# CVE-2021-47228: linux: In the Linux kernel, the following vulnerability has been resolved:  x86/ioremap: Map EFI-reserved memory as encrypte...

CVE-2021-47228 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47228, released May 21, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-47228
- Priority: Routine
- CVSS: 6.2 (medium)
- EPSS: 0.0024
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 21, 2024

## Description

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. ]

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.10.46-1 | [DEBIAN-CVE-2021-47228](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47228.md) | May 21, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.10.46-1 | [DEBIAN-CVE-2021-47228](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47228.md) | May 21, 2024 |
| Linux | linux Debian 14 | 5.10.46-1 | [DEBIAN-CVE-2021-47228](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47228.md) | May 21, 2024 |

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