| 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-2022-48862: vhost: fix hung thread due to erroneous iotlb entries |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| vhost: fix hung thread due to erroneous iotlb entries |
| |
| In vhost_iotlb_add_range_ctx(), range size can overflow to 0 when |
| start is 0 and last is ULONG_MAX. One instance where it can happen |
| is when userspace sends an IOTLB message with iova=size=uaddr=0 |
| (vhost_process_iotlb_msg). So, an entry with size = 0, start = 0, |
| last = ULONG_MAX ends up in the iotlb. Next time a packet is sent, |
| iotlb_access_ok() loops indefinitely due to that erroneous entry. |
| |
| Call Trace: |
| <TASK> |
| iotlb_access_ok+0x21b/0x3e0 drivers/vhost/vhost.c:1340 |
| vq_meta_prefetch+0xbc/0x280 drivers/vhost/vhost.c:1366 |
| vhost_transport_do_send_pkt+0xe0/0xfd0 drivers/vhost/vsock.c:104 |
| vhost_worker+0x23d/0x3d0 drivers/vhost/vhost.c:372 |
| kthread+0x2e9/0x3a0 kernel/kthread.c:377 |
| ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 |
| </TASK> |
| |
| Reported by syzbot at: |
| https://syzkaller.appspot.com/bug?extid=0abd373e2e50d704db87 |
| |
| To fix this, do two things: |
| |
| 1. Return -EINVAL in vhost_chr_write_iter() when userspace asks to map |
| a range with size 0. |
| 2. Fix vhost_iotlb_add_range_ctx() to handle the range [0, ULONG_MAX] |
| by splitting it into two entries. |
| |
| The Linux kernel CVE team has assigned CVE-2022-48862 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.7 with commit 0bbe30668d89ec8a309f28ced6d092c90fb23e8c and fixed in 5.15.29 with commit f8d88e86e90ea1002226d7ac2430152bfea003d1 |
| Issue introduced in 5.7 with commit 0bbe30668d89ec8a309f28ced6d092c90fb23e8c and fixed in 5.16.15 with commit d9a747e6b6561280bf1791bb24c5e9e082193dad |
| Issue introduced in 5.7 with commit 0bbe30668d89ec8a309f28ced6d092c90fb23e8c and fixed in 5.17 with commit e2ae38cf3d91837a493cb2093c87700ff3cbe667 |
| |
| 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-2022-48862 |
| 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/vhost/iotlb.c |
| drivers/vhost/vhost.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/f8d88e86e90ea1002226d7ac2430152bfea003d1 |
| https://git.kernel.org/stable/c/d9a747e6b6561280bf1791bb24c5e9e082193dad |
| https://git.kernel.org/stable/c/e2ae38cf3d91837a493cb2093c87700ff3cbe667 |
