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2024-03-01nfsd: Fix NFSv3 atomicity bugs in nfsd_setattr()Trond Myklebust
The main point of the guarded SETATTR is to prevent races with other WRITE and SETATTR calls. That requires that the check of the guard time against the inode ctime be done after taking the inode lock. Furthermore, we need to take into account the 32-bit nature of timestamps in NFSv3, and the possibility that files may change at a faster rate than once a second. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: NeilBrown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-30Merge tag 'nfsd-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linuxLinus Torvalds
Pull nfsd updates from Chuck Lever: "This release completes the SunRPC thread scheduler work that was begun in v6.6. The scheduler can now find an svc thread to wake in constant time and without a list walk. Thanks again to Neil Brown for this overhaul. Lorenzo Bianconi contributed infrastructure for a netlink-based NFSD control plane. The long-term plan is to provide the same functionality as found in /proc/fs/nfsd, plus some interesting additions, and then migrate the NFSD user space utilities to netlink. A long series to overhaul NFSD's NFSv4 operation encoding was applied in this release. The goals are to bring this family of encoding functions in line with the matching NFSv4 decoding functions and with the NFSv2 and NFSv3 XDR functions, preparing the way for better memory safety and maintainability. A further improvement to NFSD's write delegation support was contributed by Dai Ngo. This adds a CB_GETATTR callback, enabling the server to retrieve cached size and mtime data from clients holding write delegations. If the server can retrieve this information, it does not have to recall the delegation in some cases. The usual panoply of bug fixes and minor improvements round out this release. As always I am grateful to all contributors, reviewers, and testers" * tag 'nfsd-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: (127 commits) svcrdma: Fix tracepoint printk format svcrdma: Drop connection after an RDMA Read error NFSD: clean up alloc_init_deleg() NFSD: Fix frame size warning in svc_export_parse() NFSD: Rewrite synopsis of nfsd_percpu_counters_init() nfsd: Clean up errors in nfs3proc.c nfsd: Clean up errors in nfs4state.c NFSD: Clean up errors in stats.c NFSD: simplify error paths in nfsd_svc() NFSD: Clean up nfsd4_encode_seek() NFSD: Clean up nfsd4_encode_offset_status() NFSD: Clean up nfsd4_encode_copy_notify() NFSD: Clean up nfsd4_encode_copy() NFSD: Clean up nfsd4_encode_test_stateid() NFSD: Clean up nfsd4_encode_exchange_id() NFSD: Clean up nfsd4_do_encode_secinfo() NFSD: Clean up nfsd4_encode_access() NFSD: Clean up nfsd4_encode_readdir() NFSD: Clean up nfsd4_encode_entry4() NFSD: Add an nfsd4_encode_nfs_cookie4() helper ...
2023-10-18nfsd: convert to new timestamp accessorsJeff Layton
Convert to using the new inode timestamp accessor functions. Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://lore.kernel.org/r/20231004185347.80880-50-jlayton@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-16nfsd: Clean up errors in nfs3proc.cKaiLong Wang
Fix the following errors reported by checkpatch: ERROR: need consistent spacing around '+' (ctx:WxV) ERROR: spaces required around that '?' (ctx:VxW) Signed-off-by: KaiLong Wang <wangkailong@jari.cn> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-08-29nfsd: handle failure to collect pre/post-op attrs more sanelyJeff Layton
Collecting pre_op_attrs can fail, in which case it's probably best to fail the whole operation. Change fh_fill_pre_attrs and fh_fill_both_attrs to return __be32, and have the callers check the return code and abort the operation if it's not nfs_ok. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-06-11NFSD: Hoist rq_vec preparation into nfsd_read()Chuck Lever
Accrue the following benefits: a) Deduplicate this common bit of code. b) Don't prepare rq_vec for NFSv2 and NFSv3 spliced reads, which don't use rq_vec. This is already the case for nfsd4_encode_read(). c) Eventually, converting NFSD's read path to use a bvec iterator will be simpler. In the next patch, nfsd_iter_read() will replace nfsd_readv() for all NFS versions. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-02-22Merge tag 'nfsd-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linuxLinus Torvalds
