164470f1bSRik Snel /* LRW: as defined by Cyril Guyot in 264470f1bSRik Snel * http://grouper.ieee.org/groups/1619/email/pdf00017.pdf 364470f1bSRik Snel * 464470f1bSRik Snel * Copyright (c) 2006 Rik Snel <rsnel@cube.dyndns.org> 564470f1bSRik Snel * 664470f1bSRik Snel * Based om ecb.c 764470f1bSRik Snel * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au> 864470f1bSRik Snel * 964470f1bSRik Snel * This program is free software; you can redistribute it and/or modify it 1064470f1bSRik Snel * under the terms of the GNU General Public License as published by the Free 1164470f1bSRik Snel * Software Foundation; either version 2 of the License, or (at your option) 1264470f1bSRik Snel * any later version. 1364470f1bSRik Snel */ 1464470f1bSRik Snel /* This implementation is checked against the test vectors in the above 1564470f1bSRik Snel * document and by a test vector provided by Ken Buchanan at 1664470f1bSRik Snel * http://www.mail-archive.com/stds-p1619@listserv.ieee.org/msg00173.html 1764470f1bSRik Snel * 1864470f1bSRik Snel * The test vectors are included in the testing module tcrypt.[ch] */ 1964470f1bSRik Snel #include <crypto/algapi.h> 2064470f1bSRik Snel #include <linux/err.h> 2164470f1bSRik Snel #include <linux/init.h> 2264470f1bSRik Snel #include <linux/kernel.h> 2364470f1bSRik Snel #include <linux/module.h> 2464470f1bSRik Snel #include <linux/scatterlist.h> 2564470f1bSRik Snel #include <linux/slab.h> 2664470f1bSRik Snel 2764470f1bSRik Snel #include <crypto/b128ops.h> 2864470f1bSRik Snel #include <crypto/gf128mul.h> 2964470f1bSRik Snel 3064470f1bSRik Snel struct priv { 3164470f1bSRik Snel struct crypto_cipher *child; 3264470f1bSRik Snel /* optimizes multiplying a random (non incrementing, as at the 3364470f1bSRik Snel * start of a new sector) value with key2, we could also have 3464470f1bSRik Snel * used 4k optimization tables or no optimization at all. In the 3564470f1bSRik Snel * latter case we would have to store key2 here */ 3664470f1bSRik Snel struct gf128mul_64k *table; 3764470f1bSRik Snel /* stores: 3864470f1bSRik Snel * key2*{ 0,0,...0,0,0,0,1 }, key2*{ 0,0,...0,0,0,1,1 }, 3964470f1bSRik Snel * key2*{ 0,0,...0,0,1,1,1 }, key2*{ 0,0,...0,1,1,1,1 } 4064470f1bSRik Snel * key2*{ 0,0,...1,1,1,1,1 }, etc 4164470f1bSRik Snel * needed for optimized multiplication of incrementing values 4264470f1bSRik Snel * with key2 */ 4364470f1bSRik Snel be128 mulinc[128]; 4464470f1bSRik Snel }; 4564470f1bSRik Snel 4664470f1bSRik Snel static inline void setbit128_bbe(void *b, int bit) 4764470f1bSRik Snel { 4864470f1bSRik Snel __set_bit(bit ^ 0x78, b); 4964470f1bSRik Snel } 5064470f1bSRik Snel 5164470f1bSRik Snel static int setkey(struct crypto_tfm *parent, const u8 *key, 5264470f1bSRik Snel unsigned int keylen) 5364470f1bSRik Snel { 5464470f1bSRik Snel struct priv *ctx = crypto_tfm_ctx(parent); 5564470f1bSRik Snel struct crypto_cipher *child = ctx->child; 5664470f1bSRik Snel int err, i; 5764470f1bSRik Snel be128 tmp = { 0 }; 5864470f1bSRik Snel int bsize = crypto_cipher_blocksize(child); 5964470f1bSRik Snel 6064470f1bSRik Snel crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK); 6164470f1bSRik Snel crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) & 6264470f1bSRik Snel CRYPTO_TFM_REQ_MASK); 6364470f1bSRik Snel if ((err = crypto_cipher_setkey(child, key, keylen - bsize))) 6464470f1bSRik Snel return err; 6564470f1bSRik Snel crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) & 6664470f1bSRik Snel CRYPTO_TFM_RES_MASK); 6764470f1bSRik Snel 6864470f1bSRik Snel if (ctx->table) 6964470f1bSRik Snel gf128mul_free_64k(ctx->table); 7064470f1bSRik Snel 7164470f1bSRik Snel /* initialize multiplication table for Key2 */ 7264470f1bSRik Snel ctx->table = gf128mul_init_64k_bbe((be128 *)(key + keylen - bsize)); 7364470f1bSRik Snel if (!ctx->table) 7464470f1bSRik Snel return -ENOMEM; 7564470f1bSRik Snel 7664470f1bSRik Snel /* initialize optimization table */ 7764470f1bSRik Snel for (i = 0; i < 128; i++) { 7864470f1bSRik Snel setbit128_bbe(&tmp, i); 7964470f1bSRik Snel ctx->mulinc[i] = tmp; 8064470f1bSRik Snel gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table); 8164470f1bSRik Snel } 8264470f1bSRik Snel 8364470f1bSRik Snel return 0; 8464470f1bSRik Snel } 8564470f1bSRik Snel 8664470f1bSRik Snel struct sinfo { 8764470f1bSRik Snel be128 t; 8864470f1bSRik Snel struct crypto_tfm *tfm; 8964470f1bSRik Snel void (*fn)(struct crypto_tfm *, u8 *, const u8 *); 9064470f1bSRik Snel }; 9164470f1bSRik Snel 9264470f1bSRik Snel static inline void inc(be128 *iv) 9364470f1bSRik Snel { 9464470f1bSRik Snel if (!(iv->b = cpu_to_be64(be64_to_cpu(iv->b) + 1))) 9564470f1bSRik Snel iv->a = cpu_to_be64(be64_to_cpu(iv->a) + 1); 9664470f1bSRik Snel } 9764470f1bSRik Snel 98*9ebed9d1SDavid S. Miller static inline void lrw_round(struct sinfo *s, void *dst, const void *src) 9964470f1bSRik Snel { 10064470f1bSRik Snel be128_xor(dst, &s->t, src); /* PP <- T xor P */ 10164470f1bSRik Snel s->fn(s->tfm, dst, dst); /* CC <- E(Key2,PP) */ 10264470f1bSRik Snel be128_xor(dst, dst, &s->t); /* C <- T xor CC */ 10364470f1bSRik Snel } 10464470f1bSRik Snel 10564470f1bSRik Snel /* this returns the number of consequative 1 bits starting 10664470f1bSRik Snel * from the right, get_index128(00 00 00 00 00 00 ... 00 00 10 FB) = 2 */ 10764470f1bSRik Snel static inline int get_index128(be128 *block) 10864470f1bSRik Snel { 10964470f1bSRik Snel int x; 11064470f1bSRik Snel __be32 *p = (__be32 *) block; 11164470f1bSRik Snel 11264470f1bSRik Snel for (p += 3, x = 0; x < 128; p--, x += 32) { 11364470f1bSRik Snel u32 val = be32_to_cpup(p); 11464470f1bSRik Snel 11564470f1bSRik Snel if (!~val) 11664470f1bSRik Snel continue; 11764470f1bSRik Snel 11864470f1bSRik Snel return x + ffz(val); 11964470f1bSRik Snel } 12064470f1bSRik Snel 12164470f1bSRik Snel return x; 12264470f1bSRik Snel } 12364470f1bSRik Snel 12464470f1bSRik Snel static int crypt(struct blkcipher_desc *d, 12564470f1bSRik Snel struct blkcipher_walk *w, struct priv *ctx, 12664470f1bSRik Snel void (*fn)(struct crypto_tfm *, u8 *, const u8 *)) 12764470f1bSRik Snel { 12864470f1bSRik Snel int err; 12964470f1bSRik Snel unsigned int avail; 13064470f1bSRik Snel const int bs = crypto_cipher_blocksize(ctx->child); 13164470f1bSRik Snel struct sinfo s = { 13264470f1bSRik Snel .tfm = crypto_cipher_tfm(ctx->child), 13364470f1bSRik Snel .fn = fn 13464470f1bSRik Snel }; 13564470f1bSRik Snel be128 *iv; 13664470f1bSRik Snel u8 *wsrc; 13764470f1bSRik Snel u8 *wdst; 13864470f1bSRik Snel 13964470f1bSRik Snel err = blkcipher_walk_virt(d, w); 14064470f1bSRik Snel if (!(avail = w->nbytes)) 14164470f1bSRik Snel return err; 14264470f1bSRik Snel 14364470f1bSRik Snel wsrc = w->src.virt.addr; 14464470f1bSRik Snel wdst = w->dst.virt.addr; 14564470f1bSRik Snel 14664470f1bSRik Snel /* calculate first value of T */ 14764470f1bSRik Snel iv = (be128 *)w->iv; 14864470f1bSRik Snel s.t = *iv; 14964470f1bSRik Snel 15064470f1bSRik Snel /* T <- I*Key2 */ 15164470f1bSRik Snel gf128mul_64k_bbe(&s.t, ctx->table); 15264470f1bSRik Snel 15364470f1bSRik Snel goto first; 15464470f1bSRik Snel 15564470f1bSRik Snel for (;;) { 15664470f1bSRik Snel do { 15764470f1bSRik Snel /* T <- I*Key2, using the optimization 15864470f1bSRik Snel * discussed in the specification */ 15964470f1bSRik Snel be128_xor(&s.t, &s.t, &ctx->mulinc[get_index128(iv)]); 16064470f1bSRik Snel inc(iv); 16164470f1bSRik Snel 16264470f1bSRik Snel first: 163*9ebed9d1SDavid S. Miller lrw_round(&s, wdst, wsrc); 16464470f1bSRik Snel 16564470f1bSRik Snel wsrc += bs; 16664470f1bSRik Snel wdst += bs; 16764470f1bSRik Snel } while ((avail -= bs) >= bs); 16864470f1bSRik Snel 16964470f1bSRik Snel err = blkcipher_walk_done(d, w, avail); 17064470f1bSRik Snel if (!(avail = w->nbytes)) 17164470f1bSRik Snel break; 17264470f1bSRik Snel 17364470f1bSRik Snel wsrc = w->src.virt.addr; 17464470f1bSRik Snel wdst = w->dst.virt.addr; 17564470f1bSRik Snel } 17664470f1bSRik Snel 17764470f1bSRik Snel return err; 17864470f1bSRik Snel } 17964470f1bSRik Snel 18064470f1bSRik Snel static int encrypt(struct blkcipher_desc *desc, struct scatterlist *dst, 18164470f1bSRik Snel struct scatterlist *src, unsigned int nbytes) 18264470f1bSRik Snel { 18364470f1bSRik Snel struct priv *ctx = crypto_blkcipher_ctx(desc->tfm); 18464470f1bSRik Snel struct blkcipher_walk w; 18564470f1bSRik Snel 18664470f1bSRik Snel blkcipher_walk_init(&w, dst, src, nbytes); 18764470f1bSRik Snel return crypt(desc, &w, ctx, 18864470f1bSRik Snel crypto_cipher_alg(ctx->child)->cia_encrypt); 18964470f1bSRik Snel } 19064470f1bSRik Snel 19164470f1bSRik Snel static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst, 19264470f1bSRik Snel struct scatterlist *src, unsigned int nbytes) 19364470f1bSRik Snel { 19464470f1bSRik Snel struct priv *ctx = crypto_blkcipher_ctx(desc->tfm); 19564470f1bSRik Snel struct blkcipher_walk w; 19664470f1bSRik Snel 19764470f1bSRik Snel blkcipher_walk_init(&w, dst, src, nbytes); 19864470f1bSRik Snel return crypt(desc, &w, ctx, 19964470f1bSRik Snel crypto_cipher_alg(ctx->child)->cia_decrypt); 20064470f1bSRik Snel } 20164470f1bSRik Snel 20264470f1bSRik Snel static int init_tfm(struct crypto_tfm *tfm) 20364470f1bSRik Snel { 20464470f1bSRik Snel struct crypto_instance *inst = (void *)tfm->__crt_alg; 20564470f1bSRik Snel struct crypto_spawn *spawn = crypto_instance_ctx(inst); 20664470f1bSRik Snel struct priv *ctx = crypto_tfm_ctx(tfm); 20764470f1bSRik Snel u32 *flags = &tfm->crt_flags; 20864470f1bSRik Snel 20964470f1bSRik Snel tfm = crypto_spawn_tfm(spawn); 21064470f1bSRik Snel if (IS_ERR(tfm)) 21164470f1bSRik Snel return PTR_ERR(tfm); 21264470f1bSRik Snel 21364470f1bSRik Snel if (crypto_tfm_alg_blocksize(tfm) != 16) { 21464470f1bSRik Snel *flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN; 21564470f1bSRik Snel return -EINVAL; 21664470f1bSRik Snel } 21764470f1bSRik Snel 21864470f1bSRik Snel ctx->child = crypto_cipher_cast(tfm); 21964470f1bSRik Snel return 0; 22064470f1bSRik Snel } 22164470f1bSRik Snel 22264470f1bSRik Snel static void exit_tfm(struct crypto_tfm *tfm) 22364470f1bSRik Snel { 22464470f1bSRik Snel struct priv *ctx = crypto_tfm_ctx(tfm); 22564470f1bSRik Snel if (ctx->table) 22664470f1bSRik Snel gf128mul_free_64k(ctx->table); 22764470f1bSRik