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Wireguard fails with ipv6 and Ubuntu 22 #28

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withinboredom opened this issue Jun 27, 2022 · 2 comments
Open

Wireguard fails with ipv6 and Ubuntu 22 #28

withinboredom opened this issue Jun 27, 2022 · 2 comments

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@withinboredom
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After some digging around I found this issue for another kernel. It appears CONFIG_NFT_FIB_IPV6 must be set.

withinboredom@Legion:~$ zcat /proc/config.gz | grep CONFIG_NFT_FIB_IPV6
# CONFIG_NFT_FIB_IPV6 is not set

The error looks like this:

withinboredom@Legion:~$ sudo wg-quick up ~/wsl-wg.conf
[#] ip link add wsl-wg type wireguard
[#] wg setconf wsl-wg /dev/fd/63
[#] ip -6 address add PREFIX::1005/128 dev wsl-wg
[#] ip link set mtu 1340 up dev wsl-wg
[#] wg set wsl-wg fwmark 51820
[#] ip -6 route add ::/0 dev wsl-wg table 51820
[#] ip -6 rule add not fwmark 51820 table 51820
[#] ip -6 rule add table main suppress_prefixlength 0
[#] nft -f /dev/fd/63
/dev/fd/63:5:93-106: Error: Could not process rule: No such file or directory

/dev/fd/63:6:69-84: Error: Could not process rule: No such file or directory

/dev/fd/63:7:71-77: Error: Could not process rule: No such file or directory

[#] ip -6 rule delete table 51820
[#] ip -6 rule delete table main suppress_prefixlength 0
[#] ip link delete dev wsl-wg
@nathanchance
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Can you try this image and see if it works? You'll need to decompress it with gzip first.

nathanchance pushed a commit that referenced this issue Jun 27, 2022
kasan detects access beyond the end of the xibm->bitmap allocation:

BUG: KASAN: slab-out-of-bounds in _find_first_zero_bit+0x40/0x140
Read of size 8 at addr c00000001d1d0118 by task swapper/0/1

CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc2-00001-g90df023b36dd #28
Call Trace:
[c00000001d98f770] [c0000000012baab8] dump_stack_lvl+0xac/0x108 (unreliable)
[c00000001d98f7b0] [c00000000068faac] print_report+0x37c/0x710
[c00000001d98f880] [c0000000006902c0] kasan_report+0x110/0x354
[c00000001d98f950] [c000000000692324] __asan_load8+0xa4/0xe0
[c00000001d98f970] [c0000000011c6ed0] _find_first_zero_bit+0x40/0x140
[c00000001d98f9b0] [c0000000000dbfbc] xive_spapr_get_ipi+0xcc/0x260
[c00000001d98fa70] [c0000000000d6d28] xive_setup_cpu_ipi+0x1e8/0x450
[c00000001d98fb30] [c000000004032a20] pSeries_smp_probe+0x5c/0x118
[c00000001d98fb60] [c000000004018b44] smp_prepare_cpus+0x944/0x9ac
[c00000001d98fc90] [c000000004009f9c] kernel_init_freeable+0x2d4/0x640
[c00000001d98fd90] [c0000000000131e8] kernel_init+0x28/0x1d0
[c00000001d98fe10] [c00000000000cd54] ret_from_kernel_thread+0x5c/0x64

Allocated by task 0:
 kasan_save_stack+0x34/0x70
 __kasan_kmalloc+0xb4/0xf0
 __kmalloc+0x268/0x540
 xive_spapr_init+0x4d0/0x77c
 pseries_init_irq+0x40/0x27c
 init_IRQ+0x44/0x84
 start_kernel+0x2a4/0x538
 start_here_common+0x1c/0x20

The buggy address belongs to the object at c00000001d1d0118
 which belongs to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes inside of
 8-byte region [c00000001d1d0118, c00000001d1d0120)

The buggy address belongs to the physical page:
page:c00c000000074740 refcount:1 mapcount:0 mapping:0000000000000000 index:0xc00000001d1d0558 pfn:0x1d1d
flags: 0x7ffff000000200(slab|node=0|zone=0|lastcpupid=0x7ffff)
raw: 007ffff000000200 c00000001d0003c8 c00000001d0003c8 c00000001d010480
raw: c00000001d1d0558 0000000001e1000a 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 c00000001d1d0000: fc 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 c00000001d1d0080: fc fc 00 fc fc fc fc fc fc fc fc fc fc fc fc fc
>c00000001d1d0100: fc fc fc 02 fc fc fc fc fc fc fc fc fc fc fc fc
                            ^
 c00000001d1d0180: fc fc fc fc 04 fc fc fc fc fc fc fc fc fc fc fc
 c00000001d1d0200: fc fc fc fc fc 04 fc fc fc fc fc fc fc fc fc fc

This happens because the allocation uses the wrong unit (bits) when it
should pass (BITS_TO_LONGS(count) * sizeof(long)) or equivalent. With small
numbers of bits, the allocated object can be smaller than sizeof(long),
which results in invalid accesses.

Use bitmap_zalloc() to allocate and initialize the irq bitmap, paired with
bitmap_free() for consistency.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220623182509.3985625-1-nathanl@linux.ibm.com
@azumukupoe
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Can you try this image and see if it works? You'll need to decompress it with gzip first.

