In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
KVM: arm64: Handle negative S1 walk levels in VNCR TLB size evaluation<\/p>\n
Computing the effects of a TLB invalidation involves looking at
\nthe size of the mapping cached by the TLB. For S1 mappings such as
\nVNCR, this is deducted from the combination of the base granule size
\nand the mapping level.<\/p>\n
However, this implies that the S1 MMU is *on*. When the MMU is off,
\nwe indicate this with the level being set to a “creative” value of
\n-127 (S1_MMU_DISABLED).<\/p>\n
This ends-up being misinterpreted by pgshift_level_to_ttl() as it
\ndoesn’t handle negative levels at all (the level is immediately cast
\nto a u8 and only the bottom two bits considered), leading to an
\ninvalidation size of 0. Not helpful.<\/p>\n
Tidy-up pgshift_level_to_ttl() to handle these negative levels, and
\nttl_to_size() to always return SZ_1G when no valid TTL is present.
\nThis allows the removal of open-coded checks for similar situations.<\/p>\n
Note that the check for a negative value not explicitely checking for
\nS1_MMU_DISABLED is deliberate, so that actual negative levels introduced
\nwith LVA2 and D128 can take the same path if we ever support them.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
KVM: arm64: Handle negative S1 walk levels in VNCR TLB size evaluation<\/p>\n
Computing the effects of a TLB invalidation involves lookin<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-24432","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/24432","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=24432"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=24432"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=24432"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}