// 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 "gtest/gtest.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 { // Compute the internet checksum of the ICMP header (assuming no payload). static uint16_t Checksum(struct icmphdr* icmp) { uint32_t total = 0; uint16_t* num = reinterpret_cast(icmp); // This is just the ICMP header, so there's an even number of bytes. static_assert( sizeof(*icmp) % sizeof(*num) == 0, "sizeof(struct icmphdr) is not an integer multiple of sizeof(uint16_t)"); for (unsigned int i = 0; i < sizeof(*icmp); i += sizeof(*num)) { total += *num; num++; } // Combine the upper and lower 16 bits. This happens twice in case the first // combination causes a carry. unsigned short upper = total >> 16; unsigned short lower = total & 0xffff; total = upper + lower; upper = total >> 16; lower = total & 0xffff; total = upper + lower; return ~total; } // The size of an empty ICMP packet and IP header together. constexpr size_t kEmptyICMPSize = 28; // ICMP raw sockets get their own special tests because Linux automatically // responds to ICMP echo requests, and thus a single echo request sent via // loopback leads to 2 received ICMP packets. class RawSocketICMPTest : public ::testing::Test { protected: // Creates a socket to be used in tests. void SetUp() override; // Closes the socket created by SetUp(). void TearDown() override; // Checks that both an ICMP echo request and reply are received. Calls should // be wrapped in ASSERT_NO_FATAL_FAILURE. void ExpectICMPSuccess(const struct icmphdr& icmp); // Sends icmp via s_. void SendEmptyICMP(const struct icmphdr& icmp); // Sends icmp via s_ to the given address. void SendEmptyICMPTo(int sock, const struct sockaddr_in& addr, const struct icmphdr& icmp); // Reads from s_ into recv_buf. void ReceiveICMP(char* recv_buf, size_t recv_buf_len, size_t expected_size, struct sockaddr_in* src); // Reads from sock into recv_buf. void ReceiveICMPFrom(char* recv_buf, size_t recv_buf_len, size_t expected_size, struct sockaddr_in* src, int sock); // The socket used for both reading and writing. int s_; // The loopback address. struct sockaddr_in addr_; }; void RawSocketICMPTest::SetUp() { SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); ASSERT_THAT(s_ = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP), SyscallSucceeds()); addr_ = {}; // "On raw sockets sin_port is set to the IP protocol." - ip(7). addr_.sin_port = IPPROTO_IP; addr_.sin_addr.s_addr = htonl(INADDR_LOOPBACK); addr_.sin_family = AF_INET; } void RawSocketICMPTest::TearDown() { SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); EXPECT_THAT(close(s_), SyscallSucceeds()); } // We'll only read an echo in this case, as the kernel won't respond to the // malformed ICMP checksum. TEST_F(RawSocketICMPTest, SendAndReceiveBadChecksum) { SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); // Prepare and send an ICMP packet. Use arbitrary junk for checksum, sequence, // and ID. None of that should matter for raw sockets - the kernel should // still give us the packet. struct icmphdr icmp; icmp.type = ICMP_ECHO; icmp.code = 0; icmp.checksum = 0; icmp.un.echo.sequence = 2012; icmp.un.echo.id = 2014; ASSERT_NO_FATAL_FAILURE(SendEmptyICMP(icmp)); // Veryify that we get the echo, then that there's nothing else to read. char recv_buf[kEmptyICMPSize]; struct sockaddr_in src; ASSERT_NO_FATAL_FAILURE( ReceiveICMP(recv_buf, sizeof(recv_buf), sizeof(struct icmphdr), &src)); EXPECT_EQ(memcmp(&src, &addr_, sizeof(src)), 0); // The packet should be identical to what we sent. EXPECT_EQ(memcmp(recv_buf + sizeof(struct iphdr), &icmp, sizeof(icmp)), 0); // And there should be nothing left to read. EXPECT_THAT(RetryEINTR(recv)(s_, recv_buf, sizeof(recv_buf), MSG_DONTWAIT), SyscallFailsWithErrno(EAGAIN)); } // // Send and receive an ICMP packet. TEST_F(RawSocketICMPTest, SendAndReceive) { SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); // Prepare and send an ICMP packet. Use arbitrary