From patchwork Mon Sep 13 13:15:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 510409 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85432C433EF for ; Mon, 13 Sep 2021 14:40:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6BBAF60F9B for ; Mon, 13 Sep 2021 14:40:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344549AbhIMOmI (ORCPT ); Mon, 13 Sep 2021 10:42:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:56362 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346987AbhIMOkJ (ORCPT ); Mon, 13 Sep 2021 10:40:09 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B1CF561221; Mon, 13 Sep 2021 13:55:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631541334; bh=/Q+nGGbuRQCEf4nJ+zVUPSAiTbJskpr6+hRJit8n4qc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KGyXJ9WPz488BBr7COphtnlT3egrwnZIxtBpNJOzWmWbbyzTDE837HyhwhlUvL11H eDIy+1yR49N60Ds6TvbDtT28KB3DF8JFVRayyajqqiCI5zoZeyydH0i0Hf0zzCLTBT yyrcBDEjG1YGE28XhCLfv2End5Uwn1AtnRXZqQ/8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Len Baker , "Paulo Alcantara (SUSE)" , Jeff Layton , Steve French , Sasha Levin Subject: [PATCH 5.14 256/334] CIFS: Fix a potencially linear read overflow Date: Mon, 13 Sep 2021 15:15:10 +0200 Message-Id: <20210913131122.066861338@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210913131113.390368911@linuxfoundation.org> References: <20210913131113.390368911@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Len Baker [ Upstream commit f980d055a0f858d73d9467bb0b570721bbfcdfb8 ] strlcpy() reads the entire source buffer first. This read may exceed the destination size limit. This is both inefficient and can lead to linear read overflows if a source string is not NUL-terminated. Also, the strnlen() call does not avoid the read overflow in the strlcpy function when a not NUL-terminated string is passed. So, replace this block by a call to kstrndup() that avoids this type of overflow and does the same. Fixes: 066ce6899484d ("cifs: rename cifs_strlcpy_to_host and make it use new functions") Signed-off-by: Len Baker Reviewed-by: Paulo Alcantara (SUSE) Reviewed-by: Jeff Layton Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/cifs/cifs_unicode.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/fs/cifs/cifs_unicode.c b/fs/cifs/cifs_unicode.c index 9bd03a231032..171ad8b42107 100644 --- a/fs/cifs/cifs_unicode.c +++ b/fs/cifs/cifs_unicode.c @@ -358,14 +358,9 @@ cifs_strndup_from_utf16(const char *src, const int maxlen, if (!dst) return NULL; cifs_from_utf16(dst, (__le16 *) src, len, maxlen, codepage, - NO_MAP_UNI_RSVD); + NO_MAP_UNI_RSVD); } else { - len = strnlen(src, maxlen); - len++; - dst = kmalloc(len, GFP_KERNEL); - if (!dst) - return NULL; - strlcpy(dst, src, len); + dst = kstrndup(src, maxlen, GFP_KERNEL); } return dst;