lib/zip_source_winzip_aes_decode.c - third_party/libzip - Git at Google

 /*
   zip_source_winzip_aes.c -- Winzip AES de/encryption routines
   Copyright (C) 2009-2015 Dieter Baron and Thomas Klausner

   This file is part of libzip, a library to manipulate ZIP archives.
   The authors can be contacted at <libzip@nih.at>

   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"

 #include "gladman-fcrypt.h"

 #define MAX_HEADER_LENGTH (16+PWD_VER_LENGTH)
 #define HMAC_LENGTH 10

 static int salt_length[] = { 0, 8, 12, 16 };

 struct winzip_aes {
     char *password;
     int mode;

     zip_uint64_t data_length;
     zip_uint64_t current_position;

     fcrypt_ctx fcrypt_ctx;
     zip_error_t error;
 };


 static int decrypt_header(zip_source_t *src, struct winzip_aes *ctx);
 static void winzip_aes_free(struct winzip_aes *);
 static zip_int64_t winzip_aes_decrypt(zip_source_t *src, void *ud, void *data, zip_uint64_t len, zip_source_cmd_t cmd);
 static struct winzip_aes * winzip_aes_new(int mode, const char *password);


 zip_source_t *
 zip_source_winzip_aes_decode(zip_t *za, zip_source_t *src, zip_uint16_t em, int flags, const char *password)
 {
     zip_source_t *s2;
     int mode = 0;
     zip_stat_t st;
     zip_uint64_t aux_length;
     struct winzip_aes *ctx;

     switch (em) {
     case ZIP_EM_AES_128:
 	mode = 1;
 	break;
     case ZIP_EM_AES_192:
 	mode = 2;
 	break;
     case ZIP_EM_AES_256:
 	mode = 3;
 	break;
     }

     if (password == NULL || src == NULL || mode == 0) {
 	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 (zip_source_stat(src, &st) != 0) {
 	_zip_error_set_from_source(&za->error, src);
 	return NULL;
     }

     aux_length = PWD_VER_LENGTH + salt_length[mode] + HMAC_LENGTH;

     if ((st.valid & ZIP_STAT_COMP_SIZE) == 0 || st.comp_size < aux_length) {
 	zip_error_set(&za->error, ZIP_ER_OPNOTSUPP, 0);
 	return NULL;
     }

     if ((ctx = winzip_aes_new(mode, password)) == NULL) {
 	zip_error_set(&za->error, ZIP_ER_MEMORY, 0);
 	return NULL;
     }

     ctx->data_length = st.comp_size - aux_length;

     if ((s2 = zip_source_layered(za, src, winzip_aes_decrypt, ctx)) == NULL) {
 	winzip_aes_free(ctx);
 	return NULL;
     }

     return s2;
 }


 static int
 decrypt_header(zip_source_t *src, struct winzip_aes *ctx)
 {
     zip_uint8_t header[MAX_HEADER_LENGTH];
     zip_uint8_t password_verification[PWD_VER_LENGTH];
     zip_uint8_t headerlen;
     zip_int64_t n;
     unsigned char key[16];

     headerlen = PWD_VER_LENGTH + salt_length[ctx->mode];
     if ((n=zip_source_read(src, header, headerlen)) < 0) {
 	_zip_error_set_from_source(&ctx->error, src);
 	return -1;
     }

     if (n != headerlen) {
 	zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
 	return -1;
     }

     if (_zip_fcrypt_init(ctx->mode, ctx->password, strlen(ctx->password), header, password_verification, &ctx->fcrypt_ctx) != 0) {
 	zip_error_set(&ctx->error, ZIP_ER_MEMORY, 0);
 	return -1;
     }
     if (memcmp(password_verification, header + salt_length[ctx->mode], PWD_VER_LENGTH) != 0) {
 	zip_error_set(&ctx->error, ZIP_ER_WRONGPASSWD, 0);
 	return -1;
     }
     return 0;
 }


 static bool
 verify_hmac(zip_source_t *src, struct winzip_aes *ctx)
 {
     unsigned char computed[HMAC_LENGTH], from_file[HMAC_LENGTH];
     if (zip_source_read(src, from_file, HMAC_LENGTH) < HMAC_LENGTH) {
 	_zip_error_set_from_source(&ctx->error, src);
 	return false;
     }

