// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * SHA-3, as specified in
 * https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.202.pdf
 *
 * SHA-3 code by Jeff Garzik <jeff@garzik.org>
 *               Ard Biesheuvel <ard.biesheuvel@linaro.org>
 *               David Howells <dhowells@redhat.com>
 *
 * See also Documentation/crypto/sha3.rst
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <crypto/sha3.h>
#include <crypto/utils.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/unaligned.h>
#include "fips.h"

/*
 * On some 32-bit architectures, such as h8300, GCC ends up using over 1 KB of
 * stack if the round calculation gets inlined into the loop in
 * sha3_keccakf_generic().  On the other hand, on 64-bit architectures with
 * plenty of [64-bit wide] general purpose registers, not inlining it severely
 * hurts performance.  So let's use 64-bitness as a heuristic to decide whether
 * to inline or not.
 */
#ifdef CONFIG_64BIT
#define SHA3_INLINE inline
#else
#define SHA3_INLINE noinline
#endif

#define SHA3_KECCAK_ROUNDS 24

static const u64 sha3_keccakf_rndc[SHA3_KECCAK_ROUNDS] = {
        0x0000000000000001ULL, 0x0000000000008082ULL, 0x800000000000808aULL,
        0x8000000080008000ULL, 0x000000000000808bULL, 0x0000000080000001ULL,
        0x8000000080008081ULL, 0x8000000000008009ULL, 0x000000000000008aULL,
        0x0000000000000088ULL, 0x0000000080008009ULL, 0x000000008000000aULL,
        0x000000008000808bULL, 0x800000000000008bULL, 0x8000000000008089ULL,
        0x8000000000008003ULL, 0x8000000000008002ULL, 0x8000000000000080ULL,
        0x000000000000800aULL, 0x800000008000000aULL, 0x8000000080008081ULL,
        0x8000000000008080ULL, 0x0000000080000001ULL, 0x8000000080008008ULL
};

/*
 * Perform a single round of Keccak mixing.
 */
static SHA3_INLINE void sha3_keccakf_one_round_generic(u64 st[25], int round)
{
        u64 t[5], tt, bc[5];

        /* Theta */
        bc[0] = st[0] ^ st[5] ^ st[10] ^ st[15] ^ st[20];
        bc[1] = st[1] ^ st[6] ^ st[11] ^ st[16] ^ st[21];
        bc[2] = st[2] ^ st[7] ^ st[12] ^ st[17] ^ st[22];
        bc[3] = st[3] ^ st[8] ^ st[13] ^ st[18] ^ st[23];
        bc[4] = st[4] ^ st[9] ^ st[14] ^ st[19] ^ st[24];

        t[0] = bc[4] ^ rol64(bc[1], 1);
        t[1] = bc[0] ^ rol64(bc[2], 1);
        t[2] = bc[1] ^ rol64(bc[3], 1);
        t[3] = bc[2] ^ rol64(bc[4], 1);
        t[4] = bc[3] ^ rol64(bc[0], 1);

        st[0] ^= t[0];

        /* Rho Pi */
        tt = st[1];
        st[ 1] = rol64(st[ 6] ^ t[1], 44);
        st[ 6] = rol64(st[ 9] ^ t[4], 20);
        st[ 9] = rol64(st[22] ^ t[2], 61);
        st[22] = rol64(st[14] ^ t[4], 39);
        st[14] = rol64(st[20] ^ t[0], 18);
        st[20] = rol64(st[ 2] ^ t[2], 62);
        st[ 2] = rol64(st[12] ^ t[2], 43);
        st[12] = rol64(st[13] ^ t[3], 25);
        st[13] = rol64(st[19] ^ t[4],  8);
        st[19] = rol64(st[23] ^ t[3], 56);
        st[23] = rol64(st[15] ^ t[0], 41);
        st[15] = rol64(st[ 4] ^ t[4], 27);
        st[ 4] = rol64(st[24] ^ t[4], 14);
        st[24] = rol64(st[21] ^ t[1],  2);
        st[21] = rol64(st[ 8] ^ t[3], 55);
        st[ 8] = rol64(st[16] ^ t[1], 45);
        st[16] = rol64(st[ 5] ^ t[0], 36);
        st[ 5] = rol64(st[ 3] ^ t[3], 28);
        st[ 3] = rol64(st[18] ^ t[3], 21);
        st[18] = rol64(st[17] ^ t[2], 15);
        st[17] = rol64(st[11] ^ t[1], 10);
        st[11] = rol64(st[ 7] ^ t[2],  6);
        st[ 7] = rol64(st[10] ^ t[0],  3);
        st[10] = rol64(    tt ^ t[1],  1);

