From mboxrd@z Thu Jan 1 00:00:00 1970 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 A03A0C46467 for ; Mon, 16 Jan 2023 16:29:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233206AbjAPQ3F (ORCPT ); Mon, 16 Jan 2023 11:29:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232949AbjAPQ20 (ORCPT ); Mon, 16 Jan 2023 11:28:26 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9863D2CC6D for ; Mon, 16 Jan 2023 08:16:48 -0800 (PST) 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 3E070B81063 for ; Mon, 16 Jan 2023 16:16:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 989CAC433D2; Mon, 16 Jan 2023 16:16:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673885806; bh=hK5M+8mDAeoDSkF9V8hkWds66sA8FAHmoPCuTTJlqJs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TUxOJPTi/65Ei/glvyyP8sKAR7IZHEnF6NLB9ydkuMTYo6GRPXxG8o32Z8L8isFLC rkVcrFwwq8F8ML8QucTnLH6PN26gObLSgcUzAqlfpKX6mA9eYbnK1oFMAHnRsgUkru w+wmviGGOFhve3xBjc6WfaVsvfdJjUcAy53LmHc4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Trond Myklebust , Sasha Levin Subject: [PATCH 5.4 161/658] NFSv4.2: Fix a memory stomp in decode_attr_security_label Date: Mon, 16 Jan 2023 16:44:09 +0100 Message-Id: <20230116154916.823710172@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154909.645460653@linuxfoundation.org> References: <20230116154909.645460653@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Trond Myklebust [ Upstream commit 43c1031f7110967c240cb6e922adcfc4b8899183 ] We must not change the value of label->len if it is zero, since that indicates we stored a label. Fixes: b4487b935452 ("nfs: Fix getxattr kernel panic and memory overflow") Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin --- fs/nfs/nfs4xdr.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c index ac9ffe184451..a3592becae4a 100644 --- a/fs/nfs/nfs4xdr.c +++ b/fs/nfs/nfs4xdr.c @@ -4171,12 +4171,10 @@ static int decode_attr_security_label(struct xdr_stream *xdr, uint32_t *bitmap, return -EIO; bitmap[2] &= ~FATTR4_WORD2_SECURITY_LABEL; if (len < NFS4_MAXLABELLEN) { - if (label) { - if (label->len) { - if (label->len < len) - return -ERANGE; - memcpy(label->label, p, len); - } + if (label && label->len) { + if (label->len < len) + return -ERANGE; + memcpy(label->label, p, len); label->len = len; label->pi = pi; label->lfs = lfs; -- 2.35.1