An NFS operation that creates a new symlink includes the symlink data,
which is xdr-encoded as a length followed by the data plus 0 to 3 bytes
of zero-padding as required to reach a 4-byte boundary.
The vfs, on the other hand, wants null-terminated data.
The simple way to handle this would be by copying the data into a newly
allocated buffer with space for the final null.
The current nfsd_symlink code tries to be more clever by skipping that
step in the (likely) case where the byte following the string is already
0.
But that assumes that the byte following the string is ours to look at.
In fact, it might be the first byte of a page that we can't read, or of
some object that another task might modify.
Worse, the NFSv4 code tries to fix the problem by actually writing to
that byte.
In the NFSv2/v3 cases this actually appears to be safe:
- nfs3svc_decode_symlinkargs explicitly null-terminates the data
(after first checking its length and copying it to a new
page).
- NFSv2 limits symlinks to 1k. The buffer holding the rpc
request is always at least a page, and the link data (and
previous fields) have maximum lengths that prevent the request
from reaching the end of a page.
In the NFSv4 case the CREATE op is potentially just one part of a long
compound so can end up on the end of a page if you're unlucky.
The minimal fix here is to copy and null-terminate in the NFSv4 case.
The nfsd_symlink() interface here seems too fragile, though. It should
really either do the copy itself every time or just require a
null-terminated string.
Reported-by: Jeff Layton <jlayton@primarydata.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The rpc code makes available to the NFS server an array of pages to
encod into. The server represents its reply as an xdr buf, with the
head pointing into the first page in that array, the pages ** array
starting just after that, and the tail (if any) sharing any leftover
space in the page used by the head.
While encoding, we use xdr_stream->page_ptr to keep track of which page
we're currently using.
Currently we set xdr_stream->page_ptr to buf->pages, which makes the
head a weird exception to the rule that page_ptr always points to the
page we're currently encoding into. So, instead set it to buf->pages -
1 (the page actually containing the head), and remove the need for a
little unintuitive logic in xdr_get_next_encode_buffer() and
xdr_truncate_encode.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The memset of resp in svc_process_common should ensure that these are
already zeroed by the time they get here.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
In the NFS4_OPEN_CLAIM_PREVIOUS case, we should only mark it confirmed
if the nfs4_check_open_reclaim check succeeds.
In the NFS4_OPEN_CLAIM_DELEG_PREV_FH and NFS4_OPEN_CLAIM_DELEGATE_PREV
cases, I see no point in declaring the openowner confirmed when the
operation is going to fail anyway, and doing so might allow the client
to game things such that it wouldn't need to confirm a subsequent open
with the same owner.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
RPC_MAX_AUTH_SIZE is scattered around several places. Better to set it
once in the auth code, where this kind of estimate should be made. And
while we're at it we can leave it zero when we're not using krb5i or
krb5p.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
We plan to use this estimate to decide whether or not to allow zero-copy
reads. Currently we're assuming all getattr's are a page, which can be
both too small (ACLs e.g. may be arbitrarily long) and too large (after
an upcoming read patch this will unnecessarily prevent zero copy reads
in any read compound also containing a getattr).
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Currently we limit readdir results to a single page. This can result in
a performance regression compared to NFSv3 when reading large
directories.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
It will turn out to be useful to have a more accurate estimate of reply
size; so, piggyback on the existing op reply-size estimators.
Also move nfsd4_max_reply to nfs4proc.c to get easier access to struct
nfsd4_operation and friends. (Thanks to Christoph Hellwig for pointing
out that simplification.)
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
I ran into this corner case in testing: in theory clients can provide
state owners up to 1024 bytes long. In the sessions case there might be
a risk of this pushing us over the DRC slot size.
The conflicting owner isn't really that important, so let's humor a
client that provides a small maxresponsize_cached by allowing ourselves
to return without the conflicting owner instead of outright failing the
operation.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
After this we can handle for example getattr of very large ACLs.
Read, readdir, readlink are still special cases with their own limits.
Also we can't handle a new operation starting close to the end of a
page.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Now that all op encoders can handle running out of space, we no longer
need to check the remaining size for every operation; only nonidempotent
operations need that check, and that can be done by
nfsd4_check_resp_size.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
We've tried to prevent running out of space with COMPOUND_SLACK_SPACE
and special checking in those operations (getattr) whose result can vary
enormously.
However:
- COMPOUND_SLACK_SPACE may be difficult to maintain as we add
more protocol.
- BUG_ON or page faulting on failure seems overly fragile.
- Especially in the 4.1 case, we prefer not to fail compounds
just because the returned result came *close* to session
limits. (Though perfect enforcement here may be difficult.)
- I'd prefer encoding to be uniform for all encoders instead of
having special exceptions for encoders containing, for
example, attributes.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This is a cosmetic change for now; no change in behavior.
