From 8fb5bb169d17cdd12c2dcc2e96830ed487d77a0f Mon Sep 17 00:00:00 2001 From: Michal Luczaj Date: Thu, 13 Feb 2025 12:58:49 +0100 Subject: [PATCH 1/4] sockmap, vsock: For connectible sockets allow only connected sockmap expects all vsocks to have a transport assigned, which is expressed in vsock_proto::psock_update_sk_prot(). However, there is an edge case where an unconnected (connectible) socket may lose its previously assigned transport. This is handled with a NULL check in the vsock/BPF recv path. Another design detail is that listening vsocks are not supposed to have any transport assigned at all. Which implies they are not supported by the sockmap. But this is complicated by the fact that a socket, before switching to TCP_LISTEN, may have had some transport assigned during a failed connect() attempt. Hence, we may end up with a listening vsock in a sockmap, which blows up quickly: KASAN: null-ptr-deref in range [0x0000000000000120-0x0000000000000127] CPU: 7 UID: 0 PID: 56 Comm: kworker/7:0 Not tainted 6.14.0-rc1+ Workqueue: vsock-loopback vsock_loopback_work RIP: 0010:vsock_read_skb+0x4b/0x90 Call Trace: sk_psock_verdict_data_ready+0xa4/0x2e0 virtio_transport_recv_pkt+0x1ca8/0x2acc vsock_loopback_work+0x27d/0x3f0 process_one_work+0x846/0x1420 worker_thread+0x5b3/0xf80 kthread+0x35a/0x700 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x1a/0x30 For connectible sockets, instead of relying solely on the state of vsk->transport, tell sockmap to only allow those representing established connections. This aligns with the behaviour for AF_INET and AF_UNIX. Fixes: 634f1a7110b4 ("vsock: support sockmap") Signed-off-by: Michal Luczaj Acked-by: Stefano Garzarella Signed-off-by: Paolo Abeni --- net/core/sock_map.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/core/sock_map.c b/net/core/sock_map.c index f1b9b3958792..2f1be9baad05 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -541,6 +541,9 @@ static bool sock_map_sk_state_allowed(const struct sock *sk) return (1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_LISTEN); if (sk_is_stream_unix(sk)) return (1 << sk->sk_state) & TCPF_ESTABLISHED; + if (sk_is_vsock(sk) && + (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) + return (1 << sk->sk_state) & TCPF_ESTABLISHED; return true; } From 857ae05549ee2542317e7084ecaa5f8536634dd9 Mon Sep 17 00:00:00 2001 From: Michal Luczaj Date: Thu, 13 Feb 2025 12:58:50 +0100 Subject: [PATCH 2/4] vsock/bpf: Warn on socket without transport In the spirit of commit 91751e248256 ("vsock: prevent null-ptr-deref in vsock_*[has_data|has_space]"), armorize the "impossible" cases with a warning. Fixes: 634f1a7110b4 ("vsock: support sockmap") Signed-off-by: Michal Luczaj Reviewed-by: Stefano Garzarella Signed-off-by: Paolo Abeni --- net/vmw_vsock/af_vsock.c | 3 +++ net/vmw_vsock/vsock_bpf.c | 2 +- 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index 53a081d49d28..7e3db87ae433 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -1189,6 +1189,9 @@ static int vsock_read_skb(struct sock *sk, skb_read_actor_t read_actor) { struct vsock_sock *vsk = vsock_sk(sk); + if (WARN_ON_ONCE(!vsk->transport)) + return -ENODEV; + return vsk->transport->read_skb(vsk, read_actor); } diff --git a/net/vmw_vsock/vsock_bpf.c b/net/vmw_vsock/vsock_bpf.c index f201d9eca1df..07b96d56f3a5 100644 --- a/net/vmw_vsock/vsock_bpf.c +++ b/net/vmw_vsock/vsock_bpf.c @@ -87,7 +87,7 @@ static int vsock_bpf_recvmsg(struct sock *sk, struct msghdr *msg, lock_sock(sk); vsk = vsock_sk(sk); - if (!vsk->transport) { + if (WARN_ON_ONCE(!vsk->transport)) { copied = -ENODEV; goto out; } From 8350695bfb169b1924626a68f76b369ad01f18f2 Mon Sep 17 00:00:00 2001 From: Michal Luczaj Date: Thu, 13 Feb 2025 12:58:51 +0100 Subject: [PATCH 3/4] selftest/bpf: Adapt vsock_delete_on_close to sockmap rejecting unconnected Commit 515745445e92 ("selftest/bpf: Add test for vsock removal from sockmap on close()") added test that checked if proto::close() callback