/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Common values for SHA-3 algorithms
 *
 * See also Documentation/crypto/sha3.rst
 */
#ifndef __CRYPTO_SHA3_H__
#define __CRYPTO_SHA3_H__

#include <linux/types.h>
#include <linux/string.h>

#define SHA3_224_DIGEST_SIZE    (224 / 8)
#define SHA3_224_BLOCK_SIZE     (200 - 2 * SHA3_224_DIGEST_SIZE)
#define SHA3_224_EXPORT_SIZE    SHA3_STATE_SIZE + SHA3_224_BLOCK_SIZE + 1

#define SHA3_256_DIGEST_SIZE    (256 / 8)
#define SHA3_256_BLOCK_SIZE     (200 - 2 * SHA3_256_DIGEST_SIZE)
#define SHA3_256_EXPORT_SIZE    SHA3_STATE_SIZE + SHA3_256_BLOCK_SIZE + 1

#define SHA3_384_DIGEST_SIZE    (384 / 8)
#define SHA3_384_BLOCK_SIZE     (200 - 2 * SHA3_384_DIGEST_SIZE)
#define SHA3_384_EXPORT_SIZE    SHA3_STATE_SIZE + SHA3_384_BLOCK_SIZE + 1

#define SHA3_512_DIGEST_SIZE    (512 / 8)
#define SHA3_512_BLOCK_SIZE     (200 - 2 * SHA3_512_DIGEST_SIZE)
#define SHA3_512_EXPORT_SIZE    SHA3_STATE_SIZE + SHA3_512_BLOCK_SIZE + 1

/*
 * SHAKE128 and SHAKE256 actually have variable output size, but this is used to
 * calculate the block size (rate) analogously to the above.
 */
#define SHAKE128_DEFAULT_SIZE   (128 / 8)
#define SHAKE128_BLOCK_SIZE     (200 - 2 * SHAKE128_DEFAULT_SIZE)
#define SHAKE256_DEFAULT_SIZE   (256 / 8)
#define SHAKE256_BLOCK_SIZE     (200 - 2 * SHAKE256_DEFAULT_SIZE)

#define SHA3_STATE_SIZE         200

/*
 * State for the Keccak-f[1600] permutation: 25 64-bit words.
 *
 * We usually keep the state words as little-endian, to make absorbing and
 * squeezing easier.  (It means that absorbing and squeezing can just treat the
 * state as a byte array.)  The state words are converted to native-endian only
 * temporarily by implementations of the permutation that need native-endian
 * words.  Of course, that conversion is a no-op on little-endian machines.
 */
struct sha3_state {
        union {
                __le64 words[SHA3_STATE_SIZE / 8];
                u8 bytes[SHA3_STATE_SIZE];

                u64 native_words[SHA3_STATE_SIZE / 8]; /* see comment above */
        };
};

/* Internal context, shared by the digests (SHA3-*) and the XOFs (SHAKE*) */
struct __sha3_ctx {
        struct sha3_state state;
        u8 digest_size;         /* Digests only: the digest size in bytes */
        u8 block_size;          /* Block size in bytes */
        u8 absorb_offset;       /* Index of next state byte to absorb into */
        u8 squeeze_offset;      /* XOFs only: index of next state byte to extract */
};

void __sha3_update(struct __sha3_ctx *ctx, const u8 *in, size_t in_len);

/**
 * struct sha3_ctx - Context for SHA3-224, SHA3-256, SHA3-384, or SHA3-512
 * @ctx: private
 */
struct sha3_ctx {
        struct __sha3_ctx ctx;
};

/**
 * sha3_zeroize_ctx() - Zeroize a SHA-3 context
 * @ctx: The context to zeroize
 *
 * This is already called by sha3_final().  Call this explicitly when abandoning
 * a context without calling sha3_final().
 */
static inline void sha3_zeroize_ctx(struct sha3_ctx *ctx)
{
        memzero_explicit(ctx, sizeof(*ctx));
}

/**
 * struct shake_ctx - Context for SHAKE128 or SHAKE256
 * @ctx: private
 */
struct shake_ctx {
        struct __sha3_ctx ctx;
};

