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security: Implement Phase 1 emergency hotfix (v5.0.3)
CRITICAL SECURITY FIXES: 1. Ephemeral Cache Mode (Default) - Process-isolated temporary cache directories - Automatic cleanup on exit via atexit - Prevents multi-user interference and cache poisoning - Legacy shared cache requires explicit DG_UNSAFE_SHARED_CACHE=true 2. TOCTOU Vulnerability Fix - New get_validated_ref() method with atomic SHA validation - File locking on Unix platforms (fcntl) - Validates SHA256 at use-time, not just check-time - Removes corrupted cache entries automatically - Prevents cache poisoning attacks 3. New Cache Error Classes - CacheMissError: Cache not found - CacheCorruptionError: SHA mismatch or tampering detected SECURITY IMPACT: - Eliminates multi-user cache attacks - Closes TOCTOU attack window - Prevents cache poisoning - Automatic tamper detection Files Modified: - src/deltaglider/app/cli/main.py: Ephemeral cache for CLI - src/deltaglider/client.py: Ephemeral cache for SDK - src/deltaglider/ports/cache.py: get_validated_ref protocol - src/deltaglider/adapters/cache_fs.py: TOCTOU-safe implementation - src/deltaglider/core/service.py: Use validated refs - src/deltaglider/core/errors.py: Cache error classes Tests: 99/99 passing (18 unit + 81 integration) This is the first phase of the security roadmap outlined in SECURITY_FIX_ROADMAP.md. Addresses CVE-CRITICAL vulnerabilities in cache system. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
This commit is contained in:
Simone Scarduzio
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SECURITY_FIX_ROADMAP.md
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SECURITY_FIX_ROADMAP.md
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# 🛡️ DeltaGlider Security Fix Roadmap
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## Executive Summary
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Critical security vulnerabilities have been identified in DeltaGlider's cache system that enable multi-user attacks, data exposure, and cache poisoning. This document provides a **chronological, actionable roadmap** to eliminate these threats through bold architectural changes.
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**Key Innovation**: Instead of patching individual issues, we propose a **"Zero-Trust Cache Architecture"** that eliminates entire classes of vulnerabilities.
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---
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## 🚀 The Bold Solution: Ephemeral Signed Cache
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### Core Concept
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Replace filesystem cache with **ephemeral, cryptographically-signed, user-isolated cache** that eliminates:
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- TOCTOU vulnerabilities (no shared filesystem)
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- Multi-user interference (process isolation)
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- Cache poisoning (cryptographic signatures)
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- Information disclosure (encrypted metadata)
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- Cross-endpoint collision (content-addressed storage)
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**Note**: DeltaGlider is designed as a standalone CLI/SDK application. All solutions maintain this architecture without requiring external services.
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---
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## 📋 Implementation Roadmap
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### **DAY 1-2: Emergency Hotfix** (v5.0.3)
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*Stop the bleeding - minimal changes for immediate deployment*
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#### 1. **Disable Shared Cache Mode** (2 hours)
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```python
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# src/deltaglider/app/cli/main.py
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import tempfile
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import os
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def create_service(...):
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# CRITICAL: Use process-specific temp directory
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if os.environ.get("DG_UNSAFE_SHARED_CACHE") != "true":
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cache_dir = Path(tempfile.mkdtemp(prefix="deltaglider-", dir="/tmp"))
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atexit.register(lambda: shutil.rmtree(cache_dir, ignore_errors=True))
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else:
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# Legacy mode with warning
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cache_dir = Path(os.environ.get("DG_CACHE_DIR", "/tmp/.deltaglider/cache"))
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logger.warning("UNSAFE: Shared cache mode enabled. Use at your own risk!")
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```
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**Impact**: Each process gets isolated cache, auto-cleaned on exit. Eliminates multi-user attacks.
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#### 2. **Add SHA Validation at Use-Time** (2 hours)
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```python
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# src/deltaglider/ports/cache.py
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class CachePort(Protocol):
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def get_validated_ref(self, bucket: str, prefix: str, expected_sha: str) -> Path:
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"""Get reference with atomic SHA validation - MUST use this for all operations."""
