CVE-2024-26756
Description
From CVE.org
In the Linux kernel, the following vulnerability has been resolved: md: Don't register sync_thread for reshape directly Currently, if reshape is interrupted, then reassemble the array will register sync_thread directly from pers->run(), in this case 'MD_RECOVERY_RUNNING' is set directly, however, there is no guarantee that md_do_sync() will be executed, hence stop_sync_thread() will hang because 'MD_RECOVERY_RUNNING' can't be cleared. Last patch make sure that md_do_sync() will set MD_RECOVERY_DONE, however, following hang can still be triggered by dm-raid test shell/lvconvert-raid-reshape.sh occasionally: [root@fedora ~]# cat /proc/1982/stack [<0>] stop_sync_thread+0x1ab/0x270 [md_mod] [<0>] md_frozen_sync_thread+0x5c/0xa0 [md_mod] [<0>] raid_presuspend+0x1e/0x70 [dm_raid] [<0>] dm_table_presuspend_targets+0x40/0xb0 [dm_mod] [<0>] __dm_destroy+0x2a5/0x310 [dm_mod] [<0>] dm_destroy+0x16/0x30 [dm_mod] [<0>] dev_remove+0x165/0x290 [dm_mod] [<0>] ctl_ioctl+0x4bb/0x7b0 [dm_mod] [<0>] dm_ctl_ioctl+0x11/0x20 [dm_mod] [<0>] vfs_ioctl+0x21/0x60 [<0>] __x64_sys_ioctl+0xb9/0xe0 [<0>] do_syscall_64+0xc6/0x230 [<0>] entry_SYSCALL_64_after_hwframe+0x6c/0x74 Meanwhile mddev->recovery is: MD_RECOVERY_RUNNING | MD_RECOVERY_INTR | MD_RECOVERY_RESHAPE | MD_RECOVERY_FROZEN Fix this problem by remove the code to register sync_thread directly from raid10 and raid5. And let md_check_recovery() to register sync_thread.
Statement
For the Red Hat Enterprise Linux 9 (all versions) the bug already fixed. For older Red Hat Enterprise Linux 8 bug exists, but no plan to fix it, because low severity bug: only system administrator can trigger it (with some commands for Raid control that is MD), and if Raid not being used, then impossible to trigger it. Also triggering the bug leads to "hang" (froze) only, so impossible to use it for attack like privileges escalation.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.4 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | High | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
An attacker could provide unexpected values and cause a program crash or arbitrary control of resource allocation, leading to excessive consumption of resources such as memory and CPU.
Confidentiality
Technical Impact: Read Memory; Read Files or Directories
An attacker could read confidential data if they are able to control resource references.
Integrity,Confidentiality,Availability
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
An attacker could use malicious input to modify data or possibly alter control flow in unexpected ways, including arbitrary command execution.
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