In the Linux kernel, the following vulnerability has been resolved: exit: prevent preemption of oopsing TASK_DEAD task When an already-exiting task oopses, make_task_dead() currently calls do_task_dead() with preemption enabled. That is forbidden: do_task_dead() calls __schedule(), which has a comment saying "WARNING: must be called with preemption disabled!". If an oopsing task is preempted in do_task_dead(), between becoming TASK_DEAD and entering the scheduler explicitly, bad things happen: finish_task_switch() assumes that once the scheduler has switched away from a TASK_DEAD task, the task can never run again and its stack is no longer needed; but that assumption apparently doesn't hold if the dead task was preempted (the SM_PREEMPT case). This means that the scheduler ends up repeatedly dropping references on the dead task's stack, which can lead to use-after-free or double-free of the entire task stack; in other words, two tasks can end up running on the same stack, resulting in various kinds of memory corruption. (This does not just affect "recursively oopsing" tasks; it is enough to oops once during task exit, for example in a file_operations::release handler)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
| Attack Vector | LOCAL |
|---|---|
| Attack Complexity | LOW |
| Privileges Required | LOW |
| User Interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality Impact | HIGH |
| Integrity Impact | HIGH |
| Availability Impact | HIGH |
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Type: Secondary
Exploitability Score: 1.8
Impact Score: 5.9
| Source | Type | Description |
|---|---|---|
| [email protected] | Primary |
en
CWE-787
|
| Vendor | Product | Version | Update | Type |
|---|---|---|---|---|
| linux | linux_kernel | * | <built-in method update of dict object at 0x7d23549fec80> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x7d2364d6a800> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x7d24245b8a40> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x7d23a52f6140> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x7d236440f5c0> | Operating System |
| linux | linux_kernel | 7.1 | <built-in method update of dict object at 0x7d236440c5c0> | Operating System |
| linux | linux_kernel | 7.1 | <built-in method update of dict object at 0x7d242450be00> | Operating System |
| linux | linux_kernel | 7.1 | <built-in method update of dict object at 0x7d2364d6adc0> | Operating System |
| Vulnerable | CPE |
|---|---|
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* |