shash.c

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/*
 * Synchronous Cryptographic Hash operations.
 *
 * Copyright (c) 2008 Herbert Xu <[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/scatterwalk.h>
#include <crypto/internal/hash.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/cryptouser.h>
#include <net/netlink.h>

#include "internal.h"

static const struct crypto_type crypto_shash_type;

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

static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key,
                  unsigned int keylen)
{
    struct shash_alg *shash = crypto_shash_alg(tfm);
    unsigned long alignmask = crypto_shash_alignmask(tfm);
    unsigned long absize;
    u8 *buffer, *alignbuffer;
    int err;

    absize = keylen + (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
    buffer = kmalloc(absize, GFP_KERNEL);
    if (!buffer)
        return -ENOMEM;

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

int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key,
            unsigned int keylen)
{
    struct shash_alg *shash = crypto_shash_alg(tfm);
    unsigned long alignmask = crypto_shash_alignmask(tfm);

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

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

static inline unsigned int shash_align_buffer_size(unsigned len,
                           unsigned long mask)
{
    return len + (mask & ~(__alignof__(u8 __attribute__ ((aligned))) - 1));
}

static int shash_update_unaligned(struct shash_desc *desc, const u8 *data,
                  unsigned int len)
{
    struct crypto_shash *tfm = desc->tfm;
    struct shash_alg *shash = crypto_shash_alg(tfm);
    unsigned long alignmask = crypto_shash_alignmask(tfm);
    unsigned int unaligned_len = alignmask + 1 -
                     ((unsigned long)data & alignmask);
    u8 ubuf[shash_align_buffer_size(unaligned_len, alignmask)]
        __attribute__ ((aligned));
    u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1);
    int err;

    if (unaligned_len > len)
        unaligned_len = len;

    memcpy(buf, data, unaligned_len);
    err = shash->update(desc, buf, unaligned_len);
    memset(buf, 0, unaligned_len);

    return err ?:
           shash->update(desc, data + unaligned_len, len - unaligned_len);
}

int crypto_shash_update(struct shash_desc *desc, const u8 *data,
            unsigned int len)
{
    struct crypto_shash *tfm = desc->tfm;
    struct shash_alg *shash = crypto_shash_alg(tfm);
    unsigned long alignmask = crypto_shash_alignmask(tfm);

    if ((unsigned long)data & alignmask)
        return shash_update_unaligned(desc, data, len);

    return shash->update(desc, data, len);
}
EXPORT_SYMBOL_GPL(crypto_shash_update);

static int shash_final_unaligned(struct shash_desc *desc, u8 *out)
{
    struct crypto_shash *tfm = desc->tfm;
    unsigned long alignmask = crypto_shash_alignmask(tfm);
    struct shash_alg *shash = crypto_shash_alg(tfm);
    unsigned int ds = crypto_shash_digestsize(tfm);
    u8 ubuf[shash_align_buffer_size(ds, alignmask)]
        __attribute__ ((aligned));
    u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1);
    int err;

    err = shash->final(desc, buf);
    if (err)
        goto out;

    memcpy(out, buf, ds);

out:
    memset(buf, 0, ds);
    return err;
}

int crypto_shash_final(struct shash_desc *desc, u8 *out)
{
    struct crypto_shash *tfm = desc->tfm;
    struct shash_alg *shash = crypto_shash_alg(tfm);
    unsigned long alignmask = crypto_shash_alignmask(tfm);

    if ((unsigned long)out & alignmask)
        return shash_final_unaligned(desc, out);

    return shash->final(desc, out);
}
EXPORT_SYMBOL_GPL(crypto_shash_final);

static int shash_finup_unaligned(struct shash_desc *desc, const u8 *data,
                 unsigned int len, u8 *out)
{
    return crypto_shash_update(desc, data, len) ?:
           crypto_shash_final(desc, out);
}

