中危 CVE-2022-48853

CVE编号

CVE-2022-48853

利用情况

暂无

补丁情况

官方补丁

披露时间

2024-07-16
漏洞描述
In the Linux kernel, the following vulnerability has been resolved:

swiotlb: fix info leak with DMA_FROM_DEVICE

The problem I'm addressing was discovered by the LTP test covering
cve-2018-1000204.

A short description of what happens follows:
1) The test case issues a command code 00 (TEST UNIT READY) via the SG_IO
interface with: dxfer_len == 524288, dxdfer_dir == SG_DXFER_FROM_DEV
and a corresponding dxferp. The peculiar thing about this is that TUR
is not reading from the device.
2) In sg_start_req() the invocation of blk_rq_map_user() effectively
bounces the user-space buffer. As if the device was to transfer into
it. Since commit a45b599ad808 ("scsi: sg: allocate with __GFP_ZERO in
sg_build_indirect()") we make sure this first bounce buffer is
allocated with GFP_ZERO.
3) For the rest of the story we keep ignoring that we have a TUR, so the
device won't touch the buffer we prepare as if the we had a
DMA_FROM_DEVICE type of situation. My setup uses a virtio-scsi device
and the buffer allocated by SG is mapped by the function
virtqueue_add_split() which uses DMA_FROM_DEVICE for the "in" sgs (here
scatter-gather and not scsi generics). This mapping involves bouncing
via the swiotlb (we need swiotlb to do virtio in protected guest like
s390 Secure Execution, or AMD SEV).
4) When the SCSI TUR is done, we first copy back the content of the second
(that is swiotlb) bounce buffer (which most likely contains some
previous IO data), to the first bounce buffer, which contains all
zeros. Then we copy back the content of the first bounce buffer to
the user-space buffer.
5) The test case detects that the buffer, which it zero-initialized,
ain't all zeros and fails.

One can argue that this is an swiotlb problem, because without swiotlb
we leak all zeros, and the swiotlb should be transparent in a sense that
it does not affect the outcome (if all other participants are well
behaved).

Copying the content of the original buffer into the swiotlb buffer is
the only way I can think of to make swiotlb transparent in such
scenarios. So let's do just that if in doubt, but allow the driver
to tell us that the whole mapped buffer is going to be overwritten,
in which case we can preserve the old behavior and avoid the performance
impact of the extra bounce.
解决建议
建议您更新当前系统或软件至最新版，完成漏洞的修复。
参考链接
https://access.redhat.com/security/cve/CVE-2022-48853
https://git.kernel.org/stable/c/270475d6d2410ec66e971bf181afe1958dad565e
https://git.kernel.org/stable/c/6bfc5377a210dbda2a237f16d94d1bd4f1335026
https://git.kernel.org/stable/c/7403f4118ab94be837ab9d770507537a8057bc63
https://git.kernel.org/stable/c/8d9ac1b6665c73f23e963775f85d99679fd8e192
https://git.kernel.org/stable/c/971e5dadffd02beba1063e7dd9c3a82de17cf534
https://git.kernel.org/stable/c/c132f2ba716b5ee6b35f82226a6e5417d013d753
https://git.kernel.org/stable/c/d4d975e7921079f877f828099bb8260af335508f
https://git.kernel.org/stable/c/ddbd89deb7d32b1fbb879f48d68fda1a8ac58e8e
https://lore.kernel.org/linux-cve-announce/2024071626-CVE-2022-48853-c6d8@gregkh/T
受影响软件情况
# 类型 厂商 产品 版本 影响面
1
运行在以下环境
系统 debian_11 linux * Up to
(excluding)
5.10.113-1
运行在以下环境
系统 debian_12 linux * Up to
(excluding)
5.16.18-1
运行在以下环境
系统 linux linux_kernel * Up to
(excluding)
4.9.320
运行在以下环境
系统 linux linux_kernel * From
(including)
4.10 		Up to
(excluding)
4.14.281
运行在以下环境
系统 linux linux_kernel * From
(including)
4.15 		Up to
(excluding)
4.19.245
运行在以下环境
系统 linux linux_kernel * From
(including)
4.20 		Up to
(excluding)
5.4.189
运行在以下环境
系统 linux linux_kernel * From
(including)
5.11 		Up to
(excluding)
5.15.29
运行在以下环境
系统 linux linux_kernel * From
(including)
5.16 		Up to
(excluding)
5.16.15
运行在以下环境
系统 linux linux_kernel * From
(including)
5.5 		Up to
(excluding)
5.10.110
阿里云评分
5.0
  • 攻击路径
    本地
  • 攻击复杂度
    困难
  • 权限要求
    管控权限
  • 影响范围
    有限影响
  • EXP成熟度
    未验证
  • 补丁情况
    官方补丁
  • 数据保密性
    无影响
  • 数据完整性
    无影响
  • 服务器危害
    无影响
  • 全网数量
    N/A
CWE-ID 漏洞类型
NVD-CWE-noinfo
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