root/crypto/ahash.c

DEFINITIONS

1. hash_walk_next
2. hash_walk_new_entry
3. crypto_hash_walk_done
4. crypto_hash_walk_first
5. ahash_setkey_unaligned
6. ahash_setkey
7. crypto_ahash_ctxsize
8. crypto_init_ahash_ops
9. crypto_ahash_show

/*
 * Asynchronous Cryptographic Hash operations.
 *
 * This is the asynchronous version of hash.c with notification of
 * completion via a callback.
 *
 * Copyright (c) 2008 Loc Ho <lho@amcc.com>
 *
 * 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 "internal.h"

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 = crypto_kmap(walk->pg, 0);
        walk->data += offset;

        if (offset & alignmask)
                nbytes = alignmask + 1 - (offset & alignmask);

        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 += alignmask - 1;
                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;
        }

        crypto_kunmap(walk->data, 0);
        crypto_yield(walk->flags);

        if (err)
                return err;

        walk->offset = 0;

        if (nbytes)
                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);

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

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

        alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
        memcpy(alignbuffer, key, keylen);
        ret = ahash->setkey(tfm, alignbuffer, keylen);
        memset(alignbuffer, 0, keylen);
        kfree(buffer);
        return ret;
}

static int ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
                        unsigned int keylen)
{
        struct ahash_alg *ahash = crypto_ahash_alg(tfm);
        unsigned long alignmask = crypto_ahash_alignmask(tfm);

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

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

static unsigned int crypto_ahash_ctxsize(struct crypto_alg *alg, u32 type,
                                        u32 mask)
{
        return alg->cra_ctxsize;
}

static int crypto_init_ahash_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
{
        struct ahash_alg *alg = &tfm->__crt_alg->cra_ahash;
        struct ahash_tfm *crt   = &tfm->crt_ahash;

        if (alg->digestsize > PAGE_SIZE / 8)
                return -EINVAL;

        crt->init = alg->init;
        crt->update = alg->update;
        crt->final  = alg->final;
        crt->digest = alg->digest;
        crt->setkey = ahash_setkey;
        crt->digestsize = alg->digestsize;

        return 0;
}

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", alg->cra_hash.digestsize);
}

const struct crypto_type crypto_ahash_type = {
        .ctxsize = crypto_ahash_ctxsize,
        .init = crypto_init_ahash_ops,
#ifdef CONFIG_PROC_FS
        .show = crypto_ahash_show,
#endif
};
EXPORT_SYMBOL_GPL(crypto_ahash_type);

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