I can't start docker with it
is it just me?

nathanchance pushed a commit that referenced this issue Jul 28, 2022
This fixes the following trace which is caused by hci_rx_work starting up
*after* the final channel reference has been put() during sock_close() but
*before* the references to the channel have been destroyed, so instead
the code now rely on kref_get_unless_zero/l2cap_chan_hold_unless_zero to
prevent referencing a channel that is about to be destroyed.

  refcount_t: increment on 0; use-after-free.
  BUG: KASAN: use-after-free in refcount_dec_and_test+0x20/0xd0
  Read of size 4 at addr ffffffc114f5bf18 by task kworker/u17:14/705

  CPU: 4 PID: 705 Comm: kworker/u17:14 Tainted: G S      W
  4.14.234-00003-g1fb6d0bd49a4-dirty #28
  Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150
  Google Inc. MSM sm8150 Flame DVT (DT)
  Workqueue: hci0 hci_rx_work
  Call trace:
   dump_backtrace+0x0/0x378
   show_stack+0x20/0x2c
   dump_stack+0x124/0x148
   print_address_description+0x80/0x2e8
   __kasan_report+0x168/0x188
   kasan_report+0x10/0x18
   __asan_load4+0x84/0x8c
   refcount_dec_and_test+0x20/0xd0
   l2cap_chan_put+0x48/0x12c
   l2cap_recv_frame+0x4770/0x6550
   l2cap_recv_acldata+0x44c/0x7a4
   hci_acldata_packet+0x100/0x188
   hci_rx_work+0x178/0x23c
   process_one_work+0x35c/0x95c
   worker_thread+0x4cc/0x960
   kthread+0x1a8/0x1c4
   ret_from_fork+0x10/0x18

Cc: stable@kernel.org
Reported-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Tested-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
nathanchance pushed a commit that referenced this issue Aug 15, 2022
The assumption in __disable_kprobe() is wrong, and it could try to disarm
an already disarmed kprobe and fire the WARN_ONCE() below. [0]  We can
easily reproduce this issue.

1. Write 0 to /sys/kernel/debug/kprobes/enabled.

  # echo 0 > /sys/kernel/debug/kprobes/enabled

2. Run execsnoop.  At this time, one kprobe is disabled.

  # /usr/share/bcc/tools/execsnoop &
  [1] 2460
  PCOMM            PID    PPID   RET ARGS

  # cat /sys/kernel/debug/kprobes/list
  ffffffff91345650  r  __x64_sys_execve+0x0    [FTRACE]
  ffffffff91345650  k  __x64_sys_execve+0x0    [DISABLED][FTRACE]

3. Write 1 to /sys/kernel/debug/kprobes/enabled, which changes
   kprobes_all_disarmed to false but does not arm the disabled kprobe.

  # echo 1 > /sys/kernel/debug/kprobes/enabled

  # cat /sys/kernel/debug/kprobes/list
  ffffffff91345650  r  __x64_sys_execve+0x0    [FTRACE]
  ffffffff91345650  k  __x64_sys_execve+0x0    [DISABLED][FTRACE]

4. Kill execsnoop, when __disable_kprobe() calls disarm_kprobe() for the
   disabled kprobe and hits the WARN_ONCE() in __disarm_kprobe_ftrace().

  # fg
  /usr/share/bcc/tools/execsnoop
  ^C

Actually, WARN_ONCE() is fired twice, and __unregister_kprobe_top() misses
some cleanups and leaves the aggregated kprobe in the hash table.  Then,
__unregister_trace_kprobe() initialises tk->rp.kp.list and creates an
infinite loop like this.

  aggregated kprobe.list -> kprobe.list -.
                                     ^    |
                                     '.__.'

In this situation, these commands fall into the infinite loop and result
in RCU stall or soft lockup.

  cat /sys/kernel/debug/kprobes/list : show_kprobe_addr() enters into the
                                       infinite loop with RCU.

  /usr/share/bcc/tools/execsnoop : warn_kprobe_rereg() holds kprobe_mutex,
                                   and __get_valid_kprobe() is stuck in
				   the loop.

To avoid the issue, make sure we don't call disarm_kprobe() for disabled
kprobes.

[0]
Failed to disarm kprobe-ftrace at __x64_sys_execve+0x0/0x40 (error -2)
WARNING: CPU: 6 PID: 2460 at kernel/kprobes.c:1130 __disarm_kprobe_ftrace.isra.19 (kernel/kprobes.c:1129)
Modules linked in: ena
CPU: 6 PID: 2460 Comm: execsnoop Not tainted 5.19.0+ #28
Hardware name: Amazon EC2 c5.2xlarge/, BIOS 1.0 10/16/2017
RIP: 0010:__disarm_kprobe_ftrace.isra.19 (kernel/kprobes.c:1129)
Code: 24 8b 02 eb c1 80 3d c4 83 f2 01 00 75 d4 48 8b 75 00 89 c2 48 c7 c7 90 fa 0f 92 89 04 24 c6 05 ab 83 01 e8 e4 94 f0 ff <0f> 0b 8b 04 24 eb b1 89 c6 48 c7 c7 60 fa 0f 92 89 04 24 e8 cc 94
RSP: 0018:ffff9e6ec154bd98 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffffff930f7b00 RCX: 0000000000000001
RDX: 0000000080000001 RSI: ffffffff921461c5 RDI: 00000000ffffffff
RBP: ffff89c504286da8 R08: 0000000000000000 R09: c0000000fffeffff
R10: 0000000000000000 R11: ffff9e6ec154bc28 R12: ffff89c502394e40
R13: ffff89c502394c00 R14: ffff9e6ec154bc00 R15: 0000000000000000
FS:  00007fe800398740(0000) GS:ffff89c812d80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00057f010 CR3: 0000000103b54006 CR4: 00000000007706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
 __disable_kprobe (kernel/kprobes.c:1716)
 disable_kprobe (kernel/kprobes.c:2392)
 __disable_trace_kprobe (kernel/trace/trace_kprobe.c:340)
 disable_trace_kprobe (kernel/trace/trace_kprobe.c:429)
 perf_trace_event_unreg.isra.2 (./include/linux/tracepoint.h:93 kernel/trace/trace_event_perf.c:168)
 perf_kprobe_destroy (kernel/trace/trace_event_perf.c:295)
 _free_event (kernel/events/core.c:4971)
 perf_event_release_kernel (kernel/events/core.c:5176)
 perf_release (kernel/events/core.c:5186)
 __fput (fs/file_table.c:321)
 task_work_run (./include/linux/sched.h:2056 (discriminator 1) kernel/task_work.c:179 (discriminator 1))
 exit_to_user_mode_prepare (./include/linux/resume_user_mode.h:49 kernel/entry/common.c:169 kernel/entry/common.c:201)
 syscall_exit_to_user_mode (./arch/x86/include/asm/jump_label.h:55 ./arch/x86/include/asm/nospec-branch.h:384 ./arch/x86/include/asm/entry-common.h:94 kernel/entry/common.c:133 kernel/entry/common.c:296)
 do_syscall_64 (arch/x86/entry/common.c:87)
 entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
RIP: 0033:0x7fe7ff210654
Code: 15 79 89 20 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb be 0f 1f 00 8b 05 9a cd 20 00 48 63 ff 85 c0 75 11 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 3a f3 c3 48 83 ec 18 48 89 7c 24 08 e8 34 fc
RSP: 002b:00007ffdbd1d3538 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000008 RCX: 00007fe7ff210654
RDX: 0000000000000000 RSI: 0000000000002401 RDI: 0000000000000008
RBP: 0000000000000000 R08: 94ae31d6fda838a4 R0900007fe8001c9d30
R10: 00007ffdbd1d34b0 R11: 0000000000000246 R12: 00007ffdbd1d3600
R13: 0000000000000000 R14: fffffffffffffffc R15: 00007ffdbd1d3560
</TASK>

