Validate IRC DCC offers before download (#964)

2026-10-05 22:05:50 +01:00 · 2026-05-09 13:19:22 +01:00
parent fbbff8f715
commit f5fafd2265
6 changed files with 268 additions and 12 deletions
@@ -0,0 +1,82 @@
+import socket
+
+import pytest
+
+from shelfmark.release_sources.irc.dcc import (
+    DCCOffer,
+    DCCParseError,
+    DCCSecurityError,
+    download_dcc,
+    parse_dcc_send,
+    safe_dcc_filename,
+    validate_dcc_endpoint,
+)
+
+
+def test_safe_dcc_filename_allows_plain_filenames() -> None:
+    assert safe_dcc_filename("results.txt") == "results.txt"
+    assert safe_dcc_filename("Author - Title.epub") == "Author - Title.epub"
+
+
+@pytest.mark.parametrize(
+    "filename",
+    [
+        "",
+        ".",
+        "..",
+        "../outside.txt",
+        "/tmp/outside.txt",
+        r"..\outside.txt",
+        r"C:\temp\outside.txt",
+    ],
+)
+def test_safe_dcc_filename_rejects_paths(filename: str) -> None:
+    with pytest.raises(DCCSecurityError):
+        safe_dcc_filename(filename)
+
+
+@pytest.mark.parametrize(
+    "ip",
+    [
+        "127.0.0.1",
+        "10.0.0.1",
+        "172.16.0.1",
+        "192.168.1.1",
+        "169.254.169.254",
+        "0.0.0.0",
+    ],
+)
+def test_validate_dcc_endpoint_rejects_non_public_ips(ip: str) -> None:
+    with pytest.raises(DCCSecurityError):
+        validate_dcc_endpoint(DCCOffer(filename="book.epub", ip=ip, port=1234, size=1))
+
+
+@pytest.mark.parametrize("port", [0, 65536])
+def test_validate_dcc_endpoint_rejects_invalid_ports(port: int) -> None:
+    with pytest.raises(DCCSecurityError):
+        validate_dcc_endpoint(DCCOffer(filename="book.epub", ip="8.8.8.8", port=port, size=1))
+
+
+def test_validate_dcc_endpoint_allows_public_endpoint() -> None:
+    validate_dcc_endpoint(DCCOffer(filename="book.epub", ip="8.8.8.8", port=443, size=1))
+
+
+def test_parse_dcc_send_rejects_out_of_range_ip_integer() -> None:
+    with pytest.raises(DCCParseError):
+        parse_dcc_send('DCC SEND "book.epub" 999999999999999999 443 1')
+
+
+def test_download_dcc_rejects_private_endpoint_before_socket_connect(
+    monkeypatch,
+    tmp_path,
+) -> None:
+    def fail_socket(*_args: object, **_kwargs: object) -> socket.socket:
+        raise AssertionError("download should reject the endpoint before opening a socket")
+
+    monkeypatch.setattr(socket, "socket", fail_socket)
+
+    with pytest.raises(DCCSecurityError):
+        download_dcc(
+            DCCOffer(filename="book.epub", ip="127.0.0.1", port=1234, size=1),
+            tmp_path / "book.epub",
+        )