pcrypt.c

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/*
 * pcrypt - Parallel crypto wrapper.
 *
 * Copyright (C) 2009 secunet Security Networks AG
 * Copyright (C) 2009 Steffen Klassert <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <crypto/algapi.h>
#include <crypto/internal/aead.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/notifier.h>
#include <linux/kobject.h>
#include <linux/cpu.h>
#include <crypto/pcrypt.h>

struct padata_pcrypt {
    struct padata_instance *pinst;
    struct workqueue_struct *wq;

    /*
     * Cpumask for callback CPUs. It should be
     * equal to serial cpumask of corresponding padata instance,
     * so it is updated when padata notifies us about serial
     * cpumask change.
     *
     * cb_cpumask is protected by RCU. This fact prevents us from
     * using cpumask_var_t directly because the actual type of
     * cpumsak_var_t depends on kernel configuration(particularly on
     * CONFIG_CPUMASK_OFFSTACK macro). Depending on the configuration
     * cpumask_var_t may be either a pointer to the struct cpumask
     * or a variable allocated on the stack. Thus we can not safely use
     * cpumask_var_t with RCU operations such as rcu_assign_pointer or
     * rcu_dereference. So cpumask_var_t is wrapped with struct
     * pcrypt_cpumask which makes possible to use it with RCU.
     */
    struct pcrypt_cpumask {
        cpumask_var_t mask;
    } *cb_cpumask;
    struct notifier_block nblock;
};

static struct padata_pcrypt pencrypt;
static struct padata_pcrypt pdecrypt;
static struct kset           *pcrypt_kset;

struct pcrypt_instance_ctx {
    struct crypto_spawn spawn;
    unsigned int tfm_count;
};

struct pcrypt_aead_ctx {
    struct crypto_aead *child;
    unsigned int cb_cpu;
};

static int pcrypt_do_parallel(struct padata_priv *padata, unsigned int *cb_cpu,
                  struct padata_pcrypt *pcrypt)
{
    unsigned int cpu_index, cpu, i;
    struct pcrypt_cpumask *cpumask;

    cpu = *cb_cpu;

    rcu_read_lock_bh();
    cpumask = rcu_dereference(pcrypt->cb_cpumask);
    if (cpumask_test_cpu(cpu, cpumask->mask))
            goto out;

    if (!cpumask_weight(cpumask->mask))
            goto out;

    cpu_index = cpu % cpumask_weight(cpumask->mask);

    cpu = cpumask_first(cpumask->mask);
    for (i = 0; i < cpu_index; i++)
        cpu = cpumask_next(cpu, cpumask->mask);

    *cb_cpu = cpu;

out:
    rcu_read_unlock_bh();
    return padata_do_parallel(pcrypt->pinst, padata, cpu);
}

static int pcrypt_aead_setkey(struct crypto_aead *parent,
                  const u8 *key, unsigned int keylen)
{
    struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(parent);

    return crypto_aead_setkey(ctx->child, key, keylen);
}

static int pcrypt_aead_setauthsize(struct crypto_aead *parent,
                   unsigned int authsize)
{
    struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(parent);

    return crypto_aead_setauthsize(ctx->child, authsize);
}

static void pcrypt_aead_serial(struct padata_priv *padata)
{
    struct pcrypt_request *preq = pcrypt_padata_request(padata);
    struct aead_request *req = pcrypt_request_ctx(preq);

    aead_request_complete(req->base.data, padata->info);
}

static void pcrypt_aead_giv_serial(struct padata_priv *padata)
{
    struct pcrypt_request *preq = pcrypt_padata_request(padata);
    struct aead_givcrypt_request *req = pcrypt_request_ctx(preq);

    aead_request_complete(req->areq.base.data, padata->info);
}

static void pcrypt_aead_done(struct crypto_async_request *areq, int err)
{
    struct aead_request *req = areq->data;
    struct pcrypt_request *preq = aead_request_ctx(req);
    struct padata_priv *padata = pcrypt_request_padata(preq);

    padata->info = err;
    req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;

    padata_do_serial(padata);
}

static void pcrypt_aead_enc(struct padata_priv *padata)
{
    struct pcrypt_request *preq = pcrypt_padata_request(padata);
    struct aead_request *req = pcrypt_request_ctx(preq);

    padata->info = crypto_aead_encrypt(req);

    if (padata->info == -EINPROGRESS)
        return;

    padata_do_serial(padata);
}

static int pcrypt_aead_encrypt(struct aead_request *req)
{
    int err;
    struct pcrypt_request *preq = aead_request_ctx(req);
    struct aead_request *creq = pcrypt_request_ctx(preq);
    struct padata_priv *padata = pcrypt_request_padata(preq);
    struct crypto_aead *aead = crypto_aead_reqtfm(req);
    struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(aead);
    u32 flags = aead_request_flags(req);

