[<prev] [next>] [day] [month] [year] [list]
Date: Sat, 2 Apr 2022 16:45:07 +0800 (GMT+08:00)
From: 周多明 <duoming@....edu.cn>
To: oss-security@...ts.openwall.com
Subject: CVE-2022-1199 kernel: Null pointer dereference and use-after-free
in ax25_release()
Hello there,
There are null-ptr-deref vulnerability and use-after-free vulnerabilities in net/ax25/af_ax25.c
of linux that allow attacker to crash linux kernel by simulating ax25 device from user-space.
=*=*=*=*=*=*=*=*= Bug Details =*=*=*=*=*=*=*=*=
The null-ptr-deref vulnerability is caused by "ax25->sk = NULL" in ax25_release().
The dereference sites include "bh_lock_sock(ax25->sk)" and "bh_unlock_sock(ax25->sk)"
in ax25_disconnect(), "lock_sock(s->sk)" and "release_sock(s->sk)" in ax25_kill_by_device().
The NPD bug related with bh_lock_sock(ax25->sk) is shown below:
ax25_kill_by_device() | ax25_release()
ax25_disconnect() | ax25_destroy_socket()
... |
if(ax25->sk != NULL) | ...
... | ax25->sk = NULL;
bh_lock_sock(ax25->sk); //(1) | ...
... |
bh_unlock_sock(ax25->sk); //(2)|
The NPD bug related with lock_sock(s->sk) is shown below:
ax25_kill_by_device() | ax25_release()
| ax25_destroy_socket()
| ax25_cb_del()
... | ...
| ax25->sk=NULL;
lock_sock(s->sk); //(1) |
s->ax25_dev = NULL; | ...
release_sock(s->sk); //(2) |
... |
The use-after-free vulnerability is caused by "sock_put(sk)" in ax25_release(). The dereference
sites include "lock_sock(s->sk)" and "release_sock(s->sk)" in ax25_kill_by_device().
ax25_kill_by_device() | ax25_release()
| ax25_destroy_socket()
... | ...
| sock_put(sk); //FREE
lock_sock(s->sk); //(1) |
s->ax25_dev = NULL; | ...
release_sock(s->sk); //(2) |
... |
=*=*=*=*=*=*=*=*= Bug Effects =*=*=*=*=*=*=*=*=
We can successfully trigger the vulnerabilities to crash the linux kernel.
The NPD bug related with bh_lock_sock() is shown below.
[ 178.776298] BUG: kernel NULL pointer dereference, address: 0000000000000088
[ 178.777929] RIP: 0010:_raw_spin_lock+0x7e/0xd0
[ 178.777929] Code: be 04 00 00 00 c7 44 24 20 00 00 00 00 e8 2a 29 e8 fe be 04 00 00 00 48 8d 7c 24 20 e8 1b 29 e8 fe ba 01 00 00 00 8b 44 24 20 <f0> 0f b1 55 00 75 29 48 b8 00 00 00 00
[ 178.777929] RSP: 0018:ffff888007dcfa48 EFLAGS: 00000297
[ 178.777929] RAX: 0000000000000000 RBX: 1ffff11000fb9f49 RCX: ffffffff82482855
[ 178.777929] RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff888007dcfa68
[ 178.777929] RBP: 0000000000000088 R08: 0000000000000001 R09: 0000000000000003
[ 178.777929] R10: ffffed1000fb9f4d R11: 0000000000000001 R12: 0000000000000065
[ 178.777929] R13: ffff888009f99800 R14: ffff888009f99860 R15: ffff888009f99800
[ 178.777929] FS: 00007f9651ce3700(0000) GS:ffff88806d480000(0000) knlGS:0000000000000000
[ 178.777929] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 178.777929] CR2: 0000000000000088 CR3: 0000000009876000 CR4: 00000000000006e0
[ 178.777929] Call Trace:
[ 178.777929] ? _raw_read_lock_irq+0x30/0x30
[ 178.777929] ? _raw_spin_unlock_bh+0x9/0x20
[ 178.777929] ? ax25_link_failed+0x40/0x60
[ 178.777929] ax25_disconnect+0xf6/0x220
[ 178.777929] ax25_device_event+0x187/0x250
[ 178.777929] raw_notifier_call_chain+0x5e/0x70
[ 178.777929] dev_close_many+0x17d/0x230
[ 178.777929] ? __dev_close_many+0x1c0/0x1c0
[ 178.777929] rollback_registered_many+0x1f1/0x950
[ 178.777929] ? _raw_write_lock_irqsave+0xd0/0xd0
[ 178.777929] ? dev_alloc_name+0xd0/0xd0
[ 178.777929] ? ldsem_down_read+0x410/0x410
[ 178.777929] unregister_netdevice_queue+0x133/0x200
[ 178.777929] ? unregister_netdevice_many+0x20/0x20
[ 178.777929] ? sixpack_close+0xf8/0x130
[ 178.777929] unregister_netdev+0x13/0x20
[ 178.777929] tty_ldisc_hangup+0x1ab/0x2d0
[ 178.777929] __tty_hangup.part.0+0x306/0x510
[ 178.777929] tty_release+0x200/0x670
[ 178.777929] __fput+0x104/0x3b0
[ 178.777929] task_work_run+0x8f/0xd0
[ 178.777929] exit_to_user_mode_prepare+0x114/0x120
[ 178.777929] syscall_exit_to_user_mode+0x1d/0x40
[ 178.777929] entry_SYSCALL_64_after_hwframe+0x44/0xa9
The NPD bug related with lock_sock() is shown below.
