| 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-2022-49014: net: tun: Fix use-after-free in tun_detach() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| net: tun: Fix use-after-free in tun_detach() |
| |
| syzbot reported use-after-free in tun_detach() [1]. This causes call |
| trace like below: |
| |
| ================================================================== |
| BUG: KASAN: use-after-free in notifier_call_chain+0x1ee/0x200 kernel/notifier.c:75 |
| Read of size 8 at addr ffff88807324e2a8 by task syz-executor.0/3673 |
| |
| CPU: 0 PID: 3673 Comm: syz-executor.0 Not tainted 6.1.0-rc5-syzkaller-00044-gcc675d22e422 #0 |
| Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 |
| Call Trace: |
| <TASK> |
| __dump_stack lib/dump_stack.c:88 [inline] |
| dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106 |
| print_address_description mm/kasan/report.c:284 [inline] |
| print_report+0x15e/0x461 mm/kasan/report.c:395 |
| kasan_report+0xbf/0x1f0 mm/kasan/report.c:495 |
| notifier_call_chain+0x1ee/0x200 kernel/notifier.c:75 |
| call_netdevice_notifiers_info+0x86/0x130 net/core/dev.c:1942 |
| call_netdevice_notifiers_extack net/core/dev.c:1983 [inline] |
| call_netdevice_notifiers net/core/dev.c:1997 [inline] |
| netdev_wait_allrefs_any net/core/dev.c:10237 [inline] |
| netdev_run_todo+0xbc6/0x1100 net/core/dev.c:10351 |
| tun_detach drivers/net/tun.c:704 [inline] |
| tun_chr_close+0xe4/0x190 drivers/net/tun.c:3467 |
| __fput+0x27c/0xa90 fs/file_table.c:320 |
| task_work_run+0x16f/0x270 kernel/task_work.c:179 |
| exit_task_work include/linux/task_work.h:38 [inline] |
| do_exit+0xb3d/0x2a30 kernel/exit.c:820 |
| do_group_exit+0xd4/0x2a0 kernel/exit.c:950 |
| get_signal+0x21b1/0x2440 kernel/signal.c:2858 |
| arch_do_signal_or_restart+0x86/0x2300 arch/x86/kernel/signal.c:869 |
| exit_to_user_mode_loop kernel/entry/common.c:168 [inline] |
| exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:203 |
| __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] |
| syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296 |
| do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 |
| entry_SYSCALL_64_after_hwframe+0x63/0xcd |
| |
| The cause of the issue is that sock_put() from __tun_detach() drops |
| last reference count for struct net, and then notifier_call_chain() |
| from netdev_state_change() accesses that struct net. |
| |
| This patch fixes the issue by calling sock_put() from tun_detach() |
| after all necessary accesses for the struct net has done. |
| |
| The Linux kernel CVE team has assigned CVE-2022-49014 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.17 with commit 83c1f36f9880814b24cdf6c2f91f66f61db65326 and fixed in 4.19.268 with commit 1f23f1890d91812c35d32eab1b49621b6d32dc7b |
| Issue introduced in 4.17 with commit 83c1f36f9880814b24cdf6c2f91f66f61db65326 and fixed in 5.4.226 with commit 16c244bc65d1175775325ec0489a5a5c830e02c7 |
| Issue introduced in 4.17 with commit 83c1f36f9880814b24cdf6c2f91f66f61db65326 and fixed in 5.10.158 with commit 5f442e1d403e0496bacb74a58e2be7f500695e6f |
| Issue introduced in 4.17 with commit 83c1f36f9880814b24cdf6c2f91f66f61db65326 and fixed in 5.15.82 with commit 04b995e963229501401810dab89dc73e7f12d054 |
| Issue introduced in 4.17 with commit 83c1f36f9880814b24cdf6c2f91f66f61db65326 and fixed in 6.0.12 with commit 4cde8da2d814a3b7b176db81922d4ddaad7c0f0e |
| Issue introduced in 4.17 with commit 83c1f36f9880814b24cdf6c2f91f66f61db65326 and fixed in 6.1 with commit 5daadc86f27ea4d691e2131c04310d0418c6cd12 |
| |
| 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-2022-49014 |
| 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: |
| drivers/net/tun.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/1f23f1890d91812c35d32eab1b49621b6d32dc7b |
| https://git.kernel.org/stable/c/16c244bc65d1175775325ec0489a5a5c830e02c7 |
| https://git.kernel.org/stable/c/5f442e1d403e0496bacb74a58e2be7f500695e6f |
| https://git.kernel.org/stable/c/04b995e963229501401810dab89dc73e7f12d054 |
| https://git.kernel.org/stable/c/4cde8da2d814a3b7b176db81922d4ddaad7c0f0e |
| https://git.kernel.org/stable/c/5daadc86f27ea4d691e2131c04310d0418c6cd12 |
