/*
 * Copyright 2010-2022 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <sys/types.h>
#include <sys/endian.h>
#include <sys/systm.h>

#include <crypto/openssl/ossl.h>
#include <crypto/openssl/ossl_arm.h>
#include <crypto/openssl/ossl_aes_gcm.h>
#include <crypto/openssl/ossl_cipher.h>
#include <crypto/openssl/arm_arch.h>

#include <opencrypto/cryptodev.h>

_Static_assert(
    sizeof(struct ossl_gcm_context) <= sizeof(struct ossl_cipher_context),
    "ossl_gcm_context too large");

void AES_encrypt(const void *in, void *out, const void *ks);
void AES_set_encrypt_key(const void *key, int keylen, void *ks);

void gcm_init_neon(__uint128_t Htable[16], const uint64_t Xi[2]);
void gcm_gmult_neon(uint64_t Xi[2], const __uint128_t Htable[16]);
void gcm_ghash_neon(uint64_t Xi[2], const __uint128_t Htable[16],
    const void *in, size_t len);

void ossl_bsaes_ctr32_encrypt_blocks(const unsigned char *in,
    unsigned char *out, size_t blocks, void *ks, const unsigned char *iv);

static void
gcm_init(struct ossl_gcm_context *ctx, const void *key, size_t keylen)
{
        memset(&ctx->gcm, 0, sizeof(ctx->gcm));
        memset(&ctx->aes_ks, 0, sizeof(ctx->aes_ks));

        AES_set_encrypt_key(key, keylen, &ctx->aes_ks);
        AES_encrypt(ctx->gcm.H.c, ctx->gcm.H.c, &ctx->aes_ks);

#if BYTE_ORDER == LITTLE_ENDIAN
        ctx->gcm.H.u[0] = bswap64(ctx->gcm.H.u[0]);
        ctx->gcm.H.u[1] = bswap64(ctx->gcm.H.u[1]);
#endif

        gcm_init_neon(ctx->gcm.Htable, ctx->gcm.H.u);
}

static void
gcm_setiv(struct ossl_gcm_context *ctx, const unsigned char *iv, size_t len)
{
        uint32_t ctr;

        KASSERT(len == AES_GCM_IV_LEN,
            ("%s: invalid IV length %zu", __func__, len));

        ctx->gcm.len.u[0] = 0;
        ctx->gcm.len.u[1] = 0;
        ctx->gcm.ares = ctx->gcm.mres = 0;

        memcpy(ctx->gcm.Yi.c, iv, len);
        ctx->gcm.Yi.c[12] = 0;
        ctx->gcm.Yi.c[13] = 0;
        ctx->gcm.Yi.c[14] = 0;
        ctx->gcm.Yi.c[15] = 1;
        ctr = 1;

        ctx->gcm.Xi.u[0] = 0;
        ctx->gcm.Xi.u[1] = 0;

        AES_encrypt(ctx->gcm.Yi.c, ctx->gcm.EK0.c, &ctx->aes_ks);
        ctr++;

#if BYTE_ORDER == LITTLE_ENDIAN
        ctx->gcm.Yi.d[3] = bswap32(ctr);
#else
        ctx->gcm.Yi.d[3] = ctr;
#endif
}

static int
gcm_finish(struct ossl_gcm_context *ctx, const unsigned char *tag, size_t len)
{
        uint64_t alen = ctx->gcm.len.u[0] << 3;
        uint64_t clen = ctx->gcm.len.u[1] << 3;

        if (ctx->gcm.mres || ctx->gcm.ares)
                gcm_gmult_neon(ctx->gcm.Xi.u, ctx->gcm.Htable);

