kernel/git/stable/linux.git/fs/nfsd, branch linux-rolling-stable

nfsd: reset write verifier on deferred writeback errors

2026-07-04T11:45:08+00:00

commit 2090b05803faab8a9fa62fbff871007862cac1b7 upstream. nfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to detect deferred writeback errors, but neither rotates the server's write verifier (nn->writeverf) when this check fails. Every other durable-storage-failure path in these functions calls commit_reset_write_verifier() before returning an error. The missing rotation means clients holding UNSTABLE write data under the current verifier will COMMIT, receive the unchanged verifier back, and conclude their data is durable — silently dropping data that failed writeback. This violates the UNSTABLE+COMMIT durability contract (RFC 1813 §3.3.7, RFC 8881 §18.32). Add commit_reset_write_verifier() calls at both filemap_check_wb_err() error sites, matching the pattern used by adjacent error paths in the same functions. The helper already filters -EAGAIN and -ESTALE internally, so the calls are unconditionally safe. Reported-by: Chris Mason Fixes: 555dbf1a9aac ("nfsd: Replace use of rwsem with errseq_t") Cc: stable@vger.kernel.org Assisted-by: kres:claude-opus-4-6 Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

nfsd: avoid leaking pre-allocated openowner on unconfirmed retry race

2026-07-04T11:45:08+00:00

commit 57aee7a35bb12753057c5b65d72d1f46c0e95b07 upstream. When find_or_alloc_open_stateowner() encounters an unconfirmed owner, it calls release_openowner() and sets oo = NULL. Control then falls through past the `if (oo)` guard -- which would have freed any pre-allocated `new` -- and unconditionally executes `new = alloc_stateowner(...)`. If `new` was already allocated on a prior iteration, the pointer is silently overwritten and the previous allocation (slab object + owner name buffer) is leaked. This requires a race: two NFSv4.0 OPEN threads with the same owner string, where a concurrent thread inserts a new unconfirmed owner into the hash between retry iterations. The window is narrow but repeatable under adversarial conditions. Fix by adding `goto retry` after `oo = NULL` so the already-allocated `new` is reused on the next iteration rather than overwritten. Reported-by: Chris Mason Fixes: 23df17788c62 ("nfsd: perform all find_openstateowner_str calls in the one place.") Cc: stable@vger.kernel.org Assisted-by: kres:claude-opus-4-6 Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

nfsd: fix dead ACL conflict guard in nfsd4_create

2026-07-04T11:45:08+00:00

commit a60f25a800846ab8e5a13f8a9d05111f2aee55a7 upstream. nfsd4_create() steals create->cr_dpacl/cr_pacl into the local nfsd_attrs via the designated initializer, then immediately sets the source pointers to NULL. The subsequent conflict guard tests the already-nilled source fields, making it permanently dead code: if (create->cr_acl) { if (create->cr_dpacl || create->cr_pacl) /* always false */ When a client encodes both FATTR4_WORD0_ACL and FATTR4_WORD2_POSIX_{DEFAULT,ACCESS}_ACL in the same CREATE fattr bitmap, nfsd4_acl_to_attr() overwrites attrs.na_pacl/na_dpacl without releasing the originals, leaking two posix_acl slab objects per request. Repeated requests cause unbounded slab exhaustion. Fix by checking attrs.na_dpacl/na_pacl (the stolen values) instead of the nilled create->cr_dpacl/cr_pacl, matching the correct pattern already used in nfsd4_setattr(). Reported-by: Chris Mason Assisted-by: kres:claude-opus-4-6 Fixes: d2ca50606f5f ("NFSD: Add support for POSIX draft ACLs for file creation") Cc: stable@vger.kernel.org Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

nfsd: check get_user() return when reading princhashlen

2026-07-04T11:45:08+00:00

commit e186fa1c057f5eccb22afb1e83e34c0627085868 upstream. In __cld_pipe_inprogress_downcall(), the get_user() that reads princhashlen from the userspace cld_msg_v2 buffer does not check its return value. A failing copy leaves princhashlen with uninitialised stack contents, which are then used to drive memdup_user() and stored as princhash.len on the resulting reclaim record. The other get_user() calls in this function all check the return; only this one is missed, which is most likely a copy-paste oversight from when v2 upcalls were introduced. Mirror the existing pattern used a few lines above for namelen. namecopy is declared with __free(kfree) so the early return cleans up the already-allocated buffer automatically. Fixes: 6ee95d1c8991 ("nfsd: add support for upcall version 2") Cc: stable@vger.kernel.org Signed-off-by: Dominik Woźniak Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

