test_security_symlink.py
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| 1 | """Phase 2.2 — Symlink attack tests. |
| 2 | |
| 3 | Covers every identified attack vector: |
| 4 | |
| 5 | 1. ``.muse/`` itself replaced by a symlink → ``find_repo_root`` rejects it. |
| 6 | 2. Critical subdirectories (``.muse/objects/``, ``.muse/commits/``, etc.) |
| 7 | replaced by symlinks → ``require_repo`` detects and exits. |
| 8 | 3. ``write_object`` / ``write_object_from_path`` detect a symlinked shard dir |
| 9 | or objects directory and raise before writing. |
| 10 | 4. ``write_text_atomic`` / ``write_shelf_entry`` detect a symlinked parent |
| 11 | directory and raise before writing. |
| 12 | 5. ``cleanup_stale_object_temps`` skips symlinked shard directories safely. |
| 13 | 6. ``_cleanup_muse_dir_temps`` skips symlinked subdirectories safely. |
| 14 | 7. Tracked-file symlinks are silently skipped by the workdir walker |
| 15 | (``os.lstat`` + ``S_ISREG`` filter). |
| 16 | 8. Stress: 50 concurrent symlink-swap attempts during an object write do not |
| 17 | corrupt or redirect any data. |
| 18 | |
| 19 | Each test creates its own isolated temporary directory — no shared state. |
| 20 | """ |
| 21 | |
| 22 | from __future__ import annotations |
| 23 | |
| 24 | import os |
| 25 | import pathlib |
| 26 | import tempfile |
| 27 | import threading |
| 28 | import time |
| 29 | from typing import TypedDict |
| 30 | |
| 31 | import pytest |
| 32 | |
| 33 | from muse.core.types import DEFAULT_HASH_ALGO, blob_id, fake_id, split_id |
| 34 | from muse.core.object_store import ( |
| 35 | cleanup_stale_object_temps, |
| 36 | objects_algo_dir, |
| 37 | write_object, |
| 38 | write_object_from_path, |
| 39 | ) |
| 40 | from muse.core.repo import _cleanup_muse_dir_temps, _verify_muse_dir_integrity, find_repo_root |
| 41 | from muse.core.io import write_text_atomic |
| 42 | from muse.core.shelf import write_shelf_entry |
| 43 | from muse.core.validation import assert_not_symlink, assert_write_inside_repo |
| 44 | from muse.core.paths import commits_dir, config_toml_path, head_path, heads_dir, muse_dir, objects_dir |
| 45 | from tests.cli_test_helper import CliRunner |
| 46 | |
| 47 | |
| 48 | # --------------------------------------------------------------------------- |
| 49 | # Helpers |
| 50 | # --------------------------------------------------------------------------- |
| 51 | |
| 52 | |
| 53 | def _make_real_repo(tmp_path: pathlib.Path) -> pathlib.Path: |
| 54 | """Initialise a minimal real (non-symlinked) ``.muse/`` repo layout.""" |
| 55 | repo = tmp_path / "repo" |
| 56 | repo.mkdir() |
| 57 | muse = muse_dir(repo) |
| 58 | for sub in ("objects", "commits", "snapshots", "refs", "refs/heads", "tags"): |
| 59 | (muse / sub).mkdir(parents=True) |
| 60 | (muse / "HEAD").write_text("ref: refs/heads/main\n") |
| 61 | (muse / "repo.json").write_text('{"repo_id": "test-repo"}') |
| 62 | return repo |
| 63 | |
| 64 | |
| 65 | |
| 66 | # --------------------------------------------------------------------------- |
| 67 | # Unit tests — assert_not_symlink / assert_write_inside_repo |
| 68 | # --------------------------------------------------------------------------- |
| 69 | |
| 70 | |
| 71 | class TestAssertNotSymlink: |
| 72 | def test_real_dir_passes(self, tmp_path: pathlib.Path) -> None: |
