From 7f204a7de8b08542aca3c1daa96ed20e1177ba87 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Tue, 10 Mar 2020 17:05:27 +0900 Subject: [PATCH] selftests: net: Add SO_REUSEADDR test to check if 4-tuples are fully utilized. This commit adds a test to check if we can fully utilize 4-tuples for connect() when all ephemeral ports are exhausted. The test program changes the local port range to use only one port and binds two sockets with or without SO_REUSEADDR and SO_REUSEPORT, and with the same EUID or with different EUIDs, then do listen(). We should be able to bind only one socket having both SO_REUSEADDR and SO_REUSEPORT per EUID, which restriction is to prevent unintentional listen(). Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller --- tools/testing/selftests/net/.gitignore | 1 + tools/testing/selftests/net/Makefile | 2 + .../selftests/net/reuseaddr_ports_exhausted.c | 162 ++++++++++++++++++ .../net/reuseaddr_ports_exhausted.sh | 35 ++++ 4 files changed, 200 insertions(+) create mode 100644 tools/testing/selftests/net/reuseaddr_ports_exhausted.c create mode 100755 tools/testing/selftests/net/reuseaddr_ports_exhausted.sh diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore index ecc52d4c034d..91f9aea853b1 100644 --- a/tools/testing/selftests/net/.gitignore +++ b/tools/testing/selftests/net/.gitignore @@ -23,3 +23,4 @@ so_txtime tcp_fastopen_backup_key nettest fin_ack_lat +reuseaddr_ports_exhausted \ No newline at end of file diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile index 287ae916ec0b..48063fd69924 100644 --- a/tools/testing/selftests/net/Makefile +++ b/tools/testing/selftests/net/Makefile @@ -12,6 +12,7 @@ TEST_PROGS += udpgro_bench.sh udpgro.sh test_vxlan_under_vrf.sh reuseport_addr_a TEST_PROGS += test_vxlan_fdb_changelink.sh so_txtime.sh ipv6_flowlabel.sh TEST_PROGS += tcp_fastopen_backup_key.sh fcnal-test.sh l2tp.sh traceroute.sh TEST_PROGS += fin_ack_lat.sh +TEST_PROGS += reuseaddr_ports_exhausted.sh TEST_PROGS_EXTENDED := in_netns.sh TEST_GEN_FILES = socket nettest TEST_GEN_FILES += psock_fanout psock_tpacket msg_zerocopy reuseport_addr_any @@ -22,6 +23,7 @@ TEST_GEN_FILES += tcp_fastopen_backup_key TEST_GEN_FILES += fin_ack_lat TEST_GEN_PROGS = reuseport_bpf reuseport_bpf_cpu reuseport_bpf_numa TEST_GEN_PROGS += reuseport_dualstack reuseaddr_conflict tls +TEST_GEN_FILES += reuseaddr_ports_exhausted KSFT_KHDR_INSTALL := 1 include ../lib.mk diff --git a/tools/testing/selftests/net/reuseaddr_ports_exhausted.c b/tools/testing/selftests/net/reuseaddr_ports_exhausted.c new file mode 100644 index 000000000000..7b01b7c2ec10 --- /dev/null +++ b/tools/testing/selftests/net/reuseaddr_ports_exhausted.c @@ -0,0 +1,162 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Check if we can fully utilize 4-tuples for connect(). + * + * Rules to bind sockets to the same port when all ephemeral ports are + * exhausted. + * + * 1. if there are TCP_LISTEN sockets on the port, fail to bind. + * 2. if there are sockets without SO_REUSEADDR, fail to bind. + * 3. if SO_REUSEADDR is disabled, fail to bind. + * 4. if SO_REUSEADDR is enabled and SO_REUSEPORT is disabled, + * succeed to bind. + * 5. if SO_REUSEADDR and SO_REUSEPORT are enabled and + * there is no socket having the both options and the same EUID, + * succeed to bind. + * 6. fail to bind. + * + * Author: Kuniyuki Iwashima + */ +#include +#include +#include +#include +#include +#include "../kselftest_harness.h" + +struct reuse_opts { + int reuseaddr[2]; + int reuseport[2]; +}; + +struct reuse_opts unreusable_opts[12] = { + {0, 0, 0, 0}, + {0, 0, 0, 1}, + {0, 0, 1, 0}, + {0, 0, 1, 1}, + {0, 1, 0, 0}, + {0, 1, 0, 1}, + {0, 1, 1, 0}, + {0, 1, 1, 1}, + {1, 0, 0, 0}, + {1, 0, 0, 1}, + {1, 0, 1, 0}, + {1, 0, 1, 1}, +}; + +struct reuse_opts reusable_opts[4] = { + {1, 