nfsd: fix posix_acl leak and ignored error in nfsd4_create_file

2026-07-04T11:45:08+00:00

commit 24c975bbdd564d7d0ad90294bfa69729830345de upstream. nfsd4_create_file() has two bugs in its ACL handling: The return value of nfsd4_acl_to_attr() is silently discarded. When the NFSv4-to-POSIX ACL conversion fails (e.g., -EINVAL for unsupported ACE types), the file is created without any ACL and the client receives NFS4_OK. This violates RFC 7530/8881 which require the server to reject unsupported attributes on CREATE. When start_creating() fails after ACL attributes have been populated in attrs (either via nfsd4_acl_to_attr or via ownership transfer from open->op_dpacl/op_pacl), the function jumps to out_write which skips nfsd_attrs_free(). The posix_acl allocations are leaked. A client can trigger this repeatedly with OPEN(CREATE), ACL attributes, and an invalid filename (e.g., longer than NAME_MAX). Fix both by capturing the nfsd4_acl_to_attr() return value and by changing the early error paths to jump to out instead of out_write. Initialize child to ERR_PTR(-EINVAL) so that end_creating() is safe to call even if start_creating() was never reached. Reported-by: Chris Mason Fixes: 7ab96df840e6 ("VFS/nfsd/cachefiles/ovl: add start_creating() and end_creating()") Cc: stable@vger.kernel.org Assisted-by: kres:claude-opus-4-6 Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

nfsd: fix inverted cp_ttl check in async copy reaper

2026-07-04T11:45:08+00:00

commit 0150459b05490b88b7e7378a31550a9e07b5517c upstream. nfsd4_async_copy_reaper() is supposed to keep completed async copy state around for NFSD_COPY_INITIAL_TTL (10) laundromat ticks so that OFFLOAD_STATUS can report the result, then reap the state once the countdown expires. The TTL predicate is inverted: `if (--copy->cp_ttl)` is true while ticks remain and false when the counter reaches zero. This causes the copy to be reaped on the very first tick (cp_ttl goes from 10 to 9, which is non-zero) instead of after all 10 ticks elapse. Once reaped, OFFLOAD_STATUS returns NFS4ERR_BAD_STATEID because the copy state has already been freed. Fix by negating the test so that cleanup runs when the TTL expires. Fixes: aa0ebd21df9c ("NFSD: Add nfsd4_copy time-to-live") Cc: stable@vger.kernel.org Reported-by: Chris Mason Assisted-by: kres:claude-opus-4-6 Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

nfsd: fix posix_acl leak on SETACL decode failure

2026-07-04T11:45:08+00:00

commit 0853ac544c590880d797b04daa33fcb72b6be0e1 upstream. nfsaclsvc_decode_setaclargs() and nfs3svc_decode_setaclargs() each call nfs_stream_decode_acl() twice, first for NFS_ACL and then for NFS_DFACL. Each successful call transfers ownership of a freshly allocated posix_acl into argp->acl_access or argp->acl_default. If the first call succeeds but the second fails, the decoder returns false and argp->acl_access is left dangling. ACLPROC2_SETACL.pc_release was wired to nfssvc_release_attrstat and ACLPROC3_SETACL.pc_release was wired to nfs3svc_release_fhandle. Both only call fh_put() and have no knowledge of the ACL fields on argp. The posix_acl_release() pairs sat at the out: labels inside nfsacld_proc_setacl() and nfsd3_proc_setacl(), but svc_process() skips pc_func when pc_decode returns false, so that cleanup is unreachable on decode failure: svc_process_common() pc_decode() /* decode_setaclargs: false */ /* pc_func skipped */ pc_release() /* fh_put only -- ACLs leaked */ The orphaned posix_acl is leaked for the lifetime of the server. Fix by adding nfsaclsvc_release_setacl() and nfs3svc_release_setacl(), which release both argp->acl_access and argp->acl_default in addition to fh_put(), and wiring them as pc_release for their respective SETACL procedures. pc_release runs on every path svc_process() takes after decode, including decode failure, so the posix_acl_release() pairs are removed from the proc functions' out: labels to keep ownership in one place. This matches the existing release_getacl() pattern used by the sibling GETACL procedures. Fixes: a257cdd0e217 ("[PATCH] NFSD: Add server support for NFSv3 ACLs.") Cc: stable@vger.kernel.org Assisted-by: kres:claude-opus-4-7 Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

NFSD: Fix SECINFO_NO_NAME decode error cleanup

2026-07-04T11:45:08+00:00

commit 9e18e83b8846a5c3fe13fc8a464b4865d33996c6 upstream. nfsd4_decode_secinfo_no_name() currently initializes sin_exp after decoding sin_style. If the XDR stream is truncated, the decoder returns nfserr_bad_xdr before sin_exp is initialized. Since commit 3fdc54646234 ("NFSD: Reduce amount of struct nfsd4_compoundargs that needs clearing"), the inline iops array is not cleared between RPC calls. A failed SECINFO_NO_NAME decode can therefore leave sin_exp holding stale union contents from a previous operation. The error response path still invokes nfsd4_secinfo_no_name_release(), which calls exp_put() on a non-NULL sin_exp. Initialize sin_exp before the first failable decode step, matching nfsd4_decode_secinfo(). Fixes: 3fdc54646234 ("NFSD: Reduce amount of struct nfsd4_compoundargs that needs clearing") Cc: stable@vger.kernel.org Signed-off-by: Guannan Wang Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

