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2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771 
 kernel/crypto/cbc.c
....@@ -1,190 +1,202 @@
1
+// SPDX-License-Identifier: GPL-2.0-or-later
12 /*
23  * CBC: Cipher Block Chaining mode
34  *
45  * Copyright (c) 2006-2016 Herbert Xu <herbert@gondor.apana.org.au>
5
- *
6
- * This program is free software; you can redistribute it and/or modify it
7
- * under the terms of the GNU General Public License as published by the Free
8
- * Software Foundation; either version 2 of the License, or (at your option)
9
- * any later version.
10
- *
116  */
127 
138 #include <crypto/algapi.h>
14
-#include <crypto/cbc.h>
9
+#include <crypto/internal/cipher.h>
1510 #include <crypto/internal/skcipher.h>
1611 #include <linux/err.h>
1712 #include <linux/init.h>
1813 #include <linux/kernel.h>
1914 #include <linux/log2.h>
2015 #include <linux/module.h>
21
-#include <linux/slab.h>
2216 
23
-struct crypto_cbc_ctx {
24
-	struct crypto_cipher *child;
25
-};
26
-
27
-static int crypto_cbc_setkey(struct crypto_skcipher *parent, const u8 *key,
28
-			     unsigned int keylen)
17
+static int crypto_cbc_encrypt_segment(struct skcipher_walk *walk,
18
+				      struct crypto_skcipher *skcipher)
2919 {
30
-	struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(parent);
31
-	struct crypto_cipher *child = ctx->child;
32
-	int err;
20
+	unsigned int bsize = crypto_skcipher_blocksize(skcipher);
21
+	void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
22
+	unsigned int nbytes = walk->nbytes;
23
+	u8 *src = walk->src.virt.addr;
24
+	u8 *dst = walk->dst.virt.addr;
25
+	struct crypto_cipher *cipher;
26
+	struct crypto_tfm *tfm;
27
+	u8 *iv = walk->iv;
3328 
34
-	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
35
-	crypto_cipher_set_flags(child, crypto_skcipher_get_flags(parent) &
36
-				       CRYPTO_TFM_REQ_MASK);
37
-	err = crypto_cipher_setkey(child, key, keylen);
38
-	crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(child) &
39
-					  CRYPTO_TFM_RES_MASK);
40
-	return err;
29
+	cipher = skcipher_cipher_simple(skcipher);
30
+	tfm = crypto_cipher_tfm(cipher);
31
+	fn = crypto_cipher_alg(cipher)->cia_encrypt;
32
+
33
+	do {
34
+		crypto_xor(iv, src, bsize);
35
+		fn(tfm, dst, iv);
36
+		memcpy(iv, dst, bsize);
37
+
38
+		src += bsize;
39
+		dst += bsize;
40
+	} while ((nbytes -= bsize) >= bsize);
41
+
42
+	return nbytes;
4143 }
4244 
43
-static inline void crypto_cbc_encrypt_one(struct crypto_skcipher *tfm,
44
-					  const u8 *src, u8 *dst)
45
+static int crypto_cbc_encrypt_inplace(struct skcipher_walk *walk,
46
+				      struct crypto_skcipher *skcipher)
4547 {
46
-	struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
48
+	unsigned int bsize = crypto_skcipher_blocksize(skcipher);
49
+	void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
50
+	unsigned int nbytes = walk->nbytes;
51
+	u8 *src = walk->src.virt.addr;
52
+	struct crypto_cipher *cipher;
53
+	struct crypto_tfm *tfm;
54
+	u8 *iv = walk->iv;
4755 
48
-	crypto_cipher_encrypt_one(ctx->child, dst, src);
56
+	cipher = skcipher_cipher_simple(skcipher);
57
+	tfm = crypto_cipher_tfm(cipher);
58
+	fn = crypto_cipher_alg(cipher)->cia_encrypt;
59
+
60
+	do {
61
+		crypto_xor(src, iv, bsize);
62
+		fn(tfm, src, src);
63
+		iv = src;
64
+
65
+		src += bsize;
66
+	} while ((nbytes -= bsize) >= bsize);
67
+
68
+	memcpy(walk->iv, iv, bsize);
69
+
70
+	return nbytes;
4971 }
5072 
5173 static int crypto_cbc_encrypt(struct skcipher_request *req)
5274 {
53
-	return crypto_cbc_encrypt_walk(req, crypto_cbc_encrypt_one);