Pull nfsd updates from Chuck Lever: "Two significant security enhancements are part of this release: - NFSD's RPC header encoding and decoding, including RPCSEC GSS and gssproxy header parsing, has been overhauled to make it more memory-safe. - Support for Kerberos AES-SHA2-based encryption types has been added for both the NFS client and server. This provides a clean path for deprecating and removing insecure encryption types based on DES and SHA-1. AES-SHA2 is also FIPS-140 compliant, so that NFS with Kerberos may now be used on systems with fips enabled. In addition to these, NFSD is now able to handle crossing into an auto-mounted mount point on an exported NFS mount. A number of fixes have been made to NFSD's server-side copy implementation. RPC metrics have been converted to per-CPU variables. This helps reduce unnecessary cross-CPU and cross-node memory bus traffic, and significantly reduces noise when KCSAN is enabled" * tag 'nfsd-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: (121 commits) NFSD: Clean up nfsd_symlink() NFSD: copy the whole verifier in nfsd_copy_write_verifier nfsd: don't fsync nfsd_files on last close SUNRPC: Fix occasional warning when destroying gss_krb5_enctypes nfsd: fix courtesy client with deny mode handling in nfs4_upgrade_open NFSD: fix problems with cleanup on errors in nfsd4_copy nfsd: fix race to check ls_layouts nfsd: don't hand out delegation on setuid files being opened for write SUNRPC: Remove ->xpo_secure_port() SUNRPC: Clean up the svc_xprt_flags() macro nfsd: remove fs/nfsd/fault_inject.c NFSD: fix leaked reference count of nfsd4_ssc_umount_item nfsd: clean up potential nfsd_file refcount leaks in COPY codepath nfsd: zero out pointers after putting nfsd_files on COPY setup error SUNRPC: Fix whitespace damage in svcauth_unix.c nfsd: eliminate __nfs4_get_fd nfsd: add some kerneldoc comments for stateid preprocessing functions nfsd: eliminate find_deleg_file_locked nfsd: don't take nfsd4_copy ref for OP_OFFLOAD_STATUS SUNRPC: Add encryption self-tests ...
2023-02-20SUNRPC: Use per-CPU counters to tally server RPC countsChuck Lever
- Improves counting accuracy - Reduces cross-CPU memory traffic Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-01-18fs: port vfs_*() helpers to struct mnt_idmapChristian Brauner
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-11-28NFSD: Add an NFSD_FILE_GC flag to enable nfsd_file garbage collectionChuck Lever
NFSv4 operations manage the lifetime of nfsd_file items they use by means of NFSv4 OPEN and CLOSE. Hence there's no need for them to be garbage collected. Introduce a mechanism to enable garbage collection for nfsd_file items used only by NFSv2/3 callers. Note that the change in nfsd_file_put() ensures that both CLOSE and DELEGRETURN will actually close out and free an nfsd_file on last reference of a non-garbage-collected file. Link: https://bugzilla.linux-nfs.org/show_bug.cgi?id=394 Suggested-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: NeilBrown <neilb@suse.de> Reviewed-by: Jeff Layton <jlayton@kernel.org>
2022-11-28NFSD: Pass the target nfsd_file to nfsd_commit()Chuck Lever
In a moment I'm going to introduce separate nfsd_file types, one of which is garbage-collected; the other, not. The garbage-collected variety is to be used by NFSv2 and v3, and the non-garbage-collected variety is to be used by NFSv4. nfsd_commit() is invoked by both NFSv3 and NFSv4 consumers. We want nfsd_commit() to find and use the correct variety of cached nfsd_file object for the NFS version that is in use. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: NeilBrown <neilb@suse.de>
2022-09-26NFSD: Refactor common code out of dirlist helpersChuck Lever
The dust has settled a bit and it's become obvious what code is totally common between nfsd_init_dirlist_pages() and nfsd3_init_dirlist_pages(). Move that common code to SUNRPC. The new helper brackets the existing xdr_init_decode_pages() API. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-09-26SUNRPC: Parametrize how much of argsize should be zeroedChuck Lever
Currently, SUNRPC clears the whole of .pc_argsize before processing each incoming RPC transaction. Add an extra parameter to struct svc_procedure to enable upper layers to reduce the amount of each operation's argument structure that is zeroed by SUNRPC. The size of struct nfsd4_compoundargs, in particular, is a lot to clear on each incoming RPC Call. A subsequent patch will cut this down to something closer to what NFSv2 and NFSv3 uses. This patch should cause no behavior changes. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-09-26NFSD: Protect against send buffer overflow in NFSv3 READChuck Lever
