crypto: ahash - unexport crypto_hash_alg_has_setkey()

[thirdparty/kernel/linux.git] / crypto / ahash.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Asynchronous Cryptographic Hash operations.
 *
 * This is the implementation of the ahash (asynchronous hash) API.  It differs
 * from shash (synchronous hash) in that ahash supports asynchronous operations,
 * and it hashes data from scatterlists instead of virtually addressed buffers.
 *
 * The ahash API provides access to both ahash and shash algorithms.  The shash
 * API only provides access to shash algorithms.
 *
 * Copyright (c) 2008 Loc Ho <lho@amcc.com>
 */

#include <crypto/scatterwalk.h>
#include <linux/cryptouser.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/string.h>
#include <net/netlink.h>

#include "hash.h"

#define CRYPTO_ALG_TYPE_AHASH_MASK      0x0000000e

static inline struct crypto_istat_hash *ahash_get_stat(struct ahash_alg *alg)
{
        return hash_get_stat(&alg->halg);
}

static inline int crypto_ahash_errstat(struct ahash_alg *alg, int err)
{
        if (!IS_ENABLED(CONFIG_CRYPTO_STATS))
                return err;

        if (err && err != -EINPROGRESS && err != -EBUSY)
                atomic64_inc(&ahash_get_stat(alg)->err_cnt);

        return err;
}

/*
 * For an ahash tfm that is using an shash algorithm (instead of an ahash
 * algorithm), this returns the underlying shash tfm.
 */
static inline struct crypto_shash *ahash_to_shash(struct crypto_ahash *tfm)
{
        return *(struct crypto_shash **)crypto_ahash_ctx(tfm);
}

static inline struct shash_desc *prepare_shash_desc(struct ahash_request *req,
                                                    struct crypto_ahash *tfm)
{
        struct shash_desc *desc = ahash_request_ctx(req);

        desc->tfm = ahash_to_shash(tfm);
        return 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);

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);

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

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

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

        return err;
}
EXPORT_SYMBOL_GPL(shash_ahash_digest);

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

        crypto_free_shash(*ctx);
}

static int crypto_init_ahash_using_shash(struct crypto_tfm *tfm)
{
        struct crypto_alg *calg = tfm->__crt_alg;
        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);
        }

        crt->using_shash = true;
        *ctx = shash;
        tfm->exit = crypto_exit_ahash_using_shash;

        crypto_ahash_set_flags(crt, crypto_shash_get_flags(shash) &
                                    CRYPTO_TFM_NEED_KEY);
        crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);

        return 0;
}

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

        walk->data = kmap_local_page(walk->pg);
        walk->data += offset;
        walk->entrylen -= nbytes;
        return nbytes;
}

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

        sg = walk->sg;
        walk->offset = sg->offset;
        walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
        walk->offset = offset_in_page(walk->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)
{
        walk->data -= walk->offset;

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

        if (err)
                return err;

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

        if (!walk->total)
                return 0;

        walk->sg = 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) {
                walk->entrylen = 0;
                return 0;
        }

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

static void ahash_set_needkey(struct crypto_ahash *tfm, struct ahash_alg *alg)
{
        if (alg->setkey != ahash_nosetkey &&
            !(alg->halg.base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
                crypto_ahash_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
}

int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
                        unsigned int keylen)
{
        if (likely(tfm->using_shash)) {
                struct crypto_shash *shash = ahash_to_shash(tfm);
                int err;

                err = crypto_shash_setkey(shash, key, keylen);
                if (unlikely(err)) {
                        crypto_ahash_set_flags(tfm,
                                               crypto_shash_get_flags(shash) &
                                               CRYPTO_TFM_NEED_KEY);
                        return err;
                }
        } else {
                struct ahash_alg *alg = crypto_ahash_alg(tfm);
                int err;

                err = alg->setkey(tfm, key, keylen);
                if (unlikely(err)) {
                        ahash_set_needkey(tfm, alg);
                        return err;
                }
        }
        crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
        return 0;
}
EXPORT_SYMBOL_GPL(crypto_ahash_setkey);

int crypto_ahash_init(struct ahash_request *req)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);

        if (likely(tfm->using_shash))
                return crypto_shash_init(prepare_shash_desc(req, tfm));
        if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
                return -ENOKEY;
        return crypto_ahash_alg(tfm)->init(req);
}
EXPORT_SYMBOL_GPL(crypto_ahash_init);

static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt,
                          bool has_state)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
        unsigned int ds = crypto_ahash_digestsize(tfm);
        struct ahash_request *subreq;
        unsigned int subreq_size;
        unsigned int reqsize;
        u8 *result;
        gfp_t gfp;
        u32 flags;

        subreq_size = sizeof(*subreq);
        reqsize = crypto_ahash_reqsize(tfm);
        reqsize = ALIGN(reqsize, crypto_tfm_ctx_alignment());
        subreq_size += reqsize;
        subreq_size += ds;

        flags = ahash_request_flags(req);
        gfp = (flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?  GFP_KERNEL : GFP_ATOMIC;
        subreq = kmalloc(subreq_size, gfp);
        if (!subreq)
                return -ENOMEM;