int crypto_shash_finup(struct shash_desc *desc, const u8 *data,
               unsigned int len, u8 *out)
{
    struct crypto_shash *tfm = desc->tfm;
    struct shash_alg *shash = crypto_shash_alg(tfm);
    unsigned long alignmask = crypto_shash_alignmask(tfm);

    if (((unsigned long)data | (unsigned long)out) & alignmask)
        return shash_finup_unaligned(desc, data, len, out);

    return shash->finup(desc, data, len, out);
}
EXPORT_SYMBOL_GPL(crypto_shash_finup);

static int shash_digest_unaligned(struct shash_desc *desc, const u8 *data,
                  unsigned int len, u8 *out)
{
    return crypto_shash_init(desc) ?:
           crypto_shash_finup(desc, data, len, out);
}

int crypto_shash_digest(struct shash_desc *desc, const u8 *data,
            unsigned int len, u8 *out)
{
    struct crypto_shash *tfm = desc->tfm;
    struct shash_alg *shash = crypto_shash_alg(tfm);
    unsigned long alignmask = crypto_shash_alignmask(tfm);

    if (((unsigned long)data | (unsigned long)out) & alignmask)
        return shash_digest_unaligned(desc, data, len, out);

    return shash->digest(desc, data, len, out);
}
EXPORT_SYMBOL_GPL(crypto_shash_digest);

static int shash_default_export(struct shash_desc *desc, void *out)
{
    memcpy(out, shash_desc_ctx(desc), crypto_shash_descsize(desc->tfm));
    return 0;
}

static int shash_default_import(struct shash_desc *desc, const void *in)
{
    memcpy(shash_desc_ctx(desc), in, crypto_shash_descsize(desc->tfm));
    return 0;
}

static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
                  unsigned int keylen)
{
    struct crypto_shash **ctx = crypto_ahash_ctx(tfm);

    return crypto_shash_setkey(*ctx, key, keylen);
}

static int shash_async_init(struct ahash_request *req)
{
    struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
    struct shash_desc *desc = ahash_request_ctx(req);

    desc->tfm = *ctx;
    desc->flags = req->base.flags;

    return crypto_shash_init(desc);
}

int shash_ahash_update(struct ahash_request *req, struct shash_desc *desc)
{
    struct crypto_hash_walk walk;
    int nbytes;

    for (nbytes = crypto_hash_walk_first(req, &walk); nbytes > 0;
         nbytes = crypto_hash_walk_done(&walk, nbytes))
        nbytes = crypto_shash_update(desc, walk.data, nbytes);

    return nbytes;
}
EXPORT_SYMBOL_GPL(shash_ahash_update);

static int shash_async_update(struct ahash_request *req)
{
    return shash_ahash_update(req, ahash_request_ctx(req));
}

static int shash_async_final(struct ahash_request *req)
{
    return crypto_shash_final(ahash_request_ctx(req), req->result);
}

int shash_ahash_finup(struct ahash_request *req, struct shash_desc *desc)
{
    struct crypto_hash_walk walk;
    int nbytes;

    nbytes = crypto_hash_walk_first(req, &walk);
    if (!nbytes)
        return crypto_shash_final(desc, req->result);

    do {
        nbytes = crypto_hash_walk_last(&walk) ?
             crypto_shash_finup(desc, walk.data, nbytes,
                        req->result) :
             crypto_shash_update(desc, walk.data, nbytes);
        nbytes = crypto_hash_walk_done(&walk, nbytes);
    } while (nbytes > 0);

    return nbytes;
}
EXPORT_SYMBOL_GPL(shash_ahash_finup);

static int shash_async_finup(struct ahash_request *req)
{
    struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
    struct shash_desc *desc = ahash_request_ctx(req);

    desc->tfm = *ctx;
    desc->flags = req->base.flags;

    return shash_ahash_finup(req, desc);
}

int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc)
{
    struct scatterlist *sg = req->src;
    unsigned int offset = sg->offset;
    unsigned int nbytes = req->nbytes;
    int err;

