ahash.c

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/*
 * Asynchronous Cryptographic Hash operations.
 *
 * This is the asynchronous version of hash.c with notification of
 * completion via a callback.
 *
 * Copyright (c) 2008 Loc Ho <[email protected]>
 *
 * 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/hash.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/cryptouser.h>
#include <net/netlink.h>

#include "internal.h"

struct ahash_request_priv {
    crypto_completion_t complete;
    void *data;
    u8 *result;
    void *ubuf[] CRYPTO_MINALIGN_ATTR;
};

static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
{
    return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
                halg);
}

static int hash_walk_next(struct crypto_hash_walk *walk)
{
    unsigned int alignmask = walk->alignmask;
    unsigned int offset = walk->offset;
    unsigned int nbytes = min(walk->entrylen,
                  ((unsigned int)(PAGE_SIZE)) - offset);

    walk->data = kmap_atomic(walk->pg);
    walk->data += offset;

    if (offset & alignmask) {
        unsigned int unaligned = alignmask + 1 - (offset & alignmask);
        if (nbytes > unaligned)
            nbytes = unaligned;
    }

    walk->entrylen -= nbytes;
    return nbytes;
}

static int hash_walk_new_entry(struct crypto_hash_walk *walk)
{
    struct scatterlist *sg;

    sg = walk->sg;
    walk->pg = sg_page(sg);
    walk->offset = sg->offset;
    walk->entrylen = sg->length;

    if (walk->entrylen > walk->total)
        walk->entrylen = walk->total;
    walk->total -= walk->entrylen;

    return hash_walk_next(walk);
}

int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
{
    unsigned int alignmask = walk->alignmask;
    unsigned int nbytes = walk->entrylen;

    walk->data -= walk->offset;

    if (nbytes && walk->offset & alignmask && !err) {
        walk->offset = ALIGN(walk->offset, alignmask + 1);
        walk->data += walk->offset;

        nbytes = min(nbytes,
                 ((unsigned int)(PAGE_SIZE)) - walk->offset);
        walk->entrylen -= nbytes;

        return nbytes;
    }

    kunmap_atomic(walk->data);
    crypto_yield(walk->flags);

    if (err)
        return err;

    if (nbytes) {
        walk->offset = 0;
        walk->pg++;
        return hash_walk_next(walk);
    }

    if (!walk->total)
        return 0;

    walk->sg = scatterwalk_sg_next(walk->sg);

    return hash_walk_new_entry(walk);
}
EXPORT_SYMBOL_GPL(crypto_hash_walk_done);

int crypto_hash_walk_first(struct ahash_request *req,
               struct crypto_hash_walk *walk)
{
    walk->total = req->nbytes;

    if (!walk->total)
        return 0;

    walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
    walk->sg = req->src;
    walk->flags = req->base.flags;

    return hash_walk_new_entry(walk);
}
EXPORT_SYMBOL_GPL(crypto_hash_walk_first);

int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
                  struct crypto_hash_walk *walk,
                  struct scatterlist *sg, unsigned int len)
{
    walk->total = len;

    if (!walk->total)
        return 0;

    walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
    walk->sg = sg;
    walk->flags = hdesc->flags;

    return hash_walk_new_entry(walk);
}

static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
                unsigned int keylen)
{
    unsigned long alignmask = crypto_ahash_alignmask(tfm);
    int ret;
    u8 *buffer, *alignbuffer;
    unsigned long absize;

    absize = keylen + alignmask;
    buffer = kmalloc(absize, GFP_KERNEL);
    if (!buffer)
        return -ENOMEM;

    alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
    memcpy(alignbuffer, key, keylen);
    ret = tfm->setkey(tfm, alignbuffer, keylen);
    kzfree(buffer);
    return ret;
}

int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
            unsigned int keylen)
{
    unsigned long alignmask = crypto_ahash_alignmask(tfm);

    if ((unsigned long)key & alignmask)
        return ahash_setkey_unaligned(tfm, key, keylen);

    return tfm->setkey(tfm, key, keylen);
}
EXPORT_SYMBOL_GPL(crypto_ahash_setkey);