     _zip_fcrypt_end(computed, &ctx->fcrypt_ctx);

     if (memcmp(from_file, computed, HMAC_LENGTH) != 0) {
 	zip_error_set(&ctx->error, ZIP_ER_CRC, 0);
 	return false;
     }

     return true;
 }


 static zip_int64_t
 winzip_aes_decrypt(zip_source_t *src, void *ud, void *data, zip_uint64_t len, zip_source_cmd_t cmd)
 {
     struct winzip_aes *ctx;
     zip_int64_t n;

     ctx = (struct winzip_aes *)ud;

     switch (cmd) {
     case ZIP_SOURCE_OPEN:
 	if (decrypt_header(src, ctx) < 0) {
 	    return -1;
 	}
 	ctx->current_position = 0;
 	return 0;

     case ZIP_SOURCE_READ:
 	if (len > ctx->data_length - ctx->current_position) {
 	    len = ctx->data_length - ctx->current_position;
 	}

 	if (len == 0) {
 	    if (!verify_hmac(src, ctx)) {
 		return -1;
 	    }
 	    return 0;
 	}

 	if ((n=zip_source_read(src, data, len)) < 0) {
 	    _zip_error_set_from_source(&ctx->error, src);
 	    return -1;
 	}
 	ctx->current_position += n;

 	/* TODO: loop if len > UINT_MAX */
 	_zip_fcrypt_decrypt(data, n, &ctx->fcrypt_ctx);

 	return n;

     case ZIP_SOURCE_CLOSE:
 	return 0;

     case ZIP_SOURCE_STAT:
     {
 	zip_stat_t *st;

 	st = (zip_stat_t *)data;

 	st->encryption_method = ZIP_EM_NONE;
 	st->valid |= ZIP_STAT_ENCRYPTION_METHOD;
 	if (st->valid & ZIP_STAT_COMP_SIZE) {
 	    st->comp_size -= 12 + salt_length[ctx->mode];
 	}

 	return 0;
     }

     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, -1);

     case ZIP_SOURCE_ERROR:
 	return zip_error_to_data(&ctx->error, data, len);

     case ZIP_SOURCE_FREE:
 	winzip_aes_free(ctx);
 	return 0;

     default:
 	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
 	return -1;
     }
 }


 static void
 winzip_aes_free(struct winzip_aes *ctx)
 {
     if (ctx == NULL) {
 	return;
     }

     _zip_crypto_clear(&ctx->fcrypt_ctx, sizeof(ctx->fcrypt_ctx));
     _zip_crypto_clear(ctx->password, strlen(ctx->password));
     free(ctx->password);
     zip_error_fini(&ctx->error);
     free(ctx);
 }


 static struct winzip_aes *
 winzip_aes_new(int mode, const char *password) {
     struct winzip_aes *ctx;

     if ((ctx = (struct winzip_aes *)malloc(sizeof(*ctx))) == NULL) {
 	return NULL;
     }

     if ((ctx->password = strdup(password)) == NULL) {
 	free(ctx);
 	return NULL;
     }

     ctx->mode = mode;

     zip_error_init(&ctx->error);

     return ctx;
 }
	/*
	zip_source_winzip_aes.c -- Winzip AES de/encryption routines
	Copyright (C) 2009-2015 Dieter Baron and Thomas Klausner

	This file is part of libzip, a library to manipulate ZIP archives.
	The authors can be contacted at <libzip@nih.at>

	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"

	#include "gladman-fcrypt.h"

	#define MAX_HEADER_LENGTH (16+PWD_VER_LENGTH)
	#define HMAC_LENGTH 10

	static int salt_length[] = { 0, 8, 12, 16 };

	struct winzip_aes {
	char *password;
	int mode;

	zip_uint64_t data_length;
	zip_uint64_t current_position;

	fcrypt_ctx fcrypt_ctx;
	zip_error_t error;
	};


	static int decrypt_header(zip_source_t src, struct winzip_aes ctx);
	static void winzip_aes_free(struct winzip_aes *);
	static zip_int64_t winzip_aes_decrypt(zip_source_t src, void ud, void *data, zip_uint64_t len, zip_source_cmd_t cmd);
	static struct winzip_aes * winzip_aes_new(int mode, const char *password);


	zip_source_t *
	zip_source_winzip_aes_decode(zip_t za, zip_source_t src, zip_uint16_t em, int flags, const char *password)
	{
	zip_source_t *s2;
	int mode = 0;
	zip_stat_t st;
	zip_uint64_t aux_length;
	struct winzip_aes *ctx;

	switch (em) {
	case ZIP_EM_AES_128:
	mode = 1;
	break;
	case ZIP_EM_AES_192:
	mode = 2;
	break;
	case ZIP_EM_AES_256:
	mode = 3;
	break;
	}

	if (password == NULL \|\| src == NULL \|\| mode == 0) {
	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 (zip_source_stat(src, &st) != 0) {
	_zip_error_set_from_source(&za->error, src);
	return NULL;
	}

	aux_length = PWD_VER_LENGTH + salt_length[mode] + HMAC_LENGTH;

	if ((st.valid & ZIP_STAT_COMP_SIZE) == 0 \|\| st.comp_size < aux_length) {
	zip_error_set(&za->error, ZIP_ER_OPNOTSUPP, 0);
	return NULL;
	}

