From patchwork Sun Mar 16 22:45:06 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michal Luczaj X-Patchwork-Id: 14018541 Received: from mailtransmit05.runbox.com (mailtransmit05.runbox.com [185.226.149.38]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BA9AA4A32; Sun, 16 Mar 2025 22:46:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.226.149.38 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742165167; cv=none; b=rXGZhPYXhGn6N7Iwb+ebnTVIu3MmoxJACVr0hSta3Bzq47ZbxK6mIQf0/yq8zQQSsI/hlwUlwaI6GtZ/vYW6Rqd+UTa/h+9HC88QGtFMborfP9rSke+KElWB3NX8k6r/NkvTX9isJibX2Pae6FSx4VUjBZdL2s/KG9yu7FYy2iA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742165167; c=relaxed/simple; bh=3tj+sd1hBSK0PpyiKGpyyTMF/4GJvPBwbGnV9vwWXd0=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=iX374H7CE5K4qmt2gdFkgmydQ7fh0mevX9tAc/OerDrfzAaLDbjOrE57yEoCXROkiqpXUdb8bzFm+/mOTNB1UIb4q+M3thJE26XYB2zvzH55EVSTMPuNfHgR77fnwJqIkMq8bl0Ev/bz0G/zdA4lVvUAxtEKAnhXHM3A+/RIjfs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rbox.co; spf=pass smtp.mailfrom=rbox.co; dkim=pass (2048-bit key) header.d=rbox.co header.i=@rbox.co header.b=MEOB1mNv; arc=none smtp.client-ip=185.226.149.38 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rbox.co Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rbox.co Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=rbox.co header.i=@rbox.co header.b="MEOB1mNv" Received: from mailtransmit03.runbox ([10.9.9.163] helo=aibo.runbox.com) by mailtransmit05.runbox.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1ttwjt-00CYL9-TD; Sun, 16 Mar 2025 23:45:49 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=rbox.co; s=selector1; h=Cc:To:In-Reply-To:References:Message-Id: Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date:From; bh=bxiMFSV63H5IMVOHX04yoU+77ubhpH+TthNc1KSiRUY=; b=MEOB1mNv8upfTIyCtq6gr4Uz/u Vf0Mu3FRnLEAvUJFt0AdeoB25lxmr8BWdk1GIE2oyKD3i4Pz+TWPqiHfBaaUF/hhUDBPwaMuXoHyN TJfGq64rRtfKfMsOwcIozkUq1u9tPPjyISftVhZU3XXvNbMhIYEHyE3+ws5FeqjoxSooykEuZDZSq HDi+//XbRPEbstpx7Oo6ad0SexifaFSHA8xIHRmpDrLMwdHl8q/LgU4ODZatuSypUgHSNvKw+k2V2 SkuOIy9zcgYgNS0wX/Pwel9IviflUmhm9IwhnWfV2bgWRDMuk6gKF413Mm14Vrj+/HZJbiwHxUbwt DuZZu+Ww==; Received: from [10.9.9.74] (helo=submission03.runbox) by mailtransmit03.runbox with esmtp (Exim 4.86_2) (envelope-from ) id 1ttwjs-0000eH-ML; Sun, 16 Mar 2025 23:45:48 +0100 Received: by submission03.runbox with esmtpsa [Authenticated ID (604044)] (TLS1.2:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.93) id 1ttwjp-00AYw2-7u; Sun, 16 Mar 2025 23:45:45 +0100 From: Michal Luczaj Date: Sun, 16 Mar 2025 23:45:06 +0100 Subject: [PATCH net v3 1/3] vsock/bpf: Fix EINTR connect() racing sockmap update Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250316-vsock-trans-signal-race-v3-1-17a6862277c9@rbox.co> References: <20250316-vsock-trans-signal-race-v3-0-17a6862277c9@rbox.co> In-Reply-To: <20250316-vsock-trans-signal-race-v3-0-17a6862277c9@rbox.co> To: Stefano Garzarella , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , "Michael S. Tsirkin" , Bobby Eshleman , Andrii Nakryiko , Eduard Zingerman , Mykola Lysenko , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shuah Khan Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Michal Luczaj X-Mailer: b4 0.14.2 Signal delivery during connect() may result in a disconnect of an already TCP_ESTABLISHED socket. Problem is that such established socket might have been placed in a sockmap before the connection was closed. We end up with a SS_UNCONNECTED vsock in a sockmap. And