| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix dentry ref leak on V4ROOT export filehandle lookup
nfsd_set_fh_dentry() leaks the dentry reference from
exportfs_decode_fh_raw() when the NFS3_FHSIZE or NFS_FHSIZE
switch cases detect NFSEXP_V4ROOT and goto out. The out: label
calls exp_put() but never dput(dentry), and fhp->fh_dentry was
never assigned so fh_put() cannot compensate.
A crafted NFSv3 filehandle targeting a V4ROOT export's fsid
triggers the leak on every request. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net
nfsd_file_dispose_list_delayed() defers fput() to nfsd service threads
via a per-net freeme queue, preventing the shrinker and GC worker from
bearing the cost of closing files (see ffb402596147). However, the
queue lives in a separately-allocated struct nfsd_fcache_disposal that
is freed by nfsd_free_fcache_disposal_net() during per-net teardown.
The global shrinker, laundrette, and fsnotify callbacks can still be
inside nfsd_file_dispose_list_delayed() dereferencing that pointer,
causing a use-after-free.
Inline the spinlock and freeme list directly into struct nfsd_net (as
fcache_dispose_lock and fcache_dispose_list), eliminating the separately
allocated struct nfsd_fcache_disposal entirely. These fields now have
the same lifetime as the net namespace itself, so there is no dangling
pointer to chase.
nfsd_file_cache_start_net() now just initializes the inline fields and
cannot fail due to allocation. nfsd_file_cache_shutdown_net() drains
the inline list directly instead of freeing a separate struct. The
alloc/free helpers are removed. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix nfsd_file leak on inter-server COPY setup failure
When nfsd4_setup_inter_ssc() fails, nfsd4_copy() returns
nfserr_offload_denied directly, bypassing the out: label where
release_copy_files() would drop the nf_dst reference taken by
nfs4_preprocess_stateid_op(). Each failed inter-server COPY
leaks one nfsd_file, pinning file/inode/dentry/vfsmount.
Fix by setting status and jumping to out: instead of returning
directly. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix null dereference in nfsd4_setattr for deleg timestamp attrs
When a SETATTR request includes FATTR4_WORD2_TIME_DELEG_ACCESS or
FATTR4_WORD2_TIME_DELEG_MODIFY in the attribute bitmap, nfsd4_setattr()
sets deleg_attrs=true and calls nfs4_preprocess_stateid_op() to validate
the stateid.
If the client supplies the NFSv4 "one stateid" (all-0xFF bytes),
check_special_stateids() returns nfs_ok without populating the output
nfs4_stid pointer, because the special-stateid path in
nfs4_preprocess_stateid_op() jumps to done: with s==NULL, and the
"if (s)" block that would set *cstid is skipped. The local variable `st`
remains NULL.
Back in nfsd4_setattr(), the if (deleg_attrs) block then unconditionally
dereferences st->sc_type (at offset 4 from NULL), causing a kernel oops.
This is remotely triggerable by any NFSv4 client: send COMPOUND [PUTROOTFH,
SETATTR(ONE_STATEID, {bmval2=FATTR4_WORD2_TIME_DELEG_ACCESS, ...})].
No authentication, delegation, or prior state is required.
Fix by adding a NULL check before the dereference. A special stateid is
not a delegation stateid, so the existing nfserr_bad_stateid return value
is already correct; we only need to guard the pointer dereference itself. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix partial-write detection in nfsd_direct_write
nfsd_direct_write() walks a list of write segments and, after each
vfs_iocb_iter_write(), tries to detect a short write so the loop can
stop before placing the next segment at a wrong file offset:
host_err = vfs_iocb_iter_write(file, kiocb, &segments[i].iter);
if (host_err < 0)
return host_err;
*cnt += host_err;
if (host_err < segments[i].iter.count)
break; /* partial write */
vfs_iocb_iter_write() runs the iter through ->write_iter(), which
advances the iter by the number of bytes written. By the time the
check runs, segments[i].iter.count is the residual, not the original
request length:
before write_iter: iter.count == original_len
after write_iter: iter.count == original_len - host_err
The condition then reduces to host_err < original_len - host_err, so
the break fires only when less than half of the segment was written.
