SB2019110642 - Multiple vulnerabilities in Linux kernel

Description

This security bulletin contains information about 2 vulnerabilities.

1) Memory leak (CVE-ID: CVE-2019-18786)

CWE-ID: CWE-401 - Missing release of memory after effective lifetime

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to gain access to sensitive information.

The vulnerability exists due memory leak within the rcar_drif_g_fmt_sdr_cap() function in drivers/media/platform/rcar_drif.c in Linux kernel. A local user can disclose uninitialized memory.

2) Race condition (CVE-ID: CVE-2019-18683)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a race condition, caused by wrong mutex locking in vivid_stop_generating_vid_cap(), vivid_stop_generating_vid_out(), sdr_cap_stop_streaming(), and the corresponding kthreads. A local user can exploit the race and gain unauthorized access to sensitive information and escalate privileges on the system.

Successful exploitation of the vulnerability requires access to /dev/video0.

Remediation

Install update from vendor's website.

References

• https://patchwork.linuxtv.org/patch/59542/
• http://www.openwall.com/lists/oss-security/2019/11/05/1
• https://lore.kernel.org/lkml/20191103221719.27118-1-alex.popov@linux.com/
• https://www.openwall.com/lists/oss-security/2019/11/02/1
• https://www.ptsecurity.com/ww-en/analytics/threatscape/pt-2019-05/