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![Herbert Xu](/assets/img/avatar_default.png)
This patch adds support for using seqiv with AEAD algorithms. This is useful for those AEAD algorithms that performs authentication before encryption because the IV generated by the underlying encryption algorithm won't be available for authentication. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
345 lines
8.2 KiB
C
345 lines
8.2 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 <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 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 complete;
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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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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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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 complete;
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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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complete = 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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complete = 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, complete, 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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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_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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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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get_random_bytes(ctx->salt, crypto_aead_ivsize(geniv));
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unlock:
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spin_unlock_bh(&ctx->lock);
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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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err = PTR_ERR(algt);
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if (IS_ERR(algt))
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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 out;
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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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}
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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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}
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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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