	if ((ctx = winzip_aes_new(mode, password)) == NULL) {
	zip_error_set(&za->error, ZIP_ER_MEMORY, 0);
	return NULL;
	}

	ctx->data_length = st.comp_size - aux_length;

	if ((s2 = zip_source_layered(za, src, winzip_aes_decrypt, ctx)) == NULL) {
	winzip_aes_free(ctx);
	return NULL;
	}

	return s2;
	}


	static int
	decrypt_header(zip_source_t src, struct winzip_aes ctx)
	{
	zip_uint8_t header[MAX_HEADER_LENGTH];
	zip_uint8_t password_verification[PWD_VER_LENGTH];
	zip_uint8_t headerlen;
	zip_int64_t n;
	unsigned char key[16];

	headerlen = PWD_VER_LENGTH + salt_length[ctx->mode];
	if ((n=zip_source_read(src, header, headerlen)) < 0) {
	_zip_error_set_from_source(&ctx->error, src);
	return -1;
	}

	if (n != headerlen) {
	zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
	return -1;
	}

	if (_zip_fcrypt_init(ctx->mode, ctx->password, strlen(ctx->password), header, password_verification, &ctx->fcrypt_ctx) != 0) {
	zip_error_set(&ctx->error, ZIP_ER_MEMORY, 0);
	return -1;
	}
	if (memcmp(password_verification, header + salt_length[ctx->mode], PWD_VER_LENGTH) != 0) {
	zip_error_set(&ctx->error, ZIP_ER_WRONGPASSWD, 0);
	return -1;
	}
	return 0;
	}


	static bool
	verify_hmac(zip_source_t src, struct winzip_aes ctx)
	{
	unsigned char computed[HMAC_LENGTH], from_file[HMAC_LENGTH];
	if (zip_source_read(src, from_file, HMAC_LENGTH) < HMAC_LENGTH) {
	_zip_error_set_from_source(&ctx->error, src);
	return false;
	}

	_zip_fcrypt_end(computed, &ctx->fcrypt_ctx);

	if (memcmp(from_file, computed, HMAC_LENGTH) != 0) {
	zip_error_set(&ctx->error, ZIP_ER_CRC, 0);
	return false;
	}

	return true;
	}


	static zip_int64_t
	winzip_aes_decrypt(zip_source_t src, void ud, void *data, zip_uint64_t len, zip_source_cmd_t cmd)
	{
	struct winzip_aes *ctx;
	zip_int64_t n;

	ctx = (struct winzip_aes *)ud;

	switch (cmd) {
	case ZIP_SOURCE_OPEN:
	if (decrypt_header(src, ctx) < 0) {
	return -1;
	}
	ctx->current_position = 0;
	return 0;

	case ZIP_SOURCE_READ:
	if (len > ctx->data_length - ctx->current_position) {
	len = ctx->data_length - ctx->current_position;
	}

	if (len == 0) {
	if (!verify_hmac(src, ctx)) {
	return -1;
	}
	return 0;
	}

	if ((n=zip_source_read(src, data, len)) < 0) {
	_zip_error_set_from_source(&ctx->error, src);
	return -1;
	}
	ctx->current_position += n;

	/* TODO: loop if len > UINT_MAX */
	_zip_fcrypt_decrypt(data, n, &ctx->fcrypt_ctx);

	return n;

	case ZIP_SOURCE_CLOSE:
	return 0;

	case ZIP_SOURCE_STAT:
	{
	zip_stat_t *st;

	st = (zip_stat_t *)data;

	st->encryption_method = ZIP_EM_NONE;
	st->valid \|= ZIP_STAT_ENCRYPTION_METHOD;
	if (st->valid & ZIP_STAT_COMP_SIZE) {
	st->comp_size -= 12 + salt_length[ctx->mode];
	}

	return 0;
	}

	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, -1);

	case ZIP_SOURCE_ERROR:
	return zip_error_to_data(&ctx->error, data, len);

	case ZIP_SOURCE_FREE:
	winzip_aes_free(ctx);
	return 0;

	default:
	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
	return -1;
	}
	}


	static void
	winzip_aes_free(struct winzip_aes *ctx)
	{
	if (ctx == NULL) {
	return;
	}

	_zip_crypto_clear(&ctx->fcrypt_ctx, sizeof(ctx->fcrypt_ctx));
	_zip_crypto_clear(ctx->password, strlen(ctx->password));
	free(ctx->password);
	zip_error_fini(&ctx->error);
	free(ctx);
	}


	static struct winzip_aes *
	winzip_aes_new(int mode, const char *password) {
	struct winzip_aes *ctx;

	if ((ctx = (struct winzip_aes )malloc(sizeof(ctx))) == NULL) {
	return NULL;
	}

	if ((ctx->password = strdup(password)) == NULL) {
	free(ctx);
	return NULL;
	}

	ctx->mode = mode;

	zip_error_init(&ctx->error);

	return ctx;
	}