this, combined with the ability to reassign (unconnected) vsock's transport to NULL, breaks the sockmap contract. As manifested by WARN_ON_ONCE. connect / state = SS_CONNECTED / sock_map_update_elem if signal_pending state = SS_UNCONNECTED connect transport = NULL vsock_bpf_recvmsg WARN_ON_ONCE(!vsk->transport) Ensure the socket does not stay in sockmap. WARNING: CPU: 8 PID: 1228 at net/vmw_vsock/vsock_bpf.c:97 vsock_bpf_recvmsg+0xb43/0xe00 CPU: 8 UID: 0 PID: 1228 Comm: a.out Not tainted 6.14.0-rc5+ RIP: 0010:vsock_bpf_recvmsg+0xb43/0xe00 sock_recvmsg+0x1b2/0x220 __sys_recvfrom+0x190/0x270 __x64_sys_recvfrom+0xdc/0x1b0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Fixes: 634f1a7110b4 ("vsock: support sockmap") Reviewed-by: Stefano Garzarella Signed-off-by: Michal Luczaj --- net/vmw_vsock/af_vsock.c | 10 +++++++++- net/vmw_vsock/vsock_bpf.c | 1 + 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index 7e3db87ae4333cf63327ec105ca99253569bb9fe..81b1b8e9c946a646778367ab78ca180cef75ef72 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -1579,7 +1579,15 @@ static int vsock_connect(struct socket *sock, struct sockaddr *addr, if (signal_pending(current)) { err = sock_intr_errno(timeout); - sk->sk_state = sk->sk_state == TCP_ESTABLISHED ? TCP_CLOSING : TCP_CLOSE; + if (sk->sk_state == TCP_ESTABLISHED) { + /* Might have raced with a sockmap update. */ + if (sk->sk_prot->unhash) + sk->sk_prot->unhash(sk); + + sk->sk_state = TCP_CLOSING; + } else { + sk->sk_state = TCP_CLOSE; + } sock->state = SS_UNCONNECTED; vsock_transport_cancel_pkt(vsk); vsock_remove_connected(vsk); diff --git a/net/vmw_vsock/vsock_bpf.c b/net/vmw_vsock/vsock_bpf.c index 07b96d56f3a577af71021b1b8132743554996c4f..c68fdaf09046b68254dac3ea70ffbe73dfa45cef 100644 --- a/net/vmw_vsock/vsock_bpf.c +++ b/net/vmw_vsock/vsock_bpf.c @@ -127,6 +127,7 @@ static void vsock_bpf_rebuild_protos(struct proto *prot, const struct proto *bas { *prot = *base; prot->close = sock_map_close; + prot->unhash = sock_map_unhash; prot->recvmsg = vsock_bpf_recvmsg; prot->sock_is_readable = sk_msg_is_readable; } From patchwork Sun Mar 16 22:45:07 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michal Luczaj X-Patchwork-Id: 14018543 Received: from mailtransmit05.runbox.com (mailtransmit05.runbox.com [185.226.149.38]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DBD781A0728; Sun, 16 Mar 2025 22:46:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.226.149.38 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742165176; cv=none; b=s1I5Vo2+lhhNVbSzc4AfAAv9OkSbmYWEv4z+Gy215GdhnsU/82lGE+i/mmmU/Z87zwvTl2vSz+EnUQkJRzQK/7PqD/Jy+jJylDat6s1dUB72YcM3pKRIrNK5jzsePo8D9hDG8iUaMHjECSj+CS5v+Q6nI84gODsUE8ULTk/35Yg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742165176; c=relaxed/simple; bh=0Vuf4A7KemEmnxE1amJ/cuggcFCMtABwslfDy2lyxls=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=j0AITSBEYf+Gx24MaWoj0Ls45gniJkbbKvBUz1WLpgC0y91iS2lAbmAA5rGSEYO2CVIsJ5zKh7OWnEWsKoX6Vxl5c1LUzcbhvsuUbBPTBsE+HO9TKVhD2Tw7kGZqnZYHnQRTeH3RmsOfgTcx496Z5AJweFa7Jfk/htEaSKzHTDE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rbox.co; spf=pass smtp.mailfrom=rbox.co; dkim=pass (2048-bit key) header.d=rbox.co header.i=@rbox.co header.b=aQOdWHZD; arc=none smtp.client-ip=185.226.149.38 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rbox.co Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rbox.co Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=rbox.co header.i=@rbox.co header.b="aQOdWHZD" Received: from mailtransmit03.runbox ([10.9.9.163] helo=aibo.runbox.com) by mailtransmit05.runbox.