| 73 | real = tmp_path / "real" |
| 74 | real.mkdir() |
| 75 | assert_not_symlink(real, "real dir") # should not raise |
| 76 | |
| 77 | def test_real_file_passes(self, tmp_path: pathlib.Path) -> None: |
| 78 | f = tmp_path / "file.txt" |
| 79 | f.write_text("hello") |
| 80 | assert_not_symlink(f, "file") # should not raise |
| 81 | |
| 82 | def test_nonexistent_passes(self, tmp_path: pathlib.Path) -> None: |
| 83 | # A path that does not yet exist is not a symlink. |
| 84 | assert_not_symlink(tmp_path / "no-such-path", "ghost") |
| 85 | |
| 86 | def test_symlink_to_dir_raises(self, tmp_path: pathlib.Path) -> None: |
| 87 | target = tmp_path / "target" |
| 88 | target.mkdir() |
| 89 | link = tmp_path / "link" |
| 90 | link.symlink_to(target) |
| 91 | with pytest.raises(ValueError, match="symbolic link"): |
| 92 | assert_not_symlink(link, "test link") |
| 93 | |
| 94 | def test_symlink_to_file_raises(self, tmp_path: pathlib.Path) -> None: |
| 95 | target = tmp_path / "target.txt" |
| 96 | target.write_text("data") |
| 97 | link = tmp_path / "link.txt" |
| 98 | link.symlink_to(target) |
| 99 | with pytest.raises(ValueError, match="symbolic link"): |
| 100 | assert_not_symlink(link) |
| 101 | |
| 102 | def test_dangling_symlink_raises(self, tmp_path: pathlib.Path) -> None: |
| 103 | link = tmp_path / "dangling" |
| 104 | link.symlink_to(tmp_path / "nonexistent") |
| 105 | with pytest.raises(ValueError, match="symbolic link"): |
| 106 | assert_not_symlink(link, "dangling link") |
| 107 | |
| 108 | def test_error_message_contains_label(self, tmp_path: pathlib.Path) -> None: |
| 109 | link = tmp_path / "malicious" |
| 110 | link.symlink_to(tmp_path) |
| 111 | with pytest.raises(ValueError, match="malicious-label"): |
| 112 | assert_not_symlink(link, "malicious-label") |
| 113 | |
| 114 | |
| 115 | class TestAssertWriteInsideRepo: |
| 116 | def test_path_inside_passes(self, tmp_path: pathlib.Path) -> None: |
| 117 | repo = tmp_path / "repo" |
| 118 | repo.mkdir() |
| 119 | target = commits_dir(repo) / "abc.msgpack" |
| 120 | assert_write_inside_repo(repo, target) # should not raise |
| 121 | |
| 122 | def test_path_outside_raises(self, tmp_path: pathlib.Path) -> None: |
| 123 | repo = tmp_path / "repo" |
| 124 | repo.mkdir() |
| 125 | outside = tmp_path / "other" / "malicious.txt" |
| 126 | with pytest.raises(ValueError, match="outside the repository root"): |
| 127 | assert_write_inside_repo(repo, outside) |
| 128 | |
| 129 | def test_symlink_escaping_raises(self, tmp_path: pathlib.Path) -> None: |
| 130 | """If dest resolves outside repo via symlink, the check catches it.""" |
| 131 | repo = tmp_path / "repo" |
| 132 | repo.mkdir() |
| 133 | muse = muse_dir(repo) |
| 134 | muse.mkdir() |
| 135 | attacker = tmp_path / "attacker" |
| 136 | attacker.mkdir() |
| 137 | # Symlink .muse/objects → /tmp/attacker |
| 138 | malicious_link = muse / "objects" |
| 139 | malicious_link.symlink_to(attacker) |
| 140 | # The destination inside the objects dir resolves to attacker/... |
| 141 | # Parenthesise to avoid PosixPath * int precedence error. |
| 142 | dest = malicious_link / "ab" / ("cd" * 31) |
| 143 | with pytest.raises(ValueError, match="outside the repository root"): |
| 144 | assert_write_inside_repo(repo, dest) |
| 145 | |
| 146 | |
| 147 | # --------------------------------------------------------------------------- |