        /* Chi */
        bc[ 0] = ~st[ 1] & st[ 2];
        bc[ 1] = ~st[ 2] & st[ 3];
        bc[ 2] = ~st[ 3] & st[ 4];
        bc[ 3] = ~st[ 4] & st[ 0];
        bc[ 4] = ~st[ 0] & st[ 1];
        st[ 0] ^= bc[ 0];
        st[ 1] ^= bc[ 1];
        st[ 2] ^= bc[ 2];
        st[ 3] ^= bc[ 3];
        st[ 4] ^= bc[ 4];

        bc[ 0] = ~st[ 6] & st[ 7];
        bc[ 1] = ~st[ 7] & st[ 8];
        bc[ 2] = ~st[ 8] & st[ 9];
        bc[ 3] = ~st[ 9] & st[ 5];
        bc[ 4] = ~st[ 5] & st[ 6];
        st[ 5] ^= bc[ 0];
        st[ 6] ^= bc[ 1];
        st[ 7] ^= bc[ 2];
        st[ 8] ^= bc[ 3];
        st[ 9] ^= bc[ 4];

        bc[ 0] = ~st[11] & st[12];
        bc[ 1] = ~st[12] & st[13];
        bc[ 2] = ~st[13] & st[14];
        bc[ 3] = ~st[14] & st[10];
        bc[ 4] = ~st[10] & st[11];
        st[10] ^= bc[ 0];
        st[11] ^= bc[ 1];
        st[12] ^= bc[ 2];
        st[13] ^= bc[ 3];
        st[14] ^= bc[ 4];

        bc[ 0] = ~st[16] & st[17];
        bc[ 1] = ~st[17] & st[18];
        bc[ 2] = ~st[18] & st[19];
        bc[ 3] = ~st[19] & st[15];
        bc[ 4] = ~st[15] & st[16];
        st[15] ^= bc[ 0];
        st[16] ^= bc[ 1];
        st[17] ^= bc[ 2];
        st[18] ^= bc[ 3];
        st[19] ^= bc[ 4];

        bc[ 0] = ~st[21] & st[22];
        bc[ 1] = ~st[22] & st[23];
        bc[ 2] = ~st[23] & st[24];
        bc[ 3] = ~st[24] & st[20];
        bc[ 4] = ~st[20] & st[21];
        st[20] ^= bc[ 0];
        st[21] ^= bc[ 1];
        st[22] ^= bc[ 2];
        st[23] ^= bc[ 3];
        st[24] ^= bc[ 4];

        /* Iota */
        st[0] ^= sha3_keccakf_rndc[round];
}

/* Generic implementation of the Keccak-f[1600] permutation */
static void sha3_keccakf_generic(struct sha3_state *state)
{
        /*
         * Temporarily convert the state words from little-endian to native-
         * endian so that they can be operated on.  Note that on little-endian
         * machines this conversion is a no-op and is optimized out.
         */

        for (int i = 0; i < ARRAY_SIZE(state->words); i++)
                state->native_words[i] = le64_to_cpu(state->words[i]);

        for (int round = 0; round < SHA3_KECCAK_ROUNDS; round++)
                sha3_keccakf_one_round_generic(state->native_words, round);

        for (int i = 0; i < ARRAY_SIZE(state->words); i++)
                state->words[i] = cpu_to_le64(state->native_words[i]);
}

