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dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:42154 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kywjH-0006r1-Ay for qemu-devel@archiver.kernel.org; Mon, 11 Jan 2021 07:55:27 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:39200) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kywi7-0005r9-Gg for qemu-devel@nongnu.org; Mon, 11 Jan 2021 07:54:15 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:29568) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kywi5-00017e-UU for qemu-devel@nongnu.org; Mon, 11 Jan 2021 07:54:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610369653; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=h2DtVLnAxjClwiQSM4SMei+Ah+38pm7TKMeQdm4Z37w=; b=T1V+wMfdpgxIdA/bhaGBAXrYLuIk82tHkG+l73qjrDkfWZxV/KtLz3AG1y8eQkre4qrfyd lSE/B0ul4HNw6wINzjm924EJIx6vlJeI8hd6MiX8BKGtH+tH2sd6XL0DctpvwB/aW/Ygy3 OBWfqO4pQkJehvcEddNYIvnWzaJmyMk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-111-h9ftMEOqMziLdwV7dU_sTw-1; Mon, 11 Jan 2021 07:54:09 -0500 X-MC-Unique: h9ftMEOqMziLdwV7dU_sTw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B518F800050; Mon, 11 Jan 2021 12:54:08 +0000 (UTC) Received: from thuth.remote.csb (ovpn-112-147.ams2.redhat.com [10.36.112.147]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5A36B60C62; Mon, 11 Jan 2021 12:54:07 +0000 (UTC) Subject: Re: [RHEL7 qemu-kvm PATCH 2/3] s390x: Fix vm name copy length To: Miroslav Rezanina References: <5acb5521-fdd2-e511-9cc3-176086183dd5@redhat.com> <88c2eb01-f8f5-18d5-6513-57322930cc77@redhat.com> <115622555.32388560.1610368920610.JavaMail.zimbra@redhat.com> From: Thomas Huth Message-ID: Date: Mon, 11 Jan 2021 13:54:06 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <115622555.32388560.1610368920610.JavaMail.zimbra@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=thuth@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=thuth@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.251, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-s390x , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 11/01/2021 13.42, Miroslav Rezanina wrote: > > > ----- Original Message ----- >> From: "Thomas Huth" >> To: "Philippe Mathieu-Daudé" , mrezanin@redhat.com, qemu-devel@nongnu.org, "qemu-s390x" >> >> Sent: Monday, January 11, 2021 1:24:57 PM >> Subject: Re: [RHEL7 qemu-kvm PATCH 2/3] s390x: Fix vm name copy length >> >> On 11/01/2021 13.10, Philippe Mathieu-Daudé wrote: >>> Hi Miroslav, >>> >>> On 1/11/21 12:30 PM, mrezanin@redhat.com wrote: >>>> From: Miroslav Rezanina >>>> >>>> There are two cases when vm name is copied but closing \0 can be lost >>>> in case name is too long (>=256 characters). >>>> >>>> Updating length to copy so there is space for closing \0. >>>> >>>> Signed-off-by: Miroslav Rezanina >>>> --- >>>> target/s390x/kvm.c | 2 +- >>>> target/s390x/misc_helper.c | 4 +++- >>>> 2 files changed, 4 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c >>>> index b8385e6b95..2313b5727e 100644 >>>> --- a/target/s390x/kvm.c >>>> +++ b/target/s390x/kvm.c >>>> @@ -1918,7 +1918,7 @@ static void insert_stsi_3_2_2(S390CPU *cpu, __u64 >>>> addr, uint8_t ar) >>>> */ >>>> if (qemu_name) { >>>> strncpy((char *)sysib.ext_names[0], qemu_name, >>>> - sizeof(sysib.ext_names[0])); >>>> + sizeof(sysib.ext_names[0]) - 1); >>>> } else { >>>> strcpy((char *)sysib.ext_names[0], "KVMguest"); >>>> } >>> >>> What about using strpadcpy() instead? >> >> Yes, strpadcpy is the better way here - this field has to be padded with >> zeroes, so doing "- 1" is wrong here. > > Hi Thomas, > > as I wrote in reply to Phillipe - the array is memset to zeroes before the if so we > are sure it's padded with zeroes (in this occurrence, not true for second one). Ok, but dropping the last character is still wrong here. The ext_names do not need to be terminated with a \0 if they have the full length. Thomas