| 148 | # find_repo_root — symlinked .muse/ is rejected |
| 149 | # --------------------------------------------------------------------------- |
| 150 | |
| 151 | |
| 152 | class TestFindRepoRootSymlink: |
| 153 | def test_real_muse_dir_found(self, tmp_path: pathlib.Path) -> None: |
| 154 | repo = _make_real_repo(tmp_path) |
| 155 | found = find_repo_root(start=repo) |
| 156 | assert found == repo |
| 157 | |
| 158 | def test_symlinked_muse_dir_not_found(self, tmp_path: pathlib.Path) -> None: |
| 159 | """If .muse/ is a symlink, find_repo_root must not return that directory.""" |
| 160 | real_muse = tmp_path / "real_muse_dir" |
| 161 | real_muse.mkdir() |
| 162 | repo = tmp_path / "repo" |
| 163 | repo.mkdir() |
| 164 | muse_dir(repo).symlink_to(real_muse) |
| 165 | result = find_repo_root(start=repo) |
| 166 | assert result is None, ( |
| 167 | f"find_repo_root should return None for symlinked .muse/, got {result}" |
| 168 | ) |
| 169 | |
| 170 | def test_dangling_symlink_muse_dir_not_found(self, tmp_path: pathlib.Path) -> None: |
| 171 | repo = tmp_path / "repo" |
| 172 | repo.mkdir() |
| 173 | muse_dir(repo).symlink_to(tmp_path / "nonexistent") |
| 174 | assert find_repo_root(start=repo) is None |
| 175 | |
| 176 | def test_symlink_to_symlink_muse_dir_rejected(self, tmp_path: pathlib.Path) -> None: |
| 177 | real_muse = tmp_path / "real_muse" |
| 178 | real_muse.mkdir() |
| 179 | intermediate = tmp_path / "intermediate" |
| 180 | intermediate.symlink_to(real_muse) |
| 181 | repo = tmp_path / "repo" |
| 182 | repo.mkdir() |
| 183 | muse_dir(repo).symlink_to(intermediate) |
| 184 | assert find_repo_root(start=repo) is None |
| 185 | |
| 186 | def test_env_override_still_requires_real_muse(self, tmp_path: pathlib.Path, monkeypatch: pytest.MonkeyPatch) -> None: |
| 187 | """MUSE_REPO_ROOT override: returns None if .muse/ is a symlink.""" |
| 188 | real_muse = tmp_path / "real_muse" |
| 189 | real_muse.mkdir() |
| 190 | repo = tmp_path / "repo" |
| 191 | repo.mkdir() |
| 192 | muse_dir(repo).symlink_to(real_muse) |
| 193 | monkeypatch.setenv("MUSE_REPO_ROOT", str(repo)) |
| 194 | result = find_repo_root() |
| 195 | assert result is None |
| 196 | |
| 197 | |
| 198 | # --------------------------------------------------------------------------- |
| 199 | # _verify_muse_dir_integrity — critical subdirs must not be symlinks |
| 200 | # --------------------------------------------------------------------------- |
| 201 | |
| 202 | |
| 203 | class TestVerifyMuseDirIntegrity: |
| 204 | def test_clean_repo_passes(self, tmp_path: pathlib.Path) -> None: |
| 205 | repo = _make_real_repo(tmp_path) |
| 206 | _verify_muse_dir_integrity(muse_dir(repo)) # must not raise |
| 207 | |
| 208 | @pytest.mark.parametrize("subdir", [ |
| 209 | "objects", |
| 210 | "refs", |
| 211 | "refs/heads", |
| 212 | "tags", |
| 213 | ]) |
| 214 | def test_symlinked_subdir_causes_exit( |
| 215 | self, tmp_path: pathlib.Path, subdir: str |
| 216 | ) -> None: |
| 217 | import shutil |
| 218 | repo = _make_real_repo(tmp_path) |
| 219 | muse = muse_dir(repo) |
| 220 | attacker = tmp_path / "attacker" |
| 221 | attacker.mkdir(parents=True, exist_ok=True) |
| 222 | target = muse / subdir |
| 223 | # Remove the real directory tree (may be non-empty, e.g. refs/). |
| 224 | if target.exists() and not target.is_symlink(): |
