MGASA-2022-0264

This kernel-linus update is based on upstream 5.15.55 and fixes at least the following security issues:

There are use-after-free vulnerabilities caused by timer handler in net/rose/rose_timer.c of linux that allow attackers to crash linux kernel without any privileges (CVE-2022-2318).

Xen Block and Network PV device frontends don't zero memory regions before sharing them with the backend (CVE-2022-26365, CVE-2022-33740, XSA-403). Additionally the granularity of the grant table doesn't allow sharing less than a 4K page, leading to unrelated data residing in the same 4K page as data shared with a backend being accessible by such backend (CVE-2022-33741, CVE-2022-33742, XSA-403).

Xen network backend may cause Linux netfront to use freed SKBs While adding logic to support XDP (eXpress Data Path), a code label was moved in a way allowing for SKBs having references (pointers) retained for further processing to nevertheless be freed (CVE-2022-33743, XSA-405).

Xen Arm guests can cause Dom0 DoS via PV devices When mapping pages of guests on Arm, dom0 is using an rbtree to keep track of the foreign mappings. Updating of that rbtree is not always done completely with the related lock held, resulting in a small race window, which can be used by unprivileged guests via PV devices to cause inconsistencies of the rbtree. These in consistencies can lead to Denial of Service (DoS) of dom0, e.g. by causing crashes or the inability to perform further mappings of other guests memory pages (CVE-2022-33744, XSA-406).

An issue was discovered in the Linux kernel through 5.18.9. A type confusion bug in nftseteleminit (leading to a buffer overflow) could be used by a local attacker to escalate privileges (The attacker can obtain root access, but must start with an unprivileged user namespace to obtain CAPNET_ADMIN access) (CVE-2022-34918).

For other upstream fixes, see the referenced changelogs.