nfsd: release layout stid on setlease failure

2026-07-04T11:45:08+00:00

commit 30d55c8aabb261bc3f427d6b9aae7ef6206063f9 upstream. nfs4_alloc_stid() publishes the new stid into cl->cl_stateids via idr_alloc_cyclic() under cl_lock before returning to nfsd4_alloc_layout_stateid(). When nfsd4_layout_setlease() then fails, the error path frees the layout stateid directly with kmem_cache_free() without ever calling idr_remove(), leaving the IDR slot pointing at freed slab memory. Any subsequent IDR walker (states_show, client teardown) dereferences the dangling pointer. The correct teardown for an IDR-published stid is nfs4_put_stid(), which removes the IDR slot under cl_lock, dispatches sc_free (nfsd4_free_layout_stateid) to release ls->ls_file via nfsd4_close_layout(), and drops the nfs4_file reference in its tail. A second issue blocks that switch: nfsd4_free_layout_stateid() unconditionally inspects ls->ls_fence_work via delayed_work_pending() under ls_lock, but INIT_DELAYED_WORK(&ls->ls_fence_work, ...) currently runs only after the setlease call. On the setlease-failure path the destructor would touch an uninitialized delayed_work. nfsd4_alloc_layout_stateid() nfs4_alloc_stid() /* idr_alloc_cyclic under cl_lock */ nfsd4_layout_setlease() /* fails */ nfs4_put_stid() nfsd4_free_layout_stateid() delayed_work_pending(&ls->ls_fence_work) /* needs INIT */ nfsd4_close_layout() /* nfsd_file_put(ls->ls_file) */ put_nfs4_file() Fix by hoisting the ls_fenced / ls_fence_delay / INIT_DELAYED_WORK initialization above the nfsd4_layout_setlease() call, and replace the manual nfsd_file_put + put_nfs4_file + kmem_cache_free cleanup with a single nfs4_put_stid(stp). Fixes: c5c707f96fc9 ("nfsd: implement pNFS layout recalls") Cc: stable@vger.kernel.org Assisted-by: kres (claude-opus-4-7) Signed-off-by: Chris Mason Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

Revert "NFSD: Defer sub-object cleanup in export put callbacks"

2026-06-27T10:08:17+00:00

commit 516403d4d85607fdef3ca41d4a56b54e5566fa9a upstream. This reverts commit 48db892356d6cb80f6942885545de4a6dd8d2a29. Commit 48db892356d6 ("NFSD: Defer sub-object cleanup in export put callbacks") moved path_put() and auth_domain_put() out of svc_export_put() and expkey_put() and behind queue_rcu_work() to close a claimed use-after-free in e_show() and c_show() against ex_path and ex_client->name. Discussion in [1] shows neither the diagnosis nor the remedy survives review. The downstream teardown of both sub-objects is already RCU-deferred. auth_domain_put() reaches svcauth_unix_domain_release(), which frees the unix_domain and its ->name through call_rcu(). path_put() reaches dentry_free(), which frees the dentry through call_rcu(), and prepend_path() is already structured to tolerate concurrent dentry teardown. A reader in cache_seq_start_rcu() therefore observes both sub-objects through the next grace period regardless of whether svc_export_put() runs synchronously, so the synchronous form was never unsafe. The crash signature in the report cited by commit 48db892356d6 ("NFSD: Defer sub-object cleanup in export put callbacks") has a different root cause: a /proc/net/rpc cache file held open across network-namespace exit lets cache_destroy_net() free cd->hash_table while a reader is still walking it. The correct fix pins cd->net for the open fd's lifetime and does not require any deferral inside svc_export_put(). Meanwhile, deferring path_put() out of svc_export_put() reintroduces the regression that commit 69d803c40ede ("nfsd: Revert "nfsd: release svc_expkey/svc_export with rcu_work"") repaired: after "exportfs -r" drops the last cache reference, the mount reference held through ex_path lingers in the workqueue, so a subsequent umount fails with EBUSY. Restore the synchronous path_put() and auth_domain_put() in svc_export_put() and expkey_put() and the call_rcu()/kfree_rcu() free of the containing structures. The unrelated fix for ex_uuid/ex_stats from commit 2530766492ec ("nfsd: fix UAF when access ex_uuid or ex_stats") is preserved. Link: https://lore.kernel.org/all/10019b42-4589-4f9f-8d5b-d8197db1ce3c@huawei.com/ [1] Fixes: 48db892356d6 ("NFSD: Defer sub-object cleanup in export put callbacks") Cc: stable@vger.kernel.org Reviewed-by: Jeff Layton Tested-by: Alexandr Alexandrov Signed-off-by: Yang Erkun Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman