一、漏洞信息
漏洞编号：CVE-2024-26720
漏洞归属组件：kernel
漏洞归属的版本：4.19.140,4.19.194,4.19.90,5.10.0,6.1.0,6.1.14,6.1.19,6.1.5,6.1.6,6.1.8,6.4.0
CVSS V2.0分值：
BaseScore：0.0 Low
Vector：CVSS：2.0/
漏洞简述：
In the Linux kernel, the following vulnerability has been resolved:mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again(struct dirty_throttle_control *)->thresh is an unsigned long, but ispassed as the u32 divisor argument to div_u64(). On architectures whereunsigned long is 64 bytes, the argument will be implicitly truncated.Use div64_u64() instead of div_u64() so that the value used in the isthis a safe division check is the same as the divisor.Also, remove redundant cast of the numerator to u64, as that should happenimplicitly.This would be difficult to exploit in memcg domain, given the ratio-basedarithmetic domain_drity_limits() uses, but is much easier in globalwriteback domain with a BDI_CAP_STRICTLIMIT-backing device, using e.g. vm.dirty_bytes=(1<<32)*PAGE_SIZE so that dtc->thresh == (1<<32)
漏洞公开时间：2024-04-03 23:15:53
漏洞创建时间：2024-04-14 09:46:45
漏洞详情参考链接：
https://nvd.nist.gov/vuln/detail/CVE-2024-26720

漏洞分析指导链接：
https://gitee.com/openeuler/cve-manager/blob/master/cve-vulner-manager/doc/md/manual.md
漏洞数据来源:
openBrain开源漏洞感知系统
漏洞补丁信息：

二、漏洞分析结构反馈
影响性分析说明：
In the Linux kernel, the following vulnerability has been resolved:mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again(struct dirty_throttle_control *)->thresh is an unsigned long, but ispassed as the u32 divisor argument to div_u64(). On architectures whereunsigned long is 64 bytes, the argument will be implicitly truncated.Use div64_u64() instead of div_u64() so that the value used in the isthis a safe division check is the same as the divisor.Also, remove redundant cast of the numerator to u64, as that should happenimplicitly.This would be difficult to exploit in memcg domain, given the ratio-basedarithmetic domain_drity_limits() uses, but is much easier in globalwriteback domain with a BDI_CAP_STRICTLIMIT-backing device, using e.g. vm.dirty_bytes=(1<<32)*PAGE_SIZE so that dtc->thresh == (1<<32)
openEuler评分：
5.5
Vector：CVSS：2.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
受影响版本排查(受影响/不受影响)：
1.openEuler-20.03-LTS-SP1(4.19.90):受影响
2.openEuler-20.03-LTS-SP4(4.19.90):受影响
3.openEuler-22.03-LTS(5.10.0):受影响
4.openEuler-22.03-LTS-SP1(5.10.0):受影响
5.openEuler-22.03-LTS-SP2(5.10.0):受影响
6.openEuler-22.03-LTS-SP3(5.10.0):受影响
7.master(6.1.0):不受影响
8.openEuler-22.03-LTS-Next(5.10.0):不受影响
9.openEuler-24.03-LTS:不受影响
10.openEuler-24.03-LTS-Next:不受影响

修复是否涉及abi变化(是/否)：
1.openEuler-20.03-LTS-SP1(4.19.90):否
2.openEuler-20.03-LTS-SP4(4.19.90):否
3.openEuler-22.03-LTS(5.10.0):否
4.openEuler-22.03-LTS-SP1(5.10.0):否
5.openEuler-22.03-LTS-SP2(5.10.0):否
6.openEuler-22.03-LTS-SP3(5.10.0):否
7.master(6.1.0):否
8.openEuler-22.03-LTS-Next(5.10.0):否
9.openEuler-24.03-LTS:否
10.openEuler-24.03-LTS-Next:否

三、漏洞修复
安全公告链接：https://www.openeuler.org/zh/security/safety-bulletin/detail/?id=openEuler-SA-2024-1649