Since before the git era, NFSD has conserved the number of pages held by each nfsd thread by combining the RPC receive and send buffers into a single array of pages. This works because there are no cases where an operation needs a large RPC Call message and a large RPC Reply at the same time. Once an RPC Call has been received, svc_process() updates svc_rqst::rq_res to describe the part of rq_pages that can be used for constructing the Reply. This means that the send buffer (rq_res) shrinks when the received RPC record containing the RPC Call is large. A client can force this shrinkage on TCP by sending a correctly- formed RPC Call header contained in an RPC record that is excessively large. The full maximum payload size cannot be constructed in that case. Cc: <stable@vger.kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-09-26NFSD: Protect against send buffer overflow in NFSv3 READDIRChuck Lever
Since before the git era, NFSD has conserved the number of pages held by each nfsd thread by combining the RPC receive and send buffers into a single array of pages. This works because there are no cases where an operation needs a large RPC Call message and a large RPC Reply message at the same time. Once an RPC Call has been received, svc_process() updates svc_rqst::rq_res to describe the part of rq_pages that can be used for constructing the Reply. This means that the send buffer (rq_res) shrinks when the received RPC record containing the RPC Call is large. A client can force this shrinkage on TCP by sending a correctly- formed RPC Call header contained in an RPC record that is excessively large. The full maximum payload size cannot be constructed in that case. Thanks to Aleksi Illikainen and Kari Hulkko for uncovering this issue. Reported-by: Ben Ronallo <Benjamin.Ronallo@synopsys.com> Cc: <stable@vger.kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-08-04NFSD: use explicit lock/unlock for directory opsNeilBrown
When creating or unlinking a name in a directory use explicit inode_lock_nested() instead of fh_lock(), and explicit calls to fh_fill_pre_attrs() and fh_fill_post_attrs(). This is already done for renames, with lock_rename() as the explicit locking. Also move the 'fill' calls closer to the operation that might change the attributes. This way they are avoided on some error paths. For the v2-only code in nfsproc.c, the fill calls are not replaced as they aren't needed. Making the locking explicit will simplify proposed future changes to locking for directories. It also makes it easily visible exactly where pre/post attributes are used - not all callers of fh_lock() actually need the pre/post attributes. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-08-04NFSD: always drop directory lock in nfsd_unlink()NeilBrown
Some error paths in nfsd_unlink() allow it to exit without unlocking the directory. This is not a problem in practice as the directory will be locked with an fh_put(), but it is untidy and potentially confusing. This allows us to remove all the fh_unlock() calls that are immediately after nfsd_unlink() calls. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-08-04NFSD: change nfsd_create()/nfsd_symlink() to unlock directory before returning.NeilBrown
nfsd_create() usually returns with the directory still locked. nfsd_symlink() usually returns with it unlocked. This is clumsy. Until recently nfsd_create() needed to keep the directory locked until ACLs and security label had been set. These are now set inside nfsd_create() (in nfsd_setattr()) so this need is gone. So change nfsd_create() and nfsd_symlink() to always unlock, and remove any fh_unlock() calls that follow calls to these functions. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29NFSD: set attributes when creating symlinksNeilBrown