| 225 | shutil.rmtree(target) |
| 226 | target.symlink_to(attacker) |
| 227 | with pytest.raises(SystemExit): |
| 228 | _verify_muse_dir_integrity(muse) |
| 229 | |
| 230 | def test_missing_subdirs_pass(self, tmp_path: pathlib.Path) -> None: |
| 231 | """Newly-initialised repos may not have all dirs yet — that's fine.""" |
| 232 | repo = tmp_path / "fresh" |
| 233 | repo.mkdir() |
| 234 | muse = muse_dir(repo) |
| 235 | muse.mkdir() |
| 236 | _verify_muse_dir_integrity(muse) # no dirs present yet — must not raise |
| 237 | |
| 238 | |
| 239 | # --------------------------------------------------------------------------- |
| 240 | # write_object — symlinked shard directory is rejected |
| 241 | # --------------------------------------------------------------------------- |
| 242 | |
| 243 | |
| 244 | class TestWriteObjectSymlink: |
| 245 | def test_normal_write_succeeds(self, tmp_path: pathlib.Path) -> None: |
| 246 | repo = _make_real_repo(tmp_path) |
| 247 | content = b"hello world" |
| 248 | oid = blob_id(content) |
| 249 | result = write_object(repo, oid, content) |
| 250 | assert result is True |
| 251 | |
| 252 | def test_symlinked_objects_dir_raises(self, tmp_path: pathlib.Path) -> None: |
| 253 | """If .muse/objects/ is a symlink, write_object must raise ValueError.""" |
| 254 | repo = _make_real_repo(tmp_path) |
| 255 | attacker = tmp_path / "attacker" |
| 256 | attacker.mkdir() |
| 257 | import shutil |
| 258 | shutil.rmtree(objects_dir(repo)) |
| 259 | (objects_dir(repo)).symlink_to(attacker) |
| 260 | |
| 261 | content = b"malicious payload" |
| 262 | oid = blob_id(content) |
| 263 | # write_object creates the shard dir, then checks it |
| 264 | with pytest.raises((ValueError, SystemExit)): |
| 265 | write_object(repo, oid, content) |
| 266 | # Verify nothing was written to the attacker dir |
| 267 | assert not any(attacker.rglob("*")), "Data must not be written to symlink target" |
| 268 | |
| 269 | def test_symlinked_shard_dir_raises(self, tmp_path: pathlib.Path) -> None: |
| 270 | """A symlinked shard dir (e.g. objects/ab/ → /tmp/malicious/) is rejected.""" |
| 271 | repo = _make_real_repo(tmp_path) |
| 272 | content = b"shard attack" |
| 273 | oid = blob_id(content) |
| 274 | prefix = split_id(oid)[1][:2] |
| 275 | attacker = tmp_path / "attacker_shard" |
| 276 | attacker.mkdir() |
| 277 | shard = objects_algo_dir(repo) / prefix |
| 278 | shard.mkdir(parents=True, exist_ok=True) |
| 279 | # Replace real shard dir with symlink |
| 280 | import shutil |
| 281 | shutil.rmtree(shard) |
| 282 | shard.symlink_to(attacker) |
| 283 | |
| 284 | with pytest.raises((ValueError, SystemExit)): |
| 285 | write_object(repo, oid, content) |
| 286 | assert not any(attacker.rglob("*")), "No data must reach symlink target" |
| 287 | |
| 288 | def test_write_object_from_path_symlinked_objects_dir_raises( |
| 289 | self, tmp_path: pathlib.Path |
| 290 | ) -> None: |
| 291 | repo = _make_real_repo(tmp_path) |
| 292 | attacker = tmp_path / "attacker" |
| 293 | attacker.mkdir() |
| 294 | import shutil |
| 295 | shutil.rmtree(objects_dir(repo)) |
| 296 | (objects_dir(repo)).symlink_to(attacker) |
| 297 | |
| 298 | src = tmp_path / "source.bin" |
| 299 | src.write_bytes(b"from path content") |
| 300 | oid = blob_id(src.read_bytes()) |
| 301 | with pytest.raises((ValueError, SystemExit)): |