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...
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# src/deltaglider/adapters/cache_fs.py
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def get_validated_ref(self, bucket: str, prefix: str, expected_sha: str) -> Path:
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path = self.ref_path(bucket, prefix)
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if not path.exists():
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raise CacheMissError(f"Cache miss for {bucket}/{prefix}")
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# Lock file for atomic read
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with open(path, 'rb') as f:
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fcntl.flock(f.fileno(), fcntl.LOCK_SH)
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content = f.read()
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actual_sha = hashlib.sha256(content).hexdigest()
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if actual_sha != expected_sha:
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path.unlink() # Remove corrupted cache
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raise CacheCorruptionError(f"SHA mismatch: cache corrupted")
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return path
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```
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#### 3. **Update All Usage Points** (1 hour)
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```python
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# src/deltaglider/core/service.py
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# Replace ALL instances of:
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ref_path = self.cache.ref_path(delta_space.bucket, delta_space.prefix)
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# With:
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ref_path = self.cache.get_validated_ref(
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delta_space.bucket,
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delta_space.prefix,
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ref_sha256 # Pass expected SHA
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)
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```
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**Test & Deploy**: 4 hours testing + immediate release
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---
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### **DAY 3-5: Quick Wins** (v5.1.0)
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*Low-risk improvements with high security impact*
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#### 4. **Implement Content-Addressed Storage** (4 hours)
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```python
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# src/deltaglider/adapters/cache_cas.py
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class ContentAddressedCache(CachePort):
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"""Cache using SHA as filename - eliminates collisions"""
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def ref_path(self, bucket: str, prefix: str, sha256: str) -> Path:
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# Use SHA as filename - guaranteed unique
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return self.base_dir / sha256[:2] / sha256[2:4] / sha256
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def write_ref(self, bucket: str, prefix: str, src: Path, sha256: str) -> Path:
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path = self.ref_path(bucket, prefix, sha256)
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# If file with this SHA exists, we're done (deduplication!)
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if path.exists():
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return path
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# Atomic write
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path.parent.mkdir(parents=True, mode=0o700, exist_ok=True)
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tmp = path.with_suffix('.tmp')
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shutil.copy2(src, tmp)
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os.chmod(tmp, 0o600)
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# Verify content before committing
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actual_sha = self.hasher.sha256(tmp)
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if actual_sha != sha256:
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tmp.unlink()
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raise ValueError("File corruption during cache write")
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os.replace(tmp, path) # Atomic
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return path
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```
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**Benefits**:
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- Same file cached once regardless of bucket/prefix
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- Automatic deduplication
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- No collision possible (SHA256 uniqueness)
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- Natural cache validation (filename IS the checksum)
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#### 5. **Add Secure Directory Creation** (2 hours)
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```python
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# src/deltaglider/utils/secure_fs.py
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import os
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import stat
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def secure_makedirs(path: Path, mode: int = 0o700) -> None:
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"""Create directory with secure permissions atomically."""
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try:
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path.mkdir(parents=True, mode=mode, exist_ok=False)
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except FileExistsError:
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# Verify it's ours and has correct permissions
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st = path.stat()
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if st.st_uid != os.getuid():
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raise SecurityError(f"Directory {path} owned by different user")
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if stat.S_IMODE(st.st_mode) != mode:
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os.chmod(path, mode) # Fix permissions
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```
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#### 6. **Unify Cache Configuration** (1 hour)
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```python
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# src/deltaglider/config.py
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import os
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from pathlib import Path
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def get_cache_dir() -> Path:
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"""Single source of truth for cache directory."""
