In the original code, the "if (*lenp < 0)" check didn't work because
"*lenp" is unsigned.  Fortunately, the memory_read_from_buffer() call
will never fail in this context so it doesn't affect runtime.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

You can't write to this file because the permissions are 0444.  But
it sort of looked like you could do a write and it would result in
a read.  Then it looked like proc_sys_call_handler() just ignored
it.  Which is confusing.  It's more clear if the "write" just
returns zero.

Also, the "lenp" pointer is never NULL so that check can be removed.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Pull nfsd updates from Bruce Fields:
 "The one new feature this time, from Anna Schumaker, is READ_PLUS,
  which has the same arguments as READ but allows the server to return
  an array of data and hole extents.

  Otherwise it's a lot of cleanup and bugfixes"

* tag 'nfsd-5.10' of git://linux-nfs.org/~bfields/linux: (43 commits)
  NFSv4.2: Fix NFS4ERR_STALE error when doing inter server copy
  SUNRPC: fix copying of multiple pages in gss_read_proxy_verf()
  sunrpc: raise kernel RPC channel buffer size
  svcrdma: fix bounce buffers for unaligned offsets and multiple pages
  nfsd: remove unneeded break
  net/sunrpc: Fix return value for sysctl sunrpc.transports
  NFSD: Encode a full READ_PLUS reply
  NFSD: Return both a hole and a data segment
  NFSD: Add READ_PLUS hole segment encoding
  NFSD: Add READ_PLUS data support
  NFSD: Hoist status code encoding into XDR encoder functions
  NFSD: Map nfserr_wrongsec outside of nfsd_dispatch
  NFSD: Remove the RETURN_STATUS() macro
  NFSD: Call NFSv2 encoders on error returns
  NFSD: Fix .pc_release method for NFSv2
  NFSD: Remove vestigial typedefs
  NFSD: Refactor nfsd_dispatch() error paths
  NFSD: Clean up nfsd_dispatch() variables
  NFSD: Clean up stale comments in nfsd_dispatch()
  NFSD: Clean up switch statement in nfsd_dispatch()
  ...

Pull NFS client updates from Anna Schumaker:
 "Stable Fixes:
   - Wait for stateid updates after CLOSE/OPEN_DOWNGRADE # v5.4+
   - Fix nfs_path in case of a rename retry
   - Support EXCHID4_FLAG_SUPP_FENCE_OPS v4.2 EXCHANGE_ID flag

  New features and improvements:
   - Replace dprintk() calls with tracepoints
   - Make cache consistency bitmap dynamic
   - Added support for the NFS v4.2 READ_PLUS operation
   - Improvements to net namespace uniquifier

  Other bugfixes and cleanups:
   - Remove redundant clnt pointer
   - Don't update timeout values on connection resets
   - Remove redundant tracepoints
   - Various cleanups to comments
   - Fix oops when trying to use copy_file_range with v4.0 source server
   - Improvements to flexfiles mirrors
   - Add missing 'local_lock=posix' mount option"

* tag 'nfs-for-5.10-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (55 commits)
  NFSv4.2: support EXCHGID4_FLAG_SUPP_FENCE_OPS 4.2 EXCHANGE_ID flag
  NFSv4: Fix up RCU annotations for struct nfs_netns_client
  NFS: Only reference user namespace from nfs4idmap struct instead of cred
  nfs: add missing "posix" local_lock constant table definition
  NFSv4: Use the net namespace uniquifier if it is set
  NFSv4: Clean up initialisation of uniquified client id strings
  NFS: Decode a full READ_PLUS reply
  SUNRPC: Add an xdr_align_data() function
  NFS: Add READ_PLUS hole segment decoding
  SUNRPC: Add the ability to expand holes in data pages
  SUNRPC: Split out _shift_data_right_tail()
  SUNRPC: Split out xdr_realign_pages() from xdr_align_pages()
  NFS: Add READ_PLUS data segment support
  NFS: Use xdr_page_pos() in NFSv4 decode_getacl()
  SUNRPC: Implement a xdr_page_pos() function
  SUNRPC: Split out a function for setting current page
  NFS: fix nfs_path in case of a rename retry
  fs: nfs: return per memcg count for xattr shrinkers
  NFSv4: Wait for stateid updates after CLOSE/OPEN_DOWNGRADE
  nfs: remove incorrect fallthrough label
  ...

When the passed token is longer than 4032 bytes, the remaining part
of the token must be copied from the rqstp->rq_arg.pages. But the
copy must make sure it happens in a consecutive way.

With the existing code, the first memcpy copies 'length' bytes from
argv->iobase, but since the header is in front, this never fills the
whole first page of in_token->pages.

The mecpy in the loop copies the following bytes, but starts writing at
the next page of in_token->pages.  This leaves the last bytes of page 0
unwritten.

