From nobody Sun Feb 8 06:56:14 2026 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) (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 2EA421EDA04; Tue, 13 May 2025 07:24:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.255 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747121070; cv=none; b=tnIdjrSfXiG/zqRRQ3KzcsmWKgObz2SP4RD6SiEC6K7vHOkk0PtIPiv8SPRq7nY9Ju/CWonCt35bOeL4IDATyupZYUUIXqRjyNvNWUmefXD5+9rSaANq3Lui/Ko25lA06RxrZLGqcq9yoIdGIdAXRCMs4dGvxWJPPu9UMbd1sFs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747121070; c=relaxed/simple; bh=8ygg5+lbmN/VLtz/D714USCmypSOCh9GpoUadQ03tCs=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=H5xu/zji49G9lftEECXAxBciG6RUyj1sOYkQXmWzVqZtNpZBrvQGkq+es4x2SJYS17/YB6XRb1zGh3ul+BNHSxQhtIWoarnGoHd1C2N55ZBK4Hg0Mmg560eC3fZk8RHHKezRFu5CLqWPYdx02OB/5h2C3sGuMQWzk1OV/YYlEdM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.255 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.162.254]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4ZxScH0Gq5z1d1JV; Tue, 13 May 2025 15:22:55 +0800 (CST) Received: from kwepemg500017.china.huawei.com (unknown [7.202.181.81]) by mail.maildlp.com (Postfix) with ESMTPS id A5DAF180477; Tue, 13 May 2025 15:24:19 +0800 (CST) Received: from huawei.com (10.175.127.227) by kwepemg500017.china.huawei.com (7.202.181.81) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Tue, 13 May 2025 15:24:18 +0800 From: Li Lingfeng To: , , , , , , CC: , , , , , , , Subject: [PATCH] nfsd: Invoke tracking callbacks only after initialization is complete Date: Tue, 13 May 2025 15:43:05 +0800 Message-ID: <20250513074305.3362209-1-lilingfeng3@huawei.com> X-Mailer: git-send-email 2.31.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemg500017.china.huawei.com (7.202.181.81) Content-Type: text/plain; charset="utf-8" Checking whether tracking callbacks can be called based on whether nn->client_tracking_ops is NULL may lead to callbacks being invoked before tracking initialization completes, causing resource access violations (UAF, NULL pointer dereference). Examples: 1) nfsd4_client_tracking_init // set nn->client_tracking_ops nfsd4_cld_tracking_init nfs4_cld_state_init nn->reclaim_str_hashtbl =3D kmalloc_array ... // error path, goto err nfs4_cld_state_shutdown kfree(nn->reclaim_str_hashtbl) write_v4_end_grace nfsd4_end_grace nfsd4_record_grace_done nfsd4_cld_grace_done nfs4_release_reclaim nn->reclaim_str_hashtbl[i] // UAF // clear nn->client_tracking_ops 2) nfsd4_client_tracking_init // set nn->client_tracking_ops nfsd4_cld_tracking_init write_v4_end_grace nfsd4_end_grace nfsd4_record_grace_done nfsd4_cld_grace_done alloc_cld_upcall cn =3D nn->cld_net spin_lock // cn->cn_lock // NULL deref // error path, skip init pipe __nfsd4_init_cld_pipe cn =3D kzalloc nn->cld_net =3D cn // clear nn->client_tracking_ops After nfsd mounts, users can trigger grace_done callbacks via /proc/fs/nfsd/v4_end_grace. If resources are uninitialized or freed in error paths, this causes access violations. Instead of adding locks for specific resources(e.g., reclaim_str_hashtbl), introducing a flag to indicate whether tracking initialization has completed and checking this flag before invoking callbacks may be better. Fixes: 52e19c09a183 ("nfsd: make reclaim_str_hashtbl allocated per net") Signed-off-by: Li Lingfeng --- fs/nfsd/netns.h | 1 + fs/nfsd/nfs4recover.c | 13 +++++++++---- 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h index 3e2d0fde80a7..dbd782d6b063 100644 --- a/fs/nfsd/netns.h +++ b/fs/nfsd/netns.h @@ -113,6 +113,7 @@ struct nfsd_net { =20 struct file *rec_file; bool in_grace; + bool client_tracking_init_done; const struct nfsd4_client_tracking_ops *client_tracking_ops; =20 time64_t nfsd4_lease; diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c index c1d9bd07285f..6c27c1252c0e 100644 --- a/fs/nfsd/nfs4recover.c +++ b/fs/nfsd/nfs4recover.c @@ -2096,7 +2096,11 @@ nfsd4_client_tracking_init(struct net *net) pr_warn("NFSD: Unable to initialize client recovery tracking! (%d)\n", s= tatus); pr_warn("NFSD: Is nfsdcld running? If not, enable CONFIG_NFSD_LEGACY_CLI= ENT_TRACKING.\n"); nn->client_tracking_ops =3D NULL; + nn->client_tracking_init_done =3D false; + } else { + nn->client_tracking_init_done =3D true; } + return status; } =20 @@ -2105,6 +2109,7 @@ nfsd4_client_tracking_exit(struct net *net) { struct nfsd_net *nn =3D net_generic(net, nfsd_net_id); =20 + nn->client_tracking_init_done =3D false; if (nn->client_tracking_ops) { if (nn->client_tracking_ops->exit) nn->client_tracking_ops->exit(net); @@ -2117,7 +2122,7 @@ nfsd4_client_record_create(struct nfs4_client *clp) { struct nfsd_net *nn =3D net_generic(clp->net, nfsd_net_id); =20 - if (nn->client_tracking_ops) + if (nn->client_tracking_ops && nn->client_tracking_init_done) nn->client_tracking_ops->create(clp); } =20 @@ -2126,7 +2131,7 @@ nfsd4_client_record_remove(struct nfs4_client *clp) { struct nfsd_net *nn =3D net_generic(clp->net, nfsd_net_id); =20 - if (nn->client_tracking_ops) + if (nn->client_tracking_ops && nn->client_tracking_init_done) nn->client_tracking_ops->remove(clp); } =20 @@ -2135,7 +2140,7 @@ nfsd4_client_record_check(struct nfs4_client *clp) { struct nfsd_net *nn =3D net_generic(clp->net, nfsd_net_id); =20 - if (nn->client_tracking_ops) + if (nn->client_tracking_ops && nn->client_tracking_init_done) return nn->client_tracking_ops->check(clp); =20 return -EOPNOTSUPP; @@ -2144,7 +2149,7 @@ nfsd4_client_record_check(struct nfs4_client *clp) void nfsd4_record_grace_done(struct nfsd_net *nn) { - if (nn->client_tracking_ops) + if (nn->client_tracking_ops && nn->client_tracking_init_done) nn->client_tracking_ops->grace_done(nn); } =20 --=20 2.31.1