drm/xe/hmm: Don't dereference struct page pointers without notifier lock
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.12.19, 6.13.7
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: total
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/xe/hmm: Don't dereference struct page pointers without notifier lock The pnfs that we obtain from hmm_range_fault() point to pages that we don't have a reference on, and the guarantee that they are still in the cpu page-tables is that the notifier lock must be held and the notifier seqno is still valid. So while building the sg table and marking the pages accesses / dirty we need to hold this lock with a validated seqno. However, the lock is reclaim tainted which makes sg_alloc_table_from_pages_segment() unusable, since it internally allocates memory. Instead build the sg-table manually. For the non-iommu case this might lead to fewer coalesces, but if that's a problem it can be fixed up later in the resource cursor code. For the iommu case, the whole sg-table may still be coalesced to a single contigous device va region. This avoids marking pages that we don't own dirty and accessed, and it also avoid dereferencing struct pages that we don't own. v2: • Use assert to check whether hmm pfns are valid (Matthew Auld) • Take into account that large pages may cross range boundaries (Matthew Auld) v3: • Don't unnecessarily check for a non-freed sg-table. (Matthew Auld) • Add a missing up_read() in an error path. (Matthew Auld) (cherry picked from commit ea3e66d280ce2576664a862693d1da8fd324c317)
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- Linux Linux
From 81e058a3e7fd8593d076b4f26f7b8bb49f1d61e3 · fixed in 2a24c98f0e4cc994334598d4f3a851972064809d; From 81e058a3e7fd8593d076b4f26f7b8bb49f1d61e3 · fixed in f9326f529da7298a95643c3267f1c0fdb0db55eb; From 81e058a3e7fd8593d076b4f26f7b8bb49f1d61e3 · fixed in 0a98219bcc961edd3388960576e4353e123b4a51
- Linux Linux
6.10
- KernelLinux
From 6.10.0 · fixed in 6.12.19; From 6.13.0 · fixed in 6.13.7