scsp - smali class shortest path

Purpose:

• apktool generates a root directory having one or more subdirectories that contain .smali files
• when the APK was built using a code obfuscator, the .smali class names are short and meaningless
• the purpose of this command-line utility is to:
  • make it easier to identify a relationship between 2 .smali classes
    • for example:
      • determine a .smali class at which to begin
        • AndroidManifest.xml specifies the main Activity for an application
      • determine a .smali class at which to end
        • strings.xml maps an error message to its string ID name
        • public.xml maps the string ID name to its hex integer ID value
        • grepping for this hex integer ID value can identify the .smali class that uses this string to display the relevant error message
      • the next step is to determine a relationship:
        • how does the main Activity reach the class that produces this error?
        • this utility helps to answer this question by showing the shortest path between the 2 .smali classes
• how exactly is the shortest path determined?
  • with a 2-step process:
    1. produce a data structure that contains a graph of all .smali classes
       • walk the file tree beginning at the root directory
       • detect .smali files
       • read each .smali file and extract a list of all other .smali classes referenced by its code
    2. query the graph data
       • using this implementation of Dijkstra's single-source shortest-paths algorithm
       • write the result to stdout

Installation:

npm install --global @warren-bank/node-smali-class-shortest-path

Usage:

scsp <options>

========
options:
========
"--help"
    Print a summary of all command-line options.

"-v"
"--version"
    Print the current version.

"-g" <filepath>
"--graph" <filepath>
    Specify path to the graph data structure

"-d" <dirpath>
"--dir" <dirpath>
    Specify path to the root directory containing .smali files

"-b" <classname>
"--begin" <classname>
    Specify .smali class name at which to begin search

"-e" <classname>
"--end" <classname>
    Specify .smali class name at which to end search

"-p"
"--pretty"
    Pretty print the shortest path result

Example:

1. produce the graph data structure (once)

     scsp --graph "/path/to/graph.json" --dir "/path/to/decoded/apk/directory"

2. query the graph data structure (repeatedly)

     scsp --graph "/path/to/graph.json" --begin "com/github/warren-bank/app/MainActivity" --end "com/github/warren-bank/app/utils/Account" -p

   • notes:
     • smali syntax wraps class name identifiers with a leading "L" and trailing ";"
       • these characters are optional for values passed to --begin and --end
       • if both are included, they are stripped to normalize format

Legal:

• copyright: Warren Bank
• license: GPL-2.0