Symptoms were that users with many groups were not able to access NFS
exports, when using Active Directory as the KDC.

Signed-off-by: Martijn de Gouw <martijn.de.gouw@prodrive-technologies.com>
Fixes: 5866efa8cbfb "SUNRPC: Fix svcauth_gss_proxy_init()"
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Its possible that using AUTH_SYS and mountd manage-gids option a
user may hit the 8k RPC channel buffer limit. This have been observed
on field, causing unanswered RPCs on clients after mountd fails to
write on channel :

rpc.mountd[11231]: auth_unix_gid: error writing reply

Userland nfs-utils uses a buffer size of 32k (RPC_CHAN_BUF_SIZE), so
lets match those two.

Signed-off-by: Roberto Bergantinos Corpas <rbergant@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

This was discovered using O_DIRECT at the client side, with small
unaligned file offsets or IOs that span multiple file pages.

Fixes: e248aa7be86 ("svcrdma: Remove max_sge check at connect time")
Signed-off-by: Dan Aloni <dan@kernelim.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Fix returning value for sysctl sunrpc.transports.
Return error code from sysctl proc_handler function proc_do_xprt instead of number of the written bytes.
Otherwise sysctl returns random garbage for this key.

Since v1:
- Handle negative returned value from memory_read_from_buffer as an error

Signed-off-by: Artur Molchanov <arturmolchanov@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Pull networking updates from Jakub Kicinski:

 - Add redirect_neigh() BPF packet redirect helper, allowing to limit
   stack traversal in common container configs and improving TCP
   back-pressure.

   Daniel reports ~10Gbps => ~15Gbps single stream TCP performance gain.

 - Expand netlink policy support and improve policy export to user
   space. (Ge)netlink core performs request validation according to
   declared policies. Expand the expressiveness of those policies
   (min/max length and bitmasks). Allow dumping policies for particular
   commands. This is used for feature discovery by user space (instead
   of kernel version parsing or trial and error).

 - Support IGMPv3/MLDv2 multicast listener discovery protocols in
   bridge.

 - Allow more than 255 IPv4 multicast interfaces.

 - Add support for Type of Service (ToS) reflection in SYN/SYN-ACK
   packets of TCPv6.

 - In Multi-patch TCP (MPTCP) support concurrent transmission of data on
   multiple subflows in a load balancing scenario. Enhance advertising
   addresses via the RM_ADDR/ADD_ADDR options.

 - Support SMC-Dv2 version of SMC, which enables multi-subnet
   deployments.

 - Allow more calls to same peer in RxRPC.

 - Support two new Controller Area Network (CAN) protocols - CAN-FD and
   ISO 15765-2:2016.

 - Add xfrm/IPsec compat layer, solving the 32bit user space on 64bit
   kernel problem.

 - Add TC actions for implementing MPLS L2 VPNs.

 - Improve nexthop code - e.g. handle various corner cases when nexthop
   objects are removed from groups better, skip unnecessary
   notifications and make it easier to offload nexthops into HW by
   converting to a blocking notifier.

 - Support adding and consuming TCP header options by BPF programs,
   opening the doors for easy experimental and deployment-specific TCP
   option use.

 - Reorganize TCP congestion control (CC) initialization to simplify
   life of TCP CC implemented in BPF.

 - Add support for shipping BPF programs with the kernel and loading
   them early on boot via the User Mode Driver mechanism, hence reusing
   all the user space infra we have.

 - Support sleepable BPF programs, initially targeting LSM and tracing.

 - Add bpf_d_path() helper for returning full path for given 'struct
   path'.

 - Make bpf_tail_call compatible with bpf-to-bpf calls.

 - Allow BPF programs to call map_update_elem on sockmaps.

 - Add BPF Type Format (BTF) support for type and enum discovery, as
   well as support for using BTF within the kernel itself (current use
   is for pretty printing structures).

 - Support listing and getting information about bpf_links via the bpf
   syscall.

 - Enhance kernel interfaces around NIC firmware update. Allow
   specifying overwrite mask to control if settings etc. are reset
   during update; report expected max time operation may take to users;
   support firmware activation without machine reboot incl. limits of
   how much impact reset may have (e.g. dropping link or not).

 - Extend ethtool configuration interface to report IEEE-standard
   counters, to limit the need for per-vendor logic in user space.

 - Adopt or extend devlink use for debug, monitoring, fw update in many
   drivers (dsa loop, ice, ionic, sja1105, qed, mlxsw, mv88e6xxx,
   dpaa2-eth).

 - In mlxsw expose critical and emergency SFP module temperature alarms.
   Refactor port buffer handling to make the defaults more suitable and
   support setting these values explicitly via the DCBNL interface.

 - Add XDP support for Intel's igb driver.