    memset(padata, 0, sizeof(struct padata_priv));

    padata->parallel = pcrypt_aead_enc;
    padata->serial = pcrypt_aead_serial;

    aead_request_set_tfm(creq, ctx->child);
    aead_request_set_callback(creq, flags & ~CRYPTO_TFM_REQ_MAY_SLEEP,
                  pcrypt_aead_done, req);
    aead_request_set_crypt(creq, req->src, req->dst,
                   req->cryptlen, req->iv);
    aead_request_set_assoc(creq, req->assoc, req->assoclen);

    err = pcrypt_do_parallel(padata, &ctx->cb_cpu, &pencrypt);
    if (!err)
        return -EINPROGRESS;

    return err;
}

static void pcrypt_aead_dec(struct padata_priv *padata)
{
    struct pcrypt_request *preq = pcrypt_padata_request(padata);
    struct aead_request *req = pcrypt_request_ctx(preq);

    padata->info = crypto_aead_decrypt(req);

    if (padata->info == -EINPROGRESS)
        return;

    padata_do_serial(padata);
}

static int pcrypt_aead_decrypt(struct aead_request *req)
{
    int err;
    struct pcrypt_request *preq = aead_request_ctx(req);
    struct aead_request *creq = pcrypt_request_ctx(preq);
    struct padata_priv *padata = pcrypt_request_padata(preq);
    struct crypto_aead *aead = crypto_aead_reqtfm(req);
    struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(aead);
    u32 flags = aead_request_flags(req);

    memset(padata, 0, sizeof(struct padata_priv));

    padata->parallel = pcrypt_aead_dec;
    padata->serial = pcrypt_aead_serial;

    aead_request_set_tfm(creq, ctx->child);
    aead_request_set_callback(creq, flags & ~CRYPTO_TFM_REQ_MAY_SLEEP,
                  pcrypt_aead_done, req);
    aead_request_set_crypt(creq, req->src, req->dst,
                   req->cryptlen, req->iv);
    aead_request_set_assoc(creq, req->assoc, req->assoclen);

    err = pcrypt_do_parallel(padata, &ctx->cb_cpu, &pdecrypt);
    if (!err)
        return -EINPROGRESS;

    return err;
}

static void pcrypt_aead_givenc(struct padata_priv *padata)
{
    struct pcrypt_request *preq = pcrypt_padata_request(padata);
    struct aead_givcrypt_request *req = pcrypt_request_ctx(preq);

    padata->info = crypto_aead_givencrypt(req);

    if (padata->info == -EINPROGRESS)
        return;

    padata_do_serial(padata);
}

static int pcrypt_aead_givencrypt(struct aead_givcrypt_request *req)
{
    int err;
    struct aead_request *areq = &req->areq;
    struct pcrypt_request *preq = aead_request_ctx(areq);
    struct aead_givcrypt_request *creq = pcrypt_request_ctx(preq);
    struct padata_priv *padata = pcrypt_request_padata(preq);
    struct crypto_aead *aead = aead_givcrypt_reqtfm(req);
    struct pcrypt_aead_ctx *ctx = crypto_aead_ctx(aead);
    u32 flags = aead_request_flags(areq);

    memset(padata, 0, sizeof(struct padata_priv));

    padata->parallel = pcrypt_aead_givenc;
    padata->serial = pcrypt_aead_giv_serial;

    aead_givcrypt_set_tfm(creq, ctx->child);
    aead_givcrypt_set_callback(creq, flags & ~CRYPTO_TFM_REQ_MAY_SLEEP,
                   pcrypt_aead_done, areq);
    aead_givcrypt_set_crypt(creq, areq->src, areq->dst,
                areq->cryptlen, areq->iv);
    aead_givcrypt_set_assoc(creq, areq->assoc, areq->assoclen);
    aead_givcrypt_set_giv(creq, req->giv, req->seq);

    err = pcrypt_do_parallel(padata, &ctx->cb_cpu, &pencrypt);
    if (!err)
        return -EINPROGRESS;

    return err;
}

static int pcrypt_aead_init_tfm(struct crypto_tfm *tfm)
{
    int cpu, cpu_index;
    struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
    struct pcrypt_instance_ctx *ictx = crypto_instance_ctx(inst);
    struct pcrypt_aead_ctx *ctx = crypto_tfm_ctx(tfm);
    struct crypto_aead *cipher;

    ictx->tfm_count++;

    cpu_index = ictx->tfm_count % cpumask_weight(cpu_online_mask);

