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BUG-HUNT: [security] changeset.py _file_hash reads files without sandbox boundary check — path traversal leaks file hashes #7480

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opened 2026-04-10 20:45:28 +00:00 by HAL9000 · 2 comments

HAL9000 commented

2026-04-10 20:45:28 +00:00

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Bug Report: Security — Path Traversal in `_file_hash` Reads Files Outside Sandbox

Severity Assessment

Impact: SHA-256 hashes of arbitrary system files stored in changeset entries — information leakage
Likelihood: Medium — requires crafted path in tool input
Priority: High

Location

File: src/cleveragents/tool/builtins/changeset.py
Function: _file_hash
Lines: 113–118
Category: security (path traversal)

Description

_file_hash constructs a resolved path using the sandbox root but performs no boundary check. A tool input with path="../../../etc/passwd" would compute and return the SHA-256 hash of that file. The hash is stored in ChangeSetEntry, potentially exposing system file metadata. Unlike file_tools.validate_path, this function silently reads any accessible file.

Evidence

def _file_hash(path_str: str, sandbox_root: str | None = None) -> str | None:
    root = Path(sandbox_root) if sandbox_root else Path.cwd()
    p = (root / path_str).resolve()
    if not p.exists():
        return None
    return hashlib.sha256(p.read_bytes()).hexdigest()  # ← reads without boundary validation

A call like _file_hash("../../../etc/shadow", "/sandbox/plan123") would:

root = /sandbox/plan123
p resolves to /etc/shadow
No boundary check performed
SHA-256 of /etc/shadow returned and stored in the changeset

Expected Behavior

_file_hash should refuse to hash files outside the sandbox root and return None for out-of-bounds paths.

Actual Behavior

Files anywhere on the filesystem (that the process can read) are hashed without restriction.

Suggested Fix

def _file_hash(path_str: str, sandbox_root: str | None = None) -> str | None:
    root = (Path(sandbox_root) if sandbox_root else Path.cwd()).resolve()
    p = (root / path_str).resolve()
    if not p.is_relative_to(root):   # boundary guard
        return None
    if not p.exists():
        return None
    return hashlib.sha256(p.read_bytes()).hexdigest()

TDD Note

After this bug issue is verified, a corresponding Type/Testing issue will be created for TDD. The test will use tags: @tdd_issue, @tdd_issue_, and @tdd_expected_fail to prove the bug exists before fixing it.

Automated by CleverAgents Bot
Supervisor: Bug Detection Pool | Agent: bug-hunt-pool-supervisor

## Bug Report: Security — Path Traversal in `_file_hash` Reads Files Outside Sandbox ### Severity Assessment - **Impact**: SHA-256 hashes of arbitrary system files stored in changeset entries — information leakage - **Likelihood**: Medium — requires crafted path in tool input - **Priority**: High ### Location - **File**: `src/cleveragents/tool/builtins/changeset.py` - **Function**: `_file_hash` - **Lines**: 113–118 - **Category**: security (path traversal) ### Description `_file_hash` constructs a resolved path using the sandbox root but performs **no boundary check**. A tool input with `path="../../../etc/passwd"` would compute and return the SHA-256 hash of that file. The hash is stored in `ChangeSetEntry`, potentially exposing system file metadata. Unlike `file_tools.validate_path`, this function silently reads any accessible file. ### Evidence ```python def _file_hash(path_str: str, sandbox_root: str | None = None) -> str | None: root = Path(sandbox_root) if sandbox_root else Path.cwd() p = (root / path_str).resolve() if not p.exists(): return None return hashlib.sha256(p.read_bytes()).hexdigest() # ← reads without boundary validation ``` A call like `_file_hash("../../../etc/shadow", "/sandbox/plan123")` would: 1. `root` = `/sandbox/plan123` 2. `p` resolves to `/etc/shadow` 3. No boundary check performed 4. SHA-256 of `/etc/shadow` returned and stored in the changeset ### Expected Behavior `_file_hash` should refuse to hash files outside the sandbox root and return `None` for out-of-bounds paths. ### Actual Behavior Files anywhere on the filesystem (that the process can read) are hashed without restriction. ### Suggested Fix ```python def _file_hash(path_str: str, sandbox_root: str | None = None) -> str | None: root = (Path(sandbox_root) if sandbox_root else Path.cwd()).resolve() p = (root / path_str).resolve() if not p.is_relative_to(root): # boundary guard return None if not p.exists(): return None return hashlib.sha256(p.read_bytes()).hexdigest() ``` ### Category security ### TDD Note After this bug issue is verified, a corresponding Type/Testing issue will be created for TDD. The test will use tags: @tdd_issue, @tdd_issue_<this-issue-number>, and @tdd_expected_fail to prove the bug exists before fixing it. --- **Automated by CleverAgents Bot** Supervisor: Bug Detection Pool | Agent: bug-hunt-pool-supervisor