junk for sequence and ID. // None of that should matter for raw sockets - the kernel should still give // us the packet. struct icmphdr icmp; icmp.type = ICMP_ECHO; icmp.code = 0; icmp.checksum = 0; icmp.un.echo.sequence = 2012; icmp.un.echo.id = 2014; icmp.checksum = Checksum(&icmp); ASSERT_NO_FATAL_FAILURE(SendEmptyICMP(icmp)); ASSERT_NO_FATAL_FAILURE(ExpectICMPSuccess(icmp)); } // We should be able to create multiple raw sockets for the same protocol and // receive the same packet on both. TEST_F(RawSocketICMPTest, MultipleSocketReceive) { SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); FileDescriptor s2 = ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)); // Prepare and send an ICMP packet. Use arbitrary junk for sequence and ID. // None of that should matter for raw sockets - the kernel should still give // us the packet. struct icmphdr icmp; icmp.type = ICMP_ECHO; icmp.code = 0; icmp.checksum = 0; icmp.un.echo.sequence = 2016; icmp.un.echo.id = 2018; icmp.checksum = Checksum(&icmp); ASSERT_NO_FATAL_FAILURE(SendEmptyICMP(icmp)); // Both sockets will receive the echo request and reply in indeterminate // order, so we'll need to read 2 packets from each. // Receive on socket 1. constexpr int kBufSize = kEmptyICMPSize; char recv_buf1[2][kBufSize]; struct sockaddr_in src; for (int i = 0; i < 2; i++) { ASSERT_NO_FATAL_FAILURE(ReceiveICMP(recv_buf1[i], ABSL_ARRAYSIZE(recv_buf1[i]), sizeof(struct icmphdr), &src)); EXPECT_EQ(memcmp(&src, &addr_, sizeof(src)), 0); } // Receive on socket 2. char recv_buf2[2][kBufSize]; for (int i = 0; i < 2; i++) { ASSERT_NO_FATAL_FAILURE( ReceiveICMPFrom(recv_buf2[i], ABSL_ARRAYSIZE(recv_buf2[i]), sizeof(struct icmphdr), &src, s2.get())); EXPECT_EQ(memcmp(&src, &addr_, sizeof(src)), 0); } // Ensure both sockets receive identical packets. int types[] = {ICMP_ECHO, ICMP_ECHOREPLY}; for (int type : types) { auto match_type = [=](char buf[kBufSize]) { struct icmphdr* icmp = reinterpret_cast(buf + sizeof(struct iphdr)); return icmp->type == type; }; auto icmp1_it = std::find_if(std::begin(recv_buf1), std::end(recv_buf1), match_type); auto icmp2_it = std::find_if(std::begin(recv_buf2), std::end(recv_buf2), match_type); ASSERT_NE(icmp1_it, std::end(recv_buf1)); ASSERT_NE(icmp2_it, std::end(recv_buf2)); EXPECT_EQ(memcmp(*icmp1_it + sizeof(struct iphdr), *icmp2_it + sizeof(struct iphdr), sizeof(icmp)), 0); } } // A raw ICMP socket and ping socket should both receive the ICMP packets // intended for the ping socket. TEST_F(RawSocketICMPTest, RawAndPingSockets) { SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); FileDescriptor ping_sock = ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP)); // Ping sockets take care of the ICMP ID and checksum. struct icmphdr icmp; icmp.type = ICMP_ECHO; icmp.code = 0; icmp.un.echo.sequence = *static_cast(&icmp.un.echo.sequence); ASSERT_THAT(RetryEINTR(sendto)(ping_sock.get(), &icmp, sizeof(icmp), 0, reinterpret_cast(&addr_), sizeof(addr_)), SyscallSucceedsWithValue(sizeof(icmp))); // Receive on socket 1, which receives the echo request and reply in // indeterminate order. constexpr int kBufSize = kEmptyICMPSize; char recv_buf1[2][kBufSize]; struct sockaddr_in src; for (int i = 0; i < 2; i++) { ASSERT_NO_FATAL_FAILURE( ReceiveICMP(recv_buf1[i], kBufSize, sizeof(struct icmphdr), &src)); EXPECT_EQ(memcmp(&src, &addr_, sizeof(src)), 0); } // Receive on socket 2. Ping sockets only get the echo reply, not the initial // echo. char ping_recv_buf[kBufSize]; ASSERT_THAT(RetryEINTR(recv)(ping_sock.get(), ping_recv_buf, kBufSize, 0), SyscallSucceedsWithValue(sizeof(struct icmphdr))); // Ensure both sockets receive identical echo reply packets. auto match_type_raw = [=](char buf[kBufSize]) { struct icmphdr* icmp = reinterpret_cast(buf + sizeof(struct iphdr)); return icmp->type == ICMP_ECHOREPLY; }; auto raw_reply_it = std::find_if(std::begin(recv_buf1), std::end(recv_buf1), match_type_raw); ASSERT_NE(raw_reply_it, std::end(recv_buf1)); EXPECT_EQ( memcmp(*raw_reply_it + sizeof(struct iphdr), ping_recv_buf, sizeof(icmp)), 0); } // A raw ICMP socket should be able to send a malformed short ICMP Echo Request, // while ping socket should not. // Neither should be able to receieve a short malformed packet. TEST_F(RawSocketICMPTest, ShortEchoRawAndPingSockets) { SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); FileDescriptor ping_sock = ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP)); struct icmphdr icmp; icmp.type = ICMP_ECHO; icmp.code = 0; icmp.un.echo.sequence = 0; icmp.un.echo.id = 6789; icmp.checksum = 0; icmp.checksum = Checksum(&icmp); // Omit 2 bytes from ICMP packet. constexpr int kShortICMPSize = sizeof(icmp) - 2; // Sending a malformed short ICMP message to a ping socket should fail. ASSERT_THAT(RetryEINTR(sendto)(ping_sock.get(), &icmp, kShortICMPSize, 0, reinterpret_cast(&addr_), sizeof(addr_)), SyscallFailsWithErrno(EINVAL)); // Sending a malformed short ICMP message to a raw socket should not fail. ASSERT_THAT(RetryEINTR(sendto)(s_, &icmp, kShortICMPSize, 0, reinterpret_cast(&addr_), sizeof(addr_)), SyscallSucceedsWithValue(kShortICMPSize)); // Neither Ping nor Raw socket should have anything to read. char recv_buf[kEmptyICMPSize]; EXPECT_THAT(RetryEINTR(recv)(ping_sock.get(), recv_buf, sizeof(recv_buf), MSG_DONTWAIT), SyscallFailsWithErrno(EAGAIN)); EXPECT_THAT(RetryEINTR(recv)(s_, recv_buf, sizeof(recv_buf), MSG_DONTWAIT), SyscallFailsWithErrno(EAGAIN)); } // A raw ICMP socket should be able to send a malformed short ICMP Echo Reply, // while ping socket should not. // Neither should be able to receieve a short malformed packet. TEST_F(RawSocketICMPTest, ShortEchoReplyRawAndPingSockets) { SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); FileDescriptor ping_sock = ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP)); struct icmphdr icmp; icmp.type = ICMP_ECHOREPLY; icmp.code = 0; icmp.un.echo.sequence = 0; icmp.un.echo.id = 6789; icmp.checksum = 0; icmp.checksum = Checksum(&icmp); // Omit 2 bytes from ICMP packet. constexpr int kShortICMPSize = sizeof(icmp) - 2; // Sending a malformed short ICMP message to a ping socket should fail. ASSERT_THAT(RetryEINTR(sendto)(ping_sock.get(), &icmp, kShortICMPSize, 0, reinterpret_cast(&addr_), sizeof(addr_)), SyscallFailsWithErrno(EINVAL)); // Sending a malformed short ICMP message to a raw socket should not fail. ASSERT_THAT(RetryEINTR(sendto)(s_, &icmp, kShortICMPSize, 0, reinterpret_cast(&addr_), sizeof(addr_)), SyscallSucceedsWithValue(kShortICMPSize)); // Neither Ping nor Raw socket should have anything to read. char recv_buf[kEmptyICMPSize]; EXPECT_THAT(RetryEINTR(recv)(ping_sock.get(), recv_buf, sizeof(recv_buf), MSG_DONTWAIT), SyscallFailsWithErrno(EAGAIN)); EXPECT_THAT(RetryEINTR(recv)(s_, recv_buf, sizeof(recv_buf), MSG_DONTWAIT), SyscallFailsWithErrno(EAGAIN)); } // Test that connect() sends packets to the right place. TEST_F(RawSocketICMPTest, SendAndReceiveViaConnect) { SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); ASSERT_THAT( connect(s_, reinterpret_cast(&addr_), sizeof(addr_)), SyscallSucceeds()); // Prepare and send an ICMP packet. Use arbitrary junk for sequence and ID. // None of that should matter for raw sockets - the kernel should still give // us the packet. struct icmphdr icmp; icmp.type = ICMP_ECHO; icmp.code = 0; icmp.checksum = 0; icmp.un.echo.sequence = 2003; icmp.un.echo.id = 2004; icmp.checksum = Checksum(&icmp); ASSERT_THAT(send(s_, &icmp, sizeof(icmp), 0), SyscallSucceedsWithValue(sizeof(icmp))); ASSERT_NO_FATAL_FAILURE(ExpectICMPSuccess(icmp)); } // Bind to localhost, then send and receive packets. TEST_F(RawSocketICMPTest, BindSendAndReceive) { SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); ASSERT_THAT( bind(s_, reinterpret_cast(&addr_), sizeof(addr_)), SyscallSucceeds()); // Prepare and send an ICMP packet. Use arbitrary junk for checksum, sequence, // and ID. None of that should matter for