SB2020011410 - Red Hat update for kernel-rt
Published: January 14, 2020
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 3 secuirty vulnerabilities.
1) Improper access control (CVE-ID: CVE-2018-18281)
The vulnerability allows a local user to bypass certain security restrictions.
The vulnerability exists due to improper access restrictions to memory when performing TLB flushes after dropping pagetable locks with mremap() syscall, A local user can access a physical page of a stale TLB entry after ftruncate() syscall is called to remove entries from the pagetables of a task that is in the middle of mremap() syscall.
Successful exploitation of the vulnerability may allow an attacker to gain access to sensitive information, stored in process memory.
2) Use-after-free (CVE-ID: CVE-2018-20856)
The vulnerability allows a local attacker to execute arbitrary code on a targeted system.
The vulnerability exists due to a use-after-free error when the "__blk_drain_queue()" function in the "block/blk-core.c" file mishandles error cases. A local authenticated attacker can access the system and execute an application that submits malicious input, cause a use-after-free memory operation error and execute arbitrary code on the targeted system.
Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.
3) Race condition (CVE-ID: CVE-2019-11599)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a race condition with mmget_not_zero or get_task_mm calls and is related to fs/userfaultfd.c, mm/mmap.c, fs/proc/task_mmu.c, and drivers/infiniband/core/uverbs_main.c due to kernel does not use locking or other mechanisms to prevent vma layout or vma flags changes while it runs. A local user can exploit the race and gain unauthorized access to sensitive information and escalate privileges on the system.
Remediation
Install update from vendor's website.