In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
fhandle: reject detached mounts in capable_wrt_mount()<\/p>\n
The recent fhandle RCU fix moved the mount namespace capability check
\ninto capable_wrt_mount(), so a non-NULL mnt_namespace survives the
\nns_capable() dereference. The helper still assumes the later
\nREAD_ONCE(mount->mnt_ns) must be non-NULL because may_decode_fh()
\nchecked is_mounted() first.<\/p>\n
That assumption is not stable. A detached mount from
\nopen_tree(…, OPEN_TREE_CLONE) can be dissolved on fput while
\nopen_by_handle_at() is between those checks, and umount_tree() can
\nclear mount->mnt_ns. If the helper observes NULL, it dereferences
\nmnt_ns->user_ns and panics.<\/p>\n
Return false when the RCU read observes a detached mount. This keeps
\nthe relaxed permission path conservative: a mount no longer attached
\nto a namespace cannot authorize open_by_handle_at() access.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
fhandle: reject detached mounts in capable_wrt_mount()<\/p>\n
The recent fhandle RCU fix moved the mount namespace capability check
\ninto <\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-6738","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/6738","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=6738"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6738"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6738"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}