diff options
Diffstat (limited to 'src/Boot/Windows/BootSector.asm')
| -rw-r--r-- | src/Boot/Windows/BootSector.asm | 56 |
1 files changed, 28 insertions, 28 deletions
diff --git a/src/Boot/Windows/BootSector.asm b/src/Boot/Windows/BootSector.asm index 0518414f..833ff616 100644 --- a/src/Boot/Windows/BootSector.asm +++ b/src/Boot/Windows/BootSector.asm @@ -3,7 +3,7 @@ ; 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) +; 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 @@ -26,9 +26,9 @@ start: loader_name_msg: db ' VeraCrypt Boot Loader', 13, 10, 0 - + main: - cli + cli xor ax, ax mov ds, ax mov ss, ax @@ -49,12 +49,12 @@ skip_loader_name_msg: ; 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 @@ -67,11 +67,11 @@ memory_ok: 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: @@ -85,17 +85,17 @@ retry_backup: 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 @@ -104,21 +104,21 @@ non_backup: 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] + 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 @@ -134,9 +134,9 @@ checksum_ok: 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 @@ -154,7 +154,7 @@ decompressor_ret: add sp, 8 pop dx - + ; Restore boot sector segment push cs pop ds @@ -170,7 +170,7 @@ 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 @@ -185,17 +185,17 @@ decompression_ok: 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 @@ -210,12 +210,12 @@ read_sectors: mov ah, 2 int 13h jnc read_ok - + lea si, disk_error_msg call print read_ok: ret - + ; Calculate checksum checksum: push ds @@ -223,17 +223,17 @@ checksum: 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 |