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1ttwkE-00CYQb-Fz; Sun, 16 Mar 2025 23:46:10 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=rbox.co; s=selector1; h=Cc:To:In-Reply-To:References:Message-Id: Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date:From; bh=Ju1FMTCjLE06/FL0/l7ykej6UKINCh4tTv7Js5hjLtQ=; b=aQOdWHZDgzVbdI2DzUXvS+cZzr uKm0rSnpFbjeClXOTir8h3uGMpDFMDFtj4Mdua1Yfmt3rX0e1PbtkdPNBZQkiVO+fw5G5n+fOqk6j yhFPSUq1sKW/3UnlFfZgXj9OEBtZgJdazlvidi9Rpd16BNBTQnOfhUojTiCisGb08WMMW1C/betba Qp6uD0M+SDmU5J0RQ6tKgQdZmfXfidbgAcS7EOAmYXM+WIkcUFFHsBkSyRsXYCgWMH6ljCE5zQ5MR eHOlj48kk3aA0w1mwKE0cNfht84TixosaQvZEpREFspXFvLO5mbHd3Y4BZOv5+uImlLKQ6HyybSSV d9YiacmA==; Received: from [10.9.9.74] (helo=submission03.runbox) by mailtransmit03.runbox with esmtp (Exim 4.86_2) (envelope-from ) id 1ttwkE-0000fn-4V; Sun, 16 Mar 2025 23:46:10 +0100 Received: by submission03.runbox with esmtpsa [Authenticated ID (604044)] (TLS1.2:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.93) id 1ttwjq-00AYw2-Eh; Sun, 16 Mar 2025 23:45:46 +0100 From: Michal Luczaj Date: Sun, 16 Mar 2025 23:45:07 +0100 Subject: [PATCH net v3 2/3] selftest/bpf: Add test for AF_VSOCK connect() racing sockmap update Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250316-vsock-trans-signal-race-v3-2-17a6862277c9@rbox.co> References: <20250316-vsock-trans-signal-race-v3-0-17a6862277c9@rbox.co> In-Reply-To: <20250316-vsock-trans-signal-race-v3-0-17a6862277c9@rbox.co> To: Stefano Garzarella , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , "Michael S. Tsirkin" , Bobby Eshleman , Andrii Nakryiko , Eduard Zingerman , Mykola Lysenko , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shuah Khan Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Michal Luczaj X-Mailer: b4 0.14.2 Racing signal-interrupted connect() and sockmap update may result in an unconnected (and missing vsock transport) socket in a sockmap. Test spends 2 seconds attempting to reach WARN_ON_ONCE(). connect / state = SS_CONNECTED / sock_map_update_elem if signal_pending state = SS_UNCONNECTED connect transport = NULL vsock_bpf_recvmsg WARN_ON_ONCE(!vsk->transport) Signed-off-by: Michal Luczaj --- .../selftests/bpf/prog_tests/sockmap_basic.c | 97 ++++++++++++++++++++++ 1 file changed, 97 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c index 1e3e4392dcca0e1722c1982ecc649a80c27443b2..d9cd20d1fbc25cc56d37f06522c5b805004fa884 100644 --- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c @@ -3,6 +3,7 @@ #include #include #include +#include #include "test_progs.h" #include "test_skmsg_load_helpers.skel.h" @@ -1042,6 +1043,100 @@ static void test_sockmap_vsock_unconnected(void) xclose(map); } +#define CONNECT_SIGNAL_RACE_TIMEOUT 2 /* seconds */ + +static void sig_handler(int signum) +{ + /* nop */ +} + +static void connect_signal_racer_cleanup(void *map) +{ + xclose(*(int *)map); +} + +static void *connect_signal_racer(void *arg) +{ + int map; + + map = bpf_map_create(BPF_MAP_TYPE_SOCKMAP, NULL, sizeof(int), + sizeof(int), 1, NULL); + if (!ASSERT_OK_FD(map, "bpf_map_create")) + return NULL; + + pthread_cleanup_push(connect_signal_racer_cleanup, &map); + + for (;;) { + int c = *(int *)arg; + int zero = 0; + + (void)bpf_map_update_elem(map, &zero, &c, BPF_ANY); + + if (kill(0, SIGUSR1)) { + FAIL_ERRNO("kill"); + break; + } + + if ((recv(c, NULL, 0, MSG_DONTWAIT) < 0) && errno == ENODEV) { + FAIL_ERRNO("recv"); + break; + } + } + + pthread_cleanup_pop(1); + + return