The NFS protocol includes attributes when creating symlinks. Linux does store attributes for symlinks and allows them to be set, though they are not used for permission checking. NFSD currently doesn't set standard (struct iattr) attributes when creating symlinks, but for NFSv4 it does set ACLs and security labels. This is inconsistent. To improve consistency, pass the provided attributes into nfsd_symlink() and call nfsd_create_setattr() to set them. NOTE: this results in a behaviour change for all NFS versions when the client sends non-default attributes with a SYMLINK request. With the Linux client, the only attributes are: attr.ia_mode = S_IFLNK | S_IRWXUGO; attr.ia_valid = ATTR_MODE; so the final outcome will be unchanged. Other clients might sent different attributes, and if they did they probably expect them to be honoured. We ignore any error from nfsd_create_setattr(). It isn't really clear what should be done if a file is successfully created, but the attributes cannot be set. NFS doesn't allow partial success to be reported. Reporting failure is probably more misleading than reporting success, so the status is ignored. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-07-29NFSD: introduce struct nfsd_attrsNeilBrown
The attributes that nfsd might want to set on a file include 'struct iattr' as well as an ACL and security label. The latter two are passed around quite separately from the first, in part because they are only needed for NFSv4. This leads to some clumsiness in the code, such as the attributes NOT being set in nfsd_create_setattr(). We need to keep the directory locked until all attributes are set to ensure the file is never visibile without all its attributes. This need combined with the inconsistent handling of attributes leads to more clumsiness. As a first step towards tidying this up, introduce 'struct nfsd_attrs'. This is passed (by reference) to vfs.c functions that work with attributes, and is assembled by the various nfs*proc functions which call them. As yet only iattr is included, but future patches will expand this. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-20NFSD: Refactor NFSv3 CREATEChuck Lever
The NFSv3 CREATE and NFSv4 OPEN(CREATE) use cases are about to diverge such that it makes sense to split do_nfsd_create() into one version for NFSv3 and one for NFSv4. As a first step, copy do_nfsd_create() to nfs3proc.c and remove NFSv4-specific logic. One immediate legibility benefit is that the logic for handling NFSv3 createhow is now quite straightforward. NFSv4 createhow has some subtleties that IMO do not belong in generic code. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-05-20NFSD: Clean up nfsd3_proc_create()Chuck Lever
As near as I can tell, mode bit masking and setting S_IFREG is already done by do_nfsd_create() and vfs_create(). The NFSv4 path (do_open_lookup), for example, does not bother with this special processing. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-02-09Merge tag 'nfsd-5.17-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux Pull more nfsd fixes from Chuck Lever: "Ensure that NFS clients cannot send file size or offset values that can cause the NFS server to crash or to return incorrect or surprising results. In particular, fix how the NFS server handles values larger than OFFSET_MAX" * tag 'nfsd-5.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: NFSD: Deprecate NFS_OFFSET_MAX NFSD: Fix offset type in I/O trace points NFSD: COMMIT operations must not return NFS?ERR_INVAL NFSD: Clamp WRITE offsets NFSD: Fix NFSv3 SETATTR/CREATE's handling of large file sizes NFSD: Fix ia_size underflow NFSD: Fix the behavior of READ near OFFSET_MAX
2022-02-09NFSD: COMMIT operations must not return NFS?ERR_INVALChuck Lever
Since, well, forever, the Linux NFS server's nfsd_commit() function has returned nfserr_inval when the passed-in byte range arguments were non-sensical. However, according to RFC 1813 section 3.3.21, NFSv3 COMMIT requests are permitted to return only the following non-zero status codes: NFS3ERR_IO NFS3ERR_STALE NFS3ERR_BADHANDLE NFS3ERR_SERVERFAULT NFS3ERR_INVAL is not included in that list. Likewise, NFS4ERR_INVAL is not listed in the COMMIT row of Table 6 in RFC 8881. RFC 7530 does permit COMMIT to return NFS4ERR_INVAL, but does not specify when it can or should be used. Instead of dropping or failing a COMMIT request in a byte range that is not supported, turn it into a valid request by treating one or both arguments as zero. Offset zero means start-of-file, count zero means until-end-of-file, so we only ever extend the commit range. NFS servers are always allowed to commit more and sooner than requested. The range check is no longer bounded by NFS_OFFSET_MAX, but rather by the value that is returned in the maxfilesize field of the NFSv3 FSINFO procedure or the NFSv4 maxfilesize file attribute. Note that this change results in a new pynfs failure: CMT4 st_commit.testCommitOverflow : RUNNING CMT4 st_commit.testCommitOverflow : FAILURE COMMIT with offset + count overflow should return NFS4ERR_INVAL, instead got NFS4_OK IMO the test is not correct as written: RFC 8881 does not allow the COMMIT operation to return NFS4ERR_INVAL. Reported-by: Dan Aloni <dan.aloni@vastdata.com> Cc: stable@vger.kernel.org Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Bruce Fields <bfields@fieldses.org>