Link: https://lkml.kernel.org/r/20220813020509.90805-1-kuniyu@amazon.com
Fixes: 69d54b9 ("kprobes: makes kprobes/enabled works correctly for optimized kprobes.")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reported-by: Ayushman Dutta <ayudutta@amazon.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Kuniyuki Iwashima <kuni1840@gmail.com>
Cc: Ayushman Dutta <ayudutta@amazon.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
nathanchance pushed a commit that referenced this issue Aug 16, 2022
The assumption in __disable_kprobe() is wrong, and it could try to disarm
an already disarmed kprobe and fire the WARN_ONCE() below. [0]  We can
easily reproduce this issue.

1. Write 0 to /sys/kernel/debug/kprobes/enabled.

  # echo 0 > /sys/kernel/debug/kprobes/enabled

2. Run execsnoop.  At this time, one kprobe is disabled.

  # /usr/share/bcc/tools/execsnoop &
  [1] 2460
  PCOMM            PID    PPID   RET ARGS

  # cat /sys/kernel/debug/kprobes/list
  ffffffff91345650  r  __x64_sys_execve+0x0    [FTRACE]
  ffffffff91345650  k  __x64_sys_execve+0x0    [DISABLED][FTRACE]

3. Write 1 to /sys/kernel/debug/kprobes/enabled, which changes
   kprobes_all_disarmed to false but does not arm the disabled kprobe.

  # echo 1 > /sys/kernel/debug/kprobes/enabled

  # cat /sys/kernel/debug/kprobes/list
  ffffffff91345650  r  __x64_sys_execve+0x0    [FTRACE]
  ffffffff91345650  k  __x64_sys_execve+0x0    [DISABLED][FTRACE]

4. Kill execsnoop, when __disable_kprobe() calls disarm_kprobe() for the
   disabled kprobe and hits the WARN_ONCE() in __disarm_kprobe_ftrace().

  # fg
  /usr/share/bcc/tools/execsnoop
  ^C

Actually, WARN_ONCE() is fired twice, and __unregister_kprobe_top() misses
some cleanups and leaves the aggregated kprobe in the hash table.  Then,
__unregister_trace_kprobe() initialises tk->rp.kp.list and creates an
infinite loop like this.

  aggregated kprobe.list -> kprobe.list -.
                                     ^    |
                                     '.__.'

In this situation, these commands fall into the infinite loop and result
in RCU stall or soft lockup.

  cat /sys/kernel/debug/kprobes/list : show_kprobe_addr() enters into the
                                       infinite loop with RCU.

  /usr/share/bcc/tools/execsnoop : warn_kprobe_rereg() holds kprobe_mutex,
                                   and __get_valid_kprobe() is stuck in
				   the loop.

To avoid the issue, make sure we don't call disarm_kprobe() for disabled
kprobes.