NULL; +} + +static void test_sockmap_vsock_connect_signal_race(void) +{ + struct sockaddr_vm addr, bad_addr; + socklen_t alen = sizeof(addr); + sighandler_t orig_handler; + pthread_t thread; + int s, c, p; + __u64 tout; + + orig_handler = signal(SIGUSR1, sig_handler); + if (!ASSERT_NEQ(orig_handler, SIG_ERR, "signal handler setup")) + return; + + s = socket_loopback(AF_VSOCK, SOCK_SEQPACKET | SOCK_NONBLOCK); + if (s < 0) + goto restore; + + if (xgetsockname(s, (struct sockaddr *)&addr, &alen)) + goto close; + + bad_addr = addr; + bad_addr.svm_cid = 0x42424242; /* non-existing */ + + if (xpthread_create(&thread, 0, connect_signal_racer, &c)) + goto close; + + tout = get_time_ns() + CONNECT_SIGNAL_RACE_TIMEOUT * NSEC_PER_SEC; + do { + c = xsocket(AF_VSOCK, SOCK_SEQPACKET, 0); + if (c < 0) + break; + + if (connect(c, (struct sockaddr *)&addr, alen) && errno == EINTR) + (void)connect(c, (struct sockaddr *)&bad_addr, alen); + + xclose(c); + p = accept(s, NULL, NULL); + if (p >= 0) + xclose(p); + } while (get_time_ns() < tout); + + ASSERT_OK(pthread_cancel(thread), "pthread_cancel"); + xpthread_join(thread, NULL); +close: + xclose(s); +restore: + ASSERT_NEQ(signal(SIGUSR1, orig_handler), SIG_ERR, "handler restore"); +} + void test_sockmap_basic(void) { if (test__start_subtest("sockmap create_update_free")) @@ -1108,4 +1203,6 @@ void test_sockmap_basic(void) test_sockmap_skb_verdict_vsock_poll(); if (test__start_subtest("sockmap vsock unconnected")) test_sockmap_vsock_unconnected(); + if (test__start_subtest("sockmap vsock connect signal race")) + test_sockmap_vsock_connect_signal_race(); } From patchwork Sun Mar 16 22:45:08 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michal Luczaj X-Patchwork-Id: 14018542 Received: from mailtransmit04.runbox.com (mailtransmit04.runbox.com [185.226.149.37]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8E77B1A0BDB; Sun, 16 Mar 2025 22:46:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.226.149.37 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742165176; cv=none; b=TGrgRM2gJK5GtdY2ms4OnlTq09zIUdHRCySD0iSgCXKg24KlcWu8owcl62PJDJ0FltxZeCjoDT8kE1OURO5NqAbuMp8RP0Bx6OUzVTKZZlg11cVitJ8wlvhMTP22tHdxUcu8t6Q45k4vLlxrpEwrAgbBLpLvuarFdaRYnKsYrF4= ARC-Message-Signature: i=1; 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Sun, 16 Mar 2025 23:46:07 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=rbox.co; s=selector1; h=Cc:To:In-Reply-To:References:Message-Id: Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date:From; bh=Qx6Q42lUm6Tq+A/H1tasLuFXsBAYaSnDK2lri+KURPw=; b=R2VSz5G1geS1IlY9yhGry/JtS+ jcIBvCOu0tq8IgLofQRHs/DLjNAneUf/Q/K9l0lBEpKvniVT8OPxLbZZb8xQieGrQvVohG+4J1jnU 5qkvnKZ80va+ERUtZjt8tdCtnhsrsC4kMQWPC8NIjnzjhZpYZe96gRUbSViEbjrD0gqZrI+1ydSsm SgyuS711t1C0s7vL0qifdIzNAE1ihEQi0s111p3j0oiartg7K/VLMbWYsBpco+bFArKFyEwGM0R7f C9kPv8eYHXfVLKnHcEfU8ehbKO3X61bShgw9CWx+zOg0P7dlVYQtTyWzWoTpNlZCK1w0w/MrFT+lh HkI6NlFA==; Received: from [10.9.9.74] (helo=submission03.runbox) by mailtransmit02.runbox with esmtp (Exim 4.86_2) (envelope-from ) id 1ttwkB-0007hM-Ap; Sun, 16 Mar 2025 23:46:07 +0100 Received: by submission03.runbox with esmtpsa [Authenticated ID (604044)] (TLS1.2:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.93) id 1ttwjr-00AYw2-L6; Sun, 16 Mar 2025 23:45:47 +0100 From: Michal Luczaj Date: Sun, 16 Mar 2025 23:45:08 +0100 Subject: [PATCH net v3 3/3] vsock/bpf: Fix bpf recvmsg() racing transport reassignment Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250316-vsock-trans-signal-race-v3-3-17a6862277c9@rbox.co> References: <20250316-vsock-trans-signal-race-v3-0-17a6862277c9@rbox.co> In-Reply-To: <20250316-vsock-trans-signal-race-v3-0-17a6862277c9@rbox.co> To: Stefano Garzarella , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , "Michael S. Tsirkin" , Bobby Eshleman , Andrii Nakryiko , Eduard Zingerman , Mykola Lysenko , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shuah Khan Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Michal Luczaj X-Mailer: b4 0.14.2 Signal delivery during connect() may lead to a disconnect of an already established socket. That involves removing socket from any sockmap and resetting state to SS_UNCONNECTED. While it correctly restores socket's proto, a call to vsock_bpf_recvmsg() might have been already under way in another thread. If the connect()ing thread reassigns the vsock transport to NULL, the recvmsg()ing thread may trigger a WARN_ON_ONCE. connect / state = SS_CONNECTED / sock_map_update_elem vsock_bpf_recvmsg psock = sk_psock_get() lock sk if signal_pending unhash sock_map_remove_links state = SS_UNCONNECTED release sk connect transport = NULL lock sk WARN_ON_ONCE(!vsk->transport) Protect recvmsg() from racing against transport reassignment. Enforce the sockmap invariant that psock implies transport: lock socket before getting psock. WARNING: CPU: 9 PID: 1222 at net/vmw_vsock/vsock_bpf.c:92 vsock_bpf_recvmsg+0xb55/0xe00 CPU: 9 UID: 0 PID: 1222 Comm: a.out Not tainted 6.14.0-rc5+ RIP: 0010:vsock_bpf_recvmsg+0xb55/0xe00 sock_recvmsg+0x1b2/0x220 __sys_recvfrom+0x190/0x270 __x64_sys_recvfrom+0xdc/0x1b0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Fixes: 634f1a7110b4 ("vsock: support sockmap") Signed-off-by: Michal Luczaj --- net/vmw_vsock/vsock_bpf.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) diff --git a/net/vmw_vsock/vsock_bpf.c b/net/vmw_vsock/vsock_bpf.c index c68fdaf09046b68254dac3ea70ffbe73dfa45cef..5138195d91fb258d4bc09b48e80e13651d62863a 100644 --- a/net/vmw_vsock/vsock_bpf.c +++ b/net/vmw_vsock/vsock_bpf.c @@ -73,28 +73,35 @@ static int __vsock_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int return err; } -static int vsock_bpf_recvmsg(struct sock *sk, struct msghdr *msg, - size_t len, int flags, int *addr_len) +static int vsock_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, + int flags, int *addr_len) { struct sk_psock *psock; struct vsock_sock *vsk; int copied; + /* Since signal delivery during connect() may reset the state of socket + * that's already in a sockmap, take the lock before checking on psock. + * This serializes a possible transport reassignment, protecting this + * function from running with NULL transport. + */ + lock_sock(sk); + psock = sk_psock_get(sk); - if (unlikely(!psock)) + if (unlikely(!psock)) { + release_sock(sk); return __vsock_recvmsg(sk, msg, len, flags); + } - lock_sock(sk); vsk = vsock_sk(sk); - if (WARN_ON_ONCE(!vsk->transport)) { copied = -ENODEV; goto out; } if (vsock_has_data(sk, psock) && sk_psock_queue_empty(psock)) { - release_sock(sk); sk_psock_put(sk, psock); + release_sock(sk); return __vsock_recvmsg(sk, msg, len, flags); } @@ -108,8 +115,8 @@ static int vsock_bpf_recvmsg(struct sock *sk, struct msghdr *msg, } if (sk_psock_queue_empty(psock)) { - release_sock(sk); sk_psock_put(sk, psock); + release_sock(sk); return __vsock_recvmsg(sk, msg, len, flags); } @@ -117,8 +124,8 @@ static int vsock_bpf_recvmsg(struct sock *sk, struct msghdr *msg, } out: - release_sock(sk); sk_psock_put(sk, psock); + release_sock(sk); return copied; }