/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8 -*-â
âvi: set net ft=c ts=4 sts=4 sw=4 fenc=utf-8                                :viâ
ââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââ
â                                                                              â
â Argon2 reference source code package - reference C implementations           â
â                                                                              â
â Copyright 2015                                                               â
â Daniel Dinu, Dmitry Khovratovich, Jean-Philippe Aumasson, and Samuel Neves   â
â                                                                              â
â You may use this work under the terms of a Creative Commons CC0 1.0          â
â License/Waiver or the Apache Public License 2.0, at your option. The         â
â terms of these licenses can be found at:                                     â
â                                                                              â
â - CC0 1.0 Universal : https://creativecommons.org/publicdomain/zero/1.0      â
â - Apache 2.0        : https://www.apache.org/licenses/LICENSE-2.0            â
â                                                                              â
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#include "libc/limits.h"
#include "libc/mem/mem.h"
#include "libc/str/str.h"
#include "third_party/argon2/argon2.h"
#include "third_party/argon2/core.h"
#include "third_party/argon2/encoding.h"

asm(".ident\t\"\\n\\n\
argon2 (CC0 or Apache2)\\n\
Copyright 2016 Daniel Dinu, Dmitry Khovratovich\\n\
Copyright 2016 Jean-Philippe Aumasson, Samuel Neves\"");
/* clang-format off */

/**
 * Function that gives the string representation of an argon2_type.
 * @param type The argon2_type that we want the string for
 * @param uppercase Whether the string should have the first letter uppercase
 * @return NULL if invalid type, otherwise the string representation.
 */
const char *argon2_type2string(argon2_type type, int uppercase) {
    switch (type) {
        case Argon2_d:
            return uppercase ? "Argon2d" : "argon2d";
        case Argon2_i:
            return uppercase ? "Argon2i" : "argon2i";
        case Argon2_id:
            return uppercase ? "Argon2id" : "argon2id";
    }
    return NULL;
}

/**
 * Function that performs memory-hard hashing with certain degree of parallelism
 * @param  context  Pointer to the Argon2 internal structure
 * @return Error code if smth is wrong, ARGON2_OK otherwise
 */
int argon2_ctx(argon2_context *context, argon2_type type) {
    /* 1. Validate all inputs */
    int result = validate_inputs(context);
    uint32_t memory_blocks, segment_length;
    argon2_instance_t instance;

    if (ARGON2_OK != result) {
        return result;
    }

    if (Argon2_d != type && Argon2_i != type && Argon2_id != type) {
        return ARGON2_INCORRECT_TYPE;
    }

    /* 2. Align memory size */
    /* Minimum memory_blocks = 8L blocks, where L is the number of lanes */
    memory_blocks = context->m_cost;

    if (memory_blocks < 2 * ARGON2_SYNC_POINTS * context->lanes) {
        memory_blocks = 2 * ARGON2_SYNC_POINTS * context->lanes;
    }

    segment_length = memory_blocks / (context->lanes * ARGON2_SYNC_POINTS);
    /* Ensure that all segments have equal length */
    memory_blocks = segment_length * (context->lanes * ARGON2_SYNC_POINTS);

    instance.version = context->version;
    instance.memory = NULL;
    instance.passes = context->t_cost;
    instance.memory_blocks = memory_blocks;
    instance.segment_length = segment_length;
    instance.lane_length = segment_length * ARGON2_SYNC_POINTS;
    instance.lanes = context->lanes;
    instance.threads = context->threads;
    instance.type = type;

    if (instance.threads > instance.lanes) {
        instance.threads = instance.lanes;
    }

    /* 3. Initialization: Hashing inputs, allocating memory, filling first
     * blocks
     */
    result = initialize(&instance, context);

    if (ARGON2_OK != result) {
        return result;
    }

    /* 4. Filling memory */
    result = fill_memory_blocks(&instance);

    if (ARGON2_OK != result) {
        return result;
    }
    /* 5. Finalization */
    finalize(context, &instance);

    return ARGON2_OK;
}

int argon2_hash(const uint32_t t_cost, const uint32_t m_cost,
                const uint32_t parallelism, const void *pwd,
                const size_t pwdlen, const void *salt, const size_t saltlen,
                void *hash, const size_t hashlen, char *encoded,
                const size_t encodedlen, argon2_type type,
                const uint32_t version){

