CVE-2022-0847: 
Linux Kernel vulnerability analysis and mitigation

The Dirty Pipe vulnerability (CVE-2022-0847) was discovered in March 2022, affecting Linux kernel versions 5.8 and later. The vulnerability stems from an improper initialization of the "flags" member in the new pipe buffer structure within the copypagetoiterpipe and push_pipe functions. This flaw allows unprivileged local users to write to pages in the page cache backed by read-only files, potentially leading to privilege escalation (Dirty Pipe, CVE Mitre).

The vulnerability exists due to the uninitialized "flags" member of the pipe buffer structure, which was introduced in Linux 4.9 but became exploitable in version 5.8 with commit f6dd975583bd. The flaw allows attackers to inject PIPEBUFFLAGCANMERGE into a page cache reference, enabling them to overwrite data in the page cache by writing new data into specially prepared pipes. This works even without write permissions and affects immutable files, read-only btrfs snapshots, and read-only mounts (Dirty Pipe).

The vulnerability enables unprivileged local users to write to pages in the page cache backed by read-only files, potentially leading to privilege escalation. This can result in unauthorized data modification, information disclosure, or denial of service. The impact is particularly severe as it works on read-only file systems and with immutable files (Red Hat CVE, Ubuntu Security).

The vulnerability was fixed in Linux kernel versions 5.16.11, 5.15.25, and 5.10.102. Users are strongly advised to update their systems to these versions or later. There are no known workarounds other than applying the security updates (SUSE KB, NetApp Advisory).