From: Mohammad Nassiri mnassiri@ciena.com

The end_server() function only operates in the server thread and always takes an accept socket instead of a listen socket as its input argument. To align with this, invert the boolean values used when calling verify_counters() within the end_server() function.

As a result of this typo, the test didn't correctly check for the non-symmetrical scenario, where i.e. peer-A uses a key <100:200> to send data, but peer-B uses another key <105:205> to send its data. So, in simple words, different keys for TX and RX.

Fixes: 3c3ead555648 ("selftests/net: Add TCP-AO key-management test") Signed-off-by: Mohammad Nassiri mnassiri@ciena.com Link: https://lore.kernel.org/all/934627c5-eebb-4626-be23-cfb134c01d1a@arista.com/ [amended 'Fixes' tag, added the issue description and carried-over to lkml] Signed-off-by: Dmitry Safonov dima@arista.com --- tools/testing/selftests/net/tcp_ao/key-management.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/tcp_ao/key-management.c b/tools/testing/selftests/net/tcp_ao/key-management.c index c48b4970ca17..f6a9395e3cd7 100644 --- a/tools/testing/selftests/net/tcp_ao/key-management.c +++ b/tools/testing/selftests/net/tcp_ao/key-management.c @@ -843,7 +843,7 @@ static void end_server(const char *tst_name, int sk, synchronize_threads(); /* 4: verified => closed */ close(sk);

- verify_counters(tst_name, true, false, begin, &end); + verify_counters(tst_name, false, true, begin, &end); synchronize_threads(); /* 5: counters */ }

Currently, the test is racy and seems to not pass anymore.

In order to rectify it, aim on TCP_TW_RST. Doesn't seem way too good with this sleep() part, but it seems as a reasonable compromise for the test. There is a plan in-line comment on how-to improve it, going to do it on the top, at this moment I want it to run on netdev/patchwork selftests dashboard.

It also slightly changes tcp_ao-lib in order to get SO_ERROR propagated to test_client_verify() return value.

Fixes: c6df7b2361d7 ("selftests/net: Add TCP-AO RST test") Signed-off-by: Dmitry Safonov dima@arista.com --- tools/testing/selftests/net/tcp_ao/lib/sock.c | 12 ++- tools/testing/selftests/net/tcp_ao/rst.c | 138 +++++++++++++++++--------- 2 files changed, 98 insertions(+), 52 deletions(-)

diff --git a/tools/testing/selftests/net/tcp_ao/lib/sock.c b/tools/testing/selftests/net/tcp_ao/lib/sock.c index c75d82885a2e..15aeb0963058 100644 --- a/tools/testing/selftests/net/tcp_ao/lib/sock.c +++ b/tools/testing/selftests/net/tcp_ao/lib/sock.c @@ -62,7 +62,9 @@ int test_wait_fd(int sk, time_t sec, bool write) return -ETIMEDOUT; }

- if (getsockopt(sk, SOL_SOCKET, SO_ERROR, &ret, &slen) || ret) + if (getsockopt(sk, SOL_SOCKET, SO_ERROR, &ret, &slen)) + return -errno; + if (ret) return -ret; return 0; } @@ -584,9 +586,11 @@ int test_client_verify(int sk, const size_t msg_len, const size_t nr, { size_t buf_sz = msg_len * nr; char *buf = alloca(buf_sz); + ssize_t ret;

randomize_buffer(buf, buf_sz); - if (test_client_loop(sk, buf, buf_sz, msg_len, timeout_sec) != buf_sz) - return -1; - return 0; + ret = test_client_loop(sk, buf, buf_sz, msg_len, timeout_sec); + if (ret < 0) + return (int)ret; + return ret != buf_sz ? -1 : 0; } diff --git a/tools/testing/selftests/net/tcp_ao/rst.c b/tools/testing/selftests/net/tcp_ao/rst.c index ac06009a7f5f..7df8b8700e39 100644 --- a/tools/testing/selftests/net/tcp_ao/rst.c +++ b/tools/testing/selftests/net/tcp_ao/rst.c @@ -1,10 +1,33 @@ // SPDX-License-Identifier: GPL-2.0 -/* Author: Dmitry Safonov dima@arista.com */ +/* + * The test checks that both active and passive reset have correct TCP-AO + * signature. An "active" reset (abort) here is procured from closing + * listen() socket with non-accepted connections in the queue: + * inet_csk_listen_stop() => inet_child_forget() => + * => tcp_disconnect() => tcp_send_active_reset() + * + * The passive reset is quite hard to get on established TCP connections. + * It could be procured from non-established states, but the synchronization + * part from userspace in order to reliably get RST seems uneasy. + * So, instead it's procured by corrupting SEQ number on TIMED-WAIT state. + * + * It's important to test both passive and active RST as they go through + * different code-paths: + * - tcp_send_active_reset() makes no-data skb, sends it with tcp_transmit_skb() + * - tcp_v*_send_reset() create their reply skbs and send them with + * ip_send_unicast_reply() + * + * In both cases TCP-AO signatures have to be correct, which is verified by + * (1) checking that the TCP-AO connection was reset and (2) TCP-AO counters. + * + * Author: Dmitry Safonov dima@arista.com + */ #include <inttypes.h> #include "../../../../include/linux/kernel.h" #include "aolib.h"

