feat(MAT-107): memory encryption & user isolation

- Per-user Fernet encryption for fact/chunk_text/summary fields
- Postgres RLS with memory_app restricted role
- SSL for memory-db connections
- Data migration script (migrate_encrypt.py)
- DB migration (migrate_rls.sql)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

memory-service/Dockerfile

@@ -2,5 +2,5 @@ FROM python:3.11-slim
 WORKDIR /app
 COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
-COPY main.py .
+COPY main.py migrate_encrypt.py ./
 CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8090"]

memory-service/main.py

@@ -1,9 +1,12 @@
 import os
 import logging
 import time
+import hashlib
+import base64
 
 import asyncpg
 import httpx
+from cryptography.fernet import Fernet
 from fastapi import FastAPI, HTTPException
 from pydantic import BaseModel
 
@@ -11,14 +14,49 @@ logger = logging.getLogger("memory-service")
 logging.basicConfig(level=logging.INFO)
 
 DB_DSN = os.environ.get("DATABASE_URL", "postgresql://memory:memory@memory-db:5432/memories")
+OWNER_DSN = os.environ.get("OWNER_DATABASE_URL", "postgresql://memory:{pw}@memory-db:5432/memories".format(
+    pw=os.environ.get("MEMORY_DB_OWNER_PASSWORD", "memory")
+))
 LITELLM_URL = os.environ.get("LITELLM_BASE_URL", "")
 LITELLM_KEY = os.environ.get("LITELLM_API_KEY", "not-needed")
 EMBED_MODEL = os.environ.get("EMBED_MODEL", "text-embedding-3-small")
 EMBED_DIMS = int(os.environ.get("EMBED_DIMS", "1536"))
 DEDUP_THRESHOLD = float(os.environ.get("DEDUP_THRESHOLD", "0.92"))
+ENCRYPTION_KEY = os.environ.get("MEMORY_ENCRYPTION_KEY", "")
 
 app = FastAPI(title="Memory Service")
 pool: asyncpg.Pool | None = None
+owner_pool: asyncpg.Pool | None = None
+
+
+def _derive_user_key(user_id: str) -> bytes:
+    """Derive a per-user Fernet key from master key + user_id via HMAC-SHA256."""
+    if not ENCRYPTION_KEY:
+        raise RuntimeError("MEMORY_ENCRYPTION_KEY not set")
+    derived = hashlib.pbkdf2_hmac(
+        "sha256", ENCRYPTION_KEY.encode(), user_id.encode(), iterations=1
+    )
+    return base64.urlsafe_b64encode(derived)
+
+
+def _encrypt(text: str, user_id: str) -> str:
+    """Encrypt text with per-user Fernet key. Returns base64 ciphertext."""
+    if not ENCRYPTION_KEY:
+        return text
+    f = Fernet(_derive_user_key(user_id))
+    return f.encrypt(text.encode()).decode()
+
+
+def _decrypt(ciphertext: str, user_id: str) -> str:
+    """Decrypt ciphertext with per-user Fernet key."""
+    if not ENCRYPTION_KEY:
+        return ciphertext
+    try:
+        f = Fernet(_derive_user_key(user_id))
+        return f.decrypt(ciphertext.encode()).decode()
+    except Exception:
+        # Plaintext fallback for not-yet-migrated rows
+        return ciphertext
 
 
 class StoreRequest(BaseModel):
@@ -78,11 +116,18 @@ async def _embed_batch(texts: list[str]) -> list[list[float]]:
         return [item["embedding"] for item in sorted(data, key=lambda x: x["index"])]
 