| 302 | write_object_from_path(repo, oid, src) |
| 303 | assert not any(attacker.rglob("*")), "Data must not be written to symlink target" |
| 304 | |
| 305 | |
| 306 | # --------------------------------------------------------------------------- |
| 307 | # write_text_atomic — symlinked parent directory is rejected |
| 308 | # --------------------------------------------------------------------------- |
| 309 | |
| 310 | |
| 311 | class TestWriteTextAtomicSymlink: |
| 312 | def test_normal_write_succeeds(self, tmp_path: pathlib.Path) -> None: |
| 313 | target = tmp_path / "HEAD" |
| 314 | write_text_atomic(target, "ref: refs/heads/main\n") |
| 315 | assert target.read_text() == "ref: refs/heads/main\n" |
| 316 | |
| 317 | def test_symlinked_parent_raises(self, tmp_path: pathlib.Path) -> None: |
| 318 | """If the parent directory is a symlink, write_text_atomic must raise.""" |
| 319 | real_dir = tmp_path / "real" |
| 320 | real_dir.mkdir() |
| 321 | attacker = tmp_path / "attacker" |
| 322 | attacker.mkdir() |
| 323 | link_dir = tmp_path / "link_dir" |
| 324 | link_dir.symlink_to(attacker) |
| 325 | target = link_dir / "HEAD" |
| 326 | |
| 327 | with pytest.raises(ValueError, match="symbolic link"): |
| 328 | write_text_atomic(target, "ref: refs/heads/main\n") |
| 329 | # Verify attacker dir untouched |
| 330 | assert not any(attacker.iterdir()), "No data must reach symlink target" |
| 331 | |
| 332 | def test_symlink_at_destination_is_replaced(self, tmp_path: pathlib.Path) -> None: |
| 333 | """POSIX os.replace on a symlink replaces the symlink entry itself. |
| 334 | |
| 335 | This is the SAFE case: writing HEAD when HEAD is a symlink replaces |
| 336 | the symlink with a real file — data goes to .muse/HEAD, not to the |
| 337 | symlink target. This test documents that behaviour is preserved. |
| 338 | """ |
| 339 | real_parent = tmp_path / "muse_dir" |
| 340 | real_parent.mkdir() |
| 341 | elsewhere = tmp_path / "elsewhere.txt" |
| 342 | elsewhere.write_text("original") |
| 343 | |
| 344 | head = real_parent / "HEAD" |
| 345 | head.symlink_to(elsewhere) |
| 346 | assert head.is_symlink() |
| 347 | |
| 348 | write_text_atomic(head, "new content\n") |
| 349 | |
| 350 | # The symlink should be gone — HEAD is now a real file |
| 351 | assert not head.is_symlink(), "symlink at destination must be replaced by real file" |
| 352 | assert head.read_text() == "new content\n" |
| 353 | # The symlink target is untouched |
| 354 | assert elsewhere.read_text() == "original" |
| 355 | |
| 356 | |
| 357 | # --------------------------------------------------------------------------- |
| 358 | # write_shelf_entry — symlinked .muse/shelf/ is rejected |
| 359 | # --------------------------------------------------------------------------- |
| 360 | |
| 361 | |
| 362 | class _MinimalShelfEntry(TypedDict): |
| 363 | id: str |
| 364 | snapshot: dict[str, str] |
| 365 | branch: str |
| 366 | created_at: str |
| 367 | |
| 368 | |
| 369 | class TestWriteShelfEntrySymlink: |
| 370 | def _minimal_entry(self) -> _MinimalShelfEntry: |
| 371 | return { |
| 372 | "id": f"sha256:{'a' * 64}", |
| 373 | "snapshot": {}, |
| 374 | "branch": "main", |
| 375 | "created_at": "2026-01-01T00:00:00+00:00", |
| 376 | } |
| 377 | |
| 378 | def test_normal_write_succeeds(self, tmp_path: pathlib.Path) -> None: |