2022-02-09NFSD: Clamp WRITE offsetsChuck Lever
Ensure that a client cannot specify a WRITE range that falls in a byte range outside what the kernel's internal types (such as loff_t, which is signed) can represent. The kiocb iterators, invoked in nfsd_vfs_write(), should properly limit write operations to within the underlying file system's s_maxbytes. Cc: stable@vger.kernel.org Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-02-09NFSD: Fix the behavior of READ near OFFSET_MAXChuck Lever
Dan Aloni reports: > Due to commit 8cfb9015280d ("NFS: Always provide aligned buffers to > the RPC read layers") on the client, a read of 0xfff is aligned up > to server rsize of 0x1000. > > As a result, in a test where the server has a file of size > 0x7fffffffffffffff, and the client tries to read from the offset > 0x7ffffffffffff000, the read causes loff_t overflow in the server > and it returns an NFS code of EINVAL to the client. The client as > a result indefinitely retries the request. The Linux NFS client does not handle NFS?ERR_INVAL, even though all NFS specifications permit servers to return that status code for a READ. Instead of NFS?ERR_INVAL, have out-of-range READ requests succeed and return a short result. Set the EOF flag in the result to prevent the client from retrying the READ request. This behavior appears to be consistent with Solaris NFS servers. Note that NFSv3 and NFSv4 use u64 offset values on the wire. These must be converted to loff_t internally before use -- an implicit type cast is not adequate for this purpose. Otherwise VFS checks against sb->s_maxbytes do not work properly. Reported-by: Dan Aloni <dan.aloni@vastdata.com> Cc: stable@vger.kernel.org Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-01-16Merge tag 'nfsd-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linuxLinus Torvalds
Pull nfsd updates from Chuck Lever: "Bruce has announced he is leaving Red Hat at the end of the month and is stepping back from his role as NFSD co-maintainer. As a result, this includes a patch removing him from the MAINTAINERS file. There is one patch in here that Jeff Layton was carrying in the locks tree. Since he had only one for this cycle, he asked us to send it to you via the nfsd tree. There continues to be 0-day reports from Robert Morris @MIT. This time we include a fix for a crash in the COPY_NOTIFY operation. Highlights: - Bruce steps down as NFSD maintainer - Prepare for dynamic nfsd thread management - More work on supporting re-exporting NFS mounts - One fs/locks patch on behalf of Jeff Layton Notable bug fixes: - Fix zero-length NFSv3 WRITEs - Fix directory cinfo on FS's that do not support iversion - Fix WRITE verifiers for stable writes - Fix crash on COPY_NOTIFY with a special state ID" * tag 'nfsd-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: (51 commits) SUNRPC: Fix sockaddr handling in svcsock_accept_class trace points SUNRPC: Fix sockaddr handling in the svc_xprt_create_error trace point fs/locks: fix fcntl_getlk64/fcntl_setlk64 stub prototypes nfsd: fix crash on COPY_NOTIFY with special stateid MAINTAINERS: remove bfields NFSD: Move fill_pre_wcc() and fill_post_wcc() Revert "nfsd: skip some unnecessary stats in the v4 case" NFSD: Trace boot verifier resets NFSD: Rename boot verifier functions NFSD: Clean up the nfsd_net::nfssvc_boot field NFSD: Write verifier might go backwards nfsd: Add a tracepoint for errors in nfsd4_clone_file_range() NFSD: De-duplicate net_generic(nf->nf_net, nfsd_net_id) NFSD: De-duplicate net_generic(SVC_NET(rqstp), nfsd_net_id) NFSD: Clean up nfsd_vfs_write() nfsd: Replace use of rwsem with errseq_t NFSD: Fix verifier returned in stable WRITEs nfsd: Retry once in nfsd_open on an -EOPENSTALE return nfsd: Add errno mapping for EREMOTEIO nfsd: map EBADF ...
2022-01-08NFSD: Fix zero-length NFSv3 WRITEsChuck Lever
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>
2021-12-18NFSD: Fix READDIR buffer overflowChuck Lever
If a client sends a READDIR count argument that is too small (say, zero), then the buffer size calculation in the new init_dirlist helper functions results in an underflow, allowing the XDR stream functions to write beyond the actual buffer. This calculation has always been suspect. NFSD has never sanity- checked the READDIR count argument, but the old entry encoders managed the problem correctly. With the commits below, entry encoding changed, exposing the underflow to the pointer arithmetic in xdr_reserve_space(). Modern NFS clients attempt to retrieve as much data as possible for each READDIR request. Also, we have no unit tests that exercise the behavior of READDIR at the lower bound of @count values. Thus this case was missed during testing. Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com> Fixes: f5dcccd647da ("NFSD: Update the NFSv2 READDIR entry encoder to use struct xdr_stream") Fixes: 7f87fc2d34d4 ("NFSD: Update NFSv3 READDIR entry encoders to use struct xdr_stream") Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-10-02NFSD: Have legacy NFSD WRITE decoders use xdr_stream_subsegment()Chuck Lever
Refactor. Now that the NFSv2 and NFSv3 XDR decoders have been converted to use xdr_streams, the WRITE decoder functions can use xdr_stream_subsegment() to extract the WRITE payload into its own xdr_buf, just as the NFSv4 WRITE XDR decoder currently does. That makes it possible to pass the first kvec, pages array + length, page_base, and total payload length via a single function parameter. The payload's page_base is not yet assigned or used, but will be in subsequent patches. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2021-03-22NFSD: Reduce svc_rqst::rq_pages churn during READDIR operationsChuck Lever
During NFSv2 and NFSv3 READDIR/PLUS operations, NFSD advances rq_next_page to the full size of the client-requested buffer, then releases all those pages at the end of the request. The next request to use that nfsd thread has to refill the pages. NFSD does this even when the dirlist in the reply is small. With NFSv3 clients that send READDIR operations with large buffer sizes, that can be 256 put_page/alloc_page pairs per READDIR request, even though those pages often remain unused. We can save some work by not releasing dirlist buffer pages that were not used to form the READDIR Reply. I've left the NFSv2 code alone since there are never more than three pages involved in an NFSv2 READDIR Reply. Eventually we should nail down why these pages need to be released at all in order to avoid allocating and releasing pages unnecessarily. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-03-22NFSD: Update NFSv3 READDIR entry encoders to use struct xdr_streamChuck Lever
The benefit of the xdr_stream helpers is that they transparently handle encoding an XDR data item that crosses page boundaries. Most of the open-coded logic to do that here can be eliminated. A sub-buffer and sub-stream are set up as a sink buffer for the directory entry encoder. As an entry is encoded, it is added to the end of the content in this buffer/stream. The total length of the directory list is tracked in the buffer's @len field. When it comes time to encode the Reply, the sub-buffer is merged into rq_res's page array at the correct place using xdr_write_pages(). Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-03-22NFSD: Update the NFSv3 READDIR3res encoder to use struct xdr_streamChuck Lever
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-03-22NFSD: Count bytes instead of pages in the NFSv3 READDIR encoderChuck Lever
Clean up: Counting the bytes used by each returned directory entry seems less brittle to me than trying to measure consumed pages after the fact. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-03-22NFSD: Add a helper that encodes NFSv3 directory offset cookiesChuck Lever
Refactor: De-duplicate identical code that handles encoding of directory offset cookies across page boundaries. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-03-22NFSD: Update the NFSv3 READ3res encode to use struct xdr_streamChuck Lever
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-03-22NFSD: Update the NFSv3 READLINK3res encoder to use struct xdr_streamChuck Lever
