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 X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 02A81C46461 for ; Mon, 10 May 2021 12:02:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E979261400 for ; Mon, 10 May 2021 12:02:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244276AbhEJL6o (ORCPT ); Mon, 10 May 2021 07:58:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:44332 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235854AbhEJLGW (ORCPT ); Mon, 10 May 2021 07:06:22 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A930D60FE3; Mon, 10 May 2021 10:56:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620644199; bh=6aDdcVRD5XDeRzPu5cDpy+CeTozswdh322xviITHbFE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wpXnFVeeKCC2tns4e0LHH3pFZegfLWpAJQoXjMv6MsqzyKSuCqotc7nkOGXIzEikz SvUI0OGsVftVKxmy7DtIeut0iTDIvFlJ+qtmMTqiIK3WUEBIk3FcZpI94zPOdhx+4w 6QB/7luv9Z7olwx7e5aTr16rHvH5kHH3gR2Y2EEU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arnd Bergmann , Christian Brauner , James Morris , Andrey Zhizhikin Subject: [PATCH 5.11 293/342] security: commoncap: fix -Wstringop-overread warning Date: Mon, 10 May 2021 12:21:23 +0200 Message-Id: <20210510102019.796657790@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210510102010.096403571@linuxfoundation.org> References: <20210510102010.096403571@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Arnd Bergmann commit 82e5d8cc768b0c7b03c551a9ab1f8f3f68d5f83f upstream. gcc-11 introdces a harmless warning for cap_inode_getsecurity: security/commoncap.c: In function ‘cap_inode_getsecurity’: security/commoncap.c:440:33: error: ‘memcpy’ reading 16 bytes from a region of size 0 [-Werror=stringop-overread] 440 | memcpy(&nscap->data, &cap->data, sizeof(__le32) * 2 * VFS_CAP_U32); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The problem here is that tmpbuf is initialized to NULL, so gcc assumes it is not accessible unless it gets set by vfs_getxattr_alloc(). This is a legitimate warning as far as I can tell, but the code is correct since it correctly handles the error when that function fails. Add a separate NULL check to tell gcc about it as well. Signed-off-by: Arnd Bergmann Acked-by: Christian Brauner Signed-off-by: James Morris Cc: Andrey Zhizhikin Signed-off-by: Greg Kroah-Hartman --- security/commoncap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/security/commoncap.c +++ b/security/commoncap.c @@ -391,7 +391,7 @@ int cap_inode_getsecurity(struct inode * &tmpbuf, size, GFP_NOFS); dput(dentry); - if (ret < 0) + if (ret < 0 || !tmpbuf) return ret; fs_ns = inode->i_sb->s_user_ns;