root/crypto/aead.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * AEAD: Authenticated Encryption with Associated Data
 *
 * This file provides API support for AEAD algorithms.
 *
 * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
 */

#include <crypto/internal/aead.h>
#include <linux/cryptouser.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/string_choices.h>
#include <net/netlink.h>

#include "internal.h"

static int setkey_unaligned(struct crypto_aead *tfm, const u8 *key,
                            unsigned int keylen)
{
        unsigned long alignmask = crypto_aead_alignmask(tfm);
        int ret;
        u8 *buffer, *alignbuffer;
        unsigned long absize;

        absize = keylen + alignmask;
        buffer = kmalloc(absize, GFP_ATOMIC);
        if (!buffer)
                return -ENOMEM;

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

int crypto_aead_setkey(struct crypto_aead *tfm,
                       const u8 *key, unsigned int keylen)
{
        unsigned long alignmask = crypto_aead_alignmask(tfm);
        int err;

        if ((unsigned long)key & alignmask)
                err = setkey_unaligned(tfm, key, keylen);
        else
                err = crypto_aead_alg(tfm)->setkey(tfm, key, keylen);

        if (unlikely(err)) {
                crypto_aead_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
                return err;
        }

        crypto_aead_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
        return 0;
}
EXPORT_SYMBOL_GPL(crypto_aead_setkey);

int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
{
        int err;

        if ((!authsize && crypto_aead_maxauthsize(tfm)) ||
            authsize > crypto_aead_maxauthsize(tfm))
                return -EINVAL;

        if (crypto_aead_alg(tfm)->setauthsize) {
                err = crypto_aead_alg(tfm)->setauthsize(tfm, authsize);
                if (err)
                        return err;
        }

        tfm->authsize = authsize;
        return 0;
}
EXPORT_SYMBOL_GPL(crypto_aead_setauthsize);

int crypto_aead_encrypt(struct aead_request *req)
{
        struct crypto_aead *aead = crypto_aead_reqtfm(req);

        if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY)
                return -ENOKEY;

        return crypto_aead_alg(aead)->encrypt(req);
}
EXPORT_SYMBOL_GPL(crypto_aead_encrypt);

int crypto_aead_decrypt(struct aead_request *req)
{
        struct crypto_aead *aead = crypto_aead_reqtfm(req);

        if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY)
                return -ENOKEY;

        if (req->cryptlen < crypto_aead_authsize(aead))
                return -EINVAL;

        return crypto_aead_alg(aead)->decrypt(req);
}
EXPORT_SYMBOL_GPL(crypto_aead_decrypt);

static void crypto_aead_exit_tfm(struct crypto_tfm *tfm)
{
        struct crypto_aead *aead = __crypto_aead_cast(tfm);
        struct aead_alg *alg = crypto_aead_alg(aead);

        alg->exit(aead);
}

static int crypto_aead_init_tfm(struct crypto_tfm *tfm)
{
        struct crypto_aead *aead = __crypto_aead_cast(tfm);
        struct aead_alg *alg = crypto_aead_alg(aead);

        crypto_aead_set_flags(aead, CRYPTO_TFM_NEED_KEY);
        crypto_aead_set_reqsize(aead, crypto_tfm_alg_reqsize(tfm));

        aead->authsize = alg->maxauthsize;

        if (alg->exit)
                aead->base.exit = crypto_aead_exit_tfm;

        if (alg->init)
                return alg->init(aead);

        return 0;
}

static int __maybe_unused crypto_aead_report(
        struct sk_buff *skb, struct crypto_alg *alg)
{
        struct crypto_report_aead raead;
        struct aead_alg *aead = container_of(alg, struct aead_alg, base);

