From 2d7824ffd25ce041db952d713567d54314cb7c29 Mon Sep 17 00:00:00 2001 From: Lorenz Bauer Date: Sun, 29 Mar 2020 15:53:41 -0700 Subject: selftests: bpf: Add test for sk_assign Attach a tc direct-action classifier to lo in a fresh network namespace, and rewrite all connection attempts to localhost:4321 to localhost:1234 (for port tests) and connections to unreachable IPv4/IPv6 IPs to the local socket (for address tests). Includes implementations for both TCP and UDP. Keep in mind that both client to server and server to client traffic passes the classifier. Signed-off-by: Lorenz Bauer Signed-off-by: Joe Stringer Signed-off-by: Alexei Starovoitov Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20200329225342.16317-5-joe@wand.net.nz Co-authored-by: Joe Stringer --- tools/testing/selftests/bpf/prog_tests/sk_assign.c | 276 +++++++++++++++++++++ 1 file changed, 276 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/sk_assign.c (limited to 'tools/testing/selftests/bpf/prog_tests/sk_assign.c') diff --git a/tools/testing/selftests/bpf/prog_tests/sk_assign.c b/tools/testing/selftests/bpf/prog_tests/sk_assign.c new file mode 100644 index 000000000000..25f17fe7d678 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/sk_assign.c @@ -0,0 +1,276 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2018 Facebook +// Copyright (c) 2019 Cloudflare +// Copyright (c) 2020 Isovalent, Inc. +/* + * Test that the socket assign program is able to redirect traffic towards a + * socket, regardless of whether the port or address destination of the traffic + * matches the port. + */ + +#define _GNU_SOURCE +#include +#include +#include +#include + +#include "test_progs.h" + +#define BIND_PORT 1234 +#define CONNECT_PORT 4321 +#define TEST_DADDR (0xC0A80203) +#define NS_SELF "/proc/self/ns/net" + +static const struct timeval timeo_sec = { .tv_sec = 3 }; +static const size_t timeo_optlen = sizeof(timeo_sec); +static int stop, duration; + +static bool +configure_stack(void) +{ + char tc_cmd[BUFSIZ]; + + /* Move to a new networking namespace */ + if (CHECK_FAIL(unshare(CLONE_NEWNET))) + return false; + + /* Configure necessary links, routes */ + if (CHECK_FAIL(system("ip link set dev lo up"))) + return false; + if (CHECK_FAIL(system("ip route add local default dev lo"))) + return false; + if (CHECK_FAIL(system("ip -6 route add local default dev lo"))) + return false; + + /* Load qdisc, BPF program */ + if (CHECK_FAIL(system("tc qdisc add dev lo clsact"))) + return false; + sprintf(tc_cmd, "%s %s %s %s", "tc filter add dev lo ingress bpf", + "direct-action object-file ./test_sk_assign.o", + "section classifier/sk_assign_test", + (env.verbosity < VERBOSE_VERY) ? " 2>/dev/null" : ""); + if (CHECK(system(tc_cmd), "BPF load failed;", + "run with -vv for more info\n")) + return false; + + return true; +} + +static int +start_server(const struct sockaddr *addr, socklen_t len, int type) +{ + int fd; + + fd = socket(addr->sa_family, type, 0); + if (CHECK_FAIL(fd == -1)) + goto out; + if (CHECK_FAIL(setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &timeo_sec, + timeo_optlen))) + goto close_out; + if (CHECK_FAIL(bind(fd, addr, len) == -1)) + goto close_out; + if (CHECK_FAIL(listen(fd, 128) == -1)) + goto close_out; + + goto out; +close_out: + close(fd); + fd = -1; +out: + return fd; +} + +static int +connect_to_server(const struct sockaddr *addr, socklen_t len, int type) +{ + int fd = -1; + + fd = socket(addr->sa_family, type, 0); + if (CHECK_FAIL(fd == -1)) + goto out; + if (CHECK_FAIL(setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &timeo_sec, + timeo_optlen))) + goto close_out; + if (CHECK_FAIL(connect(fd, addr, len))) + goto close_out; + + goto