In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
nfsd: Reset write verifier when async COPY writeback fails<\/p>\n
Async COPY captures nn->writeverf at request time and reports it to
\nthe client via CB_OFFLOAD after the worker kthread completes. When
\nthe post-copy vfs_fsync_range() or filemap_check_wb_err() in
\n_nfsd_copy_file_range() reports an error, the worker correctly
\nleaves NFSD4_COPY_F_COMMITTED clear so that CB_OFFLOAD encodes
\nwr_stable_how as NFS_UNSTABLE, but the server’s write verifier is
\nnot rotated.<\/p>\n
A client that receives NFS_UNSTABLE in CB_OFFLOAD follows up with
\nCOMMIT to make the copied data durable. With the verifier
\nunchanged, COMMIT returns the same value the client just received
\nvia CB_OFFLOAD, and the client concludes the copy is durable —
\nsilently dropping the data whose writeback in fact failed. This
\nviolates the UNSTABLE+COMMIT durability contract (RFC 7862 section
\n15.1, RFC 8881 section 18.32) and matches the bug just fixed in
\nnfsd_vfs_write() and nfsd_commit().<\/p>\n
Rotate nn->writeverf at the writeback-failure site. The async COPY
\nworker has no svc_rqst, so commit_reset_write_verifier() is not
\navailable here; calling nfsd_reset_write_verifier() directly
\nmirrors the trace-less reset already used by
\nnfsd_file_check_write_error() for the same purpose. Filter out
\n-EAGAIN and -ESTALE, matching commit_reset_write_verifier(), since
\nneither indicates a durable-storage failure.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
nfsd: Reset write verifier when async COPY writeback fails<\/p>\n
Async COPY captures nn->writeverf at request time and reports it to
\nthe<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-21628","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/21628","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=21628"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21628"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21628"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}