/**
 * shake_zeroize_ctx() - Zeroize a SHAKE context
 * @ctx: The context to zeroize
 *
 * Call this after the last squeeze.
 */
static inline void shake_zeroize_ctx(struct shake_ctx *ctx)
{
        memzero_explicit(ctx, sizeof(*ctx));
}

/**
 * sha3_224_init() - Initialize a context for SHA3-224
 * @ctx: The context to initialize
 *
 * This begins a new SHA3-224 message digest computation.
 *
 * Context: Any context.
 */
static inline void sha3_224_init(struct sha3_ctx *ctx)
{
        *ctx = (struct sha3_ctx){
                .ctx.digest_size = SHA3_224_DIGEST_SIZE,
                .ctx.block_size = SHA3_224_BLOCK_SIZE,
        };
}

/**
 * sha3_256_init() - Initialize a context for SHA3-256
 * @ctx: The context to initialize
 *
 * This begins a new SHA3-256 message digest computation.
 *
 * Context: Any context.
 */
static inline void sha3_256_init(struct sha3_ctx *ctx)
{
        *ctx = (struct sha3_ctx){
                .ctx.digest_size = SHA3_256_DIGEST_SIZE,
                .ctx.block_size = SHA3_256_BLOCK_SIZE,
        };
}

/**
 * sha3_384_init() - Initialize a context for SHA3-384
 * @ctx: The context to initialize
 *
 * This begins a new SHA3-384 message digest computation.
 *
 * Context: Any context.
 */
static inline void sha3_384_init(struct sha3_ctx *ctx)
{
        *ctx = (struct sha3_ctx){
                .ctx.digest_size = SHA3_384_DIGEST_SIZE,
                .ctx.block_size = SHA3_384_BLOCK_SIZE,
        };
}

/**
 * sha3_512_init() - Initialize a context for SHA3-512
 * @ctx: The context to initialize
 *
 * This begins a new SHA3-512 message digest computation.
 *
 * Context: Any context.
 */
static inline void sha3_512_init(struct sha3_ctx *ctx)
{
        *ctx = (struct sha3_ctx){
                .ctx.digest_size = SHA3_512_DIGEST_SIZE,
                .ctx.block_size = SHA3_512_BLOCK_SIZE,
        };
}

/**
 * sha3_update() - Update a SHA-3 digest context with input data
 * @ctx: The context to update; must have been initialized
 * @in: The input data
 * @in_len: Length of the input data in bytes
 *
 * This can be called any number of times to add data to a SHA3-224, SHA3-256,
 * SHA3-384, or SHA3-512 digest (depending on which init function was called).
 *
 * Context: Any context.
 */
static inline void sha3_update(struct sha3_ctx *ctx,
                               const u8 *in, size_t in_len)
{
        __sha3_update(&ctx->ctx, in, in_len);
}

/**
 * sha3_final() - Finish computing a SHA-3 message digest
 * @ctx: The context to finalize; must have been initialized
 * @out: (output) The resulting SHA3-224, SHA3-256, SHA3-384, or SHA3-512
 *       message digest, matching the init function that was called.  Note that
 *       the size differs for each one; see SHA3_*_DIGEST_SIZE.
 *
 * After finishing, this zeroizes @ctx.  So the caller does not need to do it.
 *
 * Context: Any context.
 */
void sha3_final(struct sha3_ctx *ctx, u8 *out);

/**
 * shake128_init() - Initialize a context for SHAKE128
 * @ctx: The context to initialize
 *
 * This begins a new SHAKE128 extendable-output function (XOF) computation.
 *
 * Context: Any context.
 */
static inline void shake128_init(struct shake_ctx *ctx)
{
        *ctx = (struct shake_ctx){
                .ctx.block_size = SHAKE128_BLOCK_SIZE,
        };
}

/**
 * shake256_init() - Initialize a context for SHAKE256
 * @ctx: The context to initialize
 *
 * This begins a new SHAKE256 extendable-output function (XOF) computation.
 *
 * Context: Any context.
 */
static inline void shake256_init(struct shake_ctx *ctx)
{
        *ctx = (struct shake_ctx){
                .ctx.block_size = SHAKE256_BLOCK_SIZE,
        };
}

