From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7112A47ECDE; Sat, 12 Sep 2026 13:31:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789219904; cv=none; b=oH3JL/JAFYgef1CM/qjIWO1DW5yb/YxpBg5hqWqWAZveNvE6t0ERhvuv/I5LNdO1VazFOSabSnoLEGMMODpknGdalQSSI6HTnEaXDO5u/VHDX6y0lzaY+gRDiV3L8SqTL2otu6Sp5fYRi37fV9iBtBWbqXWBb9nBeMcvJxVhPVw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789219904; c=relaxed/simple; bh=uX3KFMr+w9VfIThB/OlFCggZaVF8GEkz4mizSsA8MHA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QjVcKFGDS4wQSsf0jYgM2FZF4A6+iGu10u96HFIWAwwcHDrS++4bXkFyU/nN/P8x6qE7IP91cR0mihtkqFPWR48Tm0DH+VgU9QVLmIKXjjh9OZZrXeFXTLT65S66oY2eeQN2AwcU82cmeFR/m5HJNTjFPsCIagI4E7CuQmFFB6g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=FQicdIKo; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="FQicdIKo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E73841F000FF; Sat, 12 Sep 2026 13:31:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789219903; bh=CvNw/7bCvJiGU2PbpZB56NLsyDmZS0roK+T82PXU5lI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=FQicdIKoxWF7Qa5agiiZaQRirdPmsXzJsjYFYcCgHXi2NWo252XkpNtIYxLk9PP7r NxOSZnqxdTF7AK/+hLImGjFDvmPSfSZ46b/J/8Tuovanc4/JMV+6LWnRnF/KE6nW1z RsuyICD+EoJSf2HCyelCO8AmUbGR5tq6lFUgN+p8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jeff Layton , Chuck Lever Subject: [PATCH 6.6 0066/1424] nfsd: initialize copy-notify stateid before publishing it Date: Sat, 12 Sep 2026 08:41:38 +0200 Message-ID: <20260912065608.784933195@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.279695368@linuxfoundation.org> References: <20260912065607.279695368@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeff Layton commit 129643893b79f8a3c6b72045f933fbab5ee424ca upstream. 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. Fixes: 624322f1adc5 ("NFSD add COPY_NOTIFY operation") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Jeff Layton Link: https://patch.msgid.link/20260710-nfsd-testing-v3-4-a0ff7db6aa3e@kernel.org Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/nfs4proc.c | 16 +++++++++------- fs/nfsd/nfs4state.c | 10 +++++++++- 2 files changed, 18 insertions(+), 8 deletions(-) --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -1928,7 +1928,6 @@ nfsd4_copy_notify(struct svc_rqst *rqstp struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id); struct nfs4_stid *stid; struct nfs4_cpntf_state *cps; - struct nfs4_client *clp = cstate->clp; status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh, &cn->cpn_src_stateid, RD_STATE, NULL, @@ -1940,12 +1939,14 @@ nfsd4_copy_notify(struct svc_rqst *rqstp cn->cpn_nsec = 0; status = nfserrno(-ENOMEM); + /* + * The returned cps is published and fully initialized, and carries an + * extra reference for us; drop it once we are done with it. + */ cps = nfs4_alloc_init_cpntf_state(nn, stid); if (!cps) goto out; memcpy(&cn->cpn_cnr_stateid, &cps->cp_stateid.cs_stid, sizeof(stateid_t)); - memcpy(&cps->cp_p_stateid, &stid->sc_stateid, sizeof(stateid_t)); - memcpy(&cps->cp_p_clid, &clp->cl_clientid, sizeof(clientid_t)); /* For now, only return one server address in cpn_src, the * address used by the client to connect to this server. @@ -1954,10 +1955,11 @@ nfsd4_copy_notify(struct svc_rqst *rqstp status = nfsd4_set_netaddr((struct sockaddr *)&rqstp->rq_daddr, &cn->cpn_src->u.nl4_addr); WARN_ON_ONCE(status); - if (status) { - nfs4_put_cpntf_state(nn, cps); - goto out; - } + /* + * Drop our extra reference. The membership reference keeps the entry + * alive for a later inter-server READ, or until the laundromat reaps it. + */ + nfs4_put_cpntf_state(nn, cps); out: nfs4_put_stid(stid); return status; --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -1032,7 +1032,15 @@ struct nfs4_cpntf_state *nfs4_alloc_init /* So a stale list_del_init() before linking is a no-op. */ INIT_LIST_HEAD(&cps->cp_list); cps->cpntf_time = ktime_get_boottime_seconds(); - refcount_set(&cps->cp_stateid.cs_count, 1); + /* + * Fully initialize the entry before nfs4_init_cp_state() publishes it, + * since a concurrent OFFLOAD_CANCEL could then free it. Take an extra + * reference for the caller (dropped with nfs4_put_cpntf_state()). + */ + memcpy(&cps->cp_p_stateid, &p_stid->sc_stateid, sizeof(stateid_t)); + memcpy(&cps->cp_p_clid, &p_stid->sc_client->cl_clientid, + sizeof(clientid_t)); + refcount_set(&cps->cp_stateid.cs_count, 2); if (!nfs4_init_cp_state(nn, &cps->cp_stateid, NFS4_COPYNOTIFY_STID, p_stid)) goto out_free;