// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * SHA-224, SHA-256, HMAC-SHA224, and HMAC-SHA256 library functions
 *
 * Copyright (c) Jean-Luc Cooke <jlcooke@certainkey.com>
 * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 * Copyright (c) 2014 Red Hat Inc.
 * Copyright 2025 Google LLC
 */

#include <crypto/hmac.h>
#include <crypto/sha2.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/unaligned.h>
#include <linux/wordpart.h>
#include "fips.h"

static const struct sha256_block_state sha224_iv = {
        .h = {
                SHA224_H0, SHA224_H1, SHA224_H2, SHA224_H3,
                SHA224_H4, SHA224_H5, SHA224_H6, SHA224_H7,
        },
};

static const struct sha256_ctx initial_sha256_ctx = {
        .ctx = {
                .state = {
                        .h = {
                                SHA256_H0, SHA256_H1, SHA256_H2, SHA256_H3,
                                SHA256_H4, SHA256_H5, SHA256_H6, SHA256_H7,
                        },
                },
                .bytecount = 0,
        },
};

#define sha256_iv (initial_sha256_ctx.ctx.state)

static const u32 sha256_K[64] = {
        0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
        0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
        0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
        0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
        0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
        0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
        0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
        0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
        0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
        0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
        0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
};

#define Ch(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
#define Maj(x, y, z) (((x) & (y)) | ((z) & ((x) | (y))))
#define e0(x) (ror32((x), 2) ^ ror32((x), 13) ^ ror32((x), 22))
#define e1(x) (ror32((x), 6) ^ ror32((x), 11) ^ ror32((x), 25))
#define s0(x) (ror32((x), 7) ^ ror32((x), 18) ^ ((x) >> 3))
#define s1(x) (ror32((x), 17) ^ ror32((x), 19) ^ ((x) >> 10))

static inline void LOAD_OP(int I, u32 *W, const u8 *input)
{
        W[I] = get_unaligned_be32((__u32 *)input + I);
}

static inline void BLEND_OP(int I, u32 *W)
{
        W[I] = s1(W[I - 2]) + W[I - 7] + s0(W[I - 15]) + W[I - 16];
}

#define SHA256_ROUND(i, a, b, c, d, e, f, g, h)                    \
        do {                                                       \
                u32 t1, t2;                                        \
                t1 = h + e1(e) + Ch(e, f, g) + sha256_K[i] + W[i]; \
                t2 = e0(a) + Maj(a, b, c);                         \
                d += t1;                                           \
                h = t1 + t2;                                       \
        } while (0)

static void sha256_block_generic(struct sha256_block_state *state,
                                 const u8 *input, u32 W[64])
{
        u32 a, b, c, d, e, f, g, h;
        int i;

        /* load the input */
        for (i = 0; i < 16; i += 8) {
                LOAD_OP(i + 0, W, input);
                LOAD_OP(i + 1, W, input);
                LOAD_OP(i + 2, W, input);
                LOAD_OP(i + 3, W, input);
                LOAD_OP(i + 4, W, input);
                LOAD_OP(i + 5, W, input);
                LOAD_OP(i + 6, W, input);
                LOAD_OP(i + 7, W, input);
        }

        /* now blend */
        for (i = 16; i < 64; i += 8) {
                BLEND_OP(i + 0, W);
                BLEND_OP(i + 1, W);
                BLEND_OP(i + 2, W);
                BLEND_OP(i + 3, W);
                BLEND_OP(i + 4, W);
                BLEND_OP(i + 5, W);
                BLEND_OP(i + 6, W);
                BLEND_OP(i + 7, W);
        }

        /* load the state into our registers */
        a = state->h[0];
        b = state->h[1];
        c = state->h[2];
        d = state->h[3];
        e = state->h[4];
        f = state->h[5];
        g = state->h[6];
        h = state->h[7];