 - Support offloading TC flower classification and filtering rules to
   mscc_ocelot switches.

 - Add PTP support for Marvell Octeontx2 and PP2.2 hardware, as well as
   fixed interval period pulse generator and one-step timestamping in
   dpaa-eth.

 - Add support for various auth offloads in WiFi APs, e.g. SAE (WPA3)
   offload.

 - Add Lynx PHY/PCS MDIO module, and convert various drivers which have
   this HW to use it. Convert mvpp2 to split PCS.

 - Support Marvell Prestera 98DX3255 24-port switch ASICs, as well as
   7-port Mediatek MT7531 IP.

 - Add initial support for QCA6390 and IPQ6018 in ath11k WiFi driver,
   and wcn3680 support in wcn36xx.

 - Improve performance for packets which don't require much offloads on
   recent Mellanox NICs by 20% by making multiple packets share a
   descriptor entry.

 - Move chelsio inline crypto drivers (for TLS and IPsec) from the
   crypto subtree to drivers/net. Move MDIO drivers out of the phy
   directory.

 - Clean up a lot of W=1 warnings, reportedly the actively developed
   subsections of networking drivers should now build W=1 warning free.

 - Make sure drivers don't use in_interrupt() to dynamically adapt their
   code. Convert tasklets to use new tasklet_setup API (sadly this
   conversion is not yet complete).

* tag 'net-next-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2583 commits)
  Revert "bpfilter: Fix build error with CONFIG_BPFILTER_UMH"
  net, sockmap: Don't call bpf_prog_put() on NULL pointer
  bpf, selftest: Fix flaky tcp_hdr_options test when adding addr to lo
  bpf, sockmap: Add locking annotations to iterator
  netfilter: nftables: allow re-computing sctp CRC-32C in 'payload' statements
  net: fix pos incrementment in ipv6_route_seq_next
  net/smc: fix invalid return code in smcd_new_buf_create()
  net/smc: fix valid DMBE buffer sizes
  net/smc: fix use-after-free of delayed events
  bpfilter: Fix build error with CONFIG_BPFILTER_UMH
  cxgb4/ch_ipsec: Replace the module name to ch_ipsec from chcr
  net: sched: Fix suspicious RCU usage while accessing tcf_tunnel_info
  bpf: Fix register equivalence tracking.
  rxrpc: Fix loss of final ack on shutdown
  rxrpc: Fix bundle counting for exclusive connections
  netfilter: restore NF_INET_NUMHOOKS
  ibmveth: Identify ingress large send packets.
  ibmveth: Switch order of ibmveth_helper calls.
  cxgb4: handle 4-tuple PEDIT to NAT mode translation
  selftests: Add VRF route leaking tests
  ...

Pull crypto updates from Herbert Xu:
 "API:
   - Allow DRBG testing through user-space af_alg
   - Add tcrypt speed testing support for keyed hashes
   - Add type-safe init/exit hooks for ahash

  Algorithms:
   - Mark arc4 as obsolete and pending for future removal
   - Mark anubis, khazad, sead and tea as obsolete
   - Improve boot-time xor benchmark
   - Add OSCCA SM2 asymmetric cipher algorithm and use it for integrity

  Drivers:
   - Fixes and enhancement for XTS in caam
   - Add support for XIP8001B hwrng in xiphera-trng
   - Add RNG and hash support in sun8i-ce/sun8i-ss
   - Allow imx-rngc to be used by kernel entropy pool
   - Use crypto engine in omap-sham
   - Add support for Ingenic X1830 with ingenic"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (205 commits)
  X.509: Fix modular build of public_key_sm2
  crypto: xor - Remove unused variable count in do_xor_speed
  X.509: fix error return value on the failed path
  crypto: bcm - Verify GCM/CCM key length in setkey
  crypto: qat - drop input parameter from adf_enable_aer()
  crypto: qat - fix function parameters descriptions
  crypto: atmel-tdes - use semicolons rather than commas to separate statements
  crypto: drivers - use semicolons rather than commas to separate statements
  hwrng: mxc-rnga - use semicolons rather than commas to separate statements
  hwrng: iproc-rng200 - use semicolons rather than commas to separate statements
  hwrng: stm32 - use semicolons rather than commas to separate statements
  crypto: xor - use ktime for template benchmarking
  crypto: xor - defer load time benchmark to a later time
  crypto: hisilicon/zip - fix the uninitalized 'curr_qm_qp_num'
  crypto: hisilicon/zip - fix the return value when device is busy
  crypto: hisilicon/zip - fix zero length input in GZIP decompress
  crypto: hisilicon/zip - fix the uncleared debug registers
  lib/mpi: Fix unused variable warnings
  crypto: x86/poly1305 - Remove assignments with no effect
  hwrng: npcm - modify readl to readb
  ...