From ff1bbba92aad261df1ebd8fd8cc189c104e113b0 Mon Sep 17 00:00:00 2001 From: Antoine Pitrou Date: Sat, 18 Dec 2010 18:04:38 +0000 Subject: [PATCH] Merged revisions 87373,87381 via svnmerge from svn+ssh://pythondev@svn.python.org/python/branches/py3k MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ........ r87373 | senthil.kumaran | 2010-12-18 17:55:23 +0100 (sam., 18 déc. 2010) | 3 lines Fix Issue6791 - Limit the HTTP header readline with _MAXLENGTH. Patch by Antoine Pitrou ........ r87381 | antoine.pitrou | 2010-12-18 18:59:18 +0100 (sam., 18 déc. 2010) | 3 lines NEWS entry for r87373 ........ --- Lib/http/client.py | 29 ++++++++++++++++++++++++----- Lib/http/server.py | 8 ++++++-- Lib/test/test_httplib.py | 28 ++++++++++++++++++++++++++++ Lib/test/test_httpservers.py | 7 +++++++ Misc/NEWS | 3 +++ 5 files changed, 68 insertions(+), 7 deletions(-) diff --git a/Lib/http/client.py b/Lib/http/client.py index bd092c215ef..296dafb2c0d 100644 --- a/Lib/http/client.py +++ b/Lib/http/client.py @@ -203,6 +203,9 @@ responses = { # maximal amount of data to read at one time in _safe_read MAXAMOUNT = 1048576 +# maximal line length when calling readline(). +_MAXLINE = 65536 + class HTTPMessage(email.message.Message): # XXX The only usage of this method is in # http.server.CGIHTTPRequestHandler. Maybe move the code there so @@ -245,7 +248,9 @@ def parse_headers(fp, _class=HTTPMessage): """ headers = [] while True: - line = fp.readline() + line = fp.readline(_MAXLINE + 1) + if len(line) > _MAXLINE: + raise LineTooLong("header line") headers.append(line) if line in (b'\r\n', b'\n', b''): break @@ -349,7 +354,10 @@ class HTTPResponse(io.RawIOBase): break # skip the header from the 100 response while True: - skip = self.fp.readline().strip() + skip = self.fp.readline(_MAXLINE + 1) + if len(skip) > _MAXLINE: + raise LineTooLong("header line") + skip = skip.strip() if not skip: break if self.debuglevel > 0: @@ -525,7 +533,9 @@ class HTTPResponse(io.RawIOBase): value = [] while True: if chunk_left is None: - line = self.fp.readline() + line = self.fp.readline(_MAXLINE + 1) + if len(line) > _MAXLINE: + raise LineTooLong("chunk size") i = line.find(b";") if i >= 0: line = line[:i] # strip chunk-extensions @@ -560,7 +570,9 @@ class HTTPResponse(io.RawIOBase): # read and discard trailer up to the CRLF terminator ### note: we shouldn't have any trailers! while True: - line = self.fp.readline() + line = self.fp.readline(_MAXLINE + 1) + if len(line) > _MAXLINE: + raise LineTooLong("trailer line") if not line: # a vanishingly small number of sites EOF without # sending the trailer @@ -703,7 +715,9 @@ class HTTPConnection: raise socket.error("Tunnel connection failed: %d %s" % (code, message.strip())) while True: - line = response.fp.readline() + line = response.fp.readline(_MAXLINE + 1) + if len(line) > _MAXLINE: + raise LineTooLong("header line") if line == b'\r\n': break @@ -1133,6 +1147,11 @@ class BadStatusLine(HTTPException): self.args = line, self.line = line +class LineTooLong(HTTPException): + def __init__(self, line_type): + HTTPException.__init__(self, "got more than %d bytes when reading %s" + % (_MAXLINE, line_type)) + # for backwards compatibility error = HTTPException diff --git a/Lib/http/server.py b/Lib/http/server.py index 5ac6c0d204e..8de604a739e 100644 --- a/Lib/http/server.py +++ b/Lib/http/server.py @@ -314,8 +314,12 @@ class BaseHTTPRequestHandler(socketserver.StreamRequestHandler): self.command, self.path, self.request_version = command, path, version # Examine the headers and look for a Connection directive. - self.headers = http.client.parse_headers(self.rfile, - _class=self.MessageClass) + try: + self.headers = http.client.parse_headers(self.rfile, + _class=self.MessageClass) + except http.client.LineTooLong: + self.send_error(400, "Line too long") + return False conntype = self.headers.get('Connection', "") if conntype.lower() == 'close': diff --git a/Lib/test/test_httplib.py b/Lib/test/test_httplib.py index 4c02d909bc8..43985a66529 100644 --- a/Lib/test/test_httplib.py +++ b/Lib/test/test_httplib.py @@ -303,6 +303,34 @@ class BasicTest(TestCase): self.assertEqual("Basic realm=\"example\"", resp.getheader("www-authenticate")) + # Test lines overflowing the max line size (_MAXLINE in http.client) + + def test_overflowing_status_line(self): + self.skipTest("disabled for HTTP 0.9 support") + body = "HTTP/1.1 200 Ok" + "k" * 65536 + "\r\n" + resp = client.HTTPResponse(FakeSocket(body)) + self.assertRaises((client.LineTooLong, client.BadStatusLine), resp.begin) + + def test_overflowing_header_line(self): + body = ( + 'HTTP/1.1 200 OK\r\n' + 'X-Foo: bar' + 'r' * 65536 + '\r\n\r\n' + ) + resp = client.HTTPResponse(FakeSocket(body)) + self.assertRaises(client.LineTooLong, resp.begin) + + def test_overflowing_chunked_line(self): + body = ( + 'HTTP/1.1 200 OK\r\n' + 'Transfer-Encoding: chunked\r\n\r\n' + + '0' * 65536 + 'a\r\n' + 'hello world\r\n' + '0\r\n' + ) + resp = client.HTTPResponse(FakeSocket(body)) + resp.begin() + self.assertRaises(client.LineTooLong, resp.read) + class OfflineTest(TestCase): def test_responses(self): self.assertEqual(client.responses[client.NOT_FOUND], "Not Found") diff --git a/Lib/test/test_httpservers.py b/Lib/test/test_httpservers.py index 622827938ed..4f1ecff4a91 100644 --- a/Lib/test/test_httpservers.py +++ b/Lib/test/test_httpservers.py @@ -144,6 +144,13 @@ class BaseHTTPRequestHandlerTestCase(unittest.TestCase): self.assertEqual(result[0], b'HTTP/1.1 414 Request-URI Too Long\r\n') self.assertFalse(self.handler.get_called) + def test_header_length(self): + # Issue #6791: same for headers + result = self.send_typical_request( + b'GET / HTTP/1.1\r\nX-Foo: bar' + b'r' * 65537 + b'\r\n\r\n') + self.assertEqual(result[0], b'HTTP/1.1 400 Line too long\r\n') + self.assertFalse(self.handler.get_called) + class BaseHTTPServerTestCase(BaseTestCase): class request_handler(NoLogRequestHandler, BaseHTTPRequestHandler): diff --git a/Misc/NEWS b/Misc/NEWS index def99aad1a8..0ff81decb7f 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -24,6 +24,9 @@ Core and Builtins Library ------- +- Issue #6791: Limit header line length (to 65535 bytes) in http.client + and http.server, to avoid denial of services from the other party. + - Issue #10404: Use ctl-button-1 on OSX for the context menu in Idle. - Issue #4188: Avoid creating dummy thread objects when logging operations