    if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
        void *data;

        data = kmap_atomic(sg_page(sg));
        err = crypto_shash_digest(desc, data + offset, nbytes,
                      req->result);
        kunmap_atomic(data);
        crypto_yield(desc->flags);
    } else
        err = crypto_shash_init(desc) ?:
              shash_ahash_finup(req, desc);

    return err;
}
EXPORT_SYMBOL_GPL(shash_ahash_digest);

static int shash_async_digest(struct ahash_request *req)
{
    struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
    struct shash_desc *desc = ahash_request_ctx(req);

    desc->tfm = *ctx;
    desc->flags = req->base.flags;

    return shash_ahash_digest(req, desc);
}

static int shash_async_export(struct ahash_request *req, void *out)
{
    return crypto_shash_export(ahash_request_ctx(req), out);
}

static int shash_async_import(struct ahash_request *req, const void *in)
{
    struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
    struct shash_desc *desc = ahash_request_ctx(req);

    desc->tfm = *ctx;
    desc->flags = req->base.flags;

    return crypto_shash_import(desc, in);
}

static void crypto_exit_shash_ops_async(struct crypto_tfm *tfm)
{
    struct crypto_shash **ctx = crypto_tfm_ctx(tfm);

    crypto_free_shash(*ctx);
}

int crypto_init_shash_ops_async(struct crypto_tfm *tfm)
{
    struct crypto_alg *calg = tfm->__crt_alg;
    struct shash_alg *alg = __crypto_shash_alg(calg);
    struct crypto_ahash *crt = __crypto_ahash_cast(tfm);
    struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
    struct crypto_shash *shash;

    if (!crypto_mod_get(calg))
        return -EAGAIN;

    shash = crypto_create_tfm(calg, &crypto_shash_type);
    if (IS_ERR(shash)) {
        crypto_mod_put(calg);
        return PTR_ERR(shash);
    }

    *ctx = shash;
    tfm->exit = crypto_exit_shash_ops_async;

    crt->init = shash_async_init;
    crt->update = shash_async_update;
    crt->final = shash_async_final;
    crt->finup = shash_async_finup;
    crt->digest = shash_async_digest;

    if (alg->setkey)
        crt->setkey = shash_async_setkey;
    if (alg->export)
        crt->export = shash_async_export;
    if (alg->import)
        crt->import = shash_async_import;

    crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);

    return 0;
}

static int shash_compat_setkey(struct crypto_hash *tfm, const u8 *key,
                   unsigned int keylen)
{
    struct shash_desc **descp = crypto_hash_ctx(tfm);
    struct shash_desc *desc = *descp;

    return crypto_shash_setkey(desc->tfm, key, keylen);
}

static int shash_compat_init(struct hash_desc *hdesc)
{
    struct shash_desc **descp = crypto_hash_ctx(hdesc->tfm);
    struct shash_desc *desc = *descp;

    desc->flags = hdesc->flags;

    return crypto_shash_init(desc);
}

static int shash_compat_update(struct hash_desc *hdesc, struct scatterlist *sg,
                   unsigned int len)
{
    struct shash_desc **descp = crypto_hash_ctx(hdesc->tfm);
    struct shash_desc *desc = *descp;
    struct crypto_hash_walk walk;
    int nbytes;

    for (nbytes = crypto_hash_walk_first_compat(hdesc, &walk, sg, len);
         nbytes > 0; nbytes = crypto_hash_walk_done(&walk, nbytes))
        nbytes = crypto_shash_update(desc, walk.data, nbytes);

    return nbytes;
}

static int shash_compat_final(struct hash_desc *hdesc, u8 *out)
{
    struct shash_desc **descp = crypto_hash_ctx(hdesc->tfm);

    return crypto_shash_final(*descp, out);
}

static int shash_compat_digest(struct hash_desc *hdesc, struct scatterlist *sg,
                   unsigned int nbytes, u8 *out)
{
    unsigned int offset = sg->offset;
    int err;

