CVE-2024-50182 Affecting kernel-uek-modules-extra package, versions <0:5.15.0-303.171.5.2.el8uek


Severity

Recommended
high

Based on Oracle Linux security rating.

Threat Intelligence

EPSS
0.05% (18th percentile)

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  • Snyk IDSNYK-ORACLE8-KERNELUEKMODULESEXTRA-8539403
  • published20 Dec 2024
  • disclosed8 Nov 2024

Introduced: 8 Nov 2024

CVE-2024-50182  (opens in a new tab)

How to fix?

Upgrade Oracle:8 kernel-uek-modules-extra to version 0:5.15.0-303.171.5.2.el8uek or higher.
This issue was patched in ELSA-2024-12887.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-uek-modules-extra package and not the kernel-uek-modules-extra package as distributed by Oracle. See How to fix? for Oracle:8 relevant fixed versions and status.

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.

CVSS Scores

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