static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
              unsigned int keylen)
{
    return -ENOSYS;
}

static inline unsigned int ahash_align_buffer_size(unsigned len,
                           unsigned long mask)
{
    return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
}

static void ahash_op_unaligned_finish(struct ahash_request *req, int err)
{
    struct ahash_request_priv *priv = req->priv;

    if (err == -EINPROGRESS)
        return;

    if (!err)
        memcpy(priv->result, req->result,
               crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));

    kzfree(priv);
}

static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
{
    struct ahash_request *areq = req->data;
    struct ahash_request_priv *priv = areq->priv;
    crypto_completion_t complete = priv->complete;
    void *data = priv->data;

    ahash_op_unaligned_finish(areq, err);

    complete(data, err);
}

static int ahash_op_unaligned(struct ahash_request *req,
                  int (*op)(struct ahash_request *))
{
    struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
    unsigned long alignmask = crypto_ahash_alignmask(tfm);
    unsigned int ds = crypto_ahash_digestsize(tfm);
    struct ahash_request_priv *priv;
    int err;

    priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
               (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
               GFP_KERNEL : GFP_ATOMIC);
    if (!priv)
        return -ENOMEM;

    priv->result = req->result;
    priv->complete = req->base.complete;
    priv->data = req->base.data;

    req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
    req->base.complete = ahash_op_unaligned_done;
    req->base.data = req;
    req->priv = priv;

    err = op(req);
    ahash_op_unaligned_finish(req, err);

    return err;
}

static int crypto_ahash_op(struct ahash_request *req,
               int (*op)(struct ahash_request *))
{
    struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
    unsigned long alignmask = crypto_ahash_alignmask(tfm);

    if ((unsigned long)req->result & alignmask)
        return ahash_op_unaligned(req, op);

    return op(req);
}

int crypto_ahash_final(struct ahash_request *req)
{
    return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
}
EXPORT_SYMBOL_GPL(crypto_ahash_final);

int crypto_ahash_finup(struct ahash_request *req)
{
    return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
}
EXPORT_SYMBOL_GPL(crypto_ahash_finup);

int crypto_ahash_digest(struct ahash_request *req)
{
    return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
}
EXPORT_SYMBOL_GPL(crypto_ahash_digest);

static void ahash_def_finup_finish2(struct ahash_request *req, int err)
{
    struct ahash_request_priv *priv = req->priv;

    if (err == -EINPROGRESS)
        return;

    if (!err)
        memcpy(priv->result, req->result,
               crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));

    kzfree(priv);
}

static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
{
    struct ahash_request *areq = req->data;
    struct ahash_request_priv *priv = areq->priv;
    crypto_completion_t complete = priv->complete;
    void *data = priv->data;

    ahash_def_finup_finish2(areq, err);

    complete(data, err);
}

static int ahash_def_finup_finish1(struct ahash_request *req, int err)
{
    if (err)
        goto out;

    req->base.complete = ahash_def_finup_done2;
    req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
    err = crypto_ahash_reqtfm(req)->final(req);

out:
    ahash_def_finup_finish2(req, err);
    return err;
}

static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
{
    struct ahash_request *areq = req->data;
    struct ahash_request_priv *priv = areq->priv;
    crypto_completion_t complete = priv->complete;
    void *data = priv->data;

    err = ahash_def_finup_finish1(areq, err);

    complete(data, err);
}

static int ahash_def_finup(struct ahash_request *req)
{
    struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
    unsigned long alignmask = crypto_ahash_alignmask(tfm);
    unsigned int ds = crypto_ahash_digestsize(tfm);
    struct ahash_request_priv *priv;

    priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
               (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
               GFP_KERNEL : GFP_ATOMIC);
    if (!priv)
        return -ENOMEM;

    priv->result = req->result;
    priv->complete = req->base.complete;
    priv->data = req->base.data;

    req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
    req->base.complete = ahash_def_finup_done1;
    req->base.data = req;
    req->priv = priv;

    return ahash_def_finup_finish1(req, tfm->update(req));
}

static int ahash_no_export(struct ahash_request *req, void *out)
{
    return -ENOSYS;
}

