中危 binder:修复空地块的 async_free_space 核算 (CVE-2021-46935)

CVE编号

CVE-2021-46935

利用情况

暂无

补丁情况

官方补丁

披露时间

2024-02-27
漏洞描述
In the Linux kernel, the following vulnerability has been resolved:

binder: fix async_free_space accounting for empty parcels

In 4.13, commit 74310e06be4d ("android: binder: Move buffer out of area shared with user space")
fixed a kernel structure visibility issue. As part of that patch,
sizeof(void *) was used as the buffer size for 0-length data payloads so
the driver could detect abusive clients sending 0-length asynchronous
transactions to a server by enforcing limits on async_free_size.

Unfortunately, on the "free" side, the accounting of async_free_space
did not add the sizeof(void *) back. The result was that up to 8-bytes of
async_free_space were leaked on every async transaction of 8-bytes or
less. These small transactions are uncommon, so this accounting issue
has gone undetected for several years.

The fix is to use "buffer_size" (the allocated buffer size) instead of
"size" (the logical buffer size) when updating the async_free_space
during the free operation. These are the same except for this
corner case of asynchronous transactions with payloads < 8 bytes.
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。
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_10 linux * Up to
(excluding)
4.19.232-1
运行在以下环境
系统 debian_11 linux * Up to
(excluding)
5.10.92-1
运行在以下环境
系统 debian_12 linux * Up to
(excluding)
5.15.15-1
运行在以下环境
系统 linux linux_kernel * From
(including)
4.14.0
Up to
(excluding)
4.14.261
运行在以下环境
系统 linux linux_kernel * From
(including)
4.15.0
Up to
(excluding)
4.19.224
运行在以下环境
系统 linux linux_kernel * From
(including)
4.20.0
Up to
(excluding)
5.4.170
运行在以下环境
系统 linux linux_kernel * From
(including)
5.11.0
Up to
(excluding)
5.15.13
运行在以下环境
系统 linux linux_kernel * From
(including)
5.5.0
Up to
(excluding)
5.10.90
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
CWE-668 将资源暴露给错误范围
阿里云安全产品覆盖情况