We're unintentionally limiting the number of slots per nfsv4.1 session
to 10. Often more than 10 simultaneous RPCs are needed for the best
performance.
This calculation was meant to prevent any one client from using up more
than a third of the limit we set for total memory use across all clients
and sessions. Instead, it's limiting the client to a third of the
maximum for a single session.
Fix this.
Reported-by: Chris Tracy <ctracy@engr.scu.edu>
Cc: stable@vger.kernel.org
Fixes: de766e5704 "nfsd: give out fewer session slots as limit approaches"
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
NFSv4.2 client, and cleaning up some convoluted backchannel server code
in the process. Otherwise, miscellaneous smaller bugfixes and cleanup.
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Merge tag 'nfsd-4.21' of git://linux-nfs.org/~bfields/linux
Pull nfsd updates from Bruce Fields:
"Thanks to Vasily Averin for fixing a use-after-free in the
containerized NFSv4.2 client, and cleaning up some convoluted
backchannel server code in the process.
Otherwise, miscellaneous smaller bugfixes and cleanup"
* tag 'nfsd-4.21' of git://linux-nfs.org/~bfields/linux: (25 commits)
nfs: fixed broken compilation in nfs_callback_up_net()
nfs: minor typo in nfs4_callback_up_net()
sunrpc: fix debug message in svc_create_xprt()
sunrpc: make visible processing error in bc_svc_process()
sunrpc: remove unused xpo_prep_reply_hdr callback
sunrpc: remove svc_rdma_bc_class
sunrpc: remove svc_tcp_bc_class
sunrpc: remove unused bc_up operation from rpc_xprt_ops
sunrpc: replace svc_serv->sv_bc_xprt by boolean flag
sunrpc: use-after-free in svc_process_common()
sunrpc: use SVC_NET() in svcauth_gss_* functions
nfsd: drop useless LIST_HEAD
lockd: Show pid of lockd for remote locks
NFSD remove OP_CACHEME from 4.2 op_flags
nfsd: Return EPERM, not EACCES, in some SETATTR cases
sunrpc: fix cache_head leak due to queued request
nfsd: clean up indentation, increase indentation in switch statement
svcrdma: Optimize the logic that selects the R_key to invalidate
nfsd: fix a warning in __cld_pipe_upcall()
nfsd4: fix crash on writing v4_end_grace before nfsd startup
...
posix_unblock_lock() is not specific to posix locks, and behaves
nearly identically to locks_delete_block() - the former returning a
status while the later doesn't.
So discard posix_unblock_lock() and use locks_delete_block() instead,
after giving that function an appropriate return value.
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Trivial fix to clean up indentation, add in missing tabs.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
alloc_init_deleg() both allocates an nfs4_delegation, and
bumps the refcount on odstate. So after this point, we need to
put_clnt_odstate() and nfs4_put_stid() to not leave the odstate
refcount inappropriately bumped.
Signed-off-by: Andrew Elble <aweits@rit.edu>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Upon receiving a request for async copy, create a new kthread. If we
get asynchronous request, make sure to copy the needed arguments/state
from the stack before starting the copy. Then start the thread and reply
back to the client indicating copy is asynchronous.
nfsd_copy_file_range() will copy in a loop over the total number of
bytes is needed to copy. In case a failure happens in the middle, we
ignore the error and return how much we copied so far. Once done
creating a workitem for the callback workqueue and send CB_OFFLOAD with
the results.
The lifetime of the copy stateid is bound to the vfs copy. This way we
don't need to keep the nfsd_net structure for the callback. We could
keep it around longer so that an OFFLOAD_STATUS that came late would
still get results, but clients should be able to deal without that.
We handle OFFLOAD_CANCEL by sending a signal to the copy thread and
calling kthread_stop.
A client should cancel any ongoing copies before calling DESTROY_CLIENT;
if not, we return a CLIENT_BUSY error.
If the client is destroyed for some other reason (lease expiration, or
server shutdown), we must clean up any ongoing copies ourselves.
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
[colin.king@canonical.com: fix leak in error case]
[bfields@fieldses.org: remove signalling, merge patches]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Clean up: The global callback_cred is no longer used, so it can be
removed.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
NFSv4.0 callback needs to know the GSS target name the client used
when it established its lease. That information is available from
the GSS context created by gssproxy. Make it available in each
svc_cred.
Note this will also give us access to the real target service
principal name (which is typically "nfs", but spec does not require
that).
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
nfsd and lockd call vfs_lock_file() to lock/unlock the inode
returned by locks_inode(file).