Note we're just depending on xdr_reserve_space to do the bounds checking
for us, we're not really depending on its adjustment of iovec or xdr_buf
lengths yet, as those are fixed up by as necessary after the fact by
read-link operations and by nfs4svc_encode_compoundres. However we do
have to update xdr->iov on read-like operations to prevent
xdr_reserve_space from messing with the already-fixed-up length of the
the head.
When the attribute encoding fails partway through we have to undo the
length adjustments made so far. We do it manually for now, but later
patches will add an xdr_truncate_encode() helper to handle cases like
this.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
If nfsd4_check_resp_size() returns an error then we should really be
truncating the reply here, otherwise we may leave extra garbage at the
end of the rpc reply.
Also add a warning to catch any cases where our reply-size estimates may
be wrong in the case of a non-idempotent operation.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Currently if the nfs-level part of a reply would be too large, we'll
return an error to the client. But if the nfs-level part fits and
leaves no room for krb5p or krb5i stuff, then we just drop the request
entirely.
That's no good. Instead, reserve some slack space at the end of the
buffer and make sure we fail outright if we'd come close.
The slack space here is a massive overstimate of what's required, we
should probably try for a tighter limit at some point.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Just change the nfsd4_encode_getattr api. Not changing any code or
adding any new functionality yet.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This is a mechanical transformation with no change in behavior.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Currently a non-idempotent op reply may be cached if it fails in the
proc code but not if it fails at xdr decoding. I doubt there are any
xdr-decoding-time errors that would make this a problem in practice, so
this probably isn't a serious bug.
The space estimates should also take into account space required for
encoding of error returns. Again, not a practical problem, though it
would become one after future patches which will tighten the space
estimates.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
OP_MODIFIES_SOMETHING flags operations that we should be careful not to
initiate without being sure we have the buffer space to encode a reply.
None of these ops fall into that category.
We could probably remove a few more, but this isn't a very important
problem at least for ops whose reply size is easy to estimate.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Move the state locking and file descriptor reference out from the
callers and into nfs4_preprocess_stateid_op() itself.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Testing NFS4.0 by pynfs, I got some messeages as,
"nfsd: inode locked twice during operation."
When one compound RPC contains two or more ops that locks
the filehandle,the second op will cause the message.
As two SETATTR ops, after the first SETATTR, nfsd will not call
fh_put() to release current filehandle, it means filehandle have
unlocked with fh_post_saved = 1.
The second SETATTR find fh_post_saved = 1, and printk the message.
v2: introduce helper fh_clear_wcc().
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Pull nfsd updates from Bruce Fields:
- Handle some loose ends from the vfs read delegation support.
(For example nfsd can stop breaking leases on its own in a
fewer places where it can now depend on the vfs to.)
- Make life a little easier for NFSv4-only configurations
(thanks to Kinglong Mee).
- Fix some gss-proxy problems (thanks Jeff Layton).
- miscellaneous bug fixes and cleanup
* 'for-3.14' of git://linux-nfs.org/~bfields/linux: (38 commits)
nfsd: consider CLAIM_FH when handing out delegation
nfsd4: fix delegation-unlink/rename race
nfsd4: delay setting current_fh in open
nfsd4: minor nfs4_setlease cleanup
gss_krb5: use lcm from kernel lib
nfsd4: decrease nfsd4_encode_fattr stack usage
nfsd: fix encode_entryplus_baggage stack usage
nfsd4: simplify xdr encoding of nfsv4 names
nfsd4: encode_rdattr_error cleanup
nfsd4: nfsd4_encode_fattr cleanup
minor svcauth_gss.c cleanup
nfsd4: better VERIFY comment
nfsd4: break only delegations when appropriate
NFSD: Fix a memory leak in nfsd4_create_session
sunrpc: get rid of use_gssp_lock
sunrpc: fix potential race between setting use_gss_proxy and the upcall rpc_clnt
sunrpc: don't wait for write before allowing reads from use-gss-proxy file
nfsd: get rid of unused function definition
Define op_iattr for nfsd4_open instead using macro
NFSD: fix compile warning without CONFIG_NFSD_V3
...
If a file is unlinked or renamed between the time when we do the local
open and the time when we get the delegation, then we will return to the
client indicating that it holds a delegation even though the file no
longer exists under the name it was open under.
But a client performing an open-by-name, when it is returned a
delegation, must be able to assume that the file is still linked at the
name it was opened under.
So, hold the parent i_mutex for longer to prevent concurrent renames or
unlinks.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This is basically a no-op, to simplify a following patch.
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Remove the boilerplate code to marshall and unmarhall ACL objects into
xattrs and operate on the posix_acl objects directly. Also move all
the ACL handling code into nfs?acl.c where it belongs.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
NFSv4 clients can contact port 2049 directly instead of needing the
portmapper.
Therefore a failure to register to the portmapper when starting an
NFSv4-only server isn't really a problem.
