/*

  zip_source_pkware_encode.c -- Traditional PKWARE encryption routines

  Copyright (C) 2009-2024 Dieter Baron and Thomas Klausner

  This file is part of libzip, a library to manipulate ZIP archives.

  The authors can be contacted at <info@libzip.org>

  Redistribution and use in source and binary forms, with or without

  modification, are permitted provided that the following conditions

  are met:

  1. Redistributions of source code must retain the above copyright

     notice, this list of conditions and the following disclaimer.

  2. Redistributions in binary form must reproduce the above copyright

     notice, this list of conditions and the following disclaimer in

     the documentation and/or other materials provided with the

     distribution.

  3. The names of the authors may not be used to endorse or promote

     products derived from this software without specific prior

     written permission.

  THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS

  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY

  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE

  GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER

  IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR

  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN

  IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*/

#include <stdlib.h>

#include <string.h>

#include "zipint.h"

struct trad_pkware {

    char *password;

    zip_pkware_keys_t keys;

    zip_buffer_t *buffer;

    bool eof;

    zip_dostime_t dostime;

    zip_error_t error;

};

static int encrypt_header(zip_source_t *, struct trad_pkware *);

static zip_int64_t pkware_encrypt(zip_source_t *, void *, void *, zip_uint64_t, zip_source_cmd_t);

static void trad_pkware_free(struct trad_pkware *);

static struct trad_pkware *trad_pkware_new(const char *password, zip_error_t *error);

zip_source_t *

zip_source_pkware_encode(zip_t *za, zip_source_t *src, zip_uint16_t em, int flags, const char *password) {

    struct trad_pkware *ctx;

    zip_source_t *s2;

    if (password == NULL || src == NULL || em != ZIP_EM_TRAD_PKWARE) {

        zip_error_set(&za->error, ZIP_ER_INVAL, 0);

        return NULL;

    }

    if (!(flags & ZIP_CODEC_ENCODE)) {

        zip_error_set(&za->error, ZIP_ER_ENCRNOTSUPP, 0);

        return NULL;

    }

    if ((ctx = trad_pkware_new(password, &za->error)) == NULL) {

        zip_error_set(&za->error, ZIP_ER_MEMORY, 0);

        return NULL;

    }

    if (zip_source_get_dos_time(src, &ctx->dostime) <= 0) {

        zip_stat_t st;

        if (zip_source_stat(src, &st) < 0) {

            zip_error_set_from_source(&za->error, src);

            trad_pkware_free(ctx);

            return NULL;

        }

        if (_zip_u2d_time((st.valid & ZIP_STAT_MTIME) ? st.mtime : time(NULL), &ctx->dostime, &za->error) < 0) {

            trad_pkware_free(ctx);

            return NULL;

        }

    }

    if ((s2 = zip_source_layered(za, src, pkware_encrypt, ctx)) == NULL) {

        trad_pkware_free(ctx);

        return NULL;

    }

    return s2;

}

static int

encrypt_header(zip_source_t *src, struct trad_pkware *ctx) {

    zip_uint8_t *header;

    if ((ctx->buffer = _zip_buffer_new(NULL, ZIP_CRYPTO_PKWARE_HEADERLEN)) == NULL) {

        zip_error_set(&ctx->error, ZIP_ER_MEMORY, 0);

        return -1;

    }

    header = _zip_buffer_data(ctx->buffer);

    /* generate header from random bytes and mtime

       see appnote.iz, XIII. Decryption, Step 2, last paragraph */

    if (!zip_secure_random(header, ZIP_CRYPTO_PKWARE_HEADERLEN - 1)) {

        zip_error_set(&ctx->error, ZIP_ER_INTERNAL, 0);

        _zip_buffer_free(ctx->buffer);

        ctx->buffer = NULL;

        return -1;

    }

    header[ZIP_CRYPTO_PKWARE_HEADERLEN - 1] = (zip_uint8_t)((ctx->dostime.time >> 8) & 0xff);

    _zip_pkware_encrypt(&ctx->keys, header, header, ZIP_CRYPTO_PKWARE_HEADERLEN);

    return 0;

}

static zip_int64_t

pkware_encrypt(zip_source_t *src, void *ud, void *data, zip_uint64_t length, zip_source_cmd_t cmd) {

    struct trad_pkware *ctx;

    zip_int64_t n;

    zip_uint64_t buffer_n;

    ctx = (struct trad_pkware *)ud;

    switch (cmd) {

    case ZIP_SOURCE_OPEN:

        ctx->eof = false;