    argon2_context context;
    int result;
    uint8_t *out;

    if (pwdlen > ARGON2_MAX_PWD_LENGTH) {
        return ARGON2_PWD_TOO_LONG;
    }

    if (saltlen > ARGON2_MAX_SALT_LENGTH) {
        return ARGON2_SALT_TOO_LONG;
    }

    if (hashlen > ARGON2_MAX_OUTLEN) {
        return ARGON2_OUTPUT_TOO_LONG;
    }

    if (hashlen < ARGON2_MIN_OUTLEN) {
        return ARGON2_OUTPUT_TOO_SHORT;
    }

    out = malloc(hashlen);
    if (!out) {
        return ARGON2_MEMORY_ALLOCATION_ERROR;
    }

    context.out = (uint8_t *)out;
    context.outlen = (uint32_t)hashlen;
    context.pwd = (uint8_t *)(uintptr_t)pwd;
    context.pwdlen = (uint32_t)pwdlen;
    context.salt = (uint8_t *)(uintptr_t)salt;
    context.saltlen = (uint32_t)saltlen;
    context.secret = NULL;
    context.secretlen = 0;
    context.ad = NULL;
    context.adlen = 0;
    context.t_cost = t_cost;
    context.m_cost = m_cost;
    context.lanes = parallelism;
    context.threads = parallelism;
    context.allocate_cbk = NULL;
    context.free_cbk = NULL;
    context.flags = ARGON2_DEFAULT_FLAGS;
    context.version = version;

    result = argon2_ctx(&context, type);

    if (result != ARGON2_OK) {
        clear_internal_memory(out, hashlen);
        free(out);
        return result;
    }

    /* if raw hash requested, write it */
    if (hash) {
        memcpy(hash, out, hashlen);
    }

    /* if encoding requested, write it */
    if (encoded && encodedlen) {
        if (encode_string(encoded, encodedlen, &context, type) != ARGON2_OK) {
            clear_internal_memory(out, hashlen); /* wipe buffers if error */
            clear_internal_memory(encoded, encodedlen);
            free(out);
            return ARGON2_ENCODING_FAIL;
        }
    }
    clear_internal_memory(out, hashlen);
    free(out);

    return ARGON2_OK;
}

/**
 * Hashes a password with Argon2i, producing an encoded hash
 * @param t_cost Number of iterations
 * @param m_cost Sets memory usage to m_cost kibibytes
 * @param parallelism Number of threads and compute lanes
 * @param pwd Pointer to password
 * @param pwdlen Password size in bytes
 * @param salt Pointer to salt
 * @param saltlen Salt size in bytes
 * @param hashlen Desired length of the hash in bytes
 * @param encoded Buffer where to write the encoded hash
 * @param encodedlen Size of the buffer (thus max size of the encoded hash)
 * @pre   Different parallelism levels will give different results
 * @pre   Returns ARGON2_OK if successful
 */
int argon2i_hash_encoded(const uint32_t t_cost, const uint32_t m_cost,
                         const uint32_t parallelism, const void *pwd,
                         const size_t pwdlen, const void *salt,
                         const size_t saltlen, const size_t hashlen,
                         char *encoded, const size_t encodedlen) {

    return argon2_hash(t_cost, m_cost, parallelism, pwd, pwdlen, salt, saltlen,
                       NULL, hashlen, encoded, encodedlen, Argon2_i,
                       ARGON2_VERSION_NUMBER);
}

/**
 * Hashes a password with Argon2i, producing a raw hash at @hash
 * @param t_cost Number of iterations
 * @param m_cost Sets memory usage to m_cost kibibytes
 * @param parallelism Number of threads and compute lanes
 * @param pwd Pointer to password
 * @param pwdlen Password size in bytes
 * @param salt Pointer to salt
 * @param saltlen Salt size in bytes
 * @param hash Buffer where to write the raw hash - updated by the function
 * @param hashlen Desired length of the hash in bytes
 * @pre   Different parallelism levels will give different results
 * @pre   Returns ARGON2_OK if successful
 */
int argon2i_hash_raw(const uint32_t t_cost, const uint32_t m_cost,
                     const uint32_t parallelism, const void *pwd,
                     const size_t pwdlen, const void *salt,
                     const size_t saltlen, void *hash, const size_t hashlen) {