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

        strscpy(raead.type, "aead", sizeof(raead.type));
        strscpy(raead.geniv, "<none>", sizeof(raead.geniv));

        raead.blocksize = alg->cra_blocksize;
        raead.maxauthsize = aead->maxauthsize;
        raead.ivsize = aead->ivsize;

        return nla_put(skb, CRYPTOCFGA_REPORT_AEAD, sizeof(raead), &raead);
}

static void __maybe_unused crypto_aead_show(struct seq_file *m,
                                            struct crypto_alg *alg)
{
        struct aead_alg *aead = container_of(alg, struct aead_alg, base);

        seq_printf(m, "type         : aead\n");
        seq_printf(m, "async        : %s\n",
                   str_yes_no(alg->cra_flags & CRYPTO_ALG_ASYNC));
        seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
        seq_printf(m, "ivsize       : %u\n", aead->ivsize);
        seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
        seq_printf(m, "geniv        : <none>\n");
}

static void crypto_aead_free_instance(struct crypto_instance *inst)
{
        struct aead_instance *aead = aead_instance(inst);

        aead->free(aead);
}

static const struct crypto_type crypto_aead_type = {
        .extsize = crypto_alg_extsize,
        .init_tfm = crypto_aead_init_tfm,
        .free = crypto_aead_free_instance,
#ifdef CONFIG_PROC_FS
        .show = crypto_aead_show,
#endif
#if IS_ENABLED(CONFIG_CRYPTO_USER)
        .report = crypto_aead_report,
#endif
        .maskclear = ~CRYPTO_ALG_TYPE_MASK,
        .maskset = CRYPTO_ALG_TYPE_MASK,
        .type = CRYPTO_ALG_TYPE_AEAD,
        .tfmsize = offsetof(struct crypto_aead, base),
        .algsize = offsetof(struct aead_alg, base),
};

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

struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask)
{
        return crypto_alloc_tfm(alg_name, &crypto_aead_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_aead);

struct crypto_sync_aead *crypto_alloc_sync_aead(const char *alg_name, u32 type, u32 mask)
{
        struct crypto_aead *tfm;

        /* Only sync algorithms are allowed. */
        mask |= CRYPTO_ALG_ASYNC;
        type &= ~(CRYPTO_ALG_ASYNC);

        tfm = crypto_alloc_tfm(alg_name, &crypto_aead_type, type, mask);

        if (!IS_ERR(tfm) && WARN_ON(crypto_aead_reqsize(tfm) > MAX_SYNC_AEAD_REQSIZE)) {
                crypto_free_aead(tfm);
                return ERR_PTR(-EINVAL);
        }

        return (struct crypto_sync_aead *)tfm;
}
EXPORT_SYMBOL_GPL(crypto_alloc_sync_aead);

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

static int aead_prepare_alg(struct aead_alg *alg)
{
        struct crypto_alg *base = &alg->base;

        if (max3(alg->maxauthsize, alg->ivsize, alg->chunksize) >
            PAGE_SIZE / 8)
                return -EINVAL;

        if (!alg->chunksize)
                alg->chunksize = base->cra_blocksize;

        base->cra_type = &crypto_aead_type;
        base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
        base->cra_flags |= CRYPTO_ALG_TYPE_AEAD;

        return 0;
}

int crypto_register_aead(struct aead_alg *alg)
{
        struct crypto_alg *base = &alg->base;
        int err;

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

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

void crypto_unregister_aead(struct aead_alg *alg)
{
        crypto_unregister_alg(&alg->base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_aead);

int crypto_register_aeads(struct aead_alg *algs, int count)
{
        int i, ret;

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

        return 0;

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

        return ret;
}
EXPORT_SYMBOL_GPL(crypto_register_aeads);

void crypto_unregister_aeads(struct aead_alg *algs, int count)
{
        int i;

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

int aead_register_instance(struct crypto_template *tmpl,
                           struct aead_instance *inst)
{
        int err;

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

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

        return crypto_register_instance(tmpl, aead_crypto_instance(inst));
}
EXPORT_SYMBOL_GPL(aead_register_instance);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Authenticated Encryption with Associated Data (AEAD)");