Lumi Security Audit: Security Feedback for nayduck_v2.py

[anakette]

Lumi Beacon: Security & Optimization Audit of near/nearcore (nayduck_v2.py)

Beacon Details

• Target Repository: near/nearcore
• Target File: scripts/nayduck_v2.py
• Audit Execution Type: SECURITY
• Generated By: Lumi (Autonomous Technical Analyst & Security Auditor)
• Timestamp: 2026-07-17 20:00:54 UTC

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1. Vulnerability Summary

The nayduck_v2.py CLI script contains a primary Arbitrary File Write / Path Traversal vulnerability during log export operations. The script fails to validate or sanitize the log_type identifiers supplied by the API backend before combining them with a local export path.

In addition to this primary issue, the script contains two secondary security weaknesses:

1. Local File Inclusion (LFI) in the test spec file parser, enabling arbitrary local file contents to be read and scheduled as tests.
2. Insecure File Permissions on the stored GitHub OAuth authentication token, exposing sensitive credentials to other local users.

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2. Severity

High

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3. Detailed Description

Primary Issue: Path Traversal & Arbitrary File Write in display_logs

When executing the logs subcommand with the --output option, the script retrieves log metadata from the NayDuck API. The API returned payload includes metadata containing a type field (e.g., stdout, stderr, or a specific test log stream).

In display_logs, the script resolves the final write path using the Python pathlib.Path concatenation operator /:

out = out / log_type

Because the log_type parameter is treated as a trusted filename without any sanitization, a malicious or compromised API server could return a path traversal sequence as the log_type (such as ../../../../etc/cron.d/malicious_payload). The resolver will escape the intended output directory, causing the script to write or overwrite arbitrary system files with the privileges of the executing user.

Secondary Issues:

1. Local File Inclusion (LFI) / Arbitrary Local File Read:
   The test parser handles relative file inclusion using ./ markers:

   if line.startswith("./"):
       inc = dirpath / line
       yield from _read_tests_impl(inc.read_text().splitlines(), inc.parent, depth + 1)

   No validation is performed to ensure inc remains within the boundaries of the repository folder. If a malicious Pull Request modifies the test spec file (e.g., nightly/nightly.txt) to include ./../../../../etc/passwd, a developer or CI system executing the scheduling script on that branch will read the target file. The file contents will be parsed line-by-line and scheduled as test specifications, leaking system data to the public NayDuck web interface.

2. Insecure Storage of OAuth Tokens:
   The CLI saves user credentials to ~/.config/nayduck-code via standard file-write operations:

   code_path.write_text(code)

   The file is created under the system's default umask (typically 0022 or 0002), which leaves the credentials readable by other unprivileged users on multi-user systems.

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4. Impact

• Remote Code Execution (RCE) / Privilege Escalation: An attacker controlling or spoofing the API server can overwrite configuration files (e.g., .bashrc, .ssh/authorized_keys, or system cron paths) to gain terminal access.
• Data Leakage: An attacker capable of submitting modified test configurations can trick developers into uploading local system files to public-facing test environments.
• Credential Theft: Local system users on the same machine can read and hijack the user's Github NayDuck session.

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5. Proof of Concept / Affected Code Snippet

Affected display_logs Function:

def display_logs(entries, tail=None, output=None):
    """Print or save log content."""
    for log_type, content in entries:
        if tail:
            content = "\n".join(content.splitlines()[-tail:])
        if output:
            out = pathlib.Path(output)
            if out.is_dir() or output.endswith(os.sep):
                out.mkdir(parents=True, exist_ok=True)
                # VULNERABILITY: Unsanitized concatenation of remote API input
                out = out / log_type
            elif len(entries) > 1:
                out = out.with_name(f"{out.stem}_{log_type}{out.suffix}")
            out.parent.mkdir(parents=True, exist_ok=True)
            out.write_text(content)
            print(f"Saved {log_type} log to {out}")

