CVE-2021-47228: x86/ioremap: Map EFI-reserved memory as encrypted for SEV
First published: Tue May 21 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: x86/ioremap: Map EFI-reserved memory as encrypted for SEV Some drivers require memory that is marked as EFI boot services data. In order for this memory to not be re-used by the kernel after ExitBootServices(), efi_mem_reserve() is used to preserve it by inserting a new EFI memory descriptor and marking it with the EFI_MEMORY_RUNTIME attribute. Under SEV, memory marked with the EFI_MEMORY_RUNTIME attribute needs to be mapped encrypted by Linux, otherwise the kernel might crash at boot like below: EFI Variables Facility v0.08 2004-May-17 general protection fault, probably for non-canonical address 0x3597688770a868b2: 0000 [#1] SMP NOPTI CPU: 13 PID: 1 Comm: swapper/0 Not tainted 5.12.4-2-default #1 openSUSE Tumbleweed Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:efi_mokvar_entry_next [...] Call Trace: efi_mokvar_sysfs_init ? efi_mokvar_table_init do_one_initcall ? __kmalloc kernel_init_freeable ? rest_init kernel_init ret_from_fork Expand the __ioremap_check_other() function to additionally check for this other type of boot data reserved at runtime and indicate that it should be mapped encrypted for an SEV guest. [ bp: Massage commit message. ]
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Red Hat Kernel-devel | =5.12.4 | |
| Linux Kernel | >=5.10<5.10.46 | |
| Linux Kernel | >=5.11<5.12.13 | |
| Linux Kernel | =5.13-rc1 | |
| Linux Kernel | =5.13-rc2 | |
| Linux Kernel | =5.13-rc3 | |
| Linux Kernel | =5.13-rc4 | |
| Linux Kernel | =5.13-rc5 | |
| Linux Kernel | =5.13-rc6 |
Never miss a vulnerability like this again
Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.
Reference Links
Frequently Asked Questions
What is the severity of CVE-2021-47228?
CVE-2021-47228 has been classified as a moderate severity vulnerability in the Linux kernel.
How do I fix CVE-2021-47228?
To fix CVE-2021-47228, you should upgrade your Linux kernel to version 5.12.5 or later where the vulnerability has been addressed.
What are the potential impacts of CVE-2021-47228?
CVE-2021-47228 can lead to unauthorized memory access and potential exploitation due to improper handling of EFI-reserved memory.
Which versions of Linux kernel are affected by CVE-2021-47228?
CVE-2021-47228 affects the Linux kernel version 5.12.4 and earlier releases.
Is CVE-2021-47228 a remote or local exploit?
CVE-2021-47228 is considered a local exploit that can be utilized by a user with local access to the system.
- agent/references
- agent/title
- agent/type
- agent/description
- agent/first-publish-date
- agent/author
- agent/severity
- agent/event
- collector/mitre-cve
- source/MITRE
- agent/source
- agent/guess-ai
- agent/software-canonical-lookup
- agent/software-canonical-lookup-request
- collector/nvd-api
- source/NVD
- agent/remedy
- agent/last-modified-date
- agent/softwarecombine
- agent/tags
- vendor/linux
- canonical/red hat kernel-devel
- canonical/linux kernel
- version/linux kernel/5.10
- version/linux kernel/5.11
- version/linux kernel/5.13-rc1
- version/linux kernel/5.13-rc2
- version/linux kernel/5.13-rc3
- version/linux kernel/5.13-rc4
- version/linux kernel/5.13-rc5
- version/linux kernel/5.13-rc6