// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Synchronous Cryptographic Hash operations.
 *
 * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
 */

#include <crypto/scatterwalk.h>
#include <linux/cryptouser.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <net/netlink.h>

#include "hash.h"

static inline bool crypto_shash_block_only(struct crypto_shash *tfm)
{
        return crypto_shash_alg(tfm)->base.cra_flags &
               CRYPTO_AHASH_ALG_BLOCK_ONLY;
}

static inline bool crypto_shash_final_nonzero(struct crypto_shash *tfm)
{
        return crypto_shash_alg(tfm)->base.cra_flags &
               CRYPTO_AHASH_ALG_FINAL_NONZERO;
}

static inline bool crypto_shash_finup_max(struct crypto_shash *tfm)
{
        return crypto_shash_alg(tfm)->base.cra_flags &
               CRYPTO_AHASH_ALG_FINUP_MAX;
}

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

static void shash_set_needkey(struct crypto_shash *tfm, struct shash_alg *alg)
{
        if (crypto_shash_alg_needs_key(alg))
                crypto_shash_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
}

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

        err = shash->setkey(tfm, key, keylen);
        if (unlikely(err)) {
                shash_set_needkey(tfm, shash);
                return err;
        }

        crypto_shash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
        return 0;
}
EXPORT_SYMBOL_GPL(crypto_shash_setkey);

static int __crypto_shash_init(struct shash_desc *desc)
{
        struct crypto_shash *tfm = desc->tfm;

        if (crypto_shash_block_only(tfm)) {
                u8 *buf = shash_desc_ctx(desc);

                buf += crypto_shash_descsize(tfm) - 1;
                *buf = 0;
        }

        return crypto_shash_alg(tfm)->init(desc);
}

int crypto_shash_init(struct shash_desc *desc)
{
        if (crypto_shash_get_flags(desc->tfm) & CRYPTO_TFM_NEED_KEY)
                return -ENOKEY;
        return __crypto_shash_init(desc);
}
EXPORT_SYMBOL_GPL(crypto_shash_init);

static int shash_default_finup(struct shash_desc *desc, const u8 *data,
                               unsigned int len, u8 *out)
{
        struct shash_alg *shash = crypto_shash_alg(desc->tfm);

        return shash->update(desc, data, len) ?:
               shash->final(desc, out);
}

static int crypto_shash_op_and_zero(
        int (*op)(struct shash_desc *desc, const u8 *data,
                  unsigned int len, u8 *out),
        struct shash_desc *desc, const u8 *data, unsigned int len, u8 *out)
{
        int err;

        err = op(desc, data, len, out);
        memset(shash_desc_ctx(desc), 0, crypto_shash_descsize(desc->tfm));
        return err;
}

int crypto_shash_finup(struct shash_desc *restrict desc, const u8 *data,
                       unsigned int len, u8 *restrict out)
{
        struct crypto_shash *tfm = desc->tfm;
        u8 *blenp = shash_desc_ctx(desc);
        bool finup_max, nonzero;
        unsigned int bs;
        int err;
        u8 *buf;

        if (!crypto_shash_block_only(tfm)) {
                if (out)
                        goto finup;
                return crypto_shash_alg(tfm)->update(desc, data, len);
        }

        finup_max = out && crypto_shash_finup_max(tfm);

        /* Retain extra block for final nonzero algorithms. */
        nonzero = crypto_shash_final_nonzero(tfm);

        /*
         * The partial block buffer follows the algorithm desc context.
         * The byte following that contains the length.
         */
        blenp += crypto_shash_descsize(tfm) - 1;
        bs = crypto_shash_blocksize(tfm);
        buf = blenp - bs;

        if (likely(!*blenp && finup_max))
                goto finup;

        while ((*blenp + len) >= bs + nonzero) {
                unsigned int nbytes = len - nonzero;
                const u8 *src = data;

                if (*blenp) {
                        memcpy(buf + *blenp, data, bs - *blenp);
                        nbytes = bs;
                        src = buf;
                }

                err = crypto_shash_alg(tfm)->update(desc, src, nbytes);
                if (err < 0)
                        return err;

                data += nbytes - err - *blenp;
                len -= nbytes - err - *blenp;
                *blenp = 0;
        }

        if (*blenp || !out) {
                memcpy(buf + *blenp, data, len);
                *blenp += len;
                if (!out)
                        return 0;
                data = buf;
                len = *blenp;
        }

finup:
        return crypto_shash_op_and_zero(crypto_shash_alg(tfm)->finup, desc,
                                        data, len, out);
}
EXPORT_SYMBOL_GPL(crypto_shash_finup);

static int shash_default_digest(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;

        if (crypto_shash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
                return -ENOKEY;

