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fix(parity): rsync 3.4.1 symlink and special-node semantics (#287, #288)

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#287:
- --safe-links: keep safe in-tree links AS symlinks and skip unsafe
  (absolute or ".."-escaping) ones, mirroring rsync's unsafe_symlink().
  Skipped links are recorded as delete-protected so --delete does not
  remove their destination mirror (no silent data loss).
- --copy-unsafe-links: preserve safe links as symlinks and dereference
  only unsafe ones.
- --munge-links: receiver-side rewrite storing /rsyncd-munged/-prefixed
  targets (rsync parity), replacing the no-op #SYMLINK sender prefix.
- -l: store the target verbatim, including absolute and ".." targets
  (rsync -l parity); the old receiver containment silently dropped them.

#288:
- --specials: recreate unix-domain sockets via mknod(S_IFSOCK), which
  Linux permits unprivileged; keep EEXIST/EPERM skip behavior.
- --copy-devices: copy a device's content into a regular file when
  requested; skip unrequested non-regular entries like rsync's default.
This commit is contained in:
TapTap
2026-09-15 21:57:48 +02:00
parent 23552e823d
commit ea4ab661b4
8 changed files with 573 additions and 250 deletions
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tests/integration/test_features.py
+204 -66
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@@ -92,54 +92,63 @@ class TestDeviceSpecial:
assert stat.S_ISFIFO(os.stat(os.path.join(received, "pipe.fifo")).st_mode)
@pytest.mark.ci
def test_specials_socket_source_skipped_safely(self):
"""A socket cannot be recreated by any standard filesystem call, so
--specials must skip it with a note and still complete the run (the
adjacent regular file transfers normally; no socket node appears)."""
def test_specials_recreates_socket(self, shared_server):
"""--specials recreates a unix-domain socket with mknod(S_IFSOCK), which
Linux permits unprivileged; the adjacent regular file still transfers."""
self._setup()
sock_path = os.path.join(DEVICE_SOURCE, "source.sock")
s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
server, port = _start_captured_server()
try:
s.bind(sock_path)
result, _ = run_client(DEVICE_SOURCE, DEVICE_DEST,
flags=["--specials"], port=port)
flags=["--specials"], port=shared_server.port)
finally:
s.close()
out, err = _stop_captured_server(server)
assert result.returncode == 0, f"Exit {result.returncode}: {result.stderr[:200]}"
received = get_dest_received_dir(DEVICE_DEST, DEVICE_SOURCE)
with open(os.path.join(received, "plain.txt")) as f:
assert f.read() == "regular content\n"
assert not os.path.lexists(os.path.join(received, "source.sock")), (
"socket source must be skipped, not materialized"
)
assert "socket not recreated" in (out + err), (
f"receiver did not log the documented socket skip: out={out!r} err={err!r}"
dest_sock = os.path.join(received, "source.sock")
assert os.path.lexists(dest_sock), "socket source was not recreated"
assert stat.S_ISSOCK(os.lstat(dest_sock).st_mode), (
"socket source must be recreated as a socket node"
)
@pytest.mark.ci
def test_special_default_skips_non_regular(self, shared_server):
"""Without --specials, rsync skips a FIFO/socket as a non-regular file;
FastSync must skip it (never copy it as an empty regular file)."""
self._setup()
os.mkfifo(os.path.join(DEVICE_SOURCE, "skip.fifo"))
sock_path = os.path.join(DEVICE_SOURCE, "skip.sock")
s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
try:
s.bind(sock_path)
result, _ = run_client(DEVICE_SOURCE, DEVICE_DEST, flags=[], port=shared_server.port)
finally:
s.close()
assert result.returncode == 0, f"Exit {result.returncode}: {result.stderr[:200]}"
received = get_dest_received_dir(DEVICE_DEST, DEVICE_SOURCE)
assert not os.path.lexists(os.path.join(received, "skip.fifo"))
assert not os.path.lexists(os.path.join(received, "skip.sock"))
with open(os.path.join(received, "plain.txt")) as f:
assert f.read() == "regular content\n"
@pytest.mark.ci
@pytest.mark.parametrize("flags", [["--copy-devices"], ["--copy-devices", "--sendfile"]])
def test_copy_devices_fifo_becomes_regular_file(self, shared_server, flags):
"""--copy-devices treats a special source as an ordinary regular-file
copy: a FIFO (st_size 0) becomes a zero-length REGULAR file on the
destination (never a FIFO, never a hang), and the run succeeds. The
--sendfile variant previously blocked forever in the sendfile open();
the non-regular source now falls back to the buffered read path, so it
must complete within the bounded-time assertion below."""
