From: Michael Tremer <michael.tremer@ipfire.org>
Date: Fri, 2 Jan 2026 14:11:46 +0000 (+0000)
Subject: sources: Rework the hosts file parser
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a286913c45fc70e58662e2a286c27cdcbdd6cbf1;p=dbl.git

sources: Rework the hosts file parser

Some sources use tabs to split and since we don't want to have a large
list of IP addresses, we simply check if we now have a format where we
list an IP address and something else.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---

diff --git a/src/dnsbl/sources.py b/src/dnsbl/sources.py
index 5705daf..b58c311 100644
--- a/src/dnsbl/sources.py
+++ b/src/dnsbl/sources.py
@@ -24,6 +24,7 @@ import enum
 import gzip
 import httpx
 import idna
+import ipaddress
 import io
 import itertools
 import logging
@@ -39,12 +40,6 @@ from .i18n import _
 # Setup logging
 log = logging.getLogger(__name__)
 
-HOST_PREFIXES = set((
-	"0.0.0.0 ",
-	"127.0.0.1 ",
-	"::1 ",
-))
-
 IGNORED_DOMAINS = set((
 	"localhost",
 ))
@@ -400,7 +395,7 @@ class Source(sqlmodel.SQLModel, database.BackendMixin, table=True):
 			return Format.ADBLOCKPLUS
 
 		# Is this a hosts file?
-		elif any(line.startswith(prefix) for prefix in HOST_PREFIXES):
+		elif self._detect_format_hosts(line):
 			return Format.HOSTS
 
 		# Check for a plain FQDN
@@ -410,6 +405,19 @@ class Source(sqlmodel.SQLModel, database.BackendMixin, table=True):
 		# The format is (still?) unknown
 		return None
 
+	def _detect_format_hosts(self, line):
+		"""
+			Checks if the line is in hosts format
+		"""
+		domain = self._process_hosts(line)
+
+		# If we could parse the domain, this looks like the hosts format
+		if domain:
+			return True
+
+		# We could not parse anything
+		return False
+
 	def _process_adblockplus(self, line):
 		"""
 			Parse the domain from the AdBlockPlus format
@@ -427,12 +435,23 @@ class Source(sqlmodel.SQLModel, database.BackendMixin, table=True):
 		"""
 			Parses a line of a hosts file.
 		"""
-		for prefix in HOST_PREFIXES:
-			if line.startswith(prefix):
-				return line.removeprefix(prefix)
+		try:
+			address, domain = line.split()
 
-		# If none of the prefixes matched, we return the entire line
-		return line
+		# If we could not split the line by two tokens, it is not a hosts file
+		except ValueError as e:
+			return
+
+		# Check if we can parse the IP address
+		try:
+			ipaddress.ip_address(address)
+
+		# If the line is not prefixed with an IP address, we cannot continue
+		except ValueError as e:
+			return
+
+		# We have a valid IP address and therefore can return the domain
+		return domain
 
 	def _process_plain(self, line):
 		"""