/*
 * Generic implementation of absorbing the given nonzero number of full blocks
 * into the sponge function Keccak[r=8*block_size, c=1600-8*block_size].
 */
static void __maybe_unused
sha3_absorb_blocks_generic(struct sha3_state *state, const u8 *data,
                           size_t nblocks, size_t block_size)
{
        do {
                for (size_t i = 0; i < block_size; i += 8)
                        state->words[i / 8] ^= get_unaligned((__le64 *)&data[i]);
                sha3_keccakf_generic(state);
                data += block_size;
        } while (--nblocks);
}

#ifdef CONFIG_CRYPTO_LIB_SHA3_ARCH
#include "sha3.h" /* $(SRCARCH)/sha3.h */
#else
#define sha3_keccakf            sha3_keccakf_generic
#define sha3_absorb_blocks      sha3_absorb_blocks_generic
#endif

void __sha3_update(struct __sha3_ctx *ctx, const u8 *in, size_t in_len)
{
        const size_t block_size = ctx->block_size;
        size_t absorb_offset = ctx->absorb_offset;

        /* Warn if squeezing has already begun. */
        WARN_ON_ONCE(absorb_offset >= block_size);

        if (absorb_offset && absorb_offset + in_len >= block_size) {
                crypto_xor(&ctx->state.bytes[absorb_offset], in,
                           block_size - absorb_offset);
                in += block_size - absorb_offset;
                in_len -= block_size - absorb_offset;
                sha3_keccakf(&ctx->state);
                absorb_offset = 0;
        }

        if (in_len >= block_size) {
                size_t nblocks = in_len / block_size;

                sha3_absorb_blocks(&ctx->state, in, nblocks, block_size);
                in += nblocks * block_size;
                in_len -= nblocks * block_size;
        }

        if (in_len) {
                crypto_xor(&ctx->state.bytes[absorb_offset], in, in_len);
                absorb_offset += in_len;
        }
        ctx->absorb_offset = absorb_offset;
}
EXPORT_SYMBOL_GPL(__sha3_update);

void sha3_final(struct sha3_ctx *sha3_ctx, u8 *out)
{
        struct __sha3_ctx *ctx = &sha3_ctx->ctx;

        ctx->state.bytes[ctx->absorb_offset] ^= 0x06;
        ctx->state.bytes[ctx->block_size - 1] ^= 0x80;
        sha3_keccakf(&ctx->state);
        memcpy(out, ctx->state.bytes, ctx->digest_size);
        sha3_zeroize_ctx(sha3_ctx);
}
EXPORT_SYMBOL_GPL(sha3_final);

void shake_squeeze(struct shake_ctx *shake_ctx, u8 *out, size_t out_len)
{
        struct __sha3_ctx *ctx = &shake_ctx->ctx;
        const size_t block_size = ctx->block_size;
        size_t squeeze_offset = ctx->squeeze_offset;

        if (ctx->absorb_offset < block_size) {
                /* First squeeze: */

                /* Add the domain separation suffix and padding. */
                ctx->state.bytes[ctx->absorb_offset] ^= 0x1f;
                ctx->state.bytes[block_size - 1] ^= 0x80;

                /* Indicate that squeezing has begun. */
                ctx->absorb_offset = block_size;

                /*
                 * Indicate that no output is pending yet, i.e. sha3_keccakf()
                 * will need to be called before the first copy.
                 */
                squeeze_offset = block_size;
        }
        while (out_len) {
                if (squeeze_offset == block_size) {
                        sha3_keccakf(&ctx->state);
                        squeeze_offset = 0;
                }
                size_t copy = min(out_len, block_size - squeeze_offset);

                memcpy(out, &ctx->state.bytes[squeeze_offset], copy);
                out += copy;
                out_len -= copy;
                squeeze_offset += copy;
        }
        ctx->squeeze_offset = squeeze_offset;
}
EXPORT_SYMBOL_GPL(shake_squeeze);

