CVE-2022-49065: 
Linux Kernel vulnerability analysis and mitigation

CVE-2022-49065 is a vulnerability in the Linux kernel's SUNRPC (Remote Procedure Call) subsystem that was discovered in 2022. The vulnerability specifically affects the svcdeferredevent trace class functionality. The issue occurs when an svc_rqst is deferred while the sunrpc tracing subsystem is enabled, which can lead to a NULL pointer dereference crash (Kernel Git).

The vulnerability stems from a NULL pointer dereference in the svcdeferredevent trace class. The issue arises because svc_revisit() sets dr->xprt to NULL, making it unreliable for providing the remote's address in the tracepoint. The problem is related to unsafe dereferences in event format specifiers, specifically when using the '%pISpc' format specifier with a 'struct sockaddr *' (Kernel Git).

When exploited, this vulnerability can cause a NULL pointer dereference crash in the Linux kernel when specific conditions are met, particularly when the sunrpc tracing subsystem is enabled and an svc_rqst is deferred (Kernel Git).

A fix has been implemented that takes a brute-force approach similar to the svcrdmaqperror tracepoint. The solution converts the dr::addr field into a presentation address in the TPfastassign() arm of the trace event and stores it as a string. This fix has been backported to stable kernels. Additionally, with the introduction of commit c6ced22997ad in v5.18, a more elegant solution using __sockaddr() became available (Kernel Git).