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 <crypto/null.h>
13#include <linux/err.h>
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/rtnetlink.h>
17#include <linux/slab.h>
18
19static int aead_geniv_setkey(struct crypto_aead *tfm,
20			     const u8 *key, unsigned int keylen)
21{
22	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
23
24	return crypto_aead_setkey(ctx->child, key, keylen);
25}
26
27static int aead_geniv_setauthsize(struct crypto_aead *tfm,
28				  unsigned int authsize)
29{
30	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
31
32	return crypto_aead_setauthsize(ctx->child, authsize);
33}
34
35static void aead_geniv_free(struct aead_instance *inst)
36{
37	crypto_drop_aead(aead_instance_ctx(inst));
38	kfree(inst);
39}
40
41struct aead_instance *aead_geniv_alloc(struct crypto_template *tmpl,
42				       struct rtattr **tb)
43{
44	struct crypto_aead_spawn *spawn;
45	struct aead_instance *inst;
46	struct aead_alg *alg;
47	unsigned int ivsize;
48	unsigned int maxauthsize;
49	u32 mask;
50	int err;
51
52	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
53	if (err)
54		return ERR_PTR(err);
55
56	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
57	if (!inst)
58		return ERR_PTR(-ENOMEM);
59
60	spawn = aead_instance_ctx(inst);
61
62	err = crypto_grab_aead(spawn, aead_crypto_instance(inst),
63			       crypto_attr_alg_name(tb[1]), 0, mask);
64	if (err)
65		goto err_free_inst;
66
67	alg = crypto_spawn_aead_alg(spawn);
68
69	ivsize = crypto_aead_alg_ivsize(alg);
70	maxauthsize = crypto_aead_alg_maxauthsize(alg);
71
72	err = -EINVAL;
73	if (ivsize < sizeof(u64))
74		goto err_free_inst;
75
76	err = -ENAMETOOLONG;
77	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
78		     "%s(%s)", tmpl->name, alg->base.cra_name) >=
79	    CRYPTO_MAX_ALG_NAME)
80		goto err_free_inst;
81	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
82		     "%s(%s)", tmpl->name, alg->base.cra_driver_name) >=
83	    CRYPTO_MAX_ALG_NAME)
84		goto err_free_inst;
85
86	inst->alg.base.cra_priority = alg->base.cra_priority;
87	inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
88	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
89	inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
90
91	inst->alg.setkey = aead_geniv_setkey;
92	inst->alg.setauthsize = aead_geniv_setauthsize;
93
94	inst->alg.ivsize = ivsize;
95	inst->alg.maxauthsize = maxauthsize;
96
97	inst->free = aead_geniv_free;
98
99out:
100	return inst;
101
102err_free_inst:
103	aead_geniv_free(inst);
104	inst = ERR_PTR(err);
105	goto out;
106}
107EXPORT_SYMBOL_GPL(aead_geniv_alloc);
108
109int aead_init_geniv(struct crypto_aead *aead)
110{
111	struct aead_geniv_ctx *ctx = crypto_aead_ctx(aead);
112	struct aead_instance *inst = aead_alg_instance(aead);
113	struct crypto_aead *child;
114	int err;
115
116	spin_lock_init(&ctx->lock);
117
118	err = crypto_get_default_rng();
119	if (err)
120		goto out;
121
122	err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
123				   crypto_aead_ivsize(aead));
124	crypto_put_default_rng();
125	if (err)
126		goto out;
127
128	ctx->sknull = crypto_get_default_null_skcipher();
129	err = PTR_ERR(ctx->sknull);
130	if (IS_ERR(ctx->sknull))
131		goto out;
132
133	child = crypto_spawn_aead(aead_instance_ctx(inst));
134	err = PTR_ERR(child);
135	if (IS_ERR(child))
136		goto drop_null;
137
138	ctx->child = child;
139	crypto_aead_set_reqsize(aead, crypto_aead_reqsize(child) +
140				      sizeof(struct aead_request));
141
142	err = 0;
143
144out:
145	return err;
146
147drop_null:
148	crypto_put_default_null_skcipher();
149	goto out;
150}
151EXPORT_SYMBOL_GPL(aead_init_geniv);
152
153void aead_exit_geniv(struct crypto_aead *tfm)
154{
155	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
156
157	crypto_free_aead(ctx->child);
158	crypto_put_default_null_skcipher();
159}
160EXPORT_SYMBOL_GPL(aead_exit_geniv);
161
162MODULE_LICENSE("GPL");
163MODULE_DESCRIPTION("Shared IV generator code");
164