def test_copy_devices_skips_fifo_without_specials(self, shared_server, flags):
"""rsync's --copy-devices applies to device nodes only; a FIFO/socket is
a non-regular entry and is skipped unless --specials is also given. In
particular it must never hang in the sendfile open()."""
self._setup()
os.mkfifo(os.path.join(DEVICE_SOURCE, "device_copy.fifo"))
result, dur = run_client(DEVICE_SOURCE, DEVICE_DEST,
flags=flags, port=shared_server.port)
assert result.returncode == 0, f"Exit {result.returncode}: {result.stderr[:200]}"
received = get_dest_received_dir(DEVICE_DEST, DEVICE_SOURCE)
copied = os.path.join(received, "device_copy.fifo")
assert os.path.lexists(copied), "copy-devices source was not transferred"
st = os.lstat(copied)
assert stat.S_ISREG(st.st_mode), (
f"copy-devices must produce a regular file, got mode {oct(st.st_mode)}"
assert not os.path.lexists(os.path.join(received, "device_copy.fifo")), (
"a FIFO under --copy-devices alone must be skipped, not materialized"
)
assert st.st_size == 0, f"expected a size-bounded 0-byte copy, got {st.st_size}"
assert dur < 60, f"{' '.join(flags)} hung on a FIFO source"
def test_write_devices_non_crash(self, shared_server):
@@ -220,6 +229,24 @@ class TestDeviceSpecial:
assert stat.S_ISCHR(st.st_mode)
assert os.major(st.st_rdev) == 1 and os.minor(st.st_rdev) == 3
@pytest.mark.skipif(os.geteuid() != 0, reason="requires root to create device nodes")
def test_copy_devices_copies_device_as_regular(self, shared_server):
"""Root-only: --copy-devices copies a device's content into an ordinary
regular file instead of recreating the node. /dev/null (1,3) has size 0,
so the result is a 0-byte REGULAR file."""
self._setup()
src_dev = os.path.join(DEVICE_SOURCE, "copieddev")
os.mknod(src_dev, stat.S_IFCHR | 0o666, os.makedev(1, 3))
result, _ = run_client(DEVICE_SOURCE, DEVICE_DEST,
flags=["-a", "--copy-devices"], port=shared_server.port)
assert result.returncode == 0, f"Exit {result.returncode}: {result.stderr[:200]}"
received = get_dest_received_dir(DEVICE_DEST, DEVICE_SOURCE)
st = os.lstat(os.path.join(received, "copieddev"))
assert stat.S_ISREG(st.st_mode), (
f"--copy-devices must produce a regular file, got mode {oct(st.st_mode)}"
)
assert st.st_size == 0
def test_m_remove_source_files_keeps_recreated_fifo(self, shared_server):
"""--threads --remove-source-files --specials: a recreated FIFO must NOT be
acknowledged as a removable source (its outcome must not shift the
@@ -5150,8 +5177,10 @@ class TestSymlinkTrust:
os.symlink("realfile.txt", os.path.join(source, "link_file"))
os.symlink("realdir", os.path.join(source, "link_dir"))
result, _ = run_client(source, dest, flags=["-k"], port=shared_server.port)
assert result.returncode == 0, f"-k failed: {(result.stderr or result.stdout)[:300]}"
# -k only dereferences directory symlinks; file symlinks need -l to be
# carried as symlinks (rsync skips them otherwise).
result, _ = run_client(source, dest, flags=["-l", "-k"], port=shared_server.port)
assert result.returncode == 0, f"-l -k failed: {(result.stderr or result.stdout)[:300]}"
received = get_dest_received_dir(dest, source)
