DDisasm is a fast disassembler which is accurate enough for the resulting assembly code to be reassembled. DDisasm is implemented using the datalog (souffle) declarative logic programming language to compile disassembly rules and heuristics. The disassembler first parses ELF file information and decodes a superset of possible instructions to create an initial set of datalog facts. These facts are analyzed to identify code location, symbolization, and function boundaries. The results of this analysis, a refined set of datalog facts, are then translated to the GTIRB intermediate representation for binary analysis and reverse engineering. The GTIRB pretty printer may then be used to pretty print the GTIRB to reassemblable assembly code.

Use the grammatech/ddisasm Docker image to try out ddisasm quickly.

ddisasm uses C++17, and requires a compiler which supports that standard such as gcc 7, clang 6, or MSVC 2017.

To build and install ddisasm, the following requirements should be installed:

• gtirb
• gtirb-pprinter
• Capstone, version 4.0.1 or later
• Souffle, version 2.2
  • Must be configured with support for 64 bit numbers (via -DSOUFFLE_DOMAIN_64BIT=1 during configuration)
• libehp, version 1.0.0 or higher
• LIEF, version 0.11.5 or higher

Note that these versions are newer than what your package manager may provide by default: This is true on Ubuntu 18, Debian 10, and others. Prefer building these dependencies from sources to avoid versioning problems. Alternatively, you can use the GrammaTech PPA to get the correct versions of the dependencies. See the GTIRB readme for instructions on using the GrammaTech PPA.

Use the following options to configure cmake:

• You can tell CMake which compiler to use with -DCMAKE_CXX_COMPILER=<compiler>.

• You can tell CMake about the paths to its dependencies as follows:

• ddisasm can make use of GTIRB in static library form (instead of shared library form, the default) if you use the flag -DDDISASM_BUILD_SHARED_LIBS=OFF.

Once the dependencies are installed, you can configure and build as follows:

$ cmake ./ -Bbuild
$ cd build
$ make

One can selectively turn off ddisasm's various architecture support modules to speed up compilation time during development. For example:

$ cmake ./ -Bbuild -DDDISASM_ARM_64=OFF -DDDISASM_X86_32=OFF

will deactivate ARM_64 and X86_32 support.

For accelerated development of datalog logic, ddisasm can also execute the souffle interpreter. To invoke the interpreter, specify a --debug-dir directory path and the --intepreter parameter with the path of ddisasm's datalog entry.

For example:

$ cd ddisasm/examples/ex1
$ make
$ mkdir dbg
$ ddisasm --debug-dir dbg --interpreter ../../src/datalog/main.dl --asm ex.s ex

See the GTIRB readme.

Once ddisasm is built, we can run complete analysis on a file by calling build/bin/ddisasm'. For example, we can run the analysis on one of the examples as follows:

cd build/bin && ./ddisasm ../../examples/ex1/ex --asm ex.s

Ddisasm accepts the following parameters:

--help : produce help message

--ir arg : GTIRB output file

--json arg : GTIRB json output file

--asm arg : ASM output file

--debug : if the assembly code is printed, it is printed with debugging information

--debug-dir arg : location to write CSV files for debugging

-K [ --keep-functions ] arg : Print the given functions even if they are skipped by default (e.g. _start)

--self-diagnose : This option is useful for debugging. Use relocation information to emit a self diagnosis of the symbolization process. This option only works if the target binary contains complete relocation information. You can enable that in ld using the option --emit-relocs.

-F [ --skip-function-analysis ] : Skip additional analyses to compute more precise function boundaries.

-j [ --threads ] : Number of cores to use. It is set to the number of cores in the machine by default.

-I [ --interpreter ] arg : Execute the souffle interpreter with the specified source file.

The directory tests/ contains the script reassemble_and_test.sh to rewrite and test a complete project. reassemble_and_test.sh rebuilds a project using the compiler and compiler flags specified in the enviroment variables CC and CFLAGS (make -e), rewrites the binary and run the project tests on the new binary.

We can rewrite ex1 as follows:

cd examples/ex1
make
ddisasm ex --asm ex.s
gcc ex.s -o ex_rewritten

The directory tests/ also contains a script test_small.sh for rewriting the examples in /examples with different compilers and optimization flags.

Please read the DDisasm Code of Conduct.

Please follow the Code Requirements in gtirb/CONTRIBUTING.

We ask that all contributors complete our Contributor License Agreement (CLA), which can be found at GrammaTech-CLA-ddisasm.pdfGTIRB.pdf, and email the completed form to [email protected]. Under this agreement contributors retain the copyright to their work but grants GrammaTech unlimited license to the work.

• Programming Language Group, The University of Sydney: Initial support for ARM64.

ddisasm generates the following AuxData tables:

1. Datalog Disassembly

2. Souffle

3. Capstone disassembler

4. Control Flow Integrity for COTS Binaries

5. Alias analysis for Assembly

6. Reassembleable Disassembling

7. Ramblr: Making reassembly great again

8. An In-Depth Analysis of Disassembly on Full-Scale x86/x64 Binaries

9. Binary Code is Not Easy