| 379 | repo = tmp_path / "repo" |
| 380 | (repo / ".muse").mkdir(parents=True) |
| 381 | write_shelf_entry(repo, self._minimal_entry()) |
| 382 | shelf_file = repo / ".muse" / "shelf" / "sha256" / ("a" * 64) |
| 383 | assert shelf_file.exists() |
| 384 | |
| 385 | def test_symlinked_shelf_dir_raises(self, tmp_path: pathlib.Path) -> None: |
| 386 | repo = tmp_path / "repo" |
| 387 | (repo / ".muse").mkdir(parents=True) |
| 388 | attacker = tmp_path / "attacker_shelf" |
| 389 | attacker.mkdir() |
| 390 | shelf = repo / ".muse" / "shelf" |
| 391 | shelf.symlink_to(attacker) |
| 392 | |
| 393 | with pytest.raises(ValueError, match="symlink"): |
| 394 | write_shelf_entry(repo, self._minimal_entry()) |
| 395 | assert not any(attacker.iterdir()), "No data must reach symlink target" |
| 396 | |
| 397 | |
| 398 | # --------------------------------------------------------------------------- |
| 399 | # cleanup_stale_object_temps — symlinked shards are skipped |
| 400 | # --------------------------------------------------------------------------- |
| 401 | |
| 402 | |
| 403 | class TestCleanupSkipsSymlinks: |
| 404 | def test_symlinked_shard_not_entered(self, tmp_path: pathlib.Path) -> None: |
| 405 | """cleanup_stale_object_temps must skip symlinked shard directories.""" |
| 406 | repo = _make_real_repo(tmp_path) |
| 407 | attacker = tmp_path / "attacker" |
| 408 | attacker.mkdir() |
| 409 | # Place a "stale temp" file inside the attacker directory |
| 410 | victim = attacker / ".obj-tmp-should-not-be-deleted" |
| 411 | victim.write_bytes(b"important attacker data") |
| 412 | |
| 413 | # Replace a shard with a symlink → attacker |
| 414 | shard = objects_algo_dir(repo) / "ab" |
| 415 | shard.mkdir(parents=True, exist_ok=True) |
| 416 | import shutil |
| 417 | shutil.rmtree(shard) |
| 418 | shard.symlink_to(attacker) |
| 419 | |
| 420 | removed = cleanup_stale_object_temps(repo) |
| 421 | assert removed == 0, "Symlinked shard must not be entered" |
| 422 | assert victim.exists(), "File in symlink target must not be deleted" |
| 423 | |
| 424 | def test_real_shards_are_cleaned(self, tmp_path: pathlib.Path) -> None: |
| 425 | repo = _make_real_repo(tmp_path) |
| 426 | shard = objects_algo_dir(repo) / "cd" |
| 427 | shard.mkdir(parents=True) |
| 428 | stale = shard / ".obj-tmp-stale123" |
| 429 | stale.write_bytes(b"stale data") |
| 430 | # Backdate mtime so the 60-second age gate treats this file as stale. |
| 431 | os.utime(stale, (0, 0)) |
| 432 | removed = cleanup_stale_object_temps(repo) |
| 433 | assert removed == 1 |
| 434 | assert not stale.exists() |
| 435 | |
| 436 | |
| 437 | class TestCleanupMuseDirSkipsSymlinks: |
| 438 | def test_symlinked_subdir_not_entered(self, tmp_path: pathlib.Path) -> None: |
| 439 | """_cleanup_muse_dir_temps must skip symlinked subdirectories.""" |
| 440 | repo = _make_real_repo(tmp_path) |
| 441 | attacker = tmp_path / "attacker_commits" |
| 442 | attacker.mkdir() |
| 443 | victim = attacker / ".muse-tmp-should-not-be-deleted" |
| 444 | victim.write_bytes(b"important data") |
| 445 | |
| 446 | muse = muse_dir(repo) |
| 447 | import shutil |
| 448 | shutil.rmtree(muse / "commits") |
| 449 | (muse / "commits").symlink_to(attacker) |
| 450 | |
| 451 | removed = _cleanup_muse_dir_temps(muse) |
| 452 | assert removed == 0, "Symlinked subdir must not be entered" |