# link -> realdir dereferences into a real directory tree...
@@ -5191,9 +5220,13 @@ class TestSymlinkTrust:
# ... and the file is written beneath it, through to the referent dir.
assert os.path.isfile(os.path.join(parent, "realdir", "file.txt"))
def test_munge_links_unmunged_target_and_containment(self, shared_server):
source = os.path.join(TEST_DATA_DIR, "symlink_trust_munge")
dest = os.path.join(TEST_DATA_DIR, "symlink_trust_munge_dst")
@pytest.mark.ci
def test_munge_links_prefixes_targets(self, shared_server):
# rsync's --munge-links is a RECEIVER-side rewrite: every stored target
# gets the /rsyncd-munged/ prefix, making the link unusable while that
# directory does not exist.
source = os.path.join(TEST_DATA_DIR, "symlink_munge")
dest = os.path.join(TEST_DATA_DIR, "symlink_munge_dst")
clean_dir(source)
clean_dir(dest)
with open(os.path.join(source, "a.txt"), "wb") as f:
@@ -5207,19 +5240,15 @@ class TestSymlinkTrust:
assert result.returncode == 0, f"--munge-links failed: {(result.stderr or result.stdout)[:300]}"
received = get_dest_received_dir(dest, source)
# The safe symlink is created with its correct (unmunged) target.
good = os.path.join(received, "good")
assert os.path.islink(good)
assert os.readlink(good) == "a.txt"
# A target that would escape the receive root is contained (skip: never
# transmitted, so nothing is created at the destination).
assert not os.path.lexists(os.path.join(received, "abs_escape"))
assert not os.path.lexists(os.path.join(received, "dotdot_escape"))
assert os.readlink(os.path.join(received, "good")) == "/rsyncd-munged/a.txt"
assert os.readlink(os.path.join(received, "abs_escape")) == "/rsyncd-munged//etc/passwd"
assert os.readlink(os.path.join(received, "dotdot_escape")) == "/rsyncd-munged/../../escape"
assert os.path.isfile(os.path.join(received, "a.txt"))
@pytest.mark.ci
def test_links_copies_symlinks_as_symlinks(self, shared_server):
source = os.path.join(TEST_DATA_DIR, "symlink_trust_links")
dest = os.path.join(TEST_DATA_DIR, "symlink_trust_links_dst")
source = os.path.join(TEST_DATA_DIR, "symlink_links")
dest = os.path.join(TEST_DATA_DIR, "symlink_links_dst")
clean_dir(source)
clean_dir(dest)
os.makedirs(os.path.join(source, "realdir"))
@@ -5238,48 +5267,157 @@ class TestSymlinkTrust:
assert os.path.islink(os.path.join(received, "ld"))
assert os.readlink(os.path.join(received, "ld")) == "realdir"
def test_receiver_contains_absolute_target_even_without_munge(self, shared_server):
# The trust boundary is symmetric and enforced receiver-side: a plain -l
# (no --munge-links) run must refuse to materialize an out-of-root
# absolute symlink target, while still copying a legitimate in-root one.
source = os.path.join(TEST_DATA_DIR, "symlink_trust_abs")
dest = os.path.join(TEST_DATA_DIR, "symlink_trust_abs_dst")
@pytest.mark.ci
def test_links_preserves_absolute_and_dotdot_targets(self, shared_server):
# rsync -l parity: -l stores a symlink target verbatim, including an
# absolute target and an in-tree ".." target (no silent drop).
source = os.path.join(TEST_DATA_DIR, "symlink_links_verbatim")
dest = os.path.join(TEST_DATA_DIR, "symlink_links_verbatim_dst")
clean_dir(source)
clean_dir(dest)
with open(os.path.join(source, "a.txt"), "wb") as f:
f.write(b"a\n")
os.makedirs(os.path.join(source, "sub"))
os.symlink("a.txt", os.path.join(source, "good"))
os.symlink("/etc/passwd", os.path.join(source, "unsafe_abs"))
os.symlink("../a.txt", os.path.join(source, "sub", "up"))
result, _ = run_client(source, dest, flags=["-l"], port=shared_server.port)
assert result.returncode == 0, f"-l failed: {(result.stderr or result.stdout)[:300]}"
received = get_dest_received_dir(dest, source)
good = os.path.join(received, "good")
assert os.path.islink(good)
assert os.readlink(good) == "a.txt"
