reasm 0.1.0

Binary tools for various formats (e.g. MZ)

reasm

Install

pip3 install reasm

Tools

MZ

mzinfo

Shows information about executable in JSON format. In particular, it determines compiler and memory model.

% mzinfo --help
usage: mzinfo [-h] [--hex] [--fast] [--content] [--indent INDENT] [--max-width MAX_WIDTH] path

positional arguments:
  path                  path to executable file

options:
  -h, --help            show this help message and exit
  --hex                 hexadecimal output
  --fast                skip long checks
  --content             output content
  --indent INDENT       indent
  --max-width MAX_WIDTH
                        max width

Useful flags:

• --hex is most useful for humans, the tool outputs JSON with numbers as decimals by default;
• --content outputs full content of sections (segments), it may produce too large outputs;
• --fast removes checks for compiler at the moment, it is currently made in non-efficient way and it shall be rewritten using Aho-Corasick algorithm, which shall also reduce code size;
• --indent controls output JSON indentation;
• --max-width formats lists in JSON to the specified width as they may be long and inconvenient to read, it is also worth mentioning that looking for a reliable way to apply such formatting, it was made it such way that it has negligible chance of failing (giving an error), so when running from a tool, --max-width=0 is preferred. It is not quite efficient too but it takes only ~20ms on typical executable and can be rewritten using API which can work with deque-like strings.

mzfix

The tool can manipulate executables on low level. The following operations are supported:

• set-entry-point <cs> <ip>;
• set-stack <ss> <sp>;
• set-minimum-allocation <size>;
• set-maximum-allocation <size>;
• set-relocations <offset>...;
• strip-tail;
• add-text-size <size>;
• fix-text-size [<fill>];
• fill-last-page [<fill>];
• preallocate-minimum [<fill>].

Example:

% mzfix XEEN.DAT XEEN0.DAT fill-last-page 'last-page\0' # Filled text up to nearest (next) page.
% mzfix XEEN0.DAT XEEN1.DAT add-text-size 128           # Increased text size by 8 paragraphs.
% mzfix XEEN1.DAT XEEN2.DAT fix-text-size 'new-page\0'  # Added space according to that size.
% xxd -g 4 -c 32 XEEN2.DAT | tail
0005c140: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000  ................................
0005c160: c7065c00 504b8cd8 05100050 b8000050 cb6c6173 742d7061 6765006c 6173742d  ..\.PK.....P...P.last-page.last-
0005c180: 70616765 006c6173 742d7061 6765006c 6173742d 70616765 006c6173 742d7061  page.last-page.last-page.last-pa
0005c1a0: 6765006c 6173742d 70616765 006c6173 742d7061 6765006c 6173742d 70616765  ge.last-page.last-page.last-page
0005c1c0: 006c6173 742d7061 6765006c 6173742d 70616765 006c6173 742d7061 6765006c  .last-page.last-page.last-page.l
0005c1e0: 6173742d 70616765 006c6173 742d7061 6765006c 6173742d 70616765 006c6173  ast-page.last-page.last-page.las
0005c200: 6e65772d 70616765 006e6577 2d706167 65006e65 772d7061 6765006e 65772d70  new-page.new-page.new-page.new-p
0005c220: 61676500 6e65772d 70616765 006e6577 2d706167 65006e65 772d7061 6765006e  age.new-page.new-page.new-page.n
0005c240: 65772d70 61676500 6e65772d 70616765 006e6577 2d706167 65006e65 772d7061  ew-page.new-page.new-page.new-pa
0005c260: 6765006e 65772d70 61676500 6e65772d 70616765 006e6577 2d706167 65006e65  ge.new-page.new-page.new-page.ne

NE

Under construction.

LE/LX

Under construction.

PE

Under construction.

ELF

Under construction.

Mach-O

Under construction.

OMF

Under construction.

RES

Under construction.

COFF

Under construction.

CV

Under construction.

DWARF

Under construction.

FLIRT

Under construction. Meanwhile, see siginfo.

Contributions

Feel free to contribute, there are some rules however:

• we are aimed at correctness first, performance is second;
• we honor PEP-8, but put PEP-20 above it;
• chaotic changes of APIs are discouraged, the chaos itself is good though;
• we appreciate retro software and technologies but utilize modern ones when appropriate;
• we wouldn't use Black but Lack instead, pytest is strictly forbidden no matter what;
• we don't like crappy dependencies and creepy toolsets;
• we are against of “graphomania”, “not invented here” and “premature refactoring” patterns;
• this is a bad choice for college project.