out; +close_out: + close(fd); + fd = -1; +out: + return fd; +} + +static in_port_t +get_port(int fd) +{ + struct sockaddr_storage ss; + socklen_t slen = sizeof(ss); + in_port_t port = 0; + + if (CHECK_FAIL(getsockname(fd, (struct sockaddr *)&ss, &slen))) + return port; + + switch (ss.ss_family) { + case AF_INET: + port = ((struct sockaddr_in *)&ss)->sin_port; + break; + case AF_INET6: + port = ((struct sockaddr_in6 *)&ss)->sin6_port; + break; + default: + CHECK(1, "Invalid address family", "%d\n", ss.ss_family); + } + return port; +} + +static int +run_test(int server_fd, const struct sockaddr *addr, socklen_t len, int type) +{ + int client = -1, srv_client = -1; + char buf[] = "testing"; + in_port_t port; + int ret = 1; + + client = connect_to_server(addr, len, type); + if (client == -1) { + perror("Cannot connect to server"); + goto out; + } + + srv_client = accept(server_fd, NULL, NULL); + if (CHECK_FAIL(srv_client == -1)) { + perror("Can't accept connection"); + goto out; + } + if (CHECK_FAIL(write(client, buf, sizeof(buf)) != sizeof(buf))) { + perror("Can't write on client"); + goto out; + } + if (CHECK_FAIL(read(srv_client, &buf, sizeof(buf)) != sizeof(buf))) { + perror("Can't read on server"); + goto out; + } + + port = get_port(srv_client); + if (CHECK_FAIL(!port)) + goto out; + if (CHECK(port != htons(CONNECT_PORT), "Expected", "port %u but got %u", + CONNECT_PORT, ntohs(port))) + goto out; + + ret = 0; +out: + close(client); + if (srv_client != server_fd) + close(srv_client); + if (ret) + WRITE_ONCE(stop, 1); + return ret; +} + +static void +prepare_addr(struct sockaddr *addr, int family, __u16 port, bool rewrite_addr) +{ + struct sockaddr_in *addr4; + struct sockaddr_in6 *addr6; + + switch (family) { + case AF_INET: + addr4 = (struct sockaddr_in *)addr; + memset(addr4, 0, sizeof(*addr4)); + addr4->sin_family = family; + addr4->sin_port = htons(port); + if (rewrite_addr) + addr4->sin_addr.s_addr = htonl(TEST_DADDR); + else + addr4->sin_addr.s_addr = htonl(INADDR_LOOPBACK); + break; + case AF_INET6: + addr6 = (struct sockaddr_in6 *)addr; + memset(addr6, 0, sizeof(*addr6)); + addr6->sin6_family = family; + addr6->sin6_port = htons(port); + addr6->sin6_addr = in6addr_loopback; + if (rewrite_addr) + addr6->sin6_addr.s6_addr32[3] = htonl(TEST_DADDR); + break; + default: + fprintf(stderr, "Invalid family %d", family); + } +} + +struct test_sk_cfg { + const char *name; + int family; + struct sockaddr *addr; + socklen_t len; + int type; + bool rewrite_addr; +}; + +#define TEST(NAME, FAMILY, TYPE, REWRITE) \ +{ \ + .name = NAME, \ + .family = FAMILY, \ + .addr = (FAMILY == AF_INET) ? (struct sockaddr *)&addr4 \ + : (struct sockaddr *)&addr6, \ + .len = (FAMILY == AF_INET) ? sizeof(addr4) : sizeof(addr6), \ + .type = TYPE, \ + .rewrite_addr = REWRITE, \ +} + +void test_sk_assign(void) +{ + struct sockaddr_in addr4; + struct sockaddr_in6 addr6; + struct test_sk_cfg tests[] = { + TEST("ipv4 tcp port redir", AF_INET, SOCK_STREAM, false), + TEST("ipv4 tcp addr redir", AF_INET, SOCK_STREAM, true), + TEST("ipv6 tcp port redir", AF_INET6, SOCK_STREAM, false), + TEST("ipv6 tcp addr redir", AF_INET6, SOCK_STREAM, true), + }; + int server = -1; + int self_net; + + self_net = open(NS_SELF, O_RDONLY); + if (CHECK_FAIL(self_net < 0)) { + perror("Unable to open "NS_SELF); + return; + } + + if (!configure_stack()) { + perror("configure_stack"); + goto cleanup; + } + + for (int i = 0; i < ARRAY_SIZE(tests) && !READ_ONCE(stop); i++) { + struct test_sk_cfg *test = &tests[i]; + const struct sockaddr *addr; + + if (!test__start_subtest(test->name)) + continue; + prepare_addr(test->addr, test->family, BIND_PORT, false); + addr = (const