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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4BD01E77188 for ; Wed, 8 Jan 2025 11:48:18 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tVUXD-0005B6-IN; Wed, 08 Jan 2025 06:47:40 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tVUX9-00059k-AP for qemu-devel@nongnu.org; Wed, 08 Jan 2025 06:47:36 -0500 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tVUX6-0007sD-Nm for qemu-devel@nongnu.org; Wed, 08 Jan 2025 06:47:35 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=MIME-Version:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=wzXIdpiWQGQTkGQ2afOnCj0XuwK/kMz/KmUfObdPHis=; b=eeQNHjQlcOpnXecnRenKFEr6Ya HYFtCZsJvmswb+bWDRtw1xbY2g8N2UgqRF/E1JEupCmO+5Y9bNcGpaN3J9UDlIw0klY1Tig8IpIkb 8PVkULsDE7n31Xrzl6C8JxZmoCX9vgwRpQUGVCOYzpChnFpvzNk/bd8K3zMlhssD4Kaqr3R9nrowp 3JezZC4ERwUbPcIh7vKaRL5EXdnPBFHLNSdWidKgQUIsS5na73Ref3Elzvg2ddyDcqouEWsQYkIMm TBRILQt+P8FbmO/AsWECSXhpiX0Rh6qZ1805aCgfl+YmRFL+jMeq0JaAVWqZQ8nshiuhJ5kHrz90d 3ZDaNgXQ==; Received: from 54-240-197-238.amazon.com ([54.240.197.238] helo=u09cd745991455d.ant.amazon.com) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tVUX0-0000000GKf0-1B3h; Wed, 08 Jan 2025 11:47:26 +0000 Message-ID: <6a067b445df6e5797e001665ab8554e4fc5085fe.camel@infradead.org> Subject: Re: [PATCH] hw/xen: Check if len is 0 before memcpy() From: David Woodhouse To: Akihiko Odaki , Paul Durrant , "Michael S. Tsirkin" , Marcel Apfelbaum , Paolo Bonzini , Richard Henderson , Eduardo Habkost Cc: qemu-devel@nongnu.org, devel@daynix.com Date: Wed, 08 Jan 2025 11:47:25 +0000 In-Reply-To: <20250108-xen-v1-1-3f95cd358eed@daynix.com> References: <20250108-xen-v1-1-3f95cd358eed@daynix.com> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/pkcs7-signature"; boundary="=-9iv5Ah0pFwtfFBGQXNpr" User-Agent: Evolution 3.52.3-0ubuntu1 MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Received-SPF: none client-ip=2001:8b0:10b:1236::1; envelope-from=BATV+b94846bdbc75b454f255+7808+infradead.org+dwmw2@casper.srs.infradead.org; helo=casper.infradead.org X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --=-9iv5Ah0pFwtfFBGQXNpr Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2025-01-08 at 20:31 +0900, Akihiko Odaki wrote: > data->data can be NULL when len is 0. Strictly speaking, the behavior > of memcpy() in such a scenario is undefined so UBSan complaints. >=20 > Satisfy UBSan by checking if len is 0 before memcpy(). >=20 > Signed-off-by: Akihiko Odaki Reviewed-by: David Woodhouse Thanks. > --- > =C2=A0hw/i386/kvm/xen_xenstore.c | 4 ++++ > =C2=A01 file changed, 4 insertions(+) >=20 > diff --git a/hw/i386/kvm/xen_xenstore.c b/hw/i386/kvm/xen_xenstore.c > index 59691056670e..17802aa33d20 100644 > --- a/hw/i386/kvm/xen_xenstore.c > +++ b/hw/i386/kvm/xen_xenstore.c > @@ -532,6 +532,10 @@ static void xs_read(XenXenstoreState *s, > unsigned int req_id, > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 return; > =C2=A0=C2=A0=C2=A0=C2=A0 } > =C2=A0 > +=C2=A0=C2=A0=C2=A0 if (!len) { > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 return; > +=C2=A0=C2=A0=C2=A0 } > + > =C2=A0=C2=A0=C2=A0=C2=A0 memcpy(&rsp_data[rsp->len], data->data, len); > =C2=A0=C2=A0=C2=A0=C2=A0 rsp->len +=3D len; > =C2=A0} >=20 > --- > base-commit: 38d0939b86e2eef6f6a622c6f1f7befda0146595 > change-id: 20241227-xen-fb5a15cc0ca7 >=20 > Best regards, --=-9iv5Ah0pFwtfFBGQXNpr Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCD9Aw ggSOMIIDdqADAgECAhAOmiw0ECVD4cWj5DqVrT9PMA0GCSqGSIb3DQEBCwUAMGUxCzAJBgNVBAYT AlVTMRUwEwYDVQQKEwxEaWdpQ2VydCBJbmMxGTAXBgNVBAsTEHd3dy5kaWdpY2VydC5jb20xJDAi BgNVBAMTG0RpZ2lDZXJ0IEFzc3VyZWQgSUQgUm9vdCBDQTAeFw0yNDAxMzAwMDAwMDBaFw0zMTEx MDkyMzU5NTlaMEExCzAJBgNVBAYTAkFVMRAwDgYDVQQKEwdWZXJva2V5MSAwHgYDVQQDExdWZXJv a2V5IFNlY3VyZSBFbWFpbCBHMjCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAMjvgLKj jfhCFqxYyRiW8g3cNFAvltDbK5AzcOaR7yVzVGadr4YcCVxjKrEJOgi7WEOH8rUgCNB5cTD8N/Et GfZI+LGqSv0YtNa54T9D1AWJy08ZKkWvfGGIXN9UFAPMJ6OLLH/UUEgFa+7KlrEvMUupDFGnnR06 aDJAwtycb8yXtILj+TvfhLFhafxroXrflspavejQkEiHjNjtHnwbZ+o43g0/yxjwnarGI3kgcak7 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