// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Linear symmetric key cipher operations.
 *
 * Generic encrypt/decrypt wrapper for ciphers.
 *
 * Copyright (c) 2023 Herbert Xu <herbert@gondor.apana.org.au>
 */

#include <linux/cryptouser.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <net/netlink.h>
#include "skcipher.h"

static inline struct crypto_lskcipher *__crypto_lskcipher_cast(
        struct crypto_tfm *tfm)
{
        return container_of(tfm, struct crypto_lskcipher, base);
}

static inline struct lskcipher_alg *__crypto_lskcipher_alg(
        struct crypto_alg *alg)
{
        return container_of(alg, struct lskcipher_alg, co.base);
}

static int lskcipher_setkey_unaligned(struct crypto_lskcipher *tfm,
                                      const u8 *key, unsigned int keylen)
{
        unsigned long alignmask = crypto_lskcipher_alignmask(tfm);
        struct lskcipher_alg *cipher = crypto_lskcipher_alg(tfm);
        u8 *buffer, *alignbuffer;
        unsigned long absize;
        int ret;

        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 = cipher->setkey(tfm, alignbuffer, keylen);
        kfree_sensitive(buffer);
        return ret;
}

int crypto_lskcipher_setkey(struct crypto_lskcipher *tfm, const u8 *key,
                            unsigned int keylen)
{
        unsigned long alignmask = crypto_lskcipher_alignmask(tfm);
        struct lskcipher_alg *cipher = crypto_lskcipher_alg(tfm);

        if (keylen < cipher->co.min_keysize || keylen > cipher->co.max_keysize)
                return -EINVAL;

        if ((unsigned long)key & alignmask)
                return lskcipher_setkey_unaligned(tfm, key, keylen);
        else
                return cipher->setkey(tfm, key, keylen);
}
EXPORT_SYMBOL_GPL(crypto_lskcipher_setkey);

static int crypto_lskcipher_crypt_unaligned(
        struct crypto_lskcipher *tfm, const u8 *src, u8 *dst, unsigned len,
        u8 *iv, int (*crypt)(struct crypto_lskcipher *tfm, const u8 *src,
                             u8 *dst, unsigned len, u8 *iv, u32 flags))
{
        unsigned statesize = crypto_lskcipher_statesize(tfm);
        unsigned ivsize = crypto_lskcipher_ivsize(tfm);
        unsigned bs = crypto_lskcipher_blocksize(tfm);
        unsigned cs = crypto_lskcipher_chunksize(tfm);
        int err;
        u8 *tiv;
        u8 *p;

        BUILD_BUG_ON(MAX_CIPHER_BLOCKSIZE > PAGE_SIZE ||
                     MAX_CIPHER_ALIGNMASK >= PAGE_SIZE);

        tiv = kmalloc(PAGE_SIZE, GFP_ATOMIC);
        if (!tiv)
                return -ENOMEM;

        memcpy(tiv, iv, ivsize + statesize);

        p = kmalloc(PAGE_SIZE, GFP_ATOMIC);
        err = -ENOMEM;
        if (!p)
                goto out;

        while (len >= bs) {
                unsigned chunk = min((unsigned)PAGE_SIZE, len);
                int err;

                if (chunk > cs)
                        chunk &= ~(cs - 1);

                memcpy(p, src, chunk);
                err = crypt(tfm, p, p, chunk, tiv, CRYPTO_LSKCIPHER_FLAG_FINAL);
                if (err)
                        goto out;

                memcpy(dst, p, chunk);
                src += chunk;
                dst += chunk;
                len -= chunk;
        }

        err = len ? -EINVAL : 0;

out:
        memcpy(iv, tiv, ivsize + statesize);
        kfree_sensitive(p);
        kfree_sensitive(tiv);
        return err;
}

static int crypto_lskcipher_crypt(struct crypto_lskcipher *tfm, const u8 *src,
                                  u8 *dst, unsigned len, u8 *iv,
                                  int (*crypt)(struct crypto_lskcipher *tfm,
                                               const u8 *src, u8 *dst,
                                               unsigned len, u8 *iv,
                                               u32 flags))
{
        unsigned long alignmask = crypto_lskcipher_alignmask(tfm);