But Gareth Williams reports that an attempt to start an NFSv4-only
server without starting portmap fails:
#rpc.nfsd -N 2 -N 3
rpc.nfsd: writing fd to kernel failed: errno 111 (Connection refused)
rpc.nfsd: unable to set any sockets for nfsd
Add a flag to svc_version to tell the rpc layer it can safely ignore an
rpcbind failure in the NFSv4-only case.
Reported-by: Gareth Williams <gareth@garethwilliams.me.uk>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
commit 58cd57bfd9
"nfsd: Fix SP4_MACH_CRED negotiation in EXCHANGE_ID"
miss calculating the length of bitmap for spo_must_enforce and spo_must_allow.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
- don't BUG_ON() when not SP4_NONE
- calculate recv and send reserve sizes correctly
Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
You can turn on or off support for minorversions using e.g.
echo "-4.2" >/proc/fs/nfsd/versions
However, the current implementation is a little wonky. For example, the
above will turn off 4.2 support, but it will also turn *on* 4.1 support.
This didn't matter as long as we only had 2 minorversions, which was
true till very recently.
And do a little cleanup here.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
We saw a v4.0 client's create fail as follows:
- open create succeeds and gets a read delegation
- client attempts to set mode on new file, gets DELAY while
server recalls delegation.
- client attempts a CLAIM_DELEGATE_CUR open using the
delegation, gets error because of new file mode.
This probably can't happen on a recent kernel since we're no longer
giving out delegations on create opens. Nevertheless, it's a
bug--reclaim opens should bypass permission checks.
Reported-by: Steve Dickson <steved@redhat.com>
Reported-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Implement labeled NFS on the server: encoding and decoding, and writing
and reading, of file labels.
Enabled with CONFIG_NFSD_V4_SECURITY_LABEL.
Signed-off-by: Matthew N. Dodd <Matthew.Dodd@sparta.com>
Signed-off-by: Miguel Rodel Felipe <Rodel_FM@dsi.a-star.edu.sg>
Signed-off-by: Phua Eu Gene <PHUA_Eu_Gene@dsi.a-star.edu.sg>
Signed-off-by: Khin Mi Mi Aung <Mi_Mi_AUNG@dsi.a-star.edu.sg>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The Linux client is using CLAIM_FH to implement regular opens, not just
recovery cases, so it depends on the server to check permissions
correctly.
Therefore the owner override, which may make sense in the delegation
recovery case, isn't right in the CLAIM_FH case.
Symptoms: on a client with 49f9a0fafd
"NFSv4.1: Enable open-by-filehandle", Bryan noticed this:
touch test.txt
chmod 000 test.txt
echo test > test.txt
succeeding.
Cc: stable@kernel.org
Reported-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
We're going out of our way here to remap an error to make rfc 3530
happy--but the rfc itself (nor rfc 1813, which has similar language)
gives no justification. And disagrees with local filesystem behavior,
with Linux and posix man pages, and knfsd's implemented behavior for v2
and v3.
And the documented behavior seems better, in that it gives a little more
information--you could implement the 3530 behavior using the posix
behavior, but not the other way around.
Also, the Linux client makes no attempt to remap this error in the v4
case, so it can end up just returning EEXIST to the application in a
case where it should return EISDIR.
So honestly I think the rfc's are just buggy here--or in any case it
doesn't see worth the trouble to remap this error.
Reported-by: Frank S Filz <ffilz@us.ibm.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Closed stateid's are kept around a little while to handle close replays
in the 4.0 case. So we stash them in the last-used stateid in the
oo_last_closed_stateid field of the open owner. We can free that in
encode_seqid_op_tail once the seqid on the open owner is next
incremented. But we don't want to do that on the close itself; so we
set NFS4_OO_PURGE_CLOSE flag set on the open owner, skip freeing it the
first time through encode_seqid_op_tail, then when we see that flag set
next time we free it.
This is unnecessarily baroque.
Instead, just move the logic that increments the seqid out of the xdr
code and into the operation code itself.
The justification given for the current placement is that we need to
wait till the last minute to be sure we know whether the status is a
sequence-id-mutating error or not, but examination of the code shows
that can't actually happen.
Reported-by: Yanchuan Nian <ycnian@gmail.com>
Tested-by: Yanchuan Nian <ycnian@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
we should return error status directly when nfs4_preprocess_stateid_op
return error.
Signed-off-by: fanchaoting <fanchaoting@cn.fujitsu.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
If a client sets an owner (or group_owner or acl) attribute on open for
create, and the mapping of that owner to an id fails, then we return
BAD_OWNER. But BAD_OWNER is a seqid-mutating error, so we can't
shortcut the open processing that case: we have to at least look up the
owner so we can find the seqid to bump.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This BUG_ON just crashes the thread a little earlier than it would
otherwise--it doesn't seem useful.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
J. Bruce Fields