From nobody Fri Oct 24 20:26:20 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2BCDBC00140 for ; Mon, 15 Aug 2022 20:07:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242336AbiHOUH2 (ORCPT ); Mon, 15 Aug 2022 16:07:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37334 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345997AbiHOUFz (ORCPT ); Mon, 15 Aug 2022 16:05:55 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE5E880F73; Mon, 15 Aug 2022 11:54:59 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 5176BB810A0; Mon, 15 Aug 2022 18:54:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5B921C433C1; Mon, 15 Aug 2022 18:54:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660589690; bh=2aMAS6nnDE24Xxc3BAWnHHAWPjrQi/Hpa0MkJi+LjSc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Dno4jnR6SlUp2YUQG245vrG4siDJafxSjea1TMs3LxAUWiPvGraXhuBgEG3S8/LUg jl4KNl1hzHsUZbu4ZaZbNMCoSw0ctjqYRpu685LuIhShL5GyIG9HEQdsY4PM59xHWa QJcQMlLKycjyzvZzG+43vVQrVgNzTr1clRt5vPr4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Kasiak , Jeff Layton , Chuck Lever Subject: [PATCH 5.18 0018/1095] lockd: detect and reject lock arguments that overflow Date: Mon, 15 Aug 2022 19:50:17 +0200 Message-Id: <20220815180430.097981703@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180429.240518113@linuxfoundation.org> References: <20220815180429.240518113@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Jeff Layton commit 6930bcbfb6ceda63e298c6af6d733ecdf6bd4cde upstream. lockd doesn't currently vet the start and length in nlm4 requests like it should, and can end up generating lock requests with arguments that overflow when passed to the filesystem. The NLM4 protocol uses unsigned 64-bit arguments for both start and length, whereas struct file_lock tracks the start and end as loff_t values. By the time we get around to calling nlm4svc_retrieve_args, we've lost the information that would allow us to determine if there was an overflow. Start tracking the actual start and len for NLM4 requests in the nlm_lock. In nlm4svc_retrieve_args, vet these values to ensure they won't cause an overflow, and return NLM4_FBIG if they do. Link: https://bugzilla.linux-nfs.org/show_bug.cgi?id=3D392 Reported-by: Jan Kasiak Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever Cc: # 5.14+ Signed-off-by: Greg Kroah-Hartman --- fs/lockd/svc4proc.c | 8 ++++++++ fs/lockd/xdr4.c | 19 ++----------------- include/linux/lockd/xdr.h | 2 ++ 3 files changed, 12 insertions(+), 17 deletions(-) --- a/fs/lockd/svc4proc.c +++ b/fs/lockd/svc4proc.c @@ -32,6 +32,10 @@ nlm4svc_retrieve_args(struct svc_rqst *r if (!nlmsvc_ops) return nlm_lck_denied_nolocks; =20 + if (lock->lock_start > OFFSET_MAX || + (lock->lock_len && ((lock->lock_len - 1) > (OFFSET_MAX - lock->lock_s= tart)))) + return nlm4_fbig; + /* Obtain host handle */ if (!(host =3D nlmsvc_lookup_host(rqstp, lock->caller, lock->len)) || (argp->monitor && nsm_monitor(host) < 0)) @@ -50,6 +54,10 @@ nlm4svc_retrieve_args(struct svc_rqst *r /* Set up the missing parts of the file_lock structure */ lock->fl.fl_file =3D file->f_file[mode]; lock->fl.fl_pid =3D current->tgid; + lock->fl.fl_start =3D (loff_t)lock->lock_start; + lock->fl.fl_end =3D lock->lock_len ? + (loff_t)(lock->lock_start + lock->lock_len - 1) : + OFFSET_MAX; lock->fl.fl_lmops =3D &nlmsvc_lock_operations; nlmsvc_locks_init_private(&lock->fl, host, (pid_t)lock->svid); if (!lock->fl.fl_owner) { --- a/fs/lockd/xdr4.c +++ b/fs/lockd/xdr4.c @@ -20,13 +20,6 @@ =20 #include "svcxdr.h" =20 -static inline loff_t -s64_to_loff_t(__s64 offset) -{ - return (loff_t)offset; -} - - static inline s64 loff_t_to_s64(loff_t offset) { @@ -70,8 +63,6 @@ static bool svcxdr_decode_lock(struct xdr_stream *xdr, struct nlm_lock *lock) { struct file_lock *fl =3D &lock->fl; - u64 len, start; - s64 end; =20 if (!svcxdr_decode_string(xdr, &lock->caller, &lock->len)) return false; @@ -81,20 +72,14 @@ svcxdr_decode_lock(struct xdr_stream *xd return false; if (xdr_stream_decode_u32(xdr, &lock->svid) < 0) return false; - if (xdr_stream_decode_u64(xdr, &start) < 0) + if (xdr_stream_decode_u64(xdr, &lock->lock_start) < 0) return false; - if (xdr_stream_decode_u64(xdr, &len) < 0) + if (xdr_stream_decode_u64(xdr, &lock->lock_len) < 0) return false; =20 locks_init_lock(fl); fl->fl_flags =3D FL_POSIX; fl->fl_type =3D F_RDLCK; - end =3D start + len - 1; - fl->fl_start =3D s64_to_loff_t(start); - if (len =3D=3D 0 || end < 0) - fl->fl_end =3D OFFSET_MAX; - else - fl->fl_end =3D s64_to_loff_t(end); =20 return true; } --- a/include/linux/lockd/xdr.h +++ b/include/linux/lockd/xdr.h @@ -41,6 +41,8 @@ struct nlm_lock { struct nfs_fh fh; struct xdr_netobj oh; u32 svid; + u64 lock_start; + u64 lock_len; struct file_lock fl; };