Skip to content

fix(auth): fall back when certificate callbacks return empty credentials #18435

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
Shubham-Padkonde wants to merge 2 commits into
base: main
Choose a base branch
from
Open

fix(auth): fall back when certificate callbacks return empty credentials #18435

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
13f7154
fix(auth): fall back when certificate callbacks return empty credentials
Shubham-Padkonde Sep 22, 2026
585dcd9
chore: merge main and retain empty certificate callback tests
Shubham-Padkonde Oct 17, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 2 additions & 1 deletion packages/google-auth/google/auth/aio/transport/mtls.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -173,7 +173,8 @@ async def get_client_cert_and_key(client_cert_callback=None):
cert, key = await result
else:
cert, key = result
return True, cert, key
if cert and key:
return True, cert, key

has_cert, cert, key, _ = await get_client_ssl_credentials()
return has_cert, cert, key
Expand Down
3 changes: 2 additions & 1 deletion packages/google-auth/google/auth/transport/_mtls_helper.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -760,7 +760,8 @@ def get_client_cert_and_key(client_cert_callback=None):
"""
if client_cert_callback:
cert, key = client_cert_callback()
return True, cert, key
if cert and key:
return True, cert, key

has_cert, cert, key, _ = get_client_ssl_credentials(generate_encrypted_key=False)
return has_cert, cert, key
Expand Down
17 changes: 17 additions & 0 deletions packages/google-auth/tests/transport/test__mtls_helper.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2069,6 +2069,23 @@ def test_is_mtls_endpoint_false(self, url):
assert _mtls_helper.is_mtls_endpoint(url) is False


@pytest.mark.parametrize(
"callback_result", [(None, None), (b"", b""), (b"cert", None), (None, b"key")]
)
@pytest.mark.parametrize(
"default_result",
[(True, b"default-cert", b"default-key", None), (False, None, None, None)],
)
def test_empty_client_cert_callback_uses_default(callback_result, default_result):
callback = mock.Mock(return_value=callback_result)
with mock.patch.object(
_mtls_helper, "get_client_ssl_credentials", return_value=default_result
) as get_default:
assert _mtls_helper.get_client_cert_and_key(callback) == default_result[:3]
callback.assert_called_once_with()
get_default.assert_called_once_with(generate_encrypted_key=False)


class TestReadCredentialBundleFile(object):
@pytest.mark.parametrize("key_index", [0, 1])
def test_single_cert_and_key(self, tmpdir, key_index):
Expand Down
22 changes: 22 additions & 0 deletions packages/google-auth/tests/transport/test_aio_mtls_helper.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -217,3 +217,25 @@ async def test_make_client_cert_ssl_context_setup_error(self, mock_secure_paths)

assert "Failed to load client certificate" in str(exc_info.value)
assert isinstance(exc_info.value.__cause__, OSError)


@pytest.mark.asyncio
@pytest.mark.parametrize(
"callback_result", [(None, None), (b"", b""), (b"cert", None), (None, b"key")]
)
@pytest.mark.parametrize(
"default_result",
[(True, b"default-cert", b"default-key", None), (False, None, None, None)],
)
@pytest.mark.parametrize("async_callback", [False, True])
async def test_empty_client_cert_callback_uses_default(
callback_result, default_result, async_callback
):
callback_type = mock.AsyncMock if async_callback else mock.Mock
callback = callback_type(return_value=callback_result)
with mock.patch.object(
mtls, "get_client_ssl_credentials", return_value=default_result
) as get_default:
assert await mtls.get_client_cert_and_key(callback) == default_result[:3]
callback.assert_called_once_with()
get_default.assert_awaited_once_with()
Loading