 
+async def _set_rls_user(conn, user_id: str):
+    """Set the RLS session variable for the current connection."""
+    await conn.execute("SELECT set_config('app.current_user_id', $1, false)", user_id)
+
+
 async def _init_db():
     """Create pgvector extension and memories table if not exists."""
     global pool
-    pool = await asyncpg.create_pool(DB_DSN, min_size=2, max_size=10)
-    async with pool.acquire() as conn:
+    # Use owner connection for DDL (CREATE TABLE/INDEX), then create restricted pool
+    owner_conn = await asyncpg.connect(OWNER_DSN)
+    conn = owner_conn
+    try:
         await conn.execute("CREATE EXTENSION IF NOT EXISTS vector")
         await conn.execute(f"""
             CREATE TABLE IF NOT EXISTS memories (
@@ -121,7 +166,14 @@ async def _init_db():
         await conn.execute("""
             CREATE INDEX IF NOT EXISTS idx_chunks_room_id ON conversation_chunks (room_id)
         """)
-    logger.info("Database initialized (dims=%d)", EMBED_DIMS)
+    finally:
+        await owner_conn.close()
+    # Create restricted pool for all request handlers (RLS applies)
+    pool = await asyncpg.create_pool(DB_DSN, min_size=2, max_size=10)
+    # Owner pool for admin queries (bypasses RLS) — 1 connection only
+    global owner_pool
+    owner_pool = await asyncpg.create_pool(OWNER_DSN, min_size=1, max_size=2)
+    logger.info("Database initialized (dims=%d, encryption=%s)", EMBED_DIMS, "ON" if ENCRYPTION_KEY else "OFF")
 
 
 @app.on_event("startup")
@@ -133,21 +185,28 @@ async def startup():
 async def shutdown():
     if pool:
         await pool.close()
+    if owner_pool:
+        await owner_pool.close()
 
 
 @app.get("/health")
 async def health():
-    if pool:
-        async with pool.acquire() as conn:
+    if owner_pool:
+        async with owner_pool.acquire() as conn:
             mem_count = await conn.fetchval("SELECT count(*) FROM memories")
             chunk_count = await conn.fetchval("SELECT count(*) FROM conversation_chunks")
-        return {"status": "ok", "total_memories": mem_count, "total_chunks": chunk_count}
+        return {
+            "status": "ok",
+            "total_memories": mem_count,
+            "total_chunks": chunk_count,
+            "encryption": "on" if ENCRYPTION_KEY else "off",
+        }
     return {"status": "no_db"}
 
 
 @app.post("/memories/store")
 async def store_memory(req: StoreRequest):
-    """Embed fact, deduplicate by cosine similarity, insert."""
+    """Embed fact, deduplicate by cosine similarity, insert encrypted."""
     if not req.fact.strip():
         raise HTTPException(400, "Empty fact")
 
@@ -155,6 +214,8 @@ async def store_memory(req: StoreRequest):
     vec_literal = "[" + ",".join(str(v) for v in embedding) + "]"
 
     async with pool.acquire() as conn:
+        await _set_rls_user(conn, req.user_id)
+
         # Check for duplicates (cosine similarity > threshold)
         dup = await conn.fetchval(
             """
@@ -169,12 +230,13 @@ async def store_memory(req: StoreRequest):
             logger.info("Duplicate memory for %s (similar to id=%d), skipping", req.user_id, dup)
             return {"stored": False, "reason": "duplicate"}
 
+        encrypted_fact = _encrypt(req.fact.strip(), req.user_id)
         await conn.execute(
             """
             INSERT INTO memories (user_id, fact, source_room, created_at, embedding)
             VALUES ($1, $2, $3, $4, $5::vector)
             """,
-            req.user_id, req.fact.strip(), req.source_room, time.time(), vec_literal,
+            req.user_id, encrypted_fact, req.source_room, time.time(), vec_literal,
         )
     logger.info("Stored memory for %s: %s", req.user_id, req.fact[:60])
     return {"stored": True}
@@ -187,6 +249,8 @@ async def query_memories(req: QueryRequest):
     vec_literal = "[" + ",".join(str(v) for v in embedding) + "]"
 
     async with pool.acquire() as conn:
+        await _set_rls_user(conn, req.user_id)
+
         rows = await conn.fetch(
             """
             SELECT fact, source_room, created_at,
@@ -201,7 +265,7 @@ async def query_memories(req: QueryRequest):
 