    ctx->cb_cpu = cpumask_first(cpu_online_mask);
    for (cpu = 0; cpu < cpu_index; cpu++)
        ctx->cb_cpu = cpumask_next(ctx->cb_cpu, cpu_online_mask);

    cipher = crypto_spawn_aead(crypto_instance_ctx(inst));

    if (IS_ERR(cipher))
        return PTR_ERR(cipher);

    ctx->child = cipher;
    tfm->crt_aead.reqsize = sizeof(struct pcrypt_request)
        + sizeof(struct aead_givcrypt_request)
        + crypto_aead_reqsize(cipher);

    return 0;
}

static void pcrypt_aead_exit_tfm(struct crypto_tfm *tfm)
{
    struct pcrypt_aead_ctx *ctx = crypto_tfm_ctx(tfm);

    crypto_free_aead(ctx->child);
}

static struct crypto_instance *pcrypt_alloc_instance(struct crypto_alg *alg)
{
    struct crypto_instance *inst;
    struct pcrypt_instance_ctx *ctx;
    int err;

    inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
    if (!inst) {
        inst = ERR_PTR(-ENOMEM);
        goto out;
    }

    err = -ENAMETOOLONG;
    if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
             "pcrypt(%s)", alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
        goto out_free_inst;

    memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);

    ctx = crypto_instance_ctx(inst);
    err = crypto_init_spawn(&ctx->spawn, alg, inst,
                CRYPTO_ALG_TYPE_MASK);
    if (err)
        goto out_free_inst;

    inst->alg.cra_priority = alg->cra_priority + 100;
    inst->alg.cra_blocksize = alg->cra_blocksize;
    inst->alg.cra_alignmask = alg->cra_alignmask;

out:
    return inst;

out_free_inst:
    kfree(inst);
    inst = ERR_PTR(err);
    goto out;
}

static struct crypto_instance *pcrypt_alloc_aead(struct rtattr **tb,
                         u32 type, u32 mask)
{
    struct crypto_instance *inst;
    struct crypto_alg *alg;

    alg = crypto_get_attr_alg(tb, type, (mask & CRYPTO_ALG_TYPE_MASK));
    if (IS_ERR(alg))
        return ERR_CAST(alg);

    inst = pcrypt_alloc_instance(alg);
    if (IS_ERR(inst))
        goto out_put_alg;

    inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_ASYNC;
    inst->alg.cra_type = &crypto_aead_type;

    inst->alg.cra_aead.ivsize = alg->cra_aead.ivsize;
    inst->alg.cra_aead.geniv = alg->cra_aead.geniv;
    inst->alg.cra_aead.maxauthsize = alg->cra_aead.maxauthsize;

    inst->alg.cra_ctxsize = sizeof(struct pcrypt_aead_ctx);

    inst->alg.cra_init = pcrypt_aead_init_tfm;
    inst->alg.cra_exit = pcrypt_aead_exit_tfm;

    inst->alg.cra_aead.setkey = pcrypt_aead_setkey;
    inst->alg.cra_aead.setauthsize = pcrypt_aead_setauthsize;
    inst->alg.cra_aead.encrypt = pcrypt_aead_encrypt;
    inst->alg.cra_aead.decrypt = pcrypt_aead_decrypt;
    inst->alg.cra_aead.givencrypt = pcrypt_aead_givencrypt;

out_put_alg:
    crypto_mod_put(alg);
    return inst;
}

static struct crypto_instance *pcrypt_alloc(struct rtattr **tb)
{
    struct crypto_attr_type *algt;

    algt = crypto_get_attr_type(tb);
    if (IS_ERR(algt))
        return ERR_CAST(algt);

    switch (algt->type & algt->mask & CRYPTO_ALG_TYPE_MASK) {
    case CRYPTO_ALG_TYPE_AEAD:
        return pcrypt_alloc_aead(tb, algt->type, algt->mask);
    }

    return ERR_PTR(-EINVAL);
}

static void pcrypt_free(struct crypto_instance *inst)
{
    struct pcrypt_instance_ctx *ctx = crypto_instance_ctx(inst);

    crypto_drop_spawn(&ctx->spawn);
    kfree(inst);
}

static int pcrypt_cpumask_change_notify(struct notifier_block *self,
                    unsigned long val, void *data)
{
    struct padata_pcrypt *pcrypt;
    struct pcrypt_cpumask *new_mask, *old_mask;
    struct padata_cpumask *cpumask = (struct padata_cpumask *)data;

    if (!(val & PADATA_CPU_SERIAL))
        return 0;