#if BYTE_ORDER == LITTLE_ENDIAN
        alen = bswap64(alen);
        clen = bswap64(clen);
#endif

        ctx->gcm.Xi.u[0] ^= alen;
        ctx->gcm.Xi.u[1] ^= clen;
        gcm_gmult_neon(ctx->gcm.Xi.u, ctx->gcm.Htable);

        ctx->gcm.Xi.u[0] ^= ctx->gcm.EK0.u[0];
        ctx->gcm.Xi.u[1] ^= ctx->gcm.EK0.u[1];

        if (tag != NULL)
                return timingsafe_bcmp(ctx->gcm.Xi.c, tag, len);
        return 0;
}

static int
gcm_aad(struct ossl_gcm_context *ctx, const unsigned char *aad, size_t len)
{
        size_t i;
        unsigned int n;
        uint64_t alen = ctx->gcm.len.u[0];

        if (ctx->gcm.len.u[1])
                return -2;

        alen += len;
        if (alen > ((uint64_t)1 << 61) || (sizeof(len) == 8 && alen < len))
                return -1;
        ctx->gcm.len.u[0] = alen;

        n = ctx->gcm.ares;
        if (n) {
                while (n && len) {
                        ctx->gcm.Xi.c[n] ^= *(aad++);
                        --len;
                        n = (n + 1) % 16;
                }
                if (n == 0)
                        gcm_gmult_neon(ctx->gcm.Xi.u, ctx->gcm.Htable);
                else {
                        ctx->gcm.ares = n;
                        return 0;
                }
        }
        if ((i = (len & (size_t)-AES_BLOCK_LEN))) {
                gcm_ghash_neon(ctx->gcm.Xi.u, ctx->gcm.Htable, aad, i);
                aad += i;
                len -= i;
        }
        if (len) {
                n = (unsigned int)len;
                for (i = 0; i < len; ++i)
                        ctx->gcm.Xi.c[i] ^= aad[i];
        }

        ctx->gcm.ares = n;
        return 0;
}

static int
gcm_encrypt(struct ossl_gcm_context *ctx, const unsigned char *in,
    unsigned char *out, size_t len)
{
        struct bsaes_key bsks;
        unsigned int n, ctr, mres;
        size_t i;
        uint64_t mlen = ctx->gcm.len.u[1];

        mlen += len;
        if (mlen > (((uint64_t)1 << 36) - 32) ||
            (sizeof(len) == 8 && mlen < len))
                return -1;
        ctx->gcm.len.u[1] = mlen;

        mres = ctx->gcm.mres;

        if (ctx->gcm.ares) {
                /* First call to encrypt finalizes GHASH(AAD) */
                gcm_gmult_neon(ctx->gcm.Xi.u, ctx->gcm.Htable);
                ctx->gcm.ares = 0;
        }

#if BYTE_ORDER == LITTLE_ENDIAN
        ctr = bswap32(ctx->gcm.Yi.d[3]);
#else
        ctr = ctx->gcm.Yi.d[3];
#endif

        n = mres % 16;
        if (n) {
                while (n && len) {
                        ctx->gcm.Xi.c[n] ^= *(out++) = *(in++) ^ ctx->gcm.EKi.c[n];
                        --len;
                        n = (n + 1) % 16;
                }
                if (n == 0) {
                        gcm_gmult_neon(ctx->gcm.Xi.u, ctx->gcm.Htable);
                        mres = 0;
                } else {
                        ctx->gcm.mres = n;
                        return 0;
                }
        }
        if ((i = (len & (size_t)-16))) {
                size_t j = i / 16;

                memcpy(&bsks.ks, &ctx->aes_ks, sizeof(bsks.ks));
                bsks.converted = 0;
                ossl_bsaes_ctr32_encrypt_blocks(in, out, j, &bsks,
                    ctx->gcm.Yi.c);
                ctr += (unsigned int)j;
#if BYTE_ORDER == LITTLE_ENDIAN
                ctx->gcm.Yi.d[3] = bswap32(ctr);
#else
                ctx->gcm.Yi.d[3] = ctr;
#endif
                in += i;
                len -= i;
                while (j--) {
                        for (i = 0; i < 16; ++i)
                                ctx->gcm.Xi.c[i] ^= out[i];
                        gcm_gmult_neon(ctx->gcm.Xi.u, ctx->gcm.Htable);
                        out += 16;
                }
        }
        if (len) {
                AES_encrypt(ctx->gcm.Yi.c, ctx->gcm.EKi.c, &ctx->aes_ks);
                ++ctr;
#if BYTE_ORDER == LITTLE_ENDIAN
                ctx->gcm.Yi.d[3] = bswap32(ctr);
#else
                ctx->gcm.Yi.d[3] = ctr;
#endif
                while (len--) {
                        ctx->gcm.Xi.c[mres++] ^= out[n] = in[n] ^ ctx->gcm.EKi.c[n];
                        ++n;
                }
        }

