Red Hat Security Advisory: kernel security and bug fix update

Important

A flaw was found in the allocate_trace_buffer in kernel/trace/trace.c in the debug subsystem, when failure to allocate a dynamic percpu area, a resource cleanup is called. The pointer (buf->buffer) still holds the address and is not set to NULL, which can cause a use-after-free problem, leading to a dangling pointer issue.

CWE-416 - Use After Free

A use-after-free vulnerability was found in the Linux kernel’s implementation of blktrace in the __blk_add_trace function. A local attacker with permissions to run block trace instructions against a device can create a situation where the core block_trace object is used after it is freed. The attacker can pre-groom memory to race this use-after-free to create a condition where the memory is corrupted and cause privilege escalation. The ability to create this condition requires elevated privileges, and it has been decided that this change in Red Hat Enterprise Linux 5 and 6 would risk introducing possible regressions and will not be backported.

CWE-416 - Use After Free