| 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-2022-48674: erofs: fix pcluster use-after-free on UP platforms |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| erofs: fix pcluster use-after-free on UP platforms |
| |
| During stress testing with CONFIG_SMP disabled, KASAN reports as below: |
| |
| ================================================================== |
| BUG: KASAN: use-after-free in __mutex_lock+0xe5/0xc30 |
| Read of size 8 at addr ffff8881094223f8 by task stress/7789 |
| |
| CPU: 0 PID: 7789 Comm: stress Not tainted 6.0.0-rc1-00002-g0d53d2e882f9 #3 |
| Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 |
| Call Trace: |
| <TASK> |
| .. |
| __mutex_lock+0xe5/0xc30 |
| .. |
| z_erofs_do_read_page+0x8ce/0x1560 |
| .. |
| z_erofs_readahead+0x31c/0x580 |
| .. |
| Freed by task 7787 |
| kasan_save_stack+0x1e/0x40 |
| kasan_set_track+0x20/0x30 |
| kasan_set_free_info+0x20/0x40 |
| __kasan_slab_free+0x10c/0x190 |
| kmem_cache_free+0xed/0x380 |
| rcu_core+0x3d5/0xc90 |
| __do_softirq+0x12d/0x389 |
| |
| Last potentially related work creation: |
| kasan_save_stack+0x1e/0x40 |
| __kasan_record_aux_stack+0x97/0xb0 |
| call_rcu+0x3d/0x3f0 |
| erofs_shrink_workstation+0x11f/0x210 |
| erofs_shrink_scan+0xdc/0x170 |
| shrink_slab.constprop.0+0x296/0x530 |
| drop_slab+0x1c/0x70 |
| drop_caches_sysctl_handler+0x70/0x80 |
| proc_sys_call_handler+0x20a/0x2f0 |
| vfs_write+0x555/0x6c0 |
| ksys_write+0xbe/0x160 |
| do_syscall_64+0x3b/0x90 |
| |
| The root cause is that erofs_workgroup_unfreeze() doesn't reset to |
| orig_val thus it causes a race that the pcluster reuses unexpectedly |
| before freeing. |
| |
| Since UP platforms are quite rare now, such path becomes unnecessary. |
| Let's drop such specific-designed path directly instead. |
| |
| The Linux kernel CVE team has assigned CVE-2022-48674 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.0 with commit 73f5c66df3e26ab750cefcb9a3e08c71c9f79cad and fixed in 5.15.68 with commit 8ddd001cef5e82d19192e6861068463ecca5f556 |
| Issue introduced in 5.0 with commit 73f5c66df3e26ab750cefcb9a3e08c71c9f79cad and fixed in 5.19.9 with commit 94c34faaafe7b55adc2d8d881db195b646959b9e |
| Issue introduced in 5.0 with commit 73f5c66df3e26ab750cefcb9a3e08c71c9f79cad and fixed in 6.0 with commit 2f44013e39984c127c6efedf70e6b5f4e9dcf315 |
| Issue introduced in 4.19.26 with commit 08ec9e6892cc792d7f8fe4d13bd8a0e91fb23488 |
| Issue introduced in 4.20.13 with commit 78c46113413bea1cc345757112aa2642e0f66de5 |
| |
| 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-2022-48674 |
| 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: |
| fs/erofs/internal.h |
| |
| |
| 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/8ddd001cef5e82d19192e6861068463ecca5f556 |
| https://git.kernel.org/stable/c/94c34faaafe7b55adc2d8d881db195b646959b9e |
| https://git.kernel.org/stable/c/2f44013e39984c127c6efedf70e6b5f4e9dcf315 |
