In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
cpufreq: zero-initialize policy cpumask before sysfs publication<\/p>\n
cpufreq_policy_alloc() allocates policy->cpus with alloc_cpumask_var(),
\ni.e. without __GFP_ZERO, unlike the sibling related_cpus and real_cpus
\nmasks. With CONFIG_CPUMASK_OFFSTACK=y the mask is a separate
\nkmalloc_node() allocation, so its bitmap holds whatever the slab allocator
\nleft behind:<\/p>\n
cpufreq_online()
\n cpufreq_policy_alloc()
\n alloc_cpumask_var(&policy->cpus) \/* bitmap is uninitialized *\/
\n kobject_init_and_add() \/* policy%u\/ appears in sysfs *\/
\n cpufreq_policy_online()
\n cpumask_copy(policy->cpus, cpumask_of(cpu)) \/* first valid value *\/<\/p>\n
This leaves a window in which the sysfs attributes are already reachable
\nwhile policy->cpus is still garbage. show()\/store() gate on
\npolicy_is_inactive(), i.e. cpumask_empty(policy->cpus), so a non-zero
\nbitmap makes them run the attribute callbacks on a policy that is not
\ninitialized yet.<\/p>\n
Fix this by using zalloc_cpumask_var() for policy->cpus.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
cpufreq: zero-initialize policy cpumask before sysfs publication<\/p>\n
cpufreq_policy_alloc() allocates policy->cpus with alloc_cpumask_<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-29061","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/29061","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=29061"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=29061"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=29061"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}