        if (((unsigned long)src | (unsigned long)dst | (unsigned long)iv) &
            alignmask)
                return crypto_lskcipher_crypt_unaligned(tfm, src, dst, len, iv,
                                                        crypt);

        return crypt(tfm, src, dst, len, iv, CRYPTO_LSKCIPHER_FLAG_FINAL);
}

int crypto_lskcipher_encrypt(struct crypto_lskcipher *tfm, const u8 *src,
                             u8 *dst, unsigned len, u8 *iv)
{
        struct lskcipher_alg *alg = crypto_lskcipher_alg(tfm);

        return crypto_lskcipher_crypt(tfm, src, dst, len, iv, alg->encrypt);
}
EXPORT_SYMBOL_GPL(crypto_lskcipher_encrypt);

int crypto_lskcipher_decrypt(struct crypto_lskcipher *tfm, const u8 *src,
                             u8 *dst, unsigned len, u8 *iv)
{
        struct lskcipher_alg *alg = crypto_lskcipher_alg(tfm);

        return crypto_lskcipher_crypt(tfm, src, dst, len, iv, alg->decrypt);
}
EXPORT_SYMBOL_GPL(crypto_lskcipher_decrypt);

static int crypto_lskcipher_crypt_sg(struct skcipher_request *req,
                                     int (*crypt)(struct crypto_lskcipher *tfm,
                                                  const u8 *src, u8 *dst,
                                                  unsigned len, u8 *ivs,
                                                  u32 flags))
{
        struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
        struct crypto_lskcipher **ctx = crypto_skcipher_ctx(skcipher);
        u8 *ivs = skcipher_request_ctx(req);
        struct crypto_lskcipher *tfm = *ctx;
        struct skcipher_walk walk;
        unsigned ivsize;
        u32 flags;
        int err;

        ivsize = crypto_lskcipher_ivsize(tfm);
        ivs = PTR_ALIGN(ivs, crypto_skcipher_alignmask(skcipher) + 1);
        memcpy(ivs, req->iv, ivsize);

        flags = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP;

        if (req->base.flags & CRYPTO_SKCIPHER_REQ_CONT)
                flags |= CRYPTO_LSKCIPHER_FLAG_CONT;

        if (!(req->base.flags & CRYPTO_SKCIPHER_REQ_NOTFINAL))
                flags |= CRYPTO_LSKCIPHER_FLAG_FINAL;

        err = skcipher_walk_virt(&walk, req, false);

        while (walk.nbytes) {
                err = crypt(tfm, walk.src.virt.addr, walk.dst.virt.addr,
                            walk.nbytes, ivs,
                            flags & ~(walk.nbytes == walk.total ?
                            0 : CRYPTO_LSKCIPHER_FLAG_FINAL));
                err = skcipher_walk_done(&walk, err);
                flags |= CRYPTO_LSKCIPHER_FLAG_CONT;
        }

        memcpy(req->iv, ivs, ivsize);

        return err;
}

int crypto_lskcipher_encrypt_sg(struct skcipher_request *req)
{
        struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
        struct crypto_lskcipher **ctx = crypto_skcipher_ctx(skcipher);
        struct lskcipher_alg *alg = crypto_lskcipher_alg(*ctx);

        return crypto_lskcipher_crypt_sg(req, alg->encrypt);
}

int crypto_lskcipher_decrypt_sg(struct skcipher_request *req)
{
        struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
        struct crypto_lskcipher **ctx = crypto_skcipher_ctx(skcipher);
        struct lskcipher_alg *alg = crypto_lskcipher_alg(*ctx);

        return crypto_lskcipher_crypt_sg(req, alg->decrypt);
}

static void crypto_lskcipher_exit_tfm(struct crypto_tfm *tfm)
{
        struct crypto_lskcipher *skcipher = __crypto_lskcipher_cast(tfm);
        struct lskcipher_alg *alg = crypto_lskcipher_alg(skcipher);

        alg->exit(skcipher);
}

static int crypto_lskcipher_init_tfm(struct crypto_tfm *tfm)
{
        struct crypto_lskcipher *skcipher = __crypto_lskcipher_cast(tfm);
        struct lskcipher_alg *alg = crypto_lskcipher_alg(skcipher);

        if (alg->exit)
                skcipher->base.exit = crypto_lskcipher_exit_tfm;

