From patchwork Fri Oct 20 09:53:36 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Reshetova, Elena" X-Patchwork-Id: 10019417 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5394C60234 for ; Fri, 20 Oct 2017 09:57:08 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4658128EBD for ; Fri, 20 Oct 2017 09:57:08 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3B57128ED4; Fri, 20 Oct 2017 09:57:08 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CF54C28EBD for ; Fri, 20 Oct 2017 09:57:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752814AbdJTJ4F (ORCPT ); Fri, 20 Oct 2017 05:56:05 -0400 Received: from mga02.intel.com ([134.134.136.20]:1670 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752813AbdJTJ4D (ORCPT ); Fri, 20 Oct 2017 05:56:03 -0400 Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Oct 2017 02:56:02 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.43,405,1503385200"; d="scan'208";a="1207992129" Received: from elena-thinkpad-x230.fi.intel.com ([10.237.72.87]) by fmsmga001.fm.intel.com with ESMTP; 20 Oct 2017 02:56:00 -0700 From: Elena Reshetova To: trond.myklebust@primarydata.com Cc: linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, anna.schumaker@netapp.com, bfields@fieldses.org, jlayton@poochiereds.net, peterz@infradead.org, keescook@chromium.org, Elena Reshetova Subject: [PATCH 09/11] fs, nfs: convert nfs4_lock_state.ls_count from atomic_t to refcount_t Date: Fri, 20 Oct 2017 12:53:36 +0300 Message-Id: <1508493218-27760-10-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1508493218-27760-1-git-send-email-elena.reshetova@intel.com> References: <1508493218-27760-1-git-send-email-elena.reshetova@intel.com> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable nfs4_lock_state.ls_count is used as pure reference counter. Convert it to refcount_t and fix up the operations. Suggested-by: Kees Cook Reviewed-by: David Windsor Reviewed-by: Hans Liljestrand Signed-off-by: Elena Reshetova --- fs/nfs/nfs4_fs.h | 2 +- fs/nfs/nfs4proc.c | 6 +++--- fs/nfs/nfs4state.c | 8 ++++---- 3 files changed, 8 insertions(+), 8 deletions(-) diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h index ac4f10b..29409a8 100644 --- a/fs/nfs/nfs4_fs.h +++ b/fs/nfs/nfs4_fs.h @@ -144,7 +144,7 @@ struct nfs4_lock_state { unsigned long ls_flags; struct nfs_seqid_counter ls_seqid; nfs4_stateid ls_stateid; - atomic_t ls_count; + refcount_t ls_count; fl_owner_t ls_owner; }; diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index f90090e..57c38ea 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -2518,7 +2518,7 @@ static int nfs41_check_expired_locks(struct nfs4_state *state) if (test_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags)) { struct rpc_cred *cred = lsp->ls_state->owner->so_cred; - atomic_inc(&lsp->ls_count); + refcount_inc(&lsp->ls_count); spin_unlock(&state->state_lock); nfs4_put_lock_state(prev); @@ -5896,7 +5896,7 @@ static struct nfs4_unlockdata *nfs4_alloc_unlockdata(struct file_lock *fl, p->arg.seqid = seqid; p->res.seqid = seqid; p->lsp = lsp; - atomic_inc(&lsp->ls_count); + refcount_inc(&lsp->ls_count); /* Ensure we don't close file until we're done freeing locks! */ p->ctx = get_nfs_open_context(ctx); p->l_ctx = nfs_get_lock_context(ctx); @@ -6112,7 +6112,7 @@ static struct nfs4_lockdata *nfs4_alloc_lockdata(struct file_lock *fl, p->res.lock_seqid = p->arg.lock_seqid; p->lsp = lsp; p->server = server; - atomic_inc(&lsp->ls_count); + refcount_inc(&lsp->ls_count); p->ctx = get_nfs_open_context(ctx); memcpy(&p->fl, fl, sizeof(p->fl)); return p; diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index 0378e225..1887134 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -825,7 +825,7 @@ __nfs4_find_lock_state(struct nfs4_state *state, ret = pos; } if (ret) - atomic_inc(&ret->ls_count); + refcount_inc(&ret->ls_count); return ret; } @@ -843,7 +843,7 @@ static struct nfs4_lock_state *nfs4_alloc_lock_state(struct nfs4_state *state, f if (lsp == NULL) return NULL; nfs4_init_seqid_counter(&lsp->ls_seqid); - atomic_set(&lsp->ls_count, 1); + refcount_set(&lsp->ls_count, 1); lsp->ls_state = state; lsp->ls_owner = fl_owner; lsp->ls_seqid.owner_id = ida_simple_get(&server->lockowner_id, 0, 0, GFP_NOFS); @@ -907,7 +907,7 @@ void nfs4_put_lock_state(struct nfs4_lock_state *lsp) if (lsp == NULL) return; state = lsp->ls_state; - if (!atomic_dec_and_lock(&lsp->ls_count, &state->state_lock)) + if (!refcount_dec_and_lock(&lsp->ls_count, &state->state_lock)) return; list_del(&lsp->ls_locks); if (list_empty(&state->lock_states)) @@ -927,7 +927,7 @@ static void nfs4_fl_copy_lock(struct file_lock *dst, struct file_lock *src) struct nfs4_lock_state *lsp = src->fl_u.nfs4_fl.owner; dst->fl_u.nfs4_fl.owner = lsp; - atomic_inc(&lsp->ls_count); + refcount_inc(&lsp->ls_count); } static void nfs4_fl_release_lock(struct file_lock *fl)