MGASA-2021-0205

This kernel-linus update is based on upstream 5.10.33 and fixes at least the following security issues:

A race condition in Linux kernel SCTP sockets (net/sctp/socket.c) before 5.12-rc8 can lead to kernel privilege escalation from the context of a network service or an unprivileged process. If sctpdestroysock is called without socknet(sk)->sctp.addrwqlock then an element is removed from the autoasconfsplist list without any proper locking. This can be exploited by an attacker with network service privileges to escalate to root or from the context of an unprivileged user directly if a BPFCGROUPINETSOCK_CREATE is attached which denies creation of some SCTP socket (CVE-2021-23133).

An issue was discovered in the Linux kernel through 5.11.x. kernel/bpf/ verifier.c performs undesirable out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory. Specifically, for sequences of pointer arithmetic operations, the pointer modification performed by the first operation is not correctly accounted for when restricting subsequent operations (CVE-2021-29155).

For other upstream fixes, see the referenced changelogs.