From mboxrd@z Thu Jan 1 00:00:00 1970 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 F40851DEFD8; Sun, 9 Feb 2025 17:48:35 +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=1739123316; cv=none; b=jZR0A6BdBD7xvD0jErPEsCrBoOyygCZH8Hp3QUWnO0CQFzJDBHLr5hB5SyhEKpX+ubr5oJOJyc3pNxon/6yexf49rATf6yhfWSoLJAnfXkcKp85+UWe1SnSaeYPfzNr7oaJyOymIpwv0X+3Nqulu8vwefBqdJeEPVttrBdHHAbY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739123316; c=relaxed/simple; bh=o9RxgEAA8M3HdgmOXx6IvDJqMWwAsv0aqi2pUgRnNSI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GEMo3/y3WEr3ugwWfyO7K7+NifuAGOyrOPva9FZ+kKjaqN5Z75ag9mpj84GcYh/9oHWOb2gsddVcxO8s4nooHPa4qJkL+1Nv3CNYGF68b44wmkGq/6P01YUubxBoGc6zI7wOERwTLdcBDwimaK4JFOXcrq1qkAfB98nVh9p30so= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=S2/CGk0F; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="S2/CGk0F" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EAC75C4CEE7; Sun, 9 Feb 2025 17:48:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739123315; bh=o9RxgEAA8M3HdgmOXx6IvDJqMWwAsv0aqi2pUgRnNSI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S2/CGk0FzgitnR0iR/Dfzih4nxDHAlb0utSn70uBmz40qAjlO+heSbArydBKLGIpb P2+qLi/UtCmYUhoJqo1yvkP7cNV18nl1bB6IbAc+FaCrhHmFeXZ3J8zpIbAIYRX77+ vLt+KghX2vgVKf3++1FahSQfkk5WfbOntdhqVmA8kPN3ccb34TDk1CevxMTdJ1I+BM Z6cHJusgiRzmeKDLwJMjH+ToRtw747VTDjcd9/5G0TQ9evGB1mDdYAslDqGGFjRUG1 cte3aQMTodsxoS/Yx1gJq6j0+vqIfH1CVAbBiqorZn1zNxsi/N+1/4QyzhxK5W3zlE 5ci+jcEqpw2kw== From: "Matthieu Baerts (NGI0)" To: mptcp@lists.linux.dev, stable@vger.kernel.org, gregkh@linuxfoundation.org Cc: "Matthieu Baerts (NGI0)" , syzbot+cd16e79c1e45f3fe0377@syzkaller.appspotmail.com, Mat Martineau , Jakub Kicinski Subject: [PATCH 6.1.y 1/2] mptcp: pm: only set fullmesh for subflow endp Date: Sun, 9 Feb 2025 18:48:30 +0100 Message-ID: <20250209174828.3397229-5-matttbe@kernel.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <2025020435-eagle-precision-e8dd@gregkh> References: <2025020435-eagle-precision-e8dd@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5977; i=matttbe@kernel.org; h=from:subject; bh=o9RxgEAA8M3HdgmOXx6IvDJqMWwAsv0aqi2pUgRnNSI=; b=owEBbQKS/ZANAwAIAfa3gk9CaaBzAcsmYgBnqOpsj+tMH+aFr8SGu9bASQxHpuL5MUNWxJtOP Fw73obEGqSJAjMEAAEIAB0WIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZ6jqbAAKCRD2t4JPQmmg c/97EACScprBHhNai0b9polD6jcCHkDkZvjVgYRIhbhhPvgJWJd7NaxUxBxUC7I6aFy1ElkEewh 74oHmQXmmwrhUHF5BLAT720qE8DXG7F6W3Pa7iSqKSmWhnqmzYwcCKlDiZWBDfKrAKjyy2x8L6W sohbKVU0+zTYcLHkD4spftbeJP9YwaRyPwrKh/jqOv0ZXXLhT3PA/vKNrxyy1pzBTxxqpjQQ6qJ M4cpHoVBixlLAnEDGA09yThg6smuQ56OdYvULA5A74oqV9CvhqBXmksIkZGGMOhjPdQllBAWe1r aJwm6vy5pQa/l2vd7ImcVzLUoubbHTRvAnRsQ/InV3Zim9D3IHJ7sN1tw08XjwvnfCFDHovYMTw UK7H2ar4NuPwX7tk+dJESmm6yBXAdouM2GeltjgwBikqiUxrSwlwC+JhQsEsHgHaFPhsGs9Op5R Emx02+SA5vPAlLI8m+TM0Z8UqHObZKa9kWXiRIOFUeTuHr5rHaxSNMVlaO/Ls5JaFPp0Npg2s6E LbuMO3PQE0CgQEXnOPuv9vmHjta/uWbJXGM3pq9NLN1UzUfRpm2WFPw5T5bKEJZeIjj5UrsqNCw DuXFaJWo2OtA1rACPz+q2foGClojJkpc4t/JjD2SAOEb935wqmX0sll57dsafW0wK0qiIqbQnV1 Ij9M3u7keO+oQUA== X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 Content-Transfer-Encoding: 8bit commit 1bb0d1348546ad059f55c93def34e67cb2a034a6 upstream. With the in-kernel path-manager, it is possible to change the 'fullmesh' flag. The code in mptcp_pm_nl_fullmesh() expects to change it only on 'subflow' endpoints, to recreate more or less subflows using the linked address. Unfortunately, the set_flags() hook was a bit more permissive, and allowed 'implicit' endpoints to get the 'fullmesh' flag while it is not allowed before. That's what syzbot found, triggering the following warning: WARNING: CPU: 0 PID: 6499 at net/mptcp/pm_netlink.c:1496 __mark_subflow_endp_available net/mptcp/pm_netlink.c:1496 [inline] WARNING: CPU: 0 PID: 6499 at net/mptcp/pm_netlink.c:1496 mptcp_pm_nl_fullmesh net/mptcp/pm_netlink.c:1980 [inline] WARNING: CPU: 0 PID: 6499 at