In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
ksmbd: fix maximum allowed access checks<\/p>\n
The DACL permission check looks for an ACE matching the current user and
\nfalls back to the Everyone ACE. It does not consider an Authenticated
\nUsers ACE, even though an authenticated session is a member of that
\nwell-known group.<\/p>\n
As a result, opening a file whose access is granted through S-1-5-11 can
\nincorrectly fail with STATUS_ACCESS_DENIED. Treat an Authenticated Users
\nACE as a fallback entry alongside Everyone.<\/p>\n
The maximal access calculation also combines access masks from every ACE,
\nregardless of whether its SID applies to the current user. This can grant
\nrights belonging to an unrelated principal. Process only ACEs applying to
\nthe user, Everyone, or Authenticated Users, and accumulate allowed and
\ndenied masks in ACL order. Preserve explicitly requested access bits so
\nthey are validated against the resulting maximal mask.<\/p>\n
When ACCESS_SYSTEM_SECURITY is denied, report STATUS_PRIVILEGE_NOT_HELD
\ninstead of the generic STATUS_ACCESS_DENIED. Access to the system ACL
\nrequires a security privilege that ksmbd does not grant.<\/p>\n
For regular files, include FILE_EXECUTE in maximal access when the client
\nrequested GENERIC_EXECUTE and the DACL grants the complete file-read set.
\nKeep a direct FILE_EXECUTE request subject to the explicit DACL bit. This
\nmatches the POSIX file ACL mapping without broadening specific execute
\nrequests.<\/p>\n
Do not replace rights from an applicable NT ACE with a POSIX ACL entry.
\nThe POSIX ACL is only a fallback when no user, Everyone, or Authenticated
\nUsers ACE applies; otherwise it can incorrectly broaden the stored DACL.<\/p>\n
This fixes smb2.maximum_allowed.maximum_allowed.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
ksmbd: fix maximum allowed access checks<\/p>\n
The DACL permission check looks for an ACE matching the current user and
\nfalls back to th<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-28546","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/28546","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=28546"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=28546"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=28546"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}