From 9b4d3280e172063a6563d9e72a75b500442ed9b9 Mon Sep 17 00:00:00 2001 From: Kevin Krakauer Date: Fri, 12 Jul 2019 18:08:03 -0700 Subject: Add IPPROTO_RAW, which allows raw sockets to write IP headers. iptables also relies on IPPROTO_RAW in a way. It opens such a socket to manipulate the kernel's tables, but it doesn't actually use any of the functionality. Blegh. PiperOrigin-RevId: 257903078 --- test/syscalls/BUILD | 4 + test/syscalls/linux/BUILD | 18 ++ test/syscalls/linux/raw_socket_hdrincl.cc | 408 ++++++++++++++++++++++++++++++ 3 files changed, 430 insertions(+) create mode 100644 test/syscalls/linux/raw_socket_hdrincl.cc (limited to 'test/syscalls') diff --git a/test/syscalls/BUILD b/test/syscalls/BUILD index 4ac511740..c54d90a1c 100644 --- a/test/syscalls/BUILD +++ b/test/syscalls/BUILD @@ -319,6 +319,10 @@ syscall_test( test = "//test/syscalls/linux:pwrite64_test", ) +syscall_test(test = "//test/syscalls/linux:raw_socket_hdrincl_test") + +syscall_test(test = "//test/syscalls/linux:raw_socket_icmp_test") + syscall_test(test = "//test/syscalls/linux:raw_socket_ipv4_test") syscall_test( diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD index 4735284ba..c5a368463 100644 --- a/test/syscalls/linux/BUILD +++ b/test/syscalls/linux/BUILD @@ -1561,6 +1561,24 @@ cc_binary( ], ) +cc_binary( + name = "raw_socket_hdrincl_test", + testonly = 1, + srcs = ["raw_socket_hdrincl.cc"], + linkstatic = 1, + deps = [ + ":socket_test_util", + ":unix_domain_socket_test_util", + "//test/util:capability_util", + "//test/util:file_descriptor", + "//test/util:test_main", + "//test/util:test_util", + "@com_google_absl//absl/base:core_headers", + "@com_google_absl//absl/base:endian", + "@com_google_googletest//:gtest", + ], +) + cc_binary( name = "raw_socket_ipv4_test", testonly = 1, diff --git a/test/syscalls/linux/raw_socket_hdrincl.cc b/test/syscalls/linux/raw_socket_hdrincl.cc new file mode 100644 index 000000000..a070817eb --- /dev/null +++ b/test/syscalls/linux/raw_socket_hdrincl.cc @@ -0,0 +1,408 @@ +// Copyright 2019 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "gtest/gtest.h" +#include "absl/base/internal/endian.h" +#include "test/syscalls/linux/socket_test_util.h" +#include "test/syscalls/linux/unix_domain_socket_test_util.h" +#include "test/util/capability_util.h" +#include "test/util/file_descriptor.h" +#include "test/util/test_util.h" + +namespace gvisor { +namespace testing { + +namespace { + +// Tests for IPPROTO_RAW raw sockets, which implies IP_HDRINCL. +class RawHDRINCL : public ::testing::Test { + protected: + // Creates a socket to be used in tests. + void SetUp() override; + + // Closes the socket created by SetUp(). + void TearDown() override; + + // Returns a valid looback IP header with no payload. + struct iphdr LoopbackHeader(); + + // Fills in buf with an IP header, UDP header, and payload. Returns false if + // buf_size isn't large enough to hold everything. + bool FillPacket(char* buf, size_t buf_size, int port, const char* payload, + uint16_t payload_size); + + // The socket used for both reading and writing. + int socket_; + + // The loopback address. + struct sockaddr_in addr_; +}; + +void RawHDRINCL::SetUp() { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + ASSERT_THAT(socket_ = socket(AF_INET, SOCK_RAW, IPPROTO_RAW), + SyscallSucceeds()); + + addr_ = {}; + + addr_.sin_port = IPPROTO_IP; + addr_.sin_addr.s_addr = htonl(INADDR_LOOPBACK); + addr_.sin_family = AF_INET; +} + +void RawHDRINCL::TearDown() { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + EXPECT_THAT(close(socket_), SyscallSucceeds()); +} + +struct iphdr