    return argon2_hash(t_cost, m_cost, parallelism, pwd, pwdlen, salt, saltlen,
                       hash, hashlen, NULL, 0, Argon2_i, ARGON2_VERSION_NUMBER);
}

int argon2d_hash_encoded(const uint32_t t_cost, const uint32_t m_cost,
                         const uint32_t parallelism, const void *pwd,
                         const size_t pwdlen, const void *salt,
                         const size_t saltlen, const size_t hashlen,
                         char *encoded, const size_t encodedlen) {

    return argon2_hash(t_cost, m_cost, parallelism, pwd, pwdlen, salt, saltlen,
                       NULL, hashlen, encoded, encodedlen, Argon2_d,
                       ARGON2_VERSION_NUMBER);
}

int argon2d_hash_raw(const uint32_t t_cost, const uint32_t m_cost,
                     const uint32_t parallelism, const void *pwd,
                     const size_t pwdlen, const void *salt,
                     const size_t saltlen, void *hash, const size_t hashlen) {

    return argon2_hash(t_cost, m_cost, parallelism, pwd, pwdlen, salt, saltlen,
                       hash, hashlen, NULL, 0, Argon2_d, ARGON2_VERSION_NUMBER);
}

int argon2id_hash_encoded(const uint32_t t_cost, const uint32_t m_cost,
                          const uint32_t parallelism, const void *pwd,
                          const size_t pwdlen, const void *salt,
                          const size_t saltlen, const size_t hashlen,
                          char *encoded, const size_t encodedlen) {

    return argon2_hash(t_cost, m_cost, parallelism, pwd, pwdlen, salt, saltlen,
                       NULL, hashlen, encoded, encodedlen, Argon2_id,
                       ARGON2_VERSION_NUMBER);
}

int argon2id_hash_raw(const uint32_t t_cost, const uint32_t m_cost,
                      const uint32_t parallelism, const void *pwd,
                      const size_t pwdlen, const void *salt,
                      const size_t saltlen, void *hash, const size_t hashlen) {
    return argon2_hash(t_cost, m_cost, parallelism, pwd, pwdlen, salt, saltlen,
                       hash, hashlen, NULL, 0, Argon2_id,
                       ARGON2_VERSION_NUMBER);
}

static int argon2_compare(const uint8_t *b1, const uint8_t *b2, size_t len) {
    size_t i;
    uint8_t d = 0U;

    for (i = 0U; i < len; i++) {
        d |= b1[i] ^ b2[i];
    }
    return (int)((1 & ((d - 1) >> 8)) - 1);
}

int argon2_verify(const char *encoded, const void *pwd, const size_t pwdlen,
                  argon2_type type) {

    argon2_context ctx;
    uint8_t *desired_result = NULL;
    int ret = ARGON2_OK;
    size_t encoded_len;
    uint32_t max_field_len;

    if (pwdlen > ARGON2_MAX_PWD_LENGTH) {
        return ARGON2_PWD_TOO_LONG;
    }

    if (encoded == NULL) {
        return ARGON2_DECODING_FAIL;
    }

    encoded_len = strlen(encoded);
    if (encoded_len > UINT32_MAX) {
        return ARGON2_DECODING_FAIL;
    }

    /* No field can be longer than the encoded length */
    max_field_len = (uint32_t)encoded_len;

    ctx.saltlen = max_field_len;
    ctx.outlen = max_field_len;

    ctx.salt = malloc(ctx.saltlen);
    ctx.out = malloc(ctx.outlen);
    if (!ctx.salt || !ctx.out) {
        ret = ARGON2_MEMORY_ALLOCATION_ERROR;
        goto fail;
    }

    ctx.pwd = (uint8_t *)pwd;
    ctx.pwdlen = (uint32_t)pwdlen;

    ret = decode_string(&ctx, encoded, type);
    if (ret != ARGON2_OK) {
        goto fail;
    }