Many places in nfsd/lockd code use the inode returned by
file_inode(file) for lock manipulation. With Overlayfs, file_inode()
(the underlying inode) is not the same object as locks_inode() (the
overlay inode). This can result in "Leaked POSIX lock" messages
and eventually to a kernel crash as reported by Eddie Horng:
https://marc.info/?l=linux-unionfs&m=153086643202072&w=2
Fix all the call sites in nfsd/lockd that should use locks_inode().
This is a correctness bug that manifested when overlayfs gained
NFS export support in v4.16.
Reported-by: Eddie Horng <eddiehorng.tw@gmail.com>
Tested-by: Eddie Horng <eddiehorng.tw@gmail.com>
Cc: Jeff Layton <jlayton@kernel.org>
Fixes: 8383f17488 ("ovl: wire up NFS export operations")
Cc: stable@vger.kernel.org
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
It's inode->i_lock that's now taken in setlease and break_lease, instead
of the big kernel lock.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The name of this variable doesn't fit the type. And we only ever use
one field of it.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Make the function prototype match the name a little better.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
If the client is only renewing state a little sooner than once a lease
period, then it might not discover the server has restarted till close
to the end of the grace period, and might run out of time to do the
actual reclaim.
Extend the grace period by a second each time we notice there are
clients still trying to reclaim, up to a limit of another whole lease
period.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
- Additional struct_size() conversions (Matthew, Kees)
- Explicitly reported overflow fixes (Silvio, Kees)
- Add missing kvcalloc() function (Kees)
- Treewide conversions of allocators to use either 2-factor argument
variant when available, or array_size() and array3_size() as needed (Kees)
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Merge tag 'overflow-v4.18-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull more overflow updates from Kees Cook:
"The rest of the overflow changes for v4.18-rc1.
This includes the explicit overflow fixes from Silvio, further
struct_size() conversions from Matthew, and a bug fix from Dan.
But the bulk of it is the treewide conversions to use either the
2-factor argument allocators (e.g. kmalloc(a * b, ...) into
kmalloc_array(a, b, ...) or the array_size() macros (e.g. vmalloc(a *
b) into vmalloc(array_size(a, b)).
Coccinelle was fighting me on several fronts, so I've done a bunch of
manual whitespace updates in the patches as well.
Summary:
- Error path bug fix for overflow tests (Dan)
- Additional struct_size() conversions (Matthew, Kees)
- Explicitly reported overflow fixes (Silvio, Kees)
- Add missing kvcalloc() function (Kees)
- Treewide conversions of allocators to use either 2-factor argument
variant when available, or array_size() and array3_size() as needed
(Kees)"
* tag 'overflow-v4.18-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (26 commits)
treewide: Use array_size in f2fs_kvzalloc()
treewide: Use array_size() in f2fs_kzalloc()
treewide: Use array_size() in f2fs_kmalloc()
treewide: Use array_size() in sock_kmalloc()
treewide: Use array_size() in kvzalloc_node()
treewide: Use array_size() in vzalloc_node()
treewide: Use array_size() in vzalloc()
treewide: Use array_size() in vmalloc()
treewide: devm_kzalloc() -> devm_kcalloc()
treewide: devm_kmalloc() -> devm_kmalloc_array()
treewide: kvzalloc() -> kvcalloc()
treewide: kvmalloc() -> kvmalloc_array()
treewide: kzalloc_node() -> kcalloc_node()
treewide: kzalloc() -> kcalloc()
treewide: kmalloc() -> kmalloc_array()
mm: Introduce kvcalloc()
video: uvesafb: Fix integer overflow in allocation
UBIFS: Fix potential integer overflow in allocation
leds: Use struct_size() in allocation
Convert intel uncore to struct_size
...
I noticed a memory corruption crash in nfsd in
4.17-rc1. This patch corrects the issue.
Fix to return error if the delegation couldn't be hashed or there was
a recall in progress. Use the existing error path instead of
destroy_delegation() for readability.
Signed-off-by: Andrew Elble <aweits@rit.edu>
Fixes: 353601e7d3 ("nfsd: create a separate lease for each delegation")
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
fs/nfsd/nfs4state.c:926:8-9: WARNING: return of 0/1 in function 'nfs4_delegation_exists' with return type bool
fs/nfsd/nfs4state.c:2955:9-10: WARNING: return of 0/1 in function 'nfsd4_compound_in_session' with return type bool
Return statements in functions returning bool should use
true/false instead of 1/0.
Generated by: scripts/coccinelle/misc/boolreturn.cocci
Fixes: 68b18f5294 ("nfsd: make nfs4_get_existing_delegation less confusing")
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
[bfields: also fix -EAGAIN]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Currently we only take one vfs-level delegation (lease) for each file,
no matter how many clients hold delegations on that file.
Let's instead keep a one-to-one mapping between NFSv4 delegations and
VFS delegations. This turns out to be simpler.