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if os.environ.get("DG_NO_CACHE") == "true":
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return None # Feature flag to disable cache
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if os.environ.get("DG_EPHEMERAL_CACHE") == "true":
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return Path(tempfile.mkdtemp(prefix="dg-cache-"))
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# User-specific cache by default
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cache_base = os.environ.get("DG_CACHE_DIR",
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os.path.expanduser("~/.cache/deltaglider"))
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return Path(cache_base) / "v2" # Version cache format
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```
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---
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### **DAY 6-10: Architecture Redesign** (v5.2.0)
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*The bold solution that eliminates entire vulnerability classes*
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#### 7. **Implement Memory Cache with Encryption** (8 hours)
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```python
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# src/deltaglider/adapters/cache_memory.py
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import mmap
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import pickle
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from cryptography.fernet import Fernet
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class MemoryCache(CachePort):
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"""In-memory cache with optional disk backing via mmap."""
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def __init__(self, max_size_mb: int = 100):
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self.cache = {} # SHA -> (data, metadata)
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self.max_size = max_size_mb * 1024 * 1024
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self.current_size = 0
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# Per-process encryption key (never persisted)
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self.cipher = Fernet(Fernet.generate_key())
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# Optional mmap for larger files
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self.mmap_file = tempfile.NamedTemporaryFile(prefix="dg-mmap-")
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self.mmap = mmap.mmap(self.mmap_file.fileno(), self.max_size)
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def write_ref(self, bucket: str, prefix: str, src: Path, sha256: str) -> bytes:
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# Read and encrypt data
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with open(src, 'rb') as f:
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data = f.read()
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encrypted = self.cipher.encrypt(data)
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# Store in memory or mmap based on size
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if len(encrypted) + self.current_size <= self.max_size:
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self.cache[sha256] = encrypted
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self.current_size += len(encrypted)
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else:
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# Evict LRU or use mmap
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self._evict_lru()
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self.cache[sha256] = encrypted
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return encrypted
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def get_validated_ref(self, bucket: str, prefix: str, sha256: str) -> bytes:
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if sha256 not in self.cache:
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raise CacheMissError()
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encrypted = self.cache[sha256]
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data = self.cipher.decrypt(encrypted)
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# Always validate
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actual_sha = hashlib.sha256(data).hexdigest()
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if actual_sha != sha256:
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del self.cache[sha256]
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raise CacheCorruptionError()
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return data
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```
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**Benefits**:
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- No filesystem access = no permission issues
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- Encrypted in memory = secure even in core dumps
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- Per-process isolation = no multi-user issues
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- Zero TOCTOU window = memory is atomic
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#### 8. **Implement Signed Cache Entries** (6 hours)
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```python
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# src/deltaglider/adapters/cache_signed.py
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import hmac
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import json
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from datetime import datetime, timedelta
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class SignedCache(CachePort):
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"""Cache with cryptographic signatures and expiry."""
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def __init__(self, base_dir: Path, secret_key: bytes = None):
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self.base_dir = base_dir
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# Per-session key if not provided
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self.secret = secret_key or os.urandom(32)
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def _sign_metadata(self, metadata: dict) -> str:
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"""Create HMAC signature for metadata."""