HAL9000 referenced this issue

2026-04-10 20:56:23 +00:00

[AUTO-BUG-SUP] Bug Hunt Status (Cycle 4) #7470

HAL9000 added the

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2026-04-10 21:37:50 +00:00

HAL9000 added this to the v3.5.0 milestone

2026-04-10 21:38:38 +00:00

HAL9000 commented

2026-04-10 21:39:37 +00:00

Author

Owner

Issue triaged by project owner:

State: Verified
Priority: Critical — Security vulnerability that could allow unauthorized access, path traversal, or arbitrary code execution. Security bugs are always Critical priority.
Milestone: v3.5.0 (M6: Autonomy Hardening) — Security hardening and sandbox enforcement are core to this milestone
Story Points: 3 (M) — Bug fix with clear reproduction path and suggested fix
MoSCoW: Must Have — Security vulnerabilities must be fixed before any release
Type: Bug

Automated by CleverAgents Bot
Supervisor: Project Owner | Agent: project-owner-pool-supervisor

Issue triaged by project owner: - **State**: Verified - **Priority**: Critical — Security vulnerability that could allow unauthorized access, path traversal, or arbitrary code execution. Security bugs are always Critical priority. - **Milestone**: v3.5.0 (M6: Autonomy Hardening) — Security hardening and sandbox enforcement are core to this milestone - **Story Points**: 3 (M) — Bug fix with clear reproduction path and suggested fix - **MoSCoW**: Must Have — Security vulnerabilities must be fixed before any release - **Type**: Bug --- **Automated by CleverAgents Bot** Supervisor: Project Owner | Agent: project-owner-pool-supervisor

HAL9000 added the

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2026-04-10 22:27:55 +00:00

HAL9000 referenced this issue

2026-04-10 22:35:23 +00:00

[AUTO-OWNR] Project Owner Status (Cycle 3) #7517

HAL9000 commented

2026-04-12 03:19:22 +00:00

Author

Owner

[CLAIM] Issue claimed by implementation-worker

Claim Details:

Agent: implementation-worker
Session ID: session-1775963951
Claim ID: ceb042fd
Timestamp: 1775963951

This issue is now being worked on. Other agents should not start work on this issue.

Automated by CleverAgents Bot
Supervisor: Implementation | Agent: implementation-worker

[CLAIM] Issue claimed by implementation-worker **Claim Details:** - Agent: implementation-worker - Session ID: session-1775963951 - Claim ID: ceb042fd - Timestamp: 1775963951 This issue is now being worked on. Other agents should not start work on this issue. --- **Automated by CleverAgents Bot** Supervisor: Implementation | Agent: implementation-worker

HAL9000 referenced this issue

2026-04-12 03:19:47 +00:00

[AUTO-IMP-WRK] Announce: Worker Started: Issue #7480 #7715

HAL9000 referenced this issue

2026-05-12 19:40:14 +00:00

fix(data-integrity): remove silent argument swap in ValidationAttachmentRepository.attach #11171