There is still a many-to-one mapping of NFS opens to NFS files, and the
delegations on one file are all associated with one struct file. The
VFS can still distinguish between these delegations since we're setting
fl_owner to the struct nfs4_delegation now, not to the shared file.
I'm replacing at least one complicated function wholesale, which I don't
like to do, but I haven't figured out how to do this more incrementally.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Pull some duplicated code into a common helper.
This changes the order in destroy_delegation a little, but it looks to
me like that shouldn't matter.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
For now this makes no difference, as for files having delegations,
there's a one-to-one relationship between an nfs4_file and its
nfs4_delegation.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Every single caller gets the file out of the delegation, so let's do
that once in nfs4_put_deleg_lease.
Plus we'll need it there for other reasons.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
fi_delegees is basically just a reference count on users of
fi_deleg_file, which is cleared when fi_delegees goes to zero. The
fi_deleg_file check here is redundant. Also add an assertion to make
sure we don't have unbalanced puts.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
On x86_64, it's 1152 bytes, so we can avoid wasting 896 bytes each.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
We already send it for v4.1, but RFC7530 also notes that the stateid in
the close reply is bogus.
Always send the special close stateid, even in v4.0 responses. No client
should put any meaning on it whatsoever. For now, we continue to
increment the stateid value, though that might not be necessary either.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
We had some reports of panics in nfsd4_lm_notify, and that showed a
nfs4_lockowner that had outlived its so_client.
Ensure that we walk any leftover lockowners after tearing down all of
the stateids, and remove any blocked locks that they hold.
With this change, we also don't need to walk the nbl_lru on nfsd_net
shutdown, as that will happen naturally when we tear down the clients.
Fixes: 76d348fadf (nfsd: have nfsd4_lock use blocking locks for v4.1+ locks)
Reported-by: Frank Sorenson <fsorenso@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Cc: stable@vger.kernel.org # 4.9
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
There's no point I can see to
stp->st_stid.sc_type = NFS4_CLOSED_STID;
given release_lock_stateid immediately sets sc_type to 0.
That set of sc_type to 0 should be enough to prevent it being used where
we don't want it to be; NFS4_CLOSED_STID should only be needed for
actual open stateid's that are actually closed.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The state of the stid is guaranteed by 2 locks:
- The nfs4_client 'cl_lock' spinlock
- The nfs4_ol_stateid 'st_mutex' mutex
so it is quite possible for the stid to be unhashed after lookup,
but before calling nfsd4_lock_ol_stateid(). So we do need to check
for a zero value for 'sc_type' in nfsd4_verify_open_stid().
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Checuk Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org
Fixes: 659aefb68e "nfsd: Ensure we don't recognise lock stateids..."
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
restart_grace() uses hardcoded init_net.
It can cause to "list_add double add" in following scenario:
1) nfsd and lockd was started in several net namespaces
2) nfsd in init_net was stopped (lockd was not stopped because
it have users from another net namespaces)
3) lockd got signal, called restart_grace() -> set_grace_period()
and enabled lock_manager in hardcoded init_net.
4) nfsd in init_net is started again,
its lockd_up() calls set_grace_period() and tries to add
lock_manager into init_net 2nd time.
Jeff Layton suggest:
"Make it safe to call locks_start_grace multiple times on the same
lock_manager. If it's already on the global grace_list, then don't try
to add it again. (But we don't intentionally add twice, so for now we
WARN about that case.)
With this change, we also need to ensure that the nfsd4 lock manager
initializes the list before we call locks_start_grace. While we're at
it, move the rest of the nfsd_net initialization into
nfs4_state_create_net. I see no reason to have it spread over two
functions like it is today."
Suggested patch was updated to generate warning in described situation.
Suggested-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Prevent the use of the closed (invalid) special stateid by clients.
Signed-off-by: Andrew Elble <aweits@rit.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
From kernel 4.9, my two nfsv4 servers sometimes suffer from
"panic: unable to handle kernel page request"
in posix_unblock_lock() called from nfs4_laundromat().
These panics diseappear if we revert the commit "nfsd: add a LRU list
for blocked locks".
The cause appears to be a typo in nfs4_laundromat(), which is also
present in nfs4_state_shutdown_net().
Cc: stable@vger.kernel.org
Fixes: 7919d0a27f "nfsd: add a LRU list for blocked locks"
Cc: jlayton@redhat.com
Reveiwed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The use of the st_mutex has been confusing the validator. Use the
proper nested notation so as to not produce warnings.
