In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
LoongArch: Avoid preempt count underflow without probe<\/p>\n
LoongArch uses break 11 for the breakpoint placed after an instruction
\nthat Kprobes executes out of line. Since userspace can issue the same
\nbreak instruction, do_bp() can reach kprobe_singlestep_handler() when
\nthere is no current probe.<\/p>\n
The handler actually returns false in this case, but it first calls
\npreempt_enable_no_resched(). The corresponding preempt_disable() is done
\nby kprobe_breakpoint_handler() on a real Kprobe hit, so it has not run
\nhere. As a result, an ordinary userspace breakpoint (code 11) underflows
\nthe current task’s preempt count.<\/p>\n
This also makes in_interrupt() return true until the task schedules. One
\nvisible consequence is the socket cgroup attribution: cgroup_sk_alloc()
\ntreats the allocation as interrupt context and assigns the socket to the
\nroot cgroup. A socket opened from the SIGTRAP handler can then avoid a
\nBPF_CGROUP_INET_SOCK_CREATE policy attached to the task’s own cgroup.<\/p>\n
Return as soon as kprobe_running() reports no active probe.<\/p>\n
The same check has appeared in [PATCH v10 2\/4] of the original LoongArch
\nKprobes series, but was dropped before the feature reached mainline.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
LoongArch: Avoid preempt count underflow without probe<\/p>\n
LoongArch uses break 11 for the breakpoint placed after an instruction
\nthat<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-24589","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/24589","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=24589"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=24589"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=24589"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}