[0]
Failed to disarm kprobe-ftrace at __x64_sys_execve+0x0/0x40 (error -2)
WARNING: CPU: 6 PID: 2460 at kernel/kprobes.c:1130 __disarm_kprobe_ftrace.isra.19 (kernel/kprobes.c:1129)
Modules linked in: ena
CPU: 6 PID: 2460 Comm: execsnoop Not tainted 5.19.0+ #28
Hardware name: Amazon EC2 c5.2xlarge/, BIOS 1.0 10/16/2017
RIP: 0010:__disarm_kprobe_ftrace.isra.19 (kernel/kprobes.c:1129)
Code: 24 8b 02 eb c1 80 3d c4 83 f2 01 00 75 d4 48 8b 75 00 89 c2 48 c7 c7 90 fa 0f 92 89 04 24 c6 05 ab 83 01 e8 e4 94 f0 ff <0f> 0b 8b 04 24 eb b1 89 c6 48 c7 c7 60 fa 0f 92 89 04 24 e8 cc 94
RSP: 0018:ffff9e6ec154bd98 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffffff930f7b00 RCX: 0000000000000001
RDX: 0000000080000001 RSI: ffffffff921461c5 RDI: 00000000ffffffff
RBP: ffff89c504286da8 R08: 0000000000000000 R09: c0000000fffeffff
R10: 0000000000000000 R11: ffff9e6ec154bc28 R12: ffff89c502394e40
R13: ffff89c502394c00 R14: ffff9e6ec154bc00 R15: 0000000000000000
FS:  00007fe800398740(0000) GS:ffff89c812d80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00057f010 CR3: 0000000103b54006 CR4: 00000000007706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
 __disable_kprobe (kernel/kprobes.c:1716)
 disable_kprobe (kernel/kprobes.c:2392)
 __disable_trace_kprobe (kernel/trace/trace_kprobe.c:340)
 disable_trace_kprobe (kernel/trace/trace_kprobe.c:429)
 perf_trace_event_unreg.isra.2 (./include/linux/tracepoint.h:93 kernel/trace/trace_event_perf.c:168)
 perf_kprobe_destroy (kernel/trace/trace_event_perf.c:295)
 _free_event (kernel/events/core.c:4971)
 perf_event_release_kernel (kernel/events/core.c:5176)
 perf_release (kernel/events/core.c:5186)
 __fput (fs/file_table.c:321)
 task_work_run (./include/linux/sched.h:2056 (discriminator 1) kernel/task_work.c:179 (discriminator 1))
 exit_to_user_mode_prepare (./include/linux/resume_user_mode.h:49 kernel/entry/common.c:169 kernel/entry/common.c:201)
 syscall_exit_to_user_mode (./arch/x86/include/asm/jump_label.h:55 ./arch/x86/include/asm/nospec-branch.h:384 ./arch/x86/include/asm/entry-common.h:94 kernel/entry/common.c:133 kernel/entry/common.c:296)
 do_syscall_64 (arch/x86/entry/common.c:87)
 entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
RIP: 0033:0x7fe7ff210654
Code: 15 79 89 20 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb be 0f 1f 00 8b 05 9a cd 20 00 48 63 ff 85 c0 75 11 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 3a f3 c3 48 83 ec 18 48 89 7c 24 08 e8 34 fc
RSP: 002b:00007ffdbd1d3538 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000008 RCX: 00007fe7ff210654
RDX: 0000000000000000 RSI: 0000000000002401 RDI: 0000000000000008
RBP: 0000000000000000 R08: 94ae31d6fda838a4 R0900007fe8001c9d30
R10: 00007ffdbd1d34b0 R11: 0000000000000246 R12: 00007ffdbd1d3600
R13: 0000000000000000 R14: fffffffffffffffc R15: 00007ffdbd1d3560
</TASK>

Link: https://lkml.kernel.org/r/20220813020509.90805-1-kuniyu@amazon.com
Fixes: 69d54b9 ("kprobes: makes kprobes/enabled works correctly for optimized kprobes.")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reported-by: Ayushman Dutta <ayudutta@amazon.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Kuniyuki Iwashima <kuni1840@gmail.com>
Cc: Ayushman Dutta <ayudutta@amazon.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
nathanchance pushed a commit that referenced this issue Aug 18, 2022
The assumption in __disable_kprobe() is wrong, and it could try to disarm
an already disarmed kprobe and fire the WARN_ONCE() below. [0]  We can
easily reproduce this issue.

1. Write 0 to /sys/kernel/debug/kprobes/enabled.

  # echo 0 > /sys/kernel/debug/kprobes/enabled

2. Run execsnoop.  At this time, one kprobe is disabled.

  # /usr/share/bcc/tools/execsnoop &
  [1] 2460
  PCOMM            PID    PPID   RET ARGS

  # cat /sys/kernel/debug/kprobes/list
  ffffffff91345650  r  __x64_sys_execve+0x0    [FTRACE]
  ffffffff91345650  k  __x64_sys_execve+0x0    [DISABLED][FTRACE]

3. Write 1 to /sys/kernel/debug/kprobes/enabled, which changes
   kprobes_all_disarmed to false but does not arm the disabled kprobe.

  # echo 1 > /sys/kernel/debug/kprobes/enabled

  # cat /sys/kernel/debug/kprobes/list
  ffffffff91345650  r  __x64_sys_execve+0x0    [FTRACE]
  ffffffff91345650  k  __x64_sys_execve+0x0    [DISABLED][FTRACE]

4. Kill execsnoop, when __disable_kprobe() calls disarm_kprobe() for the
   disabled kprobe and hits the WARN_ONCE() in __disarm_kprobe_ftrace().

  # fg
  /usr/share/bcc/tools/execsnoop
  ^C

Actually, WARN_ONCE() is fired twice, and __unregister_kprobe_top() misses
some cleanups and leaves the aggregated kprobe in the hash table.  Then,
__unregister_trace_kprobe() initialises tk->rp.kp.list and creates an
infinite loop like this.

  aggregated kprobe.list -> kprobe.list -.
                                     ^    |
                                     '.__.'

In this situation, these commands fall into the infinite loop and result
in RCU stall or soft lockup.

  cat /sys/kernel/debug/kprobes/list : show_kprobe_addr() enters into the
                                       infinite loop with RCU.

  /usr/share/bcc/tools/execsnoop : warn_kprobe_rereg() holds kprobe_mutex,
                                   and __get_valid_kprobe() is stuck in
				   the loop.

To avoid the issue, make sure we don't call disarm_kprobe() for disabled
kprobes.

