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(tfm: 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(tfm: ctx->child, authsize);
33}
34
35static void aead_geniv_free(struct aead_instance *inst)
36{
37 crypto_drop_aead(spawn: aead_instance_ctx(inst));
38 kfree(objp: 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_ret: &mask);
53 if (err)
54 return ERR_PTR(error: err);
55
56 inst = kzalloc(size: sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
57 if (!inst)
58 return ERR_PTR(error: -ENOMEM);
59
60 spawn = aead_instance_ctx(inst);
61
62 err = crypto_grab_aead(spawn, inst: aead_crypto_instance(inst),
63 name: crypto_attr_alg_name(rta: tb[1]), type: 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(buf: inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
78 fmt: "%s(%s)", tmpl->name, alg->base.cra_name) >=
79 CRYPTO_MAX_ALG_NAME)
80 goto err_free_inst;
81 if (snprintf(buf: inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
82 fmt: "%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(error: 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(tfm: 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(tfm: crypto_default_rng, rdata: ctx->salt,
123 dlen: crypto_aead_ivsize(tfm: 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(ptr: ctx->sknull);
130 if (IS_ERR(ptr: ctx->sknull))
131 goto out;
132
133 child = crypto_spawn_aead(spawn: aead_instance_ctx(inst));
134 err = PTR_ERR(ptr: child);
135 if (IS_ERR(ptr: child))
136 goto drop_null;
137
138 ctx->child = child;
139 crypto_aead_set_reqsize(aead, reqsize: crypto_aead_reqsize(tfm: 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(tfm: 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

source code of linux/crypto/geniv.c