was invoked on AF_VSOCK socket release. I.e. it verified that a close()d vsock does indeed get removed from the sockmap. It was done simply by creating a socket pair and attempting to replace a close()d one with its peer. Since, due to a recent change, sockmap does not allow updating index with a non-established connectible vsock, redo it with a freshly established one. Signed-off-by: Michal Luczaj Acked-by: Stefano Garzarella Signed-off-by: Paolo Abeni --- .../selftests/bpf/prog_tests/sockmap_basic.c | 40 ++++++++++--------- 1 file changed, 22 insertions(+), 18 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c index 884ad87783d5..21793d8c79e1 100644 --- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c @@ -111,31 +111,35 @@ out: static void test_sockmap_vsock_delete_on_close(void) { - int err, c, p, map; - const int zero = 0; - - err = create_pair(AF_VSOCK, SOCK_STREAM, &c, &p); - if (!ASSERT_OK(err, "create_pair(AF_VSOCK)")) - return; + int map, c, p, err, zero = 0; map = bpf_map_create(BPF_MAP_TYPE_SOCKMAP, NULL, sizeof(int), sizeof(int), 1, NULL); - if (!ASSERT_GE(map, 0, "bpf_map_create")) { - close(c); - goto out; - } + if (!ASSERT_OK_FD(map, "bpf_map_create")) + return; + + err = create_pair(AF_VSOCK, SOCK_STREAM, &c, &p); + if (!ASSERT_OK(err, "create_pair")) + goto close_map; + + if (xbpf_map_update_elem(map, &zero, &c, BPF_NOEXIST)) + goto close_socks; + + xclose(c); + xclose(p); + + err = create_pair(AF_VSOCK, SOCK_STREAM, &c, &p); + if (!ASSERT_OK(err, "create_pair")) + goto close_map; err = bpf_map_update_elem(map, &zero, &c, BPF_NOEXIST); - close(c); - if (!ASSERT_OK(err, "bpf_map_update")) - goto out; - - err = bpf_map_update_elem(map, &zero, &p, BPF_NOEXIST); ASSERT_OK(err, "after close(), bpf_map_update"); -out: - close(p); - close(map); +close_socks: + xclose(c); + xclose(p); +close_map: + xclose(map); } static void test_skmsg_helpers(enum bpf_map_type map_type) From 85928e9c436398abcac32a9afa2f591895dd497d Mon Sep 17 00:00:00 2001 From: Michal Luczaj Date: Thu, 13 Feb 2025 12:58:52 +0100 Subject: [PATCH 4/4] selftest/bpf: Add vsock test for sockmap rejecting unconnected Verify that for a connectible AF_VSOCK socket, merely having a transport assigned is insufficient; socket must be connected for the sockmap to accept. This does not test datagram vsocks. Even though it hardly matters. VMCI is the only transport that features VSOCK_TRANSPORT_F_DGRAM, but it has an unimplemented vsock_transport::readskb() callback, making it unsupported by BPF/sockmap. Signed-off-by: Michal Luczaj Acked-by: Stefano Garzarella Signed-off-by: Paolo Abeni --- .../selftests/bpf/prog_tests/sockmap_basic.c | 30 +++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c index 21793d8c79e1..05eb37935c3e 100644 --- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c @@ -1065,6 +1065,34 @@ destroy: test_sockmap_pass_prog__destroy(skel); } +static void test_sockmap_vsock_unconnected(void) +{ + struct sockaddr_storage addr; + int map, s, zero = 0; + socklen_t alen; + + map = bpf_map_create(BPF_MAP_TYPE_SOCKMAP, NULL, sizeof(int), + sizeof(int), 1, NULL); + if (!ASSERT_OK_FD(map, "bpf_map_create")) + return; + + s = xsocket(AF_VSOCK, SOCK_STREAM, 0); + if (s < 0) + goto close_map; + + /* Fail connect(), but trigger transport assignment. */ + init_addr_loopback(AF_VSOCK, &addr, &alen); + if (!ASSERT_ERR(connect(s, sockaddr(&addr), alen), "connect")) + goto close_sock; + + ASSERT_ERR(bpf_map_update_elem(map, &zero, &s, BPF_ANY), "map_update"); + +close_sock: + xclose(s); +close_map: + xclose(map); +} + void test_sockmap_basic(void) { if (test__start_subtest("sockmap create_update_free")) @@ -1131,4 +1159,6 @@ void test_sockmap_basic(void) test_skmsg_helpers_with_link(BPF_MAP_TYPE_SOCKHASH); if (test__start_subtest("sockmap skb_verdict vsock poll")) test_sockmap_skb_verdict_vsock_poll(); + if (test__start_subtest("sockmap vsock unconnected")) + test_sockmap_vsock_unconnected(); }