[ 727.493561] BUG: kernel NULL pointer dereference, address: 0000000000000088
[ 727.493561] RIP: 0010:_raw_spin_lock_bh+0x89/0xd0
[ 727.493561] Code: be 04 00 00 00 c7 44 24 20 00 00 00 00 e8 5f c6 f1 fd be 04 00 00 00 48 8d 7c 24 20 e8 50 c6 f1 fd ba 01 00 00 00 8b 44 24 20 <f0> 0f b1 55 00 75 29 48 b8 00 00 00 00
[ 727.493561] RSP: 0018:ffff88801569f9c0 EFLAGS: 00000297
[ 727.493561] RAX: 0000000000000000 RBX: 1ffff11002ad3f38 RCX: ffffffff8366d960
[ 727.493561] RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff88801569f9e0
[ 727.493561] RBP: 0000000000000088 R08: 0000000000000001 R09: 0000000000000003
[ 727.493561] R10: ffffed1002ad3f3c R11: 0000000000000001 R12: 0000000000000088
[ 727.493561] R13: ffff888016166700 R14: ffff888014a57dc8 R15: dffffc0000000000
[ 727.493561] FS: 00007f5cab712700(0000) GS:ffff88806d200000(0000) knlGS:0000000000000000
[ 727.493561] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 727.493561] CR2: 0000000000000088 CR3: 000000000a336000 CR4: 00000000000006f0
[ 727.493561] Call Trace:
[ 727.493561] ? _raw_spin_lock+0xd0/0xd0
[ 727.493561] release_sock+0x16/0x170
[ 727.493561] ax25_device_event+0x1a3/0x270
[ 727.493561] ? nr_device_event+0xf2/0x140
[ 727.493561] raw_notifier_call_chain+0x8d/0xd0
[ 727.493561] dev_close_many+0x227/0x400
[ 727.493561] ? __dev_close_many+0x290/0x290
[ 727.493561] ? finish_task_switch.isra.0+0x205/0x620
[ 727.493561] ? __switch_to+0x572/0xe50
[ 727.493561] rollback_registered_many+0x2e1/0x1130
[ 727.493561] ? dev_alloc_name+0xf0/0xf0
[ 727.493561] ? ldsem_down_read+0x650/0x650
[ 727.493561] unregister_netdevice_queue+0x1d7/0x3e0
[ 727.493561] ? unregister_netdevice_many+0x50/0x50
[ 727.493561] ? _raw_write_lock_bh+0xd0/0xd0
[ 727.493561] ? down_write_killable+0x120/0x120
[ 727.493561] unregister_netdev+0x13/0x20
[ 727.493561] mkiss_close+0x116/0x1f0
[ 727.493561] tty_ldisc_hangup+0x227/0x5f0
[ 727.493561] ? fasync_remove_entry+0x28/0x220
[ 727.493561] __tty_hangup.part.0+0x41c/0x910
[ 727.493561] tty_release+0x3a8/0xcc0
[ 727.493561] __fput+0x1e2/0x840
[ 727.493561] task_work_run+0xe8/0x180
[ 727.493561] exit_to_user_mode_prepare+0x114/0x120
[ 727.493561] syscall_exit_to_user_mode+0x1d/0x40
[ 727.493561] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 727.493561] RIP: 0033:0x7f6d2c9d4beb
[ 727.493561] Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 33 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 2f 44 89 c7 89 44
[ 727.493561] RSP: 002b:00007f5cab711ec0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
[ 727.493561] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f6d2c9d4beb
[ 727.493561] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
[ 727.493561] RBP: 00007f5cab711f00 R08: 0000000000000000 R09: 00007f5cab712700
[ 727.493561] R10: 0000000000000000 R11: 0000000000000293 R12: 00007ffee89407be
[ 727.493561] R13: 00007ffee89407bf R14: 00007f5cab711fc0 R15: 00007f5cab712700
The UAF bug related with lock_sock() is shown below.