        ctx->gcm.mres = mres;
        return 0;
}

static int
gcm_decrypt(struct ossl_gcm_context *ctx, const unsigned char *in,
    unsigned char *out, size_t len)
{
        struct bsaes_key bsks;
        unsigned int n, ctr, mres;
        size_t i;
        uint64_t mlen = ctx->gcm.len.u[1];

        mlen += len;
        if (mlen > ((1ull << 36) - 32) || (sizeof(len) == 8 && mlen < len))
                return -1;
        ctx->gcm.len.u[1] = mlen;

        mres = ctx->gcm.mres;

        if (ctx->gcm.ares) {
                /* First call to decrypt finalizes GHASH(AAD) */
                gcm_gmult_neon(ctx->gcm.Xi.u, ctx->gcm.Htable);
                ctx->gcm.ares = 0;
        }

#if BYTE_ORDER == LITTLE_ENDIAN
        ctr = bswap32(ctx->gcm.Yi.d[3]);
#else
        ctr = ctx->gcm.Yi.d[3];
#endif

        n = mres % 16;
        if (n) {
                while (n && len) {
                        uint8_t c = *(in++);
                        *(out++) = c ^ ctx->gcm.EKi.c[n];
                        ctx->gcm.Xi.c[n] ^= c;
                        --len;
                        n = (n + 1) % 16;
                }
                if (n == 0) {
                        gcm_gmult_neon(ctx->gcm.Xi.u, ctx->gcm.Htable);
                        mres = 0;
                } else {
                        ctx->gcm.mres = n;
                        return 0;
                }
        }
        if ((i = (len & (size_t)-16))) {
                size_t j = i / 16;

                while (j--) {
                        size_t k;
                        for (k = 0; k < 16; ++k)
                                ctx->gcm.Xi.c[k] ^= in[k];
                        gcm_gmult_neon(ctx->gcm.Xi.u, ctx->gcm.Htable);
                        in += 16;
                }
                j = i / 16;
                in -= i;
                memcpy(&bsks.ks, &ctx->aes_ks, sizeof(bsks.ks));
                bsks.converted = 0;
                ossl_bsaes_ctr32_encrypt_blocks(in, out, j, &bsks,
                    ctx->gcm.Yi.c);
                ctr += (unsigned int)j;
#if BYTE_ORDER == LITTLE_ENDIAN
                ctx->gcm.Yi.d[3] = bswap32(ctr);
#else
                ctx->gcm.Yi.d[3] = ctr;
#endif
                out += i;
                in += i;
                len -= i;
        }
        if (len) {
                AES_encrypt(ctx->gcm.Yi.c, ctx->gcm.EKi.c, &ctx->aes_ks);
                ++ctr;
#if BYTE_ORDER == LITTLE_ENDIAN
                ctx->gcm.Yi.d[3] = bswap32(ctr);
#else
                ctx->gcm.Yi.d[3] = ctr;
#endif
                while (len--) {
                        uint8_t c = in[n];
                        ctx->gcm.Xi.c[mres++] ^= c;
                        out[n] = c ^ ctx->gcm.EKi.c[n];
                        ++n;
                }
        }

        ctx->gcm.mres = mres;
        return 0;
}

static void
gcm_tag(struct ossl_gcm_context *ctx, unsigned char *tag, size_t len)
{
        gcm_finish(ctx, NULL, 0);
        memcpy(tag, ctx->gcm.Xi.c, len);
}

static const struct ossl_aes_gcm_ops gcm_ops_neon = {
        .init = gcm_init,
        .setiv = gcm_setiv,
        .aad = gcm_aad,
        .encrypt = gcm_encrypt,
        .decrypt = gcm_decrypt,
        .finish = gcm_finish,
        .tag = gcm_tag,
};

int ossl_aes_gcm_setkey(const unsigned char *key, int klen, void *_ctx);

int
ossl_aes_gcm_setkey(const unsigned char *key, int klen, void *_ctx)
{
        struct ossl_gcm_context *ctx;

        ctx = _ctx;
        ctx->ops = &gcm_ops_neon;
        gcm_init(ctx, key, klen);
        return (0);
}