Any short write completing between 50% and 99% of the segment slips
through; the loop advances to the next segment with kiocb->ki_pos
only bumped by the short amount, writing the next segment's payload
at the wrong offset and over-reporting *cnt to the NFS client.
Snapshot the segment's byte count before the write and compare
host_err against that snapshot so any short write breaks the loop. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix stale s2s_cp_stateids IDR entry for async COPY
For an async COPY, nfsd4_copy() called nfs4_init_copy_state() before
dup_copy_fields(), so the s2s_cp_stateids IDR was pointed at
&u->copy->cp_stateid -- memory in the per-rqstp COMPOUND buffer that is
reused by the next request. dup_copy_fields() copies only the value into
async_copy, so the IDR slot dangled at the transient buffer for the whole
background copy. Any IDR walker then dereferences reused request memory:
the laundromat reads cs_type from it and, if the bytes look like an
expired NFS4_COPYNOTIFY_STID, follows into
refcount_dec()/idr_remove()/kfree() on garbage; manage_cpntf_state() has
the same exposure via idr_find().
Duplicate the fields first, then register the stateid on the stable
async_copy. result->cb_stateid is unchanged. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix UAF in async copy cancel and shutdown
An async copy could be freed or used after free while a teardown caller
(OFFLOAD_CANCEL, nfsd4_shutdown_copy, nfsd4_cancel_copy_by_sb) raced the
copy kthread:
- find_async_copy() bumped copy->refcount but left the copy on
clp->async_copies, so the reaper's cleanup_async_copy() could run
release_copy_files() concurrently with a cancel/shutdown caller. Both
put and NULL nf_src/nf_dst without a common lock, double-putting the
nfsd_file and freeing it early.
- nfsd4_do_async_copy() set NFSD4_COPY_F_STOPPED before its final uses
of the copy (nfsd_update_cmtime_attr() on copy->nf_dst,
nfsd4_send_cb_offload()). nfsd4_stop_copy() treats a set STOPPED bit
as "kthread done, skip kthread_stop()", so a teardown caller ran
release_copy_files() -- which puts and NULLs nf_dst -- while the
kthread still dereferenced it (NULL/UAF).
- copy->copy_task was never pinned. The one-shot kthread self-reaps on
return, so kthread_stop()'s get_task_struct() could touch a freed
task_struct.
- co_cb is embedded in the copy, but nfsd4_send_cb_offload() held a
reference only on the client, so a concurrent teardown could free
the copy while the CB_OFFLOAD callback was in flight.
Fix the teardown lifetime as a whole:
- find_async_copy() unlinks the copy (clear cp_clp, list_del_init)
under async_lock; the cancel, shutdown, and sb-cancel paths drop the
list-membership reference via nfs4_put_copy() after nfsd4_stop_copy().
Drop the now-redundant list_del fixup from cleanup_async_copy().
- Because unlinking hides the copy from the reaper, its
cleanup_async_copy() can no longer remove the copy's s2s_cp_stateids
entry; the cancel/shutdown/sb-cancel paths now call
nfs4_free_copy_state() themselves (while cp_clp is still valid) so
the entry does not dangle at freed memory for the laundromat and
manage_cpntf_state() to dereference.
- Give the kthread its own reference, taken in nfsd4_copy() before
wake_up_process() and dropped at the end of nfsd4_do_async_copy();
call wake_up_process() before list_add().
- Pin the task_struct with get_task_struct() in nfsd4_copy(), released
in nfs4_put_copy(), so kthread_stop() is safe whenever the kthread
exits. Set NFSD4_COPY_F_STOPPED only in nfsd4_stop_copy(), which now
always kthread_stop()s before release_copy_files(); completion is
still reported via NFSD4_COPY_F_COMPLETED, so
nfsd4_has_active_async_copies() is unaffected. Each teardown caller
removes the copy from clp->async_copies first, so kthread_stop() runs
exactly once.
