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=-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, 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 CA815C43460 for ; Thu, 20 May 2021 09:44:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AA8D96197D for ; Thu, 20 May 2021 09:44:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233554AbhETJqR (ORCPT ); Thu, 20 May 2021 05:46:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:46586 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233368AbhETJnU (ORCPT ); Thu, 20 May 2021 05:43:20 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A8CA3613DB; Thu, 20 May 2021 09:32:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621503164; bh=0YX0rW6HF7WO0sItRQa5xMnQVHiE+6wfy89xlMzsHxk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nkaTeeSB6pZb/DuIUK7DNJdMW6H5HPoMiTXywt6vTOWQ+56r2c2hu6Oke1jeqKkFf Vy47U10/d4Xj36griff9ZzgKpRHqRf1XP5NQtH6fexITTe5Qhw4QBtH6t44GVMQL0J WhGvddFg3hkZ2TttYLCeAKx5hPvIQh2BU6CL54jc= 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 4.19 097/425] security: commoncap: fix -Wstringop-overread warning Date: Thu, 20 May 2021 11:17:46 +0200 Message-Id: <20210520092134.642028913@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210520092131.308959589@linuxfoundation.org> References: <20210520092131.308959589@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 @@ -397,7 +397,7 @@ 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;