diff options
Diffstat (limited to 'src/Boot/Windows/BootSector.asm')
| -rw-r--r-- | src/Boot/Windows/BootSector.asm | 35 |
1 files changed, 18 insertions, 17 deletions
diff --git a/src/Boot/Windows/BootSector.asm b/src/Boot/Windows/BootSector.asm index 833ff616..0d2bbdca 100644 --- a/src/Boot/Windows/BootSector.asm +++ b/src/Boot/Windows/BootSector.asm @@ -3,9 +3,9 @@ ; 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 all other portions of this file are Copyright (c) 2013-2017 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. ; @@ -42,25 +42,26 @@ main: 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 + ; Determine boot loader segment + mov ax, word ptr [ds:413h] ;available kB from BIOS + sub ax, TC_BOOT_MEMORY_REQUIRED ;minus TC_BOOT_MEMORY_REQUIRED + jc mem_toolow + and ax, 0FFE0h ;32K align + shl ax, 6 ;convert kB to segment addr (*1024/16) + cmp ax, 8000h + jb mem_toolow ;we can't load below 8000h + cmp ax, TC_BOOT_LOADER_SEGMENT + jbe memory_ok ;don't load above TC_BOOT_LOADER_SEGMENT (9000h) + mov ax, TC_BOOT_LOADER_SEGMENT + jmp memory_ok + +mem_toolow: + mov ax, TC_BOOT_LOADER_LOWMEM_SEGMENT memory_ok: - mov es, ax + mov es, ax ; Clear BSS section xor al, al mov di, TC_COM_EXECUTABLE_OFFSET @@ -137,9 +138,9 @@ checksum_ok: push dx ; Decompress boot loader - mov cx, word ptr [start + TC_BOOT_SECTOR_LOADER_LENGTH_OFFSET] + mov cx, word ptr cs:[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 |