Exploiting null-dereferences in the Linux kernel
Posted by Seth Jenkins, Project Zero For a fair amount of time, null-deref bugs were a highly exploitable kernel bug class. Back when the kernel was able to access userland memory without restriction, and userland programs were still able to map the zero page, there were many easy techniques for exploiting null-deref bugs. However with the introduction of modern exploit mitigations such as SMEP and SMAP, as well as mmap_min_addr preventing unprivileged programs from mmap’ing low addresses, null-deref bugs are generally not considered a security issue in modern kernel versions. This blog post provides an exploit technique demonstrating that treating [...]