        /* now iterate */
        for (i = 0; i < 64; i += 8) {
                SHA256_ROUND(i + 0, a, b, c, d, e, f, g, h);
                SHA256_ROUND(i + 1, h, a, b, c, d, e, f, g);
                SHA256_ROUND(i + 2, g, h, a, b, c, d, e, f);
                SHA256_ROUND(i + 3, f, g, h, a, b, c, d, e);
                SHA256_ROUND(i + 4, e, f, g, h, a, b, c, d);
                SHA256_ROUND(i + 5, d, e, f, g, h, a, b, c);
                SHA256_ROUND(i + 6, c, d, e, f, g, h, a, b);
                SHA256_ROUND(i + 7, b, c, d, e, f, g, h, a);
        }

        state->h[0] += a;
        state->h[1] += b;
        state->h[2] += c;
        state->h[3] += d;
        state->h[4] += e;
        state->h[5] += f;
        state->h[6] += g;
        state->h[7] += h;
}

static void __maybe_unused
sha256_blocks_generic(struct sha256_block_state *state,
                      const u8 *data, size_t nblocks)
{
        u32 W[64];

        do {
                sha256_block_generic(state, data, W);
                data += SHA256_BLOCK_SIZE;
        } while (--nblocks);

        memzero_explicit(W, sizeof(W));
}

#if defined(CONFIG_CRYPTO_LIB_SHA256_ARCH) && !defined(__DISABLE_EXPORTS)
#include "sha256.h" /* $(SRCARCH)/sha256.h */
#else
#define sha256_blocks sha256_blocks_generic
#endif

static void __sha256_init(struct __sha256_ctx *ctx,
                          const struct sha256_block_state *iv,
                          u64 initial_bytecount)
{
        ctx->state = *iv;
        ctx->bytecount = initial_bytecount;
}

void sha224_init(struct sha224_ctx *ctx)
{
        __sha256_init(&ctx->ctx, &sha224_iv, 0);
}
EXPORT_SYMBOL_GPL(sha224_init);

void sha256_init(struct sha256_ctx *ctx)
{
        __sha256_init(&ctx->ctx, &sha256_iv, 0);
}
EXPORT_SYMBOL_GPL(sha256_init);

void __sha256_update(struct __sha256_ctx *ctx, const u8 *data, size_t len)
{
        size_t partial = ctx->bytecount % SHA256_BLOCK_SIZE;

        ctx->bytecount += len;

        if (partial + len >= SHA256_BLOCK_SIZE) {
                size_t nblocks;

                if (partial) {
                        size_t l = SHA256_BLOCK_SIZE - partial;

                        memcpy(&ctx->buf[partial], data, l);
                        data += l;
                        len -= l;

                        sha256_blocks(&ctx->state, ctx->buf, 1);
                }

                nblocks = len / SHA256_BLOCK_SIZE;
                len %= SHA256_BLOCK_SIZE;

                if (nblocks) {
                        sha256_blocks(&ctx->state, data, nblocks);
                        data += nblocks * SHA256_BLOCK_SIZE;
                }
                partial = 0;
        }
        if (len)
                memcpy(&ctx->buf[partial], data, len);
}
EXPORT_SYMBOL(__sha256_update);

static void __sha256_final(struct __sha256_ctx *ctx,
                           u8 *out, size_t digest_size)
{
        u64 bitcount = ctx->bytecount << 3;
        size_t partial = ctx->bytecount % SHA256_BLOCK_SIZE;

        ctx->buf[partial++] = 0x80;
        if (partial > SHA256_BLOCK_SIZE - 8) {
                memset(&ctx->buf[partial], 0, SHA256_BLOCK_SIZE - partial);
                sha256_blocks(&ctx->state, ctx->buf, 1);
                partial = 0;
        }
        memset(&ctx->buf[partial], 0, SHA256_BLOCK_SIZE - 8 - partial);
        *(__be64 *)&ctx->buf[SHA256_BLOCK_SIZE - 8] = cpu_to_be64(bitcount);
        sha256_blocks(&ctx->state, ctx->buf, 1);

