In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
smb: client: drain and invalidate before server-side copy\/clone<\/p>\n
cifs_file_copychunk_range() and the clone (FICLONE) path of
\ncifs_remap_file_range() do not serialise the destination page cache
\nagainst the server-side copy the way the other server-side range
\noperations (smb3_zero_range(), smb3_punch_hole(), smb3_collapse_range()
\nand smb3_insert_range()) do.<\/p>\n
cifs_file_copychunk_range() invalidates the destination range with
\nfilemap_invalidate_inode(), which takes and drops the mapping’s
\ninvalidate_lock internally, so the lock is no longer held when the
\ncopychunk ioctl is issued. It also never drains in-flight netfs I\/O on
\nthe target. The clone path never takes the invalidate_lock at all (only
\ni_rwsem), uses a bare truncate_inode_pages_range() and likewise does not
\ndrain outstanding I\/O.<\/p>\n
As a result an asynchronous destination writeback can complete after the
\nserver-side copy\/clone has run and reinstate stale data over the region
\njust written by the server, corrupting the file. This is the same class
\nof corruption as commit d7d2adcd022b (“smb\/client: flush dirty data
\nbefore punching a hole”) and has been seen randomly in generic\/363
\nagainst Windows Server.<\/p>\n
Fix both paths to follow the established ordering: hold the target
\nmapping’s invalidate_lock across the flush and invalidation of the
\ndestination and the server ioctl, and call netfs_wait_for_outstanding_io()
\non the target to drain in-flight writes before the ioctl is issued. Only
\nthe target inode’s invalidate_lock is required, as the source is merely
\nflushed and not invalidated; i_rwsem (already held via
\nlock_two_nondirectories()) is acquired before the invalidate_lock,
\nmatching the VFS lock ordering. Since filemap_invalidate_inode() takes
\nthat same lock internally, replace it with its own unmap\/flush\/invalidate
\nsteps instead of calling it, and return early on a zero-length copy to
\navoid a range underflow.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
smb: client: drain and invalidate before server-side copy\/clone<\/p>\n
cifs_file_copychunk_range() and the clone (FICLONE) path of
\ncifs_r<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-41154","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/41154","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=41154"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=41154"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=41154"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}