2a6a870e44
This is a partial revert of the blamed commit, with a relevant change: mptcp_subflow_queue_clean() now just change the msk socket status and stop the worker, so that the UaF issue addressed by the blamed commit is not re-introduced. The above prevents the mptcp worker from running concurrently with inet_csk_listen_stop(), as such race would trigger a warning, as reported by Christoph: RSP: 002b:00007f784fe09cd8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e WARNING: CPU: 0 PID: 25807 at net/ipv4/inet_connection_sock.c:1387 inet_csk_listen_stop+0x664/0x870 net/ipv4/inet_connection_sock.c:1387 RAX: ffffffffffffffda RBX: 00000000006bc050 RCX: 00007f7850afd6a9 RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000004 Modules linked in: RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006bc05c R13: fffffffffffffea8 R14: 00000000006bc050 R15: 000000000001fe40 </TASK> CPU: 0 PID: 25807 Comm: syz-executor.7 Not tainted 6.2.0-g778e54711659 #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 RIP: 0010:inet_csk_listen_stop+0x664/0x870 net/ipv4/inet_connection_sock.c:1387 RAX: 0000000000000000 RBX: ffff888100dfbd40 RCX: 0000000000000000 RDX: ffff8881363aab80 RSI: ffffffff81c494f4 RDI: 0000000000000005 RBP: ffff888126dad080 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff888100dfe040 R13: 0000000000000001 R14: 0000000000000000 R15: ffff888100dfbdd8 FS: 00007f7850a2c800(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32d26000 CR3: 000000012fdd8006 CR4: 0000000000770ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> __tcp_close+0x5b2/0x620 net/ipv4/tcp.c:2875 __mptcp_close_ssk+0x145/0x3d0 net/mptcp/protocol.c:2427 mptcp_destroy_common+0x8a/0x1c0 net/mptcp/protocol.c:3277 mptcp_destroy+0x41/0x60 net/mptcp/protocol.c:3304 __mptcp_destroy_sock+0x56/0x140 net/mptcp/protocol.c:2965 __mptcp_close+0x38f/0x4a0 net/mptcp/protocol.c:3057 mptcp_close+0x24/0xe0 net/mptcp/protocol.c:3072 inet_release+0x53/0xa0 net/ipv4/af_inet.c:429 __sock_release+0x4e/0xf0 net/socket.c:651 sock_close+0x15/0x20 net/socket.c:1393 __fput+0xff/0x420 fs/file_table.c:321 task_work_run+0x8b/0xe0 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x113/0x120 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:296 do_syscall_64+0x46/0x90 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x72/0xdc RIP: 0033:0x7f7850af70dc RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007f7850af70dc RDX: 00007f7850a2c800 RSI: 0000000000000002 RDI: 0000000000000003 RBP: 00000000006bd980 R08: 0000000000000000 R09: 00000000000018a0 R10: 00000000316338a4 R11: 0000000000000293 R12: 0000000000211e31 R13: 00000000006bc05c R14: 00007f785062c000 R15: 0000000000211af0 Fixes: 0a3f4f1f9c27 ("mptcp: fix UaF in listener shutdown") Cc: stable@vger.kernel.org Reported-by: Christoph Paasch <cpaasch@apple.com> Link: https://github.com/multipath-tcp/mptcp_net-next/issues/371 Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.