CVE-2023-52504 | Date: (C)2024-03-05 (M)2024-06-20 |
In the Linux kernel, the following vulnerability has been resolved:
x86/alternatives: Disable KASAN in apply_alternatives()
Fei has reported that KASAN triggers during apply_alternatives() on
a 5-level paging machine:
BUG: KASAN: out-of-bounds in rcu_is_watching()
Read of size 4 at addr ff110003ee6419a0 by task swapper/0/0
...
__asan_load4()
rcu_is_watching()
trace_hardirqs_on()
text_poke_early()
apply_alternatives()
...
On machines with 5-level paging, cpu_feature_enabled(X86_FEATURE_LA57)
gets patched. It includes KASAN code, where KASAN_SHADOW_START depends on
__VIRTUAL_MASK_SHIFT, which is defined with cpu_feature_enabled().
KASAN gets confused when apply_alternatives() patches the
KASAN_SHADOW_START users. A test patch that makes KASAN_SHADOW_START
static, by replacing __VIRTUAL_MASK_SHIFT with 56, works around the issue.
Fix it for real by disabling KASAN while the kernel is patching alternatives.
[ mingo: updated the changelog ]
CVSS Score and Metrics +CVSS Score and Metrics -CVSS V3 Severity: | CVSS V2 Severity: |
CVSS Score : 6.0 | CVSS Score : |
Exploit Score: | Exploit Score: |
Impact Score: | Impact Score: |
|
CVSS V3 Metrics: | CVSS V2 Metrics: |
Attack Vector: | Access Vector: |
Attack Complexity: | Access Complexity: |
Privileges Required: | Authentication: |
User Interaction: | Confidentiality: |
Scope: | Integrity: |
Confidentiality: | Availability: |
Integrity: | |
Availability: | |
| |