patchelf

Warnings

• gotcha The `patchelf` package on PyPI provides the command-line utility, not a direct Python API for ELF manipulation. Interaction with ELF files should be done by executing the `patchelf` binary via `subprocess.run()`.
  Fix: Always use `subprocess.run()` to invoke the `patchelf` command-line tool within your Python scripts. Avoid searching for direct Python imports or classes within the `patchelf` package.
• gotcha The project actively maintains multiple release branches (e.g., 0.15.x, 0.17.x, 0.18.x). Bug fixes and minor features are often backported to older maintenance branches, meaning a seemingly 'older' minor version might contain recent critical fixes.
  Fix: Refer to the GitHub releases page for `patchelf` to understand the specific changes and backports included in each version. For critical applications, ensure you are using the latest stable release that includes all necessary security and stability fixes.
• gotcha Directly modifying ELF executables is a low-level and potentially destructive operation. Incorrect usage can corrupt binaries, leading to crashes, unexpected behavior, or rendering them unexecutable.
  Fix: Always back up your ELF files before attempting any modifications with `patchelf`. Thoroughly test modified binaries in a controlled environment to ensure their integrity and functionality.
• breaking Several critical out-of-bounds read/write vulnerabilities in functions like `modifySoname` and `modifyRPath` have been fixed in recent maintenance and feature releases. Older versions are susceptible to silent corruption or crashes.
  Fix: Upgrade to at least `patchelf 0.17.1` (for `modifySoname` fixes) or `patchelf 0.15.5` (for `modifySoname` backports and general stability fixes). If modifying RPATH, ensure at least `0.15.3` or newer is used.

Install

• pip install patchelf Install patchelf

Imports

• CLI tool

  import subprocess
  subprocess.run(['patchelf', '--print-rpath', '/path/to/executable'], check=True)

  The 'patchelf' package on PyPI primarily provides the command-line utility, not a Python library API for direct import and manipulation. Its functionality is accessed by executing the 'patchelf' binary via subprocess calls.

Quickstart

This quickstart demonstrates how to use the `patchelf` command-line utility from Python to modify the RPATH of an ELF executable. It first creates a dummy executable (requires a C compiler like GCC or Clang), prints its original RPATH (if any), sets a new RPATH, and then prints the modified RPATH.

import subprocess
import os

# Create a dummy executable for demonstration (requires clang/gcc)
# In a real scenario, you'd use an existing ELF binary.
with open('my_test_program.c', 'w') as f:
    f.write('int main() { return 0; }')
subprocess.run(['gcc', '-o', 'my_executable', 'my_test_program.c'], check=True)

print("Original RPATH:")
try:
    result = subprocess.run(['patchelf', '--print-rpath', './my_executable'], capture_output=True, text=True, check=True)
    print(result.stdout.strip())
except subprocess.CalledProcessError as e:
    if 'has no RPATH' in e.stderr:
        print('No RPATH found.')
    else:
        raise

print("\nSetting RPATH to '$ORIGIN/lib'")
subprocess.run(['patchelf', '--set-rpath', '$ORIGIN/lib', './my_executable'], check=True)

print("\nNew RPATH:")
result = subprocess.run(['patchelf', '--print-rpath', './my_executable'], capture_output=True, text=True, check=True)
print(result.stdout.strip())

# Clean up dummy files
os.remove('my_test_program.c')
os.remove('my_executable')