The RC4-HMAC-MD5 KerberosV algorithm is based on RFC 4757 [0], which
was specifically issued for interoperability with Windows 2000, but was
never intended to receive the same level of support. The RFC says
The IETF Kerberos community supports publishing this specification as
an informational document in order to describe this widely
implemented technology. However, while these encryption types
provide the operations necessary to implement the base Kerberos
specification [RFC4120], they do not provide all the required
operations in the Kerberos cryptography framework [RFC3961]. As a
result, it is not generally possible to implement potential
extensions to Kerberos using these encryption types. The Kerberos
encryption type negotiation mechanism [RFC4537] provides one approach
for using such extensions even when a Kerberos infrastructure uses
long-term RC4 keys. Because this specification does not implement
operations required by RFC 3961 and because of security concerns with
the use of RC4 and MD4 discussed in Section 8, this specification is
not appropriate for publication on the standards track.
The RC4-HMAC encryption types are used to ease upgrade of existing
Windows NT environments, provide strong cryptography (128-bit key
lengths), and provide exportable (meet United States government
export restriction requirements) encryption. This document describes
the implementation of those encryption types.
Furthermore, this RFC was re-classified as 'historic' by RFC 8429 [1] in
2018, stating that 'none of the encryption types it specifies should be
used'
Note that other outdated algorithms are left in place (some of which are
guarded by CONFIG_SUNRPC_DISABLE_INSECURE_ENCTYPES), so this should only
adversely affect interoperability with Windows NT/2000 systems that have
not received any updates since 2008 (but are connected to a network
nonetheless)
[0] https://tools.ietf.org/html/rfc4757
[1] https://tools.ietf.org/html/rfc8429
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pull NFS client updates from Trond Myklebust:
"Stable fixes:
- pNFS: Don't return layout segments that are being used for I/O
- pNFS: Don't move layout segments off the active list when being used for I/O
Features:
- NFS: Add support for user xattrs through the NFSv4.2 protocol
- NFS: Allow applications to speed up readdir+statx() using AT_STATX_DONT_SYNC
- NFSv4.0 allow nconnect for v4.0
Bugfixes and cleanups:
- nfs: ensure correct writeback errors are returned on close()
- nfs: nfs_file_write() should check for writeback errors
- nfs: Fix getxattr kernel panic and memory overflow
- NFS: Fix the pNFS/flexfiles mirrored read failover code
- SUNRPC: dont update timeout value on connection reset
- freezer: Add unsafe versions of freezable_schedule_timeout_interruptible for NFS
- sunrpc: destroy rpc_inode_cachep after unregister_filesystem"
* tag 'nfs-for-5.9-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (32 commits)
NFS: Fix flexfiles read failover
fs: nfs: delete repeated words in comments
rpc_pipefs: convert comma to semicolon
nfs: Fix getxattr kernel panic and memory overflow
NFS: Don't return layout segments that are in use
NFS: Don't move layouts to plh_return_segs list while in use
NFS: Add layout segment info to pnfs read/write/commit tracepoints
NFS: Add tracepoints for layouterror and layoutstats.
NFS: Report the stateid + status in trace_nfs4_layoutreturn_on_close()
SUNRPC dont update timeout value on connection reset
nfs: nfs_file_write() should check for writeback errors
nfs: ensure correct writeback errors are returned on close()
NFSv4.2: xattr cache: get rid of cache discard work queue
NFS: remove redundant initialization of variable result
NFSv4.0 allow nconnect for v4.0
freezer: Add unsafe versions of freezable_schedule_timeout_interruptible for NFS
sunrpc: destroy rpc_inode_cachep after unregister_filesystem
NFSv4.2: add client side xattr caching.
NFSv4.2: hook in the user extended attribute handlers
NFSv4.2: add the extended attribute proc functions.
...
Current behaviour: every time a v3 operation is re-sent to the server
we update (double) the timeout. There is no distinction between whether
or not the previous timer had expired before the re-sent happened.
Here's the scenario:
1. Client sends a v3 operation
2. Server RST-s the connection (prior to the timeout) (eg., connection
is immediately reset)
3. Client re-sends a v3 operation but the timeout is now 120sec.
As a result, an application sees 2mins pause before a retry in case
server again does not reply.
Instead, this patch proposes to keep track off when the minor timeout
should happen and if it didn't, then don't update the new timeout.
Value is updated based on the previous value to make timeouts
predictable.
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
First, refactor: Dereference the svc_rdma_send_ctxt inside
svc_rdma_send() instead of at every call site.
Then, it can be passed into trace_svcrdma_post_send() to get the
proper completion ID.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Set up a completion ID in each svc_rdma_send_ctxt. The ID is used
to match an incoming Send completion to a transport and to a
previous ib_post_send().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Set up a completion ID in each svc_rdma_recv_ctxt. The ID is used
to match an incoming Receive completion to a transport and to a
previous ib_post_recv().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The goal is to replace CQE kernel memory addresses in completion-
related tracepoints.
