In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size<\/p>\n
smb_check_perm_dacl() validates that the DACL fits inside the NT
\nsecurity descriptor, but then bounds its two ACE walks by the
\nremaining NTSD length (acl_size) rather than the DACL’s declared
\nsize (pdacl_size).<\/p>\n
When pdacl->size is smaller than the trailing NTSD buffer, bytes
\nafter the declared DACL boundary – still inside the stored security
\ndescriptor – are parsed as ACEs during access checks. A crafted
\nDACL can place an access-granting ACE beyond pdacl->size, and the
\ncurrent code accepts it during SMB2_CREATE access validation, while
\nparse_dacl() and smb_inherit_dacl() stop at pdacl_size.<\/p>\n
Bound both ACE walks by pdacl_size to match the DACL boundary
\nsemantics used elsewhere in the server.<\/p>\n
Validation:
\n– semantic KUnit harness shows the post-boundary ACE is selected
\n before the fix and rejected (EACCES) after it
\n– linux master (7.2-rc6), x86_64<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size<\/p>\n
smb_check_perm_dacl() validates that the DACL fits inside the NT
\nsecurit<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-25562","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/25562","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=25562"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=25562"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=25562"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}