[ALAS2-2023-2268] Amazon Linux 2 2017.12 - ALAS2-2023-2268: important priority package update for kernel

Package updates are available for Amazon Linux 2 that fix the following vulnerabilities:
CVE-2023-4208:
A use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component can be exploited to achieve local privilege escalation.

When u32_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free.

We recommend upgrading past commit 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81.

CVE-2023-4206:
A use-after-free vulnerability in the Linux kernel's net/sched: cls_route component can be exploited to achieve local privilege escalation.

When route4_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free.

We recommend upgrading past commit b80b829e9e2c1b3f7aae34855e04d8f6ecaf13c8.

CVE-2023-4128:
A use-after-free flaw was found in net/sched/cls_fw.c in classifiers (cls_fw, cls_u32, and cls_route) in the Linux Kernel. This flaw allows a local attacker to perform a local privilege escalation due to incorrect handling of the existing filter, leading to a kernel information leak issue.

CVE-2023-34319:
A buffer overrun vulnerability was found in the netback driver in Xen due to an unusual split packet. This flaw allows an unprivileged guest to cause a denial of service (DoS) of the host by sending network packets to the backend, causing the backend to crash.

CVE-2023-3390:
A use-after-free vulnerability was found in the Linux kernel's netfilter subsystem in net/netfilter/nf_tables_api.c.

Mishandled error handling with NFT_MSG_NEWRULE makes it possible to use a dangling pointer in the same transaction causing a use-after-free vulnerability. This flaw allows a local attacker with user access to cause a privilege escalation issue.

We recommend upgrading past commit 1240eb93f0616b21c675416516ff3d74798fdc97.

CVE-2023-3212:
A flaw in the Linux Kernel found in the GFS2 file system. On corrupted gfs2 file systems the evict code can try to reference the journal descriptor structure, jdesc, after it has been freed and set to NULL. It can lead to null pointer dereference when gfs2_trans_begin being called and then fail ingfs2_evict_inode().