     results = [
         {
-            "fact": r["fact"],
+            "fact": _decrypt(r["fact"], req.user_id),
             "source_room": r["source_room"],
             "created_at": r["created_at"],
             "similarity": float(r["similarity"]),
@@ -215,6 +279,7 @@ async def query_memories(req: QueryRequest):
 async def delete_user_memories(user_id: str):
     """GDPR delete — remove all memories for a user."""
     async with pool.acquire() as conn:
+        await _set_rls_user(conn, user_id)
         result = await conn.execute("DELETE FROM memories WHERE user_id = $1", user_id)
     count = int(result.split()[-1])
     logger.info("Deleted %d memories for %s", count, user_id)
@@ -225,6 +290,7 @@ async def delete_user_memories(user_id: str):
 async def list_user_memories(user_id: str):
     """List all memories for a user (for UI/debug)."""
     async with pool.acquire() as conn:
+        await _set_rls_user(conn, user_id)
         rows = await conn.fetch(
             """
             SELECT fact, source_room, created_at
@@ -238,7 +304,7 @@ async def list_user_memories(user_id: str):
         "user_id": user_id,
         "count": len(rows),
         "memories": [
-            {"fact": r["fact"], "source_room": r["source_room"], "created_at": r["created_at"]}
+            {"fact": _decrypt(r["fact"], user_id), "source_room": r["source_room"], "created_at": r["created_at"]}
             for r in rows
         ],
     }
@@ -249,7 +315,7 @@ async def list_user_memories(user_id: str):
 
 @app.post("/chunks/store")
 async def store_chunk(req: ChunkStoreRequest):
-    """Store a conversation chunk with its summary embedding."""
+    """Store a conversation chunk with its summary embedding, encrypted."""
     if not req.summary.strip():
         raise HTTPException(400, "Empty summary")
 
@@ -257,14 +323,18 @@ async def store_chunk(req: ChunkStoreRequest):
     vec_literal = "[" + ",".join(str(v) for v in embedding) + "]"
     ts = req.original_ts or time.time()
 
+    encrypted_text = _encrypt(req.chunk_text, req.user_id)
+    encrypted_summary = _encrypt(req.summary, req.user_id)
+
     async with pool.acquire() as conn:
+        await _set_rls_user(conn, req.user_id)
         await conn.execute(
             """
             INSERT INTO conversation_chunks
                 (user_id, room_id, chunk_text, summary, source_event_id, original_ts, embedding)
             VALUES ($1, $2, $3, $4, $5, $6, $7::vector)
             """,
-            req.user_id, req.room_id, req.chunk_text, req.summary,
+            req.user_id, req.room_id, encrypted_text, encrypted_summary,
             req.source_event_id, ts, vec_literal,
         )
     logger.info("Stored chunk for %s in %s: %s", req.user_id, req.room_id, req.summary[:60])
@@ -294,7 +364,13 @@ async def query_chunks(req: ChunkQueryRequest):
     where = f"WHERE {' AND '.join(conditions)}" if conditions else ""
     params.append(req.top_k)
 
+    # Determine user_id for RLS and decryption
+    rls_user = req.user_id if req.user_id else ""
+
     async with pool.acquire() as conn:
+        if rls_user:
+            await _set_rls_user(conn, rls_user)
+
         rows = await conn.fetch(
             f"""
             SELECT chunk_text, summary, room_id, user_id, original_ts, source_event_id,
@@ -309,8 +385,8 @@ async def query_chunks(req: ChunkQueryRequest):
 
     results = [
         {
-            "chunk_text": r["chunk_text"],
-            "summary": r["summary"],
+            "chunk_text": _decrypt(r["chunk_text"], r["user_id"]),
+            "summary": _decrypt(r["summary"], r["user_id"]),
             "room_id": r["room_id"],
             "user_id": r["user_id"],
             "original_ts": r["original_ts"],
@@ -343,15 +419,18 @@ async def bulk_store_chunks(req: ChunkBulkStoreRequest):
 
         async with pool.acquire() as conn:
             for chunk, embedding in zip(batch, embeddings):
+                await _set_rls_user(conn, chunk.user_id)
                 vec_literal = "[" + ",".join(str(v) for v in embedding) + "]"
                 ts = chunk.original_ts or time.time()
+                encrypted_text = _encrypt(chunk.chunk_text, chunk.user_id)
+                encrypted_summary = _encrypt(chunk.summary, chunk.user_id)
                 await conn.execute(
                     """
                     INSERT INTO conversation_chunks
                         (user_id, room_id, chunk_text, summary, source_event_id, original_ts, embedding)
                     VALUES ($1, $2, $3, $4, $5, $6, $7::vector)
                     """,
-                    chunk.user_id, chunk.room_id, chunk.chunk_text, chunk.summary,
+                    chunk.user_id, chunk.room_id, encrypted_text, encrypted_summary,
                     chunk.source_event_id, ts, vec_literal,
                 )
                 stored += 1
@@ -364,6 +443,7 @@ async def bulk_store_chunks(req: ChunkBulkStoreRequest):
 async def count_user_chunks(user_id: str):
     """Count conversation chunks for a user."""
     async with pool.acquire() as conn:
+        await _set_rls_user(conn, user_id)
         count = await conn.fetchval(
             "SELECT count(*) FROM conversation_chunks WHERE user_id = $1", user_id,
         )