        ahash_request_set_tfm(subreq, tfm);
        ahash_request_set_callback(subreq, flags, cplt, req);

        result = (u8 *)(subreq + 1) + reqsize;

        ahash_request_set_crypt(subreq, req->src, result, req->nbytes);

        if (has_state) {
                void *state;

                state = kmalloc(crypto_ahash_statesize(tfm), gfp);
                if (!state) {
                        kfree(subreq);
                        return -ENOMEM;
                }

                crypto_ahash_export(req, state);
                crypto_ahash_import(subreq, state);
                kfree_sensitive(state);
        }

        req->priv = subreq;

        return 0;
}

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

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

        req->priv = NULL;

        kfree_sensitive(subreq);
}

int crypto_ahash_update(struct ahash_request *req)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
        struct ahash_alg *alg;

        if (likely(tfm->using_shash))
                return shash_ahash_update(req, ahash_request_ctx(req));

        alg = crypto_ahash_alg(tfm);
        if (IS_ENABLED(CONFIG_CRYPTO_STATS))
                atomic64_add(req->nbytes, &ahash_get_stat(alg)->hash_tlen);
        return crypto_ahash_errstat(alg, alg->update(req));
}
EXPORT_SYMBOL_GPL(crypto_ahash_update);

int crypto_ahash_final(struct ahash_request *req)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
        struct ahash_alg *alg;

        if (likely(tfm->using_shash))
                return crypto_shash_final(ahash_request_ctx(req), req->result);

        alg = crypto_ahash_alg(tfm);
        if (IS_ENABLED(CONFIG_CRYPTO_STATS))
                atomic64_inc(&ahash_get_stat(alg)->hash_cnt);
        return crypto_ahash_errstat(alg, alg->final(req));
}
EXPORT_SYMBOL_GPL(crypto_ahash_final);

int crypto_ahash_finup(struct ahash_request *req)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
        struct ahash_alg *alg;

        if (likely(tfm->using_shash))
                return shash_ahash_finup(req, ahash_request_ctx(req));

        alg = crypto_ahash_alg(tfm);
        if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
                struct crypto_istat_hash *istat = ahash_get_stat(alg);

                atomic64_inc(&istat->hash_cnt);
                atomic64_add(req->nbytes, &istat->hash_tlen);
        }
        return crypto_ahash_errstat(alg, alg->finup(req));
}
EXPORT_SYMBOL_GPL(crypto_ahash_finup);

int crypto_ahash_digest(struct ahash_request *req)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
        struct ahash_alg *alg;
        int err;

        if (likely(tfm->using_shash))
                return shash_ahash_digest(req, prepare_shash_desc(req, tfm));

        alg = crypto_ahash_alg(tfm);
        if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
                struct crypto_istat_hash *istat = ahash_get_stat(alg);

                atomic64_inc(&istat->hash_cnt);
                atomic64_add(req->nbytes, &istat->hash_tlen);
        }

        if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
                err = -ENOKEY;
        else
                err = alg->digest(req);

        return crypto_ahash_errstat(alg, err);
}
EXPORT_SYMBOL_GPL(crypto_ahash_digest);

static void ahash_def_finup_done2(void *data, int err)
{
        struct ahash_request *areq = data;

        if (err == -EINPROGRESS)
                return;

        ahash_restore_req(areq, err);

        ahash_request_complete(areq, err);
}

static int ahash_def_finup_finish1(struct ahash_request *req, int err)
{
        struct ahash_request *subreq = req->priv;

        if (err)
                goto out;

        subreq->base.complete = ahash_def_finup_done2;

        err = crypto_ahash_alg(crypto_ahash_reqtfm(req))->final(subreq);
        if (err == -EINPROGRESS || err == -EBUSY)
                return err;

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

static void ahash_def_finup_done1(void *data, int err)
{
        struct ahash_request *areq = data;
        struct ahash_request *subreq;

        if (err == -EINPROGRESS)
                goto out;

        subreq = areq->priv;
        subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;

        err = ahash_def_finup_finish1(areq, err);
        if (err == -EINPROGRESS || err == -EBUSY)
                return;

out:
        ahash_request_complete(areq, err);
}

static int ahash_def_finup(struct ahash_request *req)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
        int err;

        err = ahash_save_req(req, ahash_def_finup_done1, true);
        if (err)
                return err;

        err = crypto_ahash_alg(tfm)->update(req->priv);
        if (err == -EINPROGRESS || err == -EBUSY)
                return err;

        return ahash_def_finup_finish1(req, err);
}

int crypto_ahash_export(struct ahash_request *req, void *out)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);

        if (likely(tfm->using_shash))
                return crypto_shash_export(ahash_request_ctx(req), out);
        return crypto_ahash_alg(tfm)->export(req, out);
}
EXPORT_SYMBOL_GPL(crypto_ahash_export);

int crypto_ahash_import(struct ahash_request *req, const void *in)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);

        if (likely(tfm->using_shash))
                return crypto_shash_import(prepare_shash_desc(req, tfm), in);
        if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
                return -ENOKEY;
        return crypto_ahash_alg(tfm)->import(req, in);
}
EXPORT_SYMBOL_GPL(crypto_ahash_import);