| 453 | assert victim.exists(), "File in symlink target must not be deleted" |
| 454 | |
| 455 | |
| 456 | # --------------------------------------------------------------------------- |
| 457 | # Tracked-file symlinks — workdir walker skips them |
| 458 | # --------------------------------------------------------------------------- |
| 459 | |
| 460 | |
| 461 | class TestTrackedFileSymlinks: |
| 462 | def test_symlink_to_sensitive_file_not_staged(self, tmp_path: pathlib.Path) -> None: |
| 463 | """A tracked file that is a symlink is silently excluded from the manifest. |
| 464 | |
| 465 | The workdir walker uses os.lstat + S_ISREG, so symlinks are never |
| 466 | hashed or stored — even if they point to /etc/passwd. |
| 467 | """ |
| 468 | from muse.core.snapshot import build_snapshot_manifest |
| 469 | |
| 470 | repo = _make_real_repo(tmp_path) |
| 471 | workdir = repo |
| 472 | |
| 473 | # Create a real file (should be tracked) |
| 474 | real_file = workdir / "song.mid" |
| 475 | real_file.write_bytes(b"\x4d\x54\x68\x64" + b"\x00" * 10) |
| 476 | |
| 477 | # Create a symlink to a sensitive target |
| 478 | sensitive = tmp_path / "sensitive.txt" |
| 479 | sensitive.write_text("secret data") |
| 480 | malicious_link = workdir / "malicious.txt" |
| 481 | malicious_link.symlink_to(sensitive) |
| 482 | |
| 483 | manifest = build_snapshot_manifest(workdir) |
| 484 | assert "song.mid" in manifest, "real file must be tracked" |
| 485 | assert "malicious.txt" not in manifest, "symlink must NOT be in manifest" |
| 486 | |
| 487 | def test_symlink_to_nonexistent_target_not_staged(self, tmp_path: pathlib.Path) -> None: |
| 488 | from muse.core.snapshot import build_snapshot_manifest |
| 489 | |
| 490 | repo = _make_real_repo(tmp_path) |
| 491 | workdir = repo |
| 492 | dangling = workdir / "dangling.txt" |
| 493 | dangling.symlink_to(tmp_path / "nonexistent") |
| 494 | |
| 495 | manifest = build_snapshot_manifest(workdir) |
| 496 | assert "dangling.txt" not in manifest |
| 497 | |
| 498 | |
| 499 | # --------------------------------------------------------------------------- |
| 500 | # Stress: concurrent symlink-swap during write_object |
| 501 | # --------------------------------------------------------------------------- |
| 502 | |
| 503 | |
| 504 | class TestConcurrentSymlinkSwapStress: |
| 505 | def test_concurrent_symlink_swap_does_not_corrupt( |
| 506 | self, tmp_path: pathlib.Path |
| 507 | ) -> None: |
| 508 | """50 concurrent symlink-swap threads racing against write_object. |
| 509 | |
| 510 | write_object either succeeds (writes to the real location) or raises |
| 511 | ValueError (detects the symlink). It must never silently write to |
| 512 | the attacker-controlled location. |
| 513 | """ |
| 514 | repo = _make_real_repo(tmp_path) |
| 515 | attacker = tmp_path / "attacker_stress" |
| 516 | attacker.mkdir() |
| 517 | obj_dir = objects_dir(repo) |
| 518 | |
| 519 | content = b"stress test object symlink-check" |
| 520 | oid = blob_id(content) |
| 521 | shard_prefix = oid[:2] |
| 522 | shard_dir = obj_dir / shard_prefix |
| 523 | |
| 524 | errors: list[str] = [] |
| 525 | swap_active = threading.Event() |
| 526 | stop_swapping = threading.Event() |
| 527 | |
| 528 | def swap_shard() -> None: |
| 529 | """Repeatedly swap shard dir between real and symlink.""" |
| 530 | import shutil |
