// 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 <arpa/inet.h> #include <ifaddrs.h> #include <linux/capability.h> #include <linux/if_arp.h> #include <linux/if_packet.h> #include <net/ethernet.h> #include <netinet/in.h> #include <netinet/ip.h> #include <netinet/udp.h> #include <poll.h> #include <sys/ioctl.h> #include <sys/socket.h> #include <sys/types.h> #include <unistd.h> #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" // Some of these tests involve sending packets via AF_PACKET sockets and the // loopback interface. Because AF_PACKET circumvents so much of the networking // stack, Linux sees these packets as "martian", i.e. they claim to be to/from // localhost but don't have the usual associated data. Thus Linux drops them by // default. You can see where this happens by following the code at: // // - net/ipv4/ip_input.c:ip_rcv_finish, which calls // - net/ipv4/route.c:ip_route_input_noref, which calls // - net/ipv4/route.c:ip_route_input_slow, which finds and drops martian // packets. // // To tell Linux not to drop these packets, you need to tell it to accept our // funny packets (which are completely valid and correct, but lack associated // in-kernel data because we use AF_PACKET): // // echo 1 >> /proc/sys/net/ipv4/conf/lo/accept_local // echo 1 >> /proc/sys/net/ipv4/conf/lo/route_localnet // // These tests require CAP_NET_RAW to run. // TODO(gvisor.dev/issue/173): gVisor support. namespace gvisor { namespace testing { namespace { using ::testing::AnyOf; using ::testing::Eq; constexpr char kMessage[] = "soweoneul malhaebwa"; constexpr in_port_t kPort = 0x409c; // htons(40000) // // "Cooked" tests. Cooked AF_PACKET sockets do not contain link layer // headers, and provide link layer destination/source information via a // returned struct sockaddr_ll. // // Send kMessage via sock to loopback void SendUDPMessage(int sock) { struct sockaddr_in dest = {}; dest.sin_port = kPort; dest.sin_addr.s_addr = htonl(INADDR_LOOPBACK); dest.sin_family = AF_INET; EXPECT_THAT(sendto(sock, kMessage, sizeof(kMessage), 0, reinterpret_cast<struct sockaddr*>(&dest), sizeof(dest)), SyscallSucceedsWithValue(sizeof(kMessage))); } // Send an IP packet and make sure ETH_P_<something else> doesn't pick it up. TEST(BasicCookedPacketTest, WrongType) { if (!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))) { ASSERT_THAT(socket(AF_PACKET, SOCK_DGRAM, ETH_P_PUP), SyscallFailsWithErrno(EPERM)); GTEST_SKIP(); } FileDescriptor sock = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_PACKET, SOCK_DGRAM, htons(ETH_P_PUP))); // Let's use a simple IP payload: a UDP datagram. FileDescriptor udp_sock = ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_DGRAM, 0)); SendUDPMessage(udp_sock.get()); // Wait and make sure the socket never becomes readable. struct pollfd pfd = {}; pfd.fd = sock.get(); pfd.events = POLLIN; EXPECT_THAT(RetryEINTR(poll)(&pfd, 1, 1000), SyscallSucceedsWithValue(0)); } // Tests for "cooked" (SOCK_DGRAM) packet(7) sockets. class CookedPacketTest : public ::testing::TestWithParam<int> { protected: // Creates a socket to be used in tests. void SetUp() override; // Closes the socket created by SetUp(). void TearDown() override; // Gets the device index of the loopback device. int GetLoopbackIndex(); // The socket used for both reading and writing. int socket_; }; void CookedPacketTest::SetUp() { if (!