CVE-2022-50211

In the Linux kernel, the following vulnerability has been resolved:

md-raid10: fix KASAN warning

Theres a KASAN warning in raid10_remove_disk when running the lvm test lvconvert-raid-reshape.sh. We fix this warning by verifying that the value number is valid.

BUG: KASAN: slab-out-of-bounds in raid10_remove_disk+0x61/0x2a0 [raid10] Read of size 8 at addr ffff889108f3d300 by task mdX_raid10/124682

CPU: 3 PID: 124682 Comm: mdX_raid10 Not tainted 5.19.0-rc6 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Call Trace: dump_stack_lvl+0x34/0x44 print_report.cold+0x45/0x57a ? __lock_text_start+0x18/0x18 ? raid10_remove_disk+0x61/0x2a0 [raid10] kasan_report+0xa8/0xe0 ? raid10_remove_disk+0x61/0x2a0 [raid10] raid10_remove_disk+0x61/0x2a0 [raid10] Buffer I/O error on dev dm-76, logical block 15344, async page read ? __mutex_unlock_slowpath.constprop.0+0x1e0/0x1e0 remove_and_add_spares+0x367/0x8a0 [md_mod] ? super_written+0x1c0/0x1c0 [md_mod] ? mutex_trylock+0xac/0x120 ? _raw_spin_lock+0x72/0xc0 ? _raw_spin_lock_bh+0xc0/0xc0 md_check_recovery+0x848/0x960 [md_mod] raid10d+0xcf/0x3360 [raid10] ? sched_clock_cpu+0x185/0x1a0 ? rb_erase+0x4d4/0x620 ? var_wake_function+0xe0/0xe0 ? psi_group_change+0x411/0x500 ? preempt_count_sub+0xf/0xc0 ? _raw_spin_lock_irqsave+0x78/0xc0 ? __lock_text_start+0x18/0x18 ? raid10_sync_request+0x36c0/0x36c0 [raid10] ? preempt_count_sub+0xf/0xc0 ? _raw_spin_unlock_irqrestore+0x19/0x40 ? del_timer_sync+0xa9/0x100 ? try_to_del_timer_sync+0xc0/0xc0 ? _raw_spin_lock_irqsave+0x78/0xc0 ? __lock_text_start+0x18/0x18 ? _raw_spin_unlock_irq+0x11/0x24 ? __list_del_entry_valid+0x68/0xa0 ? finish_wait+0xa3/0x100 md_thread+0x161/0x260 [md_mod] ? unregister_md_personality+0xa0/0xa0 [md_mod] ? _raw_spin_lock_irqsave+0x78/0xc0 ? prepare_to_wait_event+0x2c0/0x2c0 ? unregister_md_personality+0xa0/0xa0 [md_mod] kthread+0x148/0x180 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30

Allocated by task 124495: kasan_save_stack+0x1e/0x40 __kasan_kmalloc+0x80/0xa0 setup_conf+0x140/0x5c0 [raid10] raid10_run+0x4cd/0x740 [raid10] md_run+0x6f9/0x1300 [md_mod] raid_ctr+0x2531/0x4ac0 [dm_raid] dm_table_add_target+0x2b0/0x620 [dm_mod] table_load+0x1c8/0x400 [dm_mod] ctl_ioctl+0x29e/0x560 [dm_mod] dm_compat_ctl_ioctl+0x7/0x20 [dm_mod] __do_compat_sys_ioctl+0xfa/0x160 do_syscall_64+0x90/0xc0 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Last potentially related work creation: kasan_save_stack+0x1e/0x40 __kasan_record_aux_stack+0x9e/0xc0 kvfree_call_rcu+0x84/0x480 timerfd_release+0x82/0x140 L __fput+0xfa/0x400 task_work_run+0x80/0xc0 exit_to_user_mode_prepare+0x155/0x160 syscall_exit_to_user_mode+0x12/0x40 do_syscall_64+0x42/0xc0 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Second to last potentially related work creation: kasan_save_stack+0x1e/0x40 __kasan_record_aux_stack+0x9e/0xc0 kvfree_call_rcu+0x84/0x480 timerfd_release+0x82/0x140 __fput+0xfa/0x400 task_work_run+0x80/0xc0 exit_to_user_mode_prepare+0x155/0x160 syscall_exit_to_user_mode+0x12/0x40 do_syscall_64+0x42/0xc0 entry_SYSCALL_64_after_hwframe+0x46/0xb0

The buggy address belongs to the object at ffff889108f3d200 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 0 bytes to the right of 256-byte region [ffff889108f3d200, ffff889108f3d300)

The buggy address belongs to the physical page: page:000000007ef2a34c refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1108f3c head:000000007ef2a34c order:2 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=2) raw: 4000000000010200 0000000000000000 dead000000000001 ffff889100042b40 raw: 0000000000000000 0000000080200020 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected

Memory state around the buggy address: ffff889108f3d200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff889108f3d280: 00 00 —truncated—

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
• To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/540.html

References

• https://git.kernel.org/stable/c/0f4d18cbea4a6e37a05fd8ee2887439f85211110
• https://git.kernel.org/stable/c/5f57843565131bb782388f9d993f9ee8f453dee1
• https://git.kernel.org/stable/c/5fd4ffa2372a41361d2bdd27ea5730e4e673240c
• https://git.kernel.org/stable/c/75fbd370a2cec9e92f48285bd90735ed0c837f52
• https://git.kernel.org/stable/c/7a6ccc8fa192fd357c2d5d4c6ce67c834a179e23
• https://git.kernel.org/stable/c/bcbdc26a44aba488d2f7122f2d66801bccb74733
• https://git.kernel.org/stable/c/bf30b9ba09b0ac2a10f04dce2b0835ec4d178aa6
• https://git.kernel.org/stable/c/ce839b9331c11780470f3d727b6fe3c2794a4620
• https://git.kernel.org/stable/c/d17f744e883b2f8d13cca252d71cfe8ace346f7d