Snel crypto_free_cipher(ctx->child); 22864470f1bSRik Snel } 22964470f1bSRik Snel 23064470f1bSRik Snel static struct crypto_instance *alloc(void *param, unsigned int len) 23164470f1bSRik Snel { 23264470f1bSRik Snel struct crypto_instance *inst; 23364470f1bSRik Snel struct crypto_alg *alg; 23464470f1bSRik Snel 23564470f1bSRik Snel alg = crypto_get_attr_alg(param, len, CRYPTO_ALG_TYPE_CIPHER, 23664470f1bSRik Snel CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC); 23764470f1bSRik Snel if (IS_ERR(alg)) 23864470f1bSRik Snel return ERR_PTR(PTR_ERR(alg)); 23964470f1bSRik Snel 24064470f1bSRik Snel inst = crypto_alloc_instance("lrw", alg); 24164470f1bSRik Snel if (IS_ERR(inst)) 24264470f1bSRik Snel goto out_put_alg; 24364470f1bSRik Snel 24464470f1bSRik Snel inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER; 24564470f1bSRik Snel inst->alg.cra_priority = alg->cra_priority; 24664470f1bSRik Snel inst->alg.cra_blocksize = alg->cra_blocksize; 24764470f1bSRik Snel 24864470f1bSRik Snel if (alg->cra_alignmask < 7) inst->alg.cra_alignmask = 7; 24964470f1bSRik Snel else inst->alg.cra_alignmask = alg->cra_alignmask; 25064470f1bSRik Snel inst->alg.cra_type = &crypto_blkcipher_type; 25164470f1bSRik Snel 25264470f1bSRik Snel if (!(alg->cra_blocksize % 4)) 25364470f1bSRik Snel inst->alg.cra_alignmask |= 3; 25464470f1bSRik Snel inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize; 25564470f1bSRik Snel inst->alg.cra_blkcipher.min_keysize = 25664470f1bSRik Snel alg->cra_cipher.cia_min_keysize + alg->cra_blocksize; 25764470f1bSRik Snel inst->alg.cra_blkcipher.max_keysize = 25864470f1bSRik Snel alg->cra_cipher.cia_max_keysize + alg->cra_blocksize; 25964470f1bSRik Snel 26064470f1bSRik Snel inst->alg.cra_ctxsize = sizeof(struct priv); 26164470f1bSRik Snel 26264470f1bSRik Snel inst->alg.cra_init = init_tfm; 26364470f1bSRik Snel inst->alg.cra_exit = exit_tfm; 26464470f1bSRik Snel 26564470f1bSRik Snel inst->alg.cra_blkcipher.setkey = setkey; 26664470f1bSRik Snel inst->alg.cra_blkcipher.encrypt = encrypt; 26764470f1bSRik Snel inst->alg.cra_blkcipher.decrypt = decrypt; 26864470f1bSRik Snel 26964470f1bSRik Snel out_put_alg: 27064470f1bSRik Snel crypto_mod_put(alg); 27164470f1bSRik Snel return inst; 27264470f1bSRik Snel } 27364470f1bSRik Snel 27464470f1bSRik Snel static void free(struct crypto_instance *inst) 27564470f1bSRik Snel { 27664470f1bSRik Snel crypto_drop_spawn(crypto_instance_ctx(inst)); 27764470f1bSRik Snel kfree(inst); 27864470f1bSRik Snel } 27964470f1bSRik Snel 28064470f1bSRik Snel static struct crypto_template crypto_tmpl = { 28164470f1bSRik Snel .name = "lrw", 28264470f1bSRik Snel .alloc = alloc, 28364470f1bSRik Snel .free = free, 28464470f1bSRik Snel .module = THIS_MODULE, 28564470f1bSRik Snel }; 28664470f1bSRik Snel 28764470f1bSRik Snel static int __init crypto_module_init(void) 28864470f1bSRik Snel { 28964470f1bSRik Snel return crypto_register_template(&crypto_tmpl); 29064470f1bSRik Snel } 29164470f1bSRik Snel 29264470f1bSRik Snel static void __exit crypto_module_exit(void) 29364470f1bSRik Snel { 29464470f1bSRik Snel crypto_unregister_template(&crypto_tmpl); 29564470f1bSRik Snel } 29664470f1bSRik Snel 29764470f1bSRik Snel module_init(crypto_module_init); 29864470f1bSRik Snel module_exit(crypto_module_exit); 29964470f1bSRik Snel 30064470f1bSRik Snel MODULE_LICENSE("GPL"); 30164470f1bSRik Snel MODULE_DESCRIPTION("LRW block cipher mode"); 302