In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
KVM: arm64: Handle VNCR TLB invalidation race with vcpu_put() VNCR unmapping<\/p>\n
While VNCR TLB invalidation always occurs under the MMU lock,
\nvcpu_put() doesn’t, while it unmaps the VNCR page.<\/p>\n
The problem is that the invalidation evaluates vncr_tlb::cpu to
\ndecide whether an unmapping needs to take place (cpu != -1) before
\nperforming it. On the other hand, this_cpu_reset_vncr_fixmap()
\nunconditionally unmaps if L1_VNCR_MAPPED is set.<\/p>\n
These two obviously can race, with a TOCTOU pattern on the TLBI
\npath, and a BUG_ON() on the vcpu_put() path. And the two can end-up
\ncalling vncr_fixmap(-1), with extra lethal effects.<\/p>\n
Move the reset of vncr_tlb::cpu to -1 to a common function, and make
\nthis update atomic so that only a single thread can reset the field
\nand perform the corresponding unmap. The vcpu_put() still need to
\nunconditionally unmap the current VNCR to close another ugly race.<\/p>\n
Finally, the assignment of vncr_tlb::cpu is moved to be kept in sync
\nwith the actual mapping, similar to L1_VNCR_MAPPED being set.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
KVM: arm64: Handle VNCR TLB invalidation race with vcpu_put() VNCR unmapping<\/p>\n
While VNCR TLB invalidation always occurs under the M<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-24604","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/24604","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=24604"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=24604"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=24604"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}