    /* Set aside the desired result, and get a new buffer. */
    desired_result = ctx.out;
    ctx.out = malloc(ctx.outlen);
    if (!ctx.out) {
        ret = ARGON2_MEMORY_ALLOCATION_ERROR;
        goto fail;
    }

    ret = argon2_verify_ctx(&ctx, (char *)desired_result, type);
    if (ret != ARGON2_OK) {
        goto fail;
    }

fail:
    free(ctx.salt);
    free(ctx.out);
    free(desired_result);

    return ret;
}

/**
 * Verifies a password against an encoded string
 * Encoded string is restricted as in validate_inputs()
 * @param encoded String encoding parameters, salt, hash
 * @param pwd Pointer to password
 * @pre   Returns ARGON2_OK if successful
 */
int argon2i_verify(const char *encoded, const void *pwd, const size_t pwdlen) {

    return argon2_verify(encoded, pwd, pwdlen, Argon2_i);
}

int argon2d_verify(const char *encoded, const void *pwd, const size_t pwdlen) {

    return argon2_verify(encoded, pwd, pwdlen, Argon2_d);
}

int argon2id_verify(const char *encoded, const void *pwd, const size_t pwdlen) {

    return argon2_verify(encoded, pwd, pwdlen, Argon2_id);
}

/**
 * Argon2d: Version of Argon2 that picks memory blocks depending
 * on the password and salt. Only for side-channel-free
 * environment!!
 *****
 * @param  context  Pointer to current Argon2 context
 * @return  Zero if successful, a non zero error code otherwise
 */
int argon2d_ctx(argon2_context *context) {
    return argon2_ctx(context, Argon2_d);
}

/**
 * Argon2i: Version of Argon2 that picks memory blocks
 * independent on the password and salt. Good for side-channels,
 * but worse w.r.t. tradeoff attacks if only one pass is used.
 *****
 * @param  context  Pointer to current Argon2 context
 * @return  Zero if successful, a non zero error code otherwise
 */
int argon2i_ctx(argon2_context *context) {
    return argon2_ctx(context, Argon2_i);
}

/**
 * Argon2id: Version of Argon2 where the first half-pass over memory is
 * password-independent, the rest are password-dependent (on the password and
 * salt). OK against side channels (they reduce to 1/2-pass Argon2i), and
 * better with w.r.t. tradeoff attacks (similar to Argon2d).
 *****
 * @param  context  Pointer to current Argon2 context
 * @return  Zero if successful, a non zero error code otherwise
 */
int argon2id_ctx(argon2_context *context) {
    return argon2_ctx(context, Argon2_id);
}

int argon2_verify_ctx(argon2_context *context, const char *hash,
                      argon2_type type) {
    int ret = argon2_ctx(context, type);
    if (ret != ARGON2_OK) {
        return ret;
    }

    if (argon2_compare((uint8_t *)hash, context->out, context->outlen)) {
        return ARGON2_VERIFY_MISMATCH;
    }

    return ARGON2_OK;
}

/**
 * Verify if a given password is correct for Argon2d hashing
 * @param  context  Pointer to current Argon2 context
 * @param  hash  The password hash to verify. The length of the hash is
 * specified by the context outlen member
 * @return  Zero if successful, a non zero error code otherwise
 */
int argon2d_verify_ctx(argon2_context *context, const char *hash) {
    return argon2_verify_ctx(context, hash, Argon2_d);
}

/**
 * Verify if a given password is correct for Argon2i hashing
 * @param  context  Pointer to current Argon2 context
 * @param  hash  The password hash to verify. The length of the hash is
 * specified by the context outlen member
 * @return  Zero if successful, a non zero error code otherwise
 */
int argon2i_verify_ctx(argon2_context *context, const char *hash) {
    return argon2_verify_ctx(context, hash, Argon2_i);
}

/**
 * Verify if a given password is correct for Argon2id hashing
 * @param  context  Pointer to current Argon2 context
 * @param  hash  The password hash to verify. The length of the hash is
 * specified by the context outlen member
 * @return  Zero if successful, a non zero error code otherwise
 */
int argon2id_verify_ctx(argon2_context *context, const char *hash) {
    return argon2_verify_ctx(context, hash, Argon2_id);
}

