xfrm: Update ipcomp_scratches with NULL when freed 漏洞信息(CVE-2022-50569)

一、漏洞 CVE-2022-50569 基础信息

漏洞信息

                                        # xfrm: 释放时置空ipcomp_scratches

N/A

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漏洞标题

xfrm: Update ipcomp_scratches with NULL when freed

来源：美国国家漏洞数据库 NVD

漏洞描述信息

In the Linux kernel, the following vulnerability has been resolved: xfrm: Update ipcomp_scratches with NULL when freed Currently if ipcomp_alloc_scratches() fails to allocate memory ipcomp_scratches holds obsolete address. So when we try to free the percpu scratches using ipcomp_free_scratches() it tries to vfree non existent vm area. Described below: static void * __percpu *ipcomp_alloc_scratches(void) { ... scratches = alloc_percpu(void *); if (!scratches) return NULL; ipcomp_scratches does not know about this allocation failure. Therefore holding the old obsolete address. ... } So when we free, static void ipcomp_free_scratches(void) { ... scratches = ipcomp_scratches; Assigning obsolete address from ipcomp_scratches if (!scratches) return; for_each_possible_cpu(i) vfree(*per_cpu_ptr(scratches, i)); Trying to free non existent page, causing warning: trying to vfree existent vm area. ... } Fix this breakage by updating ipcomp_scrtches with NULL when scratches is freed

来源：美国国家漏洞数据库 NVD