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root/crypto/seqiv.c

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DEFINITIONS

This source file includes following definitions.
  1. seqiv_complete2
  2. seqiv_complete
  3. seqiv_aead_complete2
  4. seqiv_aead_complete
  5. seqiv_geniv
  6. seqiv_givencrypt
  7. seqiv_aead_givencrypt
  8. seqiv_givencrypt_first
  9. seqiv_aead_givencrypt_first
  10. seqiv_init
  11. seqiv_aead_init
  12. seqiv_ablkcipher_alloc
  13. seqiv_aead_alloc
  14. seqiv_alloc
  15. seqiv_free
  16. seqiv_module_init
  17. seqiv_module_exit

/*
 * 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 <herbert@gondor.apana.org.au>
 *
 * 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 <crypto/internal/aead.h>
#include <crypto/internal/skcipher.h>
#include <crypto/rng.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/string.h>

struct seqiv_ctx {
        spinlock_t lock;
        u8 salt[] __attribute__ ((aligned(__alignof__(u32))));
};

static void seqiv_complete2(struct skcipher_givcrypt_request *req, int err)
{
        struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
        struct crypto_ablkcipher *geniv;

        if (err == -EINPROGRESS)
                return;

        if (err)
                goto out;

        geniv = skcipher_givcrypt_reqtfm(req);
        memcpy(req->creq.info, subreq->info, crypto_ablkcipher_ivsize(geniv));

out:
        kfree(subreq->info);
}

static void seqiv_complete(struct crypto_async_request *base, int err)
{
        struct skcipher_givcrypt_request *req = base->data;

        seqiv_complete2(req, err);
        skcipher_givcrypt_complete(req, err);
}

static void seqiv_aead_complete2(struct aead_givcrypt_request *req, int err)
{
        struct aead_request *subreq = aead_givcrypt_reqctx(req);
        struct crypto_aead *geniv;

        if (err == -EINPROGRESS)
                return;

        if (err)
                goto out;

        geniv = aead_givcrypt_reqtfm(req);
        memcpy(req->areq.iv, subreq->iv, crypto_aead_ivsize(geniv));

out:
        kfree(subreq->iv);
}

static void seqiv_aead_complete(struct crypto_async_request *base, int err)
{
        struct aead_givcrypt_request *req = base->data;

        seqiv_aead_complete2(req, err);
        aead_givcrypt_complete(req, err);
}

static void seqiv_geniv(struct seqiv_ctx *ctx, u8 *info, u64 seq,
                        unsigned int ivsize)
{
        unsigned int len = ivsize;

        if (ivsize > sizeof(u64)) {
                memset(info, 0, ivsize - sizeof(u64));
                len = sizeof(u64);
        }
        seq = cpu_to_be64(seq);
        memcpy(info + ivsize - len, &seq, len);
        crypto_xor(info, ctx->salt, ivsize);
}

static int seqiv_givencrypt(struct skcipher_givcrypt_request *req)
{
        struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
        struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
        struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
        crypto_completion_t complete;
        void *data;
        u8 *info;
        unsigned int ivsize;
        int err;

        ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));

        complete = req->creq.base.complete;
        data = req->creq.base.data;
        info = req->creq.info;

        ivsize = crypto_ablkcipher_ivsize(geniv);

        if (unlikely(!IS_ALIGNED((unsigned long)info,
                                 crypto_ablkcipher_alignmask(geniv) + 1))) {
                info = kmalloc(ivsize, req->creq.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->creq.base.flags, complete,
                                        data);
        ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
                                     req->creq.nbytes, info);

        seqiv_geniv(ctx, info, req->seq, ivsize);
        memcpy(req->giv, info, ivsize);

        err = crypto_ablkcipher_encrypt(subreq);
        if (unlikely(info != req->creq.info))
                seqiv_complete2(req, err);
        return err;
}

static int seqiv_aead_givencrypt(struct aead_givcrypt_request *req)
{
        struct crypto_aead *geniv = aead_givcrypt_reqtfm(req);
        struct seqiv_ctx *ctx = crypto_aead_ctx(geniv);
        struct aead_request *areq = &req->areq;
        struct aead_request *subreq = aead_givcrypt_reqctx(req);
        crypto_completion_t complete;
        void *data;
        u8 *info;
        unsigned int ivsize;
        int err;

        aead_request_set_tfm(subreq, aead_geniv_base(geniv));

        complete = areq->base.complete;
        data = areq->base.data;
        info = areq->iv;

        ivsize = crypto_aead_ivsize(geniv);

        if (unlikely(!IS_ALIGNED((unsigned long)info,
                                 crypto_aead_alignmask(geniv) + 1))) {
                info = kmalloc(ivsize, areq->base.flags &
                                       CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
                                                                  GFP_ATOMIC);
                if (!info)
                        return -ENOMEM;