static int ahash_no_import(struct ahash_request *req, const void *in)
{
    return -ENOSYS;
}

static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
{
    struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
    struct ahash_alg *alg = crypto_ahash_alg(hash);

    hash->setkey = ahash_nosetkey;
    hash->export = ahash_no_export;
    hash->import = ahash_no_import;

    if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
        return crypto_init_shash_ops_async(tfm);

    hash->init = alg->init;
    hash->update = alg->update;
    hash->final = alg->final;
    hash->finup = alg->finup ?: ahash_def_finup;
    hash->digest = alg->digest;

    if (alg->setkey)
        hash->setkey = alg->setkey;
    if (alg->export)
        hash->export = alg->export;
    if (alg->import)
        hash->import = alg->import;

    return 0;
}

static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
{
    if (alg->cra_type == &crypto_ahash_type)
        return alg->cra_ctxsize;

    return sizeof(struct crypto_shash *);
}

#ifdef CONFIG_NET
static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
{
    struct crypto_report_hash rhash;

    snprintf(rhash.type, CRYPTO_MAX_ALG_NAME, "%s", "ahash");

    rhash.blocksize = alg->cra_blocksize;
    rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;

    if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
            sizeof(struct crypto_report_hash), &rhash))
        goto nla_put_failure;
    return 0;

nla_put_failure:
    return -EMSGSIZE;
}
#else
static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
{
    return -ENOSYS;
}
#endif

static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
    __attribute__ ((unused));
static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
{
    seq_printf(m, "type         : ahash\n");
    seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
                         "yes" : "no");
    seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
    seq_printf(m, "digestsize   : %u\n",
           __crypto_hash_alg_common(alg)->digestsize);
}

const struct crypto_type crypto_ahash_type = {
    .extsize = crypto_ahash_extsize,
    .init_tfm = crypto_ahash_init_tfm,
#ifdef CONFIG_PROC_FS
    .show = crypto_ahash_show,
#endif
    .report = crypto_ahash_report,
    .maskclear = ~CRYPTO_ALG_TYPE_MASK,
    .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
    .type = CRYPTO_ALG_TYPE_AHASH,
    .tfmsize = offsetof(struct crypto_ahash, base),
};
EXPORT_SYMBOL_GPL(crypto_ahash_type);

struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
                    u32 mask)
{
    return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_ahash);

static int ahash_prepare_alg(struct ahash_alg *alg)
{
    struct crypto_alg *base = &alg->halg.base;

    if (alg->halg.digestsize > PAGE_SIZE / 8 ||
        alg->halg.statesize > PAGE_SIZE / 8)
        return -EINVAL;

    base->cra_type = &crypto_ahash_type;
    base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
    base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;

    return 0;
}

int crypto_register_ahash(struct ahash_alg *alg)
{
    struct crypto_alg *base = &alg->halg.base;
    int err;

    err = ahash_prepare_alg(alg);
    if (err)
        return err;

    return crypto_register_alg(base);
}
EXPORT_SYMBOL_GPL(crypto_register_ahash);

int crypto_unregister_ahash(struct ahash_alg *alg)
{
    return crypto_unregister_alg(&alg->halg.base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_ahash);

int ahash_register_instance(struct crypto_template *tmpl,
                struct ahash_instance *inst)
{
    int err;

    err = ahash_prepare_alg(&inst->alg);
    if (err)
        return err;

    return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
}
EXPORT_SYMBOL_GPL(ahash_register_instance);

void ahash_free_instance(struct crypto_instance *inst)
{
    crypto_drop_spawn(crypto_instance_ctx(inst));
    kfree(ahash_instance(inst));
}
EXPORT_SYMBOL_GPL(ahash_free_instance);

int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
                struct hash_alg_common *alg,
                struct crypto_instance *inst)
{
    return crypto_init_spawn2(&spawn->base, &alg->base, inst,
                  &crypto_ahash_type);
}
EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);

struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
{
    struct crypto_alg *alg;

    alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
    return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
}
EXPORT_SYMBOL_GPL(ahash_attr_alg);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Asynchronous cryptographic hash type");