Bug 1227722 (CVE-2024-39497) - VUL-0: CVE-2024-39497: kernel: drm/shmem-helper: fix BUG_ON() on mmap(PROT_WRITE, MAP_PRIVATE)
Summary: VUL-0: CVE-2024-39497: kernel: drm/shmem-helper: fix BUG_ON() on mmap(PROT_WR...
Status: IN_PROGRESS
Alias: CVE-2024-39497
Product: SUSE Security Incidents
Classification: Novell Products
Component: Incidents (show other bugs)
Version: unspecified
Hardware: Other Other
: P3 - Medium : Normal
Target Milestone: ---
Assignee: Security Team bot
QA Contact: Security Team bot
URL: https://smash.suse.de/issue/413812/
Whiteboard: CVSSv3.1:SUSE:CVE-2024-39497:5.5:(AV:...
Keywords:
Depends on:
Blocks:
 
Reported: 2024-07-12 17:41 UTC by SMASH SMASH
Modified: 2024-07-17 06:48 UTC (History)
5 users (show)

See Also:
Found By: Security Response Team
Services Priority:
Business Priority:
Blocker: ---
Marketing QA Status: ---
IT Deployment: ---

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Description SMASH SMASH 2024-07-12 17:41:51 UTC 
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:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-39497
https://www.cve.org/CVERecord?id=CVE-2024-39497
https://git.kernel.org/stable/c/03c71c42809ef4b17f5d874cdb2d3bf40e847b86
https://git.kernel.org/stable/c/1b4a8b89bf6787090b56424d269bf84ba00c3263
https://git.kernel.org/stable/c/39bc27bd688066a63e56f7f64ad34fae03fbe3b8
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2024/CVE-2024-39497.mbox