                complete = seqiv_aead_complete;
                data = req;
        }

        aead_request_set_callback(subreq, areq->base.flags, complete, data);
        aead_request_set_crypt(subreq, areq->src, areq->dst, areq->cryptlen,
                               info);
        aead_request_set_assoc(subreq, areq->assoc, areq->assoclen);

        seqiv_geniv(ctx, info, req->seq, ivsize);
        memcpy(req->giv, info, ivsize);

        err = crypto_aead_encrypt(subreq);
        if (unlikely(info != areq->iv))
                seqiv_aead_complete2(req, err);
        return err;
}

static int seqiv_givencrypt_first(struct skcipher_givcrypt_request *req)
{
        struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
        struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
        int err = 0;

        spin_lock_bh(&ctx->lock);
        if (crypto_ablkcipher_crt(geniv)->givencrypt != seqiv_givencrypt_first)
                goto unlock;

        crypto_ablkcipher_crt(geniv)->givencrypt = seqiv_givencrypt;
        err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
                                   crypto_ablkcipher_ivsize(geniv));

unlock:
        spin_unlock_bh(&ctx->lock);

        if (err)
                return err;

        return seqiv_givencrypt(req);
}

static int seqiv_aead_givencrypt_first(struct aead_givcrypt_request *req)
{
        struct crypto_aead *geniv = aead_givcrypt_reqtfm(req);
        struct seqiv_ctx *ctx = crypto_aead_ctx(geniv);
        int err = 0;

        spin_lock_bh(&ctx->lock);
        if (crypto_aead_crt(geniv)->givencrypt != seqiv_aead_givencrypt_first)
                goto unlock;

        crypto_aead_crt(geniv)->givencrypt = seqiv_aead_givencrypt;
        err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
                                   crypto_aead_ivsize(geniv));

unlock:
        spin_unlock_bh(&ctx->lock);

        if (err)
                return err;

        return seqiv_aead_givencrypt(req);
}

static int seqiv_init(struct crypto_tfm *tfm)
{
        struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm);
        struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);

        spin_lock_init(&ctx->lock);

        tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request);

        return skcipher_geniv_init(tfm);
}

static int seqiv_aead_init(struct crypto_tfm *tfm)
{
        struct crypto_aead *geniv = __crypto_aead_cast(tfm);
        struct seqiv_ctx *ctx = crypto_aead_ctx(geniv);

        spin_lock_init(&ctx->lock);

        tfm->crt_aead.reqsize = sizeof(struct aead_request);

        return aead_geniv_init(tfm);
}

static struct crypto_template seqiv_tmpl;

static struct crypto_instance *seqiv_ablkcipher_alloc(struct rtattr **tb)
{
        struct crypto_instance *inst;

        inst = skcipher_geniv_alloc(&seqiv_tmpl, tb, 0, 0);

        if (IS_ERR(inst))
                goto out;

        inst->alg.cra_ablkcipher.givencrypt = seqiv_givencrypt_first;

        inst->alg.cra_init = seqiv_init;
        inst->alg.cra_exit = skcipher_geniv_exit;

        inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize;

out:
        return inst;
}

static struct crypto_instance *seqiv_aead_alloc(struct rtattr **tb)
{
        struct crypto_instance *inst;

        inst = aead_geniv_alloc(&seqiv_tmpl, tb, 0, 0);

        if (IS_ERR(inst))
                goto out;

        inst->alg.cra_aead.givencrypt = seqiv_aead_givencrypt_first;

        inst->alg.cra_init = seqiv_aead_init;
        inst->alg.cra_exit = aead_geniv_exit;

        inst->alg.cra_ctxsize = inst->alg.cra_aead.ivsize;

out:
        return inst;
}

static struct crypto_instance *seqiv_alloc(struct rtattr **tb)
{
        struct crypto_attr_type *algt;
        struct crypto_instance *inst;
        int err;

        algt = crypto_get_attr_type(tb);
        err = PTR_ERR(algt);
        if (IS_ERR(algt))
                return ERR_PTR(err);

        err = crypto_get_default_rng();
        if (err)
                return ERR_PTR(err);

        if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
                inst = seqiv_ablkcipher_alloc(tb);
        else
                inst = seqiv_aead_alloc(tb);

        if (IS_ERR(inst))
                goto put_rng;

        inst->alg.cra_alignmask |= __alignof__(u32) - 1;
        inst->alg.cra_ctxsize += sizeof(struct seqiv_ctx);

out:
        return inst;

put_rng:
        crypto_put_default_rng();
        goto out;
}

static void seqiv_free(struct crypto_instance *inst)
{
        if ((inst->alg.cra_flags ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
                skcipher_geniv_free(inst);
        else
                aead_geniv_free(inst);
        crypto_put_default_rng();
}

static struct crypto_template seqiv_tmpl = {
        .name = "seqiv",
        .alloc = seqiv_alloc,
        .free = seqiv_free,
        .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");

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