54
-}
55
-
56
-static inline void crypto_cbc_decrypt_one(struct crypto_skcipher *tfm,
57
-					  const u8 *src, u8 *dst)
58
-{
59
-	struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
60
-
61
-	crypto_cipher_decrypt_one(ctx->child, dst, src);
62
-}
63
-
64
-static int crypto_cbc_decrypt(struct skcipher_request *req)
65
-{
66
-	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
75
+	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
6776 	struct skcipher_walk walk;
6877 	int err;
6978 
7079 	err = skcipher_walk_virt(&walk, req, false);
7180 
7281 	while (walk.nbytes) {
73
-		err = crypto_cbc_decrypt_blocks(&walk, tfm,
74
-						crypto_cbc_decrypt_one);
82
+		if (walk.src.virt.addr == walk.dst.virt.addr)
83
+			err = crypto_cbc_encrypt_inplace(&walk, skcipher);
84
+		else
85
+			err = crypto_cbc_encrypt_segment(&walk, skcipher);
7586 		err = skcipher_walk_done(&walk, err);
7687 	}
7788 
7889 	return err;
7990 }
8091 
81
-static int crypto_cbc_init_tfm(struct crypto_skcipher *tfm)
92
+static int crypto_cbc_decrypt_segment(struct skcipher_walk *walk,
93
+				      struct crypto_skcipher *skcipher)
8294 {
83
-	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
84
-	struct crypto_spawn *spawn = skcipher_instance_ctx(inst);
85
-	struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
95
+	unsigned int bsize = crypto_skcipher_blocksize(skcipher);
96
+	void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
97
+	unsigned int nbytes = walk->nbytes;
98
+	u8 *src = walk->src.virt.addr;
99
+	u8 *dst = walk->dst.virt.addr;
86100 	struct crypto_cipher *cipher;
101
+	struct crypto_tfm *tfm;
102
+	u8 *iv = walk->iv;
87103 
88
-	cipher = crypto_spawn_cipher(spawn);
89
-	if (IS_ERR(cipher))
90
-		return PTR_ERR(cipher);
104
+	cipher = skcipher_cipher_simple(skcipher);
105
+	tfm = crypto_cipher_tfm(cipher);
106
+	fn = crypto_cipher_alg(cipher)->cia_decrypt;
91107 
92
-	ctx->child = cipher;
93
-	return 0;
108
+	do {
109
+		fn(tfm, dst, src);
110
+		crypto_xor(dst, iv, bsize);
111
+		iv = src;
112
+
113
+		src += bsize;
114
+		dst += bsize;
115
+	} while ((nbytes -= bsize) >= bsize);
116
+
117
+	memcpy(walk->iv, iv, bsize);
118
+
119
+	return nbytes;
94120 }
95121 
96
-static void crypto_cbc_exit_tfm(struct crypto_skcipher *tfm)
122
+static int crypto_cbc_decrypt_inplace(struct skcipher_walk *walk,
123
+				      struct crypto_skcipher *skcipher)
97124 {
98
-	struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
125
+	unsigned int bsize = crypto_skcipher_blocksize(skcipher);
126
+	void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
127
+	unsigned int nbytes = walk->nbytes;
128
+	u8 *src = walk->src.virt.addr;
129
+	u8 last_iv[MAX_CIPHER_BLOCKSIZE];
130
+	struct crypto_cipher *cipher;
131
+	struct crypto_tfm *tfm;
99132 
100
-	crypto_free_cipher(ctx->child);
133
+	cipher = skcipher_cipher_simple(skcipher);
134
+	tfm = crypto_cipher_tfm(cipher);
135
+	fn = crypto_cipher_alg(cipher)->cia_decrypt;
136
+
137
+	/* Start of the last block. */
138
+	src += nbytes - (nbytes & (bsize - 1)) - bsize;
139
+	memcpy(last_iv, src, bsize);
140
+
141
+	for (;;) {
142
+		fn(tfm, src, src);
143
+		if ((nbytes -= bsize) < bsize)
144
+			break;
145
+		crypto_xor(src, src - bsize, bsize);
146
+		src -= bsize;
147
+	}
148
+
149
+	crypto_xor(src, walk->iv, bsize);
150
+	memcpy(walk->iv, last_iv, bsize);
151
+
152
+	return nbytes;
101153 }
102154 
103
-static void crypto_cbc_free(struct skcipher_instance *inst)
155
+static int crypto_cbc_decrypt(struct skcipher_request *req)
104156 {
105
-	crypto_drop_skcipher(skcipher_instance_ctx(inst));