- Take a copy reference in nfsd4_send_cb_offload(), dropped in
nfsd4_cb_offload_release(). The kthread still holds its own reference
there, so the refcount_inc() cannot race the final free.
- Read cp_clp with smp_load_acquire() to pair with the unordered
set_bit()/clear_bit() writers (Documentation/atomic_bitops.rst). |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix XDR padding calculation in ff_encode_getdeviceinfo
nfsd4_ff_encode_getdeviceinfo() computes the da_addr_body reservation
as 16 + netid_len + addr_len, but the subsequent xdr_encode_opaque()
calls emit 8 + round_up(netid_len, 4) + round_up(addr_len, 4) bytes.
The mismatch means the declared da_addr_body length exceeds the actual
encoded data by 2-8 bytes on every flexfile GETDEVICEINFO reply,
leaking stale reply-page content to the client and mis-aligning the
subsequent version list decode.
Use xdr_align_size() for each string length to match what
xdr_encode_opaque() actually writes. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: hold rcu across localio cmpxchg retry
nfsd_file objects are freed via call_rcu (filecache.c:296), and
nfsd_file_slab is created without SLAB_TYPESAFE_BY_RCU
(KMEM_CACHE(nfsd_file, 0) at filecache.c:789), so the slab page
backing a freed nfsd_file becomes freely reclaimable once the RCU
grace period elapses.
The again: retry block in nfsd_open_local_fh() loads a pointer with
cmpxchg and then calls nfsd_file_get(new) (which is
refcount_inc_not_zero) without holding rcu_read_lock. The sole caller
nfs_open_local_fh() drops rcu_read_lock before invoking this helper,
so no outer reader-side critical section covers the load.
CPU 0 (nfsd_open_local_fh) CPU 1 (nfsd_file_put_local)
----- -----
new = cmpxchg(pnf, NULL, ...)
nf = xchg(pnf, NULL)
nfsd_file_put(nf)
last ref -> call_rcu()
/* grace period elapses;
slab page recycled */
nfsd_file_get(new)
refcount_inc_not_zero(&new->nf_ref)
/* operates on recycled memory */
A non-zero word at the nf_ref offset of the recycled object makes the
refcount bump appear to succeed, and the caller then dereferences
new->nf_net and new->nf_file out of freed memory.
Fix by taking rcu_read_lock() immediately before the cmpxchg and
releasing it on all three exits of the if (new) block: the goto-again
retry, the lost-race cleanup path, and the install-succeeded path.
nfsd_file_put() and nfsd_net_put() stay outside the RCU section so
they remain free to block. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: initialize copy-notify stateid before publishing it
nfsd4_copy_notify() finished initializing the cpntf state after
nfs4_alloc_init_cpntf_state() had already linked it into the
s2s_cp_stateids IDR and the parent's sc_cp_list, with cs_count == 1 (the
membership reference) and none held for the caller. A racing
OFFLOAD_CANCEL (crafted cl_id == nn->s2s_cp_cl_id plus the guessable
so_id) could reach manage_cpntf_state() and free the entry, turning the
caller's subsequent cpn_cnr_stateid read and cp_p_stateid/cp_p_clid
writes into use-after-free. The owning clientid was also only recorded
after publication, so it could not gate an ownership check in that window.
Record cp_p_stateid and cp_p_clid inside nfs4_alloc_init_cpntf_state()
before nfs4_init_cp_state() publishes the entry, and return it with an
extra reference. The caller reads the stateid under that reference and
drops it with nfs4_put_cpntf_state(); on a late error the laundromat
reaps the entry. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: close shrinker/GC/fsnotify vs per-net shutdown race in filecache
The shrinker, GC worker, and fsnotify/lease callbacks can unhash an
nfsd_file from the rhashtable and then call
nfsd_file_dispose_list_delayed() to move it to the per-net dispose list.
If nfsd_file_cache_shutdown_net() runs concurrently, its rhashtable walk
misses the already-unhashed file, and its drain of the per-net dispose
list can run before the file has been queued. The file then sits on
the per-net list with no thread to drain it, leaking both the file and
its associated state.
