ghsa-w5h9-gvgr-jhpg
Vulnerability from github
Published
2024-05-21 15:31
Modified
2024-10-31 18:31
Severity ?
6.2 (Medium) - CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Details

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. ]

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{
  "affected": [],
  "aliases": [
    "CVE-2021-47228"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-05-21T15:15:12Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/ioremap: Map EFI-reserved memory as encrypted for SEV\n\nSome drivers require memory that is marked as EFI boot services\ndata. In order for this memory to not be re-used by the kernel\nafter ExitBootServices(), efi_mem_reserve() is used to preserve it\nby inserting a new EFI memory descriptor and marking it with the\nEFI_MEMORY_RUNTIME attribute.\n\nUnder SEV, memory marked with the EFI_MEMORY_RUNTIME attribute needs to\nbe mapped encrypted by Linux, otherwise the kernel might crash at boot\nlike below:\n\n  EFI Variables Facility v0.08 2004-May-17\n  general protection fault, probably for non-canonical address 0x3597688770a868b2: 0000 [#1] SMP NOPTI\n  CPU: 13 PID: 1 Comm: swapper/0 Not tainted 5.12.4-2-default #1 openSUSE Tumbleweed\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015\n  RIP: 0010:efi_mokvar_entry_next\n  [...]\n  Call Trace:\n   efi_mokvar_sysfs_init\n   ? efi_mokvar_table_init\n   do_one_initcall\n   ? __kmalloc\n   kernel_init_freeable\n   ? rest_init\n   kernel_init\n   ret_from_fork\n\nExpand the __ioremap_check_other() function to additionally check for\nthis other type of boot data reserved at runtime and indicate that it\nshould be mapped encrypted for an SEV guest.\n\n [ bp: Massage commit message. ]",
  "id": "GHSA-w5h9-gvgr-jhpg",
  "modified": "2024-10-31T18:31:16Z",
  "published": "2024-05-21T15:31:39Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47228"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/208bb686e7fa7fff16e8fa78ff0db34aa9acdbd7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8d651ee9c71bb12fc0c8eb2786b66cbe5aa3e43b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b7a05aba39f733ec337c5b952e112dd2dc4fc404"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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