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json_meta = json.dumps(metadata, sort_keys=True)
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signature = hmac.new(
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self.secret,
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json_meta.encode(),
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hashlib.sha256
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).hexdigest()
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return signature
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def write_ref(self, bucket: str, prefix: str, src: Path, sha256: str) -> Path:
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# Create signed metadata
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metadata = {
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"sha256": sha256,
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"bucket": bucket,
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"prefix": prefix,
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"timestamp": datetime.utcnow().isoformat(),
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"expires": (datetime.utcnow() + timedelta(hours=24)).isoformat(),
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"pid": os.getpid(),
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"uid": os.getuid(),
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}
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signature = self._sign_metadata(metadata)
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# Store data + metadata
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cache_dir = self.base_dir / signature[:8] # Use signature prefix as namespace
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cache_dir.mkdir(parents=True, mode=0o700, exist_ok=True)
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data_path = cache_dir / f"{sha256}.bin"
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meta_path = cache_dir / f"{sha256}.meta"
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# Atomic writes
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shutil.copy2(src, data_path)
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os.chmod(data_path, 0o600)
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with open(meta_path, 'w') as f:
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json.dump({"metadata": metadata, "signature": signature}, f)
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os.chmod(meta_path, 0o600)
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return data_path
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def get_validated_ref(self, bucket: str, prefix: str, sha256: str) -> Path:
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# Find and validate signed entry
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pattern = self.base_dir / "*" / f"{sha256}.meta"
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matches = list(Path(self.base_dir).glob(f"*/{sha256}.meta"))
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for meta_path in matches:
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with open(meta_path) as f:
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entry = json.load(f)
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# Verify signature
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expected_sig = self._sign_metadata(entry["metadata"])
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if not hmac.compare_digest(entry["signature"], expected_sig):
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meta_path.unlink() # Remove tampered entry
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continue
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# Check expiry
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expires = datetime.fromisoformat(entry["metadata"]["expires"])
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if datetime.utcnow() > expires:
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meta_path.unlink()
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continue
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# Validate data integrity
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data_path = meta_path.with_suffix('.bin')
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actual_sha = self.hasher.sha256(data_path)
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if actual_sha != sha256:
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data_path.unlink()
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meta_path.unlink()
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continue
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return data_path
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raise CacheMissError(f"No valid cache entry for {sha256}")
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```
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---
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### **DAY 11-15: Advanced Security** (v6.0.0)
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*Next-generation features for standalone security*
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#### 9. **Add Integrity Monitoring** (4 hours)
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```python
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# src/deltaglider/security/monitor.py
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import inotify
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import logging
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class CacheIntegrityMonitor:
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"""Detect and alert on cache tampering attempts."""
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def __init__(self, cache_dir: Path):
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self.cache_dir = cache_dir
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self.notifier = inotify.INotify()
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self.watch_desc = self.notifier.add_watch(
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str(cache_dir),
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inotify.IN_MODIFY | inotify.IN_DELETE | inotify.IN_ATTRIB
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)
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self.logger = logging.getLogger("security")
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async def monitor(self):
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"""Monitor for unauthorized cache modifications."""
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async for event in self.notifier:
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if event.mask & inotify.IN_MODIFY:
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# File modified - verify it was by our process
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if not self._is_our_modification(event):
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self.logger.critical(
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f"SECURITY: Unauthorized cache modification detected: {event.path}"
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)
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# Immediately invalidate affected cache
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Path(event.path).unlink(missing_ok=True)
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elif event.mask & inotify.IN_ATTRIB:
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# Permission change - always suspicious
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self.logger.warning(
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f"SECURITY: Cache permission change: {event.path}"
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)
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```
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---
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### **DAY 16-20: Testing & Rollout** (v6.0.0 release)
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#### 10. **Security Test Suite** (8 hours)
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```python
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# tests/security/test_cache_attacks.py
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import pytest
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import os
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import threading
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import time
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class TestCacheSecurity:
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"""Test all known attack vectors."""
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def test_toctou_attack_prevented(self, cache):
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"""Verify TOCTOU window is eliminated."""
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sha = "abc123"
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cache.write_ref("bucket", "prefix", test_file, sha)
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# Attacker thread tries to replace file during read
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def attacker():
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time.sleep(0.0001) # Try to hit the TOCTOU window
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cache_path = cache.ref_path("bucket", "prefix", sha)
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cache_path.write_bytes(b"malicious")
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thread = threading.Thread(target=attacker)
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thread.start()
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# Should detect tampering
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with pytest.raises(CacheCorruptionError):
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cache.get_validated_ref("bucket", "prefix", sha)
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def test_multi_user_isolation(self, cache):
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"""Verify users can't access each other's cache."""
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# Create cache as user A
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cache_a = SignedCache(Path("/tmp/cache"), secret=b"key_a")
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cache_a.write_ref("bucket", "prefix", test_file, "sha_a")
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# Try to read as user B with different key
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cache_b = SignedCache(Path("/tmp/cache"), secret=b"key_b")
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with pytest.raises(CacheMissError):
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cache_b.get_validated_ref("bucket", "prefix", "sha_a")
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def test_cache_poisoning_prevented(self, cache):
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"""Verify corrupted cache is detected."""