net/mptcp/pm_netlink.c:1496 mptcp_nl_set_flags net/mptcp/pm_netlink.c:2003 [inline] WARNING: CPU: 0 PID: 6499 at net/mptcp/pm_netlink.c:1496 mptcp_pm_nl_set_flags+0x974/0xdc0 net/mptcp/pm_netlink.c:2064 Modules linked in: CPU: 0 UID: 0 PID: 6499 Comm: syz.1.413 Not tainted 6.13.0-rc5-syzkaller-00172-gd1bf27c4e176 #0 Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:__mark_subflow_endp_available net/mptcp/pm_netlink.c:1496 [inline] RIP: 0010:mptcp_pm_nl_fullmesh net/mptcp/pm_netlink.c:1980 [inline] RIP: 0010:mptcp_nl_set_flags net/mptcp/pm_netlink.c:2003 [inline] RIP: 0010:mptcp_pm_nl_set_flags+0x974/0xdc0 net/mptcp/pm_netlink.c:2064 Code: 01 00 00 49 89 c5 e8 fb 45 e8 f5 e9 b8 fc ff ff e8 f1 45 e8 f5 4c 89 f7 be 03 00 00 00 e8 44 1d 0b f9 eb a0 e8 dd 45 e8 f5 90 <0f> 0b 90 e9 17 ff ff ff 89 d9 80 e1 07 38 c1 0f 8c c9 fc ff ff 48 RSP: 0018:ffffc9000d307240 EFLAGS: 00010293 RAX: ffffffff8bb72e03 RBX: 0000000000000000 RCX: ffff88807da88000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000d307430 R08: ffffffff8bb72cf0 R09: 1ffff1100b842a5e R10: dffffc0000000000 R11: ffffed100b842a5f R12: ffff88801e2e5ac0 R13: ffff88805c214800 R14: ffff88805c2152e8 R15: 1ffff1100b842a5d FS: 00005555619f6500(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020002840 CR3: 00000000247e6000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0xb14/0xec0 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2542 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline] netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1347 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1891 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:726 ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2583 ___sys_sendmsg net/socket.c:2637 [inline] __sys_sendmsg+0x269/0x350 net/socket.c:2669 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: 0033:0x7f5fe8785d29 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff571f5558 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f5fe8975fa0 RCX: 00007f5fe8785d29 RDX: 0000000000000000 RSI: 0000000020000480 RDI: 0000000000000007 RBP: 00007f5fe8801b08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5fe8975fa0 R14: 00007f5fe8975fa0 R15: 00000000000011f4 Here, syzbot managed to set the 'fullmesh' flag on an 'implicit' and used -- according to 'id_avail_bitmap' -- endpoint, causing the PM to try decrement the local_addr_used counter which is only incremented for the 'subflow' endpoint. Note that 'no type' endpoints -- not 'subflow', 'signal', 'implicit' -- are fine, because their ID will not be marked as used in the 'id_avail' bitmap, and setting 'fullmesh' can help forcing the creation of subflow when receiving an ADD_ADDR. Fixes: 73c762c1f07d ("mptcp: set fullmesh flag in pm_netlink") Cc: stable@vger.kernel.org Reported-by: syzbot+cd16e79c1e45f3fe0377@syzkaller.appspotmail.com Closes: https://lore.kernel.org/6786ac51.050a0220.216c54.00a6.GAE@google.com Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/540 Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250123-net-mptcp-syzbot-issues-v1-2-af73258a726f@kernel.org Signed-off-by: Jakub Kicinski [ Conflicts in pm_netlink.c, because the code has been moved around in commit 6a42477fe449 ("mptcp: update set_flags interfaces"), but the same fix can still be applied at the original place. ] Signed-off-by: Matthieu Baerts (NGI0) --- net/mptcp/pm_netlink.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 3fd7de56a30f..ddbc352f8420 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -2086,7 +2086,8 @@ static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info) return -EINVAL; } if ((addr.flags & MPTCP_PM_ADDR_FLAG_FULLMESH) && - (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) { + (entry->flags & (MPTCP_PM_ADDR_FLAG_SIGNAL | + MPTCP_PM_ADDR_FLAG_IMPLICIT))) { spin_unlock_bh(&pernet->lock); return -EINVAL; } -- 2.47.1