1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * AES XTS routines supporting VMX In-core instructions on Power 8
4 *
5 * Copyright (C) 2015 International Business Machines Inc.
6 *
7 * Author: Leonidas S. Barbosa <leosilva@linux.vnet.ibm.com>
8 */
9
10#include <asm/simd.h>
11#include <asm/switch_to.h>
12#include <crypto/aes.h>
13#include <crypto/internal/simd.h>
14#include <crypto/internal/skcipher.h>
15#include <crypto/xts.h>
16
17#include "aesp8-ppc.h"
18
19struct p8_aes_xts_ctx {
20 struct crypto_skcipher *fallback;
21 struct aes_key enc_key;
22 struct aes_key dec_key;
23 struct aes_key tweak_key;
24};
25
26static int p8_aes_xts_init(struct crypto_skcipher *tfm)
27{
28 struct p8_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
29 struct crypto_skcipher *fallback;
30
31 fallback = crypto_alloc_skcipher(alg_name: "xts(aes)", type: 0,
32 CRYPTO_ALG_NEED_FALLBACK |
33 CRYPTO_ALG_ASYNC);
34 if (IS_ERR(ptr: fallback)) {
35 pr_err("Failed to allocate xts(aes) fallback: %ld\n",
36 PTR_ERR(fallback));
37 return PTR_ERR(ptr: fallback);
38 }
39
40 crypto_skcipher_set_reqsize(skcipher: tfm, reqsize: sizeof(struct skcipher_request) +
41 crypto_skcipher_reqsize(tfm: fallback));
42 ctx->fallback = fallback;
43 return 0;
44}
45
46static void p8_aes_xts_exit(struct crypto_skcipher *tfm)
47{
48 struct p8_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
49
50 crypto_free_skcipher(tfm: ctx->fallback);
51}
52
53static int p8_aes_xts_setkey(struct crypto_skcipher *tfm, const u8 *key,
54 unsigned int keylen)
55{
56 struct p8_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
57 int ret;
58
59 ret = xts_verify_key(tfm, key, keylen);
60 if (ret)
61 return ret;
62
63 preempt_disable();
64 pagefault_disable();
65 enable_kernel_vsx();
66 ret = aes_p8_set_encrypt_key(userKey: key + keylen/2, bits: (keylen/2) * 8, key: &ctx->tweak_key);
67 ret |= aes_p8_set_encrypt_key(userKey: key, bits: (keylen/2) * 8, key: &ctx->enc_key);
68 ret |= aes_p8_set_decrypt_key(userKey: key, bits: (keylen/2) * 8, key: &ctx->dec_key);
69 disable_kernel_vsx();
70 pagefault_enable();
71 preempt_enable();
72
73 ret |= crypto_skcipher_setkey(tfm: ctx->fallback, key, keylen);
74
75 return ret ? -EINVAL : 0;
76}
77
78static int p8_aes_xts_crypt(struct skcipher_request *req, int enc)
79{
80 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
81 const struct p8_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
82 struct skcipher_walk walk;
83 unsigned int nbytes;
84 u8 tweak[AES_BLOCK_SIZE];
85 int ret;
86
87 if (req->cryptlen < AES_BLOCK_SIZE)
88 return -EINVAL;
89
90 if (!crypto_simd_usable() || (req->cryptlen % XTS_BLOCK_SIZE) != 0) {
91 struct skcipher_request *subreq = skcipher_request_ctx(req);
92
93 *subreq = *req;
94 skcipher_request_set_tfm(req: subreq, tfm: ctx->fallback);
95 return enc ? crypto_skcipher_encrypt(req: subreq) :
96 crypto_skcipher_decrypt(req: subreq);
97 }
98
99 ret = skcipher_walk_virt(walk: &walk, req, atomic: false);
100 if (ret)
101 return ret;
102
103 preempt_disable();
104 pagefault_disable();
105 enable_kernel_vsx();
106
107 aes_p8_encrypt(in: walk.iv, out: tweak, key: &ctx->tweak_key);
108
109 disable_kernel_vsx();
110 pagefault_enable();
111 preempt_enable();
112
113 while ((nbytes = walk.nbytes) != 0) {
114 preempt_disable();
115 pagefault_disable();
116 enable_kernel_vsx();
117 if (enc)
118 aes_p8_xts_encrypt(in: walk.src.virt.addr,
119 out: walk.dst.virt.addr,
120 round_down(nbytes, AES_BLOCK_SIZE),
121 key1: &ctx->enc_key, NULL, iv: tweak);
122 else
123 aes_p8_xts_decrypt(in: walk.src.virt.addr,
124 out: walk.dst.virt.addr,
125 round_down(nbytes, AES_BLOCK_SIZE),
126 key1: &ctx->dec_key, NULL, iv: tweak);
127 disable_kernel_vsx();
128 pagefault_enable();
129 preempt_enable();
130
131 ret = skcipher_walk_done(walk: &walk, err: nbytes % AES_BLOCK_SIZE);
132 }
133 return ret;
134}
135
136static int p8_aes_xts_encrypt(struct skcipher_request *req)
137{
138 return p8_aes_xts_crypt(req, enc: 1);
139}
140
141static int p8_aes_xts_decrypt(struct skcipher_request *req)
142{
143 return p8_aes_xts_crypt(req, enc: 0);
144}
145
146struct skcipher_alg p8_aes_xts_alg = {
147 .base.cra_name = "xts(aes)",
148 .base.cra_driver_name = "p8_aes_xts",
149 .base.cra_module = THIS_MODULE,
150 .base.cra_priority = 2000,
151 .base.cra_flags = CRYPTO_ALG_NEED_FALLBACK,
152 .base.cra_blocksize = AES_BLOCK_SIZE,
153 .base.cra_ctxsize = sizeof(struct p8_aes_xts_ctx),
154 .setkey = p8_aes_xts_setkey,
155 .encrypt = p8_aes_xts_encrypt,
156 .decrypt = p8_aes_xts_decrypt,
157 .init = p8_aes_xts_init,
158 .exit = p8_aes_xts_exit,
159 .min_keysize = 2 * AES_MIN_KEY_SIZE,
160 .max_keysize = 2 * AES_MAX_KEY_SIZE,
161 .ivsize = AES_BLOCK_SIZE,
162};
163

source code of linux/arch/powerpc/crypto/aes_xts.c