        for (size_t i = 0; i < digest_size; i += 4)
                put_unaligned_be32(ctx->state.h[i / 4], out + i);
}

void sha224_final(struct sha224_ctx *ctx, u8 out[SHA224_DIGEST_SIZE])
{
        __sha256_final(&ctx->ctx, out, SHA224_DIGEST_SIZE);
        memzero_explicit(ctx, sizeof(*ctx));
}
EXPORT_SYMBOL(sha224_final);

void sha256_final(struct sha256_ctx *ctx, u8 out[SHA256_DIGEST_SIZE])
{
        __sha256_final(&ctx->ctx, out, SHA256_DIGEST_SIZE);
        memzero_explicit(ctx, sizeof(*ctx));
}
EXPORT_SYMBOL(sha256_final);

void sha224(const u8 *data, size_t len, u8 out[SHA224_DIGEST_SIZE])
{
        struct sha224_ctx ctx;

        sha224_init(&ctx);
        sha224_update(&ctx, data, len);
        sha224_final(&ctx, out);
}
EXPORT_SYMBOL(sha224);

void sha256(const u8 *data, size_t len, u8 out[SHA256_DIGEST_SIZE])
{
        struct sha256_ctx ctx;

        sha256_init(&ctx);
        sha256_update(&ctx, data, len);
        sha256_final(&ctx, out);
}
EXPORT_SYMBOL(sha256);

/*
 * Pre-boot environments (as indicated by __DISABLE_EXPORTS being defined) just
 * need the generic SHA-256 code.  Omit all other features from them.
 */
#ifndef __DISABLE_EXPORTS

#ifndef sha256_finup_2x_arch
static bool sha256_finup_2x_arch(const struct __sha256_ctx *ctx,
                                 const u8 *data1, const u8 *data2, size_t len,
                                 u8 out1[SHA256_DIGEST_SIZE],
                                 u8 out2[SHA256_DIGEST_SIZE])
{
        return false;
}
static bool sha256_finup_2x_is_optimized_arch(void)
{
        return false;
}
#endif

/* Sequential fallback implementation of sha256_finup_2x() */
static noinline_for_stack void sha256_finup_2x_sequential(
        const struct __sha256_ctx *ctx, const u8 *data1, const u8 *data2,
        size_t len, u8 out1[SHA256_DIGEST_SIZE], u8 out2[SHA256_DIGEST_SIZE])
{
        struct __sha256_ctx mut_ctx;

        mut_ctx = *ctx;
        __sha256_update(&mut_ctx, data1, len);
        __sha256_final(&mut_ctx, out1, SHA256_DIGEST_SIZE);

        mut_ctx = *ctx;
        __sha256_update(&mut_ctx, data2, len);
        __sha256_final(&mut_ctx, out2, SHA256_DIGEST_SIZE);
}

void sha256_finup_2x(const struct sha256_ctx *ctx, const u8 *data1,
                     const u8 *data2, size_t len, u8 out1[SHA256_DIGEST_SIZE],
                     u8 out2[SHA256_DIGEST_SIZE])
{
        if (ctx == NULL)
                ctx = &initial_sha256_ctx;

        if (likely(sha256_finup_2x_arch(&ctx->ctx, data1, data2, len, out1,
                                        out2)))
                return;
        sha256_finup_2x_sequential(&ctx->ctx, data1, data2, len, out1, out2);
}
EXPORT_SYMBOL_GPL(sha256_finup_2x);

bool sha256_finup_2x_is_optimized(void)
{
        return sha256_finup_2x_is_optimized_arch();
}
EXPORT_SYMBOL_GPL(sha256_finup_2x_is_optimized);

static void __hmac_sha256_preparekey(struct sha256_block_state *istate,
                                     struct sha256_block_state *ostate,
                                     const u8 *raw_key, size_t raw_key_len,
                                     const struct sha256_block_state *iv)
{
        union {
                u8 b[SHA256_BLOCK_SIZE];
                unsigned long w[SHA256_BLOCK_SIZE / sizeof(unsigned long)];
        } derived_key = { 0 };

