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: 12155269 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=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 2F656C433C1 for ; Mon, 22 Mar 2021 16:06:57 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C8D2D619B5 for ; Mon, 22 Mar 2021 16:06:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C8D2D619B5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0LMQHcpZczPMOAhm6f9TZOO3RolB2buUmT8xHomVhLI=; b=qcqfaC8x1f2/3/BqaxQVKwcse foIoDuYwY+uDRehH+DinvgeWf9Bi+1/XKBShfr9BKujU+c79DWRm6q0xGxT+aSl2sLddar7QTEy5t IRKEr9pg1U2cJnWhPhYIsSOYMwIZSrtTrW5nuC34XX9gJH+VmVTlroPzaUJwqn/yzkDfa3W8NXwfB LKGmsVc6P/UqZbELq+sdFDCDf+ICiGUAhw/Skx5qU6xCNpIjf1T00Tr9KIPTc7SKLtVBqVivW7hSF rYcASGKvCiU5tsy73WT8P5P4jZuqbkfkrM7/XMMDrC12YRDWowt1mQw2PUxlv5J4mXR21V+YpTXmf rQwY47JPA==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lON2I-00BxKn-SV; Mon, 22 Mar 2021 16:04:11 +0000 Received: from mail.kernel.org ([198.145.29.99]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lON25-00BxHu-Rk; Mon, 22 Mar 2021 16:04:03 +0000 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210322_160401_660157_F038AFE2 X-CRM114-Status: GOOD ( 14.21 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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;