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c07f5d3d LB |
1 | /** |
2 | * AES XTS routines supporting VMX In-core instructions on Power 8 | |
3 | * | |
4 | * Copyright (C) 2015 International Business Machines Inc. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundations; version 2 only. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY of FITNESS FOR A PARTICUPAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
18 | * | |
19 | * Author: Leonidas S. Barbosa <leosilva@linux.vnet.ibm.com> | |
20 | */ | |
21 | ||
22 | #include <linux/types.h> | |
23 | #include <linux/err.h> | |
24 | #include <linux/crypto.h> | |
25 | #include <linux/delay.h> | |
26 | #include <linux/hardirq.h> | |
27 | #include <asm/switch_to.h> | |
28 | #include <crypto/aes.h> | |
29 | #include <crypto/scatterwalk.h> | |
30 | #include <crypto/xts.h> | |
5839f555 | 31 | #include <crypto/skcipher.h> |
c07f5d3d LB |
32 | |
33 | #include "aesp8-ppc.h" | |
34 | ||
35 | struct p8_aes_xts_ctx { | |
5839f555 | 36 | struct crypto_skcipher *fallback; |
c07f5d3d LB |
37 | struct aes_key enc_key; |
38 | struct aes_key dec_key; | |
39 | struct aes_key tweak_key; | |
40 | }; | |
41 | ||
42 | static int p8_aes_xts_init(struct crypto_tfm *tfm) | |
43 | { | |
44 | const char *alg; | |
5839f555 | 45 | struct crypto_skcipher *fallback; |
c07f5d3d LB |
46 | struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm); |
47 | ||
48 | if (!(alg = crypto_tfm_alg_name(tfm))) { | |
49 | printk(KERN_ERR "Failed to get algorithm name.\n"); | |
50 | return -ENOENT; | |
51 | } | |
52 | ||
5839f555 PFS |
53 | fallback = crypto_alloc_skcipher(alg, 0, |
54 | CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK); | |
c07f5d3d LB |
55 | if (IS_ERR(fallback)) { |
56 | printk(KERN_ERR | |
57 | "Failed to allocate transformation for '%s': %ld\n", | |
58 | alg, PTR_ERR(fallback)); | |
59 | return PTR_ERR(fallback); | |
60 | } | |
61 | printk(KERN_INFO "Using '%s' as fallback implementation.\n", | |
5839f555 | 62 | crypto_skcipher_driver_name(fallback)); |
c07f5d3d | 63 | |
5839f555 | 64 | crypto_skcipher_set_flags( |
c07f5d3d | 65 | fallback, |
5839f555 | 66 | crypto_skcipher_get_flags((struct crypto_skcipher *)tfm)); |
c07f5d3d LB |
67 | ctx->fallback = fallback; |
68 | ||
69 | return 0; | |
70 | } | |
71 | ||
72 | static void p8_aes_xts_exit(struct crypto_tfm *tfm) | |
73 | { | |
74 | struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm); | |
75 | ||
76 | if (ctx->fallback) { | |
5839f555 | 77 | crypto_free_skcipher(ctx->fallback); |
c07f5d3d LB |
78 | ctx->fallback = NULL; |
79 | } | |
80 | } | |
81 | ||
82 | static int p8_aes_xts_setkey(struct crypto_tfm *tfm, const u8 *key, | |
83 | unsigned int keylen) | |
84 | { | |
85 | int ret; | |
86 | struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm); | |
87 | ||
88 | ret = xts_check_key(tfm, key, keylen); | |
89 | if (ret) | |
90 | return ret; | |
91 | ||
92 | preempt_disable(); | |
93 | pagefault_disable(); | |
94 | enable_kernel_vsx(); | |
95 | ret = aes_p8_set_encrypt_key(key + keylen/2, (keylen/2) * 8, &ctx->tweak_key); | |
96 | ret += aes_p8_set_encrypt_key(key, (keylen/2) * 8, &ctx->enc_key); | |
97 | ret += aes_p8_set_decrypt_key(key, (keylen/2) * 8, &ctx->dec_key); | |
98 | disable_kernel_vsx(); | |
99 | pagefault_enable(); | |
100 | preempt_enable(); | |
101 | ||