    pcrypt = container_of(self, struct padata_pcrypt, nblock);
    new_mask = kmalloc(sizeof(*new_mask), GFP_KERNEL);
    if (!new_mask)
        return -ENOMEM;
    if (!alloc_cpumask_var(&new_mask->mask, GFP_KERNEL)) {
        kfree(new_mask);
        return -ENOMEM;
    }

    old_mask = pcrypt->cb_cpumask;

    cpumask_copy(new_mask->mask, cpumask->cbcpu);
    rcu_assign_pointer(pcrypt->cb_cpumask, new_mask);
    synchronize_rcu_bh();

    free_cpumask_var(old_mask->mask);
    kfree(old_mask);
    return 0;
}

static int pcrypt_sysfs_add(struct padata_instance *pinst, const char *name)
{
    int ret;

    pinst->kobj.kset = pcrypt_kset;
    ret = kobject_add(&pinst->kobj, NULL, name);
    if (!ret)
        kobject_uevent(&pinst->kobj, KOBJ_ADD);

    return ret;
}

static int pcrypt_init_padata(struct padata_pcrypt *pcrypt,
                  const char *name)
{
    int ret = -ENOMEM;
    struct pcrypt_cpumask *mask;

    get_online_cpus();

    pcrypt->wq = alloc_workqueue(name,
                     WQ_MEM_RECLAIM | WQ_CPU_INTENSIVE, 1);
    if (!pcrypt->wq)
        goto err;

    pcrypt->pinst = padata_alloc_possible(pcrypt->wq);
    if (!pcrypt->pinst)
        goto err_destroy_workqueue;

    mask = kmalloc(sizeof(*mask), GFP_KERNEL);
    if (!mask)
        goto err_free_padata;
    if (!alloc_cpumask_var(&mask->mask, GFP_KERNEL)) {
        kfree(mask);
        goto err_free_padata;
    }

    cpumask_and(mask->mask, cpu_possible_mask, cpu_online_mask);
    rcu_assign_pointer(pcrypt->cb_cpumask, mask);

    pcrypt->nblock.notifier_call = pcrypt_cpumask_change_notify;
    ret = padata_register_cpumask_notifier(pcrypt->pinst, &pcrypt->nblock);
    if (ret)
        goto err_free_cpumask;

    ret = pcrypt_sysfs_add(pcrypt->pinst, name);
    if (ret)
        goto err_unregister_notifier;

    put_online_cpus();

    return ret;

err_unregister_notifier:
    padata_unregister_cpumask_notifier(pcrypt->pinst, &pcrypt->nblock);
err_free_cpumask:
    free_cpumask_var(mask->mask);
    kfree(mask);
err_free_padata:
    padata_free(pcrypt->pinst);
err_destroy_workqueue:
    destroy_workqueue(pcrypt->wq);
err:
    put_online_cpus();

    return ret;
}

static void pcrypt_fini_padata(struct padata_pcrypt *pcrypt)
{
    free_cpumask_var(pcrypt->cb_cpumask->mask);
    kfree(pcrypt->cb_cpumask);

    padata_stop(pcrypt->pinst);
    padata_unregister_cpumask_notifier(pcrypt->pinst, &pcrypt->nblock);
    destroy_workqueue(pcrypt->wq);
    padata_free(pcrypt->pinst);
}

static struct crypto_template pcrypt_tmpl = {
    .name = "pcrypt",
    .alloc = pcrypt_alloc,
    .free = pcrypt_free,
    .module = THIS_MODULE,
};

static int __init pcrypt_init(void)
{
    int err = -ENOMEM;

    pcrypt_kset = kset_create_and_add("pcrypt", NULL, kernel_kobj);
    if (!pcrypt_kset)
        goto err;

    err = pcrypt_init_padata(&pencrypt, "pencrypt");
    if (err)
        goto err_unreg_kset;

    err = pcrypt_init_padata(&pdecrypt, "pdecrypt");
    if (err)
        goto err_deinit_pencrypt;

    padata_start(pencrypt.pinst);
    padata_start(pdecrypt.pinst);

    return crypto_register_template(&pcrypt_tmpl);

err_deinit_pencrypt:
    pcrypt_fini_padata(&pencrypt);
err_unreg_kset:
    kset_unregister(pcrypt_kset);
err:
    return err;
}

static void __exit pcrypt_exit(void)
{
    pcrypt_fini_padata(&pencrypt);
    pcrypt_fini_padata(&pdecrypt);

    kset_unregister(pcrypt_kset);
    crypto_unregister_template(&pcrypt_tmpl);
}

module_init(pcrypt_init);
module_exit(pcrypt_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Steffen Klassert <[email protected]>");
MODULE_DESCRIPTION("Parallel crypto wrapper");