linux-toradex.git/drivers/connector/cn_proc.c, branch v6.7 Linux kernel for Apalis and Colibri modules connector: Fix proc_event_num_listeners count not cleared 2024-01-02T14:13:48+00:00 wangkeqi wangkeqiwang@didiglobal.com 2023-12-23T06:50:32+00:00 c46bfba1337d301661dbb23cfd905d4cb51f27ca When we register a cn_proc listening event, the proc_event_num_listener variable will be incremented by one, but if PROC_CN_MCAST_IGNORE is not called, the count will not decrease. This will cause the proc_*_connector function to take the wrong path. It will reappear when the forkstat tool exits via ctrl + c. We solve this problem by determining whether there are still listeners to clear proc_event_num_listener. Signed-off-by: wangkeqi <wangkeqiwang@didiglobal.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
When we register a cn_proc listening event, the proc_event_num_listener
variable will be incremented by one, but if PROC_CN_MCAST_IGNORE is
not called, the count will not decrease.
This will cause the proc_*_connector function to take the wrong path.
It will reappear when the forkstat tool exits via ctrl + c.
We solve this problem by determining whether
there are still listeners to clear proc_event_num_listener.

Signed-off-by: wangkeqi <wangkeqiwang@didiglobal.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix NULL pointer dereference in cn_filter() 2023-10-24T08:53:45+00:00 Anjali Kulkarni anjali.k.kulkarni@oracle.com 2023-10-20T23:40:58+00:00 9644bc49705723bf7c69aa9bf542bb5161b91dba Check that sk_user_data is not NULL, else return from cn_filter(). Could not reproduce this issue, but Oliver Sang verified it has fixed the "Closes" problem below. Fixes: 2aa1f7a1f47c ("connector/cn_proc: Add filtering to fix some bugs") Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202309201456.84c19e27-oliver.sang@intel.com/ Signed-off-by: Anjali Kulkarni <anjali.k.kulkarni@oracle.com> Link: https://lore.kernel.org/r/20231020234058.2232347-1-anjali.k.kulkarni@oracle.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> 
Check that sk_user_data is not NULL, else return from cn_filter().
Could not reproduce this issue, but Oliver Sang verified it has fixed
the "Closes" problem below.

Fixes: 2aa1f7a1f47c ("connector/cn_proc: Add filtering to fix some bugs")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202309201456.84c19e27-oliver.sang@intel.com/
Signed-off-by: Anjali Kulkarni <anjali.k.kulkarni@oracle.com>
Link: https://lore.kernel.org/r/20231020234058.2232347-1-anjali.k.kulkarni@oracle.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
connector/cn_proc: Allow non-root users access 2023-07-23T10:34:22+00:00 Anjali Kulkarni anjali.k.kulkarni@oracle.com 2023-07-19T20:18:20+00:00 bfdfdc2f3b7073571ce40b6d19193002b0126b6a There were a couple of reasons for not allowing non-root users access initially - one is there was some point no proper receive buffer management in place for netlink multicast. But that should be long fixed. See link below for more context. Second is that some of the messages may contain data that is root only. But this should be handled with a finer granularity, which is being done at the protocol layer. The only problematic protocols are nf_queue and the firewall netlink. Hence, this restriction for non-root access was relaxed for NETLINK_ROUTE initially: https://lore.kernel.org/all/20020612013101.A22399@wotan.suse.de/ This restriction has also been removed for following protocols: NETLINK_KOBJECT_UEVENT, NETLINK_AUDIT, NETLINK_SOCK_DIAG, NETLINK_GENERIC, NETLINK_SELINUX. Since process connector messages are not sensitive (process fork, exit notifications etc.), and anyone can read /proc data, we can allow non-root access here. However, since process event notification is not the only consumer of NETLINK_CONNECTOR, we can make this change even more fine grained than the protocol level, by checking for multicast group within the protocol. Allow non-root access for NETLINK_CONNECTOR via NL_CFG_F_NONROOT_RECV but add new bind function cn_bind(), which allows non-root access only for CN_IDX_PROC multicast group. Signed-off-by: Anjali Kulkarni <anjali.k.kulkarni@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
There were a couple of reasons for not allowing non-root users access
initially  - one is there was some point no proper receive buffer
management in place for netlink multicast. But that should be long
fixed. See link below for more context.