The GC worker and shrinker already hold nfsd_gc_lock while walking the
LRU, but in the original code they release it before calling
nfsd_file_dispose_list_delayed(). The fsnotify/lease path
(nfsd_file_close_inode) has no synchronization at all.
Fix this by:
1. Widening nfsd_gc_lock in both nfsd_file_gc() and nfsd_file_lru_scan()
to cover the nfsd_file_dispose_list_delayed() call.
2. Wrapping nfsd_file_close_inode() in nfsd_gc_lock so that all three
callers of nfsd_file_dispose_list_delayed() hold the lock.
3. Adding a spin_lock/unlock(nfsd_gc_lock) barrier in
nfsd_file_cache_shutdown_net() after the purge, so that any
in-progress disposal has fully completed before the per-net list
is drained.
All operations inside the lock are non-sleeping (rhashtable lookups,
atomic bit/refcount ops, list moves, svc_wake_up), so the spinlock is
appropriate. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: revoke copy-notify stateids before dropping their reference
Copy-notify stateids live in the s2s_cp_stateids IDR and on their parent
stid's sc_cp_list, pinned by a single membership reference.
_free_cpntf_state_locked() only unlinks an entry once its refcount reaches
zero, so any revoke path that runs while a concurrent
find_cpntf_state()/manage_cpntf_state() holder has elevated cs_count drops
the reference without unlinking, leaving the entry discoverable with its
membership reference already consumed. A second revoke or a laundromat tick
then frees it while the reader still holds the pointer -- a
KASAN-detectable use-after-free at the reader's nfs4_put_cpntf_state().
This affected all three revoke paths:
- The parent-stid drain (nfs4_free_cpntf_statelist()) repeatedly called
_free_cpntf_state_locked() on the first list entry; a holder that had
bumped cs_count made it return early, so the next iteration
re-decremented and burned the holder's reference.
- OFFLOAD_CANCEL (manage_cpntf_state()) and laundromat expiry likewise
used _free_cpntf_state_locked() and could drop 2->1 without unlinking.
Add revoke_cpntf_state_locked(), which unhashes the entry from the IDR and
sc_cp_list first (deferring the final free to any holder), and use it from
all three revoke paths. The drain now walks with list_for_each_entry_safe()
and revokes each entry unconditionally, so it terminates in one pass per
entry regardless of cs_count. The unhash is gated on
!list_empty(&cps->cp_list); the idr_remove() gate matters because
idr_alloc_cyclic() may have recycled the so_id by then. Keep
_free_cpntf_state_locked() for the reference-holder put path only, where a
concurrent revoke may already have unlinked the entry (its list_del_init()
then a no-op). |
| In the Linux kernel, the following vulnerability has been resolved:
NFSD: Prevent post-shutdown use-after-free in unlock_filesystem
Writing a filesystem path to /proc/fs/nfsd/unlock_filesystem runs
nfsd4_cancel_copy_by_sb() before nfsd_mutex is held and before the
handler confirms that nn->nfsd_serv is set. Once nfsd has shut down,
nfs4_state_destroy_net() has freed nn->conf_id_hashtbl but left the
pointer intact, so the cancel helper iterates freed slab memory as an
array of struct list_head and then dereferences a bogus nfs4_client
when it takes clp->async_lock. A local administrator holding
CAP_SYS_ADMIN can reach this use-after-free by stopping the server and
then writing to unlock_filesystem; KASAN reports a slab-use-after-free
read in nfsd4_cancel_copy_by_sb().
nfsd4_revoke_states() walks the same state tables and for that reason
already runs only under nfsd_mutex with nn->nfsd_serv confirmed
present. Move the async COPY cancel into that protected section so
every NFSv4 state-table walker on this path observes a running server.
