the-tree/crypto/xcbc.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Copyright (C)2006 USAGI/WIDE Project
0004  *
0005  * Author:
0006  *  Kazunori Miyazawa <miyazawa@linux-ipv6.org>
0007  */
0008
0009 #include <crypto/internal/cipher.h>
0010 #include <crypto/internal/hash.h>
0011 #include <linux/err.h>
0012 #include <linux/kernel.h>
0013 #include <linux/module.h>
0014
0015 static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
0016                0x02020202, 0x02020202, 0x02020202, 0x02020202,
0017                0x03030303, 0x03030303, 0x03030303, 0x03030303};
0018
0019 /*
0020  * +------------------------
0021  * | <parent tfm>
0022  * +------------------------
0023  * | xcbc_tfm_ctx
0024  * +------------------------
0025  * | consts (block size * 2)
0026  * +------------------------
0027  */
0028 struct xcbc_tfm_ctx {
0029     struct crypto_cipher *child;
0030     u8 ctx[];
0031 };
0032
0033 /*
0034  * +------------------------
0035  * | <shash desc>
0036  * +------------------------
0037  * | xcbc_desc_ctx
0038  * +------------------------
0039  * | odds (block size)
0040  * +------------------------
0041  * | prev (block size)
0042  * +------------------------
0043  */
0044 struct xcbc_desc_ctx {
0045     unsigned int len;
0046     u8 ctx[];
0047 };
0048
0049 #define XCBC_BLOCKSIZE  16
0050
0051 static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,
0052                      const u8 *inkey, unsigned int keylen)
0053 {
0054     unsigned long alignmask = crypto_shash_alignmask(parent);
0055     struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent);
0056     u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
0057     int err = 0;
0058     u8 key1[XCBC_BLOCKSIZE];
0059     int bs = sizeof(key1);
0060
0061     if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen)))
0062         return err;
0063
0064     crypto_cipher_encrypt_one(ctx->child, consts, (u8 *)ks + bs);
0065     crypto_cipher_encrypt_one(ctx->child, consts + bs, (u8 *)ks + bs * 2);
0066     crypto_cipher_encrypt_one(ctx->child, key1, (u8 *)ks);
0067
0068     return crypto_cipher_setkey(ctx->child, key1, bs);
0069
0070 }
0071
0072 static int crypto_xcbc_digest_init(struct shash_desc *pdesc)
0073 {
0074     unsigned long alignmask = crypto_shash_alignmask(pdesc->tfm);
0075     struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
0076     int bs = crypto_shash_blocksize(pdesc->tfm);
0077     u8 *prev = PTR_ALIGN(&ctx->ctx[0], alignmask + 1) + bs;
0078
0079     ctx->len = 0;
0080     memset(prev, 0, bs);
0081
0082     return 0;
0083 }
0084
0085 static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p,
0086                      unsigned int len)
0087 {
0088     struct crypto_shash *parent = pdesc->tfm;
0089     unsigned long alignmask = crypto_shash_alignmask(parent);
0090     struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
0091     struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
0092     struct crypto_cipher *tfm = tctx->child;
0093     int bs = crypto_shash_blocksize(parent);
0094     u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
0095     u8 *prev = odds + bs;
0096
0097     /* checking the data can fill the block */
0098     if ((ctx->len + len) <= bs) {
0099         memcpy(odds + ctx->len, p, len);
0100         ctx->len += len;
0101         return 0;
0102     }
0103
0104     /* filling odds with new data and encrypting it */
0105     memcpy(odds + ctx->len, p, bs - ctx->len);
0106     len -= bs - ctx->len;
0107     p += bs - ctx->len;
0108
0109     crypto_xor(prev, odds, bs);
0110     crypto_cipher_encrypt_one(tfm, prev, prev);
0111
0112     /* clearing the length */
0113     ctx->len = 0;
0114
0115     /* encrypting the rest of data */
0116     while (len > bs) {
0117         crypto_xor(prev, p, bs);
0118         crypto_cipher_encrypt_one(tfm, prev, prev);
0119         p += bs;
0120         len -= bs;
0121     }
0122
0123     /* keeping the surplus of blocksize */
0124     if (len) {
0125         memcpy(odds, p, len);
0126         ctx->len = len;
0127     }
0128
0129     return 0;
0130 }
0131
0132 static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out)
0133 {
0134     struct crypto_shash *parent = pdesc->tfm;
0135     unsigned long alignmask = crypto_shash_alignmask(parent);
0136     struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
0137     struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
