In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
NFS: Return a delegation the client fails to record<\/p>\n
When an NFS server grants a delegation in an OPEN reply,
\nnfs_inode_set_delegation() records it on the client. However, three
\nof its error flows return without sending DELEGRETURN.<\/p>\n
A delegation can be relinquished only by DELEGRETURN (RFC 8881
\nSection 20.2.4), so dropping one silently leaves the server believing
\nthe client still holds it. If the server happens to recall that
\ndelegation, the client answers CB_RECALL with NFS4ERR_BADHANDLE
\nbecause it has no record of the stateid. The server revokes the
\ndelegation and moves it onto its cl_revoked list, because the client
\nnever sends the FREE_STATEID that would drain it. Every subsequent
\nSEQUENCE reply then carries SEQ4_STATUS_RECALLABLE_STATE_REVOKED,
\nand the client’s state manager loops issuing TEST_STATEID across its
\ndelegations without ever clearing the condition.<\/p>\n
The window is easy to reach now that a server offers a write
\ndelegation on any write OPEN: a delegation recalled for one opener
\nraces a re-open that the server answers with a fresh write
\ndelegation.<\/p>\n
Instead of dropping it, hand the delegation back during these error
\nflows.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
NFS: Return a delegation the client fails to record<\/p>\n
When an NFS server grants a delegation in an OPEN reply,
\nnfs_inode_set_delegat<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-25643","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/25643","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=25643"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=25643"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=25643"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}