363 lines
8.6 KiB
C
Executable File
363 lines
8.6 KiB
C
Executable File
/*
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* chainiv: Chain IV Generator
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*
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* Generate IVs simply be using the last block of the previous encryption.
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* This is mainly useful for CBC with a synchronous algorithm.
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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 <crypto/rng.h>
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#include <crypto/crypto_wq.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/spinlock.h>
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#include <linux/string.h>
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#include <linux/workqueue.h>
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enum {
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CHAINIV_STATE_INUSE = 0,
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};
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struct chainiv_ctx {
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spinlock_t lock;
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char iv[];
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};
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struct async_chainiv_ctx {
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unsigned long state;
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spinlock_t lock;
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int err;
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struct crypto_queue queue;
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struct work_struct postponed;
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char iv[];
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};
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static int chainiv_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 chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
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struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
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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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ablkcipher_request_set_callback(subreq, req->creq.base.flags &
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~CRYPTO_TFM_REQ_MAY_SLEEP,
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req->creq.base.complete,
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req->creq.base.data);
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ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
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req->creq.nbytes, req->creq.info);
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spin_lock_bh(&ctx->lock);
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ivsize = crypto_ablkcipher_ivsize(geniv);
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memcpy(req->giv, ctx->iv, ivsize);
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memcpy(subreq->info, ctx->iv, ivsize);
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err = crypto_ablkcipher_encrypt(subreq);
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if (err)
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goto unlock;
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memcpy(ctx->iv, subreq->info, ivsize);
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unlock:
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spin_unlock_bh(&ctx->lock);
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return err;
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}
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static int chainiv_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 chainiv_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 !=
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chainiv_givencrypt_first)
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goto unlock;
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crypto_ablkcipher_crt(geniv)->givencrypt = chainiv_givencrypt;
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err = crypto_rng_get_bytes(crypto_default_rng, ctx->iv,
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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 chainiv_givencrypt(req);
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}
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static int chainiv_init_common(struct crypto_tfm *tfm)
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{
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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 chainiv_init(struct crypto_tfm *tfm)
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{
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struct chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
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spin_lock_init(&ctx->lock);
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return chainiv_init_common(tfm);
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}
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static int async_chainiv_schedule_work(struct async_chainiv_ctx *ctx)
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{
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int queued;
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int err = ctx->err;
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if (!ctx->queue.qlen) {
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smp_mb__before_atomic();
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clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
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if (!ctx->queue.qlen ||
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test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
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goto out;
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}
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queued = queue_work(kcrypto_wq, &ctx->postponed);
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BUG_ON(!queued);
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out:
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return err;
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}
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static int async_chainiv_postpone_request(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 async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
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int err;
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spin_lock_bh(&ctx->lock);
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err = skcipher_enqueue_givcrypt(&ctx->queue, req);
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spin_unlock_bh(&ctx->lock);
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if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
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return err;
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ctx->err = err;
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return async_chainiv_schedule_work(ctx);
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}
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static int async_chainiv_givencrypt_tail(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 async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
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struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
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unsigned int ivsize = crypto_ablkcipher_ivsize(geniv);
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memcpy(req->giv, ctx->iv, ivsize);
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memcpy(subreq->info, ctx->iv, ivsize);
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ctx->err = crypto_ablkcipher_encrypt(subreq);
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if (ctx->err)
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goto out;
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memcpy(ctx->iv, subreq->info, ivsize);
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out:
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return async_chainiv_schedule_work(ctx);
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}
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static int async_chainiv_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 async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
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struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
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ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
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ablkcipher_request_set_callback(subreq, req->creq.base.flags,
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req->creq.base.complete,
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req->creq.base.data);