/**
 * shake_update() - Update a SHAKE context with input data
 * @ctx: The context to update; must have been initialized
 * @in: The input data
 * @in_len: Length of the input data in bytes
 *
 * This can be called any number of times to add more input data to SHAKE128 or
 * SHAKE256.  This cannot be called after squeezing has begun.
 *
 * Context: Any context.
 */
static inline void shake_update(struct shake_ctx *ctx,
                                const u8 *in, size_t in_len)
{
        __sha3_update(&ctx->ctx, in, in_len);
}

/**
 * shake_squeeze() - Generate output from SHAKE128 or SHAKE256
 * @ctx: The context to squeeze; must have been initialized
 * @out: Where to write the resulting output data
 * @out_len: The amount of data to extract to @out in bytes
 *
 * This may be called multiple times.  A number of consecutive squeezes laid
 * end-to-end will yield the same output as one big squeeze generating the same
 * total amount of output.  More input cannot be provided after squeezing has
 * begun.  After the last squeeze, call shake_zeroize_ctx().
 *
 * Context: Any context.
 */
void shake_squeeze(struct shake_ctx *ctx, u8 *out, size_t out_len);

/**
 * sha3_224() - Compute SHA3-224 digest in one shot
 * @in: The input data to be digested
 * @in_len: Length of the input data in bytes
 * @out: The buffer into which the digest will be stored
 *
 * Convenience function that computes a SHA3-224 digest.  Use this instead of
 * the incremental API if you're able to provide all the input at once.
 *
 * Context: Any context.
 */
void sha3_224(const u8 *in, size_t in_len, u8 out[SHA3_224_DIGEST_SIZE]);

/**
 * sha3_256() - Compute SHA3-256 digest in one shot
 * @in: The input data to be digested
 * @in_len: Length of the input data in bytes
 * @out: The buffer into which the digest will be stored
 *
 * Convenience function that computes a SHA3-256 digest.  Use this instead of
 * the incremental API if you're able to provide all the input at once.
 *
 * Context: Any context.
 */
void sha3_256(const u8 *in, size_t in_len, u8 out[SHA3_256_DIGEST_SIZE]);

/**
 * sha3_384() - Compute SHA3-384 digest in one shot
 * @in: The input data to be digested
 * @in_len: Length of the input data in bytes
 * @out: The buffer into which the digest will be stored
 *
 * Convenience function that computes a SHA3-384 digest.  Use this instead of
 * the incremental API if you're able to provide all the input at once.
 *
 * Context: Any context.
 */
void sha3_384(const u8 *in, size_t in_len, u8 out[SHA3_384_DIGEST_SIZE]);

/**
 * sha3_512() - Compute SHA3-512 digest in one shot
 * @in: The input data to be digested
 * @in_len: Length of the input data in bytes
 * @out: The buffer into which the digest will be stored
 *
 * Convenience function that computes a SHA3-512 digest.  Use this instead of
 * the incremental API if you're able to provide all the input at once.
 *
 * Context: Any context.
 */
void sha3_512(const u8 *in, size_t in_len, u8 out[SHA3_512_DIGEST_SIZE]);

/**
 * shake128() - Compute SHAKE128 in one shot
 * @in: The input data to be used
 * @in_len: Length of the input data in bytes
 * @out: The buffer into which the output will be stored
 * @out_len: Length of the output to produce in bytes
 *
 * Convenience function that computes SHAKE128 in one shot.  Use this instead of
 * the incremental API if you're able to provide all the input at once as well
 * as receive all the output at once.  All output lengths are supported.
 *
 * Context: Any context.
 */
void shake128(const u8 *in, size_t in_len, u8 *out, size_t out_len);

/**
 * shake256() - Compute SHAKE256 in one shot
 * @in: The input data to be used
 * @in_len: Length of the input data in bytes
 * @out: The buffer into which the output will be stored
 * @out_len: Length of the output to produce in bytes
 *
 * Convenience function that computes SHAKE256 in one shot.  Use this instead of
 * the incremental API if you're able to provide all the input at once as well
 * as receive all the output at once.  All output lengths are supported.
 *
 * Context: Any context.
 */
void shake256(const u8 *in, size_t in_len, u8 *out, size_t out_len);

#endif /* __CRYPTO_SHA3_H__ */