[0]
Failed to disarm kprobe-ftrace at __x64_sys_execve+0x0/0x40 (error -2)
WARNING: CPU: 6 PID: 2460 at kernel/kprobes.c:1130 __disarm_kprobe_ftrace.isra.19 (kernel/kprobes.c:1129)
Modules linked in: ena
CPU: 6 PID: 2460 Comm: execsnoop Not tainted 5.19.0+ #28
Hardware name: Amazon EC2 c5.2xlarge/, BIOS 1.0 10/16/2017
RIP: 0010:__disarm_kprobe_ftrace.isra.19 (kernel/kprobes.c:1129)
Code: 24 8b 02 eb c1 80 3d c4 83 f2 01 00 75 d4 48 8b 75 00 89 c2 48 c7 c7 90 fa 0f 92 89 04 24 c6 05 ab 83 01 e8 e4 94 f0 ff <0f> 0b 8b 04 24 eb b1 89 c6 48 c7 c7 60 fa 0f 92 89 04 24 e8 cc 94
RSP: 0018:ffff9e6ec154bd98 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffffff930f7b00 RCX: 0000000000000001
RDX: 0000000080000001 RSI: ffffffff921461c5 RDI: 00000000ffffffff
RBP: ffff89c504286da8 R08: 0000000000000000 R09: c0000000fffeffff
R10: 0000000000000000 R11: ffff9e6ec154bc28 R12: ffff89c502394e40
R13: ffff89c502394c00 R14: ffff9e6ec154bc00 R15: 0000000000000000
FS:  00007fe800398740(0000) GS:ffff89c812d80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00057f010 CR3: 0000000103b54006 CR4: 00000000007706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
 __disable_kprobe (kernel/kprobes.c:1716)
 disable_kprobe (kernel/kprobes.c:2392)
 __disable_trace_kprobe (kernel/trace/trace_kprobe.c:340)
 disable_trace_kprobe (kernel/trace/trace_kprobe.c:429)
 perf_trace_event_unreg.isra.2 (./include/linux/tracepoint.h:93 kernel/trace/trace_event_perf.c:168)
 perf_kprobe_destroy (kernel/trace/trace_event_perf.c:295)
 _free_event (kernel/events/core.c:4971)
 perf_event_release_kernel (kernel/events/core.c:5176)
 perf_release (kernel/events/core.c:5186)
 __fput (fs/file_table.c:321)
 task_work_run (./include/linux/sched.h:2056 (discriminator 1) kernel/task_work.c:179 (discriminator 1))
 exit_to_user_mode_prepare (./include/linux/resume_user_mode.h:49 kernel/entry/common.c:169 kernel/entry/common.c:201)
 syscall_exit_to_user_mode (./arch/x86/include/asm/jump_label.h:55 ./arch/x86/include/asm/nospec-branch.h:384 ./arch/x86/include/asm/entry-common.h:94 kernel/entry/common.c:133 kernel/entry/common.c:296)
 do_syscall_64 (arch/x86/entry/common.c:87)
 entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
RIP: 0033:0x7fe7ff210654
Code: 15 79 89 20 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb be 0f 1f 00 8b 05 9a cd 20 00 48 63 ff 85 c0 75 11 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 3a f3 c3 48 83 ec 18 48 89 7c 24 08 e8 34 fc
RSP: 002b:00007ffdbd1d3538 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000008 RCX: 00007fe7ff210654
RDX: 0000000000000000 RSI: 0000000000002401 RDI: 0000000000000008
RBP: 0000000000000000 R08: 94ae31d6fda838a4 R0900007fe8001c9d30
R10: 00007ffdbd1d34b0 R11: 0000000000000246 R12: 00007ffdbd1d3600
R13: 0000000000000000 R14: fffffffffffffffc R15: 00007ffdbd1d3560
</TASK>

Link: https://lkml.kernel.org/r/20220813020509.90805-1-kuniyu@amazon.com
Fixes: 69d54b9 ("kprobes: makes kprobes/enabled works correctly for optimized kprobes.")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reported-by: Ayushman Dutta <ayudutta@amazon.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Kuniyuki Iwashima <kuni1840@gmail.com>
Cc: Ayushman Dutta <ayudutta@amazon.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
nathanchance pushed a commit that referenced this issue Aug 22, 2022
The assumption in __disable_kprobe() is wrong, and it could try to disarm
an already disarmed kprobe and fire the WARN_ONCE() below. [0]  We can
easily reproduce this issue.

1. Write 0 to /sys/kernel/debug/kprobes/enabled.

  # echo 0 > /sys/kernel/debug/kprobes/enabled

2. Run execsnoop.  At this time, one kprobe is disabled.

  # /usr/share/bcc/tools/execsnoop &
  [1] 2460
  PCOMM            PID    PPID   RET ARGS

  # cat /sys/kernel/debug/kprobes/list
  ffffffff91345650  r  __x64_sys_execve+0x0    [FTRACE]
  ffffffff91345650  k  __x64_sys_execve+0x0    [DISABLED][FTRACE]

3. Write 1 to /sys/kernel/debug/kprobes/enabled, which changes
   kprobes_all_disarmed to false but does not arm the disabled kprobe.

  # echo 1 > /sys/kernel/debug/kprobes/enabled

  # cat /sys/kernel/debug/kprobes/list
  ffffffff91345650  r  __x64_sys_execve+0x0    [FTRACE]
  ffffffff91345650  k  __x64_sys_execve+0x0    [DISABLED][FTRACE]

4. Kill execsnoop, when __disable_kprobe() calls disarm_kprobe() for the
   disabled kprobe and hits the WARN_ONCE() in __disarm_kprobe_ftrace().

  # fg
  /usr/share/bcc/tools/execsnoop
  ^C

Actually, WARN_ONCE() is fired twice, and __unregister_kprobe_top() misses
some cleanups and leaves the aggregated kprobe in the hash table.  Then,
__unregister_trace_kprobe() initialises tk->rp.kp.list and creates an
infinite loop like this.

  aggregated kprobe.list -> kprobe.list -.
                                     ^    |
                                     '.__.'

In this situation, these commands fall into the infinite loop and result
in RCU stall or soft lockup.

  cat /sys/kernel/debug/kprobes/list : show_kprobe_addr() enters into the
                                       infinite loop with RCU.

  /usr/share/bcc/tools/execsnoop : warn_kprobe_rereg() holds kprobe_mutex,
                                   and __get_valid_kprobe() is stuck in
				   the loop.

To avoid the issue, make sure we don't call disarm_kprobe() for disabled
kprobes.