        return crypto_shash_op_and_zero(crypto_shash_alg(tfm)->digest, desc,
                                        data, len, out);
}
EXPORT_SYMBOL_GPL(crypto_shash_digest);

int crypto_shash_tfm_digest(struct crypto_shash *tfm, const u8 *data,
                            unsigned int len, u8 *out)
{
        SHASH_DESC_ON_STACK(desc, tfm);

        desc->tfm = tfm;
        return crypto_shash_digest(desc, data, len, out);
}
EXPORT_SYMBOL_GPL(crypto_shash_tfm_digest);

static int __crypto_shash_export(struct shash_desc *desc, void *out,
                                 int (*export)(struct shash_desc *desc,
                                               void *out))
{
        struct crypto_shash *tfm = desc->tfm;
        u8 *buf = shash_desc_ctx(desc);
        unsigned int plen, ss;

        plen = crypto_shash_blocksize(tfm) + 1;
        ss = crypto_shash_statesize(tfm);
        if (crypto_shash_block_only(tfm))
                ss -= plen;
        if (!export) {
                memcpy(out, buf, ss);
                return 0;
        }

        return export(desc, out);
}

int crypto_shash_export_core(struct shash_desc *desc, void *out)
{
        return __crypto_shash_export(desc, out,
                                     crypto_shash_alg(desc->tfm)->export_core);
}
EXPORT_SYMBOL_GPL(crypto_shash_export_core);

int crypto_shash_export(struct shash_desc *desc, void *out)
{
        struct crypto_shash *tfm = desc->tfm;

        if (crypto_shash_block_only(tfm)) {
                unsigned int plen = crypto_shash_blocksize(tfm) + 1;
                unsigned int descsize = crypto_shash_descsize(tfm);
                unsigned int ss = crypto_shash_statesize(tfm);
                u8 *buf = shash_desc_ctx(desc);

                memcpy(out + ss - plen, buf + descsize - plen, plen);
        }
        return __crypto_shash_export(desc, out, crypto_shash_alg(tfm)->export);
}
EXPORT_SYMBOL_GPL(crypto_shash_export);

static int __crypto_shash_import(struct shash_desc *desc, const void *in,
                                 int (*import)(struct shash_desc *desc,
                                               const void *in))
{
        struct crypto_shash *tfm = desc->tfm;
        unsigned int descsize, plen, ss;
        u8 *buf = shash_desc_ctx(desc);

        if (crypto_shash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
                return -ENOKEY;

        ss = crypto_shash_statesize(tfm);
        if (crypto_shash_block_only(tfm)) {
                plen = crypto_shash_blocksize(tfm) + 1;
                ss -= plen;
                descsize = crypto_shash_descsize(tfm);
                buf[descsize - 1] = 0;
        }
        if (!import) {
                memcpy(buf, in, ss);
                return 0;
        }

        return import(desc, in);
}

int crypto_shash_import_core(struct shash_desc *desc, const void *in)
{
        return __crypto_shash_import(desc, in,
                                     crypto_shash_alg(desc->tfm)->import_core);
}
EXPORT_SYMBOL_GPL(crypto_shash_import_core);

int crypto_shash_import(struct shash_desc *desc, const void *in)
{
        struct crypto_shash *tfm = desc->tfm;
        int err;

        err = __crypto_shash_import(desc, in, crypto_shash_alg(tfm)->import);
        if (crypto_shash_block_only(tfm)) {
                unsigned int plen = crypto_shash_blocksize(tfm) + 1;
                unsigned int descsize = crypto_shash_descsize(tfm);
                unsigned int ss = crypto_shash_statesize(tfm);
                u8 *buf = shash_desc_ctx(desc);

                memcpy(buf + descsize - plen, in + ss - plen, plen);
                if (buf[descsize - 1] >= plen)
                        err = -EOVERFLOW;
        }
        return err;
}
EXPORT_SYMBOL_GPL(crypto_shash_import);

static void crypto_shash_exit_tfm(struct crypto_tfm *tfm)
{
        struct crypto_shash *hash = __crypto_shash_cast(tfm);
        struct shash_alg *alg = crypto_shash_alg(hash);

        alg->exit_tfm(hash);
}

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

        shash_set_needkey(hash, alg);

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

        if (!alg->init_tfm)
                return 0;

        return alg->init_tfm(hash);
}

static void crypto_shash_free_instance(struct crypto_instance *inst)
{
        struct shash_instance *shash = shash_instance(inst);

        shash->free(shash);
}

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

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

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

        rhash.blocksize = alg->cra_blocksize;
        rhash.digestsize = salg->digestsize;