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

        return 0;
}

static void crypto_lskcipher_free_instance(struct crypto_instance *inst)
{
        struct lskcipher_instance *skcipher =
                container_of(inst, struct lskcipher_instance, s.base);

        skcipher->free(skcipher);
}

static void __maybe_unused crypto_lskcipher_show(
        struct seq_file *m, struct crypto_alg *alg)
{
        struct lskcipher_alg *skcipher = __crypto_lskcipher_alg(alg);

        seq_printf(m, "type         : lskcipher\n");
        seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
        seq_printf(m, "min keysize  : %u\n", skcipher->co.min_keysize);
        seq_printf(m, "max keysize  : %u\n", skcipher->co.max_keysize);
        seq_printf(m, "ivsize       : %u\n", skcipher->co.ivsize);
        seq_printf(m, "chunksize    : %u\n", skcipher->co.chunksize);
        seq_printf(m, "statesize    : %u\n", skcipher->co.statesize);
}

static int __maybe_unused crypto_lskcipher_report(
        struct sk_buff *skb, struct crypto_alg *alg)
{
        struct lskcipher_alg *skcipher = __crypto_lskcipher_alg(alg);
        struct crypto_report_blkcipher rblkcipher;

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

        strscpy(rblkcipher.type, "lskcipher", sizeof(rblkcipher.type));
        strscpy(rblkcipher.geniv, "<none>", sizeof(rblkcipher.geniv));

        rblkcipher.blocksize = alg->cra_blocksize;
        rblkcipher.min_keysize = skcipher->co.min_keysize;
        rblkcipher.max_keysize = skcipher->co.max_keysize;
        rblkcipher.ivsize = skcipher->co.ivsize;

        return nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
                       sizeof(rblkcipher), &rblkcipher);
}

static const struct crypto_type crypto_lskcipher_type = {
        .extsize = crypto_alg_extsize,
        .init_tfm = crypto_lskcipher_init_tfm,
        .free = crypto_lskcipher_free_instance,
#ifdef CONFIG_PROC_FS
        .show = crypto_lskcipher_show,
#endif
#if IS_ENABLED(CONFIG_CRYPTO_USER)
        .report = crypto_lskcipher_report,
#endif
        .maskclear = ~CRYPTO_ALG_TYPE_MASK,
        .maskset = CRYPTO_ALG_TYPE_MASK,
        .type = CRYPTO_ALG_TYPE_LSKCIPHER,
        .tfmsize = offsetof(struct crypto_lskcipher, base),
        .algsize = offsetof(struct lskcipher_alg, co.base),
};

static void crypto_lskcipher_exit_tfm_sg(struct crypto_tfm *tfm)
{
        struct crypto_lskcipher **ctx = crypto_tfm_ctx(tfm);

        crypto_free_lskcipher(*ctx);
}

int crypto_init_lskcipher_ops_sg(struct crypto_tfm *tfm)
{
        struct crypto_lskcipher **ctx = crypto_tfm_ctx(tfm);
        struct crypto_alg *calg = tfm->__crt_alg;
        struct crypto_lskcipher *skcipher;

        if (!crypto_mod_get(calg))
                return -EAGAIN;

        skcipher = crypto_create_tfm(calg, &crypto_lskcipher_type);
        if (IS_ERR(skcipher)) {
                crypto_mod_put(calg);
                return PTR_ERR(skcipher);
        }