Each completion ID matches an incoming Send or Receive completion
to a Completion Queue and to a previous ib_post_*(). The ID can
then be displayed in an error message or recorded in a trace
record.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Use these helpers in a few spots to demonstrate their use.
The remaining open-coded discriminator checks in rpcrdma will be
addressed in subsequent patches.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Pull NFS client updates from Anna Schumaker:
"New features and improvements:
- Sunrpc receive buffer sizes only change when establishing a GSS credentials
- Add more sunrpc tracepoints
- Improve on tracepoints to capture internal NFS I/O errors
Other bugfixes and cleanups:
- Move a dprintk() to after a call to nfs_alloc_fattr()
- Fix off-by-one issues in rpc_ntop6
- Fix a few coccicheck warnings
- Use the correct SPDX license identifiers
- Fix rpc_call_done assignment for BIND_CONN_TO_SESSION
- Replace zero-length array with flexible array
- Remove duplicate headers
- Set invalid blocks after NFSv4 writes to update space_used attribute
- Fix direct WRITE throughput regression"
* tag 'nfs-for-5.8-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (27 commits)
NFS: Fix direct WRITE throughput regression
SUNRPC: rpc_xprt lifetime events should record xprt->state
xprtrdma: Make xprt_rdma_slot_table_entries static
nfs: set invalid blocks after NFSv4 writes
NFS: remove redundant initialization of variable result
sunrpc: add missing newline when printing parameter 'auth_hashtable_size' by sysfs
NFS: Add a tracepoint in nfs_set_pgio_error()
NFS: Trace short NFS READs
NFS: nfs_xdr_status should record the procedure name
SUNRPC: Set SOFTCONN when destroying GSS contexts
SUNRPC: rpc_call_null_helper() should set RPC_TASK_SOFT
SUNRPC: rpc_call_null_helper() already sets RPC_TASK_NULLCREDS
SUNRPC: trace RPC client lifetime events
SUNRPC: Trace transport lifetime events
SUNRPC: Split the xdr_buf event class
SUNRPC: Add tracepoint to rpc_call_rpcerror()
SUNRPC: Update the RPC_SHOW_SOCKET() macro
SUNRPC: Update the rpc_show_task_flags() macro
SUNRPC: Trace GSS context lifetimes
SUNRPC: receive buffer size estimation values almost never change
...
Avoid unnecessary cache sloshing by placing the buffer size
estimation update logic behind an atomic bit flag.
The size of GSS information included in each wrapped Reply does
not change during the lifetime of a GSS context. Therefore, the
au_rslack and au_ralign fields need to be updated only once after
establishing a fresh GSS credential.
Thus a slack size update must occur after a cred is created,
duplicated, renewed, or expires. I'm not sure I have this exactly
right. A trace point is introduced to track updates to these
variables to enable troubleshooting the problem if I missed a spot.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
gss_mech_register() calls svcauth_gss_register_pseudoflavor() for each
flavour, but gss_mech_unregister() does not call auth_domain_put().
This is unbalanced and makes it impossible to reload the module.
Change svcauth_gss_register_pseudoflavor() to return the registered
auth_domain, and save it for later release.
Cc: stable@vger.kernel.org (v2.6.12+)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206651
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Highlights of this series:
* Remove serialization of sending RPC/RDMA Replies
* Convert the TCP socket send path to use xdr_buf::bvecs (pre-requisite for
RPC-on-TLS)
* Fix svcrdma backchannel sendto return code
* Convert a number of dprintk call sites to use tracepoints
* Fix the "suggest braces around empty body in an 'else' statement" warning
This function is not currently "generic" so remove the documenting
comment and rename it appropriately. Its internals are converted to
use bio_vecs for reading from the transport socket.
In existing typical sunrpc uses of bio_vecs, the bio_vec array is
allocated dynamically. Here, instead, an array of bio_vecs is added
to svc_rqst. The lifetime of this array can be greater than one call
to xpo_recvfrom():
- Multiple calls to xpo_recvfrom() might be needed to read an RPC
message completely.
- At some later point, rq_arg.bvecs will point to this array and it
will carry the received message into svc_process().
I also expect that a future optimization will remove either the
rq_vec or rq_pages array in favor of rq_bvec, thus conserving the
size of struct svc_rqst.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Clean up. I find the name of the svc_sock::sk_reclen field
confusing, so I've changed it to better reflect its function. This
field is not read directly to get the record length. Rather, it is
a buffer containing a record marker that needs to be decoded.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Clean up: Commit d21b05f101 ("rdma: SVCRMDA Header File")
introduced the SVCRDMA_DEBUG macro, but it doesn't seem to have been
used.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Way back when I was writing the RPC/RDMA server-side backchannel
code, I misread the TCP backchannel reply handler logic. When
svc_tcp_recvfrom() successfully receives a backchannel reply, it
does not return -EAGAIN. It sets XPT_DATA and returns zero.
