VeraCrypt
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path: root/src/Common/libzip/zip_file_get_comment.c
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/*
  zip_file_get_comment.c -- get file comment
  Copyright (C) 2006-2019 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 "zipint.h"

/* lenp is 32 bit because converted comment can be longer than ZIP_UINT16_MAX */

ZIP_EXTERN const char *
zip_file_get_comment(zip_t *za, zip_uint64_t idx, zip_uint32_t *lenp, zip_flags_t flags) {
    zip_dirent_t *de;
    zip_uint32_t len;
    const zip_uint8_t *str;

    if ((de = _zip_get_dirent(za, idx, flags, NULL)) == NULL)
	return NULL;

    if ((str = _zip_string_get(de->comment, &len, flags, &za->error)) == NULL)
	return NULL;

    if (lenp)
	*lenp = len;

    return (const char *)str;
}
44dd; background-color: #fff0f0 } /* Literal.String.Escape */ .highlight .sh { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Heredoc */ .highlight .si { color: #3333bb; background-color: #fff0f0 } /* Literal.String.Interpol */ .highlight .sx { color: #22bb22; background-color: #f0fff0 } /* Literal.String.Other */ .highlight .sr { color: #008800; background-color: #fff0ff } /* Literal.String.Regex */ .highlight .s1 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Single */ .highlight .ss { color: #aa6600; background-color: #fff0f0 } /* Literal.String.Symbol */ .highlight .bp { color: #003388 } /* Name.Builtin.Pseudo */ .highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */ .highlight .vc { color: #336699 } /* Name.Variable.Class */ .highlight .vg { color: #dd7700 } /* Name.Variable.Global */ .highlight .vi { color: #3333bb } /* Name.Variable.Instance */ .highlight .vm { color: #336699 } /* Name.Variable.Magic */ .highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */
;
; Derived from source code of TrueCrypt 7.1a, which is
; Copyright (c) 2008-2012 TrueCrypt Developers Association and which is governed
; by the TrueCrypt License 3.0.
;
; Modifications and additions to the original source code (contained in this file) 
; and all other portions of this file are Copyright (c) 2013-2016 IDRIX
; and are governed by the Apache License 2.0 the full text of which is
; contained in the file License.txt included in VeraCrypt binary and source
; code distribution packages.
;

.MODEL tiny
.386
_TEXT SEGMENT USE16

INCLUDE BootDefs.i

ORG 7C00h	; Standard boot sector offset

start:
	; BIOS executes boot sector from 0:7C00 or 7C0:0000 (default CD boot loader address).
	; Far jump to the next instruction sets IP to the standard offset 7C00.
	db 0EAh				; jmp 0:main
	dw main, 0

loader_name_msg:
	db ' VeraCrypt Boot Loader', 13, 10, 0
	
main:
	cli	
	xor ax, ax
	mov ds, ax
	mov ss, ax
	mov sp, 7C00h
	sti

	; Display boot loader name
	test byte ptr [start + TC_BOOT_SECTOR_USER_CONFIG_OFFSET], TC_BOOT_USER_CFG_FLAG_SILENT_MODE
	jnz skip_loader_name_msg

	lea si, loader_name_msg
	call print
skip_loader_name_msg:

	; Determine boot loader segment
	mov ax, TC_BOOT_LOADER_SEGMENT

	; Check available memory
	cmp word ptr [ds:413h], TC_BOOT_LOADER_SEGMENT / 1024 * 16 + TC_BOOT_MEMORY_REQUIRED
	jge memory_ok
	
	mov ax, TC_BOOT_LOADER_SEGMENT_LOW
	
	cmp word ptr [ds:413h], TC_BOOT_LOADER_SEGMENT_LOW / 1024 * 16 + TC_BOOT_MEMORY_REQUIRED
	jge memory_ok
	
	; Insufficient memory
	mov ax, TC_BOOT_LOADER_LOWMEM_SEGMENT

memory_ok:
	mov es, ax

	; Clear BSS section
	xor al, al
	mov di, TC_COM_EXECUTABLE_OFFSET
	mov cx, TC_BOOT_MEMORY_REQUIRED * 1024 - TC_COM_EXECUTABLE_OFFSET - 1
	cld
	rep stosb
	
	mov ax, es
	sub ax, TC_BOOT_LOADER_DECOMPRESSOR_MEMORY_SIZE / 16	; Decompressor segment
	mov es, ax
	
	; Load decompressor
	mov cl, TC_BOOT_LOADER_DECOMPRESSOR_START_SECTOR
retry_backup:
	mov al, TC_BOOT_LOADER_DECOMPRESSOR_SECTOR_COUNT
	mov bx, TC_COM_EXECUTABLE_OFFSET
	call read_sectors

