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[90.182.211.1]) by smtp.gmail.com with UTF8SMTPSA id 5b1f17b1804b1-4a17f486b6fsm115877215e9.1.2026.10.08.08.04.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 08 Oct 2026 08:04:56 -0700 (PDT) From: =?utf-8?q?Piotr_Buli=C5=84ski?= To: yocto-patches@lists.yoctoproject.org Cc: =?utf-8?q?Piotr_Buli=C5=84ski?= Subject: [error-report-web][PATCH 2/3] Add link back validator and use it in the parser. Date: Thu, 8 Oct 2026 17:04:45 +0200 Message-ID: <20261008150446.74259-2-piotr@qbee.io> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20261008150446.74259-1-piotr@qbee.io> References: <20261008150446.74259-1-piotr@qbee.io> MIME-Version: 1.0 List-Id: X-Webhook-Received: from 45-33-107-173.ip.linodeusercontent.com [45.33.107.173] by aws-us-west-2-korg-lkml-1.web.codeaurora.org with HTTPS for ; Thu, 08 Oct 2026 15:05:11 -0000 X-Groupsio-URL: https://lists.yoctoproject.org/g/yocto-patches/message/5000 This will prevent invalid URL (non-http(s)) from being recorded. Signed-off-by: Piotr Buliński --- Post/parser.py | 3 +- Post/test.py | 84 ++++++++++++++++++++++++++++++++++++++++++++++ Post/validators.py | 42 +++++++++++++++++++++++ 3 files changed, 128 insertions(+), 1 deletion(-) create mode 100644 Post/validators.py diff --git a/Post/parser.py b/Post/parser.py index 08f471d..b6740d0 100644 --- a/Post/parser.py +++ b/Post/parser.py @@ -11,6 +11,7 @@ import json, re import bleach from Post.models import Build, BuildFailure, ErrorType +from Post.validators import clean_link_back from django.conf import settings from django.utils import timezone from django.urls import reverse @@ -48,7 +49,7 @@ class Parser: b.DISTRO = str(jsondata['distro']) b.NAME = str(jsondata['username']) b.EMAIL = str(jsondata['email']) - b.LINK_BACK = jsondata.get("link_back", None) + b.LINK_BACK = clean_link_back(jsondata.get("link_back", None)) b.ERROR_TYPE = jsondata.get("error_type", ErrorType.RECIPE) # Extract the branch and commit diff --git a/Post/test.py b/Post/test.py index 15aa4be..0705f3c 100755 --- a/Post/test.py +++ b/Post/test.py @@ -4,6 +4,7 @@ import json import re from django.test import Client, override_settings from Post.models import BuildFailure, Build +from Post.validators import clean_link_back #Delete the data between tests def data_runner (func): @@ -246,3 +247,86 @@ class SimpleTest(unittest.TestCase): response = self.client.get("/Errors/Details/9898989898/") self.assertEqual(response.status_code, 200) + + +class LinkBackValidatorTest(unittest.TestCase): + + def test_allows_http(self): + self.assertEqual(clean_link_back("http://example.com/build/1"), + "http://example.com/build/1") + + def test_allows_https(self): + self.assertEqual(clean_link_back("https://example.com/build/1"), + "https://example.com/build/1") + + def test_rejects_javascript(self): + self.assertIsNone( + clean_link_back("javascript:alert(document.domain)//PROBE")) + + def test_rejects_data(self): + self.assertIsNone( + clean_link_back("data:text/html,")) + + def test_rejects_vbscript(self): + self.assertIsNone(clean_link_back("vbscript:msgbox(1)")) + + def test_rejects_scheme_relative(self): + self.assertIsNone(clean_link_back("//evil.example.com/x")) + + def test_rejects_schemeless(self): + self.assertIsNone(clean_link_back("example.com/build/1")) + + def test_rejects_control_char_obfuscation(self): + self.assertIsNone(clean_link_back("java\tscript:alert(1)")) + + def test_rejects_leading_whitespace(self): + self.assertIsNone(clean_link_back(" javascript:alert(1)")) + + def test_rejects_missing_host(self): + self.assertIsNone(clean_link_back("http:///path")) + + def test_rejects_none_empty_and_non_string(self): + self.assertIsNone(clean_link_back(None)) + self.assertIsNone(clean_link_back("")) + self.assertIsNone(clean_link_back(" ")) + self.assertIsNone(clean_link_back(123)) + + +class LinkBackSubmissionTest(unittest.TestCase): + + def setUp(self): + # The test client submits with HTTP_HOST="testhost"; allow it here. + override = override_settings(ALLOWED_HOSTS=["testhost"]) + override.enable() + self.addCleanup(override.disable) + self.client = Client(HTTP_HOST="testhost") + # Start from a clean slate; other unittest.TestCase tests commit rows. + Build.objects.all().delete() + BuildFailure.objects.all().delete() + with open("test-data/test-payload.json") as f: + self.base_payload = json.loads(f.read()) + + def tearDown(self): + Build.objects.all().delete() + BuildFailure.objects.all().delete() + + def _submit(self, link_back): + payload = dict(self.base_payload) + payload['link_back'] = link_back + data = urllib.parse.urlencode({'data': json.dumps(payload)}) + response = self.client.post("/ClientPost/", data, "application/json") + self.assertEqual(response.status_code, 200, response.content) + return BuildFailure.objects.get() + + def test_javascript_link_back_is_blanked(self): + bf = self._submit("javascript:alert(document.domain)//PROBE") + self.assertIsNone(bf.BUILD.LINK_BACK) + + response = self.client.get("/Errors/Details/%d/" % bf.id) + self.assertEqual(response.status_code, 200) + self.assertNotIn(b'href="javascript:', response.content) + + def test_http_link_back_is_preserved(self): + bf = self._submit("http://example.com/build/42") + self.assertEqual(bf.BUILD.LINK_BACK, "http://example.com/build/42") + diff --git a/Post/validators.py b/Post/validators.py new file mode 100644 index 0000000..c549664 --- /dev/null +++ b/Post/validators.py @@ -0,0 +1,42 @@ +# SPDX-License-Identifier: MIT +# +# error-reporting-tool - link-back URL validation +# +# Licensed under the MIT license, see COPYING.MIT for details + +import re +from urllib.parse import urlparse + +# Only absolute http(s) URLs are allowed as a "link back". Everything else +# (javascript:, data:, vbscript:, scheme-relative "//host" or schemeless +# values) is rejected so it can never be rendered verbatim into an href. +ALLOWED_LINK_BACK_SCHEMES = ("http", "https") + +# Control characters are used to obfuscate schemes, e.g. "java\tscript:". +_CONTROL_CHARS = re.compile(r"[\x00-\x1f\x7f]") + + +def clean_link_back(value): + """Return a safe link-back URL, or None if the value is not acceptable.""" + if not isinstance(value, str): + return None + + value = value.strip() + if not value: + return None + + if _CONTROL_CHARS.search(value): + return None + + try: + parsed = urlparse(value) + except ValueError: + return None + + if parsed.scheme.lower() not in ALLOWED_LINK_BACK_SCHEMES: + return None + + if not parsed.netloc: + return None + + return value