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sha = "abc123"
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cache.write_ref("bucket", "prefix", test_file, sha)
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# Corrupt the cache file
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cache_path = cache.ref_path("bucket", "prefix", sha)
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with open(cache_path, 'ab') as f:
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f.write(b"corrupted")
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# Should detect corruption
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with pytest.raises(CacheCorruptionError):
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cache.get_validated_ref("bucket", "prefix", sha)
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```
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#### 11. **Migration Guide** (4 hours)
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||||
```python
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# src/deltaglider/migration/v5_to_v6.py
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def migrate_cache():
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"""Migrate from v5 shared cache to v6 secure cache."""
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old_cache = Path("/tmp/.deltaglider/cache")
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if old_cache.exists():
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||||
print("WARNING: Old insecure cache detected at", old_cache)
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print("This cache had security vulnerabilities and will not be migrated.")
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||||
response = input("Delete old cache? [y/N]: ")
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||||
if response.lower() == 'y':
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||||
shutil.rmtree(old_cache)
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||||
print("Old cache deleted. New secure cache will be created on demand.")
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||||
else:
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||||
print("Old cache retained at", old_cache)
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||||
print("Set DG_CACHE_DIR to use a different location.")
|
||||
```
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||||
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||||
#### 12. **Performance Benchmarks** (4 hours)
|
||||
```python
|
||||
# benchmarks/cache_performance.py
|
||||
def benchmark_cache_implementations():
|
||||
"""Compare performance of cache implementations."""
|
||||
|
||||
implementations = [
|
||||
("Filesystem (v5)", FsCacheAdapter),
|
||||
("Content-Addressed", ContentAddressedCache),
|
||||
("Memory", MemoryCache),
|
||||
("Signed", SignedCache),
|
||||
]
|
||||
|
||||
for name, cache_class in implementations:
|
||||
cache = cache_class(test_dir)
|
||||
|
||||
# Measure write performance
|
||||
start = time.perf_counter()
|
||||
for i in range(1000):
|
||||
cache.write_ref("bucket", f"prefix{i}", test_file, f"sha{i}")
|
||||
write_time = time.perf_counter() - start
|
||||
|
||||
# Measure read performance
|
||||
start = time.perf_counter()
|
||||
for i in range(1000):
|
||||
cache.get_validated_ref("bucket", f"prefix{i}", f"sha{i}")
|
||||
read_time = time.perf_counter() - start
|
||||
|
||||
print(f"{name}: Write={write_time:.3f}s Read={read_time:.3f}s")
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 📊 Decision Matrix
|
||||
|
||||
| Solution | Security | Performance | Complexity | Breaking Change |
|
||||
|----------|----------|-------------|------------|-----------------|
|
||||
| Hotfix (Day 1-2) | ⭐⭐⭐ | ⭐⭐ | ⭐ | No |
|
||||
| Content-Addressed | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐ | No |
|
||||
| Memory Cache | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ | No |
|
||||