Second is that some of the messages may contain data that is root only. But
this should be handled with a finer granularity, which is being done at the
protocol layer.  The only problematic protocols are nf_queue and the
firewall netlink. Hence, this restriction for non-root access was relaxed
for NETLINK_ROUTE initially:
https://lore.kernel.org/all/20020612013101.A22399@wotan.suse.de/

This restriction has also been removed for following protocols:
NETLINK_KOBJECT_UEVENT, NETLINK_AUDIT, NETLINK_SOCK_DIAG,
NETLINK_GENERIC, NETLINK_SELINUX.

Since process connector messages are not sensitive (process fork, exit
notifications etc.), and anyone can read /proc data, we can allow non-root
access here. However, since process event notification is not the only
consumer of NETLINK_CONNECTOR, we can make this change even more
fine grained than the protocol level, by checking for multicast group
within the protocol.

Allow non-root access for NETLINK_CONNECTOR via NL_CFG_F_NONROOT_RECV
but add new bind function cn_bind(), which allows non-root access only
for CN_IDX_PROC multicast group.

Signed-off-by: Anjali Kulkarni <anjali.k.kulkarni@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
connector/cn_proc: Performance improvements 2023-07-23T10:34:22+00:00 Anjali Kulkarni anjali.k.kulkarni@oracle.com 2023-07-19T20:18:19+00:00 743acf351bae1ff7ff4aaadd6a406d4d6091d90b This patch adds the capability to filter messages sent by the proc connector on the event type supplied in the message from the client to the connector. The client can register to listen for an event type given in struct proc_input. This event based filteting will greatly enhance performance - handling 8K exits takes about 70ms, whereas 8K-forks + 8K-exits takes about 150ms & handling 8K-forks + 8K-exits + 8K-execs takes 200ms. There are currently 9 different types of events, and we need to listen to all of them. Also, measuring the time using pidfds for monitoring 8K process exits took much longer - 200ms, as compared to 70ms using only exit notifications of proc connector. We also add a new event type - PROC_EVENT_NONZERO_EXIT, which is only sent by kernel to a listening application when any process exiting, has a non-zero exit status. This will help the clients like Oracle DB, where a monitoring process wants notfications for non-zero process exits so it can cleanup after them. This kind of a new event could also be useful to other applications like Google's lmkd daemon, which needs a killed process's exit notification. The patch takes care that existing clients using old mechanism of not sending the event type work without any changes. cn_filter function checks to see if the event type being notified via proc connector matches the event type requested by client, before sending(matches) or dropping(does not match) a packet. Signed-off-by: Anjali Kulkarni <anjali.k.kulkarni@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
This patch adds the capability to filter messages sent by the proc
connector on the event type supplied in the message from the client
to the connector. The client can register to listen for an event type
given in struct proc_input.

This event based filteting will greatly enhance performance - handling
8K exits takes about 70ms, whereas 8K-forks + 8K-exits takes about 150ms
& handling 8K-forks + 8K-exits + 8K-execs takes 200ms. There are currently
9 different types of events, and we need to listen to all of them. Also,
measuring the time using pidfds for monitoring 8K process exits took
much longer - 200ms, as compared to 70ms using only exit notifications of
proc connector.

We also add a new event type - PROC_EVENT_NONZERO_EXIT, which is
only sent by kernel to a listening application when any process exiting,
has a non-zero exit status. This will help the clients like Oracle DB,
where a monitoring process wants notfications for non-zero process exits
so it can cleanup after them.

This kind of a new event could also be useful to other applications like
Google's lmkd daemon, which needs a killed process's exit notification.

The patch takes care that existing clients using old mechanism of not
sending the event type work without any changes.

cn_filter function checks to see if the event type being notified via
proc connector matches the event type requested by client, before
sending(matches) or dropping(does not match) a packet.

