CVE-2020-16120 Affecting kernel-docs package, versions <5.3.18-24.34.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.05% (20th percentile)

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  • Snyk IDSNYK-SLES152-KERNELDOCS-2699097
  • published14 Apr 2022
  • disclosed3 Nov 2020

Introduced: 3 Nov 2020

CVE-2020-16120  (opens in a new tab)

How to fix?

Upgrade SLES:15.2 kernel-docs to version 5.3.18-24.34.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-docs package and not the kernel-docs package as distributed by SLES. See How to fix? for SLES:15.2 relevant fixed versions and status.

Overlayfs did not properly perform permission checking when copying up files in an overlayfs and could be exploited from within a user namespace, if, for example, unprivileged user namespaces were allowed. It was possible to have a file not readable by an unprivileged user to be copied to a mountpoint controlled by the user, like a removable device. This was introduced in kernel version 4.19 by commit d1d04ef ("ovl: stack file ops"). This was fixed in kernel version 5.8 by commits 56230d9 ("ovl: verify permissions in ovl_path_open()"), 48bd024 ("ovl: switch to mounter creds in readdir") and 05acefb ("ovl: check permission to open real file"). Additionally, commits 130fdbc ("ovl: pass correct flags for opening real directory") and 292f902 ("ovl: call secutiry hook in ovl_real_ioctl()") in kernel 5.8 might also be desired or necessary. These additional commits introduced a regression in overlay mounts within user namespaces which prevented access to files with ownership outside of the user namespace. This regression was mitigated by subsequent commit b6650da ("ovl: do not fail because of O_NOATIMEi") in kernel 5.11.

CVSS Scores

version 3.1