1, 0, 0}, + {1, 1, 0, 1}, + {1, 1, 1, 0}, + {1, 1, 1, 1}, +}; + +int bind_port(struct __test_metadata *_metadata, int reuseaddr, int reuseport) +{ + struct sockaddr_in local_addr; + int len = sizeof(local_addr); + int fd, ret; + + fd = socket(AF_INET, SOCK_STREAM, 0); + ASSERT_NE(-1, fd) TH_LOG("failed to open socket."); + + ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &reuseaddr, sizeof(int)); + ASSERT_EQ(0, ret) TH_LOG("failed to setsockopt: SO_REUSEADDR."); + + ret = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &reuseport, sizeof(int)); + ASSERT_EQ(0, ret) TH_LOG("failed to setsockopt: SO_REUSEPORT."); + + local_addr.sin_family = AF_INET; + local_addr.sin_addr.s_addr = inet_addr("127.0.0.1"); + local_addr.sin_port = 0; + + if (bind(fd, (struct sockaddr *)&local_addr, len) == -1) { + close(fd); + return -1; + } + + return fd; +} + +TEST(reuseaddr_ports_exhausted_unreusable) +{ + struct reuse_opts *opts; + int i, j, fd[2]; + + for (i = 0; i < 12; i++) { + opts = &unreusable_opts[i]; + + for (j = 0; j < 2; j++) + fd[j] = bind_port(_metadata, opts->reuseaddr[j], opts->reuseport[j]); + + ASSERT_NE(-1, fd[0]) TH_LOG("failed to bind."); + EXPECT_EQ(-1, fd[1]) TH_LOG("should fail to bind."); + + for (j = 0; j < 2; j++) + if (fd[j] != -1) + close(fd[j]); + } +} + +TEST(reuseaddr_ports_exhausted_reusable_same_euid) +{ + struct reuse_opts *opts; + int i, j, fd[2]; + + for (i = 0; i < 4; i++) { + opts = &reusable_opts[i]; + + for (j = 0; j < 2; j++) + fd[j] = bind_port(_metadata, opts->reuseaddr[j], opts->reuseport[j]); + + ASSERT_NE(-1, fd[0]) TH_LOG("failed to bind."); + + if (opts->reuseport[0] && opts->reuseport[1]) { + EXPECT_EQ(-1, fd[1]) TH_LOG("should fail to bind because both sockets succeed to be listened."); + } else { + EXPECT_NE(-1, fd[1]) TH_LOG("should succeed to bind to connect to different destinations."); + } + + for (j = 0; j < 2; j++) + if (fd[j] != -1) + close(fd[j]); + } +} + +TEST(reuseaddr_ports_exhausted_reusable_different_euid) +{ + struct reuse_opts *opts; + int i, j, ret, fd[2]; + uid_t euid[2] = {10, 20}; + + for (i = 0; i < 4; i++) { + opts = &reusable_opts[i]; + + for (j = 0; j < 2; j++) { + ret = seteuid(euid[j]); + ASSERT_EQ(0, ret) TH_LOG("failed to seteuid: %d.", euid[j]); + + fd[j] = bind_port(_metadata, opts->reuseaddr[j], opts->reuseport[j]); + + ret = seteuid(0); + ASSERT_EQ(0, ret) TH_LOG("failed to seteuid: 0."); + } + + ASSERT_NE(-1, fd[0]) TH_LOG("failed to bind."); + EXPECT_NE(-1, fd[1]) TH_LOG("should succeed to bind because one socket can be bound in each euid."); + + if (fd[1] != -1) { + ret = listen(fd[0], 5); + ASSERT_EQ(0, ret) TH_LOG("failed to listen."); + + ret = listen(fd[1], 5); + EXPECT_EQ(-1, ret) TH_LOG("should fail to listen because only one uid reserves the port in TCP_LISTEN."); + } + + for (j = 0; j < 2; j++) + if (fd[j] != -1) + close(fd[j]); + } +} + +TEST_HARNESS_MAIN diff --git a/tools/testing/selftests/net/reuseaddr_ports_exhausted.sh b/tools/testing/selftests/net/reuseaddr_ports_exhausted.sh new file mode 100755 index 000000000000..20e3a2913d06 --- /dev/null +++ b/tools/testing/selftests/net/reuseaddr_ports_exhausted.sh @@ -0,0 +1,35 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# Run tests when all ephemeral ports are exhausted. +# +# Author: Kuniyuki Iwashima + +set +x +set -e + +readonly NETNS="ns-$(mktemp -u XXXXXX)" + +setup() { + ip netns add "${NETNS}" + ip -netns "${NETNS}" link set lo up + ip netns exec "${NETNS}" \ + sysctl -w net.ipv4.ip_local_port_range="32768 32768" \ + > /dev/null 2>&1 + ip netns exec "${NETNS}" \ + sysctl -w net.ipv4.ip_autobind_reuse=1 > /dev/null 2>&1 +} + +cleanup() { + ip netns del "${NETNS}" +} + +trap cleanup EXIT +setup + +do_test() { + ip netns exec "${NETNS}" ./reuseaddr_ports_exhausted +} + +do_test +echo "tests done"