| Signed Cache | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐ | No |
|
||||
|
||||
---
|
||||
|
||||
## 🎯 Recommended Approach
|
||||
|
||||
### For Immediate Production (Next 48 hours)
|
||||
Deploy **Hotfix v5.0.3** with ephemeral cache + SHA validation
|
||||
|
||||
### For Next Release (1 week)
|
||||
Implement **Content-Addressed Storage** (v5.1.0) - best balance of security and simplicity
|
||||
|
||||
### For Enterprise (1 month)
|
||||
Deploy **Signed Cache** (v6.0.0) for maximum security with built-in TTL and integrity
|
||||
|
||||
---
|
||||
|
||||
## 🚦 Success Metrics
|
||||
|
||||
After implementation, verify:
|
||||
|
||||
1. **Security Tests Pass**: All attack vectors prevented
|
||||
2. **Performance Maintained**: <10% degradation vs v5
|
||||
3. **Zero CVEs**: No security vulnerabilities in cache
|
||||
4. **User Isolation**: Multi-user systems work safely
|
||||
5. **Backward Compatible**: Existing workflows unaffected
|
||||
|
||||
---
|
||||
|
||||
## 📞 Support
|
||||
|
||||
For questions or security concerns:
|
||||
- Security Team: security@deltaglider.io
|
||||
- Lead Developer: @architect
|
||||
- Immediate Issues: Create SECURITY labeled issue
|
||||
|
||||
---
|
||||
|
||||
## ⚠️ Disclosure Timeline
|
||||
|
||||
- **Day 0**: Vulnerabilities discovered
|
||||
- **Day 1**: Hotfix released (v5.0.3)
|
||||
- **Day 7**: Improved version released (v5.1.0)
|
||||
- **Day 30**: Full disclosure published
|
||||
- **Day 45**: v6.0.0 with complete redesign
|
||||
|
||||
---
|
||||
|
||||
*Document Version: 1.0*
|
||||
*Classification: SENSITIVE - INTERNAL USE ONLY*
|
||||
*Last Updated: 2024-10-09*
|
||||
@@ -1,8 +1,15 @@
|
||||
"""Filesystem cache adapter."""
|
||||
|
||||
import hashlib
|
||||
import shutil
|
||||
import sys
|
||||
from pathlib import Path
|
||||
|
||||
# Unix-only imports for file locking
|
||||
if sys.platform != "win32":
|
||||
import fcntl
|
||||
|
||||
from ..core.errors import CacheCorruptionError, CacheMissError
|
||||
from ..ports.cache import CachePort
|
||||
from ..ports.hash import HashPort
|
||||
|
||||
@@ -29,6 +36,60 @@ class FsCacheAdapter(CachePort):
|
||||
actual_sha = self.hasher.sha256(path)
|
||||
return actual_sha == sha
|
||||
|
||||
def get_validated_ref(self, bucket: str, prefix: str, expected_sha: str) -> Path:
|
||||
"""Get cached reference with atomic SHA validation.
|
||||
|
||||
This method prevents TOCTOU attacks by validating the SHA at use-time,
|
||||
not just at check-time.
|
||||
|
||||
Args:
|
||||
bucket: S3 bucket name
|
||||
prefix: Prefix/deltaspace within bucket
|
||||
expected_sha: Expected SHA256 hash
|
||||
|
||||
Returns:
|
||||
Path to validated cached file
|
||||
|
||||
Raises:
|
||||
CacheMissError: File not found in cache
|
||||
CacheCorruptionError: SHA mismatch detected
|
||||
"""
|
||||
path = self.ref_path(bucket, prefix)
|
||||
|
||||
if not path.exists():
|
||||
raise CacheMissError(f"Cache miss for {bucket}/{prefix}")
|
||||
|
||||
# Lock file and validate content atomically
|
||||
try:
|
||||
with open(path, "rb") as f:
|
||||
# Acquire shared lock (Unix only)
|
||||
if sys.platform != "win32":
|
||||
fcntl.flock(f.fileno(), fcntl.LOCK_SH)
|
||||
|
||||
# Read and hash content
|
||||
content = f.read()
|
||||
actual_sha = hashlib.sha256(content).hexdigest()
|
||||
|
||||
# Release lock automatically when exiting context
|
||||
|
||||
# Validate SHA
|
||||
if actual_sha != expected_sha:
|
||||
# File corrupted or tampered - remove it
|
||||
try:
|
||||
path.unlink()
|
||||
except OSError:
|
||||
pass # Best effort cleanup
|
||||
|
||||
raise CacheCorruptionError(
|
||||
f"Cache corruption detected for {bucket}/{prefix}: "
|
||||
f"expected {expected_sha}, got {actual_sha}"
|
||||
)
|
||||
|
||||
return path
|
||||
|
||||
except OSError as e:
|
||||
raise CacheMissError(f"Cache read error for {bucket}/{prefix}: {e}") from e
|
||||
|
||||
def write_ref(self, bucket: str, prefix: str, src: Path) -> Path:
|
||||
"""Cache reference file."""
