cve/2024/CVE-2024-39497.md

CVE-2024-39497

Description

In the Linux kernel, the following vulnerability has been resolved:drm/shmem-helper: Fix BUG_ON() on mmap(PROT_WRITE, MAP_PRIVATE)Lack of check for copy-on-write (COW) mapping in drm_gem_shmem_mmapallows users to call mmap with PROT_WRITE and MAP_PRIVATE flagcausing a kernel panic due to BUG_ON in vmf_insert_pfn_prot:BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));Return -EINVAL early if COW mapping is detected.This bug affects all drm drivers using default shmem helpers.It can be reproduced by this simple example:void *ptr = mmap(0, size, PROT_WRITE, MAP_PRIVATE, fd, mmap_offset);ptr[0] = 0;

POC

Reference

No PoCs from references.

Github

• https://github.com/w4zu/Debian_security