| 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-2022-48649: mm/slab_common: fix possible double free of kmem_cache |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| mm/slab_common: fix possible double free of kmem_cache |
| |
| When doing slub_debug test, kfence's 'test_memcache_typesafe_by_rcu' |
| kunit test case cause a use-after-free error: |
| |
| BUG: KASAN: use-after-free in kobject_del+0x14/0x30 |
| Read of size 8 at addr ffff888007679090 by task kunit_try_catch/261 |
| |
| CPU: 1 PID: 261 Comm: kunit_try_catch Tainted: G B N 6.0.0-rc5-next-20220916 #17 |
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 |
| Call Trace: |
| <TASK> |
| dump_stack_lvl+0x34/0x48 |
| print_address_description.constprop.0+0x87/0x2a5 |
| print_report+0x103/0x1ed |
| kasan_report+0xb7/0x140 |
| kobject_del+0x14/0x30 |
| kmem_cache_destroy+0x130/0x170 |
| test_exit+0x1a/0x30 |
| kunit_try_run_case+0xad/0xc0 |
| kunit_generic_run_threadfn_adapter+0x26/0x50 |
| kthread+0x17b/0x1b0 |
| </TASK> |
| |
| The cause is inside kmem_cache_destroy(): |
| |
| kmem_cache_destroy |
| acquire lock/mutex |
| shutdown_cache |
| schedule_work(kmem_cache_release) (if RCU flag set) |
| release lock/mutex |
| kmem_cache_release (if RCU flag not set) |
| |
| In some certain timing, the scheduled work could be run before |
| the next RCU flag checking, which can then get a wrong value |
| and lead to double kmem_cache_release(). |
| |
| Fix it by caching the RCU flag inside protected area, just like 'refcnt' |
| |
| The Linux kernel CVE team has assigned CVE-2022-48649 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.19.8 with commit 357321557920c805de2b14832002465c320eea4f and fixed in 5.19.12 with commit c673c6ceac53fb2e631c9fbbd79957099a08927f |
| |
| 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-2022-48649 |
| 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/slab_common.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/c673c6ceac53fb2e631c9fbbd79957099a08927f |
| https://git.kernel.org/stable/c/d71608a877362becdc94191f190902fac1e64d35 |