        if (unlikely(raw_key_len > SHA256_BLOCK_SIZE)) {
                if (iv == &sha224_iv)
                        sha224(raw_key, raw_key_len, derived_key.b);
                else
                        sha256(raw_key, raw_key_len, derived_key.b);
        } else {
                memcpy(derived_key.b, raw_key, raw_key_len);
        }

        for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++)
                derived_key.w[i] ^= REPEAT_BYTE(HMAC_IPAD_VALUE);
        *istate = *iv;
        sha256_blocks(istate, derived_key.b, 1);

        for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++)
                derived_key.w[i] ^= REPEAT_BYTE(HMAC_OPAD_VALUE ^
                                                HMAC_IPAD_VALUE);
        *ostate = *iv;
        sha256_blocks(ostate, derived_key.b, 1);

        memzero_explicit(&derived_key, sizeof(derived_key));
}

void hmac_sha224_preparekey(struct hmac_sha224_key *key,
                            const u8 *raw_key, size_t raw_key_len)
{
        __hmac_sha256_preparekey(&key->key.istate, &key->key.ostate,
                                 raw_key, raw_key_len, &sha224_iv);
}
EXPORT_SYMBOL_GPL(hmac_sha224_preparekey);

void hmac_sha256_preparekey(struct hmac_sha256_key *key,
                            const u8 *raw_key, size_t raw_key_len)
{
        __hmac_sha256_preparekey(&key->key.istate, &key->key.ostate,
                                 raw_key, raw_key_len, &sha256_iv);
}
EXPORT_SYMBOL_GPL(hmac_sha256_preparekey);

void __hmac_sha256_init(struct __hmac_sha256_ctx *ctx,
                        const struct __hmac_sha256_key *key)
{
        __sha256_init(&ctx->sha_ctx, &key->istate, SHA256_BLOCK_SIZE);
        ctx->ostate = key->ostate;
}
EXPORT_SYMBOL_GPL(__hmac_sha256_init);

void hmac_sha224_init_usingrawkey(struct hmac_sha224_ctx *ctx,
                                  const u8 *raw_key, size_t raw_key_len)
{
        __hmac_sha256_preparekey(&ctx->ctx.sha_ctx.state, &ctx->ctx.ostate,
                                 raw_key, raw_key_len, &sha224_iv);
        ctx->ctx.sha_ctx.bytecount = SHA256_BLOCK_SIZE;
}
EXPORT_SYMBOL_GPL(hmac_sha224_init_usingrawkey);

void hmac_sha256_init_usingrawkey(struct hmac_sha256_ctx *ctx,
                                  const u8 *raw_key, size_t raw_key_len)
{
        __hmac_sha256_preparekey(&ctx->ctx.sha_ctx.state, &ctx->ctx.ostate,
                                 raw_key, raw_key_len, &sha256_iv);
        ctx->ctx.sha_ctx.bytecount = SHA256_BLOCK_SIZE;
}
EXPORT_SYMBOL_GPL(hmac_sha256_init_usingrawkey);

static void __hmac_sha256_final(struct __hmac_sha256_ctx *ctx,
                                u8 *out, size_t digest_size)
{
        /* Generate the padded input for the outer hash in ctx->sha_ctx.buf. */
        __sha256_final(&ctx->sha_ctx, ctx->sha_ctx.buf, digest_size);
        memset(&ctx->sha_ctx.buf[digest_size], 0,
               SHA256_BLOCK_SIZE - digest_size);
        ctx->sha_ctx.buf[digest_size] = 0x80;
        *(__be32 *)&ctx->sha_ctx.buf[SHA256_BLOCK_SIZE - 4] =
                cpu_to_be32(8 * (SHA256_BLOCK_SIZE + digest_size));

