In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
ext4: don’t enable DAX on new encrypted files<\/p>\n
Currently, when a new encrypted regular file is created, the call to
\next4_set_inode_flags(inode, init=true) in __ext4_new_inode() is made
\nbefore EXT4_INODE_ENCRYPT is set. As a result, it can set S_DAX if the
\nfilesystem is mounted with “-o dax=always”.<\/p>\n
EXT4_INODE_ENCRYPT then actually gets set a bit later in
\n__ext4_new_inode(), when it calls fscrypt_set_context() which calls
\next4_set_context(). ext4_set_context() sets EXT4_INODE_ENCRYPT and
\ncalls ext4_set_inode_flags(inode, init=false) to set S_ENCRYPTED too.<\/p>\n
This was intended to clear S_DAX as well. However, this was broken by
\ncommit 043546e46dc7 (“fs\/ext4: Only change S_DAX on inode load”). This
\ncauses data written to the file to bypass encryption, also causing
\nxfstests failures such as generic\/548 (when “-o dax=always” is used).<\/p>\n
Fix this by simplifying the flow by making __ext4_new_inode() set
\nEXT4_INODE_ENCRYPT earlier. This makes it take effect in
\next4_set_inode_flags(inode, init=true), making S_DAX never be set.<\/p>\n
Similarly, make EXT4_STATE_MAY_INLINE_DATA never be set in the first
\nplace on new encrypted inodes. Then it doesn’t need to be cleared.<\/p>\n
As a result of these simplifications, ext4_set_context() no longer needs
\nto change inode flags or state when ‘handle != NULL’. Remove that too.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
ext4: don’t enable DAX on new encrypted files<\/p>\n
Currently, when a new encrypted regular file is created, the call to
\next4_set_inode_<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-17310","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/17310","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=17310"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=17310"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=17310"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}