// 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 <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 <linux/compiler.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;
}

/*
 * Check whether an shash algorithm has a setkey function.
 *
 * For CFI compatibility, this must not be an inline function.  This is because
 * when CFI is enabled, modules won't get the same address for shash_no_setkey
 * (if it were exported, which inlining would require) as the core kernel will.
 */
bool crypto_shash_alg_has_setkey(struct shash_alg *alg)
{
        return alg->setkey != shash_no_setkey;
}
EXPORT_SYMBOL_GPL(crypto_shash_alg_has_setkey);

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_ATOMIC);
        if (!buffer)
                return -ENOMEM;

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

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);
        unsigned long alignmask = crypto_shash_alignmask(tfm);
        int err;

        if ((unsigned long)key & alignmask)
                err = shash_setkey_unaligned(tfm, key, keylen);
        else
                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 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);
        /*
         * We cannot count on __aligned() working for large values:
         * https://patchwork.kernel.org/patch/9507697/
         */
        u8 ubuf[MAX_ALGAPI_ALIGNMASK * 2];
        u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1);
        int err;

        if (WARN_ON(buf + unaligned_len > ubuf + sizeof(ubuf)))
                return -EINVAL;

        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);
        /*
         * We cannot count on __aligned() working for large values:
         * https://patchwork.kernel.org/patch/9507697/
         */
        u8 ubuf[MAX_ALGAPI_ALIGNMASK + HASH_MAX_DIGESTSIZE];
        u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1);
        int err;

        if (WARN_ON(buf + ds > ubuf + sizeof(ubuf)))
                return -EINVAL;

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

        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);

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

        desc->tfm = tfm;

        err = crypto_shash_digest(desc, data, len, out);

        shash_desc_zero(desc);

        return err;
}
EXPORT_SYMBOL_GPL(crypto_shash_tfm_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;

        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;

        return shash_ahash_finup(req, desc);
}

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_atomic(sg_page(sg));
                err = crypto_shash_digest(desc, data + offset, nbytes,
                                          req->result);
                kunmap_atomic(data);
        } 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;

        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;

        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 (crypto_shash_alg_has_setkey(alg))
                crt->setkey = shash_async_setkey;

        crypto_ahash_set_flags(crt, crypto_shash_get_flags(shash) &
                                    CRYPTO_TFM_NEED_KEY);

        crt->export = shash_async_export;
        crt->import = shash_async_import;

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

        return 0;
}

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);
        int err;

        hash->descsize = alg->descsize;

        shash_set_needkey(hash, alg);

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

        if (!alg->init_tfm)
                return 0;

        err = alg->init_tfm(hash);
        if (err)
                return err;

        /* ->init_tfm() may have increased the descsize. */
        if (WARN_ON_ONCE(hash->descsize > HASH_MAX_DESCSIZE)) {
                if (alg->exit_tfm)
                        alg->exit_tfm(hash);
                return -EINVAL;
        }

        return 0;
}

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

        shash->free(shash);
}

#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);

        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);
}
#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)
        __maybe_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 = {
        .extsize = crypto_alg_extsize,
        .init_tfm = crypto_shash_init_tfm,
        .free = crypto_shash_free_instance,
#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),
};

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);

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

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

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

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)
                        goto err;
        }

        return 0;

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

        return ret;
}
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");