const size_t quota = 1000; +const size_t packet_sz = 100; /* * Backlog == 0 means 1 connection in queue, see: * commit 64a146513f8f ("[NET]: Revert incorrect accept queue...") @@ -59,26 +82,6 @@ static void close_forced(int sk) close(sk); }

-static int test_wait_for_exception(int sk, time_t sec) -{ - struct timeval tv = { .tv_sec = sec }; - struct timeval *ptv = NULL; - fd_set efds; - int ret; - - FD_ZERO(&efds); - FD_SET(sk, &efds); - - if (sec) - ptv = &tv; - - errno = 0; - ret = select(sk + 1, NULL, NULL, &efds, ptv); - if (ret < 0) - return -errno; - return ret ? sk : 0; -} - static void test_server_active_rst(unsigned int port) { struct tcp_ao_counters cnt1, cnt2; @@ -155,17 +158,16 @@ static void test_server_passive_rst(unsigned int port) test_fail("server returned %zd", bytes); }

- synchronize_threads(); /* 3: chekpoint/restore the connection */ + synchronize_threads(); /* 3: checkpoint the client */ + synchronize_threads(); /* 4: close the server, creating twsk */ if (test_get_tcp_ao_counters(sk, &ao2)) test_error("test_get_tcp_ao_counters()"); - - synchronize_threads(); /* 4: terminate server + send more on client */ - bytes = test_server_run(sk, quota, TEST_RETRANSMIT_SEC); close(sk); + + synchronize_threads(); /* 5: restore the socket, send more data */ test_tcp_ao_counters_cmp("passive RST server", &ao1, &ao2, TEST_CNT_GOOD);

- synchronize_threads(); /* 5: verified => closed */ - close(sk); + synchronize_threads(); /* 6: server exits */ }

static void *server_fn(void *arg) @@ -284,7 +286,7 @@ static void test_client_active_rst(unsigned int port) test_error("test_wait_fds(): %d", err);

synchronize_threads(); /* 3: close listen socket */ - if (test_client_verify(sk[0], 100, quota / 100, TEST_TIMEOUT_SEC)) + if (test_client_verify(sk[0], packet_sz, quota / packet_sz, TEST_TIMEOUT_SEC)) test_fail("Failed to send data on connected socket"); else test_ok("Verified established tcp connection"); @@ -323,7 +325,6 @@ static void test_client_passive_rst(unsigned int port) struct tcp_sock_state img; sockaddr_af saddr; int sk, err; - socklen_t slen = sizeof(err);

sk = socket(test_family, SOCK_STREAM, IPPROTO_TCP); if (sk < 0) @@ -337,18 +338,51 @@ static void test_client_passive_rst(unsigned int port) test_error("failed to connect()");

synchronize_threads(); /* 2: accepted => send data */ - if (test_client_verify(sk, 100, quota / 100, TEST_TIMEOUT_SEC)) + if (test_client_verify(sk, packet_sz, quota / packet_sz, TEST_TIMEOUT_SEC)) test_fail("Failed to send data on connected socket"); else test_ok("Verified established tcp connection");

- synchronize_threads(); /* 3: chekpoint/restore the connection */ + synchronize_threads(); /* 3: checkpoint the client */ test_enable_repair(sk); test_sock_checkpoint(sk, &img, &saddr); test_ao_checkpoint(sk, &ao_img); - test_kill_sk(sk); + test_disable_repair(sk);