RawHDRINCL::LoopbackHeader() { + struct iphdr hdr = {}; + hdr.ihl = 5; + hdr.version = 4; + hdr.tos = 0; + hdr.tot_len = absl::gbswap_16(sizeof(hdr)); + hdr.id = 0; + hdr.frag_off = 0; + hdr.ttl = 7; + hdr.protocol = 1; + hdr.daddr = htonl(INADDR_LOOPBACK); + // hdr.check is set by the network stack. + // hdr.tot_len is set by the network stack. + // hdr.saddr is set by the network stack. + return hdr; +} + +bool RawHDRINCL::FillPacket(char* buf, size_t buf_size, int port, + const char* payload, uint16_t payload_size) { + if (buf_size < sizeof(struct iphdr) + sizeof(struct udphdr) + payload_size) { + return false; + } + + struct iphdr ip = LoopbackHeader(); + ip.protocol = IPPROTO_UDP; + + struct udphdr udp = {}; + udp.source = absl::gbswap_16(port); + udp.dest = absl::gbswap_16(port); + udp.len = absl::gbswap_16(sizeof(udp) + payload_size); + udp.check = 0; + + memcpy(buf, reinterpret_cast(&ip), sizeof(ip)); + memcpy(buf + sizeof(ip), reinterpret_cast(&udp), sizeof(udp)); + memcpy(buf + sizeof(ip) + sizeof(udp), payload, payload_size); + + return true; +} + +// We should be able to create multiple IPPROTO_RAW sockets. RawHDRINCL::Setup +// creates the first one, so we only have to create one more here. +TEST_F(RawHDRINCL, MultipleCreation) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + int s2; + ASSERT_THAT(s2 = socket(AF_INET, SOCK_RAW, IPPROTO_RAW), SyscallSucceeds()); + + ASSERT_THAT(close(s2), SyscallSucceeds()); +} + +// Test that shutting down an unconnected socket fails. +TEST_F(RawHDRINCL, FailShutdownWithoutConnect) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + ASSERT_THAT(shutdown(socket_, SHUT_WR), SyscallFailsWithErrno(ENOTCONN)); + ASSERT_THAT(shutdown(socket_, SHUT_RD), SyscallFailsWithErrno(ENOTCONN)); +} + +// Test that listen() fails. +TEST_F(RawHDRINCL, FailListen) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + ASSERT_THAT(listen(socket_, 1), SyscallFailsWithErrno(ENOTSUP)); +} + +// Test that accept() fails. +TEST_F(RawHDRINCL, FailAccept) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + struct sockaddr saddr; + socklen_t addrlen; + ASSERT_THAT(accept(socket_, &saddr, &addrlen), + SyscallFailsWithErrno(ENOTSUP)); +} + +// Test that the socket is writable immediately. +TEST_F(RawHDRINCL, PollWritableImmediately) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + struct pollfd pfd = {}; + pfd.fd = socket_; + pfd.events = POLLOUT; + ASSERT_THAT(RetryEINTR(poll)(&pfd, 1, 0), SyscallSucceedsWithValue(1)); +} + +// Test that the socket isn't readable. +TEST_F(RawHDRINCL, NotReadable) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + // Try to receive data with MSG_DONTWAIT, which returns immediately if there's + // nothing to be read. + char buf[117]; + ASSERT_THAT(RetryEINTR(recv)(socket_, buf, sizeof(buf), MSG_DONTWAIT), + SyscallFailsWithErrno(EINVAL)); +} + +// Test that we can connect() to a valid IP (loopback). +TEST_F(RawHDRINCL, ConnectToLoopback) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + ASSERT_THAT(connect(socket_, reinterpret_cast(&addr_), + sizeof(addr_)), + SyscallSucceeds()); +} + +TEST_F(RawHDRINCL, SendWithoutConnectSucceeds) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + struct iphdr hdr = LoopbackHeader(); + ASSERT_THAT(send(socket_, &hdr, sizeof(hdr), 0), + SyscallSucceedsWithValue(sizeof(hdr))); +} + +// HDRINCL implies write-only. Verify that we can't read a packet sent to +// loopback. +TEST_F(RawHDRINCL, NotReadableAfterWrite) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + ASSERT_THAT(connect(socket_, reinterpret_cast(&addr_), + sizeof(addr_)), + SyscallSucceeds()); + + // Construct