>
 13#include <linux/kernel.h>
 14#include <linux/module.h>
 15#include <linux/rtnetlink.h>
 16#include <linux/slab.h>
 17
 18static int aead_geniv_setkey(struct crypto_aead *tfm,
 19			     const u8 *key, unsigned int keylen)
 20{
 21	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
 22
 23	return crypto_aead_setkey(ctx->child, key, keylen);
 24}
 25
 26static int aead_geniv_setauthsize(struct crypto_aead *tfm,
 27				  unsigned int authsize)
 28{
 29	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
 30
 31	return crypto_aead_setauthsize(ctx->child, authsize);
 32}
 33
 34static void aead_geniv_free(struct aead_instance *inst)
 35{
 36	crypto_drop_aead(aead_instance_ctx(inst));
 37	kfree(inst);
 38}
 39
 40struct aead_instance *aead_geniv_alloc(struct crypto_template *tmpl,
 41				       struct rtattr **tb)
 42{
 43	struct crypto_aead_spawn *spawn;
 44	struct aead_instance *inst;
 45	struct aead_alg *alg;
 46	unsigned int ivsize;
 47	unsigned int maxauthsize;
 48	u32 mask;
 49	int err;
 50
 51	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
 52	if (err)
 53		return ERR_PTR(err);
 54
 55	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
 56	if (!inst)
 57		return ERR_PTR(-ENOMEM);
 58
 59	spawn = aead_instance_ctx(inst);
 60
 61	err = crypto_grab_aead(spawn, aead_crypto_instance(inst),
 62			       crypto_attr_alg_name(tb[1]), 0, mask);
 63	if (err)
 64		goto err_free_inst;
 65
 66	alg = crypto_spawn_aead_alg(spawn);
 67
 68	ivsize = crypto_aead_alg_ivsize(alg);
 69	maxauthsize = crypto_aead_alg_maxauthsize(alg);
 70
 71	err = -EINVAL;
 72	if (ivsize < sizeof(u64))
 73		goto err_free_inst;
 74
 75	err = -ENAMETOOLONG;
 76	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 77		     "%s(%s)", tmpl->name, alg->base.cra_name) >=
 78	    CRYPTO_MAX_ALG_NAME)
 79		goto err_free_inst;
 80	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 81		     "%s(%s)", tmpl->name, alg->base.cra_driver_name) >=
 82	    CRYPTO_MAX_ALG_NAME)
 83		goto err_free_inst;
 84
 85	inst->alg.base.cra_priority = alg->base.cra_priority;
 86	inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
 87	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
 88	inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
 89
 90	inst->alg.setkey = aead_geniv_setkey;
 91	inst->alg.setauthsize = aead_geniv_setauthsize;
 92
 93	inst->alg.ivsize = ivsize;
 94	inst->alg.maxauthsize = maxauthsize;
 95
 96	inst->free = aead_geniv_free;
 97
 98out:
 99	return inst;
100
101err_free_inst:
102	aead_geniv_free(inst);
103	inst = ERR_PTR(err);
104	goto out;
105}
106EXPORT_SYMBOL_GPL(aead_geniv_alloc);
107
108int aead_init_geniv(struct crypto_aead *aead)
109{
110	struct aead_geniv_ctx *ctx = crypto_aead_ctx(aead);
111	struct aead_instance *inst = aead_alg_instance(aead);
112	struct crypto_aead *child;
113	int err;
114
115	spin_lock_init(&ctx->lock);
116
117	err = crypto_get_default_rng();
118	if (err)
119		goto out;
120
121	err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
122				   crypto_aead_ivsize(aead));
123	crypto_put_default_rng();
124	if (err)
125		goto out;
126
127	child = crypto_spawn_aead(aead_instance_ctx(inst));
128	err = PTR_ERR(child);
129	if (IS_ERR(child))
130		goto out;
131
132	ctx->child = child;
133	crypto_aead_set_reqsize(aead, crypto_aead_reqsize(child) +
134				      sizeof(struct aead_request));
135
136	err = 0;
137
138out:
139	return err;
140}
141EXPORT_SYMBOL_GPL(aead_init_geniv);
142
143void aead_exit_geniv(struct crypto_aead *tfm)
144{
145	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
146
147	crypto_free_aead(ctx->child);
148}
149EXPORT_SYMBOL_GPL(aead_exit_geniv);
150
151MODULE_LICENSE("GPL");
152MODULE_DESCRIPTION("Shared IV generator code");