memory-service/migrate_encrypt.py

@@ -0,0 +1,95 @@
+#!/usr/bin/env python3
+"""MAT-107: One-time migration to encrypt existing plaintext memory data.
+
+Run INSIDE the memory-service container after deploying new code:
+    docker exec -it matrix-ai-agent-memory-service-1 python migrate_encrypt.py
+
+Connects as owner (memory) to bypass RLS.
+"""
+import os
+import sys
+import hashlib
+import base64
+import asyncio
+
+import asyncpg
+from cryptography.fernet import Fernet, InvalidToken
+
+OWNER_DSN = os.environ.get(
+    "OWNER_DATABASE_URL",
+    "postgresql://memory:{password}@memory-db:5432/memories".format(
+        password=os.environ.get("MEMORY_DB_OWNER_PASSWORD", "memory")
+    ),
+)
+ENCRYPTION_KEY = os.environ.get("MEMORY_ENCRYPTION_KEY", "")
+
+
+def _derive_user_key(user_id: str) -> bytes:
+    derived = hashlib.pbkdf2_hmac("sha256", ENCRYPTION_KEY.encode(), user_id.encode(), iterations=1)
+    return base64.urlsafe_b64encode(derived)
+
+
+def _encrypt(text: str, user_id: str) -> str:
+    f = Fernet(_derive_user_key(user_id))
+    return f.encrypt(text.encode()).decode()
+
+
+def _is_encrypted(text: str, user_id: str) -> bool:
+    """Check if text is already Fernet-encrypted."""
+    try:
+        f = Fernet(_derive_user_key(user_id))
+        f.decrypt(text.encode())
+        return True
+    except (InvalidToken, Exception):
+        return False
+
+
+async def migrate():
+    if not ENCRYPTION_KEY:
+        print("ERROR: MEMORY_ENCRYPTION_KEY not set")
+        sys.exit(1)
+
+    conn = await asyncpg.connect(OWNER_DSN)
+
+    # Migrate memories
+    rows = await conn.fetch("SELECT id, user_id, fact FROM memories ORDER BY id")
+    print(f"Migrating {len(rows)} memories...")
+    encrypted = 0
+    skipped = 0
+    for row in rows:
+        if _is_encrypted(row["fact"], row["user_id"]):
+            skipped += 1
+            continue
+        enc_fact = _encrypt(row["fact"], row["user_id"])
+        await conn.execute("UPDATE memories SET fact = $1 WHERE id = $2", enc_fact, row["id"])
+        encrypted += 1
+        if encrypted % 100 == 0:
+            print(f"  memories: {encrypted}/{len(rows)} encrypted")
+    print(f"Memories done: {encrypted} encrypted, {skipped} already encrypted")
+
+    # Migrate conversation_chunks
+    rows = await conn.fetch("SELECT id, user_id, chunk_text, summary FROM conversation_chunks ORDER BY id")
+    print(f"Migrating {len(rows)} chunks...")
+    encrypted = 0
+    skipped = 0
+    for row in rows:
+        if _is_encrypted(row["chunk_text"], row["user_id"]):
+            skipped += 1
+            continue
+        enc_text = _encrypt(row["chunk_text"], row["user_id"])
+        enc_summary = _encrypt(row["summary"], row["user_id"])
+        await conn.execute(
+            "UPDATE conversation_chunks SET chunk_text = $1, summary = $2 WHERE id = $3",
+            enc_text, enc_summary, row["id"],
+        )
+        encrypted += 1
+        if encrypted % 500 == 0:
+            print(f"  chunks: {encrypted}/{len(rows)} encrypted")
+    print(f"Chunks done: {encrypted} encrypted, {skipped} already encrypted")
+
+    await conn.close()
+    print("Migration complete.")
+
+
+if __name__ == "__main__":
+    asyncio.run(migrate())

memory-service/requirements.txt

@@ -3,3 +3,4 @@ uvicorn>=0.34,<1.0
 asyncpg>=0.30,<1.0
 pgvector>=0.3,<1.0
 httpx>=0.27,<1.0
+cryptography>=44.0,<45.0