a packet with an IP header, UDP header, and payload. + constexpr char kPayload[] = "odst"; + char packet[sizeof(struct iphdr) + sizeof(struct udphdr) + sizeof(kPayload)]; + ASSERT_TRUE(FillPacket(packet, sizeof(packet), 40000 /* port */, kPayload, + sizeof(kPayload))); + + socklen_t addrlen = sizeof(addr_); + ASSERT_NO_FATAL_FAILURE( + sendto(socket_, reinterpret_cast(&packet), sizeof(packet), 0, + reinterpret_cast(&addr_), addrlen)); + + struct pollfd pfd = {}; + pfd.fd = socket_; + pfd.events = POLLIN; + ASSERT_THAT(RetryEINTR(poll)(&pfd, 1, 1000), SyscallSucceedsWithValue(0)); +} + +TEST_F(RawHDRINCL, WriteTooSmall) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + ASSERT_THAT(connect(socket_, reinterpret_cast(&addr_), + sizeof(addr_)), + SyscallSucceeds()); + + // This is smaller than the size of an IP header. + constexpr char kBuf[] = "JP5"; + ASSERT_THAT(send(socket_, kBuf, sizeof(kBuf), 0), + SyscallFailsWithErrno(EINVAL)); +} + +// Bind to localhost. +TEST_F(RawHDRINCL, BindToLocalhost) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + ASSERT_THAT( + bind(socket_, reinterpret_cast(&addr_), sizeof(addr_)), + SyscallSucceeds()); +} + +// Bind to a different address. +TEST_F(RawHDRINCL, BindToInvalid) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + struct sockaddr_in bind_addr = {}; + bind_addr.sin_family = AF_INET; + bind_addr.sin_addr = {1}; // 1.0.0.0 - An address that we can't bind to. + ASSERT_THAT(bind(socket_, reinterpret_cast(&bind_addr), + sizeof(bind_addr)), + SyscallFailsWithErrno(EADDRNOTAVAIL)); +} + +// Send and receive a packet. +TEST_F(RawHDRINCL, SendAndReceive) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + int port = 40000; + if (!IsRunningOnGvisor()) { + port = static_cast(ASSERT_NO_ERRNO_AND_VALUE( + PortAvailable(0, AddressFamily::kIpv4, SocketType::kUdp, false))); + } + + // IPPROTO_RAW sockets are write-only. We'll have to open another socket to + // read what we write. + FileDescriptor udp_sock = + ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_RAW, IPPROTO_UDP)); + + // Construct a packet with an IP header, UDP header, and payload. + constexpr char kPayload[] = "toto"; + char packet[sizeof(struct iphdr) + sizeof(struct udphdr) + sizeof(kPayload)]; + ASSERT_TRUE( + FillPacket(packet, sizeof(packet), port, kPayload, sizeof(kPayload))); + + socklen_t addrlen = sizeof(addr_); + ASSERT_NO_FATAL_FAILURE(sendto(socket_, &packet, sizeof(packet), 0, + reinterpret_cast(&addr_), + addrlen)); + + // Receive the payload. + char recv_buf[sizeof(packet)]; + struct sockaddr_in src; + socklen_t src_size = sizeof(src); + ASSERT_THAT(recvfrom(udp_sock.get(), recv_buf, sizeof(recv_buf), 0, + reinterpret_cast(&src), &src_size), + SyscallSucceedsWithValue(sizeof(packet))); + EXPECT_EQ( + memcmp(kPayload, recv_buf + sizeof(struct iphdr) + sizeof(struct udphdr), + sizeof(kPayload)), + 0); + // The network stack should have set the source address. + EXPECT_EQ(src.sin_family, AF_INET); + EXPECT_EQ(absl::gbswap_32(src.sin_addr.s_addr), INADDR_LOOPBACK); + // The packet ID should be 0, as the packet is less than 68 bytes. + struct iphdr iphdr = {}; + memcpy(&iphdr, recv_buf, sizeof(iphdr)); + EXPECT_EQ(iphdr.id, 0); +} + +// Send and receive a packet with nonzero IP ID. +TEST_F(RawHDRINCL, SendAndReceiveNonzeroID) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + int port = 40000; + if (!IsRunningOnGvisor()) { + port = static_cast(ASSERT_NO_ERRNO_AND_VALUE( + PortAvailable(0, AddressFamily::kIpv4, SocketType::kUdp, false))); + } + + // IPPROTO_RAW sockets are write-only. We'll have to open another