CVE-2025-71130

Description

In the Linux kernel, the following vulnerability has been resolved:drm/i915/gem: Zero-initialize the eb.vma array in i915_gem_do_execbufferInitialize the eb.vma array with values of 0 when the eb structure isfirst set up. In particular, this sets the eb->vma[i].vma pointers tonull, simplifying cleanup and getting rid of the bug described below.During the execution of eb_lookup_vmas(), the eb->vma array issuccessively filled up with struct eb_vma objects. This process includescalling eb_add_vma(), which might fail; however, even in the event offailure, eb->vma[i].vma is set for the currently processed buffer.If eb_add_vma() fails, eb_lookup_vmas() returns with an error, whichprompts a call to eb_release_vmas() to clean up the mess. Sinceeb_lookup_vmas() might fail during processing any (possibly not first)buffer, eb_release_vmas() checks whether a buffers vma is null to knowat what point did the lookup function fail.In eb_lookup_vmas(), eb->vma[i].vma is set to null if either the helperfunction eb_lookup_vma() or eb_validate_vma() fails. eb->vma[i+1].vma isset to null in case i915_gem_object_userptr_submit_init() fails; thecurrent one needs to be cleaned up by eb_release_vmas() at this point,so the next one is set. If eb_add_vma() fails, neither the current northe next vma is set to null, which is a source of a null deref bugdescribed in the issue linked in the Closes tag.When entering eb_lookup_vmas(), the vma pointers are set to the slabpoison value, instead of null. This doesnt matter for the actuallookup, since it gets overwritten anyway, however the eb_release_vmas()function only recognizes null as the stopping value, hence the pointersare being set to null as they go in case of intermediate failure. Thispatch changes the approach to filling them all with null at the startinstead, rather than handling that manually during failure.(cherry picked from commit 08889b706d4f0b8d2352b7ca29c2d8df4d0787cd)

Risk Information

Associated Vulnerability

Patch Details

References

https://nvd.nist.gov/vuln/detail/CVE-2023-1234
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1234