Main module, this implements the Liskov Rivest Wagner block cipher mode in the new blockcipher API. The implementation is based on ecb.c. The first iteration of the blockcipher_walk loop is unrolled to give the first narrow block special treatment.
The LRW-32-AES specification I used can be found at: http://grouper.ieee.org/groups/1619/email/pdf00017.pdf It implements the optimization specified as optional in the specification, and in addition it uses optimized multiplication routines from gf128mul.c. Since gf128mul.[ch] is not tested on bigendian, this cipher mode may currently fail badly on bigendian machines. Signed-off-by: Rik Snel <[EMAIL PROTECTED]> --- crypto/Kconfig | 13 ++ crypto/Makefile | 1 crypto/lrw.c | 297 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 311 insertions(+), 0 deletions(-) diff --git a/crypto/Kconfig b/crypto/Kconfig index 6b23c20..dfdfe08 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -156,6 +156,19 @@ config CRYPTO_CBC CBC: Cipher Block Chaining mode This block cipher algorithm is required for IPSec. +config CRYPTO_LRW + tristate "LRW support (EXPERIMENTAL)" + depends on EXPERIMENTAL + select CRYPTO_BLKCIPHER + select CRYPTO_GF128MUL + default n + help + LRW: Liskov Rivest Wagner, a tweakable, non malleable, non movable + narrow block cipher mode. Use it with cipher specification string + aes-lrw-benbi, the key must be 256, 320 or 384. The first 128, 192 + or 256 bits in the key are used for AES and the rest is used to tie + each cipher block to its logical position. + config CRYPTO_DES tristate "DES and Triple DES EDE cipher algorithms" select CRYPTO_ALGAPI diff --git a/crypto/Makefile b/crypto/Makefile index bf0406b..e2e57be 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -26,6 +26,7 @@ obj-$(CONFIG_CRYPTO_TGR192) += tgr192.o obj-$(CONFIG_CRYPTO_GF128MUL) += gf128mul.o obj-$(CONFIG_CRYPTO_ECB) += ecb.o obj-$(CONFIG_CRYPTO_CBC) += cbc.o +obj-$(CONFIG_CRYPTO_LRW) += lrw.o obj-$(CONFIG_CRYPTO_DES) += des.o obj-$(CONFIG_CRYPTO_BLOWFISH) += blowfish.o obj-$(CONFIG_CRYPTO_TWOFISH) += twofish.o diff --git a/crypto/lrw.c b/crypto/lrw.c new file mode 100644 index 0000000..9c7324c --- /dev/null +++ b/crypto/lrw.c @@ -0,0 +1,297 @@ +/* LRW: as defined by Cyril Guyot in + * http://grouper.ieee.org/groups/1619/email/pdf00017.pdf + * + * Copyright (c) 2006 Rik Snel <[EMAIL PROTECTED]> + * + * Based om ecb.c + * Copyright (c) 2006 Herbert Xu <[EMAIL PROTECTED]> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + */ + +/* This implementation is checked against the test vectors in the above + * document and by a test vector provided by Ken Buchanan at + * http://www.mail-archive.com/stds-p1619@listserv.ieee.org/msg00173.html + * + * The vectors can be found in Documentation/crypto they are in the form + * of a script and can therefore easily be checked, just run lrw-32-aes + * with sufficient permissions after reading it and also testvector.fun */ +#include <crypto/algapi.