socket to + // read what we write. + FileDescriptor udp_sock = + ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_RAW, IPPROTO_UDP)); + + // Construct a packet with an IP header, UDP header, and payload. Make the + // payload large enough to force an IP ID to be assigned. + constexpr char kPayload[128] = {}; + char packet[sizeof(struct iphdr) + sizeof(struct udphdr) + sizeof(kPayload)]; + ASSERT_TRUE( + FillPacket(packet, sizeof(packet), port, kPayload, sizeof(kPayload))); + + socklen_t addrlen = sizeof(addr_); + ASSERT_NO_FATAL_FAILURE(sendto(socket_, &packet, sizeof(packet), 0, + reinterpret_cast(&addr_), + addrlen)); + + // Receive the payload. + char recv_buf[sizeof(packet)]; + struct sockaddr_in src; + socklen_t src_size = sizeof(src); + ASSERT_THAT(recvfrom(udp_sock.get(), recv_buf, sizeof(recv_buf), 0, + reinterpret_cast(&src), &src_size), + SyscallSucceedsWithValue(sizeof(packet))); + EXPECT_EQ( + memcmp(kPayload, recv_buf + sizeof(struct iphdr) + sizeof(struct udphdr), + sizeof(kPayload)), + 0); + // The network stack should have set the source address. + EXPECT_EQ(src.sin_family, AF_INET); + EXPECT_EQ(absl::gbswap_32(src.sin_addr.s_addr), INADDR_LOOPBACK); + // The packet ID should not be 0, as the packet was more than 68 bytes. + struct iphdr* iphdr = reinterpret_cast(recv_buf); + EXPECT_NE(iphdr->id, 0); +} + +// Send and receive a packet where the sendto address is not the same as the +// provided destination. +TEST_F(RawHDRINCL, SendAndReceiveDifferentAddress) { + SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); + + int port = 40000; + if (!IsRunningOnGvisor()) { + port = static_cast(ASSERT_NO_ERRNO_AND_VALUE( + PortAvailable(0, AddressFamily::kIpv4, SocketType::kUdp, false))); + } + + // IPPROTO_RAW sockets are write-only. We'll have to open another socket to + // read what we write. + FileDescriptor udp_sock = + ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_RAW, IPPROTO_UDP)); + + // Construct a packet with an IP header, UDP header, and payload. + constexpr char kPayload[] = "toto"; + char packet[sizeof(struct iphdr) + sizeof(struct udphdr) + sizeof(kPayload)]; + ASSERT_TRUE( + FillPacket(packet, sizeof(packet), port, kPayload, sizeof(kPayload))); + // Overwrite the IP destination address with an IP we can't get to. + struct iphdr iphdr = {}; + memcpy(&iphdr, packet, sizeof(iphdr)); + iphdr.daddr = 42; + memcpy(packet, &iphdr, sizeof(iphdr)); + + socklen_t addrlen = sizeof(addr_); + ASSERT_NO_FATAL_FAILURE(sendto(socket_, &packet, sizeof(packet), 0, + reinterpret_cast(&addr_), + addrlen)); + + // Receive the payload, since sendto should replace the bad destination with + // localhost. + char recv_buf[sizeof(packet)]; + struct sockaddr_in src; + socklen_t src_size = sizeof(src); + ASSERT_THAT(recvfrom(udp_sock.get(), recv_buf, sizeof(recv_buf), 0, + reinterpret_cast(&src), &src_size), + SyscallSucceedsWithValue(sizeof(packet))); + EXPECT_EQ( + memcmp(kPayload, recv_buf + sizeof(struct iphdr) + sizeof(struct udphdr), + sizeof(kPayload)), + 0); + // The network stack should have set the source address. + EXPECT_EQ(src.sin_family, AF_INET); + EXPECT_EQ(absl::gbswap_32(src.sin_addr.s_addr), INADDR_LOOPBACK); + // The packet ID should be 0, as the packet is less than 68 bytes. + struct iphdr recv_iphdr = {}; + memcpy(&recv_iphdr, recv_buf, sizeof(recv_iphdr)); + EXPECT_EQ(recv_iphdr.id, 0); + // The destination address should be localhost, not the bad IP we set + // initially. + EXPECT_EQ(absl::gbswap_32(recv_iphdr.daddr), INADDR_LOOPBACK); +} + +} // namespace + +} // namespace testing +} // namespace gvisor -- cgit v1.2.3