#ifndef sha3_224_arch
static inline bool sha3_224_arch(const u8 *in, size_t in_len,
                                 u8 out[SHA3_224_DIGEST_SIZE])
{
        return false;
}
#endif
#ifndef sha3_256_arch
static inline bool sha3_256_arch(const u8 *in, size_t in_len,
                                 u8 out[SHA3_256_DIGEST_SIZE])
{
        return false;
}
#endif
#ifndef sha3_384_arch
static inline bool sha3_384_arch(const u8 *in, size_t in_len,
                                 u8 out[SHA3_384_DIGEST_SIZE])
{
        return false;
}
#endif
#ifndef sha3_512_arch
static inline bool sha3_512_arch(const u8 *in, size_t in_len,
                                 u8 out[SHA3_512_DIGEST_SIZE])
{
        return false;
}
#endif

void sha3_224(const u8 *in, size_t in_len, u8 out[SHA3_224_DIGEST_SIZE])
{
        struct sha3_ctx ctx;

        if (sha3_224_arch(in, in_len, out))
                return;
        sha3_224_init(&ctx);
        sha3_update(&ctx, in, in_len);
        sha3_final(&ctx, out);
}
EXPORT_SYMBOL_GPL(sha3_224);

void sha3_256(const u8 *in, size_t in_len, u8 out[SHA3_256_DIGEST_SIZE])
{
        struct sha3_ctx ctx;

        if (sha3_256_arch(in, in_len, out))
                return;
        sha3_256_init(&ctx);
        sha3_update(&ctx, in, in_len);
        sha3_final(&ctx, out);
}
EXPORT_SYMBOL_GPL(sha3_256);

void sha3_384(const u8 *in, size_t in_len, u8 out[SHA3_384_DIGEST_SIZE])
{
        struct sha3_ctx ctx;

        if (sha3_384_arch(in, in_len, out))
                return;
        sha3_384_init(&ctx);
        sha3_update(&ctx, in, in_len);
        sha3_final(&ctx, out);
}
EXPORT_SYMBOL_GPL(sha3_384);

void sha3_512(const u8 *in, size_t in_len, u8 out[SHA3_512_DIGEST_SIZE])
{
        struct sha3_ctx ctx;

        if (sha3_512_arch(in, in_len, out))
                return;
        sha3_512_init(&ctx);
        sha3_update(&ctx, in, in_len);
        sha3_final(&ctx, out);
}
EXPORT_SYMBOL_GPL(sha3_512);

void shake128(const u8 *in, size_t in_len, u8 *out, size_t out_len)
{
        struct shake_ctx ctx;

        shake128_init(&ctx);
        shake_update(&ctx, in, in_len);
        shake_squeeze(&ctx, out, out_len);
        shake_zeroize_ctx(&ctx);
}
EXPORT_SYMBOL_GPL(shake128);

void shake256(const u8 *in, size_t in_len, u8 *out, size_t out_len)
{
        struct shake_ctx ctx;

        shake256_init(&ctx);
        shake_update(&ctx, in, in_len);
        shake_squeeze(&ctx, out, out_len);
        shake_zeroize_ctx(&ctx);
}
EXPORT_SYMBOL_GPL(shake256);

#if defined(sha3_mod_init_arch) || defined(CONFIG_CRYPTO_FIPS)
static int __init sha3_mod_init(void)
{
#ifdef sha3_mod_init_arch
        sha3_mod_init_arch();
#endif
        if (fips_enabled) {
                /*
                 * FIPS cryptographic algorithm self-test.  As per the FIPS
                 * Implementation Guidance, testing any SHA-3 algorithm
                 * satisfies the test requirement for all of them.
                 */
                u8 hash[SHA3_256_DIGEST_SIZE];

                sha3_256(fips_test_data, sizeof(fips_test_data), hash);
                if (memcmp(fips_test_sha3_256_value, hash, sizeof(hash)) != 0)
                        panic("sha3: FIPS self-test failed\n");
        }
        return 0;
}
subsys_initcall(sha3_mod_init);

static void __exit sha3_mod_exit(void)
{
}
module_exit(sha3_mod_exit);
#endif

MODULE_DESCRIPTION("SHA-3 library functions");
MODULE_LICENSE("GPL");