| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-44973: mm, slub: do not call do_slab_free for kfence object |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| mm, slub: do not call do_slab_free for kfence object |
| |
| In 782f8906f805 the freeing of kfence objects was moved from deep |
| inside do_slab_free to the wrapper functions outside. This is a nice |
| change, but unfortunately it missed one spot in __kmem_cache_free_bulk. |
| |
| This results in a crash like this: |
| |
| BUG skbuff_head_cache (Tainted: G S B E ): Padding overwritten. 0xffff88907fea0f00-0xffff88907fea0fff @offset=3840 |
| |
| slab_err (mm/slub.c:1129) |
| free_to_partial_list (mm/slub.c:? mm/slub.c:4036) |
| slab_pad_check (mm/slub.c:864 mm/slub.c:1290) |
| check_slab (mm/slub.c:?) |
| free_to_partial_list (mm/slub.c:3171 mm/slub.c:4036) |
| kmem_cache_alloc_bulk (mm/slub.c:? mm/slub.c:4495 mm/slub.c:4586 mm/slub.c:4635) |
| napi_build_skb (net/core/skbuff.c:348 net/core/skbuff.c:527 net/core/skbuff.c:549) |
| |
| All the other callers to do_slab_free appear to be ok. |
| |
| Add a kfence_free check in __kmem_cache_free_bulk to avoid the crash. |
| |
| The Linux kernel CVE team has assigned CVE-2024-44973 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.8 with commit 782f8906f8057efc7151b4b98b0a0280a71d005f and fixed in 6.10.5 with commit b35cd7f1e969aaa63e6716d82480f6b8a3230949 |
| Issue introduced in 6.8 with commit 782f8906f8057efc7151b4b98b0a0280a71d005f and fixed in 6.11 with commit a371d558e6f3aed977a8a7346350557de5d25190 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2024-44973 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| mm/slub.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/b35cd7f1e969aaa63e6716d82480f6b8a3230949 |
| https://git.kernel.org/stable/c/a371d558e6f3aed977a8a7346350557de5d25190 |