    if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
        struct shash_desc **descp = crypto_hash_ctx(hdesc->tfm);
        struct shash_desc *desc = *descp;
        void *data;

        desc->flags = hdesc->flags;

        data = kmap_atomic(sg_page(sg));
        err = crypto_shash_digest(desc, data + offset, nbytes, out);
        kunmap_atomic(data);
        crypto_yield(desc->flags);
        goto out;
    }

    err = shash_compat_init(hdesc);
    if (err)
        goto out;

    err = shash_compat_update(hdesc, sg, nbytes);
    if (err)
        goto out;

    err = shash_compat_final(hdesc, out);

out:
    return err;
}

static void crypto_exit_shash_ops_compat(struct crypto_tfm *tfm)
{
    struct shash_desc **descp = crypto_tfm_ctx(tfm);
    struct shash_desc *desc = *descp;

    crypto_free_shash(desc->tfm);
    kzfree(desc);
}

static int crypto_init_shash_ops_compat(struct crypto_tfm *tfm)
{
    struct hash_tfm *crt = &tfm->crt_hash;
    struct crypto_alg *calg = tfm->__crt_alg;
    struct shash_alg *alg = __crypto_shash_alg(calg);
    struct shash_desc **descp = crypto_tfm_ctx(tfm);
    struct crypto_shash *shash;
    struct shash_desc *desc;

    if (!crypto_mod_get(calg))
        return -EAGAIN;

    shash = crypto_create_tfm(calg, &crypto_shash_type);
    if (IS_ERR(shash)) {
        crypto_mod_put(calg);
        return PTR_ERR(shash);
    }

    desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(shash),
               GFP_KERNEL);
    if (!desc) {
        crypto_free_shash(shash);
        return -ENOMEM;
    }

    *descp = desc;
    desc->tfm = shash;
    tfm->exit = crypto_exit_shash_ops_compat;

    crt->init = shash_compat_init;
    crt->update = shash_compat_update;
    crt->final  = shash_compat_final;
    crt->digest = shash_compat_digest;
    crt->setkey = shash_compat_setkey;

    crt->digestsize = alg->digestsize;

    return 0;
}

static int crypto_init_shash_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
{
    switch (mask & CRYPTO_ALG_TYPE_MASK) {
    case CRYPTO_ALG_TYPE_HASH_MASK:
        return crypto_init_shash_ops_compat(tfm);
    }

    return -EINVAL;
}

static unsigned int crypto_shash_ctxsize(struct crypto_alg *alg, u32 type,
                     u32 mask)
{
    switch (mask & CRYPTO_ALG_TYPE_MASK) {
    case CRYPTO_ALG_TYPE_HASH_MASK:
        return sizeof(struct shash_desc *);
    }

    return 0;
}

static int crypto_shash_init_tfm(struct crypto_tfm *tfm)
{
    struct crypto_shash *hash = __crypto_shash_cast(tfm);

    hash->descsize = crypto_shash_alg(hash)->descsize;
    return 0;
}

static unsigned int crypto_shash_extsize(struct crypto_alg *alg)
{
    return alg->cra_ctxsize;
}

#ifdef CONFIG_NET
static int crypto_shash_report(struct sk_buff *skb, struct crypto_alg *alg)
{
    struct crypto_report_hash rhash;
    struct shash_alg *salg = __crypto_shash_alg(alg);

    snprintf(rhash.type, CRYPTO_MAX_ALG_NAME, "%s", "shash");
    rhash.blocksize = alg->cra_blocksize;
    rhash.digestsize = salg->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_shash_report(struct sk_buff *skb, struct crypto_alg *alg)
{
    return -ENOSYS;
}
#endif

static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
    __attribute__ ((unused));
static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
{
    struct shash_alg *salg = __crypto_shash_alg(alg);

