365 lines
8.5 KiB
C
365 lines
8.5 KiB
C
/*
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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/aead.h>
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#include <crypto/internal/skcipher.h>
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#include <crypto/rng.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/slab.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 void seqiv_aead_complete2(struct aead_givcrypt_request *req, int err)
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{
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struct aead_request *subreq = aead_givcrypt_reqctx(req);
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struct crypto_aead *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 = aead_givcrypt_reqtfm(req);
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memcpy(req->areq.iv, subreq->iv, crypto_aead_ivsize(geniv));
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out:
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kfree(subreq->iv);
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}
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static void seqiv_aead_complete(struct crypto_async_request *base, int err)
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{
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struct aead_givcrypt_request *req = base->data;
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seqiv_aead_complete2(req, err);
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aead_givcrypt_complete(req, err);
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}
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static void seqiv_geniv(struct seqiv_ctx *ctx, u8 *info, u64 seq,
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unsigned int ivsize)
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{
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unsigned int 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(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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}
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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 compl;
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void *data;
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u8 *info;
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unsigned int ivsize;
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int err;
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ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
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compl = 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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compl = 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, compl,
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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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seqiv_geniv(ctx, info, req->seq, 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_aead_givencrypt(struct aead_givcrypt_request *req)
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{
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struct crypto_aead *geniv = aead_givcrypt_reqtfm(req);
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struct seqiv_ctx *ctx = crypto_aead_ctx(geniv);
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struct aead_request *areq = &req->areq;
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struct aead_request *subreq = aead_givcrypt_reqctx(req);
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crypto_completion_t compl;
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void *data;
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u8 *info;
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unsigned int ivsize;
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int err;
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aead_request_set_tfm(subreq, aead_geniv_base(geniv));
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compl = areq->base.complete;
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data = areq->base.data;
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info = areq->iv;
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ivsize = crypto_aead_ivsize(geniv);
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if (unlikely(!IS_ALIGNED((unsigned long)info,
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crypto_aead_alignmask(geniv) + 1))) {
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info = kmalloc(ivsize, areq->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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compl = seqiv_aead_complete;
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data = req;
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}
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aead_request_set_callback(subreq, areq->base.flags, compl, data);
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aead_request_set_crypt(subreq, areq->src, areq->dst, areq->cryptlen,
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info);
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aead_request_set_assoc(subreq, areq->assoc, areq->assoclen);
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seqiv_geniv(ctx, info, req->seq, ivsize);
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memcpy(req->giv, info, ivsize);
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err = crypto_aead_encrypt(subreq);
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if (unlikely(info != areq->iv))
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seqiv_aead_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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int err = 0;
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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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err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
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crypto_ablkcipher_ivsize(geniv));
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unlock:
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spin_unlock_bh(&ctx->lock);
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if (err)
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return err;
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return seqiv_givencrypt(req);
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}
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static int seqiv_aead_givencrypt_first(struct aead_givcrypt_request *req)
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{
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struct crypto_aead *geniv = aead_givcrypt_reqtfm(req);
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struct seqiv_ctx *ctx = crypto_aead_ctx(geniv);
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int err = 0;
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spin_lock_bh(&ctx->lock);
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if (crypto_aead_crt(geniv)->givencrypt != seqiv_aead_givencrypt_first)
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goto unlock;
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crypto_aead_crt(geniv)->givencrypt = seqiv_aead_givencrypt;
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err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
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crypto_aead_ivsize(geniv));
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unlock:
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spin_unlock_bh(&ctx->lock);
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if (err)
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return err;
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return seqiv_aead_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 int seqiv_aead_init(struct crypto_tfm *tfm)
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{
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struct crypto_aead *geniv = __crypto_aead_cast(tfm);
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struct seqiv_ctx *ctx = crypto_aead_ctx(geniv);
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spin_lock_init(&ctx->lock);
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tfm->crt_aead.reqsize = sizeof(struct aead_request);
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return aead_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_ablkcipher_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_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_instance *seqiv_aead_alloc(struct rtattr **tb)
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{
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struct crypto_instance *inst;
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inst = aead_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_aead.givencrypt = seqiv_aead_givencrypt_first;
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inst->alg.cra_init = seqiv_aead_init;
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inst->alg.cra_exit = aead_geniv_exit;
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inst->alg.cra_ctxsize = inst->alg.cra_aead.ivsize;
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out:
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return inst;
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}
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static struct crypto_instance *seqiv_alloc(struct rtattr **tb)
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{
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struct crypto_attr_type *algt;
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struct crypto_instance *inst;
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int err;
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algt = crypto_get_attr_type(tb);
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if (IS_ERR(algt))
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return ERR_CAST(algt);
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err = crypto_get_default_rng();
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if (err)
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return ERR_PTR(err);
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if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
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inst = seqiv_ablkcipher_alloc(tb);
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else
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inst = seqiv_aead_alloc(tb);
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if (IS_ERR(inst))
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goto put_rng;
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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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out:
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return inst;
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put_rng:
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crypto_put_default_rng();
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goto out;
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}
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static void seqiv_free(struct crypto_instance *inst)
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{
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if ((inst->alg.cra_flags ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
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skcipher_geniv_free(inst);
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else
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aead_geniv_free(inst);
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crypto_put_default_rng();
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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 = seqiv_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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