CVE-2021-47430
- Source
- https://nvd.nist.gov/vuln/detail/CVE-2021-47430
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-47430.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2021-47430
- Related
- Published
- 2024-05-21T15:15:28Z
- Modified
- 2024-09-18T03:17:27.790914Z
- Summary
- [none]
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
x86/entry: Clear X86FEATURESMAP when CONFIGX86SMAP=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 irqentryenterfromusermode 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:irqentryenterfromusermode ... Call Trace: ? irqentryenter ? excgeneralprotection ? asmexcgeneralprotection ? asmexcgeneral_protectio
ISENABLED(CONFIGX86_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 X86FEATURESMAP when !CONFIGX86SMAP.
Found using entry-fuzz + satrandconfig.
[ bp: Massage commit message. ]
- References
Affected packages
Debian:11 / linux
Package
- Name
- linux
- Purl
- pkg:deb/debian/linux?arch=source
Debian:12 / linux
Package
- Name
- linux
- Purl
- pkg:deb/debian/linux?arch=source
Debian:13 / linux
Package
- Name
- linux
- Purl
- pkg:deb/debian/linux?arch=source