[0]
Failed to disarm kprobe-ftrace at __x64_sys_execve+0x0/0x40 (error -2)
WARNING: CPU: 6 PID: 2460 at kernel/kprobes.c:1130 __disarm_kprobe_ftrace.isra.19 (kernel/kprobes.c:1129)
Modules linked in: ena
CPU: 6 PID: 2460 Comm: execsnoop Not tainted 5.19.0+ #28
Hardware name: Amazon EC2 c5.2xlarge/, BIOS 1.0 10/16/2017
RIP: 0010:__disarm_kprobe_ftrace.isra.19 (kernel/kprobes.c:1129)
Code: 24 8b 02 eb c1 80 3d c4 83 f2 01 00 75 d4 48 8b 75 00 89 c2 48 c7 c7 90 fa 0f 92 89 04 24 c6 05 ab 83 01 e8 e4 94 f0 ff <0f> 0b 8b 04 24 eb b1 89 c6 48 c7 c7 60 fa 0f 92 89 04 24 e8 cc 94
RSP: 0018:ffff9e6ec154bd98 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffffff930f7b00 RCX: 0000000000000001
RDX: 0000000080000001 RSI: ffffffff921461c5 RDI: 00000000ffffffff
RBP: ffff89c504286da8 R08: 0000000000000000 R09: c0000000fffeffff
R10: 0000000000000000 R11: ffff9e6ec154bc28 R12: ffff89c502394e40
R13: ffff89c502394c00 R14: ffff9e6ec154bc00 R15: 0000000000000000
FS:  00007fe800398740(0000) GS:ffff89c812d80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00057f010 CR3: 0000000103b54006 CR4: 00000000007706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
 __disable_kprobe (kernel/kprobes.c:1716)
 disable_kprobe (kernel/kprobes.c:2392)
 __disable_trace_kprobe (kernel/trace/trace_kprobe.c:340)
 disable_trace_kprobe (kernel/trace/trace_kprobe.c:429)
 perf_trace_event_unreg.isra.2 (./include/linux/tracepoint.h:93 kernel/trace/trace_event_perf.c:168)
 perf_kprobe_destroy (kernel/trace/trace_event_perf.c:295)
 _free_event (kernel/events/core.c:4971)
 perf_event_release_kernel (kernel/events/core.c:5176)
 perf_release (kernel/events/core.c:5186)
 __fput (fs/file_table.c:321)
 task_work_run (./include/linux/sched.h:2056 (discriminator 1) kernel/task_work.c:179 (discriminator 1))
 exit_to_user_mode_prepare (./include/linux/resume_user_mode.h:49 kernel/entry/common.c:169 kernel/entry/common.c:201)
 syscall_exit_to_user_mode (./arch/x86/include/asm/jump_label.h:55 ./arch/x86/include/asm/nospec-branch.h:384 ./arch/x86/include/asm/entry-common.h:94 kernel/entry/common.c:133 kernel/entry/common.c:296)
 do_syscall_64 (arch/x86/entry/common.c:87)
 entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
RIP: 0033:0x7fe7ff210654
Code: 15 79 89 20 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb be 0f 1f 00 8b 05 9a cd 20 00 48 63 ff 85 c0 75 11 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 3a f3 c3 48 83 ec 18 48 89 7c 24 08 e8 34 fc
RSP: 002b:00007ffdbd1d3538 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000008 RCX: 00007fe7ff210654
RDX: 0000000000000000 RSI: 0000000000002401 RDI: 0000000000000008
RBP: 0000000000000000 R08: 94ae31d6fda838a4 R0900007fe8001c9d30
R10: 00007ffdbd1d34b0 R11: 0000000000000246 R12: 00007ffdbd1d3600
R13: 0000000000000000 R14: fffffffffffffffc R15: 00007ffdbd1d3560
</TASK>

Link: https://lkml.kernel.org/r/20220813020509.90805-1-kuniyu@amazon.com
Fixes: 69d54b9 ("kprobes: makes kprobes/enabled works correctly for optimized kprobes.")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reported-by: Ayushman Dutta <ayudutta@amazon.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Kuniyuki Iwashima <kuni1840@gmail.com>
Cc: Ayushman Dutta <ayudutta@amazon.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
nathanchance pushed a commit that referenced this issue Oct 4, 2022
This adds a sanity check for the i_op pointer of the inode which is
returned after reading Root directory MFT record. We should check the
i_op is valid before trying to create the root dentry, otherwise we may
encounter a NPD while mounting a image with a funny Root directory MFT
record.

