CVE-2024-56761
Jan. 9, 2025, 4:16 p.m.
5.5
Medium
Description
In the Linux kernel, the following vulnerability has been resolved:
x86/fred: Clear WFE in missing-ENDBRANCH #CPs
An indirect branch instruction sets the CPU indirect branch tracker
(IBT) into WAIT_FOR_ENDBRANCH (WFE) state and WFE stays asserted
across the instruction boundary. When the decoder finds an
inappropriate instruction while WFE is set ENDBR, the CPU raises a #CP
fault.
For the "kernel IBT no ENDBR" selftest where #CPs are deliberately
triggered, the WFE state of the interrupted context needs to be
cleared to let execution continue. Otherwise when the CPU resumes
from the instruction that just caused the previous #CP, another
missing-ENDBRANCH #CP is raised and the CPU enters a dead loop.
This is not a problem with IDT because it doesn't preserve WFE and
IRET doesn't set WFE. But FRED provides space on the entry stack
(in an expanded CS area) to save and restore the WFE state, thus the
WFE state is no longer clobbered, so software must clear it.
Clear WFE to avoid dead looping in ibt_clear_fred_wfe() and the
!ibt_fatal code path when execution is allowed to continue.
Clobbering WFE in any other circumstance is a security-relevant bug.
[ dhansen: changelog rewording ]
Product(s) Impacted
| Vendor | Product | Versions |
|---|---|---|
| Linux |
|
|
Weaknesses
*CPE(s)
| Type | Vendor | Product | Version | Update | Edition | Language | Software Edition | Target Software | Target Hardware | Other Information |
|---|---|---|---|---|---|---|---|---|---|---|
| o | linux | linux_kernel | / | / | / | / | / | / | / | / |
| o | linux | linux_kernel | 6.13 | rc1 | / | / | / | / | / | / |
| o | linux | linux_kernel | 6.13 | rc2 | / | / | / | / | / | / |
| o | linux | linux_kernel | 6.13 | rc3 | / | / | / | / | / | / |
| o | linux | linux_kernel | 6.13 | rc4 | / | / | / | / | / | / |
Tags
CVSS Score
CVSS Data
- Attack Vector: LOCAL
- Attack Complexity: LOW
- Privileges Required: LOW
- Scope: UNCHANGED
- Confidentiality Impact: NONE
- Integrity Impact: NONE
- Availability Impact: HIGH
View Vector String
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Date
- Published: Jan. 6, 2025, 5:15 p.m.
- Last Modified: Jan. 9, 2025, 4:16 p.m.
Status : Modified
CVE has been recently published to the CVE List and has been received by the NVD.
More infoSource
416baaa9-dc9f-4396-8d5f-8c081fb06d67
*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.