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))) { ASSERT_THAT(socket(AF_PACKET, SOCK_DGRAM, htons(GetParam())), SyscallFailsWithErrno(EPERM)); GTEST_SKIP(); } if (!IsRunningOnGvisor()) { FileDescriptor acceptLocal = ASSERT_NO_ERRNO_AND_VALUE( Open("/proc/sys/net/ipv4/conf/lo/accept_local", O_RDONLY)); FileDescriptor routeLocalnet = ASSERT_NO_ERRNO_AND_VALUE( Open("/proc/sys/net/ipv4/conf/lo/route_localnet", O_RDONLY)); char enabled; ASSERT_THAT(read(acceptLocal.get(), &enabled, 1), SyscallSucceedsWithValue(1)); ASSERT_EQ(enabled, '1'); ASSERT_THAT(read(routeLocalnet.get(), &enabled, 1), SyscallSucceedsWithValue(1)); ASSERT_EQ(enabled, '1'); } ASSERT_THAT(socket_ = socket(AF_PACKET, SOCK_DGRAM, htons(GetParam())), SyscallSucceeds()); } void CookedPacketTest::TearDown() { // TearDown will be run even if we skip the test. if (ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))) { EXPECT_THAT(close(socket_), SyscallSucceeds()); } } int CookedPacketTest::GetLoopbackIndex() { struct ifreq ifr; snprintf(ifr.ifr_name, IFNAMSIZ, "lo"); EXPECT_THAT(ioctl(socket_, SIOCGIFINDEX, &ifr), SyscallSucceeds()); EXPECT_NE(ifr.ifr_ifindex, 0); return ifr.ifr_ifindex; } // Receive and verify the message via packet socket on interface. void ReceiveMessage(int sock, int ifindex) { // Wait for the socket to become readable. struct pollfd pfd = {}; pfd.fd = sock; pfd.events = POLLIN; EXPECT_THAT(RetryEINTR(poll)(&pfd, 1, 2000), SyscallSucceedsWithValue(1)); // Read and verify the data. constexpr size_t packet_size = sizeof(struct iphdr) + sizeof(struct udphdr) + sizeof(kMessage); char buf[64]; struct sockaddr_ll src = {}; socklen_t src_len = sizeof(src); ASSERT_THAT(recvfrom(sock, buf, sizeof(buf), 0, reinterpret_cast<struct sockaddr*>(&src), &src_len), SyscallSucceedsWithValue(packet_size)); // sockaddr_ll ends with an 8 byte physical address field, but ethernet // addresses only use 6 bytes. Linux used to return sizeof(sockaddr_ll)-2 // here, but since commit b2cf86e1563e33a14a1c69b3e508d15dc12f804c returns // sizeof(sockaddr_ll). ASSERT_THAT(src_len, AnyOf(Eq(sizeof(src)), Eq(sizeof(src) - 2))); // TODO(b/129292371): Verify protocol once we return it. // Verify the source address. EXPECT_EQ(src.sll_family, AF_PACKET); EXPECT_EQ(src.sll_ifindex, ifindex); EXPECT_EQ(src.sll_halen, ETH_ALEN); EXPECT_EQ(ntohs(src.sll_protocol), ETH_P_IP); // This came from the loopback device, so the address is all 0s. for (int i = 0; i < src.sll_halen; i++) { EXPECT_EQ(src.sll_addr[i], 0); } // Verify the IP header. We memcpy to deal with pointer aligment. struct iphdr ip = {}; memcpy(&ip, buf, sizeof(ip)); EXPECT_EQ(ip.ihl, 5); EXPECT_EQ(ip.version, 4); EXPECT_EQ(ip.tot_len, htons(packet_size)); EXPECT_EQ(ip.protocol, IPPROTO_UDP); EXPECT_EQ(ip.daddr, htonl(INADDR_LOOPBACK)); EXPECT_EQ(ip.saddr, htonl(INADDR_LOOPBACK)); // Verify the UDP header. We memcpy to deal with pointer aligment. struct udphdr udp = {}; memcpy(&udp, buf + sizeof(iphdr), sizeof(udp)); EXPECT_EQ(udp.dest, kPort); EXPECT_EQ(udp.len, htons(sizeof(udphdr) + sizeof(kMessage))); // Verify the payload. char* payload = reinterpret_cast<char*>(buf + sizeof(iphdr) + sizeof(udphdr)); EXPECT_EQ(strncmp(payload, kMessage, sizeof(kMessage)), 0); } // Receive via a packet socket. TEST_P(CookedPacketTest, Receive) { // Let's use a simple IP payload: a UDP datagram. FileDescriptor udp_sock = ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_DGRAM, 0)); SendUDPMessage(udp_sock.get()); // Receive