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-03-22NFSD: Update the NFSv3 LOOKUP3res encoder to use struct xdr_streamChuck Lever
Also, clean up: Rename the encoder function to match the name of the result structure in RFC 1813, consistent with other encoder function names in nfs3xdr.c. "diropres" is an NFSv2 thingie. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-03-22NFSD: Update the GETATTR3res encoder to use struct xdr_streamChuck Lever
As an additional clean up, some renaming is done to more closely reflect the data type and variable names used in the NFSv3 XDR definition provided in RFC 1813. "attrstat" is an NFSv2 thingie. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-01-25NFSD: Add helper to set up the pages where the dirlist is encodedChuck Lever
De-duplicate some code that is used by both READDIR and READDIRPLUS to build the dirlist in the Reply. Because this code is not related to decoding READ arguments, it is moved to a more appropriate spot. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-01-25NFSD: Fix returned READDIR offset cookieChuck Lever
Code inspection shows that the server's NFSv3 READDIR implementation handles offset cookies slightly differently than the NFSv2 READDIR, NFSv3 READDIRPLUS, and NFSv4 READDIR implementations, and there doesn't seem to be any need for this difference. As a clean up, I copied the logic from nfsd3_proc_readdirplus(). Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-01-25NFSD: Update READLINK3arg decoder to use struct xdr_streamChuck Lever
The NFSv3 READLINK request takes a single filehandle, so it can re-use GETATTR's decoder. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-01-25NFSD: Update READ3arg decoder to use struct xdr_streamChuck Lever
The code that sets up rq_vec is refactored so that it is now adjacent to the nfsd_read() call site where it is used. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-01-25NFSD: Update GETATTR3args decoder to use struct xdr_streamChuck Lever
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2021-01-25SUNRPC: Make trace_svc_process() display the RPC procedure symbolicallyChuck Lever
The next few patches will employ these strings to help make server- side trace logs more human-readable. A similar technique is already in use in kernel RPC client code. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2020-11-30NFSD: Add common helpers to decode void args and encode void resultsChuck Lever
Start off the conversion to xdr_stream by de-duplicating the functions that decode void arguments and encode void results. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2020-11-30nfsd/nfs3: remove unused macro nfsd3_fhandleresAlex Shi
The macro is unused, remove it to tame gcc warning: fs/nfsd/nfs3proc.c:702:0: warning: macro "nfsd3_fhandleres" is not used [-Wunused-macros] Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: linux-nfs@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2020-11-05NFSD: MKNOD should return NFSERR_BADTYPE instead of NFSERR_INVALChuck Lever
A late paragraph of RFC 1813 Section 3.3.11 states: | ... if the server does not support the target type or the | target type is illegal, the error, NFS3ERR_BADTYPE, should | be returned. Note that NF3REG, NF3DIR, and NF3LNK are | illegal types for MKNOD. The Linux NFS server incorrectly returns NFSERR_INVAL in these cases. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2020-10-12NFSD: Hoist status code encoding into XDR encoder functionsChuck Lever
The original intent was presumably to reduce code duplication. The trade-off was: - No support for an NFSD proc function returning a non-success RPC accept_stat value. - No support for void NFS replies to non-NULL procedures. - Everyone pays for the deduplication with a few extra conditional branches in a hot path. In addition, nfsd_dispatch() leaves *statp uninitialized in the success path, unlike svc_generic_dispatch(). Address all of these problems by moving the logic for encoding the NFS status code into the NFS XDR encoders themselves. Then update the NFS .pc_func methods to return an RPC accept_stat value. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2020-10-02NFSD: Remove the RETURN_STATUS() macroChuck Lever
Refactor: I'm about to change the return value from .pc_func. Clear the way by replacing the RETURN_STATUS() macro with logic that plants the status code directly into the response structure. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>