CVE-2020-16120 (Medium) detected in linuxlinux-4.19.30

[mend-bolt-for-github[bot]]

CVE-2020-16120 - Medium Severity Vulnerability

Vulnerable Library - linuxlinux-4.19.30

Apache Software Foundation (ASF)

Library home page: https://mirrors.edge.kernel.org/pub/linux/kernel/v4.x/?wsslib=linux

Found in HEAD commit: 1e5b537c0e4b55545949296162ba0ff4825bff28

Found in base branch: master

Vulnerable Source Files (1)

/fs/overlayfs/readdir.c

Vulnerability Details

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.

Publish Date: 2021-02-10

URL: CVE-2020-16120

CVSS 3 Score Details (5.1)

Base Score Metrics: - Exploitability Metrics: - Attack Vector: Local - Attack Complexity: High - Privileges Required: None - User Interaction: None - Scope: Unchanged - Impact Metrics: - Confidentiality Impact: High - Integrity Impact: None - Availability Impact: None

For more information on CVSS3 Scores, click here.

Suggested Fix

Type: Upgrade version

Origin: https://www.linuxkernelcves.com/cves/CVE-2020-16120

Release Date: 2021-02-10

Fix Resolution: v5.8-rc1

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[mend-bolt-for-github[bot]]

:heavy_check_mark: This issue was automatically closed by Mend because the vulnerable library in the specific branch(es) was either marked as ignored or it is no longer part of the Mend inventory.

[mend-bolt-for-github[bot]]

:information_source: This issue was automatically re-opened by Mend because the vulnerable library in the specific branch(es) has been detected in the Mend inventory.

[mend-bolt-for-github[bot]]

:heavy_check_mark: This issue was automatically closed by Mend because the vulnerable library in the specific branch(es) was either marked as ignored or it is no longer part of the Mend inventory.

[mend-bolt-for-github[bot]]

:information_source: This issue was automatically re-opened by Mend because the vulnerable library in the specific branch(es) has been detected in the Mend inventory.

[mend-bolt-for-github[bot]]

:information_source: This issue was automatically re-opened by Mend because the vulnerable library in the specific branch(es) has been detected in the Mend inventory.

[mend-bolt-for-github[bot]]

:information_source: This issue was automatically re-opened by Mend because the vulnerable library in the specific branch(es) has been detected in the Mend inventory.