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Vulnerability CVE-2024-39497
Published: 2024-07-12
| 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_mmap
allows users to call mmap with PROT_WRITE and MAP_PRIVATE flag
causing 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; |
References: |
https://git.kernel.org/stable/c/1b4a8b89bf6787090b56424d269bf84ba00c3263
https://git.kernel.org/stable/c/03c71c42809ef4b17f5d874cdb2d3bf40e847b86
https://git.kernel.org/stable/c/39bc27bd688066a63e56f7f64ad34fae03fbe3b8
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