Signed-off-by: Anjali Kulkarni <anjali.k.kulkarni@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
connector/cn_proc: Add filtering to fix some bugs 2023-07-23T10:34:22+00:00 Anjali Kulkarni anjali.k.kulkarni@oracle.com 2023-07-19T20:18:18+00:00 2aa1f7a1f47ce8dac7593af605aaa859b3cf3bb1 The current proc connector code has the foll. bugs - if there are more than one listeners for the proc connector messages, and one of them deregisters for listening using PROC_CN_MCAST_IGNORE, they will still get all proc connector messages, as long as there is another listener. Another issue is if one client calls PROC_CN_MCAST_LISTEN, and another one calls PROC_CN_MCAST_IGNORE, then both will end up not getting any messages. This patch adds filtering and drops packet if client has sent PROC_CN_MCAST_IGNORE. This data is stored in the client socket's sk_user_data. In addition, we only increment or decrement proc_event_num_listeners once per client. This fixes the above issues. cn_release is the release function added for NETLINK_CONNECTOR. It uses the newly added netlink_release function added to netlink_sock. It will free sk_user_data. Signed-off-by: Anjali Kulkarni <anjali.k.kulkarni@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
The current proc connector code has the foll. bugs - if there are more
than one listeners for the proc connector messages, and one of them
deregisters for listening using PROC_CN_MCAST_IGNORE, they will still get
all proc connector messages, as long as there is another listener.

Another issue is if one client calls PROC_CN_MCAST_LISTEN, and another one
calls PROC_CN_MCAST_IGNORE, then both will end up not getting any messages.

This patch adds filtering and drops packet if client has sent
PROC_CN_MCAST_IGNORE. This data is stored in the client socket's
sk_user_data. In addition, we only increment or decrement
proc_event_num_listeners once per client. This fixes the above issues.

cn_release is the release function added for NETLINK_CONNECTOR. It uses
the newly added netlink_release function added to netlink_sock. It will
free sk_user_data.

Signed-off-by: Anjali Kulkarni <anjali.k.kulkarni@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
connector/cn_proc: Use task_is_in_init_pid_ns() 2022-01-27T02:57:09+00:00 Leo Yan leo.yan@linaro.org 2022-01-26T05:04:27+00:00 42c66d16756402c4749d94f005a998a43e8fa338 This patch replaces open code with task_is_in_init_pid_ns() to check if a task is in root PID namespace. Signed-off-by: Leo Yan <leo.yan@linaro.org> Acked-by: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
This patch replaces open code with task_is_in_init_pid_ns() to check if
a task is in root PID namespace.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
connector/cn_proc: Protect send_msg() with a local lock 2020-05-28T08:31:10+00:00 Mike Galbraith umgwanakikbuti@gmail.com 2020-05-27T20:11:17+00:00 3e92fd7bd2b8418b53cb7304855b8b69bedbe2b4 send_msg() disables preemption to avoid out-of-order messages. As the code inside the preempt disabled section acquires regular spinlocks, which are converted to 'sleeping' spinlocks on a PREEMPT_RT kernel and eventually calls into a memory allocator, this conflicts with the RT semantics. Convert it to a local_lock which allows RT kernels to substitute them with a real per CPU lock. On non RT kernels this maps to preempt_disable() as before. No functional change. [bigeasy: Patch description] Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20200527201119.1692513-6-bigeasy@linutronix.de 
send_msg() disables preemption to avoid out-of-order messages. As the
code inside the preempt disabled section acquires regular spinlocks,
which are converted to 'sleeping' spinlocks on a PREEMPT_RT kernel and
eventually calls into a memory allocator, this conflicts with the RT
semantics.

Convert it to a local_lock which allows RT kernels to substitute them with
a real per CPU lock. On non RT kernels this maps to preempt_disable() as
before. No functional change.

[bigeasy: Patch description]

Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20200527201119.1692513-6-bigeasy@linutronix.de
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30T18:26:35+00:00 Thomas Gleixner tglx@linutronix.de 2019-05-27T06:55:05+00:00 1a59d1b8e05ea6ab45f7e18897de1ef0e6bc3da6 Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details you
  should have received a copy of the gnu general public license along
  with this program if not write to the free software foundation inc
  59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
connector: fix unsafe usage of ->real_parent 2019-03-08T23:06:38+00:00 Li RongQing lirongqing@baidu.com 2019-03-06T06:46:27+00:00 6d2b0f02f5a07a4bf02e4cbc90d7eaa85cac2986 proc_exit_connector() uses ->real_parent lockless. This is not safe that its parent can go away at any moment, so use RCU to protect it, and ensure that this task is not released. [ 747.624551] ================================================================== [ 747.632946] BUG: KASAN: use-after-free in proc_exit_connector+0x1f7/0x310 [ 747.640686] Read of size 4 at addr ffff88a0276988e0 by task sshd/2882 [ 747.648032] [ 747.649804] CPU: 11 PID: 2882 Comm: sshd Tainted: G E 4.19.26-rc2 #11 [ 747.658629] Hardware name: IBM x3550M4 -[7914OFV]-/00AM544, BIOS -[D7E142BUS-1.71]- 07/31/2014 [ 747.668419] Call Trace: [ 747.671269] dump_stack+0xf0/0x19b [ 747.675186] ? show_regs_print_info+0x5/0x5 [ 747.679988] ? kmsg_dump_rewind_nolock+0x59/0x59 [ 747.685302] print_address_description+0x6a/0x270 [ 747.691162] kasan_report+0x258/0x380 [ 747.695835] ? proc_exit_connector+0x1f7/0x310 [ 747.701402] proc_exit_connector+0x1f7/0x310 [ 747.706767] ? proc_coredump_connector+0x2d0/0x2d0 [ 747.712715] ? _raw_write_unlock_irq+0x29/0x50 [ 747.718270] ? _raw_write_unlock_irq+0x29/0x50 [ 747.723820] ? ___preempt_schedule+0x16/0x18 [ 747.729193] ? ___preempt_schedule+0x16/0x18 [ 747.734574] do_exit+0xa11/0x14f0 [ 747.738880] ? mm_update_next_owner+0x590/0x590 [ 747.744525] ? debug_show_all_locks+0x3c0/0x3c0 [ 747.761448] ? ktime_get_coarse_real_ts64+0xeb/0x1c0 [ 747.767589] ? lockdep_hardirqs_on+0x1a6/0x290 [ 747.773154] ? check_chain_key+0x139/0x1f0 [ 747.778345] ? check_flags.part.35+0x240/0x240 [ 747.783908] ? __lock_acquire+0x2300/0x2300 [ 747.789171] ? _raw_spin_unlock_irqrestore+0x59/0x70 [ 747.795316] ? _raw_spin_unlock_irqrestore+0x59/0x70 [ 747.801457] ? do_raw_spin_unlock+0x10f/0x1e0 [ 747.806914] ? do_raw_spin_trylock+0x120/0x120 [ 747.812481] ? preempt_count_sub+0x14/0xc0 [ 747.817645] ? _raw_spin_unlock+0x2e/0x50 [ 747.822708] ? __handle_mm_fault+0x12db/0x1fa0 [ 747.828367] ? __pmd_alloc+0x2d0/0x2d0 [ 747.833143] ? check_noncircular+0x50/0x50 [ 747.838309] ? match_held_lock+0x7f/0x340 [ 747.843380] ? check_noncircular+0x50/0x50 [ 747.848561] ? handle_mm_fault+0x21a/0x5f0 [ 747.853730] ? check_flags.part.35+0x240/0x240 [ 747.859290] ? check_chain_key+0x139/0x1f0 [ 747.864474] ? __do_page_fault+0x40f/0x760 [ 747.869655] ? __audit_syscall_entry+0x4b/0x1f0 [ 747.875319] ? syscall_trace_enter+0x1d5/0x7b0 [ 747.880877] ? trace_raw_output_preemptirq_template+0x90/0x90 [ 747.887895] ? trace_raw_output_sys_exit+0x80/0x80 [ 747.893860] ? up_read+0x3b/0x90 [ 747.898142] ? stop_critical_timings+0x260/0x260 [ 747.903909] do_group_exit+0xe0/0x1c0 [ 747.908591] ? __x64_sys_exit+0x30/0x30 [ 747.913460] ? trace_raw_output_preemptirq_template+0x90/0x90 [ 747.920485] ? tracer_hardirqs_on+0x270/0x270 [ 747.925956] __x64_sys_exit_group+0x28/0x30 [ 747.931214] do_syscall_64+0x117/0x400 [ 