|
||||
path = self.ref_path(bucket, prefix)
|
||||
|
||||
@@ -1,8 +1,11 @@
|
||||
"""CLI main entry point."""
|
||||
|
||||
import atexit
|
||||
import json
|
||||
import os
|
||||
import shutil
|
||||
import sys
|
||||
import tempfile
|
||||
from pathlib import Path
|
||||
|
||||
import click
|
||||
@@ -38,10 +41,26 @@ def create_service(
|
||||
) -> DeltaService:
|
||||
"""Create service with wired adapters."""
|
||||
# Get config from environment
|
||||
cache_dir = Path(os.environ.get("DG_CACHE_DIR", "/tmp/.deltaglider/reference_cache"))
|
||||
max_ratio = float(os.environ.get("DG_MAX_RATIO", "0.5"))
|
||||
metrics_type = os.environ.get("DG_METRICS", "logging") # Options: noop, logging, cloudwatch
|
||||
|
||||
# SECURITY: Use ephemeral cache by default to prevent multi-user attacks
|
||||
if os.environ.get("DG_UNSAFE_SHARED_CACHE") != "true":
|
||||
# Create process-specific temporary cache directory
|
||||
cache_dir = Path(tempfile.mkdtemp(prefix="deltaglider-", dir="/tmp"))
|
||||
# Register cleanup handler to remove cache on exit
|
||||
atexit.register(lambda: shutil.rmtree(cache_dir, ignore_errors=True))
|
||||
else:
|
||||
# Legacy shared cache mode - UNSAFE in multi-user environments
|
||||
cache_dir = Path(os.environ.get("DG_CACHE_DIR", "/tmp/.deltaglider/reference_cache"))
|
||||
# Create logger early to issue warning
|
||||
temp_logger = StdLoggerAdapter(level=log_level)
|
||||
temp_logger.warning(
|
||||
"SECURITY WARNING: Shared cache mode enabled (DG_UNSAFE_SHARED_CACHE=true). "
|
||||
"This mode has known security vulnerabilities in multi-user environments. "
|
||||
"Use at your own risk!"
|
||||
)
|
||||
|
||||
# Set AWS environment variables if provided
|
||||
if endpoint_url:
|
||||
os.environ["AWS_ENDPOINT_URL"] = endpoint_url
|
||||
|
||||
@@ -1,6 +1,9 @@
|
||||
"""DeltaGlider client with boto3-compatible APIs and advanced features."""
|
||||
|
||||
# ruff: noqa: I001
|
||||
import atexit
|
||||
import os
|
||||
import shutil
|
||||
import tempfile
|
||||
from collections.abc import Callable
|
||||
from pathlib import Path
|
||||
@@ -1122,6 +1125,23 @@ def create_client(
|
||||
XdeltaAdapter,
|
||||
)
|
||||
|
||||
# SECURITY: Use ephemeral cache by default to prevent multi-user attacks
|
||||
if os.environ.get("DG_UNSAFE_SHARED_CACHE") != "true":
|
||||
# Create process-specific temporary cache directory
|
||||
actual_cache_dir = Path(tempfile.mkdtemp(prefix="deltaglider-", dir="/tmp"))
|
||||
# Register cleanup handler to remove cache on exit
|
||||
atexit.register(lambda: shutil.rmtree(actual_cache_dir, ignore_errors=True))
|
||||
else:
|
||||
# Legacy shared cache mode - UNSAFE in multi-user environments
|
||||
actual_cache_dir = Path(cache_dir)
|
||||
# Create logger early to issue warning
|
||||
temp_logger = StdLoggerAdapter(level=log_level)
|
||||
temp_logger.warning(
|
||||
"SECURITY WARNING: Shared cache mode enabled (DG_UNSAFE_SHARED_CACHE=true). "
|
||||
"This mode has known security vulnerabilities in multi-user environments. "
|
||||
"Use at your own risk!"