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/scatterlist.h> +#include <linux/slab.h> + +#include "b128ops.h" +#include "gf128mul.h" + +struct priv { + struct crypto_cipher *child; + /* optimizes multiplying a random (non incrementing, as at the + * start of a new sector) value with key2, we could also have + * used 4k optimization tables or no optimization at all. In the + * latter case we would have to store key2 here */ + struct gf128mul_64k table; + /* stores: + * key2*{ 0,0,...0,0,0,0,1 }, key2*{ 0,0,...0,0,0,1,1 }, + * key2*{ 0,0,...0,0,1,1,1 }, key2*{ 0,0,...0,1,1,1,1 } + * key2*{ 0,0,...1,1,1,1,1 }, etc + * needed for optimized multiplication of incrementing values + * with key2 */ + u64 mulinc[128][GF128MUL_BYTES >> 3]; +}; + +static inline void setbit128(void *b, int bit) +{ + int index = 15 - bit/8; + ((u8*)b)[index] |= 1<<(bit%8); +} + +static int setkey(struct crypto_tfm *parent, const u8 *key, + unsigned int keylen) +{ + struct priv *ctx = crypto_tfm_ctx(parent); + struct crypto_cipher *child = ctx->child; + int err, i; + u64 tmp[2] = { 0, }, scratch[2]; + int bsize = crypto_cipher_blocksize(child); + + crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK); + crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) & + CRYPTO_TFM_REQ_MASK); + if ((err = crypto_cipher_setkey(child, key, keylen - bsize))) + return err; + crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) & + CRYPTO_TFM_RES_MASK); + + + /* initialize multiplication table for Key2 */ + gf128mul_init_64k_bbe(&ctx->table, (u64*)(key + keylen - bsize)); + + /* initialize optimization table */ + for (i = 0; i < 128; i++) { + setbit128(tmp, i); + b128ops_mov(ctx->mulinc[i], tmp); + gf128mul_64k_bbe(ctx->mulinc[i], &ctx->table, scratch); + } + + return 0; +} + +struct sinfo { + u64 b1[2], b2[2]; + struct crypto_tfm *tfm; + void (*fn)(struct crypto_tfm*, u8*, const u8*); +}; + +static inline void inc(u64 *iv) +{ + if (!(iv[1] = cpu_to_be64(be64_to_cpu(iv[1]) + 1))) + iv[0] = cpu_to_be64(be64_to_cpu(iv[0]) + 1); +} + +static inline void round(struct sinfo *s, u8 *dst, const u8 *src) +{ + b128ops_xor(s->b2, src); /* PP <- T xor P */ + s->fn(s->tfm, dst, (u8*)s->b2); /* CC <- E(Key2,PP) */ + b128ops_xor(dst, s->b1); /* C <- T xor CC */ +} + +/* this returns the number of consequative 1 bits + * starting from the right in i */ +static inline int get_index8(u8 i) +{ + int j = 1; + + if (i&1) { + while ((i >>= 1)&1) j++; + return j; + } + + return 0; +} + +/* this returns the number of consequative 1 bits starting + * from the right, get_index128(00 00 00 00 00 00 ... 00 00 10 FB) = 2 */ +static inline int get_index128(u8 *block) +{ + int inc, ret = 0, len = 16; + while ((inc = get_index8(block[--len])) == 8) ret += 8; + return ret + inc; +} + +static int crypt(struct blkcipher_desc *d, + struct scatterlist *dst, + struct scatterlist *src, + unsigned int nbytes, struct priv *ctx, + void (*fn)(struct crypto_tfm*, u8*, const u8*)) +{ + struct blkcipher_walk w; + int err; + unsigned int avail; + const int bs = crypto_cipher_blocksize(ctx->child); + u8 *wsrc, *wdst; + struct sinfo s = { + .tfm = crypto_cipher_tfm(ctx->child), + .fn = fn + }; + + blkcipher_walk_init(&w, dst, src, nbytes); + + /* start of the loop unrolled to be able to + * handle the first block diffently from the others */ + if ((err = blkcipher_walk_virt(d, &w))) return err; + + wsrc = w.src.virt.addr; + wdst = w.dst.virt.addr; + + /* calculate first value of T */ + b128ops_mov(s.b1, w.iv); + gf128mul_64k_bbe(s.b1, &ctx->table, s.b2); /* T <- I*Key2 */ + + round(&s, wdst, wsrc); + + while ((avail = w.nbytes)) { + while ((avail -= bs) >= bs) { + wsrc += bs; + wdst += bs; + + /* old T is available in s.b1; new one + * must be made available in b1 and b2 */ + + /* T <- I*Key2, using the optimization + * discussed in the specification */ + b128ops_xor(s.b1, ctx->mulinc[get_index128(w.iv)]); + inc((u64*)w.iv); + b128ops_mov(s.b2, s.b1); + + round(&s, wdst, wsrc); + } + + if ((err = blkcipher_walk_done(d, &w, avail))) return err; + + wsrc = w.src.virt.addr; + wdst = w.dst.virt.addr; + } + return err; +} + +static int encrypt(struct blkcipher_desc *desc, struct scatterlist *dst, + struct scatterlist *src, unsigned int nbytes) +{ + struct priv *ctx = crypto_blkcipher_ctx(desc->tfm); + return crypt(desc, dst, src, nbytes, ctx, + crypto_cipher_alg(ctx->child)->cia_encrypt); +} + +static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst, + struct scatterlist *src, unsigned int nbytes) +{ + struct priv *ctx = crypto_blkcipher_ctx(desc->tfm); + return crypt(desc, dst, src, nbytes, ctx, + crypto_cipher_alg(ctx->child)->cia_decrypt); +} + +static int init_tfm(struct crypto_tfm *tfm) +{ + struct crypto_instance *inst = (void *)tfm->__crt_alg; + struct crypto_spawn *spawn = crypto_instance_ctx(inst); + struct priv *ctx = crypto_tfm_ctx(tfm); + u32 *flags = &tfm->crt_flags; + + tfm = crypto_spawn_tfm(spawn); + if (IS_ERR(tfm)) + return PTR_ERR(tfm); + + if (crypto_tfm_alg_blocksize(tfm) != 16) { + *flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN; + return -EINVAL; + } + + ctx->child = crypto_cipher_cast(tfm); + return 0; +} + +static void exit_tfm(struct crypto_tfm *tfm) +{ + struct priv *ctx = crypto_tfm_ctx(tfm); + crypto_free_cipher(ctx->child); +} + +static struct crypto_instance *alloc(void *param, unsigned int len) +{ + struct crypto_instance *inst; + struct crypto_alg *alg; + + alg = crypto_get_attr_alg(param, len, CRYPTO_ALG_TYPE_CIPHER, + CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC); + if (IS_ERR(alg)) + return ERR_PTR(PTR_ERR(alg)); + + inst = crypto_alloc_instance("lrw", alg); + if (IS_ERR(inst)) + goto out_put_alg; + + inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER; + inst->alg.cra_priority = alg->cra_priority; + inst->alg.cra_blocksize = alg->cra_blocksize; + + if (alg->cra_alignmask < 7) inst->alg.cra_alignmask = 7; + else inst->alg.cra_alignmask = alg->cra_alignmask; + inst->alg.cra_type = &crypto_blkcipher_type; + + if (!(alg->cra_blocksize % 4)) + inst->alg.cra_alignmask |= 3; + inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize; + inst->alg.cra_blkcipher.min_keysize = + alg->cra_cipher.cia_min_keysize + alg->cra_blocksize; + inst->alg.cra_blkcipher.max_keysize = + alg->cra_cipher.cia_max_keysize + alg->cra_blocksize; + + inst->alg.cra_ctxsize = sizeof(struct priv); + + inst->alg.cra_init = init_tfm; + inst->alg.cra_exit = exit_tfm; + + inst->alg.cra_blkcipher.setkey = setkey; + inst->alg.cra_blkcipher.encrypt = encrypt; + inst->alg.cra_blkcipher.decrypt = decrypt; + +out_put_alg: + crypto_mod_put(alg); + return inst; +} + +static void free(struct crypto_instance *inst) +{ + crypto_drop_spawn(crypto_instance_ctx(inst)); + kfree(inst); +} + +static struct crypto_template crypto_tmpl = { + .name = "lrw", + .alloc = alloc, + .free = free, + .module = THIS_MODULE, +}; + +static int __init crypto_module_init(void) +{ + return crypto_register_template(&crypto_tmpl); +} + +static void __exit crypto_module_exit(void) +{ + crypto_unregister_template(&crypto_tmpl); +} + +module_init(crypto_module_init); +module_exit(crypto_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("LRW block cipher mode"); -- 1.4.1.1 - To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
