From patchwork Mon Mar 22 16:02:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 12155279 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=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 BB54BC433C1 for ; Mon, 22 Mar 2021 16:05:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 90C38619BA for ; Mon, 22 Mar 2021 16:05:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231693AbhCVQEA (ORCPT ); Mon, 22 Mar 2021 12:04:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:52134 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231759AbhCVQD4 (ORCPT ); Mon, 22 Mar 2021 12:03:56 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4428761998; Mon, 22 Mar 2021 16:03:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1616429036; bh=yFqEt0Vza9xx1ZEH6vpmadF/s9WD+9cr+PvfYFx1jTs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DnY2VvcIHWNR00CmYsS8o9sdpXW8IfqlUTn3pfDogyHxX/SIITlr8SG6GxkT3eSRZ a7K8jLXsPna4Mm190+MpWcuBICb/n+i193Sgx5UJVnr/NQaks4zNGBOOkdJN7kk+Zx IrtL2gHR1/fBjD9NvgLiYwkQqQ/EKWhfodExGrNMHcxDZouSH1dybJZC/EbBnOcXm9 XQLG8dt1bjMaDOofLpAx013Fhy9k111G7DuVnc/32l3avRksgUDzsBf0x12znYeUYk RAdBhG+/y/EhxEsBwjpyhm77vbHfFV6Wbj7ETM5qbIRB/4/X2e34tKnfe8hgDnqlGY gToo1OwJ8lpqg== From: Arnd Bergmann To: linux-kernel@vger.kernel.org, Martin Sebor , Serge Hallyn , James Morris Cc: Arnd Bergmann , x86@kernel.org, Ning Sun , Jani Nikula , Kalle Valo , Simon Kelley , James Smart , "James E.J. Bottomley" , Anders Larsen , Tejun Heo , Imre Deak , linux-arm-kernel@lists.infradead.org, tboot-devel@lists.sourceforge.net, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, ath11k@lists.infradead.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-scsi@vger.kernel.org, cgroups@vger.kernel.org, linux-security-module@vger.kernel.org, "Eric W. Biederman" , Christian Brauner , Kees Cook , Miklos Szeredi , Tycho Andersen Subject: [PATCH 03/11] security: commoncap: fix -Wstringop-overread warning Date: Mon, 22 Mar 2021 17:02:41 +0100 Message-Id: <20210322160253.4032422-4-arnd@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210322160253.4032422-1-arnd@kernel.org> References: <20210322160253.4032422-1-arnd@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: From: Arnd Bergmann 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 --- security/commoncap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/security/commoncap.c b/security/commoncap.c index 28f4d25480df..9a36ed6dd737 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -400,7 +400,7 @@ int cap_inode_getsecurity(struct user_namespace *mnt_userns, &tmpbuf, size, GFP_NOFS); dput(dentry); - if (ret < 0) + if (ret < 0 || !tmpbuf) return ret; fs_ns = inode->i_sb->s_user_ns;