1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * CBC: Cipher Block Chaining mode 4 * 5 * Copyright (c) 2006-2016 Herbert Xu <herbert@gondor.apana.org.au> 6 */ 7 8 #include <crypto/algapi.h> 9 #include <crypto/cbc.h> 10 #include <crypto/internal/skcipher.h> 11 #include <linux/err.h> 12 #include <linux/init.h> 13 #include <linux/kernel.h> 14 #include <linux/log2.h> 15 #include <linux/module.h> 16 17 static inline void crypto_cbc_encrypt_one(struct crypto_skcipher *tfm, 18 const u8 *src, u8 *dst) 19 { 20 crypto_cipher_encrypt_one(skcipher_cipher_simple(tfm), dst, src); 21 } 22 23 static int crypto_cbc_encrypt(struct skcipher_request *req) 24 { 25 return crypto_cbc_encrypt_walk(req, crypto_cbc_encrypt_one); 26 } 27 28 static inline void crypto_cbc_decrypt_one(struct crypto_skcipher *tfm, 29 const u8 *src, u8 *dst) 30 { 31 crypto_cipher_decrypt_one(skcipher_cipher_simple(tfm), dst, src); 32 } 33 34 static int crypto_cbc_decrypt(struct skcipher_request *req) 35 { 36 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 37 struct skcipher_walk walk; 38 int err; 39 40 err = skcipher_walk_virt(&walk, req, false); 41 42 while (walk.nbytes) { 43 err = crypto_cbc_decrypt_blocks(&walk, tfm, 44 crypto_cbc_decrypt_one); 45 err = skcipher_walk_done(&walk, err); 46 } 47 48 return err; 49 } 50 51 static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb) 52 { 53 struct skcipher_instance *inst; 54 struct crypto_alg *alg; 55 int err; 56 57 inst = skcipher_alloc_instance_simple(tmpl, tb, &alg); 58 if (IS_ERR(inst)) 59 return PTR_ERR(inst); 60 61 err = -EINVAL; 62 if (!is_power_of_2(alg->cra_blocksize)) 63 goto out_free_inst; 64 65 inst->alg.encrypt = crypto_cbc_encrypt; 66 inst->alg.decrypt = crypto_cbc_decrypt; 67 68 err = skcipher_register_instance(tmpl, inst); 69 if (err) 70 goto out_free_inst; 71 goto out_put_alg; 72 73 out_free_inst: 74 inst->free(inst); 75 out_put_alg: 76 crypto_mod_put(alg); 77 return err; 78 } 79 80 static struct crypto_template crypto_cbc_tmpl = { 81 .name = "cbc", 82 .create = crypto_cbc_create, 83 .module = THIS_MODULE, 84 }; 85 86 static int __init crypto_cbc_module_init(void) 87 { 88 return crypto_register_template(&crypto_cbc_tmpl); 89 } 90 91 static void __exit crypto_cbc_module_exit(void) 92 { 93 crypto_unregister_template(&crypto_cbc_tmpl); 94 } 95 96 subsys_initcall(crypto_cbc_module_init); 97 module_exit(crypto_cbc_module_exit); 98 99 MODULE_LICENSE("GPL"); 100 MODULE_DESCRIPTION("CBC block cipher mode of operation"); 101 MODULE_ALIAS_CRYPTO("cbc"); 102