From 7fada806af1ef922550b2a5bd573846e4a28e85c Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Thu, 14 Jan 2021 10:46:15 -1000
Subject: [PATCH] Downgrade dhcp log message error message when running without
 CAP_NET_RAW (#45157)

---
 homeassistant/components/dhcp/__init__.py |  8 +++++-
 tests/components/dhcp/test_init.py        | 33 ++++++++++++++++++++---
 2 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/homeassistant/components/dhcp/__init__.py b/homeassistant/components/dhcp/__init__.py
index b677325726c..b45add24ee9 100644
--- a/homeassistant/components/dhcp/__init__.py
+++ b/homeassistant/components/dhcp/__init__.py
@@ -2,6 +2,7 @@
 
 import fnmatch
 import logging
+import os
 from threading import Event, Thread
 
 from scapy.error import Scapy_Exception
@@ -70,7 +71,12 @@ class DHCPWatcher(Thread):
                 stop_filter=lambda _: self._stop_event.is_set(),
             )
         except (Scapy_Exception, OSError) as ex:
-            _LOGGER.info("Cannot watch for dhcp packets: %s", ex)
+            if os.geteuid() == 0:
+                _LOGGER.error("Cannot watch for dhcp packets: %s", ex)
+            else:
+                _LOGGER.debug(
+                    "Cannot watch for dhcp packets without root or CAP_NET_RAW: %s", ex
+                )
             return
 
     def handle_dhcp_packet(self, packet):
diff --git a/tests/components/dhcp/test_init.py b/tests/components/dhcp/test_init.py
index d4d22a5f929..04cbc401b08 100644
--- a/tests/components/dhcp/test_init.py
+++ b/tests/components/dhcp/test_init.py
@@ -281,8 +281,8 @@ async def test_setup_and_stop(hass):
     wait_event.set()
 
 
-async def test_setup_fails(hass):
-    """Test we handle sniff setup failing."""
+async def test_setup_fails_as_root(hass, caplog):
+    """Test we handle sniff setup failing as root."""
 
     assert await async_setup_component(
         hass,
@@ -293,10 +293,37 @@ async def test_setup_fails(hass):
 
     wait_event = threading.Event()
 
-    with patch("homeassistant.components.dhcp.sniff", side_effect=Scapy_Exception):
+    with patch("os.geteuid", return_value=0), patch(
+        "homeassistant.components.dhcp.sniff", side_effect=Scapy_Exception
+    ):
         hass.bus.async_fire(EVENT_HOMEASSISTANT_STARTED)
         await hass.async_block_till_done()
 
     hass.bus.async_fire(EVENT_HOMEASSISTANT_STOP)
     await hass.async_block_till_done()
     wait_event.set()
+    assert "Cannot watch for dhcp packets" in caplog.text
+
+
+async def test_setup_fails_non_root(hass, caplog):
+    """Test we handle sniff setup failing as non-root."""
+
+    assert await async_setup_component(
+        hass,
+        dhcp.DOMAIN,
+        {},
+    )
+    await hass.async_block_till_done()
+
+    wait_event = threading.Event()
+
+    with patch("os.geteuid", return_value=10), patch(
+        "homeassistant.components.dhcp.sniff", side_effect=Scapy_Exception
+    ):
+        hass.bus.async_fire(EVENT_HOMEASSISTANT_STARTED)
+        await hass.async_block_till_done()
+
+    hass.bus.async_fire(EVENT_HOMEASSISTANT_STOP)
+    await hass.async_block_till_done()
+    wait_event.set()
+    assert "Cannot watch for dhcp packets without root or CAP_NET_RAW" in caplog.text