From: Herbert Xu Subject: [PATCH 9/11] [CRYPTO] seqiv: Add Sequence Number IV Generator Date: Thu, 22 Nov 2007 16:48:47 +0800 Message-ID: References: <20071122084758.GA7536@gondor.apana.org.au> To: Linux Crypto Mailing List Return-path: Received: from rhun.apana.org.au ([64.62.148.172]:1121 "EHLO arnor.apana.org.au" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751778AbXKVJCr (ORCPT ); Thu, 22 Nov 2007 04:02:47 -0500 Received: from gondolin.me.apana.org.au ([192.168.0.6] ident=mail) by arnor.apana.org.au with esmtp (Exim 4.50 #1 (Debian)) id 1Iv7ju-0008DQ-C9 for ; Thu, 22 Nov 2007 19:48:51 +1100 Sender: linux-crypto-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org [CRYPTO] seqiv: Add Sequence Number IV Generator This generator generates an IV based on a sequence number by xoring it with a salt. This algorithm is mainly useful for CTR and similar modes. This patch also sets it as the default IV generator for ctr. Signed-off-by: Herbert Xu --- crypto/Kconfig | 5 + crypto/Makefile | 1 crypto/ctr.c | 2 crypto/seqiv.c | 202 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 210 insertions(+) diff --git a/crypto/Kconfig b/crypto/Kconfig index 0528702..d2e1ae6 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -32,6 +32,10 @@ config CRYPTO_BLKCIPHER tristate select CRYPTO_ALGAPI +config CRYPTO_SEQIV + tristate + select CRYPTO_BLKCIPHER + config CRYPTO_HASH tristate select CRYPTO_ALGAPI @@ -197,6 +201,7 @@ config CRYPTO_XTS config CRYPTO_CTR tristate "CTR support" select CRYPTO_BLKCIPHER + select CRYPTO_SEQIV select CRYPTO_MANAGER help CTR: Counter mode diff --git a/crypto/Makefile b/crypto/Makefile index 4d50435..2770ad8 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -15,6 +15,7 @@ crypto_blkcipher-objs += blkcipher.o obj-$(CONFIG_CRYPTO_BLKCIPHER) += crypto_blkcipher.o obj-$(CONFIG_CRYPTO_BLKCIPHER) += chainiv.o obj-$(CONFIG_CRYPTO_BLKCIPHER) += eseqiv.o +obj-$(CONFIG_CRYPTO_SEQIV) += seqiv.o crypto_hash-objs := hash.o obj-$(CONFIG_CRYPTO_HASH) += crypto_hash.o diff --git a/crypto/ctr.c b/crypto/ctr.c index b816e95..47e044a 100644 --- a/crypto/ctr.c +++ b/crypto/ctr.c @@ -286,6 +286,8 @@ static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb) inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize + noncesize; + memcpy(inst->alg.cra_blkcipher.geniv, "seqiv", sizeof("seqiv")); + inst->alg.cra_ctxsize = sizeof(struct crypto_ctr_ctx); inst->alg.cra_init = crypto_ctr_init_tfm; diff --git a/crypto/seqiv.c b/crypto/seqiv.c new file mode 100644 index 0000000..77277d2 --- /dev/null +++ b/crypto/seqiv.c @@ -0,0 +1,202 @@ +/* + * seqiv: Sequence Number IV Generator + * + * This generator generates an IV based on a sequence number by xoring it + * with a salt. This algorithm is mainly useful for CTR and similar modes. + * + * Copyright (c) 2007 Herbert Xu + * + * 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. + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +struct seqiv_ctx { + struct crypto_ablkcipher *cipher; + spinlock_t lock; + u8 salt[] __attribute__ ((aligned(__alignof__(u32)))); +}; + +static void seqiv_complete2(struct ablkcipher_request *req, int err) +{ + struct ablkcipher_request *subreq = ablkcipher_request_ctx(req); + struct crypto_ablkcipher *geniv; + + if (err == -EINPROGRESS) + return; + + if (err) + goto out; + + geniv = crypto_ablkcipher_reqtfm(req); + memcpy(req->info, subreq->info, crypto_ablkcipher_ivsize(geniv)); + +out: + kfree(subreq->info); +} + +static void seqiv_complete(struct crypto_async_request *base, int err) +{ + struct ablkcipher_request *req = base->data; + + seqiv_complete2(req, err); + ablkcipher_request_complete(req, err); +} + +static