        *ctx = skcipher;
        tfm->exit = crypto_lskcipher_exit_tfm_sg;

        return 0;
}

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

struct crypto_lskcipher *crypto_alloc_lskcipher(const char *alg_name,
                                                u32 type, u32 mask)
{
        return crypto_alloc_tfm(alg_name, &crypto_lskcipher_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_lskcipher);

static int lskcipher_prepare_alg(struct lskcipher_alg *alg)
{
        struct crypto_alg *base = &alg->co.base;
        int err;

        err = skcipher_prepare_alg_common(&alg->co);
        if (err)
                return err;

        if (alg->co.chunksize & (alg->co.chunksize - 1))
                return -EINVAL;

        base->cra_type = &crypto_lskcipher_type;
        base->cra_flags |= CRYPTO_ALG_TYPE_LSKCIPHER;

        return 0;
}

int crypto_register_lskcipher(struct lskcipher_alg *alg)
{
        struct crypto_alg *base = &alg->co.base;
        int err;

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

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

void crypto_unregister_lskcipher(struct lskcipher_alg *alg)
{
        crypto_unregister_alg(&alg->co.base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_lskcipher);

int crypto_register_lskciphers(struct lskcipher_alg *algs, int count)
{
        int i, ret;

        for (i = 0; i < count; i++) {
                ret = crypto_register_lskcipher(&algs[i]);
                if (ret) {
                        crypto_unregister_lskciphers(algs, i);
                        return ret;
                }
        }

        return 0;
}
EXPORT_SYMBOL_GPL(crypto_register_lskciphers);

void crypto_unregister_lskciphers(struct lskcipher_alg *algs, int count)
{
        int i;

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

int lskcipher_register_instance(struct crypto_template *tmpl,
                                struct lskcipher_instance *inst)
{
        int err;

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

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

        return crypto_register_instance(tmpl, lskcipher_crypto_instance(inst));
}
EXPORT_SYMBOL_GPL(lskcipher_register_instance);

static int lskcipher_setkey_simple(struct crypto_lskcipher *tfm, const u8 *key,
                                   unsigned int keylen)
{
        struct crypto_lskcipher *cipher = lskcipher_cipher_simple(tfm);

        crypto_lskcipher_clear_flags(cipher, CRYPTO_TFM_REQ_MASK);
        crypto_lskcipher_set_flags(cipher, crypto_lskcipher_get_flags(tfm) &
                                   CRYPTO_TFM_REQ_MASK);
        return crypto_lskcipher_setkey(cipher, key, keylen);
}

static int lskcipher_init_tfm_simple(struct crypto_lskcipher *tfm)
{
        struct lskcipher_instance *inst = lskcipher_alg_instance(tfm);
        struct crypto_lskcipher **ctx = crypto_lskcipher_ctx(tfm);
        struct crypto_lskcipher_spawn *spawn;
        struct crypto_lskcipher *cipher;

        spawn = lskcipher_instance_ctx(inst);
        cipher = crypto_spawn_lskcipher(spawn);
        if (IS_ERR(cipher))
                return PTR_ERR(cipher);

        *ctx = cipher;
        return 0;
}

static void lskcipher_exit_tfm_simple(struct crypto_lskcipher *tfm)
{
        struct crypto_lskcipher **ctx = crypto_lskcipher_ctx(tfm);

        crypto_free_lskcipher(*ctx);
}

static void lskcipher_free_instance_simple(struct lskcipher_instance *inst)
{
        crypto_drop_lskcipher(lskcipher_instance_ctx(inst));
        kfree(inst);
}

/**
 * lskcipher_alloc_instance_simple - allocate instance of simple block cipher
 *
 * Allocate an lskcipher_instance for a simple block cipher mode of operation,
 * e.g. cbc or ecb.  The instance context will have just a single crypto_spawn,
 * that for the underlying cipher.  The {min,max}_keysize, ivsize, blocksize,
 * alignmask, and priority are set from the underlying cipher but can be
 * overridden if needed.  The tfm context defaults to
 * struct crypto_lskcipher *, and default ->setkey(), ->init(), and
 * ->exit() methods are installed.
 *
 * @tmpl: the template being instantiated
 * @tb: the template parameters
 *
 * Return: a pointer to the new instance, or an ERR_PTR().  The caller still
 *         needs to register the instance.
 */
struct lskcipher_instance *lskcipher_alloc_instance_simple(
        struct crypto_template *tmpl, struct rtattr **tb)
{
        u32 mask;
        struct lskcipher_instance *inst;
        struct crypto_lskcipher_spawn *spawn;
        char ecb_name[CRYPTO_MAX_ALG_NAME];
        struct lskcipher_alg *cipher_alg;
        const char *cipher_name;
        int err;