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

        alg->exit_tfm(hash);
}

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);

        crypto_ahash_set_statesize(hash, alg->halg.statesize);

        if (tfm->__crt_alg->cra_type == &crypto_shash_type)
                return crypto_init_ahash_using_shash(tfm);

        ahash_set_needkey(hash, alg);

        if (alg->exit_tfm)
                tfm->exit = crypto_ahash_exit_tfm;

        return alg->init_tfm ? alg->init_tfm(hash) : 0;
}

static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
{
        if (alg->cra_type == &crypto_shash_type)
                return sizeof(struct crypto_shash *);

        return crypto_alg_extsize(alg);
}

static void crypto_ahash_free_instance(struct crypto_instance *inst)
{
        struct ahash_instance *ahash = ahash_instance(inst);

        ahash->free(ahash);
}

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

        memset(&rhash, 0, sizeof(rhash));

        strscpy(rhash.type, "ahash", sizeof(rhash.type));

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

        return nla_put(skb, CRYPTOCFGA_REPORT_HASH, sizeof(rhash), &rhash);
}

static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
        __maybe_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);
}

static int __maybe_unused crypto_ahash_report_stat(
        struct sk_buff *skb, struct crypto_alg *alg)
{
        return crypto_hash_report_stat(skb, alg, "ahash");
}

static const struct crypto_type crypto_ahash_type = {
        .extsize = crypto_ahash_extsize,
        .init_tfm = crypto_ahash_init_tfm,
        .free = crypto_ahash_free_instance,
#ifdef CONFIG_PROC_FS
        .show = crypto_ahash_show,
#endif
#if IS_ENABLED(CONFIG_CRYPTO_USER)
        .report = crypto_ahash_report,
#endif
#ifdef CONFIG_CRYPTO_STATS
        .report_stat = crypto_ahash_report_stat,
#endif
        .maskclear = ~CRYPTO_ALG_TYPE_MASK,
        .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
        .type = CRYPTO_ALG_TYPE_AHASH,
        .tfmsize = offsetof(struct crypto_ahash, base),
};

int crypto_grab_ahash(struct crypto_ahash_spawn *spawn,
                      struct crypto_instance *inst,
                      const char *name, u32 type, u32 mask)
{
        spawn->base.frontend = &crypto_ahash_type;
        return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_grab_ahash);

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);

int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
{
        return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_has_ahash);

static bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
{
        struct crypto_alg *alg = &halg->base;

        if (alg->cra_type == &crypto_shash_type)
                return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));

        return __crypto_ahash_alg(alg)->setkey != ahash_nosetkey;
}

struct crypto_ahash *crypto_clone_ahash(struct crypto_ahash *hash)
{
        struct hash_alg_common *halg = crypto_hash_alg_common(hash);
        struct crypto_tfm *tfm = crypto_ahash_tfm(hash);
        struct crypto_ahash *nhash;
        struct ahash_alg *alg;
        int err;

        if (!crypto_hash_alg_has_setkey(halg)) {
                tfm = crypto_tfm_get(tfm);
                if (IS_ERR(tfm))
                        return ERR_CAST(tfm);

                return hash;
        }

        nhash = crypto_clone_tfm(&crypto_ahash_type, tfm);

        if (IS_ERR(nhash))
                return nhash;

        nhash->reqsize = hash->reqsize;
        nhash->statesize = hash->statesize;

        if (likely(hash->using_shash)) {
                struct crypto_shash **nctx = crypto_ahash_ctx(nhash);
                struct crypto_shash *shash;

                shash = crypto_clone_shash(ahash_to_shash(hash));
                if (IS_ERR(shash)) {
                        err = PTR_ERR(shash);
                        goto out_free_nhash;
                }
                nhash->using_shash = true;
                *nctx = shash;
                return nhash;
        }

        err = -ENOSYS;
        alg = crypto_ahash_alg(hash);
        if (!alg->clone_tfm)
                goto out_free_nhash;

        err = alg->clone_tfm(nhash, hash);
        if (err)
                goto out_free_nhash;

        return nhash;

out_free_nhash:
        crypto_free_ahash(nhash);
        return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(crypto_clone_ahash);

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

        if (alg->halg.statesize == 0)
                return -EINVAL;

        err = hash_prepare_alg(&alg->halg);
        if (err)
                return err;

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

        if (!alg->finup)
                alg->finup = ahash_def_finup;
        if (!alg->setkey)
                alg->setkey = ahash_nosetkey;

        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);

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

int crypto_register_ahashes(struct ahash_alg *algs, int count)
{
        int i, ret;

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

        return 0;

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

        return ret;
}
EXPORT_SYMBOL_GPL(crypto_register_ahashes);

void crypto_unregister_ahashes(struct ahash_alg *algs, int count)
{
        int i;

        for (i = count - 1; i >= 0; --i)
                crypto_unregister_ahash(&algs[i]);
}
EXPORT_SYMBOL_GPL(crypto_unregister_ahashes);

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

        if (WARN_ON(!inst->free))
                return -EINVAL;

        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);

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