int seqiv_givcrypt(struct ablkcipher_request *req) +{ + struct crypto_ablkcipher *geniv = crypto_ablkcipher_reqtfm(req); + struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv); + struct ablkcipher_request *subreq = ablkcipher_request_ctx(req); + crypto_completion_t complete; + void *data; + u8 *info; + __be64 seq; + unsigned int ivsize; + unsigned int len; + int err; + + ablkcipher_request_set_tfm(subreq, ctx->cipher); + + complete = req->base.complete; + data = req->base.data; + info = req->info; + + ivsize = crypto_ablkcipher_ivsize(geniv); + + if (!IS_ALIGNED((unsigned long)info, + crypto_ablkcipher_alignmask(geniv) + 1)) { + info = kmalloc(ivsize, req->base.flags & + CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL: + GFP_ATOMIC); + if (!info) + return -ENOMEM; + + complete = seqiv_complete; + data = req; + } + + ablkcipher_request_set_callback(subreq, req->base.flags, complete, + data); + ablkcipher_request_set_crypt(subreq, req->src, req->dst, req->nbytes, + info); + + len = ivsize; + if (ivsize > sizeof(u64)) { + memset(info, 0, ivsize - sizeof(u64)); + len = sizeof(u64); + } + seq = cpu_to_be64(req->seq); + memcpy(info + ivsize - len, &seq, len); + crypto_xor(info, ctx->salt, ivsize); + + memcpy(req->giv, info, ivsize); + + err = crypto_ablkcipher_encrypt(subreq); + if (info != req->info) + seqiv_complete2(req, err); + return err; +} + +static int seqiv_givcrypt_first(struct ablkcipher_request *req) +{ + struct crypto_ablkcipher *geniv = crypto_ablkcipher_reqtfm(req); + struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv); + struct crypto_ablkcipher *cipher = ctx->cipher; + + spin_lock_bh(&ctx->lock); + if (crypto_ablkcipher_crt(cipher)->givcrypt != seqiv_givcrypt_first) + goto unlock; + + crypto_ablkcipher_crt(cipher)->givcrypt = seqiv_givcrypt; + get_random_bytes(ctx->salt, crypto_ablkcipher_ivsize(geniv)); + +unlock: + spin_unlock_bh(&ctx->lock); + + return seqiv_givcrypt(req); +} + +static int seqiv_init(struct crypto_tfm *tfm) +{ + struct crypto_instance *inst = (void *)tfm->__crt_alg; + struct crypto_spawn *spawn = crypto_instance_ctx(inst); + struct seqiv_ctx *ctx = crypto_tfm_ctx(tfm); + struct crypto_ablkcipher *cipher; + + cipher = crypto_spawn_nivcipher(spawn); + if (IS_ERR(cipher)) + return PTR_ERR(cipher); + + ctx->cipher = cipher; + spin_lock_init(&ctx->lock); + + tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request) + + crypto_ablkcipher_reqsize(cipher); + + return 0; +} + +static void seqiv_exit(struct crypto_tfm *tfm) +{ + struct seqiv_ctx *ctx = crypto_tfm_ctx(tfm); + crypto_free_ablkcipher(ctx->cipher); +} + +static struct crypto_template crypto_seqiv_tmpl; + +static struct crypto_instance *seqiv_alloc(struct rtattr **tb) +{ + struct crypto_instance *inst; + + inst = givcipher_alloc_inst(&crypto_seqiv_tmpl, tb, 0, 0); + if (IS_ERR(inst)) + goto out; + + inst->alg.cra_ablkcipher.givcrypt = seqiv_givcrypt_first; + + inst->alg.cra_init = seqiv_init; + inst->alg.cra_exit = seqiv_exit; + + inst->alg.cra_alignmask |= __alignof__(u32) - 1; + + inst->alg.cra_ctxsize = sizeof(struct seqiv_ctx); + inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize; + +out: + return inst; +} + +static struct crypto_template seqiv_tmpl = { + .name = "seqiv", + .alloc = seqiv_alloc, + .free = givcipher_free_inst, + .module = THIS_MODULE, +}; + +static int __init seqiv_module_init(void) +{ + return crypto_register_template(&seqiv_tmpl); +} + +static void __exit seqiv_module_exit(void) +{ + crypto_unregister_template(&seqiv_tmpl); +} + +module_init(seqiv_module_init); +module_exit(seqiv_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Sequence Number IV Generator");