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

static void __maybe_unused 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);
}

const struct crypto_type crypto_shash_type = {
        .extsize = crypto_alg_extsize,
        .init_tfm = crypto_shash_init_tfm,
        .free = crypto_shash_free_instance,
#ifdef CONFIG_PROC_FS
        .show = crypto_shash_show,
#endif
#if IS_ENABLED(CONFIG_CRYPTO_USER)
        .report = crypto_shash_report,
#endif
        .maskclear = ~CRYPTO_ALG_TYPE_MASK,
        .maskset = CRYPTO_ALG_TYPE_MASK,
        .type = CRYPTO_ALG_TYPE_SHASH,
        .tfmsize = offsetof(struct crypto_shash, base),
        .algsize = offsetof(struct shash_alg, base),
};

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

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);

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

struct crypto_shash *crypto_clone_shash(struct crypto_shash *hash)
{
        struct crypto_tfm *tfm = crypto_shash_tfm(hash);
        struct shash_alg *alg = crypto_shash_alg(hash);
        struct crypto_shash *nhash;
        int err;

        if (!crypto_shash_alg_has_setkey(alg)) {
                tfm = crypto_tfm_get(tfm);
                if (IS_ERR(tfm))
                        return ERR_CAST(tfm);

                return hash;
        }

        if (!alg->clone_tfm && (alg->init_tfm || alg->base.cra_init))
                return ERR_PTR(-ENOSYS);

        nhash = crypto_clone_tfm(&crypto_shash_type, tfm);
        if (IS_ERR(nhash))
                return nhash;

        if (alg->clone_tfm) {
                err = alg->clone_tfm(nhash, hash);
                if (err) {
                        crypto_free_shash(nhash);
                        return ERR_PTR(err);
                }
        }

        if (alg->exit_tfm)
                crypto_shash_tfm(nhash)->exit = crypto_shash_exit_tfm;

        return nhash;
}
EXPORT_SYMBOL_GPL(crypto_clone_shash);

int hash_prepare_alg(struct hash_alg_common *alg)
{
        struct crypto_alg *base = &alg->base;

        if (alg->digestsize > HASH_MAX_DIGESTSIZE)
                return -EINVAL;

        /* alignmask is not useful for hashes, so it is not supported. */
        if (base->cra_alignmask)
                return -EINVAL;

        base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;

        return 0;
}

static int shash_default_export_core(struct shash_desc *desc, void *out)
{
        return -ENOSYS;
}

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

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

        if ((alg->export && !alg->import) || (alg->import && !alg->export))
                return -EINVAL;

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

        base->cra_type = &crypto_shash_type;
        base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;
        base->cra_flags |= CRYPTO_ALG_REQ_VIRT;

        /*
         * Handle missing optional functions.  For each one we can either
         * install a default here, or we can leave the pointer as NULL and check
         * the pointer for NULL in crypto_shash_*(), avoiding an indirect call
         * when the default behavior is desired.  For ->finup and ->digest we
         * install defaults, since for optimal performance algorithms should
         * implement these anyway.  On the other hand, for ->import and
         * ->export the common case and best performance comes from the simple
         * memcpy of the shash_desc_ctx, so when those pointers are NULL we
         * leave them NULL and provide the memcpy with no indirect call.
         */
        if (!alg->finup)
                alg->finup = shash_default_finup;
        if (!alg->digest)
                alg->digest = shash_default_digest;
        if (!alg->export && !alg->halg.statesize)
                alg->halg.statesize = alg->descsize;
        if (!alg->setkey)
                alg->setkey = shash_no_setkey;

        if (base->cra_flags & CRYPTO_AHASH_ALG_BLOCK_ONLY) {
                BUILD_BUG_ON(MAX_ALGAPI_BLOCKSIZE >= 256);
                alg->descsize += base->cra_blocksize + 1;
                alg->statesize += base->cra_blocksize + 1;
                alg->export_core = alg->export;
                alg->import_core = alg->import;
        } else if (!alg->export_core || !alg->import_core) {
                alg->export_core = shash_default_export_core;
                alg->import_core = shash_default_import_core;
                base->cra_flags |= CRYPTO_AHASH_ALG_NO_EXPORT_CORE;
        }

        if (alg->descsize > HASH_MAX_DESCSIZE)
                return -EINVAL;
        if (alg->statesize > HASH_MAX_STATESIZE)
                return -EINVAL;

        base->cra_reqsize = sizeof(struct shash_desc) + alg->descsize;

        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);

void crypto_unregister_shash(struct shash_alg *alg)
{
        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) {
                        crypto_unregister_shashes(algs, i);
                        return ret;
                }
        }

        return 0;
}
EXPORT_SYMBOL_GPL(crypto_register_shashes);

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

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

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

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

        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_singlespawn_instance(struct shash_instance *inst)
{
        crypto_drop_spawn(shash_instance_ctx(inst));
        kfree(inst);
}
EXPORT_SYMBOL_GPL(shash_free_singlespawn_instance);

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