tests/gnrc_tcp: provide regression tests for fixed issues

tests/gnrc_tcp/README.md

@@ -18,6 +18,10 @@ in the tests directory.
     This test covers receiving of a byte stream from the host system. The received data is
     causing window opening and closing as well as data transmission over multiple packets.
 
+5) 05-garbage-pkts.py
+    This test mostly is a regression test for issues that were found through fuzzing. It uses
+    `scapy` to interact with the node.
+
 Setup
 ==========
 The test requires a tap-device setup. This can be achieved by running 'dist/tools/tapsetup/tapsetup'
@@ -31,4 +35,4 @@ Usage
     make BOARD=<BOARD_NAME> all flash
     sudo make BOARD=<BOARD_NAME> test
 
-'sudo' is only required if the board is not native, due to ethos usage.
+'sudo' is required due to ethos and raw socket usage.

tests/gnrc_tcp/tests/05-garbage-pkts.py

@@ -0,0 +1,146 @@
+#!/usr/bin/env python3
+
+# Copyright (C) 2019 Freie Universität Berlin
+#
+# This file is subject to the terms and conditions of the GNU Lesser
+# General Public License v2.1. See the file LICENSE in the top level
+# directory for more details.
+
+import base64
+import os
+import socket
+import sys
+
+from scapy.all import Ether, IPv6, TCP, raw, \
+                      sendp
+from testrunner import run
+
+from shared_func import sudo_guard, get_host_tap_device, get_host_ll_addr, \
+                        get_riot_if_id, get_riot_l2_addr, get_riot_ll_addr, \
+                        generate_port_number, verify_pktbuf_empty
+
+
+def testfunc(func):
+    def runner(child):
+        tap = get_host_tap_device()
+        host_ll = get_host_ll_addr(tap)
+        dst_if = get_riot_if_id(child)
+        dst_ll = get_riot_ll_addr(child)
+        dst_l2 = get_riot_l2_addr(child)
+        port = generate_port_number()
+
+        # Setup RIOT Node wait for incoming connections from host system
+        child.sendline('gnrc_tcp_tcb_init')
+        child.expect_exact('gnrc_tcp_tcb_init: argc=1, argv[0] = gnrc_tcp_tcb_init')
+        child.sendline('gnrc_tcp_open_passive AF_INET6 {}'.format(port))
+        child.expect(r'gnrc_tcp_open_passive: argc=3, '
+                     r'argv\[0\] = gnrc_tcp_open_passive, '
+                     r'argv\[1\] = AF_INET6, argv\[2\] = (\d+)')
+        assert int(child.match.group(1)) == port
+
+        try:
+            print("- {} ".format(func.__name__), end="")
+            if child.logfile == sys.stdout:
+                func(child, tap, host_ll, dst_if, dst_l2, dst_ll, port)
+                print("")
+            else:
+                try:
+                    func(child, tap, host_ll, dst_if, dst_l2, dst_ll, port)
+                    print("SUCCESS")
+                except Exception as e:
+                    print("FAILED")
+                    raise e
+        finally:
+            child.sendline('gnrc_tcp_close')
+
+    return runner
+
+
+@testfunc
+def test_short_payload(child, src_if, src_ll, dst_if, dst_l2, dst_ll, dst_port):
+    # see https://github.com/RIOT-OS/RIOT/issues/11999
+    with socket.socket(socket.AF_INET6, socket.SOCK_STREAM) as sock:
+        sock.settimeout(child.timeout)
+        addr_info = socket.getaddrinfo(dst_ll + '%' + src_if, dst_port,
+                                       type=socket.SOCK_STREAM)
+        sock.connect(addr_info[0][-1])
+        child.expect_exact('gnrc_tcp_open_passive: returns 0')