| 531 | while not stop_swapping.is_set(): |
| 532 | swap_active.set() |
| 533 | # Replace real shard with symlink |
| 534 | try: |
| 535 | if shard_dir.exists() and not shard_dir.is_symlink(): |
| 536 | shutil.rmtree(shard_dir) |
| 537 | shard_dir.symlink_to(attacker) |
| 538 | time.sleep(0.0005) |
| 539 | # Restore real shard |
| 540 | if shard_dir.is_symlink(): |
| 541 | shard_dir.unlink() |
| 542 | shard_dir.mkdir(exist_ok=True) |
| 543 | except OSError: |
| 544 | pass |
| 545 | |
| 546 | swapper = threading.Thread(target=swap_shard, daemon=True) |
| 547 | swapper.start() |
| 548 | swap_active.wait(timeout=1.0) |
| 549 | |
| 550 | write_errors = 0 |
| 551 | write_successes = 0 |
| 552 | for _ in range(50): |
| 553 | try: |
| 554 | write_object(repo, oid, content) |
| 555 | write_successes += 1 |
| 556 | except (ValueError, OSError, SystemExit): |
| 557 | write_errors += 1 |
| 558 | |
| 559 | stop_swapping.set() |
| 560 | swapper.join(timeout=2.0) |
| 561 | |
| 562 | # The attacker directory must remain empty regardless of outcome. |
| 563 | attacker_files = list(attacker.rglob("*")) |
| 564 | if attacker_files: |
| 565 | errors.append( |
| 566 | f"Data leaked to attacker dir: {[str(f) for f in attacker_files]}" |
| 567 | ) |
| 568 | |
| 569 | assert not errors, "\n".join(errors) |
| 570 | # Sanity: at least some operations completed (either succeeded or were blocked). |
| 571 | assert write_successes + write_errors == 50 |
| 572 | |
| 573 | |
| 574 | # --------------------------------------------------------------------------- |
| 575 | # Integration: end-to-end CLI commands with symlinked .muse/ |
| 576 | # --------------------------------------------------------------------------- |
| 577 | |
| 578 | |
| 579 | class TestCLIWithSymlinkedMuse: |
| 580 | def test_muse_status_rejects_symlinked_muse(self, tmp_path: pathlib.Path) -> None: |
| 581 | """muse status must fail when .muse/ is a symlink.""" |
| 582 | real_muse = tmp_path / "real_muse" |
| 583 | real_muse.mkdir() |
| 584 | for sub in ("objects", "commits", "snapshots", "refs/heads", "tags"): |
| 585 | (real_muse / sub).mkdir(parents=True) |
| 586 | (real_muse / "HEAD").write_text("ref: refs/heads/main\n") |
| 587 | (real_muse / "repo.json").write_text('{"repo_id": "test"}') |
| 588 | |
| 589 | repo = tmp_path / "repo" |
| 590 | repo.mkdir() |
| 591 | muse_dir(repo).symlink_to(real_muse) |
| 592 | |
| 593 | runner = CliRunner() |
| 594 | # find_repo_root won't find a real .muse/ → should exit non-zero |
| 595 | result = runner.invoke(None, ["status"], env={"MUSE_REPO_ROOT": str(repo)}) |
| 596 | assert result.exit_code != 0 |
| 597 | |
| 598 | def test_muse_status_accepts_real_muse(self, tmp_path: pathlib.Path) -> None: |
| 599 | """muse status does not reject a real .muse/ directory as a symlink.""" |
| 600 | repo = _make_real_repo(tmp_path) |
| 601 | (config_toml_path(repo)).write_text( |
| 602 | "[core]\nauthor = \"test\"\n" |
| 603 | ) |
| 604 | (heads_dir(repo) / "main").write_text("") |
| 605 | (head_path(repo)).write_text("ref: refs/heads/main\n") |
| 606 | |
| 607 | runner = CliRunner() |
| 608 | result = runner.invoke( |
| 609 | None, ["status"], |
| 610 | env={"MUSE_REPO_ROOT": str(repo)}, |
| 611 | ) |
| 612 | # Must not complain about symlinks on a real .muse/. |
| 613 | assert "symbolic link" not in result.output.lower() |