747.935988] ? syscall_return_slowpath+0x2f0/0x2f0 [ 747.941931] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 747.947788] ? trace_hardirqs_on_caller+0x1d0/0x1d0 [ 747.953838] ? lockdep_sys_exit+0x16/0x8e [ 747.958915] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 747.964784] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 747.971021] RIP: 0033:0x7f572f154c68 [ 747.975606] Code: Bad RIP value. [ 747.979791] RSP: 002b:00007ffed2dfaa58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 747.989324] RAX: ffffffffffffffda RBX: 00007f572f431840 RCX: 00007f572f154c68 [ 747.997910] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 748.006495] RBP: 0000000000000001 R08: 00000000000000e7 R09: fffffffffffffee0 [ 748.015079] R10: 00007f572f4387e8 R11: 0000000000000246 R12: 00007f572f431840 [ 748.023664] R13: 000055a7f90f2c50 R14: 000055a7f96e2310 R15: 000055a7f96e2310 [ 748.032287] [ 748.034509] Allocated by task 2300: [ 748.038982] kasan_kmalloc+0xa0/0xd0 [ 748.043562] kmem_cache_alloc_node+0xf5/0x2e0 [ 748.049018] copy_process+0x1781/0x4790 [ 748.053884] _do_fork+0x166/0x9a0 [ 748.058163] do_syscall_64+0x117/0x400 [ 748.062943] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 748.069180] [ 748.071405] Freed by task 15395: [ 748.075591] __kasan_slab_free+0x130/0x180 [ 748.080752] kmem_cache_free+0xc2/0x310 [ 748.085619] free_task+0xea/0x130 [ 748.089901] __put_task_struct+0x177/0x230 [ 748.095063] finish_task_switch+0x51b/0x5d0 [ 748.100315] __schedule+0x506/0xfa0 [ 748.104791] schedule+0xca/0x260 [ 748.108978] futex_wait_queue_me+0x27e/0x420 [ 748.114333] futex_wait+0x251/0x550 [ 748.118814] do_futex+0x75b/0xf80 [ 748.123097] __x64_sys_futex+0x231/0x2a0 [ 748.128065] do_syscall_64+0x117/0x400 [ 748.132835] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 748.139066] [ 748.141289] The buggy address belongs to the object at ffff88a027698000 [ 748.141289] which belongs to the cache task_struct of size 12160 [ 748.156589] The buggy address is located 2272 bytes inside of [ 748.156589] 12160-byte region [ffff88a027698000, ffff88a02769af80) [ 748.171114] The buggy address belongs to the page: [ 748.177055] page:ffffea00809da600 count:1 mapcount:0 mapping:ffff888107d01e00 index:0x0 compound_mapcount: 0 [ 748.189136] flags: 0x57ffffc0008100(slab|head) [ 748.194688] raw: 0057ffffc0008100 ffffea00809a3200 0000000300000003 ffff888107d01e00 [ 748.204424] raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000 [ 748.214146] page dumped because: kasan: bad access detected [ 748.220976] [ 748.223197] Memory state around the buggy address: [ 748.229128] ffff88a027698780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.238271] ffff88a027698800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.247414] >ffff88a027698880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.256564] ^ [ 748.264267] ffff88a027698900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.273493] ffff88a027698980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 748.282630] ================================================================== Fixes: b086ff87251b4a4 ("connector: add parent pid and tgid to coredump and exit events") Signed-off-by: Zhang Yu <zhangyu31@baidu.com> Signed-off-by: Li RongQing <lirongqing@baidu.com> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: David S. Miller <davem@davemloft.net> 
proc_exit_connector() uses ->real_parent lockless. This is not
safe that its parent can go away at any moment, so use RCU to
protect it, and ensure that this task is not released.