raw sockets - the kernel should // still give us the packet. struct icmphdr icmp; icmp.type = ICMP_ECHO; icmp.code = 0; icmp.checksum = 0; icmp.un.echo.sequence = 2004; icmp.un.echo.id = 2007; icmp.checksum = Checksum(&icmp); ASSERT_NO_FATAL_FAILURE(SendEmptyICMP(icmp)); ASSERT_NO_FATAL_FAILURE(ExpectICMPSuccess(icmp)); } // Bind and connect to localhost and send/receive packets. TEST_F(RawSocketICMPTest, BindConnectSendAndReceive) { SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW))); ASSERT_THAT( bind(s_, reinterpret_cast(&addr_), sizeof(addr_)), SyscallSucceeds()); ASSERT_THAT( connect(s_, reinterpret_cast(&addr_), sizeof(addr_)), SyscallSucceeds()); // Prepare and send an ICMP packet. Use arbitrary junk for checksum, sequence, // and ID. None of that should matter for raw sockets - the kernel should // still give us the packet. struct icmphdr icmp; icmp.type = ICMP_ECHO; icmp.code = 0; icmp.checksum = 0; icmp.un.echo.sequence = 2010; icmp.un.echo.id = 7; icmp.checksum = Checksum(&icmp); ASSERT_NO_FATAL_FAILURE(SendEmptyICMP(icmp)); ASSERT_NO_FATAL_FAILURE(ExpectICMPSuccess(icmp)); } void RawSocketICMPTest::ExpectICMPSuccess(const struct icmphdr& icmp) { // We're going to receive both the echo request and reply, but the order is // indeterminate. char recv_buf[kEmptyICMPSize]; struct sockaddr_in src; bool received_request = false; bool received_reply = false; for (int i = 0; i < 2; i++) { // Receive the packet. ASSERT_NO_FATAL_FAILURE(ReceiveICMP(recv_buf, ABSL_ARRAYSIZE(recv_buf), sizeof(struct icmphdr), &src)); EXPECT_EQ(memcmp(&src, &addr_, sizeof(src)), 0); struct icmphdr* recvd_icmp = reinterpret_cast(recv_buf + sizeof(struct iphdr)); switch (recvd_icmp->type) { case ICMP_ECHO: EXPECT_FALSE(received_request); received_request = true; // The packet should be identical to what we sent. EXPECT_EQ(memcmp(recv_buf + sizeof(struct iphdr), &icmp, sizeof(icmp)), 0); break; case ICMP_ECHOREPLY: EXPECT_FALSE(received_reply); received_reply = true; // Most fields should be the same. EXPECT_EQ(recvd_icmp->code, icmp.code); EXPECT_EQ(recvd_icmp->un.echo.sequence, icmp.un.echo.sequence); EXPECT_EQ(recvd_icmp->un.echo.id, icmp.un.echo.id); // A couple are different. EXPECT_EQ(recvd_icmp->type, ICMP_ECHOREPLY); // The checksum computed over the reply should still be valid. EXPECT_EQ(Checksum(recvd_icmp), 0); break; } } ASSERT_TRUE(received_request); ASSERT_TRUE(received_reply); } void RawSocketICMPTest::SendEmptyICMP(const struct icmphdr& icmp) { ASSERT_NO_FATAL_FAILURE(SendEmptyICMPTo(s_, addr_, icmp)); } void RawSocketICMPTest::SendEmptyICMPTo(int sock, const struct sockaddr_in& addr, const struct icmphdr& icmp) { // It's safe to use const_cast here because sendmsg won't modify the iovec or // address. struct iovec iov = {}; iov.iov_base = static_cast(const_cast(&icmp)); iov.iov_len = sizeof(icmp); struct msghdr msg = {}; msg.msg_name = static_cast(const_cast(&addr)); msg.msg_namelen = sizeof(addr); msg.msg_iov = &iov; msg.msg_iovlen = 1; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_flags = 0; ASSERT_THAT(sendmsg(sock, &msg, 0), SyscallSucceedsWithValue(sizeof(icmp))); } void RawSocketICMPTest::ReceiveICMP(char* recv_buf, size_t recv_buf_len, size_t expected_size, struct sockaddr_in* src) { ASSERT_NO_FATAL_FAILURE( ReceiveICMPFrom(recv_buf, recv_buf_len, expected_size, src, s_)); } void RawSocketICMPTest::ReceiveICMPFrom(char* recv_buf, size_t recv_buf_len, size_t expected_size, struct sockaddr_in* src, int sock) { struct iovec iov = {}; iov.iov_base = recv_buf; iov.iov_len = recv_buf_len; struct msghdr msg = {}; msg.msg_name = src; msg.msg_namelen = sizeof(*src); msg.msg_iov = &iov; msg.msg_iovlen = 1; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_flags = 0; // We should receive the ICMP packet plus 20 bytes of IP header. ASSERT_THAT(recvmsg(sock, &msg, 0), SyscallSucceedsWithValue(expected_size + sizeof(struct iphdr))); } } // namespace } // namespace testing } // namespace gvisor