[ 208.472360] BUG: KASAN: use-after-free in _raw_spin_lock_bh+0x71/0xd0
[ 208.472465] Write of size 4 at addr ffff88800a0e8088 by task ax25_clo_bin/1271
[ 208.472465] Call Trace:
[ 208.472465] dump_stack+0x7d/0xa3
[ 208.472465] print_address_description.constprop.0+0x18/0x130
[ 208.472465] ? _raw_spin_lock_bh+0x71/0xd0
[ 208.472465] ? _raw_spin_lock_bh+0x71/0xd0
[ 208.472465] kasan_report.cold+0x7f/0x10e
[ 208.472465] ? _raw_spin_lock_bh+0x71/0xd0
[ 208.472465] check_memory_region+0xf9/0x1e0
[ 208.472465] _raw_spin_lock_bh+0x71/0xd0
[ 208.472465] ? _raw_spin_lock+0xd0/0xd0
[ 208.472465] ? schedule+0x8e/0x120
[ 208.472465] __lock_sock+0xd9/0x140
[ 208.472465] ? sock_omalloc+0xc0/0xc0
[ 208.472465] ? _raw_spin_lock+0xd0/0xd0
[ 208.472465] ? wait_woken+0x110/0x110
[ 208.472465] ? _raw_spin_lock+0xd0/0xd0
[ 208.472465] ? _raw_spin_lock_bh+0x80/0xd0
[ 208.472465] ? _raw_spin_lock+0xd0/0xd0
[ 208.472465] lock_sock_nested+0x72/0x80
[ 208.472465] ax25_device_event+0xef/0x160
[ 208.472465] raw_notifier_call_chain+0x5e/0x70
[ 208.472465] dev_close_many+0x17d/0x230
[ 208.472465] ? __dev_close_many+0x1c0/0x1c0
[ 208.472465] ? __schedule+0x494/0xc30
[ 208.472465] rollback_registered_many+0x1f1/0x950
[ 208.472465] ? clockevents_program_event+0xd3/0x130
[ 208.472465] ? dev_alloc_name+0xd0/0xd0
[ 208.472465] ? ldsem_down_read+0x410/0x410
[ 208.472465] unregister_netdevice_queue+0x133/0x200
[ 208.472465] ? unregister_netdevice_many+0x20/0x20
[ 208.472465] ? _raw_write_lock_bh+0xd0/0xd0
[ 208.472465] unregister_netdev+0x13/0x20
[ 208.472465] mkiss_close+0xc4/0x120
[ 208.472465] tty_ldisc_hangup+0x1ab/0x2d0
[ 208.472465] __tty_hangup.part.0+0x306/0x510
[ 208.472465] tty_release+0x200/0x670
[ 208.472465] __fput+0x104/0x3b0
[ 208.472465] task_work_run+0x8f/0xd0
[ 208.472465] exit_to_user_mode_prepare+0x114/0x120
[ 208.472465] syscall_exit_to_user_mode+0x1d/0x40
[ 208.472465] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 208.472465] RIP: 0033:0x7f7900bb1beb
[ 208.472465] Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 33 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 2f 44 89 c7 89 44 24 0c e8 71 fc ff ff 8b 44
[ 208.472465] RSP: 002b:00007f78ff9c8ec0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
[ 208.472465] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f7900bb1beb
[ 208.472465] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
[ 208.472465] RBP: 00007f78ff9c8f00 R08: 0000000000000000 R09: 00007f78ff9c9700
[ 208.472465] R10: 0000000000000000 R11: 0000000000000293 R12: 00007ffd364d6b9e
[ 208.472465] R13: 00007ffd364d6b9f R14: 00007f78ff9c8fc0 R15: 00007f78ff9c9700
=*=*=*=*=*=*=*=*= Bug Fix =*=*=*=*=*=*=*=*=
The patch that have been applied to mainline Linux kernel is shown below.
https://github.com/torvalds/linux/commit/4e0f718daf97d47cf7dec122da1be970f145c809
https://github.com/torvalds/linux/commit/7ec02f5ac8a5be5a3f20611731243dc5e1d9ba10
https://github.com/torvalds/linux/commit/71171ac8eb34ce7fe6b3267dce27c313ab3cb3ac
=*=*=*=*=*=*=*=*= Timeline =*=*=*=*=*=*=*=*=
2022-01-28: commit 4e0f718daf97 accepted to mainline kernel
2022-02-09: commit 7ec02f5ac8a5 accepted to mainline kernel
2022-03-09: commit 71171ac8eb34 accepted to mainline kernel
2022-04-01: CVE-2022-1199 is assigned
=*=*=*=*=*=*=*=*= Credit =*=*=*=*=*=*=*=*=
Duoming Zhou <duoming@....edu.cn>
Best Regards,
Duoming Zhou
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