        err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_LSKCIPHER, &mask);
        if (err)
                return ERR_PTR(err);

        cipher_name = crypto_attr_alg_name(tb[1]);
        if (IS_ERR(cipher_name))
                return ERR_CAST(cipher_name);

        inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
        if (!inst)
                return ERR_PTR(-ENOMEM);

        spawn = lskcipher_instance_ctx(inst);
        err = crypto_grab_lskcipher(spawn,
                                    lskcipher_crypto_instance(inst),
                                    cipher_name, 0, mask);

        ecb_name[0] = 0;
        if (err == -ENOENT && !!memcmp(tmpl->name, "ecb", 4)) {
                err = -ENAMETOOLONG;
                if (snprintf(ecb_name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
                             cipher_name) >= CRYPTO_MAX_ALG_NAME)
                        goto err_free_inst;

                err = crypto_grab_lskcipher(spawn,
                                            lskcipher_crypto_instance(inst),
                                            ecb_name, 0, mask);
        }

        if (err)
                goto err_free_inst;

        cipher_alg = crypto_lskcipher_spawn_alg(spawn);

        err = crypto_inst_setname(lskcipher_crypto_instance(inst), tmpl->name,
                                  &cipher_alg->co.base);
        if (err)
                goto err_free_inst;

        if (ecb_name[0]) {
                int len;

                err = -EINVAL;
                len = strscpy(ecb_name, &cipher_alg->co.base.cra_name[4],
                              sizeof(ecb_name));
                if (len < 2)
                        goto err_free_inst;

                if (ecb_name[len - 1] != ')')
                        goto err_free_inst;

                ecb_name[len - 1] = 0;

                err = -ENAMETOOLONG;
                if (snprintf(inst->alg.co.base.cra_name, CRYPTO_MAX_ALG_NAME,
                             "%s(%s)", tmpl->name, ecb_name) >=
                    CRYPTO_MAX_ALG_NAME)
                        goto err_free_inst;

                if (strcmp(ecb_name, cipher_name) &&
                    snprintf(inst->alg.co.base.cra_driver_name,
                             CRYPTO_MAX_ALG_NAME,
                             "%s(%s)", tmpl->name, cipher_name) >=
                    CRYPTO_MAX_ALG_NAME)
                        goto err_free_inst;
        } else {
                /* Don't allow nesting. */
                err = -ELOOP;
                if ((cipher_alg->co.base.cra_flags & CRYPTO_ALG_INSTANCE))
                        goto err_free_inst;
        }

        err = -EINVAL;
        if (cipher_alg->co.ivsize)
                goto err_free_inst;

        inst->free = lskcipher_free_instance_simple;

        /* Default algorithm properties, can be overridden */
        inst->alg.co.base.cra_blocksize = cipher_alg->co.base.cra_blocksize;
        inst->alg.co.base.cra_alignmask = cipher_alg->co.base.cra_alignmask;
        inst->alg.co.base.cra_priority = cipher_alg->co.base.cra_priority;
        inst->alg.co.min_keysize = cipher_alg->co.min_keysize;
        inst->alg.co.max_keysize = cipher_alg->co.max_keysize;
        inst->alg.co.ivsize = cipher_alg->co.base.cra_blocksize;
        inst->alg.co.statesize = cipher_alg->co.statesize;

        /* Use struct crypto_lskcipher * by default, can be overridden */
        inst->alg.co.base.cra_ctxsize = sizeof(struct crypto_lskcipher *);
        inst->alg.setkey = lskcipher_setkey_simple;
        inst->alg.init = lskcipher_init_tfm_simple;
        inst->alg.exit = lskcipher_exit_tfm_simple;

        return inst;

err_free_inst:
        lskcipher_free_instance_simple(inst);
        return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(lskcipher_alloc_instance_simple);