Update svc_rdma_recvfrom() to return zero. Here, XPT_DATA doesn't
need to be set again: it is set whenever a new message is received,
behind a spin lock in a single threaded context.
Also, if handling the cb reply is not successful, the message is
simply dropped. There's no special message framing to deal with as
there is in the TCP case.
Now that the handle_bc_reply() return value is ignored, I've removed
the dprintk call sites in the error exit of handle_bc_reply() in
favor of trace points in other areas that already report the error
cases.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
It appears that the RPC/RDMA transport does not need serialization
of calls to its xpo_sendto method. Move the mutex into the socket
methods that still need that serialization.
Tail latencies are unambiguously better with this patch applied.
fio randrw 8KB 70/30 on NFSv3, smaller numbers are better:
clat percentiles (usec):
With xpt_mutex:
r | 99.99th=[ 8848]
w | 99.99th=[ 9634]
Without xpt_mutex:
r | 99.99th=[ 8586]
w | 99.99th=[ 8979]
Serializing the construction of RPC/RDMA transport headers is not
really necessary at this point, because the Linux NFS server
implementation never changes its credit grant on a connection. If
that should change, then svc_rdma_sendto will need to serialize
access to the transport's credit grant fields.
Reported-by: kbuild test robot <lkp@intel.com>
[ cel: fix uninitialized variable warning ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Pull nfsd fixes from Chuck Lever:
"Resolve a data integrity problem with NFSD that I inadvertently
introduced last year.
The change I made makes the NFS server's duplicate reply cache
ineffective when krb5i or krb5p are in use, thus allowing the replay
of non-idempotent NFS requests such as RENAME, SETATTR, or even
WRITEs"
* tag 'nfsd-5.7-rc-2' of git://git.linux-nfs.org/projects/cel/cel-2.6:
SUNRPC: Revert 241b1f419f ("SUNRPC: Remove xdr_buf_trim()")
SUNRPC: Fix GSS privacy computation of auth->au_ralign
SUNRPC: Add "@len" parameter to gss_unwrap()
We currently revoke read delegations on any write open or any operation
that modifies file data or metadata (including rename, link, and
unlink). But if the delegation in question is the only read delegation
and is held by the client performing the operation, that's not really
necessary.
It's not always possible to prevent this in the NFSv4.0 case, because
there's not always a way to determine which client an NFSv4.0 delegation
came from. (In theory we could try to guess this from the transport
layer, e.g., by assuming all traffic on a given TCP connection comes
from the same client. But that's not really correct.)
In the NFSv4.1 case the session layer always tells us the client.
This patch should remove such self-conflicts in all cases where we can
reliably determine the client from the compound.
To do that we need to track "who" is performing a given (possibly
lease-breaking) file operation. We're doing that by storing the
information in the svc_rqst and using kthread_data() to map the current
task back to a svc_rqst.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Pull NFS client bugfixes from Trond Myklebust:
"Highlights include:
Stable fixes:
- fix handling of backchannel binding in BIND_CONN_TO_SESSION
Bugfixes:
- Fix a credential use-after-free issue in pnfs_roc()
- Fix potential posix_acl refcnt leak in nfs3_set_acl
- defer slow parts of rpc_free_client() to a workqueue
- Fix an Oopsable race in __nfs_list_for_each_server()
- Fix trace point use-after-free race
- Regression: the RDMA client no longer responds to server disconnect
requests
- Fix return values of xdr_stream_encode_item_{present, absent}
- _pnfs_return_layout() must always wait for layoutreturn completion
Cleanups:
- Remove unreachable error conditions"
* tag 'nfs-for-5.7-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
NFS: Fix a race in __nfs_list_for_each_server()
NFSv4.1: fix handling of backchannel binding in BIND_CONN_TO_SESSION
SUNRPC: defer slow parts of rpc_free_client() to a workqueue.
NFSv4: Remove unreachable error condition due to rpc_run_task()
SUNRPC: Remove unreachable error condition
xprtrdma: Fix use of xdr_stream_encode_item_{present, absent}
xprtrdma: Fix trace point use-after-free race
xprtrdma: Restore wake-up-all to rpcrdma_cm_event_handler()
nfs: Fix potential posix_acl refcnt leak in nfs3_set_acl
NFS/pnfs: Fix a credential use-after-free issue in pnfs_roc()
NFS/pnfs: Ensure that _pnfs_return_layout() waits for layoutreturn completion
Currently, if the client sends BIND_CONN_TO_SESSION with
NFS4_CDFC4_FORE_OR_BOTH but only gets NFS4_CDFS4_FORE back it ignores
that it wasn't able to enable a backchannel.
To make sure, the client sends BIND_CONN_TO_SESSION as the first
operation on the connections (ie., no other session compounds haven't
been sent before), and if the client's request to bind the backchannel
is not satisfied, then reset the connection and retry.
Cc: stable@vger.kernel.org
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Ard Biesheuvel
Linus Torvalds
Olga Kornievskaia
Chuck Lever
NeilBrown
J. Bruce Fields