[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 <herbert@gondor.apana.org.au>hifive-unleashed-5.1
Herbert Xu
parent
45d44eb56a
commit
0a270321db
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@ -32,6 +32,14 @@ config CRYPTO_BLKCIPHER
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tristate
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select CRYPTO_ALGAPI
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config CRYPTO_SEQIV
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tristate "Sequence Number IV Generator"
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select CRYPTO_BLKCIPHER
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help
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This IV generator generates an IV based on a sequence number by
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xoring it with a salt. This algorithm is mainly useful for CTR
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and similar modes.
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config CRYPTO_HASH
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tristate
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select CRYPTO_ALGAPI
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@ -197,6 +205,7 @@ config CRYPTO_XTS
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config CRYPTO_CTR
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tristate "CTR support"
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select CRYPTO_BLKCIPHER
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select CRYPTO_SEQIV
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select CRYPTO_MANAGER
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help
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CTR: Counter mode
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@ -15,6 +15,7 @@ crypto_blkcipher-objs += blkcipher.o
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obj-$(CONFIG_CRYPTO_BLKCIPHER) += crypto_blkcipher.o
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obj-$(CONFIG_CRYPTO_BLKCIPHER) += chainiv.o
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obj-$(CONFIG_CRYPTO_BLKCIPHER) += eseqiv.o
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obj-$(CONFIG_CRYPTO_SEQIV) += seqiv.o
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crypto_hash-objs := hash.o
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obj-$(CONFIG_CRYPTO_HASH) += crypto_hash.o
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@ -361,6 +361,8 @@ static struct crypto_instance *crypto_rfc3686_alloc(struct rtattr **tb)
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inst->alg.cra_blkcipher.max_keysize = alg->cra_blkcipher.max_keysize
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+ CTR_RFC3686_NONCE_SIZE;
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inst->alg.cra_blkcipher.geniv = "seqiv";
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inst->alg.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);
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inst->alg.cra_init = crypto_rfc3686_init_tfm;
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@ -0,0 +1,186 @@
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/*
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* seqiv: Sequence Number IV Generator
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*
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* This generator generates an IV based on a sequence number by xoring it
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* with a salt. This algorithm is mainly useful for CTR and similar modes.
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*
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* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <crypto/internal/skcipher.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/random.h>
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#include <linux/spinlock.h>
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#include <linux/string.h>
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struct seqiv_ctx {
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spinlock_t lock;
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u8 salt[] __attribute__ ((aligned(__alignof__(u32))));
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};
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static void seqiv_complete2(struct skcipher_givcrypt_request *req, int err)
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{
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struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
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struct crypto_ablkcipher *geniv;
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if (err == -EINPROGRESS)
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return;
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if (err)
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goto out;
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geniv = skcipher_givcrypt_reqtfm(req);
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memcpy(req->creq.info, subreq->info, crypto_ablkcipher_ivsize(geniv));
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out:
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kfree(subreq->info);
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}
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static void seqiv_complete(struct crypto_async_request *base, int err)
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{
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struct skcipher_givcrypt_request *req = base->data;
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seqiv_complete2(req, err);
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skcipher_givcrypt_complete(req, err);
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}
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static int seqiv_givencrypt(struct skcipher_givcrypt_request *req)
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{
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struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
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struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
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struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
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crypto_completion_t complete;
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void *data;
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u8 *info;
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__be64 seq;
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unsigned int ivsize;
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unsigned int len;
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int err;
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ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
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complete = req->creq.base.complete;
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data = req->creq.base.data;
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info = req->creq.info;
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ivsize = crypto_ablkcipher_ivsize(geniv);
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if (unlikely(!IS_ALIGNED((unsigned long)info,
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crypto_ablkcipher_alignmask(geniv) + 1))) {
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info = kmalloc(ivsize, req->creq.base.flags &
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CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
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GFP_ATOMIC);
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if (!info)
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return -ENOMEM;
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complete = seqiv_complete;
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data = req;
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}
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ablkcipher_request_set_callback(subreq, req->creq.base.flags, complete,
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data);
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ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
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req->creq.nbytes, info);
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len = ivsize;
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if (ivsize > sizeof(u64)) {
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memset(info, 0, ivsize - sizeof(u64));
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len = sizeof(u64);
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}
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seq = cpu_to_be64(req->seq);
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memcpy(info + ivsize - len, &seq, len);
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crypto_xor(info, ctx->salt, ivsize);
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memcpy(req->giv, info, ivsize);
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err = crypto_ablkcipher_encrypt(subreq);
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if (unlikely(info != req->creq.info))
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seqiv_complete2(req, err);
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return err;
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}
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static int seqiv_givencrypt_first(struct skcipher_givcrypt_request *req)
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{
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struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
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struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
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spin_lock_bh(&ctx->lock);
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if (crypto_ablkcipher_crt(geniv)->givencrypt != seqiv_givencrypt_first)
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goto unlock;
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crypto_ablkcipher_crt(geniv)->givencrypt = seqiv_givencrypt;
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get_random_bytes(ctx->salt, crypto_ablkcipher_ivsize(geniv));
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unlock:
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spin_unlock_bh(&ctx->lock);
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return seqiv_givencrypt(req);
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}
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static int seqiv_init(struct crypto_tfm *tfm)
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{
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struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm);
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struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
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spin_lock_init(&ctx->lock);
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tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request);
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return skcipher_geniv_init(tfm);
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}
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static struct crypto_template seqiv_tmpl;
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static struct crypto_instance *seqiv_alloc(struct rtattr **tb)
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{
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struct crypto_instance *inst;
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inst = skcipher_geniv_alloc(&seqiv_tmpl, tb, 0, 0);
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if (IS_ERR(inst))
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goto out;
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inst->alg.cra_ablkcipher.givencrypt = seqiv_givencrypt_first;
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inst->alg.cra_init = seqiv_init;
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inst->alg.cra_exit = skcipher_geniv_exit;
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inst->alg.cra_alignmask |= __alignof__(u32) - 1;
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inst->alg.cra_ctxsize = sizeof(struct seqiv_ctx);
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inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize;
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out:
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return inst;
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}
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static struct crypto_template seqiv_tmpl = {
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.name = "seqiv",
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.alloc = seqiv_alloc,
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.free = skcipher_geniv_free,
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.module = THIS_MODULE,
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};
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static int __init seqiv_module_init(void)
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{
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return crypto_register_template(&seqiv_tmpl);
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}
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static void __exit seqiv_module_exit(void)
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{
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crypto_unregister_template(&seqiv_tmpl);
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}
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module_init(seqiv_module_init);
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module_exit(seqiv_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Sequence Number IV Generator");
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