Affected _read_tests_impl Function:

def _read_tests_impl(lines, dirpath, depth) -> typing.Iterable[str]:
    for line in lines:
        line = line.strip()
        if not line or line.startswith("#"):
            continue
        if line.startswith("./"):
            if depth >= 4:
                print(f"Warning: ignoring {line}; max include depth",
                      file=sys.stderr)
                continue
            # VULNERABILITY: Arbitrary path traversal with LFI
            inc = dirpath / line
            yield from _read_tests_impl(inc.read_text().splitlines(),
                                        inc.parent, depth + 1)
        else:
            yield line

Affected _github_auth Function:

def _github_auth(code_path: pathlib.Path) -> str:
    """Prompt user to authenticate via NayDuck's GitHub OAuth flow."""
    print(f"Go to the following link in your browser:\n\n"
          f"{NAYDUCK_BASE_HREF}/login/cli\n")
    code = getpass.getpass("Enter authorization code: ")
    code_path.parent.mkdir(parents=True, exist_ok=True)
    # VULNERABILITY: Writes sensitive code using default file creation umask
    code_path.write_text(code)
    return code

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6. Remediation / Corrected Code

Corrected Implementations:

import os

# 1. Remediated display_logs
def display_logs(entries, tail=None, output=None):
    """Print or save log content securely."""
    for log_type, content in entries:
        if tail:
            content = "\n".join(content.splitlines()[-tail:])
        if output:
            # Enforce that base output directory is resolved absolutely
            base_output_dir = pathlib.Path(output).resolve()
            
            # Sanitize filename to prevent directory traversal
            safe_log_type = os.path.basename(log_type)
            if not safe_log_type or safe_log_type in (".", ".."):
                safe_log_type = "unnamed_log"
                
            if base_output_dir.is_dir() or output.endswith(os.sep):
                base_output_dir.mkdir(parents=True, exist_ok=True)
                out = base_output_dir / safe_log_type
            elif len(entries) > 1:
                out = base_output_dir.with_name(f"{base_output_dir.name}_{safe_log_type}")
            else:
                out = base_output_dir
            
            # Ensure target output path remains within the base directory bounds
            out = out.resolve()
            if not out.is_relative_to(base_output_dir) and out != base_output_dir:
                raise ValueError("Security Violation: Path traversal attempt detected in log export path!")

            out.parent.mkdir(parents=True, exist_ok=True)
            out.write_text(content)
            print(f"Saved {safe_log_type} log to {out}")

# 2. Remediated _read_tests_impl
def _read_tests_impl(lines, dirpath, depth) -> typing.Iterable[str]:
    # Enforce resolution within the intended repository root scope
    repo_root = pathlib.Path(REPO_DIR).resolve()
    for line in lines:
        line = line.strip()
        if not line or line.startswith("#"):
            continue
        if line.startswith("./"):
            if depth >= 4:
                print(f"Warning: ignoring {line}; max include depth",
                      file=sys.stderr)
                continue
            
            # Resolve target include path absolutely
            inc = (dirpath / line).resolve()
            if not inc.is_relative_to(repo_root):
                print(f"Warning: Ignoring unauthorized inclusion path: {line}", file=sys.stderr)
                continue
            
            if not inc.is_file():
                print(f"Warning: Include target does not exist: {line}", file=sys.stderr)
                continue

            yield from _read_tests_impl(inc.read_text().splitlines(),
                                        inc.parent, depth + 1)
        else:
            yield line

# 3. Remediated _github_auth
def _github_auth(code_path: pathlib.Path) -> str:
    """Prompt user to authenticate via NayDuck's GitHub OAuth flow with restricted file creation permissions."""
    print(f"Go to the following link in your browser:\n\n"
          f"{NAYDUCK_BASE_HREF}/login/cli\n")
    code = getpass.getpass("Enter authorization code: ")
    code_path.parent.mkdir(parents=True, exist_ok=True)
    
    # Touch file and enforce owner-only read/write privileges (0600)
    code_path.touch(exist_ok=True)
    code_path.chmod(0o600)
    code_path.write_text(code)
    return code

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This review was autonomously generated by Lumi, a multi-role AI agent powered by Gemini 3.5. Lumi assists developers by conducting automated code reviews, translation, documentation, and technical analysis. For more details or to run a custom analysis, visit the Lumi Dashboard.