Signed-off-by: Andrew Elble <aweits@rit.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The various functions that call check_stateid_generation() in order
to compare a client-supplied stateid with the nfs4_stid state, usually
need to atomically check for closed state. Those that perform the
check after locking the st_mutex using nfsd4_lock_ol_stateid()
should now be OK, but we do want to fix up the others.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
After taking the stateid st_mutex, we want to know that the stateid
still represents valid state before performing any non-idempotent
actions.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
If we're looking up a new lock state, and the creation fails, then
we want to unhash it, just like we do for OPEN. However in order
to do so, we need to that no other LOCK requests can grab the
mutex until we have unhashed it (and marked it as closed).
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Trivial cleanup to simplify following patch.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
In order to deal with lookup races, nfsd4_free_lock_stateid() needs
to be able to signal to other stateful functions that the lock stateid
is no longer valid. Right now, nfsd_lock() will check whether or not an
existing stateid is still hashed, but only in the "new lock" path.
To ensure the stateid invalidation is also recognised by the "existing lock"
path, and also by a second call to nfsd4_free_lock_stateid() itself, we can
change the type to NFS4_CLOSED_STID under the stp->st_mutex.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
If nfsd4_process_open2() is initialising a new stateid, and yet the
call to nfs4_get_vfs_file() fails for some reason, then we must
declare the stateid closed, and unhash it before dropping the mutex.
Right now, we unhash the stateid after dropping the mutex, and without
changing the stateid type, meaning that another OPEN could theoretically
look it up and attempt to use it.
Reported-by: Andrew W Elble <aweits@rit.edu>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Open file stateids can linger on the nfs4_file list of stateids even
after they have been closed. In order to avoid reusing such a
stateid, and confusing the client, we need to recheck the
nfs4_stid's type after taking the mutex.
Otherwise, we risk reusing an old stateid that was already closed,
which will confuse clients that expect new stateids to conform to
RFC7530 Sections 9.1.4.2 and 16.2.5 or RFC5661 Sections 8.2.2 and 18.2.4.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
If a delegation has been revoked by the server, operations using that
delegation should error out with NFS4ERR_DELEG_REVOKED in the >4.1
case, and NFS4ERR_BAD_STATEID otherwise.
The server needs NFSv4.1 clients to explicitly free revoked delegations.
If the server returns NFS4ERR_DELEG_REVOKED, the client will do that;
otherwise it may just forget about the delegation and be unable to
recover when it later sees SEQ4_STATUS_RECALLABLE_STATE_REVOKED set on a
SEQUENCE reply. That can cause the Linux 4.1 client to loop in its
stage manager.
Signed-off-by: Andrew Elble <aweits@rit.edu>
Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Publishing of net pointer is not safe,
let's use nfs->ns.inum instead
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable nfs4_file.fi_ref is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable nfs4_cntl_odstate.co_odcount is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable nfs4_stid.sc_count is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The spec allows us to return NFS4ERR_SEQ_FALSE_RETRY if we notice that
the client is making a call that matches a previous (slot, seqid) pair
but that *isn't* actually a replay, because some detail of the call
doesn't actually match the previous one.
Catching every such case is difficult, but we may as well catch a few
easy ones. This also handles the case described in the previous patch,
in a different way.
The spec does however require us to catch the case where the difference
is in the rpc credentials. This prevents somebody from snooping another
user's replies by fabricating retries.
(But the practical value of the attack is limited by the fact that the
replies with the most sensitive data are READ replies, which are not
normally cached.)
Tested-by: Olga Kornievskaia <aglo@umich.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Currently our handling of 4.1+ requests without "cachethis" set is
confusing and not quite correct.
Suppose a client sends a compound consisting of only a single SEQUENCE
op, and it matches the seqid in a session slot (so it's a retry), but
the previous request with that seqid did not have "cachethis" set.
The obvious thing to do might be to return NFS4ERR_RETRY_UNCACHED_REP,
but the protocol only allows that to be returned on the op following the
SEQUENCE, and there is no such op in this case.
The protocol permits us to cache replies even if the client didn't ask
us to. And it's easy to do so in the case of solo SEQUENCE compounds.
So, when we get a solo SEQUENCE, we can either return the previously
cached reply or NFSERR_SEQ_FALSE_RETRY if we notice it differs in some
way from the original call.
Currently, we're returning a corrupt reply in the case a solo SEQUENCE
matches a previous compound with more ops. This actually matters
because the Linux client recently started doing this as a way to recover
from lost replies to idempotent operations in the case the process doing
the original reply was killed: in that case it's difficult to keep the
original arguments around to do a real retry, and the client no longer
cares what the result is anyway, but it would like to make sure that the
slot's sequence id has been incremented, and the solo SEQUENCE assures
that: if the server never got the original reply, it will increment the
sequence id. If it did get the original reply, it won't increment, and
nothing else that about the reply really matters much. But we can at
least attempt to return valid xdr!
Tested-by: Olga Kornievskaia <aglo@umich.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
J. Bruce Fields