Async copies exist only while the server runs, so gating the cancel on
nn->nfsd_serv loses nothing. |
| In the Linux kernel, the following vulnerability has been resolved:
NFSD: Prevent client use-after-free during admin state revocation
A stateid holds only a bare pointer to its nfs4_client; a stateid
reference does not pin it. The client survives only because
__destroy_client() drains its stateids before free_client() runs.
nfsd4_revoke_states() drops nn->client_lock across revoke_one_stid(),
which dereferences the client to revoke a stateid and read
clp->cl_minorversion. A teardown racing the dropped lock can free
the client first.
Pinning cl_rpc_users under client_lock blocks the DESTROY_CLIENTID and
EXCHANGE_ID teardown, which refuses while cl_rpc_users is non-zero.
force_expire_client() ignores it: once its wait for cl_rpc_users to
reach zero has passed, a later pin goes unnoticed.
Under client_lock, skip a client whose cl_time is already zero --
force_expire_client() clears it there before waiting -- otherwise pin
cl_rpc_users before dropping the lock. The walk then either sees the
expiry and skips, or pins in time for that wait to cover the revoke. |
| In the Linux kernel, the following vulnerability has been resolved:
NFSD: Prevent client use-after-free during delegation revoke
A delegation stateid holds only a bare pointer to its owning
nfs4_client and does not keep it alive. The client survives its
stateids only because __destroy_client() drains cl_delegations and
cl_revoked before free_client() runs.
nfs4_laundromat() breaks that invariant: it unhashes an
expired delegation from cl_delegations, drops deleg_lock, then
revoke_delegation() relinks it onto cl_revoked under cl_lock. In that
window the delegation is on neither list, so client_has_state() can
report no remaining state.
Every teardown path first requires cl_rpc_users to be zero, but
the laundromat holds no such reference. A client whose recalled
delegation has just timed out can therefore reach free_client()
while revoke_delegation() is still about to dereference cl_lock,
a use-after-free.
Pin the client with cl_rpc_users across the revoke so teardown blocks
until it completes, then reap the delegation from cl_revoked. A client
already expiring reaps its own, so skip it and leave the delegation on
del_recall_lru. |
| In the Linux kernel, the following vulnerability has been resolved:
NFSD: Prevent client use-after-free during NFSv4.0 revoked-state cleanup
nfs40_clean_admin_revoked() takes a stateid reference under
clp->cl_lock, drops nn->client_lock, and calls
nfsd4_drop_revoked_stid(), which dereferences the stateid's client
through s->sc_client->cl_lock. The stateid reference does not pin the
client, so a teardown racing the dropped lock can free the client
while nfsd4_drop_revoked_stid() is still using it.
This cleanup runs from the laundromat, so a periodic sweep can race
force_expire_client() driven by a write to the clients/<id>/ctl file.
Skip a client that is already expiring and otherwise pin it with
cl_rpc_users under client_lock before dropping the lock, matching
nfsd4_revoke_states(). |
| In the Linux kernel, the following vulnerability has been resolved:
libceph: validate OSD extent maps before cursor advance
net/ceph/osd_client.c:osd_sparse_read() validates that the sparse-read
data length matches the summed extent lengths, but it does not validate
that each OSD-supplied extent is monotonic and lies inside the original
request range. A malformed authenticated OSD reply can advertise a
far-forward nonzero extent offset with a matching data length and make
the client advance the message-data cursor beyond the request buffer.
This reaches the BUG_ON(!*length) assertion in ceph_msg_data_next() from
the client receive path.
Impact: A malicious or compromised authenticated Ceph OSD peer can crash
a kernel Ceph client via a malformed sparse-read reply.
Reject sparse extent maps that overflow, move backwards, overlap, or
extend outside the original sparse-read request before advancing the
cursor.
[ idryomov: perform sparse_extent_map_valid() check a bit earlier,
in CEPH_SPARSE_READ_DATA_LEN instead of CEPH_SPARSE_READ_DATA_PRE
state ] |
| In the Linux kernel, the following vulnerability has been resolved:
ceph: fix UAF in __kick_flushing_caps() on cf entry freed during unlock
list_for_each_entry() iterates ci->i_cap_flush_list but drops
i_ceph_lock to send cap messages. During the unlock window,
handle_cap_flush_ack() can acquire i_ceph_lock, detach cf entries
with tid <= flush_tid from the list, release i_ceph_lock, and free
them via ceph_free_cap_flush() outside any lock. When the original
thread reacquires i_ceph_lock and the for-loop macro advances via
cf = list_next_entry(cf, i_list), it dereferences cf->i_list.next
on freed memory.