        /* initialize keys */

        _zip_pkware_keys_reset(&ctx->keys);

        _zip_pkware_encrypt(&ctx->keys, NULL, (const zip_uint8_t *)ctx->password, strlen(ctx->password));

        if (encrypt_header(src, ctx) < 0) {

            return -1;

        }

        return 0;

    case ZIP_SOURCE_READ:

        buffer_n = 0;

        if (ctx->buffer) {

            /* write header values to data */

            buffer_n = _zip_buffer_read(ctx->buffer, data, length);

            data = (zip_uint8_t *)data + buffer_n;

            length -= buffer_n;

            if (_zip_buffer_eof(ctx->buffer)) {

                _zip_buffer_free(ctx->buffer);

                ctx->buffer = NULL;

            }

        }

        if (ctx->eof) {

            return (zip_int64_t)buffer_n;

        }

        if ((n = zip_source_read(src, data, length)) < 0) {

            zip_error_set_from_source(&ctx->error, src);

            return -1;

        }

        _zip_pkware_encrypt(&ctx->keys, (zip_uint8_t *)data, (zip_uint8_t *)data, (zip_uint64_t)n);

        if ((zip_uint64_t)n < length) {

            ctx->eof = true;

        }

        return (zip_int64_t)buffer_n + n;

    case ZIP_SOURCE_CLOSE:

        _zip_buffer_free(ctx->buffer);

        ctx->buffer = NULL;

        return 0;

    case ZIP_SOURCE_STAT: {

        zip_stat_t *st;

        st = (zip_stat_t *)data;

        st->encryption_method = ZIP_EM_TRAD_PKWARE;

        st->valid |= ZIP_STAT_ENCRYPTION_METHOD;

        if (st->valid & ZIP_STAT_COMP_SIZE) {

            st->comp_size += ZIP_CRYPTO_PKWARE_HEADERLEN;

        }

        return 0;

    }

    case ZIP_SOURCE_GET_FILE_ATTRIBUTES: {

        zip_file_attributes_t *attributes = (zip_file_attributes_t *)data;

        if (length < sizeof(*attributes)) {

            zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);

            return -1;

        }

        attributes->valid |= ZIP_FILE_ATTRIBUTES_VERSION_NEEDED | ZIP_FILE_ATTRIBUTES_GENERAL_PURPOSE_BIT_FLAGS;

        attributes->version_needed = 20;

        attributes->general_purpose_bit_flags = ZIP_GPBF_DATA_DESCRIPTOR;

        attributes->general_purpose_bit_mask = ZIP_GPBF_DATA_DESCRIPTOR;

        return 0;

    }

    case ZIP_SOURCE_GET_DOS_TIME:

        if (length < sizeof(ctx->dostime)) {

            zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);

            return -1;

        }

        (void)memcpy_s(data, sizeof(ctx->dostime), &ctx->dostime, sizeof(ctx->dostime));

        return sizeof(ctx->dostime);

    case ZIP_SOURCE_SUPPORTS:

        return zip_source_make_command_bitmap(ZIP_SOURCE_OPEN, ZIP_SOURCE_READ, ZIP_SOURCE_CLOSE, ZIP_SOURCE_STAT, ZIP_SOURCE_ERROR, ZIP_SOURCE_FREE, ZIP_SOURCE_GET_FILE_ATTRIBUTES, ZIP_SOURCE_GET_DOS_TIME, -1);

    case ZIP_SOURCE_ERROR:

        return zip_error_to_data(&ctx->error, data, length);

    case ZIP_SOURCE_FREE:

        trad_pkware_free(ctx);

        return 0;

    default:

        return zip_source_pass_to_lower_layer(src, data, length, cmd);

    }

}

static struct trad_pkware *

trad_pkware_new(const char *password, zip_error_t *error) {

    struct trad_pkware *ctx;

    if ((ctx = (struct trad_pkware *)malloc(sizeof(*ctx))) == NULL) {

        zip_error_set(error, ZIP_ER_MEMORY, 0);

        return NULL;

    }

    if ((ctx->password = strdup(password)) == NULL) {

        zip_error_set(error, ZIP_ER_MEMORY, 0);

        free(ctx);

        return NULL;

    }

    ctx->buffer = NULL;

    zip_error_init(&ctx->error);

    return ctx;

}

static void

trad_pkware_free(struct trad_pkware *ctx) {

    if (ctx == NULL) {

        return;

    }

    free(ctx->password);

    _zip_buffer_free(ctx->buffer);

    zip_error_fini(&ctx->error);

    free(ctx);

}