diff options
| author | Chuck Lever <chuck.lever@oracle.com> | 2021-12-21 11:52:06 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-08 19:12:33 +0100 |
| commit | 384d1b11382b4d8065a1c3ce930e88c5193f9857 (patch) | |
| tree | 0892c035814b483222cdf6631ee41f83f25f78a1 /fs/nfsd/nfsproc.c | |
| parent | 2de88544b3dbe9f4be3220750e34c97dd86386c1 (diff) | |
| download | linux-stable-384d1b11382b4d8065a1c3ce930e88c5193f9857.tar.gz linux-stable-384d1b11382b4d8065a1c3ce930e88c5193f9857.tar.bz2 linux-stable-384d1b11382b4d8065a1c3ce930e88c5193f9857.zip | |
NFSD: Fix zero-length NFSv3 WRITEs
[ Upstream commit 6a2f774424bfdcc2df3e17de0cefe74a4269cad5 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs/nfsd/nfsproc.c')
| -rw-r--r-- | fs/nfsd/nfsproc.c | 5 |
1 files changed, 0 insertions, 5 deletions
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c index de282f3273c5..312fd289be58 100644 --- a/fs/nfsd/nfsproc.c +++ b/fs/nfsd/nfsproc.c @@ -235,10 +235,6 @@ nfsd_proc_write(struct svc_rqst *rqstp) argp->len, argp->offset); nvecs = svc_fill_write_vector(rqstp, &argp->payload); - if (!nvecs) { - resp->status = nfserr_io; - goto out; - } resp->status = nfsd_write(rqstp, fh_copy(&resp->fh, &argp->fh), argp->offset, rqstp->rq_vec, nvecs, @@ -247,7 +243,6 @@ nfsd_proc_write(struct svc_rqst *rqstp) resp->status = fh_getattr(&resp->fh, &resp->stat); else if (resp->status == nfserr_jukebox) return rpc_drop_reply; -out: return rpc_success; } |