The race timeline:
__kick_flushing_caps() handle_cap_flush_ack()
----------------------- -----------------------
holds i_ceph_lock <---
iterates to cf (tid=10)
prepares FLUSH message
drops i_ceph_lock <---
__send_cap() ── FLUSH(tid=10)
MDS sends FLUSH_ACK(tid=10)
---> acquires i_ceph_lock
cf->tid(10) <= flush_tid(10),
detaches cf from i_cap_flush_list
drops i_ceph_lock
ceph_free_cap_flush(cf) <- frees it!
acquires i_ceph_lock <---
for-loop advances:
cf = list_next_entry(cf, i_list)
-- UAF on freed cf->i_list.next
The cf was just sent by __kick_flushing_caps itself via __send_cap().
The MDS may respond with FLUSH_ACK quickly enough that
handle_cap_flush_ack() frees cf before __kick_flushing_caps can
finish the iteration.
Fix by converting to a manual while loop: save the next pointer
under i_ceph_lock before dropping it, then use the saved pointer
after reacquiring, so the potentially-freed cf is never accessed again. |
| In the Linux kernel, the following vulnerability has been resolved:
ceph: fix UAF in check_new_map() on session freed during unlock
check_new_map() iterates mdsc->sessions[] and for each active session
drops mdsc->mutex to perform per-session operations. The forced-close
path (rank removed from map) correctly takes a reference on s via
ceph_get_mds_session() before releasing mdsc->mutex, but three other
paths do not:
Path A (address changed): mutex_unlock → mutex_lock(&s->s_mutex)
Path B (reconnect): mutex_unlock → send_mds_reconnect(mdsc, s)
Path C (active transition): mutex_unlock → mutex_lock(&s->s_mutex)
Without the extra reference, another thread can acquire mdsc->mutex
during the unlock window, call __unregister_session() which drops the
last reference on s, and free it. The original thread then accesses
freed memory via s->s_mutex.
Fix by adding ceph_get_mds_session(s) before each mutex_unlock and
ceph_put_mds_session(s) after the corresponding mutex_lock, matching
the pattern already used in the forced-close path.
Race timeline (Path A):
Thread A (check_new_map) Thread B (another map update
holds mdsc->mutex or session teardown)
-------------------------- --------------------------
s = mdsc->sessions[i]
(refcount == 1, held only by
sessions[] array)
mutex_unlock(&mdsc->mutex)
---> acquires mdsc->mutex
__unregister_session(mdsc, s)
sessions[i] = NULL
ceph_put_mds_session(s)
refcount: 1 -> 0
kfree(s) <--- freed!
mutex_lock(&s->s_mutex)
UAF on freed s->s_mutex |
| In the Linux kernel, the following vulnerability has been resolved:
ceph: bound copied dentry name length in NFS export get_name
ceph_get_name() copies the MDS-supplied name into the caller's
NAME_MAX-sized buffer with memcpy(name, rinfo->dname, rinfo->dname_len)
and then writes name[rinfo->dname_len] = 0, without checking dname_len
against NAME_MAX. A malicious or buggy MDS that returns a LOOKUPNAME reply
with dname_len > NAME_MAX overflows the buffer. __get_snap_name() copies
rde->name / rde->name_len the same unchecked way.
Impact: a malicious or compromised Ceph MDS overflows the NAME_MAX name
buffer in a client's NFS-export get_name path, a slab out-of-bounds write
reported by KASAN. Reachable when a CephFS mount is re-exported over NFS.
Add ceph_export_copy_name(), which rejects lengths above NAME_MAX with
-ENAMETOOLONG before the copy, and use it in both ceph_get_name() and
__get_snap_name(). |
