diff --git a/.topmsg b/.topmsg index a9770f1a01c01..143e136ef328f 100644 --- a/.topmsg +++ b/.topmsg @@ -1,4 +1,59 @@ -From: Matthieu Baerts -Subject: [PATCH] t/mptcp-Only-send-extra-TCP-acks-in-eligible-socket-states +From: Mat Martineau +Subject: [PATCH] mptcp: Only send extra TCP acks in eligible socket states -Signed-off-by: Matthieu Baerts +Recent changes exposed a bug where specifically-timed requests to the +path manager netlink API could trigger a divide-by-zero in +__tcp_select_window(), as syzkaller does: + +divide error: 0000 [#1] SMP KASAN NOPTI +CPU: 0 PID: 9667 Comm: syz-executor.0 Not tainted 5.14.0-rc6+ #3 +Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 +RIP: 0010:__tcp_select_window+0x509/0xa60 net/ipv4/tcp_output.c:3016 +Code: 44 89 ff e8 c9 29 e9 fd 45 39 e7 0f 8d 20 ff ff ff e8 db 28 e9 fd 44 89 e3 e9 13 ff ff ff e8 ce 28 e9 fd 44 89 e0 44 89 e3 99 7c 24 04 29 d3 e9 fc fe ff ff e8 b7 28 e9 fd 44 89 f1 48 89 ea +RSP: 0018:ffff888031ccf020 EFLAGS: 00010216 +RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000040000 +RDX: 0000000000000000 RSI: ffff88811532c080 RDI: 0000000000000002 +RBP: 0000000000000000 R08: ffffffff835807c2 R09: 0000000000000000 +R10: 0000000000000004 R11: ffffed1020b92441 R12: 0000000000000000 +R13: 1ffff11006399e08 R14: 0000000000000000 R15: 0000000000000000 +FS: 00007fa4c8344700(0000) GS:ffff88811ae00000(0000) knlGS:0000000000000000 +CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 +CR2: 0000001b2f424000 CR3: 000000003e4e2003 CR4: 0000000000770ef0 +PKRU: 55555554 +Call Trace: + tcp_select_window net/ipv4/tcp_output.c:264 [inline] + __tcp_transmit_skb+0xc00/0x37a0 net/ipv4/tcp_output.c:1351 + __tcp_send_ack.part.0+0x3ec/0x760 net/ipv4/tcp_output.c:3972 + __tcp_send_ack net/ipv4/tcp_output.c:3978 [inline] + tcp_send_ack+0x7d/0xa0 net/ipv4/tcp_output.c:3978 + mptcp_pm_nl_addr_send_ack+0x1ab/0x380 net/mptcp/pm_netlink.c:654 + mptcp_pm_remove_addr+0x161/0x200 net/mptcp/pm.c:58 + mptcp_nl_remove_id_zero_address+0x197/0x460 net/mptcp/pm_netlink.c:1328 + mptcp_nl_cmd_del_addr+0x98b/0xd40 net/mptcp/pm_netlink.c:1359 + genl_family_rcv_msg_doit.isra.0+0x225/0x340 net/netlink/genetlink.c:731 + genl_family_rcv_msg net/netlink/genetlink.c:775 [inline] + genl_rcv_msg+0x341/0x5b0 net/netlink/genetlink.c:792 + netlink_rcv_skb+0x148/0x430 net/netlink/af_netlink.c:2504 + genl_rcv+0x24/0x40 net/netlink/genetlink.c:803 + netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] + netlink_unicast+0x537/0x750 net/netlink/af_netlink.c:1340 + netlink_sendmsg+0x846/0xd80 net/netlink/af_netlink.c:1929 + sock_sendmsg_nosec net/socket.c:704 [inline] + sock_sendmsg+0x14e/0x190 net/socket.c:724 + ____sys_sendmsg+0x709/0x870 net/socket.c:2403 + ___sys_sendmsg+0xff/0x170 net/socket.c:2457 + __sys_sendmsg+0xe5/0x1b0 net/socket.c:2486 + do_syscall_x64 arch/x86/entry/common.c:50 [inline] + do_syscall_64+0x38/0x90 arch/x86/entry/common.c:80 + entry_SYSCALL_64_after_hwframe+0x44/0xae + +mptcp_pm_nl_addr_send_ack() was attempting to send a TCP ACK on the +first subflow in the MPTCP socket's connection list without validating +that the subflow was in a suitable connection state. To address this, +always validate subflow state when sending extra ACKs on subflows +for address advertisement or subflow priority change. + +Fixes: 84dfe3677a6f ("mptcp: send out dedicated ADD_ADDR packet") +Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/229 +Co-developed-by: Paolo Abeni +Signed-off-by: Mat Martineau