In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
net: microchip: vcap: fix races on the shared Super VCAP block<\/p>\n
The VCAP instances on a chip are not independent, yet they are locked
\nindependently. On sparx5 and lan969x the IS0 and IS2 instances are
\nbacked by the same Super VCAP hardware block and share its cache and
\ncommand registers: every access drives the shared VCAP_SUPER_CTRL
\nregister and moves data through the shared cache registers.<\/p>\n
Accessing one instance therefore races with accessing another. The
\nper-instance admin->lock cannot prevent this, as each instance takes a
\ndifferent lock.<\/p>\n
The locking issue is mostly disguised by the fact that the core usage of
\nthe vcap api runs under rtnl. However, the full rule dump in debugfs
\ndecodes rules straight from hardware (a READ command followed by a cache
\nread) and runs outside rtnl, so it races a concurrent tc-flower rule
\nwrite to another Super VCAP instance.<\/p>\n
Besides corrupting the dump, the read repopulates the shared cache
\nbetween the writers cache fill and its write command, so the writer
\ncommits the wrong data and corrupts the hardware entry.<\/p>\n
Introduce vcap_lock() and vcap_unlock() helpers and route every rule
\nlock site in the VCAP API and its debugfs code through them. Replace the
\nper-instance admin->lock with a single mutex in struct vcap_control that
\nserializes access to all instances. The helpers reach it through a new
\nadmin->vctrl back-pointer, and the clients initialise and destroy the
\ncontrol lock instead of a per-instance one.<\/p>\n
No path holds more than one instance lock, so collapsing them onto a
\nsingle mutex cannot self-deadlock.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
net: microchip: vcap: fix races on the shared Super VCAP block<\/p>\n
The VCAP instances on a chip are not independent, yet they are lock<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-6967","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/6967","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=6967"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6967"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6967"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}