# The absolute (non-contained) target was not materialized at the dest.
assert not os.path.lexists(os.path.join(received, "unsafe_abs"))
assert os.readlink(os.path.join(received, "good")) == "a.txt"
assert os.readlink(os.path.join(received, "unsafe_abs")) == "/etc/passwd"
assert os.readlink(os.path.join(received, "sub", "up")) == "../a.txt"
def test_links_does_not_strip_munge_prefix_without_munge(self, shared_server):
# A source symlink whose target genuinely begins with the #SYMLINK/ marker
# must round-trip verbatim under plain -l: the receiver only unmunges when
# the negotiated --munge-links policy is on, never unconditionally.
source = os.path.join(TEST_DATA_DIR, "symlink_trust_prefix")
dest = os.path.join(TEST_DATA_DIR, "symlink_trust_prefix_dst")
@pytest.mark.ci
def test_safe_links_keeps_safe_skips_unsafe(self, shared_server):
# --safe-links keeps symlinks that stay inside the transfer tree (even
# with a ".." that does not climb out) and drops absolute / escaping /
# internally-".."-bearing targets.
source = os.path.join(TEST_DATA_DIR, "symlink_safe")
dest = os.path.join(TEST_DATA_DIR, "symlink_safe_dst")
clean_dir(source)
clean_dir(dest)
with open(os.path.join(source, "a.txt"), "wb") as f:
f.write(b"a\n")
os.makedirs(os.path.join(source, "sub"))
os.symlink("a.txt", os.path.join(source, "safe_rel"))
os.symlink("../a.txt", os.path.join(source, "sub", "up"))
os.symlink("/etc/passwd", os.path.join(source, "abs"))
os.symlink("../outside.txt", os.path.join(source, "esc"))
os.symlink("sub/../a.txt", os.path.join(source, "internal"))
result, _ = run_client(source, dest, flags=["-l", "--safe-links"],
port=shared_server.port)
assert result.returncode == 0, f"--safe-links failed: {(result.stderr or result.stdout)[:300]}"
received = get_dest_received_dir(dest, source)
assert os.readlink(os.path.join(received, "safe_rel")) == "a.txt"
assert os.readlink(os.path.join(received, "sub", "up")) == "../a.txt"
for unsafe in ("abs", "esc", "internal"):
assert not os.path.lexists(os.path.join(received, unsafe)), (
f"{unsafe} must be skipped by --safe-links"
)
@pytest.mark.ci
def test_safe_links_protects_dest_from_delete(self):
# rsync counts an unsafe link ignored by --safe-links as present in the
# transfer, so its destination mirror survives --delete. FastSync must
# not delete it (no silent data loss). Own server: deletion needs
# --allow-delete, which the shared session server does not grant.
source = os.path.join(TEST_DATA_DIR, "symlink_safe_delete")
dest = os.path.join(TEST_DATA_DIR, "symlink_safe_delete_dst")
clean_dir(source)
clean_dir(dest)
with open(os.path.join(source, "keep.txt"), "wb") as f:
f.write(b"keep\n")
os.symlink("/etc/passwd", os.path.join(source, "unsafe_abs"))
with ServerManager() as server:
server.start(extra_args=["--allow-delete"])
received = get_dest_received_dir(dest, source)
os.makedirs(received, exist_ok=True)
mirror = os.path.join(received, "unsafe_abs")
with open(mirror, "wb") as f:
f.write(b"existing destination data\n")
extra = os.path.join(received, "extra.txt")
with open(extra, "wb") as f:
f.write(b"extra\n")
result, _ = run_client(source, dest, flags=["-l", "--safe-links", "--delete"],
port=server.port)
assert result.returncode == 0, (
f"--delete --safe-links failed: {(result.stderr or result.stdout)[:300]}"
)
assert os.path.exists(mirror), (
"a destination mirror of a --safe-links-skipped link must survive --delete"
)
assert not os.path.exists(extra), "a genuine extra must still be deleted"
@pytest.mark.ci
def test_copy_unsafe_links_derefs_only_unsafe(self, shared_server):