[  114.484325] BUG: kernel NULL pointer dereference, address: 0000000000000008
[  114.484811] #PF: supervisor read access in kernel mode
[  114.485084] #PF: error_code(0x0000) - not-present page
[  114.485606] PGD 0 P4D 0
[  114.485975] Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI
[  114.486570] CPU: 0 PID: 237 Comm: mount Tainted: G    B              6.0.0-rc4 #28
[  114.486977] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[  114.488169] RIP: 0010:d_flags_for_inode+0xe0/0x110
[  114.488816] Code: 24 f7 ff 49 83 3e 00 74 41 41 83 cd 02 66 44 89 6b 02 eb 92 48 8d 7b 20 e8 6d 24 f7 ff 4c 8b 73 20 49 8d 7e 08 e8 60 241
[  114.490326] RSP: 0018:ffff8880065e7aa8 EFLAGS: 00000296
[  114.490695] RAX: 0000000000000001 RBX: ffff888008ccd750 RCX: ffffffff84af2aea
[  114.490986] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff87abd020
[  114.491364] RBP: ffff8880065e7ac8 R08: 0000000000000001 R09: fffffbfff0f57a05
[  114.491675] R10: ffffffff87abd027 R11: fffffbfff0f57a04 R12: 0000000000000000
[  114.491954] R13: 0000000000000008 R14: 0000000000000000 R15: ffff888008ccd750
[  114.492397] FS:  00007fdc8a627e40(0000) GS:ffff888058200000(0000) knlGS:0000000000000000
[  114.492797] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  114.493150] CR2: 0000000000000008 CR3: 00000000013ba000 CR4: 00000000000006f0
[  114.493671] Call Trace:
[  114.493890]  <TASK>
[  114.494075]  __d_instantiate+0x24/0x1c0
[  114.494505]  d_instantiate.part.0+0x35/0x50
[  114.494754]  d_make_root+0x53/0x80
[  114.494998]  ntfs_fill_super+0x1232/0x1b50
[  114.495260]  ? put_ntfs+0x1d0/0x1d0
[  114.495499]  ? vsprintf+0x20/0x20
[  114.495723]  ? set_blocksize+0x95/0x150
[  114.495964]  get_tree_bdev+0x232/0x370
[  114.496272]  ? put_ntfs+0x1d0/0x1d0
[  114.496502]  ntfs_fs_get_tree+0x15/0x20
[  114.496859]  vfs_get_tree+0x4c/0x130
[  114.497099]  path_mount+0x654/0xfe0
[  114.497507]  ? putname+0x80/0xa0
[  114.497933]  ? finish_automount+0x2e0/0x2e0
[  114.498362]  ? putname+0x80/0xa0
[  114.498571]  ? kmem_cache_free+0x1c4/0x440
[  114.498819]  ? putname+0x80/0xa0
[  114.499069]  do_mount+0xd6/0xf0
[  114.499343]  ? path_mount+0xfe0/0xfe0
[  114.499683]  ? __kasan_check_write+0x14/0x20
[  114.500133]  __x64_sys_mount+0xca/0x110
[  114.500592]  do_syscall_64+0x3b/0x90
[  114.500930]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
[  114.501294] RIP: 0033:0x7fdc898e948a
[  114.501542] Code: 48 8b 0d 11 fa 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 008
[  114.502716] RSP: 002b:00007ffd793e58f8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
[  114.503175] RAX: ffffffffffffffda RBX: 0000564b2228f060 RCX: 00007fdc898e948a
[  114.503588] RDX: 0000564b2228f260 RSI: 0000564b2228f2e0 RDI: 0000564b22297ce0
[  114.504925] RBP: 0000000000000000 R08: 0000564b2228f280 R09: 0000000000000020
[  114.505484] R10: 00000000c0ed0000 R11: 0000000000000202 R12: 0000564b22297ce0
[  114.505823] R13: 0000564b2228f260 R14: 0000000000000000 R15: 00000000ffffffff
[  114.506562]  </TASK>
[  114.506887] Modules linked in:
[  114.507648] CR2: 0000000000000008
[  114.508884] ---[ end trace 0000000000000000 ]---
[  114.509675] RIP: 0010:d_flags_for_inode+0xe0/0x110
[  114.510140] Code: 24 f7 ff 49 83 3e 00 74 41 41 83 cd 02 66 44 89 6b 02 eb 92 48 8d 7b 20 e8 6d 24 f7 ff 4c 8b 73 20 49 8d 7e 08 e8 60 241
[  114.511762] RSP: 0018:ffff8880065e7aa8 EFLAGS: 00000296
[  114.512401] RAX: 0000000000000001 RBX: ffff888008ccd750 RCX: ffffffff84af2aea
[  114.513103] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff87abd020
[  114.513512] RBP: ffff8880065e7ac8 R08: 0000000000000001 R09: fffffbfff0f57a05
[  114.513831] R10: ffffffff87abd027 R11: fffffbfff0f57a04 R12: 0000000000000000
[  114.514757] R13: 0000000000000008 R14: 0000000000000000 R15: ffff888008ccd750
[  114.515411] FS:  00007fdc8a627e40(0000) GS:ffff888058200000(0000) knlGS:0000000000000000
[  114.515794] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  114.516208] CR2: 0000000000000008 CR3: 00000000013ba000 CR4: 00000000000006f0

Signed-off-by: Edward Lo <edward.lo@ambergroup.io>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
nathanchance pushed a commit that referenced this issue Oct 4, 2022
Although the attribute name length is checked before comparing it to
some common names (e.g., $I30), the offset isn't. This adds a sanity
check for the attribute name offset, guarantee the validity and prevent
possible out-of-bound memory accesses.

