From nobody Thu Nov 21 20:54:59 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D8BF81D1727; Mon, 21 Oct 2024 09:51:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729504300; cv=none; b=rAzmiwzpC0uU2qwpOnuEFPWRn9rVxpUDCZcXiCVLyYfnRfAZ+IZFOreuUgFLluBsnE2KQmqAp6ccq0+77q/0hryUOmzxnp1xNYCzoMjaksEgfvyP7qGMwqI5rsdDAtl4KZtRqvIoIL2aU1kiYluNZN00xioQQxfmmJCFGFZKo8I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729504300; c=relaxed/simple; bh=WnNwXPweW23M4D0vb8xLjSMbpz9iRjUXOttDt2ycC/Q=; h=Subject:To:Cc:From:Date:In-Reply-To:Message-ID:MIME-Version: Content-Type; b=XF3w00EjnuooXCvjQQJYSwP0Km3nrQHVzEr+j8cSs0NE5bObAb1cb8Obl8w57nPD920Lni4/Qyg5dmvdLIJB3PMCjD59GicZKSEMdjoaN19kPi0ii0+Xv5bGdatk88A26Hw8XUynACglWn+mwI56kyNA3JIUlTALNupIXu5mi20= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=rA48uUU4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="rA48uUU4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58AC8C4CEC3; Mon, 21 Oct 2024 09:51:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1729504299; bh=WnNwXPweW23M4D0vb8xLjSMbpz9iRjUXOttDt2ycC/Q=; h=Subject:To:Cc:From:Date:In-Reply-To:From; b=rA48uUU4NtgsMgtFmWnU2Cpeq6v1jIcmupkpJ/yWttzONmsco1XoC4fpq1amf53Gi UAV2gtw5liNWsW8r4aDumLIpFGlOzaC78LYL3rhPPLPNsXJ0m0CS0pYx/ETxiboG5z iEp9Zj7NpJFgZ5F5uE0hagvz0Sb9vvvv2vMaUEUM= Subject: Patch "mptcp: prevent MPC handshake on port-based signal endpoints" has been added to the 6.1-stable tree To: cong.wang@bytedance.com,gregkh@linuxfoundation.org,kuba@kernel.org,martineau@kernel.org,matttbe@kernel.org,mptcp@lists.linux.dev,pabeni@redhat.com,sashal@kernel.org,syzbot+f4aacdfef2c6a6529c3e@syzkaller.appspotmail.com Cc: From: Date: Mon, 21 Oct 2024 11:51:09 +0200 In-Reply-To: <20241018173656.2813913-6-matttbe@kernel.org> Message-ID: <2024102109-unwieldy-helper-d1b9@gregkh> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-stable: commit X-Patchwork-Hint: ignore Content-Type: text/plain; charset="utf-8" This is a note to let you know that I've just added the patch titled mptcp: prevent MPC handshake on port-based signal endpoints to the 6.1-stable tree which can be found at: http://www.kernel.org/git/?p=3Dlinux/kernel/git/stable/stable-queue.git= ;a=3Dsummary The filename of the patch is: mptcp-prevent-mpc-handshake-on-port-based-signal-endpoints.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. From stable+bounces-86874-greg=3Dkroah.com@vger.kernel.org Fri Oct 18 19:37= :15 2024 From: "Matthieu Baerts (NGI0)" Date: Fri, 18 Oct 2024 19:36:59 +0200 Subject: mptcp: prevent MPC handshake on port-based signal endpoints To: mptcp@lists.linux.dev, stable@vger.kernel.org, gregkh@linuxfoundation.o= rg Cc: Paolo Abeni , sashal@kernel.org, syzbot+f4aacdfef2c6= a6529c3e@syzkaller.appspotmail.com, Cong Wang , Ma= tthieu Baerts , Mat Martineau , J= akub Kicinski Message-ID: <20241018173656.2813913-6-matttbe@kernel.org> From: Paolo Abeni commit 3d041393ea8c815f773020fb4a995331a69c0139 upstream. Syzkaller reported a lockdep splat: =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D WARNING: possible recursive locking detected 6.11.0-rc6-syzkaller-00019-g67784a74e258 #0 Not tainted -------------------------------------------- syz-executor364/5113 is trying to acquire lock: ffff8880449f1958 (k-slock-AF_INET){+.-.}-{2:2}, at: spin_lock include/lin= ux/spinlock.h:351 [inline] ffff8880449f1958 (k-slock-AF_INET){+.-.}-{2:2}, at: sk_clone_lock+0x2cd/0= xf40 net/core/sock.c:2328 but task is already holding lock: ffff88803fe3cb58 (k-slock-AF_INET){+.