# --copy-unsafe-links keeps safe symlinks and dereferences unsafe ones
# (absolute or escaping) into regular files.
source = os.path.join(TEST_DATA_DIR, "symlink_copy_unsafe")
dest = os.path.join(TEST_DATA_DIR, "symlink_copy_unsafe_dst")
clean_dir(source)
clean_dir(dest)
with open(os.path.join(source, "a.txt"), "wb") as f:
f.write(b"a\n")
with open(os.path.join(source, "refer.txt"), "wb") as f:
f.write(b"refer\n")
external = os.path.join(TEST_DATA_DIR, "symlink_copy_unsafe_external.txt")
with open(external, "wb") as f:
f.write(b"external\n")
os.symlink("a.txt", os.path.join(source, "safe_rel"))
os.symlink("refer.txt", os.path.join(source, "from_rel"))
os.symlink("../symlink_copy_unsafe_external.txt", os.path.join(source, "esc"))
os.symlink("/etc/hostname", os.path.join(source, "abs"))
result, _ = run_client(source, dest, flags=["-l", "--copy-unsafe-links"],
port=shared_server.port)
assert result.returncode == 0, (
f"--copy-unsafe-links failed: {(result.stderr or result.stdout)[:300]}"
)
received = get_dest_received_dir(dest, source)
assert os.path.islink(os.path.join(received, "safe_rel"))
assert os.readlink(os.path.join(received, "safe_rel")) == "a.txt"
assert os.path.islink(os.path.join(received, "from_rel")), (
"a safe symlink must be preserved, not dereferenced"
)
assert os.readlink(os.path.join(received, "from_rel")) == "refer.txt"
# An escaping (..) symlink and an absolute symlink are both dereferenced
# into regular files holding the referent's content.
assert not os.path.islink(os.path.join(received, "esc"))
with open(os.path.join(received, "esc"), "rb") as f:
assert f.read() == b"external\n"
assert not os.path.islink(os.path.join(received, "abs"))
assert os.path.isfile(os.path.join(received, "abs"))
def test_munge_prefix_roundtrip(self, shared_server):
# A source target that already begins with /rsyncd-munged/ round-trips:
# plain -l stores it verbatim, and --munge-links strips on the sender
# then re-munges on the receiver, yielding the same stored value.
source = os.path.join(TEST_DATA_DIR, "symlink_munge_roundtrip")
dest = os.path.join(TEST_DATA_DIR, "symlink_munge_roundtrip_dst")
clean_dir(source)
clean_dir(dest)
with open(os.path.join(source, "realfile.txt"), "wb") as f:
f.write(b"real\n")
os.symlink("#SYMLINK/realfile.txt", os.path.join(source, "prefixed"))
os.symlink("/rsyncd-munged/realfile.txt", os.path.join(source, "prefixed"))
os.symlink("#SYMLINK/realfile.txt", os.path.join(source, "oldmarker"))
result, _ = run_client(source, dest, flags=["-l"], port=shared_server.port)
assert result.returncode == 0, f"-l failed: {(result.stderr or result.stdout)[:300]}"
received = get_dest_received_dir(dest, source)
prefixed = os.path.join(received, "prefixed")
assert os.path.islink(prefixed)
assert os.readlink(prefixed) == "#SYMLINK/realfile.txt"
for flags, oldmarker_target in (
(["-l"], "#SYMLINK/realfile.txt"),
(["-l", "--munge-links"], "/rsyncd-munged/#SYMLINK/realfile.txt"),
):
clean_dir(dest)
result, _ = run_client(source, dest, flags=flags, port=shared_server.port)
assert result.returncode == 0, (
f"{' '.join(flags)} failed: {(result.stderr or result.stdout)[:300]}"
)
received = get_dest_received_dir(dest, source)
assert os.readlink(os.path.join(received, "prefixed")) == "/rsyncd-munged/realfile.txt"
assert os.readlink(os.path.join(received, "oldmarker")) == oldmarker_target
def _xattr_supported(path):
"""True when the filesystem hosting `path` supports user xattrs."""
try: