vulnerability

Ubuntu: (Multiple Advisories) (CVE-2023-52504): Linux kernel vulnerabilities

Severity
6
CVSS
(AV:L/AC:L/Au:S/C:C/I:N/A:C)
Published
03/02/2024
Added
07/15/2024
Modified
01/28/2025

Description

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 ]

Solution(s)

ubuntu-upgrade-linux-image-5-4-0-1038-iotubuntu-upgrade-linux-image-5-4-0-1045-xilinx-zynqmpubuntu-upgrade-linux-image-5-4-0-1073-ibmubuntu-upgrade-linux-image-5-4-0-1086-bluefieldubuntu-upgrade-linux-image-5-4-0-1093-gkeopubuntu-upgrade-linux-image-5-4-0-1110-raspiubuntu-upgrade-linux-image-5-4-0-1114-kvmubuntu-upgrade-linux-image-5-4-0-1125-oracleubuntu-upgrade-linux-image-5-4-0-1126-awsubuntu-upgrade-linux-image-5-4-0-1130-gcpubuntu-upgrade-linux-image-5-4-0-1131-azureubuntu-upgrade-linux-image-5-4-0-186-genericubuntu-upgrade-linux-image-5-4-0-186-generic-lpaeubuntu-upgrade-linux-image-5-4-0-186-lowlatencyubuntu-upgrade-linux-image-awsubuntu-upgrade-linux-image-aws-lts-20-04ubuntu-upgrade-linux-image-azureubuntu-upgrade-linux-image-azure-lts-20-04ubuntu-upgrade-linux-image-bluefieldubuntu-upgrade-linux-image-gcpubuntu-upgrade-linux-image-gcp-lts-20-04ubuntu-upgrade-linux-image-genericubuntu-upgrade-linux-image-generic-hwe-18-04ubuntu-upgrade-linux-image-generic-lpaeubuntu-upgrade-linux-image-gkeopubuntu-upgrade-linux-image-gkeop-5-4ubuntu-upgrade-linux-image-ibmubuntu-upgrade-linux-image-ibm-lts-20-04ubuntu-upgrade-linux-image-kvmubuntu-upgrade-linux-image-lowlatencyubuntu-upgrade-linux-image-lowlatency-hwe-18-04ubuntu-upgrade-linux-image-oemubuntu-upgrade-linux-image-oem-osp1ubuntu-upgrade-linux-image-oracleubuntu-upgrade-linux-image-oracle-lts-20-04ubuntu-upgrade-linux-image-raspiubuntu-upgrade-linux-image-raspi-hwe-18-04ubuntu-upgrade-linux-image-raspi2ubuntu-upgrade-linux-image-snapdragon-hwe-18-04ubuntu-upgrade-linux-image-virtualubuntu-upgrade-linux-image-virtual-hwe-18-04ubuntu-upgrade-linux-image-xilinx-zynqmp
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