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    nfsd4: permit read opens of executable-only files · a043226b
    J. Bruce Fields 提交于
    A client that wants to execute a file must be able to read it.  Read
    opens over nfs are therefore implicitly allowed for executable files
    even when those files are not readable.
    
    NFSv2/v3 get this right by using a passed-in NFSD_MAY_OWNER_OVERRIDE on
    read requests, but NFSv4 has gotten this wrong ever since
    dc730e17 "nfsd4: fix owner-override on
    open", when we realized that the file owner shouldn't override
    permissions on non-reclaim NFSv4 opens.
    
    So we can't use NFSD_MAY_OWNER_OVERRIDE to tell nfsd_permission to allow
    reads of executable files.
    
    So, do the same thing we do whenever we encounter another weird NFS
    permission nit: define yet another NFSD_MAY_* flag.
    
    The industry's future standardization on 128-bit processors will be
    motivated primarily by the need for integers with enough bits for all
    the NFSD_MAY_* flags.
    Reported-by: NLeonardo Borda <leonardoborda@gmail.com>
    Cc: stable@kernel.org
    Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
    a043226b
vfs.c 53.7 KB