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author | Chuck Lever <chuck.lever@oracle.com> | 2021-12-21 19:52:06 +0300 |
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committer | Chuck Lever <chuck.lever@oracle.com> | 2022-01-08 22:42:01 +0300 |
commit | 6a2f774424bfdcc2df3e17de0cefe74a4269cad5 (patch) | |
tree | 950b7a0ff692a5cb7da12674c93d5463bc2c0407 /Kconfig | |
parent | 47446d74f1707049067fee038507cdffda805631 (diff) | |
download | linux-6a2f774424bfdcc2df3e17de0cefe74a4269cad5.tar.xz |
NFSD: Fix zero-length NFSv3 WRITEs
The Linux NFS server currently responds to a zero-length NFSv3 WRITE
request with NFS3ERR_IO. It responds to a zero-length NFSv4 WRITE
with NFS4_OK and count of zero.
RFC 1813 says of the WRITE procedure's @count argument:
count
The number of bytes of data to be written. If count is
0, the WRITE will succeed and return a count of 0,
barring errors due to permissions checking.
RFC 8881 has similar language for NFSv4, though NFSv4 removed the
explicit @count argument because that value is already contained in
the opaque payload array.
The synthetic client pynfs's WRT4 and WRT15 tests do emit zero-
length WRITEs to exercise this spec requirement. Commit fdec6114ee1f
("nfsd4: zero-length WRITE should succeed") addressed the same
problem there with the same fix.
But interestingly the Linux NFS client does not appear to emit zero-
length WRITEs, instead squelching them. I'm not aware of a test that
can generate such WRITEs for NFSv3, so I wrote a naive C program to
generate a zero-length WRITE and test this fix.
Fixes: 8154ef2776aa ("NFSD: Clean up legacy NFS WRITE argument XDR decoders")
Reported-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'Kconfig')
0 files changed, 0 insertions, 0 deletions