crypto: shash - Move finup/digest null checks to registration time

[mirror_ubuntu-bionic-kernel.git] / crypto / shash.c

/*
 * Synchronous Cryptographic Hash operations.
 *
 * Copyright (c) 2008 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/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 "internal.h"

static const struct crypto_type crypto_shash_type;

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_MINALIGN - 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);
        memset(alignbuffer, 0, keylen);
        kfree(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 (!shash->setkey)
                return -ENOSYS;

        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 buf[shash_align_buffer_size(unaligned_len, alignmask)]
                __attribute__ ((aligned));

        if (unaligned_len > len)
                unaligned_len = len;

        memcpy(buf, data, unaligned_len);

        return shash->update(desc, buf, unaligned_len) ?:
               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 buf[shash_align_buffer_size(ds, alignmask)]
                __attribute__ ((aligned));
        int err;

        err = shash->final(desc, buf);
        memcpy(out, buf, 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_no_export(struct shash_desc *desc, void *out)
{
        return -ENOSYS;
}

static int shash_no_import(struct shash_desc *desc, const void *in)
{
        return -ENOSYS;
}

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);
}

static int shash_async_update(struct ahash_request *req)
{
        struct shash_desc *desc = ahash_request_ctx(req);
        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;
}

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

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

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

                data = crypto_kmap(sg_page(sg), 0);
                err = crypto_shash_digest(desc, data + offset, nbytes,
                                          req->result);
                crypto_kunmap(data, 0);
                crypto_yield(desc->flags);
                goto out;
        }

        err = shash_async_init(req);
        if (err)
                goto out;

        err = shash_async_update(req);
        if (err)
                goto out;

        err = shash_async_final(req);

out:
        return err;
}

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

        crypto_free_shash(*ctx);
}

static 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 ahash_tfm *crt = &tfm->crt_ahash;
        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->digest = shash_async_digest;
        crt->setkey = shash_async_setkey;

        crt->digestsize = alg->digestsize;
        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 *desc = crypto_hash_ctx(tfm);

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

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

        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 *desc = crypto_hash_ctx(hdesc->tfm);
        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)
{
        return crypto_shash_final(crypto_hash_ctx(hdesc->tfm), 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 *desc = crypto_hash_ctx(hdesc->tfm);
                void *data;

                desc->flags = hdesc->flags;

                data = crypto_kmap(sg_page(sg), 0);
                err = crypto_shash_digest(desc, data + offset, nbytes, out);
                crypto_kunmap(data, 0);
                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 *desc= crypto_tfm_ctx(tfm);

        crypto_free_shash(desc->tfm);
}

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 *desc = 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);
        }

        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);
        case CRYPTO_ALG_TYPE_AHASH_MASK:
                return crypto_init_shash_ops_async(tfm);
        }

        return -EINVAL;
}

static unsigned int crypto_shash_ctxsize(struct crypto_alg *alg, u32 type,
                                         u32 mask)
{
        struct shash_alg *salg = __crypto_shash_alg(alg);

        switch (mask & CRYPTO_ALG_TYPE_MASK) {
        case CRYPTO_ALG_TYPE_HASH_MASK:
                return sizeof(struct shash_desc) + salg->descsize;
        case CRYPTO_ALG_TYPE_AHASH_MASK:
                return sizeof(struct crypto_shash *);
        }

        return 0;
}

static int crypto_shash_init_tfm(struct crypto_tfm *tfm,
                                 const struct crypto_type *frontend)
{
        return 0;
}

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

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);
        seq_printf(m, "descsize     : %u\n", salg->descsize);
}

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
        .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->import)
                alg->import = shash_no_import;
        if (!alg->export)
                alg->export = shash_no_export;

        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 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");