-.}-{2:2}, at: spin_lock include/lin= ux/spinlock.h:351 [inline] ffff88803fe3cb58 (k-slock-AF_INET){+.-.}-{2:2}, at: sk_clone_lock+0x2cd/0= xf40 net/core/sock.c:2328 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(k-slock-AF_INET); lock(k-slock-AF_INET); *** DEADLOCK *** May be due to missing lock nesting notation 7 locks held by syz-executor364/5113: #0: ffff8880449f0e18 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock includ= e/net/sock.h:1607 [inline] #0: ffff8880449f0e18 (sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_sendmsg+0x= 153/0x1b10 net/mptcp/protocol.c:1806 #1: ffff88803fe39ad8 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock incl= ude/net/sock.h:1607 [inline] #1: ffff88803fe39ad8 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_sendmsg_= fastopen+0x11f/0x530 net/mptcp/protocol.c:1727 #2: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire i= nclude/linux/rcupdate.h:326 [inline] #2: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock incl= ude/linux/rcupdate.h:838 [inline] #2: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: __ip_queue_xmit+0x= 5f/0x1b80 net/ipv4/ip_output.c:470 #3: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire i= nclude/linux/rcupdate.h:326 [inline] #3: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock incl= ude/linux/rcupdate.h:838 [inline] #3: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+= 0x45f/0x1390 net/ipv4/ip_output.c:228 #4: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: local_lock_acquire= include/linux/local_lock_internal.h:29 [inline] #4: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: process_backlog+0x= 33b/0x15b0 net/core/dev.c:6104 #5: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire i= nclude/linux/rcupdate.h:326 [inline] #5: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock incl= ude/linux/rcupdate.h:838 [inline] #5: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: ip_local_deliver_f= inish+0x230/0x5f0 net/ipv4/ip_input.c:232 #6: ffff88803fe3cb58 (k-slock-AF_INET){+.-.}-{2:2}, at: spin_lock includ= e/linux/spinlock.h:351 [inline] #6: ffff88803fe3cb58 (k-slock-AF_INET){+.-.}-{2:2}, at: sk_clone_lock+0x= 2cd/0xf40 net/core/sock.c:2328 stack backtrace: CPU: 0 UID: 0 PID: 5113 Comm: syz-executor364 Not tainted 6.11.0-rc6-syzk= aller-00019-g67784a74e258 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.= 16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 check_deadlock kernel/locking/lockdep.c:3061 [inline] validate_chain+0x15d3/0x5900 kernel/locking/lockdep.c:3855 __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] sk_clone_lock+0x2cd/0xf40 net/core/sock.c:2328 mptcp_sk_clone_init+0x32/0x13c0 net/mptcp/protocol.c:3279 subflow_syn_recv_sock+0x931/0x1920 net/mptcp/subflow.c:874 tcp_check_req+0xfe4/0x1a20 net/ipv4/tcp_minisocks.c:853 tcp_v4_rcv+0x1c3e/0x37f0 net/ipv4/tcp_ipv4.c:2267 ip_protocol_deliver_rcu+0x22e/0x440 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x341/0x5f0 net/ipv4/ip_input.c:233 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5661 [inline] __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5775 process_backlog+0x662/0x15b0 net/core/dev.c:6108 __napi_poll+0xcb/0x490 net/core/dev.c:6772 napi_poll net/core/dev.c:6841 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:6963 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554 do_softirq+0x11b/0x1e0 kernel/softirq.c:455 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:908 [inline] __dev_queue_xmit+0x1763/0x3e90 net/core/dev.c:4450 dev_queue_xmit include/linux/netdevice.h:3105 [inline] neigh_hh_output include/net/neighbour.h:526 [inline] neigh_output include/net/neighbour.h:540 [inline] ip_finish_output2+0xd41/0x1390 net/ipv4/ip_output.c:235 ip_local_out net/ipv4/ip_output.c:129 [inline] __ip_queue_xmit+0x118c/0x1b80 net/ipv4/ip_output.c:535 __tcp_transmit_skb+0x2544/0x3b30 net/ipv4/tcp_output.c:1466 tcp_rcv_synsent_state_process net/ipv4/tcp_input.c:6542 [inline] tcp_rcv_state_process+0x2c32/0x4570 net/ipv4/tcp_input.c:6729 tcp_v4_do_rcv+0x77d/0xc70 net/ipv4/tcp_ipv4.c:1934 sk_backlog_rcv include/net/sock.h:1111 [inline] __release_sock+0x214/0x350 net/core/sock.c:3004 release_sock+0x61/0x1f0 net/core/sock.c:3558 mptcp_sendmsg_fastopen+0x1ad/0x530 net/mptcp/protocol.c:1733 mptcp_sendmsg+0x1884/0x1b10 net/mptcp/protocol.c:1812 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597 ___sys_sendmsg net/socket.c:2651 [inline] __sys_sendmmsg+0x3b2/0x740 net/socket.c:2737 __do_sys_sendmmsg net/socket.c:2766 [inline] __se_sys_sendmmsg net/socket.c:2763 [inline] __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2763 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f04fb13a6b9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 01 1a 00 00 90 48 89 f8 48 89 f= 7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff= ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd651f42d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f04fb13a6b9 RDX: 0000000000000001 RSI: 0000000020000d00 RDI: 0000000000000004 RBP: 00007ffd651f4310 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000020000080 R11: 0000000000000246 R12: 00000000000f4240 R13: 00007f04fb187449 R14: 00007ffd651f42f4 R15: 00007ffd651f4300 As noted by Cong Wang, the splat is false positive, but the code path leading to the report is an unexpected one: a client is attempting an MPC handshake towards the in-kernel listener created by the in-kernel PM for a port based signal endpoint. Such connection will be never accepted; many of them can make the listener queue full and preventing the creation of MPJ subflow via such listener - its intended role. Explicitly detect this scenario at initial-syn time and drop the incoming MPC request. Fixes: 1729cf186d8a ("mptcp: create the listening socket for new port") Cc: stable@vger.kernel.org Reported-by: syzbot+f4aacdfef2c6a6529c3e@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3Df4aacdfef2c6a6529c3e Cc: Cong Wang Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20241014-net-mptcp-mpc-port-endp-v2-1-7faea8= e6b6ae@kernel.org Signed-off-by: Jakub Kicinski [ Conflicts in mib.[ch], because commit 6982826fe5e5 ("mptcp: fallback to TCP after SYN+MPC drops"), and commit 27069e7cb3d1 ("mptcp: disable active MPTCP in case of blackhole") are linked to new features, not available in this version. Resolving the conflicts is easy, simply adding the new lines declaring the new "endpoint attempt" MIB entry. Also a conflict in protocol.h, because commit fce68b03086f ("mptcp: add scheduled in mptcp_subflow_context") is not in this version, and changes the context by introducing 'scheduled' variable just before. Also a conflict in pm_netlink.c, because commit 3aa362494170 ("mptcp: avoid ssock usage in mptcp_pm_nl_create_listen_socket()") is not in this version, and refactor the function: that's fine, we can still set pm_listener before doing the 'listen()', taking 'ssock->sk' as 'ssk' is not defined