From 5ccdfda7476a9667ee3dadc89be845fae45c1206 Mon Sep 17 00:00:00 2001
From: ElCruncharino <59633028+ElCruncharino@users.noreply.github.com>
Date: Thu, 8 Jan 2026 10:39:47 -0500
Subject: [PATCH] Add asyncio-level timeout to Backblaze B2 uploads (#160468)

---
 .../components/backblaze_b2/backup.py         | 31 +++++--
 tests/components/backblaze_b2/test_backup.py  | 92 +++++++++++++++++++
 2 files changed, 117 insertions(+), 6 deletions(-)

diff --git a/homeassistant/components/backblaze_b2/backup.py b/homeassistant/components/backblaze_b2/backup.py
index a9a15e634cf7..f0acc5218bc9 100644
--- a/homeassistant/components/backblaze_b2/backup.py
+++ b/homeassistant/components/backblaze_b2/backup.py
@@ -36,6 +36,10 @@ _LOGGER = logging.getLogger(__name__)
 # Cache TTL for backup list (in seconds)
 CACHE_TTL = 300
 
+# Timeout for upload operations (in seconds)
+# This prevents uploads from hanging indefinitely
+UPLOAD_TIMEOUT = 43200  # 12 hours (matches B2 HTTP timeout)
+
 
 def suggested_filenames(backup: AgentBackup) -> tuple[str, str]:
     """Return the suggested filenames for the backup and metadata files."""
@@ -329,13 +333,28 @@ class BackblazeBackupAgent(BackupAgent):
         _LOGGER.debug("Uploading backup file %s with streaming", filename)
         try:
             content_type, _ = mimetypes.guess_type(filename)
-            file_version = await self._hass.async_add_executor_job(
-                self._upload_unbound_stream_sync,
-                reader,
-                filename,
-                content_type or "application/x-tar",
-                file_info,
+            file_version = await asyncio.wait_for(
+                self._hass.async_add_executor_job(
+                    self._upload_unbound_stream_sync,
+                    reader,
+                    filename,
+                    content_type or "application/x-tar",
+                    file_info,
+                ),
+                timeout=UPLOAD_TIMEOUT,
             )
+        except TimeoutError:
+            _LOGGER.error(
+                "Upload of %s timed out after %s seconds", filename, UPLOAD_TIMEOUT
+            )
+            reader.abort()
+            raise BackupAgentError(
+                f"Upload timed out after {UPLOAD_TIMEOUT} seconds"
+            ) from None
+        except asyncio.CancelledError:
+            _LOGGER.warning("Upload of %s was cancelled", filename)
+            reader.abort()
+            raise
         finally:
             reader.close()
 
diff --git a/tests/components/backblaze_b2/test_backup.py b/tests/components/backblaze_b2/test_backup.py
index bcf15337bd65..12f5894c49f4 100644
--- a/tests/components/backblaze_b2/test_backup.py
+++ b/tests/components/backblaze_b2/test_backup.py
@@ -1,5 +1,6 @@
 """Backblaze B2 backup agent tests."""
 
+import asyncio
 from collections.abc import AsyncGenerator
 from io import StringIO
 import json
@@ -863,3 +864,94 @@ async def test_metadata_downloads_are_sequential(
     assert response["success"]
     # Verify downloads were sequential (max 1 at a time)
     assert max_concurrent == 1
+
+
+async def test_upload_timeout(
+    hass_client: ClientSessionGenerator,
+    mock_config_entry: MockConfigEntry,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test upload timeout handling."""
+    client = await hass_client()
+
+    mock_file_info = Mock()
+    mock_file_info.delete = Mock()
+
+    with (
+        patch(
+            "homeassistant.components.backup.manager.BackupManager.async_get_backup",
+            return_value=TEST_BACKUP,
+        ),
+        patch(
+            "homeassistant.components.backup.manager.read_backup",
+            return_value=TEST_BACKUP,
+        ),
+        patch("pathlib.Path.open") as mocked_open,
+        patch(
+            "homeassistant.components.backblaze_b2.backup.BackblazeBackupAgent._upload_unbound_stream_sync",
+        ),
+        patch(
+            "homeassistant.components.backblaze_b2.backup.asyncio.wait_for",
+            side_effect=TimeoutError,
+        ),
+        patch.object(
+            BucketSimulator,
+            "get_file_info_by_name",
+            return_value=mock_file_info,
+        ),
+        caplog.at_level(logging.ERROR),
+    ):
+        mocked_open.return_value.read = Mock(side_effect=[b"test", b""])
+        resp = await client.post(
+            f"/api/backup/upload?agent_id={DOMAIN}.{mock_config_entry.entry_id}",
+            data={"file": StringIO("test")},
+        )
+
+    assert resp.status == 201
+    assert any("timed out" in msg for msg in caplog.messages)
+
+
+async def test_upload_cancelled(
+    hass_client: ClientSessionGenerator,
+    mock_config_entry: MockConfigEntry,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test upload cancellation handling."""
+    client = await hass_client()
+
+    mock_file_info = Mock()
+    mock_file_info.delete = Mock()
+
+    with (
+        patch(
+            "homeassistant.components.backup.manager.BackupManager.async_get_backup",
+            return_value=TEST_BACKUP,
+        ),
+        patch(
+            "homeassistant.components.backup.manager.read_backup",
+            return_value=TEST_BACKUP,
+        ),
+        patch("pathlib.Path.open") as mocked_open,
+        patch(
+            "homeassistant.components.backblaze_b2.backup.BackblazeBackupAgent._upload_unbound_stream_sync",
+        ),
+        patch(
+            "homeassistant.components.backblaze_b2.backup.asyncio.wait_for",
+            side_effect=asyncio.CancelledError,
+        ),
+        patch.object(
+            BucketSimulator,
+            "get_file_info_by_name",
+            return_value=mock_file_info,
+        ),
+        caplog.at_level(logging.WARNING),
+    ):
+        mocked_open.return_value.read = Mock(side_effect=[b"test", b""])
+        resp = await client.post(
+            f"/api/backup/upload?agent_id={DOMAIN}.{mock_config_entry.entry_id}",
+            data={"file": StringIO("test")},
+        )
+
+    # CancelledError propagates up and causes a 500 error
+    assert resp.status == 500
+    assert any("cancelled" in msg for msg in caplog.messages)