and verify the data. int loopback_index = GetLoopbackIndex(); ReceiveMessage(socket_, loopback_index); } // Send via a packet socket. TEST_P(CookedPacketTest, Send) { // TODO(b/129292371): Remove once we support packet socket writing. SKIP_IF(IsRunningOnGvisor()); // Let's send a UDP packet and receive it using a regular UDP socket. FileDescriptor udp_sock = ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_DGRAM, 0)); struct sockaddr_in bind_addr = {}; bind_addr.sin_family = AF_INET; bind_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK); bind_addr.sin_port = kPort; ASSERT_THAT( bind(udp_sock.get(), reinterpret_cast<struct sockaddr*>(&bind_addr), sizeof(bind_addr)), SyscallSucceeds()); // Set up the destination physical address. struct sockaddr_ll dest = {}; dest.sll_family = AF_PACKET; dest.sll_halen = ETH_ALEN; dest.sll_ifindex = GetLoopbackIndex(); dest.sll_protocol = htons(ETH_P_IP); // We're sending to the loopback device, so the address is all 0s. memset(dest.sll_addr, 0x00, ETH_ALEN); // Set up the IP header. struct iphdr iphdr = {0}; iphdr.ihl = 5; iphdr.version = 4; iphdr.tos = 0; iphdr.tot_len = htons(sizeof(struct iphdr) + sizeof(struct udphdr) + sizeof(kMessage)); // Get a pseudo-random ID. If we clash with an in-use ID the test will fail, // but we have no way of getting an ID we know to be good. srand(*reinterpret_cast<unsigned int*>(&iphdr)); iphdr.id = rand(); // Linux sets this bit ("do not fragment") for small packets. iphdr.frag_off = 1 << 6; iphdr.ttl = 64; iphdr.protocol = IPPROTO_UDP; iphdr.daddr = htonl(INADDR_LOOPBACK); iphdr.saddr = htonl(INADDR_LOOPBACK); iphdr.check = IPChecksum(iphdr); // Set up the UDP header. struct udphdr udphdr = {}; udphdr.source = kPort; udphdr.dest = kPort; udphdr.len = htons(sizeof(udphdr) + sizeof(kMessage)); udphdr.check = UDPChecksum(iphdr, udphdr, kMessage, sizeof(kMessage)); // Copy both headers and the payload into our packet buffer. char send_buf[sizeof(iphdr) + sizeof(udphdr) + sizeof(kMessage)]; memcpy(send_buf, &iphdr, sizeof(iphdr)); memcpy(send_buf + sizeof(iphdr), &udphdr, sizeof(udphdr)); memcpy(send_buf + sizeof(iphdr) + sizeof(udphdr), kMessage, sizeof(kMessage)); // Send it. ASSERT_THAT(sendto(socket_, send_buf, sizeof(send_buf), 0, reinterpret_cast<struct sockaddr*>(&dest), sizeof(dest)), SyscallSucceedsWithValue(sizeof(send_buf))); // Wait for the packet to become available on both sockets. struct pollfd pfd = {}; pfd.fd = udp_sock.get(); pfd.events = POLLIN; ASSERT_THAT(RetryEINTR(poll)(&pfd, 1, 5000), SyscallSucceedsWithValue(1)); pfd.fd = socket_; pfd.events = POLLIN; ASSERT_THAT(RetryEINTR(poll)(&pfd, 1, 5000), SyscallSucceedsWithValue(1)); // Receive on the packet socket. char recv_buf[sizeof(send_buf)]; ASSERT_THAT(recv(socket_, recv_buf, sizeof(recv_buf), 0), SyscallSucceedsWithValue(sizeof(recv_buf))); ASSERT_EQ(memcmp(recv_buf, send_buf, sizeof(send_buf)), 0); // Receive on the UDP socket. struct sockaddr_in src; socklen_t src_len = sizeof(src); ASSERT_THAT(recvfrom(udp_sock.get(), recv_buf, sizeof(recv_buf), MSG_DONTWAIT, reinterpret_cast<struct sockaddr*>(&src), &src_len), SyscallSucceedsWithValue(sizeof(kMessage))); // Check src and payload. EXPECT_EQ(strncmp(recv_buf, kMessage, sizeof(kMessage)), 0); EXPECT_EQ(src.sin_family, AF_INET); EXPECT_EQ(src.sin_port, kPort); EXPECT_EQ(src.sin_addr.s_addr, htonl(INADDR_LOOPBACK)); } // Bind and receive via packet