[  747.624551] ==================================================================
[  747.632946] BUG: KASAN: use-after-free in proc_exit_connector+0x1f7/0x310
[  747.640686] Read of size 4 at addr ffff88a0276988e0 by task sshd/2882
[  747.648032]
[  747.649804] CPU: 11 PID: 2882 Comm: sshd Tainted: G            E     4.19.26-rc2 #11
[  747.658629] Hardware name: IBM x3550M4 -[7914OFV]-/00AM544, BIOS -[D7E142BUS-1.71]- 07/31/2014
[  747.668419] Call Trace:
[  747.671269]  dump_stack+0xf0/0x19b
[  747.675186]  ? show_regs_print_info+0x5/0x5
[  747.679988]  ? kmsg_dump_rewind_nolock+0x59/0x59
[  747.685302]  print_address_description+0x6a/0x270
[  747.691162]  kasan_report+0x258/0x380
[  747.695835]  ? proc_exit_connector+0x1f7/0x310
[  747.701402]  proc_exit_connector+0x1f7/0x310
[  747.706767]  ? proc_coredump_connector+0x2d0/0x2d0
[  747.712715]  ? _raw_write_unlock_irq+0x29/0x50
[  747.718270]  ? _raw_write_unlock_irq+0x29/0x50
[  747.723820]  ? ___preempt_schedule+0x16/0x18
[  747.729193]  ? ___preempt_schedule+0x16/0x18
[  747.734574]  do_exit+0xa11/0x14f0
[  747.738880]  ? mm_update_next_owner+0x590/0x590
[  747.744525]  ? debug_show_all_locks+0x3c0/0x3c0
[  747.761448]  ? ktime_get_coarse_real_ts64+0xeb/0x1c0
[  747.767589]  ? lockdep_hardirqs_on+0x1a6/0x290
[  747.773154]  ? check_chain_key+0x139/0x1f0
[  747.778345]  ? check_flags.part.35+0x240/0x240
[  747.783908]  ? __lock_acquire+0x2300/0x2300
[  747.789171]  ? _raw_spin_unlock_irqrestore+0x59/0x70
[  747.795316]  ? _raw_spin_unlock_irqrestore+0x59/0x70
[  747.801457]  ? do_raw_spin_unlock+0x10f/0x1e0
[  747.806914]  ? do_raw_spin_trylock+0x120/0x120
[  747.812481]  ? preempt_count_sub+0x14/0xc0
[  747.817645]  ? _raw_spin_unlock+0x2e/0x50
[  747.822708]  ? __handle_mm_fault+0x12db/0x1fa0
[  747.828367]  ? __pmd_alloc+0x2d0/0x2d0
[  747.833143]  ? check_noncircular+0x50/0x50
[  747.838309]  ? match_held_lock+0x7f/0x340
[  747.843380]  ? check_noncircular+0x50/0x50
[  747.848561]  ? handle_mm_fault+0x21a/0x5f0
[  747.853730]  ? check_flags.part.35+0x240/0x240
[  747.859290]  ? check_chain_key+0x139/0x1f0
[  747.864474]  ? __do_page_fault+0x40f/0x760
[  747.869655]  ? __audit_syscall_entry+0x4b/0x1f0
[  747.875319]  ? syscall_trace_enter+0x1d5/0x7b0
[  747.880877]  ? trace_raw_output_preemptirq_template+0x90/0x90
[  747.887895]  ? trace_raw_output_sys_exit+0x80/0x80
[  747.893860]  ? up_read+0x3b/0x90
[  747.898142]  ? stop_critical_timings+0x260/0x260
[  747.903909]  do_group_exit+0xe0/0x1c0
[  747.908591]  ? __x64_sys_exit+0x30/0x30
[  747.913460]  ? trace_raw_output_preemptirq_template+0x90/0x90
[  747.920485]  ? tracer_hardirqs_on+0x270/0x270
[  747.925956]  __x64_sys_exit_group+0x28/0x30
[  747.931214]  do_syscall_64+0x117/0x400
[  747.935988]  ? syscall_return_slowpath+0x2f0/0x2f0
[  747.941931]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[  747.947788]  ? trace_hardirqs_on_caller+0x1d0/0x1d0
[  747.953838]  ? lockdep_sys_exit+0x16/0x8e
[  747.958915]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[  747.964784]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  747.971021] RIP: 0033:0x7f572f154c68
[  747.975606] Code: Bad RIP value.
[  747.979791] RSP: 002b:00007ffed2dfaa58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
[  747.989324] RAX: ffffffffffffffda RBX: 00007f572f431840 RCX: 00007f572f154c68
[  747.997910] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001
[  748.006495] RBP: 0000000000000001 R08: 00000000000000e7 R09: fffffffffffffee0
[  748.015079] R10: 00007f572f4387e8 R11: 0000000000000246 R12: 00007f572f431840
[  748.023664] R13: 000055a7f90f2c50 R14: 000055a7f96e2310 R15: 000055a7f96e2310
[  748.032287]
[  748.034509] Allocated by task 2300:
[  748.038982]  kasan_kmalloc+0xa0/0xd0
[  748.043562]  kmem_cache_alloc_node+0xf5/0x2e0
[  748.049018]  copy_process+0x1781/0x4790
[  748.053884]  _do_fork+0x166/0x9a0
[  748.058163]  do_syscall_64+0x117/0x400
[  748.062943]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  748.069180]
[  748.071405] Freed by task 15395:
[  748.075591]  __kasan_slab_free+0x130/0x180
[  748.080752]  kmem_cache_free+0xc2/0x310
[  748.085619]  free_task+0xea/0x130
[  748.089901]  __put_task_struct+0x177/0x230
[  748.095063]  finish_task_switch+0x51b/0x5d0
[  748.100315]  __schedule+0x506/0xfa0
[  748.104791]  schedule+0xca/0x260
[  748.108978]  futex_wait_queue_me+0x27e/0x420
[  748.114333]  futex_wait+0x251/0x550
[  748.118814]  do_futex+0x75b/0xf80
[  748.123097]  __x64_sys_futex+0x231/0x2a0
[  748.128065]  do_syscall_64+0x117/0x400
[  748.132835]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  748.139066]
[  748.141289] The buggy address belongs to the object at ffff88a027698000
[  748.141289]  which belongs to the cache task_struct of size 12160
[  748.156589] The buggy address is located 2272 bytes inside of
[  748.156589]  12160-byte region [ffff88a027698000, ffff88a02769af80)
[  748.171114] The buggy address belongs to the page:
[  748.177055] page:ffffea00809da600 count:1 mapcount:0 mapping:ffff888107d01e00 index:0x0 compound_mapcount: 0
[  748.189136] flags: 0x57ffffc0008100(slab|head)
[  748.194688] raw: 0057ffffc0008100 ffffea00809a3200 0000000300000003 ffff888107d01e00
[  748.204424] raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
[  748.214146] page dumped because: kasan: bad access detected
[  748.220976]
[  748.223197] Memory state around the buggy address:
[  748.229128]  ffff88a027698780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  748.238271]  ffff88a027698800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  748.247414] >ffff88a027698880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  748.256564]                                                        ^
[  748.264267]  ffff88a027698900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  748.273493]  ffff88a027698980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  748.282630] ==================================================================