/**
 * Get the associated error message for given error code
 * @return  The error message associated with the given error code
 */
const char *argon2_error_message(int error_code) {
    switch (error_code) {
    case ARGON2_OK:
        return "OK";
    case ARGON2_OUTPUT_PTR_NULL:
        return "Output pointer is NULL";
    case ARGON2_OUTPUT_TOO_SHORT:
        return "Output is too short";
    case ARGON2_OUTPUT_TOO_LONG:
        return "Output is too long";
    case ARGON2_PWD_TOO_SHORT:
        return "Password is too short";
    case ARGON2_PWD_TOO_LONG:
        return "Password is too long";
    case ARGON2_SALT_TOO_SHORT:
        return "Salt is too short";
    case ARGON2_SALT_TOO_LONG:
        return "Salt is too long";
    case ARGON2_AD_TOO_SHORT:
        return "Associated data is too short";
    case ARGON2_AD_TOO_LONG:
        return "Associated data is too long";
    case ARGON2_SECRET_TOO_SHORT:
        return "Secret is too short";
    case ARGON2_SECRET_TOO_LONG:
        return "Secret is too long";
    case ARGON2_TIME_TOO_SMALL:
        return "Time cost is too small";
    case ARGON2_TIME_TOO_LARGE:
        return "Time cost is too large";
    case ARGON2_MEMORY_TOO_LITTLE:
        return "Memory cost is too small";
    case ARGON2_MEMORY_TOO_MUCH:
        return "Memory cost is too large";
    case ARGON2_LANES_TOO_FEW:
        return "Too few lanes";
    case ARGON2_LANES_TOO_MANY:
        return "Too many lanes";
    case ARGON2_PWD_PTR_MISMATCH:
        return "Password pointer is NULL, but password length is not 0";
    case ARGON2_SALT_PTR_MISMATCH:
        return "Salt pointer is NULL, but salt length is not 0";
    case ARGON2_SECRET_PTR_MISMATCH:
        return "Secret pointer is NULL, but secret length is not 0";
    case ARGON2_AD_PTR_MISMATCH:
        return "Associated data pointer is NULL, but ad length is not 0";
    case ARGON2_MEMORY_ALLOCATION_ERROR:
        return "Memory allocation error";
    case ARGON2_FREE_MEMORY_CBK_NULL:
        return "The free memory callback is NULL";
    case ARGON2_ALLOCATE_MEMORY_CBK_NULL:
        return "The allocate memory callback is NULL";
    case ARGON2_INCORRECT_PARAMETER:
        return "Argon2_Context context is NULL";
    case ARGON2_INCORRECT_TYPE:
        return "There is no such version of Argon2";
    case ARGON2_OUT_PTR_MISMATCH:
        return "Output pointer mismatch";
    case ARGON2_THREADS_TOO_FEW:
        return "Not enough threads";
    case ARGON2_THREADS_TOO_MANY:
        return "Too many threads";
    case ARGON2_MISSING_ARGS:
        return "Missing arguments";
    case ARGON2_ENCODING_FAIL:
        return "Encoding failed";
    case ARGON2_DECODING_FAIL:
        return "Decoding failed";
    case ARGON2_THREAD_FAIL:
        return "Threading failure";
    case ARGON2_DECODING_LENGTH_FAIL:
        return "Some of encoded parameters are too long or too short";
    case ARGON2_VERIFY_MISMATCH:
        return "The password does not match the supplied hash";
    default:
        return "Unknown error code";
    }
}

/**
 * Returns the encoded hash length for the given input parameters
 * @param t_cost  Number of iterations
 * @param m_cost  Memory usage in kibibytes
 * @param parallelism  Number of threads; used to compute lanes
 * @param saltlen  Salt size in bytes
 * @param hashlen  Hash size in bytes
 * @param type The argon2_type that we want the encoded length for
 * @return  The encoded hash length in bytes
 */
size_t argon2_encodedlen(uint32_t t_cost, uint32_t m_cost, uint32_t parallelism,
                         uint32_t saltlen, uint32_t hashlen, argon2_type type) {
  return strlen("$$v=$m=,t=,p=$$") + strlen(argon2_type2string(type, 0)) +
         numlen(t_cost) + numlen(m_cost) + numlen(parallelism) +
         b64len(saltlen) + b64len(hashlen) + numlen(ARGON2_VERSION_NUMBER) + 1;
}
