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Introduction

dwarf2json is a Go utility that processes files containing symbol and type information to generate Volatility3 Intermediate Symbol File (ISF) JSON output suitable for Linux and macOS analysis.

build

To build (Go 1.18+ required):

  $ go build

To run:

  $ ./dwarf2json --help
  Usage: ./dwarf2json COMMAND

  A tool for generating intermediate symbol file (ISF)

  Commands:
    linux  generate ISF for Linux analysis
    mac    generate ISF for macOS analysis

  Options:
  -h, --help     Show this screen.
  -v, --version  Show tool and output schema version.

Note: processing large DWARF files requires a minimum of 8GB RAM.

Linux Processing

dwarf2json supports processing DWARF and symbol table information from ELF files and symbols from System.map input files to produce ISF for Linux analysis.

The user is able to select whether to include symbol, type, or both for each input file.

  $ ./dwarf2json linux --help
  Usage: dwarf2json linux [OPTIONS]

        --elf PATH           ELF file PATH to extract symbol and type information
        --elf-symbols PATH   ELF file PATH to extract only symbol information
        --elf-types PATH     ELF file PATH to extract only type information
        --system-map PATH    System.Map file PATH to extract symbol information

For example, to include symbols and types for a given Linux kernel DWARF file can be done with:

  $ ./dwarf2json linux --elf /usr/lib/debug/boot/vmlinux-4.4.0-137-generic > output.json

Symbol offsets for symbols extracted from symbol table information take precedence over those extracted from DWARF information. Thus, symbols extracted from files specified with --elf-symbols flag take precedence over symbols extracted from files specified with --elf. Symbol offsets for symbols from System.Map, specified with --system-map flag, are the highest precedence. If there is a conflict between the different symbol information sources, the offset from System.Map will be used.

Providing multiple input files for a given flag is allowed. For example, ./dwarf2json --elf file1 --elf file2 ... would process both file1 and file2. When conflicting symbol or type information is encountered, the data from the last file specified in the command invocation would take precedence.

MacOS Processing

dwarf2json supports processing DWARF and symbol table information from Mach-O files to produce ISF for macOS analysis.

The user is able to select whether to include symbol, type, or both for each input file.

  $ ./dwarf2json mac --help
  Usage: dwarf2json mac [OPTIONS]

        --arch NAME            architecture for universal FAT files. NAME is one of {i386|x86_64}
        --macho PATH           Mach-O file PATH to extract symbol and type information
        --macho-symbols PATH   Mach-O file PATH to extract only symbol information
        --macho-types PATH     Mach-O file PATH to extract only type information

For example, to include symbols and types for a given macOS kernel DWARF file and symbols from a macOS kernel can be done with:

  $ ./dwarf2json mac --macho /path/kernel.dSYM/Contents/Resources/DWARF/kernel \
    --macho-symbols /path/kernel > output.json

Symbol offsets for symbols extracted from symbol table information take precedence over those extracted from DWARF information. Thus, symbols extracted from files specified with --macho-symbols flag take precedence over symbols extracted from files specified with --macho.

Providing multiple input files for a given flag is allowed. For example, ./dwarf2json --macho file1 --macho file2 ... would process both file1 and file2. When conflicting symbol or type information is encountered, the data from the last file specified in the command invocation would take precedence.

When processing Mach-O universal FAT binaries, the --arch flag needs to be used to select the architecture for one of the embedded Mach-O files.

For example, generating ISF JSON file for i386 architecture of a OS X 10.7 kernel debug kit can be done with:

  $ ./dwarf2json mac --arch i386 \
  --macho mach_kernel.dSYM/Contents/Resources/DWARF/mach_kernel \
  --macho-symbols mach_kernel > mach_kernel.json