Fixes: b086ff87251b4a4 ("connector: add parent pid and tgid to coredump and exit events")
Signed-off-by: Zhang Yu <zhangyu31@baidu.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
connector: add parent pid and tgid to coredump and exit events 2018-05-01T18:25:37+00:00 Stefan Strogin sstrogin@cisco.com 2018-04-30T22:04:29+00:00 b086ff87251b4a4c147bc3af20369514e9d0d9ad The intention is to get notified of process failures as soon as possible, before a possible core dumping (which could be very long) (e.g. in some process-manager). Coredump and exit process events are perfect for such use cases (see 2b5faa4c553f "connector: Added coredumping event to the process connector"). The problem is that for now the process-manager cannot know the parent of a dying process using connectors. This could be useful if the process-manager should monitor for failures only children of certain parents, so we could filter the coredump and exit events by parent process and/or thread ID. Add parent pid and tgid to coredump and exit process connectors event data. Signed-off-by: Stefan Strogin <sstrogin@cisco.com> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: David S. Miller <davem@davemloft.net> 
The intention is to get notified of process failures as soon
as possible, before a possible core dumping (which could be very long)
(e.g. in some process-manager). Coredump and exit process events
are perfect for such use cases (see 2b5faa4c553f "connector: Added
coredumping event to the process connector").

The problem is that for now the process-manager cannot know the parent
of a dying process using connectors. This could be useful if the
process-manager should monitor for failures only children of certain
parents, so we could filter the coredump and exit events by parent
process and/or thread ID.

Add parent pid and tgid to coredump and exit process connectors event
data.

Signed-off-by: Stefan Strogin <sstrogin@cisco.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>