Bug 2323943 (CVE-2024-50134)

Summary: CVE-2024-50134 kernel: drm/vboxvideo: Replace fake VLA at end of vbva_mouse_pointer_shape with real VLA
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: low    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Bug Depends On: 2324013    
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Description OSIDB Bzimport 2024-11-05 18:03:41 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/vboxvideo: Replace fake VLA at end of vbva_mouse_pointer_shape with real VLA

Replace the fake VLA at end of the vbva_mouse_pointer_shape shape with
a real VLA to fix a "memcpy: detected field-spanning write error" warning:

[   13.319813] memcpy: detected field-spanning write (size 16896) of single field "p->data" at drivers/gpu/drm/vboxvideo/hgsmi_base.c:154 (size 4)
[   13.319841] WARNING: CPU: 0 PID: 1105 at drivers/gpu/drm/vboxvideo/hgsmi_base.c:154 hgsmi_update_pointer_shape+0x192/0x1c0 [vboxvideo]
[   13.320038] Call Trace:
[   13.320173]  hgsmi_update_pointer_shape [vboxvideo]
[   13.320184]  vbox_cursor_atomic_update [vboxvideo]

Note as mentioned in the added comment it seems the original length
calculation for the allocated and send hgsmi buffer is 4 bytes too large.
Changing this is not the goal of this patch, so this behavior is kept.
Comment 1 Robb Gatica 2024-11-05 20:58:21 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024110558-CVE-2024-50134-53ce@gregkh/T