before this refactoring. ] Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Greg Kroah-Hartman --- net/mptcp/mib.c | 1 + net/mptcp/mib.h | 1 + net/mptcp/pm_netlink.c | 1 + net/mptcp/protocol.h | 1 + net/mptcp/subflow.c | 11 +++++++++++ 5 files changed, 15 insertions(+) --- a/net/mptcp/mib.c +++ b/net/mptcp/mib.c @@ -15,6 +15,7 @@ static const struct snmp_mib mptcp_snmp_ SNMP_MIB_ITEM("MPCapableACKRX", MPTCP_MIB_MPCAPABLEPASSIVEACK), SNMP_MIB_ITEM("MPCapableFallbackACK", MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK), SNMP_MIB_ITEM("MPCapableFallbackSYNACK", MPTCP_MIB_MPCAPABLEACTIVEFALLBAC= K), + SNMP_MIB_ITEM("MPCapableEndpAttempt", MPTCP_MIB_MPCAPABLEENDPATTEMPT), SNMP_MIB_ITEM("MPFallbackTokenInit", MPTCP_MIB_TOKENFALLBACKINIT), SNMP_MIB_ITEM("MPTCPRetrans", MPTCP_MIB_RETRANSSEGS), SNMP_MIB_ITEM("MPJoinNoTokenFound", MPTCP_MIB_JOINNOTOKEN), --- a/net/mptcp/mib.h +++ b/net/mptcp/mib.h @@ -8,6 +8,7 @@ enum linux_mptcp_mib_field { MPTCP_MIB_MPCAPABLEPASSIVEACK, /* Received third ACK with MP_CAPABLE */ MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK,/* Server-side fallback during 3-way h= andshake */ MPTCP_MIB_MPCAPABLEACTIVEFALLBACK, /* Client-side fallback during 3-way h= andshake */ + MPTCP_MIB_MPCAPABLEENDPATTEMPT, /* Prohibited MPC to port-based endp */ MPTCP_MIB_TOKENFALLBACKINIT, /* Could not init/allocate token */ MPTCP_MIB_RETRANSSEGS, /* Segments retransmitted at the MPTCP-level */ MPTCP_MIB_JOINNOTOKEN, /* Received MP_JOIN but the token was not found */ --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -1111,6 +1111,7 @@ static int mptcp_pm_nl_create_listen_soc } =20 inet_sk_state_store(newsk, TCP_LISTEN); + WRITE_ONCE(mptcp_subflow_ctx(ssock->sk)->pm_listener, true); err =3D kernel_listen(ssock, backlog); if (err) { pr_warn("kernel_listen error, err=3D%d", err); --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -483,6 +483,7 @@ struct mptcp_subflow_context { close_event_done : 1, /* has done the post-closed part */ __unused : 9; enum mptcp_data_avail data_avail; + bool pm_listener; /* a listener managed by the kernel PM? */ u32 remote_nonce; u64 thmac; u32 local_nonce; --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -131,6 +131,13 @@ static void subflow_add_reset_reason(str } } =20 +static int subflow_reset_req_endp(struct request_sock *req, struct sk_buff= *skb) +{ + SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEENDPATTEMPT); + subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT); + return -EPERM; +} + /* Init mptcp request socket. * * Returns an error code if a JOIN has failed and a TCP reset @@ -162,6 +169,8 @@ static int subflow_check_req(struct requ if (opt_mp_capable) { SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEPASSIVE); =20 + if (unlikely(listener->pm_listener)) + return subflow_reset_req_endp(req, skb); if (opt_mp_join) return 0; } else if (opt_mp_join) { @@ -169,6 +178,8 @@ static int subflow_check_req(struct requ =20 if (mp_opt.backup) SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINSYNBACKUPRX); + } else if (unlikely(listener->pm_listener)) { + return subflow_reset_req_endp(req, skb); } =20 if (opt_mp_capable && listener->request_mptcp) { Patches currently in stable-queue which might be from matttbe@kernel.org are queue-6.1/tcp-fix-mptcp-dss-corruption-due-to-large-pmtu-xmit.patch queue-6.1/mptcp-pm-fix-uaf-read-in-mptcp_pm_nl_rm_addr_or_subflow.patch queue-6.1/mptcp-prevent-mpc-handshake-on-port-based-signal-endpoints.patch