        /* Compute the outer hash, which gives the HMAC value. */
        sha256_blocks(&ctx->ostate, ctx->sha_ctx.buf, 1);
        for (size_t i = 0; i < digest_size; i += 4)
                put_unaligned_be32(ctx->ostate.h[i / 4], out + i);

        memzero_explicit(ctx, sizeof(*ctx));
}

void hmac_sha224_final(struct hmac_sha224_ctx *ctx,
                       u8 out[SHA224_DIGEST_SIZE])
{
        __hmac_sha256_final(&ctx->ctx, out, SHA224_DIGEST_SIZE);
}
EXPORT_SYMBOL_GPL(hmac_sha224_final);

void hmac_sha256_final(struct hmac_sha256_ctx *ctx,
                       u8 out[SHA256_DIGEST_SIZE])
{
        __hmac_sha256_final(&ctx->ctx, out, SHA256_DIGEST_SIZE);
}
EXPORT_SYMBOL_GPL(hmac_sha256_final);

void hmac_sha224(const struct hmac_sha224_key *key,
                 const u8 *data, size_t data_len, u8 out[SHA224_DIGEST_SIZE])
{
        struct hmac_sha224_ctx ctx;

        hmac_sha224_init(&ctx, key);
        hmac_sha224_update(&ctx, data, data_len);
        hmac_sha224_final(&ctx, out);
}
EXPORT_SYMBOL_GPL(hmac_sha224);

void hmac_sha256(const struct hmac_sha256_key *key,
                 const u8 *data, size_t data_len, u8 out[SHA256_DIGEST_SIZE])
{
        struct hmac_sha256_ctx ctx;

        hmac_sha256_init(&ctx, key);
        hmac_sha256_update(&ctx, data, data_len);
        hmac_sha256_final(&ctx, out);
}
EXPORT_SYMBOL_GPL(hmac_sha256);

void hmac_sha224_usingrawkey(const u8 *raw_key, size_t raw_key_len,
                             const u8 *data, size_t data_len,
                             u8 out[SHA224_DIGEST_SIZE])
{
        struct hmac_sha224_ctx ctx;

        hmac_sha224_init_usingrawkey(&ctx, raw_key, raw_key_len);
        hmac_sha224_update(&ctx, data, data_len);
        hmac_sha224_final(&ctx, out);
}
EXPORT_SYMBOL_GPL(hmac_sha224_usingrawkey);

void hmac_sha256_usingrawkey(const u8 *raw_key, size_t raw_key_len,
                             const u8 *data, size_t data_len,
                             u8 out[SHA256_DIGEST_SIZE])
{
        struct hmac_sha256_ctx ctx;

        hmac_sha256_init_usingrawkey(&ctx, raw_key, raw_key_len);
        hmac_sha256_update(&ctx, data, data_len);
        hmac_sha256_final(&ctx, out);
}
EXPORT_SYMBOL_GPL(hmac_sha256_usingrawkey);

#if defined(sha256_mod_init_arch) || defined(CONFIG_CRYPTO_FIPS)
static int __init sha256_mod_init(void)
{
#ifdef sha256_mod_init_arch
        sha256_mod_init_arch();
#endif
        if (fips_enabled) {
                /*
                 * FIPS cryptographic algorithm self-test.  As per the FIPS
                 * Implementation Guidance, testing HMAC-SHA256 satisfies the
                 * test requirement for SHA-224, SHA-256, and HMAC-SHA224 too.
                 */
                u8 mac[SHA256_DIGEST_SIZE];

                hmac_sha256_usingrawkey(fips_test_key, sizeof(fips_test_key),
                                        fips_test_data, sizeof(fips_test_data),
                                        mac);
                if (memcmp(fips_test_hmac_sha256_value, mac, sizeof(mac)) != 0)
                        panic("sha256: FIPS self-test failed\n");
        }
        return 0;
}
subsys_initcall(sha256_mod_init);

static void __exit sha256_mod_exit(void)
{
}
module_exit(sha256_mod_exit);
#endif

#endif /* !__DISABLE_EXPORTS */

MODULE_DESCRIPTION("SHA-224, SHA-256, HMAC-SHA224, and HMAC-SHA256 library functions");
MODULE_LICENSE("GPL");