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ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
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req->creq.nbytes, req->creq.info);
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if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
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goto postpone;
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if (ctx->queue.qlen) {
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clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
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goto postpone;
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}
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return async_chainiv_givencrypt_tail(req);
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postpone:
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return async_chainiv_postpone_request(req);
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}
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static int async_chainiv_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 async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
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int err = 0;
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if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
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goto out;
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if (crypto_ablkcipher_crt(geniv)->givencrypt !=
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async_chainiv_givencrypt_first)
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goto unlock;
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crypto_ablkcipher_crt(geniv)->givencrypt = async_chainiv_givencrypt;
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err = crypto_rng_get_bytes(crypto_default_rng, ctx->iv,
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crypto_ablkcipher_ivsize(geniv));
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unlock:
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clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
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if (err)
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return err;
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out:
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return async_chainiv_givencrypt(req);
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}
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static void async_chainiv_do_postponed(struct work_struct *work)
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{
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struct async_chainiv_ctx *ctx = container_of(work,
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struct async_chainiv_ctx,
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postponed);
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struct skcipher_givcrypt_request *req;
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struct ablkcipher_request *subreq;
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int err;
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/* Only handle one request at a time to avoid hogging keventd. */
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spin_lock_bh(&ctx->lock);
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req = skcipher_dequeue_givcrypt(&ctx->queue);
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spin_unlock_bh(&ctx->lock);
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if (!req) {
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async_chainiv_schedule_work(ctx);
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return;
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}
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subreq = skcipher_givcrypt_reqctx(req);
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subreq->base.flags |= CRYPTO_TFM_REQ_MAY_SLEEP;
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err = async_chainiv_givencrypt_tail(req);
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local_bh_disable();
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skcipher_givcrypt_complete(req, err);
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local_bh_enable();
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}
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static int async_chainiv_init(struct crypto_tfm *tfm)
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{
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struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
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spin_lock_init(&ctx->lock);
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crypto_init_queue(&ctx->queue, 100);
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INIT_WORK(&ctx->postponed, async_chainiv_do_postponed);
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return chainiv_init_common(tfm);
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}
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static void async_chainiv_exit(struct crypto_tfm *tfm)
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{
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struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
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BUG_ON(test_bit(CHAINIV_STATE_INUSE, &ctx->state) || ctx->queue.qlen);
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skcipher_geniv_exit(tfm);
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}
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static struct crypto_template chainiv_tmpl;
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static struct crypto_instance *chainiv_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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inst = skcipher_geniv_alloc(&chainiv_tmpl, tb, 0, 0);
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if (IS_ERR(inst))
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goto put_rng;
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inst->alg.cra_ablkcipher.givencrypt = chainiv_givencrypt_first;
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inst->alg.cra_init = chainiv_init;
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inst->alg.cra_exit = skcipher_geniv_exit;
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inst->alg.cra_ctxsize = sizeof(struct chainiv_ctx);
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if (!crypto_requires_sync(algt->type, algt->mask)) {
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inst->alg.cra_flags |= CRYPTO_ALG_ASYNC;
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inst->alg.cra_ablkcipher.givencrypt =
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async_chainiv_givencrypt_first;
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inst->alg.cra_init = async_chainiv_init;
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inst->alg.cra_exit = async_chainiv_exit;
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inst->alg.cra_ctxsize = sizeof(struct async_chainiv_ctx);
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}
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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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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 chainiv_free(struct crypto_instance *inst)
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{
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skcipher_geniv_free(inst);
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crypto_put_default_rng();
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}
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static struct crypto_template chainiv_tmpl = {
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.name = "chainiv",
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.alloc = chainiv_alloc,
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.free = chainiv_free,
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.module = THIS_MODULE,
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};
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static int __init chainiv_module_init(void)
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{
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return crypto_register_template(&chainiv_tmpl);
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}
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static void chainiv_module_exit(void)
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{
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crypto_unregister_template(&chainiv_tmpl);
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}
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module_init(chainiv_module_init);
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module_exit(chainiv_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Chain IV Generator");
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MODULE_ALIAS_CRYPTO("chainiv");
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