struct sockaddr *)test->addr; + server = start_server(addr, test->len, test->type); + if (server == -1) + goto cleanup; + + /* connect to unbound ports */ + prepare_addr(test->addr, test->family, CONNECT_PORT, + test->rewrite_addr); + if (run_test(server, addr, test->len, test->type)) + goto close; + + close(server); + server = -1; + } + +close: + close(server); +cleanup: + if (CHECK_FAIL(setns(self_net, CLONE_NEWNET))) + perror("Failed to setns("NS_SELF")"); + close(self_net); +} -- cgit v1.2.3-70-g09d2 From 8a02a1703633e2f954a6d96c12a8375b07309621 Mon Sep 17 00:00:00 2001 From: Joe Stringer Date: Sun, 29 Mar 2020 15:53:42 -0700 Subject: selftests: bpf: Extend sk_assign tests for UDP Add support for testing UDP sk_assign to the existing tests. Signed-off-by: Joe Stringer Signed-off-by: Alexei Starovoitov Acked-by: Lorenz Bauer Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20200329225342.16317-6-joe@wand.net.nz --- tools/testing/selftests/bpf/prog_tests/sk_assign.c | 47 ++++++++++++--- tools/testing/selftests/bpf/progs/test_sk_assign.c | 69 ++++++++++++++++++++-- 2 files changed, 105 insertions(+), 11 deletions(-) (limited to 'tools/testing/selftests/bpf/prog_tests/sk_assign.c') diff --git a/tools/testing/selftests/bpf/prog_tests/sk_assign.c b/tools/testing/selftests/bpf/prog_tests/sk_assign.c index 25f17fe7d678..d572e1a2c297 100644 --- a/tools/testing/selftests/bpf/prog_tests/sk_assign.c +++ b/tools/testing/selftests/bpf/prog_tests/sk_assign.c @@ -69,7 +69,7 @@ start_server(const struct sockaddr *addr, socklen_t len, int type) goto close_out; if (CHECK_FAIL(bind(fd, addr, len) == -1)) goto close_out; - if (CHECK_FAIL(listen(fd, 128) == -1)) + if (type == SOCK_STREAM && CHECK_FAIL(listen(fd, 128) == -1)) goto close_out; goto out; @@ -125,6 +125,20 @@ get_port(int fd) return port; } +static ssize_t +rcv_msg(int srv_client, int type) +{ + struct sockaddr_storage ss; + char buf[BUFSIZ]; + socklen_t slen; + + if (type == SOCK_STREAM) + return read(srv_client, &buf, sizeof(buf)); + else + return recvfrom(srv_client, &buf, sizeof(buf), 0, + (struct sockaddr *)&ss, &slen); +} + static int run_test(int server_fd, const struct sockaddr *addr, socklen_t len, int type) { @@ -139,16 +153,20 @@ run_test(int server_fd, const struct sockaddr *addr, socklen_t len, int type) goto out; } - srv_client = accept(server_fd, NULL, NULL); - if (CHECK_FAIL(srv_client == -1)) { - perror("Can't accept connection"); - goto out; + if (type == SOCK_STREAM) { + srv_client = accept(server_fd, NULL, NULL); + if (CHECK_FAIL(srv_client == -1)) { + perror("Can't accept connection"); + goto out; + } + } else { + srv_client = server_fd; } if (CHECK_FAIL(write(client, buf, sizeof(buf)) != sizeof(buf))) { perror("Can't write on client"); goto out; } - if (CHECK_FAIL(read(srv_client, &buf, sizeof(buf)) != sizeof(buf))) { + if (CHECK_FAIL(rcv_msg(srv_client, type) != sizeof(buf))) { perror("Can't read on server"); goto out; } @@ -156,9 +174,20 @@ run_test(int server_fd, const struct sockaddr *addr, socklen_t len, int type) port = get_port(srv_client); if (CHECK_FAIL(!port)) goto out; - if (CHECK(port != htons(CONNECT_PORT), "Expected", "port %u but got %u", + /* SOCK_STREAM is connected via accept(), so the server's local address + * will be the CONNECT_PORT rather than the BIND port that corresponds + * to the listen socket. SOCK_DGRAM on the other hand is connectionless + * so we can't really do the same check there; the server doesn't ever + * create a socket with CONNECT_PORT. + */ + if (type == SOCK_STREAM && + CHECK(port != htons(CONNECT_PORT), "Expected", "port %u but got %u", CONNECT_PORT, ntohs(port))) goto out; + else if (type == SOCK_DGRAM && + CHECK(port != htons(BIND_PORT), "Expected", + "port %u but got %u", BIND_PORT, ntohs(port))) + goto out; ret = 0; out: @@ -230,6 +259,10 @@ void test_sk_assign(void) TEST("ipv4 tcp addr redir", AF_INET, SOCK_STREAM, true), TEST("ipv6 tcp port redir", AF_INET6, SOCK_STREAM, false), TEST("ipv6 tcp addr redir", AF_INET6, SOCK_STREAM, true), + TEST("ipv4 udp port redir", AF_INET, SOCK_DGRAM, false), + TEST("ipv4 udp addr redir", AF_INET, SOCK_DGRAM, true), + TEST("ipv6 udp port redir", AF_INET6, SOCK_DGRAM, false), + TEST("ipv6 udp addr redir", AF_INET6, SOCK_DGRAM, true), }; int server = -1; int self_net; diff --git a/tools/testing/selftests/bpf/progs/test_sk_assign.c b/tools/testing/selftests/bpf/progs/test_sk_assign.c index 2d9549126e51..8f530843b4da 100644 --- a/tools/testing/selftests/bpf/progs/test_sk_assign.c +++ b/tools/testing/selftests/bpf/progs/test_sk_assign.c @@ -21,7 +21,7 @@ char _license[] SEC("license") = "GPL"; /* Fill 'tuple' with L3 info, and attempt to find L4. On fail, return NULL. */ static inline struct bpf_sock_tuple * -get_tuple(struct __sk_buff *skb, bool *ipv4) +get_tuple(struct __sk_buff *skb, bool *ipv4, bool *tcp) { void *data_end = (void *)(long)skb->data_end; void *data = (void *)(long)skb->data; @@ -60,12 +60,64 @@ get_tuple(struct __sk_buff *skb, bool *ipv4) return (struct bpf_sock_tuple *)data; } - if (result + 1 > data_end || proto != IPPROTO_TCP) + if (proto != IPPROTO_TCP && proto != IPPROTO_UDP) return NULL; + *tcp = (proto == IPPROTO_TCP); return result; } +static inline int +handle_udp(struct __sk_buff *skb, struct bpf_sock_tuple *tuple, bool ipv4) +{ + struct bpf_sock_tuple ln = {0}; + struct bpf_sock *sk; + size_t tuple_len; + int ret; + + tuple_len = ipv4 ? sizeof(tuple->ipv4) : sizeof(tuple->ipv6); + if ((void *)tuple + tuple_len > (void *)(long)skb->data_end) + return TC_ACT_SHOT; + + sk = bpf_sk_lookup_udp(skb, tuple, tuple_len, BPF_F_CURRENT_NETNS, 0); + if (sk) + goto assign; + + if (ipv4) { + if (tuple->ipv4.dport != bpf_htons(4321)) + return TC_ACT_OK; + + ln.ipv4.daddr = bpf_htonl(0x7f000001); + ln.ipv4.dport = bpf_htons(1234); + + sk = bpf_sk_lookup_udp(skb, &ln, sizeof(ln.ipv4), + BPF_F_CURRENT_NETNS, 0); + } else { + if (tuple->ipv6.dport != bpf_htons(4321)) + return TC_ACT_OK; + + /* Upper parts of daddr are already zero. */ + ln.ipv6.daddr[3] = bpf_htonl(0x1); + ln.ipv6.dport = bpf_htons(1234); + + sk = bpf_sk_lookup_udp(skb, &ln, sizeof(ln.ipv6), + BPF_F_CURRENT_NETNS, 0); + } + + /* workaround: We can't do a single socket lookup here, because then + * the compiler will likely spill tuple_len to the stack. This makes it + * lose all bounds information in the verifier, which then rejects the + * call as unsafe. + */ + if (!sk) + return TC_ACT_SHOT; + +assign: + ret = bpf_sk_assign(skb, sk, 0); + bpf_sk_release(sk); + return ret; +} + static inline int handle_tcp(struct __sk_buff *skb, struct bpf_sock_tuple *tuple, bool ipv4) { @@ -130,14 +182,23 @@ int bpf_sk_assign_test(struct __sk_buff *skb) { struct bpf_sock_tuple *tuple, ln = {0}; bool ipv4 = false; + bool tcp = false; int tuple_len; int ret = 0; - tuple = get_tuple(skb, &ipv4); + tuple = get_tuple(skb, &ipv4, &tcp); if (!tuple) return TC_ACT_SHOT; - ret = handle_tcp(skb, tuple, ipv4); + /* Note that the verifier socket return type for bpf_skc_lookup_tcp() + * differs from bpf_sk_lookup_udp(), so even though the C-level type is + * the same here, if we try to share the implementations they will + * fail to verify because we're crossing pointer types. + */ + if (tcp) + ret = handle_tcp(skb, tuple, ipv4); + else + ret = handle_udp(skb, tuple, ipv4); return ret == 0 ? TC_ACT_OK : TC_ACT_SHOT; } -- cgit v1.2.3-70-g09d2