From 3331e2aecdbf575dd60abef4df79c52d78610a83 Mon Sep 17 00:00:00 2001 From: Bruce Merry Date: Thu, 28 Jun 2018 16:38:42 +0200 Subject: [PATCH 1/2] Strip Authorization header whenever root URL changes Previously the header was stripped only if the hostname changed, but in an https -> http redirect that can leak the credentials on the wire (#4716). Based on with RFC 7235 section 2.2, the header is now stripped if the "canonical root URL" (scheme+authority) has changed, by checking scheme, hostname and port. --- requests/sessions.py | 4 +++- tests/test_requests.py | 12 +++++++++++- 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/requests/sessions.py b/requests/sessions.py index dd525e2ac9..702cd73ecb 100644 --- a/requests/sessions.py +++ b/requests/sessions.py @@ -242,7 +242,9 @@ def rebuild_auth(self, prepared_request, response): original_parsed = urlparse(response.request.url) redirect_parsed = urlparse(url) - if (original_parsed.hostname != redirect_parsed.hostname): + if (original_parsed.hostname != redirect_parsed.hostname + or original_parsed.port != redirect_parsed.port + or original_parsed.scheme != redirect_parsed.scheme): del headers['Authorization'] # .netrc might have more auth for us on our new host. diff --git a/tests/test_requests.py b/tests/test_requests.py index fd04ad2705..b05d8ebb29 100644 --- a/tests/test_requests.py +++ b/tests/test_requests.py @@ -1581,7 +1581,17 @@ def test_auth_is_stripped_on_redirect_off_host(self, httpbin): auth=('user', 'pass'), ) assert r.history[0].request.headers['Authorization'] - assert not r.request.headers.get('Authorization', '') + assert 'Authorization' not in r.request.headers + + def test_auth_is_stripped_on_scheme_redirect(self, httpbin, httpbin_secure, httpbin_ca_bundle): + r = requests.get( + httpbin_secure('redirect-to'), + params={'url': httpbin('get')}, + auth=('user', 'pass'), + verify=httpbin_ca_bundle + ) + assert r.history[0].request.headers['Authorization'] + assert 'Authorization' not in r.request.headers def test_auth_is_retained_for_redirect_on_host(self, httpbin): r = requests.get(httpbin('redirect/1'), auth=('user', 'pass')) From 857e9b7ac20c3accf4cc328f594aecb8b6a644a6 Mon Sep 17 00:00:00 2001 From: Bruce Merry Date: Tue, 14 Aug 2018 13:30:43 +0200 Subject: [PATCH 2/2] Rework authorization stripping logic as discussed The exception for http->https upgrade now requires the standard HTTP(S) ports to be used, either implicitly (no port specified) or explicitly. --- requests/sessions.py | 26 ++++++++++++++++++-------- tests/test_requests.py | 33 ++++++++++++++++++++++----------- 2 files changed, 40 insertions(+), 19 deletions(-) diff --git a/requests/sessions.py b/requests/sessions.py index 702cd73ecb..27d0e9717d 100644 --- a/requests/sessions.py +++ b/requests/sessions.py @@ -115,6 +115,22 @@ def get_redirect_target(self, resp): return to_native_string(location, 'utf8') return None + def should_strip_auth(self, old_url, new_url): + """Decide whether Authorization header should be removed when redirecting""" + old_parsed = urlparse(old_url) + new_parsed = urlparse(new_url) + if old_parsed.hostname != new_parsed.hostname: + return True + # Special case: allow http -> https redirect when using the standard + # ports. This isn't specified by RFC 7235, but is kept to avoid + # breaking backwards compatibility with older versions of requests + # that allowed any redirects on the same host. + if (old_parsed.scheme == 'http' and old_parsed.port in (80, None) + and new_parsed.scheme == 'https' and new_parsed.port in (443, None)): + return False + # Standard case: root URI must match + return old_parsed.port != new_parsed.port or old_parsed.scheme != new_parsed.scheme + def resolve_redirects(self, resp, req, stream=False, timeout=None, verify=True, cert=None, proxies=None, yield_requests=False, **adapter_kwargs): """Receives a Response. Returns a generator of Responses or Requests.""" @@ -236,16 +252,10 @@ def rebuild_auth(self, prepared_request, response): headers = prepared_request.headers url = prepared_request.url - if 'Authorization' in headers: + if 'Authorization' in headers and self.should_strip_auth(response.request.url, url): # If we get redirected to a new host, we should strip out any # authentication headers. - original_parsed = urlparse(response.request.url) - redirect_parsed = urlparse(url) - - if (original_parsed.hostname != redirect_parsed.hostname - or original_parsed.port != redirect_parsed.port - or original_parsed.scheme != redirect_parsed.scheme): - del headers['Authorization'] + del headers['Authorization'] # .netrc might have more auth for us on our new host. new_auth = get_netrc_auth(url) if self.trust_env else None diff --git a/tests/test_requests.py b/tests/test_requests.py index b05d8ebb29..660437988a 100644 --- a/tests/test_requests.py +++ b/tests/test_requests.py @@ -1573,17 +1573,7 @@ def test_nonhttp_schemes_dont_check_URLs(self): preq = req.prepare() assert test_url == preq.url - @pytest.mark.xfail(raises=ConnectionError) - def test_auth_is_stripped_on_redirect_off_host(self, httpbin): - r = requests.get( - httpbin('redirect-to'), - params={'url': 'http://www.google.co.uk'}, - auth=('user', 'pass'), - ) - assert r.history[0].request.headers['Authorization'] - assert 'Authorization' not in r.request.headers - - def test_auth_is_stripped_on_scheme_redirect(self, httpbin, httpbin_secure, httpbin_ca_bundle): + def test_auth_is_stripped_on_http_downgrade(self, httpbin, httpbin_secure, httpbin_ca_bundle): r = requests.get( httpbin_secure('redirect-to'), params={'url': httpbin('get')}, @@ -1600,6 +1590,27 @@ def test_auth_is_retained_for_redirect_on_host(self, httpbin): assert h1 == h2 + def test_should_strip_auth_host_change(self): + s = requests.Session() + assert s.should_strip_auth('http://example.com/foo', 'http://another.example.com/') + + def test_should_strip_auth_http_downgrade(self): + s = requests.Session() + assert s.should_strip_auth('https://example.com/foo', 'http://example.com/bar') + + def test_should_strip_auth_https_upgrade(self): + s = requests.Session() + assert not s.should_strip_auth('http://example.com/foo', 'https://example.com/bar') + assert not s.should_strip_auth('http://example.com:80/foo', 'https://example.com/bar') + assert not s.should_strip_auth('http://example.com/foo', 'https://example.com:443/bar') + # Non-standard ports should trigger stripping + assert s.should_strip_auth('http://example.com:8080/foo', 'https://example.com/bar') + assert s.should_strip_auth('http://example.com/foo', 'https://example.com:8443/bar') + + def test_should_strip_auth_port_change(self): + s = requests.Session() + assert s.should_strip_auth('http://example.com:1234/foo', 'https://example.com:4321/bar') + def test_manual_redirect_with_partial_body_read(self, httpbin): s = requests.Session() r1 = s.get(httpbin('redirect/2'), allow_redirects=False, stream=True)