5839f555 | 102 | ret += crypto_skcipher_setkey(ctx->fallback, key, keylen); |
c07f5d3d LB |
103 | return ret; |
104 | } | |
105 | ||
106 | static int p8_aes_xts_crypt(struct blkcipher_desc *desc, | |
107 | struct scatterlist *dst, | |
108 | struct scatterlist *src, | |
109 | unsigned int nbytes, int enc) | |
110 | { | |
111 | int ret; | |
112 | u8 tweak[AES_BLOCK_SIZE]; | |
113 | u8 *iv; | |
114 | struct blkcipher_walk walk; | |
115 | struct p8_aes_xts_ctx *ctx = | |
116 | crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm)); | |
c07f5d3d LB |
117 | |
118 | if (in_interrupt()) { | |
5839f555 PFS |
119 | SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback); |
120 | skcipher_request_set_tfm(req, ctx->fallback); | |
121 | skcipher_request_set_callback(req, desc->flags, NULL, NULL); | |
122 | skcipher_request_set_crypt(req, src, dst, nbytes, desc->info); | |
123 | ret = enc? crypto_skcipher_encrypt(req) : crypto_skcipher_decrypt(req); | |
124 | skcipher_request_zero(req); | |
c07f5d3d LB |
125 | } else { |
126 | preempt_disable(); | |
127 | pagefault_disable(); | |
128 | enable_kernel_vsx(); | |
129 | ||
130 | blkcipher_walk_init(&walk, dst, src, nbytes); | |
131 | ||
c07f5d3d | 132 | ret = blkcipher_walk_virt(desc, &walk); |
901d3d4f | 133 | iv = walk.iv; |
c07f5d3d LB |
134 | memset(tweak, 0, AES_BLOCK_SIZE); |
135 | aes_p8_encrypt(iv, tweak, &ctx->tweak_key); | |
136 | ||
137 | while ((nbytes = walk.nbytes)) { | |
138 | if (enc) | |
139 | aes_p8_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr, | |
140 | nbytes & AES_BLOCK_MASK, &ctx->enc_key, NULL, tweak); | |
141 | else | |
142 | aes_p8_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr, | |
143 | nbytes & AES_BLOCK_MASK, &ctx->dec_key, NULL, tweak); | |
144 | ||
145 | nbytes &= AES_BLOCK_SIZE - 1; | |
146 | ret = blkcipher_walk_done(desc, &walk, nbytes); | |
147 | } | |
148 | ||
149 | disable_kernel_vsx(); | |
150 | pagefault_enable(); | |
151 | preempt_enable(); | |
152 | } | |
153 | return ret; | |
154 | } | |
155 | ||
156 | static int p8_aes_xts_encrypt(struct blkcipher_desc *desc, | |
157 | struct scatterlist *dst, | |
158 | struct scatterlist *src, unsigned int nbytes) | |
159 | { | |
160 | return p8_aes_xts_crypt(desc, dst, src, nbytes, 1); | |
161 | } | |
162 | ||
163 | static int p8_aes_xts_decrypt(struct blkcipher_desc *desc, | |
164 | struct scatterlist *dst, | |
165 | struct scatterlist *src, unsigned int nbytes) | |
166 | { | |
167 | return p8_aes_xts_crypt(desc, dst, src, nbytes, 0); | |
168 | } | |
169 | ||
170 | struct crypto_alg p8_aes_xts_alg = { | |
171 | .cra_name = "xts(aes)", | |
172 | .cra_driver_name = "p8_aes_xts", | |
173 | .cra_module = THIS_MODULE, | |
174 | .cra_priority = 2000, | |
175 | .cra_type = &crypto_blkcipher_type, | |
176 | .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK, | |
177 | .cra_alignmask = 0, | |
178 | .cra_blocksize = AES_BLOCK_SIZE, | |
179 | .cra_ctxsize = sizeof(struct p8_aes_xts_ctx), | |
180 | .cra_init = p8_aes_xts_init, | |
181 | .cra_exit = p8_aes_xts_exit, | |
182 | .cra_blkcipher = { | |
183 | .ivsize = AES_BLOCK_SIZE, | |
184 | .min_keysize = 2 * AES_MIN_KEY_SIZE, | |
185 | .max_keysize = 2 * AES_MAX_KEY_SIZE, | |
186 | .setkey = p8_aes_xts_setkey, | |
187 | .encrypt = p8_aes_xts_encrypt, | |
188 | .decrypt = p8_aes_xts_decrypt, | |
189 | } | |
190 | }; |