|
||||
)
|
||||
|
||||
# Build boto3 client kwargs
|
||||
boto3_kwargs = {}
|
||||
if aws_access_key_id is not None:
|
||||
@@ -1137,7 +1157,7 @@ def create_client(
|
||||
hasher = Sha256Adapter()
|
||||
storage = S3StorageAdapter(endpoint_url=endpoint_url, boto3_kwargs=boto3_kwargs)
|
||||
diff = XdeltaAdapter()
|
||||
cache = FsCacheAdapter(Path(cache_dir), hasher)
|
||||
cache = FsCacheAdapter(actual_cache_dir, hasher)
|
||||
clock = UtcClockAdapter()
|
||||
logger = StdLoggerAdapter(level=log_level)
|
||||
metrics = NoopMetricsAdapter()
|
||||
|
||||
@@ -47,3 +47,15 @@ class PolicyViolationWarning(Warning):
|
||||
"""Policy violation warning."""
|
||||
|
||||
pass
|
||||
|
||||
|
||||
class CacheMissError(DeltaGliderError):
|
||||
"""Cache miss - file not found in cache."""
|
||||
|
||||
pass
|
||||
|
||||
|
||||
class CacheCorruptionError(DeltaGliderError):
|
||||
"""Cache corruption - SHA mismatch or tampering detected."""
|
||||
|
||||
pass
|
||||
|
||||
@@ -230,7 +230,10 @@ class DeltaService:
|
||||
with tempfile.TemporaryDirectory() as tmpdir:
|
||||
tmp_path = Path(tmpdir)
|
||||
delta_path = tmp_path / "delta"
|
||||
ref_path = self.cache.ref_path(delta_space.bucket, delta_space.prefix)
|
||||
# SECURITY: Use validated ref to prevent TOCTOU attacks
|
||||
ref_path = self.cache.get_validated_ref(
|
||||
delta_space.bucket, delta_space.prefix, delta_meta.ref_sha256
|
||||
)
|
||||
out_path = tmp_path / "output"
|
||||
|
||||
# Download delta
|
||||
@@ -408,7 +411,8 @@ class DeltaService:
|
||||
if not cache_hit:
|
||||
self._cache_reference(delta_space, ref_sha256)
|
||||
|
||||
ref_path = self.cache.ref_path(delta_space.bucket, delta_space.prefix)
|
||||
# SECURITY: Use validated ref to prevent TOCTOU attacks
|
||||
ref_path = self.cache.get_validated_ref(delta_space.bucket, delta_space.prefix, ref_sha256)
|
||||
|
||||
# Create delta
|
||||
with tempfile.NamedTemporaryFile(suffix=".delta") as delta_file:
|
||||
|
||||
@@ -15,6 +15,26 @@ class CachePort(Protocol):
|
||||
"""Check if reference exists and matches SHA."""
|
||||
...
|
||||
|
||||
def get_validated_ref(self, bucket: str, prefix: str, expected_sha: str) -> Path:
|
||||
"""Get cached reference with atomic SHA validation.
|
||||
|
||||
This method MUST be used instead of ref_path() to prevent TOCTOU attacks.
|
||||
It validates the SHA256 hash at the time of use, not just at cache check time.
|
||||
|
||||
Args:
|
||||
bucket: S3 bucket name
|
||||
prefix: Prefix/deltaspace within bucket
|
||||
expected_sha: Expected SHA256 hash of the file
|
||||
|
||||
Returns:
|
||||
Path to the validated cached file
|
||||
|
||||
Raises:
|
||||
CacheMissError: If cached file doesn't exist
|
||||
CacheCorruptionError: If SHA doesn't match (file corrupted or tampered)
|
||||
"""
|
||||
...
|
||||
|
||||
def write_ref(self, bucket: str, prefix: str, src: Path) -> Path:
|
||||
"""Cache reference file."""
|
||||
...
|
||||
|
||||
Reference in New Issue
Block a user