In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check<\/p>\n
The header for commit e75b23f9e323 (“nfsd: check d_can_lookup in
\nfh_verify of directories”) details the assumption that justified
\nadding the WARN_ON_ONCE to nfsd_mode_check(), that assumption is
\ninvalid (in the case of NFS reexport).<\/p>\n
When NFSD exports an NFS filesystem it is very possible for
\nnfsd_mode_check() to encounter a @dentry that doesn’t have
\ni_op->lookup (see nfs_fhget()’s NFS_ATTR_FATTR_MOUNTPOINT and
\nNFS_ATTR_FATTR_V4_REFERRAL handling, and d_flags_for_inode()).<\/p>\n
So remove nfsd_mode_check()’s WARN_ON_ONCE(). The nfserr_notdir
\nreturn on that branch must stay. It guards the subsequent
\nlookup_one_unlocked() -> __lookup_slow() path, which calls
\ninode->i_op->lookup() with no NULL check, so returning nfserr_notdir
\nis what keeps a client LOOKUP into such a @dentry from dereferencing
\na NULL method pointer.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check<\/p>\n
The header for commit e75b23f9e323 (“nfsd: check d_can_lookup in
\nfh_verify o<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-21633","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/21633","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=21633"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21633"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21633"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}