diff options
Diffstat (limited to 'crypto/lrw.c')
| -rw-r--r-- | crypto/lrw.c | 106 |
1 files changed, 86 insertions, 20 deletions
diff --git a/crypto/lrw.c b/crypto/lrw.c index 91c17fa..ba42acc 100644 --- a/crypto/lrw.c +++ b/crypto/lrw.c @@ -3,7 +3,7 @@ * * Copyright (c) 2006 Rik Snel <rsnel@cube.dyndns.org> * - * Based om ecb.c + * Based on ecb.c * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au> * * This program is free software; you can redistribute it and/or modify it @@ -16,6 +16,7 @@ * http://www.mail-archive.com/stds-p1619@listserv.ieee.org/msg00173.html * * The test vectors are included in the testing module tcrypt.[ch] */ + #include <crypto/algapi.h> #include <linux/err.h> #include <linux/init.h> @@ -26,23 +27,7 @@ #include <crypto/b128ops.h> #include <crypto/gf128mul.h> - -#define LRW_BLOCK_SIZE 16 - -struct lrw_table_ctx { - /* 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 */ - be128 mulinc[128]; -}; +#include <crypto/lrw.h> struct priv { struct crypto_cipher *child; @@ -60,7 +45,7 @@ static inline void setbit128_bbe(void *b, int bit) ), b); } -static int lrw_init_table(struct lrw_table_ctx *ctx, const u8 *tweak) +int lrw_init_table(struct lrw_table_ctx *ctx, const u8 *tweak) { be128 tmp = { 0 }; int i; @@ -82,12 +67,14 @@ static int lrw_init_table(struct lrw_table_ctx *ctx, const u8 *tweak) return 0; } +EXPORT_SYMBOL_GPL(lrw_init_table); -static void lrw_free_table(struct lrw_table_ctx *ctx) +void lrw_free_table(struct lrw_table_ctx *ctx) { if (ctx->table) gf128mul_free_64k(ctx->table); } +EXPORT_SYMBOL_GPL(lrw_free_table); static int setkey(struct crypto_tfm *parent, const u8 *key, unsigned int keylen) @@ -227,6 +214,85 @@ static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst, crypto_cipher_alg(ctx->child)->cia_decrypt); } +int lrw_crypt(struct blkcipher_desc *desc, struct scatterlist *sdst, + struct scatterlist *ssrc, unsigned int nbytes, + struct lrw_crypt_req *req) +{ + const unsigned int bsize = LRW_BLOCK_SIZE; + const unsigned int max_blks = req->tbuflen / bsize; + struct lrw_table_ctx *ctx = req->table_ctx; + struct blkcipher_walk walk; + unsigned int nblocks; + be128 *iv, *src, *dst, *t; + be128 *t_buf = req->tbuf; + int err, i; + + BUG_ON(max_blks < 1); + + blkcipher_walk_init(&walk, sdst, ssrc, nbytes); + + err = blkcipher_walk_virt(desc, &walk); + nbytes = walk.nbytes; + if (!nbytes) + return err; + + nblocks = min(walk.nbytes / bsize, max_blks); + src = (be128 *)walk.src.virt.addr; + dst = (be128 *)walk.dst.virt.addr; + + /* calculate first value of T */ + iv = (be128 *)walk.iv; + t_buf[0] = *iv; + + /* T <- I*Key2 */ + gf128mul_64k_bbe(&t_buf[0], ctx->table); + + i = 0; + goto first; + + for (;;) { + do { + for (i = 0; i < nblocks; i++) { + /* T <- I*Key2, using the optimization + * discussed in the specification */ + be128_xor(&t_buf[i], t, + &ctx->mulinc[get_index128(iv)]); + inc(iv); +first: + t = &t_buf[i]; + + /* PP <- T xor P */ + be128_xor(dst + i, t, src + i); + } + + /* CC <- E(Key2,PP) */ + req->crypt_fn(req->crypt_ctx, (u8 *)dst, + nblocks * bsize); + + /* C <- T xor CC */ + for (i = 0; i < nblocks; i++) + be128_xor(dst + i, dst + i, &t_buf[i]); + + src += nblocks; + dst += nblocks; + nbytes -= nblocks * bsize; + nblocks = min(nbytes / bsize, max_blks); + } while (nblocks > 0); + + err = blkcipher_walk_done(desc, &walk, nbytes); + nbytes = walk.nbytes; + if (!nbytes) + break; + + nblocks = min(nbytes / bsize, max_blks); + src = (be128 *)walk.src.virt.addr; + dst = (be128 *)walk.dst.virt.addr; + } + + return err; +} +EXPORT_SYMBOL_GPL(lrw_crypt); + static int init_tfm(struct crypto_tfm *tfm) { struct crypto_cipher *cipher; |