socket. TEST_P(CookedPacketTest, BindReceive) { struct sockaddr_ll bind_addr = {}; bind_addr.sll_family = AF_PACKET; bind_addr.sll_protocol = htons(GetParam()); bind_addr.sll_ifindex = GetLoopbackIndex(); ASSERT_THAT(bind(socket_, reinterpret_cast<struct sockaddr*>(&bind_addr), sizeof(bind_addr)), SyscallSucceeds()); // Let's use a simple IP payload: a UDP datagram. FileDescriptor udp_sock = ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_DGRAM, 0)); SendUDPMessage(udp_sock.get()); // Receive and verify the data. ReceiveMessage(socket_, bind_addr.sll_ifindex); } // Double Bind socket. TEST_P(CookedPacketTest, DoubleBindSucceeds) { struct sockaddr_ll bind_addr = {}; bind_addr.sll_family = AF_PACKET; bind_addr.sll_protocol = htons(GetParam()); bind_addr.sll_ifindex = GetLoopbackIndex(); ASSERT_THAT(bind(socket_, reinterpret_cast<struct sockaddr*>(&bind_addr), sizeof(bind_addr)), SyscallSucceeds()); // Binding socket again should fail. ASSERT_THAT(bind(socket_, reinterpret_cast<struct sockaddr*>(&bind_addr), sizeof(bind_addr)), // Linux 4.09 returns EINVAL here, but some time before 4.19 it // switched to EADDRINUSE. SyscallSucceeds()); } // Bind and verify we do not receive data on interface which is not bound TEST_P(CookedPacketTest, BindDrop) { // Let's use a simple IP payload: a UDP datagram. FileDescriptor udp_sock = ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_DGRAM, 0)); struct ifaddrs* if_addr_list = nullptr; auto cleanup = Cleanup([&if_addr_list]() { freeifaddrs(if_addr_list); }); ASSERT_THAT(getifaddrs(&if_addr_list), SyscallSucceeds()); // Get interface other than loopback. struct ifreq ifr = {}; for (struct ifaddrs* i = if_addr_list; i; i = i->ifa_next) { if (strcmp(i->ifa_name, "lo") != 0) { strncpy(ifr.ifr_name, i->ifa_name, sizeof(ifr.ifr_name)); break; } } // Skip if no interface is available other than loopback. if (strlen(ifr.ifr_name) == 0) { GTEST_SKIP(); } // Get interface index. EXPECT_THAT(ioctl(socket_, SIOCGIFINDEX, &ifr), SyscallSucceeds()); EXPECT_NE(ifr.ifr_ifindex, 0); // Bind to packet socket requires only family, protocol and ifindex. struct sockaddr_ll bind_addr = {}; bind_addr.sll_family = AF_PACKET; bind_addr.sll_protocol = htons(GetParam()); bind_addr.sll_ifindex = ifr.ifr_ifindex; ASSERT_THAT(bind(socket_, reinterpret_cast<struct sockaddr*>(&bind_addr), sizeof(bind_addr)), SyscallSucceeds()); // Send to loopback interface. struct sockaddr_in dest = {}; dest.sin_addr.s_addr = htonl(INADDR_LOOPBACK); dest.sin_family = AF_INET; dest.sin_port = kPort; EXPECT_THAT(sendto(udp_sock.get(), kMessage, sizeof(kMessage), 0, reinterpret_cast<struct sockaddr*>(&dest), sizeof(dest)), SyscallSucceedsWithValue(sizeof(kMessage))); // Wait and make sure the socket never receives any data. struct pollfd pfd = {}; pfd.fd = socket_; pfd.events = POLLIN; EXPECT_THAT(RetryEINTR(poll)(&pfd, 1, 1000), SyscallSucceedsWithValue(0)); } // Bind with invalid address. TEST_P(CookedPacketTest, BindFail) { // Null address. ASSERT_THAT( bind(socket_, nullptr, sizeof(struct sockaddr)), AnyOf(SyscallFailsWithErrno(EFAULT), SyscallFailsWithErrno(EINVAL))); // Address of size 1. uint8_t addr = 0; ASSERT_THAT( bind(socket_, reinterpret_cast<struct sockaddr*>(&addr), sizeof(addr)), SyscallFailsWithErrno(EINVAL)); } INSTANTIATE_TEST_SUITE_P(AllInetTests, CookedPacketTest, ::testing::Values(ETH_P_IP, ETH_P_ALL)); } // namespace } // namespace testing } // namespace gvisor