| 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-2022-48969: xen-netfront: Fix NULL sring after live migration |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| xen-netfront: Fix NULL sring after live migration |
| |
| A NAPI is setup for each network sring to poll data to kernel |
| The sring with source host is destroyed before live migration and |
| new sring with target host is setup after live migration. |
| The NAPI for the old sring is not deleted until setup new sring |
| with target host after migration. With busy_poll/busy_read enabled, |
| the NAPI can be polled before got deleted when resume VM. |
| |
| BUG: unable to handle kernel NULL pointer dereference at |
| 0000000000000008 |
| IP: xennet_poll+0xae/0xd20 |
| PGD 0 P4D 0 |
| Oops: 0000 [#1] SMP PTI |
| Call Trace: |
| finish_task_switch+0x71/0x230 |
| timerqueue_del+0x1d/0x40 |
| hrtimer_try_to_cancel+0xb5/0x110 |
| xennet_alloc_rx_buffers+0x2a0/0x2a0 |
| napi_busy_loop+0xdb/0x270 |
| sock_poll+0x87/0x90 |
| do_sys_poll+0x26f/0x580 |
| tracing_map_insert+0x1d4/0x2f0 |
| event_hist_trigger+0x14a/0x260 |
| |
| finish_task_switch+0x71/0x230 |
| __schedule+0x256/0x890 |
| recalc_sigpending+0x1b/0x50 |
| xen_sched_clock+0x15/0x20 |
| __rb_reserve_next+0x12d/0x140 |
| ring_buffer_lock_reserve+0x123/0x3d0 |
| event_triggers_call+0x87/0xb0 |
| trace_event_buffer_commit+0x1c4/0x210 |
| xen_clocksource_get_cycles+0x15/0x20 |
| ktime_get_ts64+0x51/0xf0 |
| SyS_ppoll+0x160/0x1a0 |
| SyS_ppoll+0x160/0x1a0 |
| do_syscall_64+0x73/0x130 |
| entry_SYSCALL_64_after_hwframe+0x41/0xa6 |
| ... |
| RIP: xennet_poll+0xae/0xd20 RSP: ffffb4f041933900 |
| CR2: 0000000000000008 |
| ---[ end trace f8601785b354351c ]--- |
| |
| xen frontend should remove the NAPIs for the old srings before live |
| migration as the bond srings are destroyed |
| |
| There is a tiny window between the srings are set to NULL and |
| the NAPIs are disabled, It is safe as the NAPI threads are still |
| frozen at that time |
| |
| The Linux kernel CVE team has assigned CVE-2022-48969 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 2.6.24 with commit 4ec2411980d0fd2995e8dea8a06fe57aa47523cb and fixed in 4.19.269 with commit 99859947517e446058ad7243ee81d2f9801fa3dd |
| Issue introduced in 2.6.24 with commit 4ec2411980d0fd2995e8dea8a06fe57aa47523cb and fixed in 5.4.227 with commit ed773dd798bf720756d20021b8d8a4a3d7184bda |
| Issue introduced in 2.6.24 with commit 4ec2411980d0fd2995e8dea8a06fe57aa47523cb and fixed in 5.10.159 with commit e6860c889f4ad50b6ab696f5ea154295d72cf27a |
| Issue introduced in 2.6.24 with commit 4ec2411980d0fd2995e8dea8a06fe57aa47523cb and fixed in 5.15.83 with commit e6e897d4fe2f89c0bd94600a40bedf5e6e75e050 |
| Issue introduced in 2.6.24 with commit 4ec2411980d0fd2995e8dea8a06fe57aa47523cb and fixed in 6.0.13 with commit f2dd60fd3fe98bd36a91b0c6e10bfe9d66258f84 |
| Issue introduced in 2.6.24 with commit 4ec2411980d0fd2995e8dea8a06fe57aa47523cb and fixed in 6.1 with commit d50b7914fae04d840ce36491d22133070b18cca9 |
| |
| 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-2022-48969 |
| 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/xen-netfront.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/99859947517e446058ad7243ee81d2f9801fa3dd |
| https://git.kernel.org/stable/c/ed773dd798bf720756d20021b8d8a4a3d7184bda |
| https://git.kernel.org/stable/c/e6860c889f4ad50b6ab696f5ea154295d72cf27a |
| https://git.kernel.org/stable/c/e6e897d4fe2f89c0bd94600a40bedf5e6e75e050 |
| https://git.kernel.org/stable/c/f2dd60fd3fe98bd36a91b0c6e10bfe9d66258f84 |
| https://git.kernel.org/stable/c/d50b7914fae04d840ce36491d22133070b18cca9 |
