一、漏洞信息
漏洞编号：CVE-2024-26885
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 V3.0分值：
BaseScore：7.8 High
Vector：CVSS：3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
漏洞简述：
In the Linux kernel, the following vulnerability has been resolved:bpf: Fix DEVMAP_HASH overflow check on 32-bit archesThe devmap code allocates a number hash buckets equal to the next powerof two of the max_entries value provided when creating the map. Whenrounding up to the next power of two, the 32-bit variable storing thenumber of buckets can overflow, and the code checks for overflow bychecking if the truncated 32-bit value is equal to 0. However, on 32-bitarches the rounding up itself can overflow mid-way through, because itends up doing a left-shift of 32 bits on an unsigned long value. If thesize of an unsigned long is four bytes, this is undefined behaviour, sothere is no guarantee that we ll end up with a nice and tidy 0-value atthe end.Syzbot managed to turn this into a crash on arm32 by creating aDEVMAP_HASH with max_entries > 0x80000000 and then trying to update it.Fix this by moving the overflow check to before the rounding upoperation.
漏洞公开时间：2024-04-17 19:15:10
漏洞创建时间：2024-04-17 20:05:16
漏洞详情参考链接：
https://nvd.nist.gov/vuln/detail/CVE-2024-26885

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:bpf: Fix DEVMAP_HASH overflow check on 32-bit archesThe devmap code allocates a number hash buckets equal to the next powerof two of the max_entries value provided when creating the map. Whenrounding up to the next power of two, the 32-bit variable storing thenumber of buckets can overflow, and the code checks for overflow bychecking if the truncated 32-bit value is equal to 0. However, on 32-bitarches the rounding up itself can overflow mid-way through, because itends up doing a left-shift of 32 bits on an unsigned long value. If thesize of an unsigned long is four bytes, this is undefined behaviour, sothere is no guarantee that we ll end up with a nice and tidy 0-value atthe end.Syzbot managed to turn this into a crash on arm32 by creating aDEVMAP_HASH with max_entries > 0x80000000 and then trying to update it.Fix this by moving the overflow check to before the rounding upoperation.
openEuler评分：
7.8
Vector：CVSS：3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
受影响版本排查(受影响/不受影响)：
1.openEuler-22.03-LTS(5.10.0):受影响
2.openEuler-22.03-LTS-SP1(5.10.0):受影响
3.openEuler-22.03-LTS-SP2(5.10.0):受影响
4.openEuler-22.03-LTS-SP3(5.10.0):受影响
5.openEuler-20.03-LTS-SP1(4.19.90):不受影响
6.openEuler-20.03-LTS-SP4(4.19.90):不受影响
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-HotPatchSA-2024-1012