[  191.720056] BUG: unable to handle page fault for address: ffffebde00000008
[  191.721060] #PF: supervisor read access in kernel mode
[  191.721586] #PF: error_code(0x0000) - not-present page
[  191.722079] PGD 0 P4D 0
[  191.722571] Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI
[  191.723179] CPU: 0 PID: 244 Comm: mount Not tainted 6.0.0-rc4 #28
[  191.723749] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[  191.724832] RIP: 0010:kfree+0x56/0x3b0
[  191.725870] Code: 80 48 01 d8 0f 82 65 03 00 00 48 c7 c2 00 00 00 80 48 2b 15 2c 06 dd 01 48 01 d0 48 c1 e8 0c 48 c1 e0 06 48 03 05 0a 069
[  191.727375] RSP: 0018:ffff8880076f7878 EFLAGS: 00000286
[  191.727897] RAX: ffffebde00000000 RBX: 0000000000000040 RCX: ffffffff8528d5b9
[  191.728531] RDX: 0000777f80000000 RSI: ffffffff8522d49c RDI: 0000000000000040
[  191.729183] RBP: ffff8880076f78a0 R08: 0000000000000000 R09: 0000000000000000
[  191.729628] R10: ffff888008949fd8 R11: ffffed10011293fd R12: 0000000000000040
[  191.730158] R13: ffff888008949f98 R14: ffff888008949ec0 R15: ffff888008949fb0
[  191.730645] FS:  00007f3520cd7e40(0000) GS:ffff88805ba00000(0000) knlGS:0000000000000000
[  191.731328] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  191.731667] CR2: ffffebde00000008 CR3: 0000000009704000 CR4: 00000000000006f0
[  191.732568] Call Trace:
[  191.733231]  <TASK>
[  191.733860]  kvfree+0x2c/0x40
[  191.734632]  ni_clear+0x180/0x290
[  191.735085]  ntfs_evict_inode+0x45/0x70
[  191.735495]  evict+0x199/0x280
[  191.735996]  iput.part.0+0x286/0x320
[  191.736438]  iput+0x32/0x50
[  191.736811]  iget_failed+0x23/0x30
[  191.737270]  ntfs_iget5+0x337/0x1890
[  191.737629]  ? ntfs_clear_mft_tail+0x20/0x260
[  191.738201]  ? ntfs_get_block_bmap+0x70/0x70
[  191.738482]  ? ntfs_objid_init+0xf6/0x140
[  191.738779]  ? ntfs_reparse_init+0x140/0x140
[  191.739266]  ntfs_fill_super+0x121b/0x1b50
[  191.739623]  ? put_ntfs+0x1d0/0x1d0
[  191.739984]  ? asm_sysvec_apic_timer_interrupt+0x1b/0x20
[  191.740466]  ? put_ntfs+0x1d0/0x1d0
[  191.740787]  ? sb_set_blocksize+0x6a/0x80
[  191.741272]  get_tree_bdev+0x232/0x370
[  191.741829]  ? put_ntfs+0x1d0/0x1d0
[  191.742669]  ntfs_fs_get_tree+0x15/0x20
[  191.743132]  vfs_get_tree+0x4c/0x130
[  191.743457]  path_mount+0x654/0xfe0
[  191.743938]  ? putname+0x80/0xa0
[  191.744271]  ? finish_automount+0x2e0/0x2e0
[  191.744582]  ? putname+0x80/0xa0
[  191.745053]  ? kmem_cache_free+0x1c4/0x440
[  191.745403]  ? putname+0x80/0xa0
[  191.745616]  do_mount+0xd6/0xf0
[  191.745887]  ? path_mount+0xfe0/0xfe0
[  191.746287]  ? __kasan_check_write+0x14/0x20
[  191.746582]  __x64_sys_mount+0xca/0x110
[  191.746850]  do_syscall_64+0x3b/0x90
[  191.747122]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
[  191.747517] RIP: 0033:0x7f351fee948a
[  191.748332] Code: 48 8b 0d 11 fa 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 008
[  191.749341] RSP: 002b:00007ffd51cf3af8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
[  191.749960] RAX: ffffffffffffffda RBX: 000055b903733060 RCX: 00007f351fee948a
[  191.750589] RDX: 000055b903733260 RSI: 000055b9037332e0 RDI: 000055b90373bce0
[  191.751115] RBP: 0000000000000000 R08: 000055b903733280 R09: 0000000000000020
[  191.751537] R10: 00000000c0ed0000 R11: 0000000000000202 R12: 000055b90373bce0
[  191.751946] R13: 000055b903733260 R14: 0000000000000000 R15: 00000000ffffffff
[  191.752519]  </TASK>
[  191.752782] Modules linked in:
[  191.753785] CR2: ffffebde00000008
[  191.754937] ---[ end trace 0000000000000000 ]---
[  191.755429] RIP: 0010:kfree+0x56/0x3b0
[  191.755725] Code: 80 48 01 d8 0f 82 65 03 00 00 48 c7 c2 00 00 00 80 48 2b 15 2c 06 dd 01 48 01 d0 48 c1 e8 0c 48 c1 e0 06 48 03 05 0a 069
[  191.756744] RSP: 0018:ffff8880076f7878 EFLAGS: 00000286
[  191.757218] RAX: ffffebde00000000 RBX: 0000000000000040 RCX: ffffffff8528d5b9
[  191.757580] RDX: 0000777f80000000 RSI: ffffffff8522d49c RDI: 0000000000000040
[  191.758016] RBP: ffff8880076f78a0 R08: 0000000000000000 R09: 0000000000000000
[  191.758570] R10: ffff888008949fd8 R11: ffffed10011293fd R12: 0000000000000040
[  191.758957] R13: ffff888008949f98 R14: ffff888008949ec0 R15: ffff888008949fb0
[  191.759317] FS:  00007f3520cd7e40(0000) GS:ffff88805ba00000(0000) knlGS:0000000000000000
[  191.759711] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  191.760118] CR2: ffffebde00000008 CR3: 0000000009704000 CR4: 00000000000006f0

Signed-off-by: Edward Lo <edward.lo@ambergroup.io>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
nathanchance pushed a commit that referenced this issue Oct 24, 2022
Syzkaller produced the below call trace:

 BUG: KASAN: null-ptr-deref in io_msg_ring+0x3cb/0x9f0
 Write of size 8 at addr 0000000000000070 by task repro/16399

 CPU: 0 PID: 16399 Comm: repro Not tainted 6.1.0-rc1 #28
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7
 Call Trace:
  <TASK>
  dump_stack_lvl+0xcd/0x134
  ? io_msg_ring+0x3cb/0x9f0
  kasan_report+0xbc/0xf0
  ? io_msg_ring+0x3cb/0x9f0
  kasan_check_range+0x140/0x190
  io_msg_ring+0x3cb/0x9f0
  ? io_msg_ring_prep+0x300/0x300
  io_issue_sqe+0x698/0xca0
  io_submit_sqes+0x92f/0x1c30
  __do_sys_io_uring_enter+0xae4/0x24b0
....
 RIP: 0033:0x7f2eaf8f8289
 RSP: 002b:00007fff40939718 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2eaf8f8289
 RDX: 0000000000000000 RSI: 0000000000006f71 RDI: 0000000000000004
 RBP: 00007fff409397a0 R08: 0000000000000000 R09: 0000000000000039
 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004006d0
 R13: 00007fff40939880 R14: 0000000000000000 R15: 0000000000000000
  </TASK>
 Kernel panic - not syncing: panic_on_warn set ...

We don't have a NULL check on file_ptr in io_msg_send_fd() function,
so when file_ptr is NUL src_file is also NULL and get_file()
dereferences a NULL pointer and leads to above crash.

Add a NULL check to fix this issue.

Fixes: e6130eb ("io_uring: add support for passing fixed file descriptors")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Link: https://lore.kernel.org/r/20221019171218.1337614-1-harshit.m.mogalapalli@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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