In the Linux kernel, the following vulnerability has been resolved:
x86/entry: Clear X86_FEATURE_SMAP when CONFIG_X86_SMAP=n
Commit
3c73b81a9164 ("x86/entry, selftests: Further improve user entry sanity checks")
added a warning if AC is set when in the kernel.
Commit
662a0221893a3d ("x86/entry: Fix AC assertion")
changed the warning to only fire if the CPU supports SMAP.
However, the warning can still trigger on a machine that supports SMAP but where it's disabled in the kernel config and when running the syscall_nt selftest, for example:
------------[ cut here ]------------ WARNING: CPU: 0 PID: 49 at irqentry_enter_from_user_mode CPU: 0 PID: 49 Comm: init Tainted: G T 5.15.0-rc4+ #98 e6202628ee053b4f310759978284bd8bb0ce6905 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 RIP: 0010:irqentry_enter_from_user_mode ... Call Trace: ? irqentry_enter ? exc_general_protection ? asm_exc_general_protection ? asm_exc_general_protectio
IS_ENABLED(CONFIG_X86_SMAP) could be added to the warning condition, but even this would not be enough in case SMAP is disabled at boot time with the "nosmap" parameter.
To be consistent with "nosmap" behaviour, clear X86_FEATURE_SMAP when !CONFIG_X86_SMAP.
Found using entry-fuzz + satrandconfig.
[ bp: Massage commit message. ]
CVSS Details
- CVSS 3.1 Base Score: 3.3
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade kernelUpgrade kernel-tools-develUpgrade kernel-tools-debuginfoUpgrade bpftoolUpgrade kernel-debuginfo-common-aarch64Upgrade perf-debuginfoUpgrade perfUpgrade kernel-debuginfoUpgrade kernel-develUpgrade python-perf-debuginfoUpgrade kernel-livepatch-5.10.75-79.358Upgrade bpftool-debuginfoUpgrade kernel-toolsUpgrade kernel-debuginfo-common-x86_64Upgrade python-perfUpgrade kernel-headers | May 22, 2025 | May 21, 2024 |
| Debian | — | Upgrade linux | Jul 30, 2024 | May 21, 2024 |
| Redhat_linux | — | — | Jul 9, 2025 | May 21, 2024 |
| Suse | — | Upgrade kselftests-kmp-rtUpgrade dtb-rockchipUpgrade reiserfs-kmp-rtUpgrade dtb-armUpgrade kselftests-kmp-defaultUpgrade kernel-default-optionalUpgrade kernel-azure-vdsoUpgrade reiserfs-kmp-azureUpgrade kernel-rt-livepatch-develUpgrade kernel-azure-develUpgrade kernel-devel-rtUpgrade cluster-md-kmp-defaultUpgrade kernel-default-baseUpgrade kernel-rt_debug-vdsoUpgrade dtb-renesasUpgrade kernel-syms-rtUpgrade dtb-xilinxUpgrade dtb-sprdUpgrade dtb-apmUpgrade dtb-socionextUpgrade kernel-symsUpgrade dlm-kmp-defaultUpgrade kernel-macrosUpgrade kernel-defaultUpgrade kernel-obs-qaUpgrade kernel-default-base-rebuildUpgrade kernel-debug-livepatch-develUpgrade kernel-default-extraUpgrade kernel-64kb-develUpgrade kernel-docsUpgrade dtb-mediatekUpgrade dtb-nvidiaUpgrade kernel-rt-develUpgrade kernel-rt_debugUpgrade kselftests-kmp-azureUpgrade dtb-qcomUpgrade kernel-rt_debug-livepatch-develUpgrade kernel-debugUpgrade cluster-md-kmp-azureUpgrade gfs2-kmp-defaultUpgrade dtb-broadcomUpgrade kernel-source-rtUpgrade kernel-source-vanillaUpgrade gfs2-kmp-64kbUpgrade kernel-zfcpdumpUpgrade kernel-docs-htmlUpgrade kernel-default-livepatchUpgrade kernel-rt_debug-develUpgrade kernel-64kbUpgrade kernel-default-vdsoUpgrade kernel-kvmsmallUpgrade kernel-azure-livepatch-develUpgrade ocfs2-kmp-64kbUpgrade kernel-azureUpgrade kernel-64kb-optionalUpgrade kernel-kvmsmall-livepatch-develUpgrade kernel-debug-develUpgrade kernel-kvmsmall-vdsoUpgrade gfs2-kmp-rtUpgrade dtb-alteraUpgrade gfs2-kmp-azureUpgrade dtb-allwinnerUpgrade kernel-devel-azureUpgrade kernel-obs-buildUpgrade dtb-amdUpgrade kernel-azure-optionalUpgrade ocfs2-kmp-azureUpgrade dtb-exynosUpgrade dlm-kmp-64kbUpgrade kernel-debug-vdsoUpgrade kernel-rt-vdsoUpgrade ocfs2-kmp-defaultUpgrade reiserfs-kmp-64kbUpgrade kernel-azure-extraUpgrade dtb-lgUpgrade dtb-appleUpgrade kernel-64kb-livepatch-develUpgrade dtb-amazonUpgrade kernel-source-azureUpgrade reiserfs-kmp-defaultUpgrade dtb-caviumUpgrade kernel-default-develUpgrade dtb-hisiliconUpgrade kernel-rt-extraUpgrade cluster-md-kmp-rtUpgrade kselftests-kmp-64kbUpgrade dtb-freescaleUpgrade kernel-syms-azureUpgrade dtb-marvellUpgrade kernel-sourceUpgrade kernel-rt-optionalUpgrade kernel-kvmsmall-develUpgrade kernel-rtUpgrade dlm-kmp-azureUpgrade kernel-default-livepatch-develUpgrade kernel-rt-livepatchUpgrade cluster-md-kmp-64kbUpgrade kernel-64kb-extraUpgrade dlm-kmp-rtUpgrade dtb-amlogicUpgrade ocfs2-kmp-rtUpgrade kernel-devel | Aug 9, 2024 | May 21, 2024 |
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