	; Decompressor checksum
	xor ebx, ebx
	mov si, TC_COM_EXECUTABLE_OFFSET
	mov cx, TC_BOOT_LOADER_DECOMPRESSOR_SECTOR_COUNT * TC_LB_SIZE
	call checksum
	push ebx
	
	; Load compressed boot loader
	mov bx, TC_BOOT_LOADER_COMPRESSED_BUFFER_OFFSET
	mov cl, TC_BOOT_LOADER_START_SECTOR
	mov al, TC_MAX_BOOT_LOADER_SECTOR_COUNT
	
	test backup_loader_used, 1
	jz non_backup
	mov al, TC_BOOT_LOADER_BACKUP_SECTOR_COUNT - TC_BOOT_LOADER_DECOMPRESSOR_SECTOR_COUNT
	mov cl, TC_BOOT_LOADER_START_SECTOR + TC_BOOT_LOADER_BACKUP_SECTOR_COUNT
	
non_backup:
	call read_sectors

	; Boot loader checksum
	pop ebx
	mov si, TC_BOOT_LOADER_COMPRESSED_BUFFER_OFFSET
	mov cx, word ptr [start + TC_BOOT_SECTOR_LOADER_LENGTH_OFFSET]
	call checksum
	
	; Verify checksum
	cmp ebx, dword ptr [start + TC_BOOT_SECTOR_LOADER_CHECKSUM_OFFSET]	
	je checksum_ok

	; Checksum incorrect - try using backup if available
	test backup_loader_used, 1
	jnz loader_damaged
	
	mov backup_loader_used, 1
	mov cl, TC_BOOT_LOADER_DECOMPRESSOR_START_SECTOR + TC_BOOT_LOADER_BACKUP_SECTOR_COUNT
	
	test TC_BOOT_CFG_FLAG_BACKUP_LOADER_AVAILABLE, byte ptr [start + TC_BOOT_SECTOR_CONFIG_OFFSET]
	jnz retry_backup
	
loader_damaged:
	lea si, loader_damaged_msg
	call print
	lea si, loader_name_msg
	call print
	jmp $
checksum_ok:

	; Set up decompressor segment
	mov ax, es
	mov ds, ax
	cli
	mov ss, ax
	mov sp, TC_BOOT_LOADER_DECOMPRESSOR_MEMORY_SIZE
	sti
	
	push dx
	
	; Decompress boot loader
	mov cx, word ptr [start + TC_BOOT_SECTOR_LOADER_LENGTH_OFFSET]
	sub cx, TC_GZIP_HEADER_SIZE
	push cx																		; Compressed data size
	push TC_BOOT_LOADER_COMPRESSED_BUFFER_OFFSET + TC_GZIP_HEADER_SIZE			; Compressed data
	push TC_MAX_BOOT_LOADER_DECOMPRESSED_SIZE									; Output buffer size
	push TC_BOOT_LOADER_DECOMPRESSOR_MEMORY_SIZE + TC_COM_EXECUTABLE_OFFSET		; Output buffer

	push cs
	push decompressor_ret
	push es
	push TC_COM_EXECUTABLE_OFFSET
	retf
decompressor_ret:

	add sp, 8
	pop dx
	
	; Restore boot sector segment
	push cs
	pop ds

	; Check decompression result
	test ax, ax
	jz decompression_ok

	lea si, loader_damaged_msg
	call print
	jmp $
decompression_ok:

	; DH = boot sector flags
	mov dh, byte ptr [start + TC_BOOT_SECTOR_CONFIG_OFFSET]
	
	; Set up boot loader segment
	mov ax, es
	add ax, TC_BOOT_LOADER_DECOMPRESSOR_MEMORY_SIZE / 16
	mov es, ax
	mov ds, ax
	cli
	mov ss, ax
	mov sp, TC_BOOT_LOADER_STACK_TOP
	sti

	; Execute boot loader
	push es
	push TC_COM_EXECUTABLE_OFFSET
	retf
	
	; Print string
print:
	xor bx, bx
	mov ah, 0eh
	cld
	
@@:	lodsb
	test al, al
	jz print_end
	
	int 10h
	jmp @B

print_end:
	ret

	; Read sectors of the first cylinder
read_sectors:
	mov ch, 0           ; Cylinder
	mov dh, 0           ; Head
						; DL = drive number passed from BIOS
	mov ah, 2
	int 13h
	jnc read_ok
	
	lea si, disk_error_msg
	call print
read_ok:
	ret
	
	; Calculate checksum
checksum:
	push ds
	push es
	pop ds
	xor eax, eax
	cld
	
@@:	lodsb
	add ebx, eax
	rol ebx, 1
	loop @B
	
	pop ds
	ret

backup_loader_used		db 0
	
disk_error_msg			db 'Disk error', 13, 10, 7, 0
loader_damaged_msg		db 7, 'Loader damaged! Repair with Rescue Disk', 0

ORG 7C00h + 510
	dw 0AA55h			; Boot sector signature

_TEXT ENDS
END start