+        child.sendline('gnrc_tcp_recv 1000000 1')
+        child.expect_exact('gnrc_tcp_recv: argc=3, '
+                           'argv[0] = gnrc_tcp_recv, '
+                           'argv[1] = 1000000, argv[2] = 1')
+        assert 1 == sock.send(b"f")
+        child.expect_exact('gnrc_tcp_recv: received 1', timeout=20)
+    verify_pktbuf_empty(child)
+
+
+@testfunc
+def test_short_header(child, src_if, src_ll, dst_if, dst_l2, dst_ll, dst_port):
+    # see https://github.com/RIOT-OS/RIOT/issues/12086
+    tcp_hdr = TCP(dport=dst_port, flags="S", sport=2342, seq=1, dataofs=6)
+    # shorten header
+    tcp_hdr = raw(tcp_hdr)[:-2]
+    sendp(Ether(dst=dst_l2) / IPv6(src=src_ll, dst=dst_ll) / tcp_hdr,
+          iface=src_if, verbose=0)
+
+    # let server command return to later check packet buffer
+    with socket.socket(socket.AF_INET6, socket.SOCK_STREAM) as sock:
+        sock.settimeout(child.timeout)
+        addr_info = socket.getaddrinfo(dst_ll + '%' + src_if, dst_port,
+                                       type=socket.SOCK_STREAM)
+        sock.connect(addr_info[0][-1])
+        child.expect_exact('gnrc_tcp_open_passive: returns 0')
+    verify_pktbuf_empty(child)
+
+
+@testfunc
+def test_send_ack_instead_of_syn(child, src_if, src_ll,
+                                 dst_if, dst_l2, dst_ll, dst_port):
+    # see https://github.com/RIOT-OS/RIOT/pull/12001
+    provided_data = base64.b64decode("rwsQf2pekYLaU+exUBBwgPDKAAA=")
+    tcp_hdr = TCP(provided_data)
+    assert provided_data == raw(tcp_hdr)
+    # set destination port to application specific port
+    tcp_hdr.dport = dst_port
+    sendp(Ether(dst=dst_l2) / IPv6(src=src_ll, dst=dst_ll) / tcp_hdr,
+          iface=src_if, verbose=0, count=1000)
+
+    # check if server actually still works
+    with socket.socket(socket.AF_INET6, socket.SOCK_STREAM) as sock:
+        sock.settimeout(child.timeout)
+        addr_info = socket.getaddrinfo(dst_ll + '%' + src_if, dst_port,
+                                       type=socket.SOCK_STREAM)
+        sock.connect(addr_info[0][-1])
+        child.expect_exact('gnrc_tcp_open_passive: returns 0')
+    verify_pktbuf_empty(child)
+
+
+@testfunc
+def test_option_parsing_term(child, src_if, src_ll,
+                             dst_if, dst_l2, dst_ll, dst_port):
+    # see https://github.com/RIOT-OS/RIOT/issues/12086
+    tcp_hdr = TCP(dport=dst_port, flags="S", sport=2342, seq=1, dataofs=6)
+    sendp(Ether(dst=dst_l2) / IPv6(src=src_ll, dst=dst_ll) / tcp_hdr /
+          b"\x50\x00\x00\x00", iface=src_if, verbose=0)
+
+    # check if server actually still works
+    with socket.socket(socket.AF_INET6, socket.SOCK_STREAM) as sock:
+        sock.settimeout(child.timeout)
+        addr_info = socket.getaddrinfo(dst_ll + '%' + src_if, dst_port,
+                                       type=socket.SOCK_STREAM)
+        sock.connect(addr_info[0][-1])
+        child.expect_exact('gnrc_tcp_open_passive: returns 0')
+    verify_pktbuf_empty(child)
+
+
+if __name__ == "__main__":
+    sudo_guard(uses_scapy=True)
+    script = sys.modules[__name__]
+    tests = [getattr(script, t) for t in script.__dict__
+             if type(getattr(script, t)).__name__ == "function"
+             and t.startswith("test_")]
+    for test in tests:
+        res = run(test, timeout=10, echo=False)
+        if res != 0:
+            sys.exit(res)
+    print(os.path.basename(sys.argv[0]) + ": success\n")