- img.out.seq += quota; + synchronize_threads(); /* 4: close the server, creating twsk */ + + /* + * The "corruption" in SEQ has to be small enough to fit into TCP + * window, see tcp_timewait_state_process() for out-of-window + * segments. + */ + img.out.seq += 5; /* 5 is more noticeable in tcpdump than 1 */ + + /* + * FIXME: This is kind-of ugly and dirty, but it works. + * + * At this moment, the server has close'ed(sk). + * The passive RST that is being targeted here is new data after + * half-duplex close, see tcp_timewait_state_process() => TCP_TW_RST + * + * What is needed here is: + * (1) wait for FIN from the server + * (2) make sure that the ACK from the client went out + * (3) make sure that the ACK was received and processed by the server + * + * Otherwise, the data that will be sent from "repaired" socket + * post SEQ corruption may get to the server before it's in + * TCP_FIN_WAIT2. + * + * (1) is easy with select()/poll() + * (2) is possible by polling tcpi_state from TCP_INFO + * (3) is quite complex: as server's socket was already closed, + * probably the way to do it would be tcp-diag. + */ + sleep(TEST_RETRANSMIT_SEC); + + synchronize_threads(); /* 5: restore the socket, send more data */ + test_kill_sk(sk);

sk = socket(test_family, SOCK_STREAM, IPPROTO_TCP); if (sk < 0) @@ -366,25 +400,33 @@ static void test_client_passive_rst(unsigned int port) test_disable_repair(sk); test_sock_state_free(&img);

- synchronize_threads(); /* 4: terminate server + send more on client */ - if (test_client_verify(sk, 100, quota / 100, 2 * TEST_TIMEOUT_SEC)) - test_ok("client connection broken post-seq-adjust"); + /* + * This is how "passive reset" is acquired in this test from TCP_TW_RST: + * + * IP 10.0.254.1.7011 > 10.0.1.1.59772: Flags [P.], seq 901:1001, ack 1001, win 249, + * options [tcp-ao keyid 100 rnextkeyid 100 mac 0x10217d6c36a22379086ef3b1], length 100 + * IP 10.0.254.1.7011 > 10.0.1.1.59772: Flags [F.], seq 1001, ack 1001, win 249, + * options [tcp-ao keyid 100 rnextkeyid 100 mac 0x104ffc99b98c10a5298cc268], length 0 + * IP 10.0.1.1.59772 > 10.0.254.1.7011: Flags [.], ack 1002, win 251, + * options [tcp-ao keyid 100 rnextkeyid 100 mac 0xe496dd4f7f5a8a66873c6f93,nop,nop,sack 1 {1001:1002}], length 0 + * IP 10.0.1.1.59772 > 10.0.254.1.7011: Flags [P.], seq 1006:1106, ack 1001, win 251, + * options [tcp-ao keyid 100 rnextkeyid 100 mac 0x1b5f3330fb23fbcd0c77d0ca], length 100 + * IP 10.0.254.1.7011 > 10.0.1.1.59772: Flags [R], seq 3215596252, win 0, + * options [tcp-ao keyid 100 rnextkeyid 100 mac 0x0bcfbbf497bce844312304b2], length 0 + */ + err = test_client_verify(sk, packet_sz, quota / packet_sz, 2 * TEST_TIMEOUT_SEC); + /* Make sure that the connection was reset, not timeouted */ + if (err && err == -ECONNRESET) + test_ok("client sock was passively reset post-seq-adjust"); + else if (err) + test_fail("client sock was not reset post-seq-adjust: %d", err); else - test_fail("client connection still works post-seq-adjust"); - - test_wait_for_exception(sk, TEST_TIMEOUT_SEC); - - if (getsockopt(sk, SOL_SOCKET, SO_ERROR, &err, &slen)) - test_error("getsockopt()"); - if (err != ECONNRESET && err != EPIPE) - test_fail("client connection was not reset: %d", err); - else - test_ok("client connection was reset"); + test_fail("client sock is yet connected post-seq-adjust");

if (test_get_tcp_ao_counters(sk, &ao2)) test_error("test_get_tcp_ao_counters()");

- synchronize_threads(); /* 5: verified => closed */ + synchronize_threads(); /* 6: server exits */ close(sk); test_tcp_ao_counters_cmp("client passive RST", &ao1, &ao2, TEST_CNT_GOOD); } @@ -410,6 +452,6 @@ static void *client_fn(void *arg)

int main(int argc, char *argv[]) { - test_init(15, server_fn, client_fn); + test_init(14, server_fn, client_fn); return 0; }