0138     struct crypto_cipher *tfm = tctx->child;
0139     int bs = crypto_shash_blocksize(parent);
0140     u8 *consts = PTR_ALIGN(&tctx->ctx[0], alignmask + 1);
0141     u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
0142     u8 *prev = odds + bs;
0143     unsigned int offset = 0;
0144
0145     if (ctx->len != bs) {
0146         unsigned int rlen;
0147         u8 *p = odds + ctx->len;
0148
0149         *p = 0x80;
0150         p++;
0151
0152         rlen = bs - ctx->len -1;
0153         if (rlen)
0154             memset(p, 0, rlen);
0155
0156         offset += bs;
0157     }
0158
0159     crypto_xor(prev, odds, bs);
0160     crypto_xor(prev, consts + offset, bs);
0161
0162     crypto_cipher_encrypt_one(tfm, out, prev);
0163
0164     return 0;
0165 }
0166
0167 static int xcbc_init_tfm(struct crypto_tfm *tfm)
0168 {
0169     struct crypto_cipher *cipher;
0170     struct crypto_instance *inst = (void *)tfm->__crt_alg;
0171     struct crypto_cipher_spawn *spawn = crypto_instance_ctx(inst);
0172     struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
0173
0174     cipher = crypto_spawn_cipher(spawn);
0175     if (IS_ERR(cipher))
0176         return PTR_ERR(cipher);
0177
0178     ctx->child = cipher;
0179
0180     return 0;
0181 };
0182
0183 static void xcbc_exit_tfm(struct crypto_tfm *tfm)
0184 {
0185     struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
0186     crypto_free_cipher(ctx->child);
0187 }
0188
0189 static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
0190 {
0191     struct shash_instance *inst;
0192     struct crypto_cipher_spawn *spawn;
0193     struct crypto_alg *alg;
0194     unsigned long alignmask;
0195     u32 mask;
0196     int err;
0197
0198     err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH, &mask);
0199     if (err)
0200         return err;
0201
0202     inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
0203     if (!inst)
0204         return -ENOMEM;
0205     spawn = shash_instance_ctx(inst);
0206
0207     err = crypto_grab_cipher(spawn, shash_crypto_instance(inst),
0208                  crypto_attr_alg_name(tb[1]), 0, mask);
0209     if (err)
0210         goto err_free_inst;
0211     alg = crypto_spawn_cipher_alg(spawn);
0212
0213     err = -EINVAL;
0214     if (alg->cra_blocksize != XCBC_BLOCKSIZE)
0215         goto err_free_inst;
0216
0217     err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg);
0218     if (err)
0219         goto err_free_inst;
0220
0221     alignmask = alg->cra_alignmask | 3;
0222     inst->alg.base.cra_alignmask = alignmask;
0223     inst->alg.base.cra_priority = alg->cra_priority;
0224     inst->alg.base.cra_blocksize = alg->cra_blocksize;
0225
0226     inst->alg.digestsize = alg->cra_blocksize;
0227     inst->alg.descsize = ALIGN(sizeof(struct xcbc_desc_ctx),
0228                    crypto_tfm_ctx_alignment()) +
0229                  (alignmask &
0230                   ~(crypto_tfm_ctx_alignment() - 1)) +
0231                  alg->cra_blocksize * 2;
0232
0233     inst->alg.base.cra_ctxsize = ALIGN(sizeof(struct xcbc_tfm_ctx),
0234                        alignmask + 1) +
0235                      alg->cra_blocksize * 2;
0236     inst->alg.base.cra_init = xcbc_init_tfm;
0237     inst->alg.base.cra_exit = xcbc_exit_tfm;
0238
0239     inst->alg.init = crypto_xcbc_digest_init;
0240     inst->alg.update = crypto_xcbc_digest_update;
0241     inst->alg.final = crypto_xcbc_digest_final;
0242     inst->alg.setkey = crypto_xcbc_digest_setkey;
0243
0244     inst->free = shash_free_singlespawn_instance;
0245
0246     err = shash_register_instance(tmpl, inst);
0247     if (err) {
0248 err_free_inst:
0249         shash_free_singlespawn_instance(inst);
0250     }
0251     return err;
0252 }
0253
0254 static struct crypto_template crypto_xcbc_tmpl = {
0255     .name = "xcbc",
0256     .create = xcbc_create,
0257     .module = THIS_MODULE,
0258 };
0259
0260 static int __init crypto_xcbc_module_init(void)
0261 {
0262     return crypto_register_template(&crypto_xcbc_tmpl);
0263 }
0264
0265 static void __exit crypto_xcbc_module_exit(void)
0266 {
0267     crypto_unregister_template(&crypto_xcbc_tmpl);
0268 }
0269
0270 subsys_initcall(crypto_xcbc_module_init);
0271 module_exit(crypto_xcbc_module_exit);
0272
0273 MODULE_LICENSE("GPL");
0274 MODULE_DESCRIPTION("XCBC keyed hash algorithm");
0275 MODULE_ALIAS_CRYPTO("xcbc");
0276 MODULE_IMPORT_NS(CRYPTO_INTERNAL);