nfsd: fix dentry ref leak on V4ROOT export filehandle lookup
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.
nfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net
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-fre
In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix layout fence worker double-reference race
The workqueue core clears WORK_STRUCT_PENDING before the callback
is invoked, so delayed_work_pending() in lm_breaker_timedout() can
return false while the fence worker is already running. This lets
the breaker take a duplicate sc_count reference and schedule a new
worker that coalesces with the in-progress one. The extra reference
is never put, leaking the layout stateid.
Replace the racy delayed_work_pending() check with an
ls_fence_inflight boolean set atomically with
refcount_inc_not_zero() under ls_lock, and cleared
nfsd: fix nfsd_file leak on inter-server COPY setup failure
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.
nfsd: fix null dereference in nfsd4_setattr for deleg timestamp attrs
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
nfsd: fix partial-write detection in nfsd_direct_write
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 by
nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file()
In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file()
dentry_create() can hypothetically provide a different dentry than the
one passed in. This could happen, for example, if the exported
filesystem is NFS, and the server returned to OPEN a filehandle which
matched a directory that was already in the dcache. Clearly this would
not be expected!
If this were to happen the dentry (child) that was already stored in
resfhp could be freed and later dereferenced.
We shouldn't call fh_compose() until we are certain that we have the
final dentry, so this patch mov
nfsd: fix stale s2s_cp_stateids IDR entry for async COPY
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, fol
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 be
nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget
In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget
The XDR buffer size calculation in nfsd4_ff_encode_layoutget() has
multiple errors that can result in either an out-of-bounds write or
leaking uninitialized kernel memory to the client:
- fh_len doesn't account for XDR padding on the file handle data
- uid and gid lengths use "8 + len" but xdr_encode_opaque() actually
writes "4 + xdr_align_size(len)" bytes
- ds_len omits the flags and stats_collect_hint fields (8 bytes),
while len's header constant overestimates by 8 bytes -- these
partially cancel b
In the Linux kernel, the following vulnerability has been resolved:
nfsd: gate nfs2 setacl by argp->mask
The NFSACL v2 SETACL path shares the decoder convention used by its
v3 sibling: nfsaclsvc_decode_setaclargs() fills in argp->acl_access
only when NFS_ACL is set in the request mask and argp->acl_default
only when NFS_DFACL is set, leaving the other pointer NULL because
the argument buffer is zeroed up to pc_argzero before decode.
nfsacld_proc_setacl() then hands both pointers to set_posix_acl()
unconditionally. set_posix_acl(idmap, dentry, type, NULL) is the VFS
"remove this ACL type" operation, so an omitted arm is
indistinguishable fr
In the Linux kernel, the following vulnerability has been resolved:
nfsd: gate nfs3 setacl by argp->mask
nfsd3_proc_setacl() calls set_posix_acl() unconditionally for both
ACL_TYPE_ACCESS and ACL_TYPE_DEFAULT, passing argp->acl_access and
argp->acl_default verbatim. The NFSv3 ACL decoder only populates
those pointers when the corresponding mask bit is set:
nfs3svc_decode_setaclargs()
if (args->mask & NFS_ACL) decode into acl_access
if (args->mask & NFS_DFACL) decode into acl_default
/* otherwise the pointer stays NULL (pc_argzero) */
nfsd3_proc_setacl()
set_posix_acl(.., ACL_TYPE_ACCESS, argp->acl_acce
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
nfsd: initialize copy-notify stateid before publishing it
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 al
nfsd: move nfsd_debugfs_init() after nfsd4_init_slabs() in init_nfsd()
In the Linux kernel, the following vulnerability has been resolved:
nfsd: move nfsd_debugfs_init() after nfsd4_init_slabs() in init_nfsd()
nfsd_debugfs_init() runs before nfsd4_init_slabs() in init_nfsd().
If the slab allocation fails, the bare "return retval" bypasses
nfsd_debugfs_exit(), leaving orphan debugfs files with stale fops
pointers into the freed module text.
Move nfsd_debugfs_init() to after the slab init succeeds, so the
early return has no debugfs state to clean up.
Since debugfs is now the more recently initialized of the two, also
update the unwind paths to match reverse-initialization (LIFO) order:
run nfsd_debugfs_exit()
nfsd: close shrinker/GC/fsnotify vs per-net shutdown race in filecache
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
nfsd: reject out-of-range nseconds in NFSv3 SETATTR and create ops
In the Linux kernel, the following vulnerability has been resolved:
nfsd: reject out-of-range nseconds in NFSv3 SETATTR and create ops
A client can send an NFSv3 SETATTR, CREATE, MKDIR, SYMLINK or MKNOD
carrying an atime or mtime whose nseconds field is out of range. The
value is well-formed on the wire and decodes cleanly into a valid
uint32, but it is not a valid timespec64: tv_nsec must be less than
NSEC_PER_SEC.
Nothing in the setattr path clamps it. notify_change() runs the time
through timestamp_truncate(), which does not reduce tv_nsec below
NSEC_PER_SEC when the filesystem supports nanosecond granularity
(s_time_gran == 1), and the
nfsd: reject out-of-range useconds in NFSv2 SETATTR/CREATE
In the Linux kernel, the following vulnerability has been resolved:
nfsd: reject out-of-range useconds in NFSv2 SETATTR/CREATE
The NFSv2 sattr decoder converts the wire useconds to nanoseconds in
svcxdr_decode_sattr():
iap->ia_atime.tv_nsec = tmp2 * NSEC_PER_USEC;
tmp2 is a u32 and NSEC_PER_USEC is 1000, so the product is computed in
unsigned long. On ILP32 that is 32 bits, and an out-of-range useconds
value such as 4294968 wraps to tv_nsec == 704. The corruption therefore
happens during decode, before any proc function can inspect the value,
and a later range check on tv_nsec would see an in-range result and
accept it. Rejecting in the
nfsd: release OPEN-decoded posix ACLs via op_release
In the Linux kernel, the following vulnerability has been resolved:
nfsd: release OPEN-decoded posix ACLs via op_release
nfsd4_decode_createhow4() calls nfsd4_decode_fattr4(), which allocates
refcounted struct posix_acl objects via posix_acl_alloc() and stores
them in open->op_pacl and open->op_dpacl. These pointers must be
released once the OPEN compound finishes.
When nfsd4_decode_open_claim4() returns a non-seqid-mutating error,
the dispatcher short-circuits before op_func runs:
nfsd4_proc_compound()
if (op->status && op->opnum == OP_OPEN)
op->status = nfsd4_open_omfg(...)
if (!seqid_mutating_err(ntohl
nfsd: revoke copy-notify stateids before dropping their reference
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 read