106
-	kfree(inst);
157
+	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
158
+	struct skcipher_walk walk;
159
+	int err;
160
+
161
+	err = skcipher_walk_virt(&walk, req, false);
162
+
163
+	while (walk.nbytes) {
164
+		if (walk.src.virt.addr == walk.dst.virt.addr)
165
+			err = crypto_cbc_decrypt_inplace(&walk, skcipher);
166
+		else
167
+			err = crypto_cbc_decrypt_segment(&walk, skcipher);
168
+		err = skcipher_walk_done(&walk, err);
169
+	}
170
+
171
+	return err;
107172 }
108173 
109174 static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
110175 {
111176 	struct skcipher_instance *inst;
112
-	struct crypto_attr_type *algt;
113
-	struct crypto_spawn *spawn;
114177 	struct crypto_alg *alg;
115
-	u32 mask;
116178 	int err;
117179 
118
-	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER);
119
-	if (err)
120
-		return err;
180
+	inst = skcipher_alloc_instance_simple(tmpl, tb);
181
+	if (IS_ERR(inst))
182
+		return PTR_ERR(inst);
121183 
122
-	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
123
-	if (!inst)
124
-		return -ENOMEM;
125
-
126
-	algt = crypto_get_attr_type(tb);
127
-	err = PTR_ERR(algt);
128
-	if (IS_ERR(algt))
129
-		goto err_free_inst;
130
-
131
-	mask = CRYPTO_ALG_TYPE_MASK |
132
-		crypto_requires_off(algt->type, algt->mask,
133
-				    CRYPTO_ALG_NEED_FALLBACK);
134
-
135
-	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, mask);
136
-	err = PTR_ERR(alg);
137
-	if (IS_ERR(alg))
138
-		goto err_free_inst;
139
-
140
-	spawn = skcipher_instance_ctx(inst);
141
-	err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
142
-				CRYPTO_ALG_TYPE_MASK);
143
-	if (err)
144
-		goto err_put_alg;
145
-
146
-	err = crypto_inst_setname(skcipher_crypto_instance(inst), "cbc", alg);
147
-	if (err)
148
-		goto err_drop_spawn;
184
+	alg = skcipher_ialg_simple(inst);
149185 
150186 	err = -EINVAL;
151187 	if (!is_power_of_2(alg->cra_blocksize))
152
-		goto err_drop_spawn;
188
+		goto out_free_inst;
153189 
154
-	inst->alg.base.cra_priority = alg->cra_priority;
155
-	inst->alg.base.cra_blocksize = alg->cra_blocksize;
156
-	inst->alg.base.cra_alignmask = alg->cra_alignmask;
157
-
158
-	inst->alg.ivsize = alg->cra_blocksize;
159
-	inst->alg.min_keysize = alg->cra_cipher.cia_min_keysize;
160
-	inst->alg.max_keysize = alg->cra_cipher.cia_max_keysize;
161
-
162
-	inst->alg.base.cra_ctxsize = sizeof(struct crypto_cbc_ctx);
163
-
164
-	inst->alg.init = crypto_cbc_init_tfm;
165
-	inst->alg.exit = crypto_cbc_exit_tfm;
166
-
167
-	inst->alg.setkey = crypto_cbc_setkey;
168190 	inst->alg.encrypt = crypto_cbc_encrypt;
169191 	inst->alg.decrypt = crypto_cbc_decrypt;
170192 
171
-	inst->free = crypto_cbc_free;
172
-
173193 	err = skcipher_register_instance(tmpl, inst);
174
-	if (err)
175
-		goto err_drop_spawn;
176
-	crypto_mod_put(alg);
194
+	if (err) {
195
+out_free_inst:
196
+		inst->free(inst);
197
+	}
177198 
178
-out:
179199 	return err;
180
-
181
-err_drop_spawn:
182
-	crypto_drop_spawn(spawn);
183
-err_put_alg:
184
-	crypto_mod_put(alg);
185
-err_free_inst:
186
-	kfree(inst);
187
-	goto out;
188200 }
189201 
190202 static struct crypto_template crypto_cbc_tmpl = {
....@@ -203,9 +215,9 @@
203215 	crypto_unregister_template(&crypto_cbc_tmpl);
204216 }
205217 
206
-module_init(crypto_cbc_module_init);
218
+subsys_initcall(crypto_cbc_module_init);
207219 module_exit(crypto_cbc_module_exit);
208220 
209221 MODULE_LICENSE("GPL");
210
-MODULE_DESCRIPTION("CBC block cipher algorithm");
222
+MODULE_DESCRIPTION("CBC block cipher mode of operation");
211223 MODULE_ALIAS_CRYPTO("cbc");