    seq_printf(m, "type         : shash\n");
    seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
    seq_printf(m, "digestsize   : %u\n", salg->digestsize);
}

static const struct crypto_type crypto_shash_type = {
    .ctxsize = crypto_shash_ctxsize,
    .extsize = crypto_shash_extsize,
    .init = crypto_init_shash_ops,
    .init_tfm = crypto_shash_init_tfm,
#ifdef CONFIG_PROC_FS
    .show = crypto_shash_show,
#endif
    .report = crypto_shash_report,
    .maskclear = ~CRYPTO_ALG_TYPE_MASK,
    .maskset = CRYPTO_ALG_TYPE_MASK,
    .type = CRYPTO_ALG_TYPE_SHASH,
    .tfmsize = offsetof(struct crypto_shash, base),
};

struct crypto_shash *crypto_alloc_shash(const char *alg_name, u32 type,
                    u32 mask)
{
    return crypto_alloc_tfm(alg_name, &crypto_shash_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_shash);

static int shash_prepare_alg(struct shash_alg *alg)
{
    struct crypto_alg *base = &alg->base;

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

    base->cra_type = &crypto_shash_type;
    base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
    base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;

    if (!alg->finup)
        alg->finup = shash_finup_unaligned;
    if (!alg->digest)
        alg->digest = shash_digest_unaligned;
    if (!alg->export) {
        alg->export = shash_default_export;
        alg->import = shash_default_import;
        alg->statesize = alg->descsize;
    }
    if (!alg->setkey)
        alg->setkey = shash_no_setkey;

    return 0;
}

int crypto_register_shash(struct shash_alg *alg)
{
    struct crypto_alg *base = &alg->base;
    int err;

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

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

int crypto_unregister_shash(struct shash_alg *alg)
{
    return crypto_unregister_alg(&alg->base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_shash);

int crypto_register_shashes(struct shash_alg *algs, int count)
{
    int i, ret;

    for (i = 0; i < count; i++) {
        ret = crypto_register_shash(&algs[i]);
        if (ret)
            goto err;
    }

    return 0;

err:
    for (--i; i >= 0; --i)
        crypto_unregister_shash(&algs[i]);

    return ret;
}
EXPORT_SYMBOL_GPL(crypto_register_shashes);

int crypto_unregister_shashes(struct shash_alg *algs, int count)
{
    int i, ret;

    for (i = count - 1; i >= 0; --i) {
        ret = crypto_unregister_shash(&algs[i]);
        if (ret)
            pr_err("Failed to unregister %s %s: %d\n",
                   algs[i].base.cra_driver_name,
                   algs[i].base.cra_name, ret);
    }

    return 0;
}
EXPORT_SYMBOL_GPL(crypto_unregister_shashes);

int shash_register_instance(struct crypto_template *tmpl,
                struct shash_instance *inst)
{
    int err;

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

    return crypto_register_instance(tmpl, shash_crypto_instance(inst));
}
EXPORT_SYMBOL_GPL(shash_register_instance);

void shash_free_instance(struct crypto_instance *inst)
{
    crypto_drop_spawn(crypto_instance_ctx(inst));
    kfree(shash_instance(inst));
}
EXPORT_SYMBOL_GPL(shash_free_instance);

int crypto_init_shash_spawn(struct crypto_shash_spawn *spawn,
                struct shash_alg *alg,
                struct crypto_instance *inst)
{
    return crypto_init_spawn2(&spawn->base, &alg->base, inst,
                  &crypto_shash_type);
}
EXPORT_SYMBOL_GPL(crypto_init_shash_spawn);

struct shash_alg *shash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
{
    struct crypto_alg *alg;

    alg = crypto_attr_alg2(rta, &crypto_shash_type, type, mask);
    return IS_ERR(alg) ? ERR_CAST(alg) :
           container_of(alg, struct shash_alg, base);
}
EXPORT_SYMBOL_GPL(shash_attr_alg);

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