CVE-2024-50182

MEDIUM EPSS 12.6%
Published Nov 8, 20241y ago · Modified Jun 17, 20262w ago
5.5 CVSS 3.1
Medium
Find Similar
Published Nov 8, 2024 1y ago
Last Modified Jun 17, 2026 2w ago

Description

In the Linux kernel, the following vulnerability has been resolved: secretmem: disable memfd_secret() if arch cannot set direct map Return -ENOSYS from memfd_secret() syscall if !can_set_direct_map(). This is the case for example on some arm64 configurations, where marking 4k PTEs in the direct map not present can only be done if the direct map is set up at 4k granularity in the first place (as ARM's break-before-make semantics do not easily allow breaking apart large/gigantic pages). More precisely, on arm64 systems with !can_set_direct_map(), set_direct_map_invalid_noflush() is a no-op, however it returns success (0) instead of an error. This means that memfd_secret will seemingly "work" (e.g. syscall succeeds, you can mmap the fd and fault in pages), but it does not actually achieve its goal of removing its memory from the direct map. Note that with this patch, memfd_secret() will start erroring on systems where can_set_direct_map() returns false (arm64 with CONFIG_RODATA_FULL_DEFAULT_ENABLED=n, CONFIG_DEBUG_PAGEALLOC=n and CONFIG_KFENCE=n), but that still seems better than the current silent failure. Since CONFIG_RODATA_FULL_DEFAULT_ENABLED defaults to 'y', most arm64 systems actually have a working memfd_secret() and aren't be affected. From going through the iterations of the original memfd_secret patch series, it seems that disabling the syscall in these scenarios was the intended behavior [1] (preferred over having set_direct_map_invalid_noflush return an error as that would result in SIGBUSes at page-fault time), however the check for it got dropped between v16 [2] and v17 [3], when secretmem moved away from CMA allocations. [1]: https://lore.kernel.org/lkml/20201124164930.GK8537@kernel.org/ [2]: https://lore.kernel.org/lkml/20210121122723.3446-11-rppt@kernel.org/#t [3]: https://lore.kernel.org/lkml/20201125092208.12544-10-rppt@kernel.org/

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
12.6% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Affected Products 6

VendorProductVersionRange
linuxlinux_kernel*≥5.14  –  <5.15.169
linuxlinux_kernel*≥5.16  –  <6.1.113
linuxlinux_kernel*≥6.2  –  <6.6.57
linuxlinux_kernel*≥6.7  –  <6.11.4
linuxlinux_kernel6.12any
linuxlinux_kernel6.12any

References 6

  • git.kernel.org https://git.kernel.org/stable/c/532b53cebe58f34ce1c0f34d866f5c0e335c53c6
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/5ea0b7af38754d2b45ead9257bca47e84662e926
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/757786abe4547eb3d9d0e8350a63bdb0f9824af2
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/7caf966390e6e4ebf42775df54e7ee1f280ce677
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/d0ae6ffa1aeb297aef89f49cfb894a83c329ebad
    Patch
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/532b53cebe58f34ce1c0f34d866f5c0e335c53c6
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/5ea0b7af38754d2b45ead9257bca47e84662e926
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/757786abe4547eb3d9d0e8350a63bdb0f9824af2
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/7caf966390e6e4ebf42775df54e7ee1f280ce677
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/d0ae6ffa1aeb297aef89f49cfb894a83c329ebad
    Patch