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bh=QVdtENz48/YR2yY0tFtha0Dp8M1kEziomsL89XYH/oY=; b=dbOESNxwKUYE6pBsavuI/zVH8bnrTM0cJoKD6bRXwlvuMl9lXQFhkyq5olI2muqmdv2Zqq KdUgKXKO6VgXgRrSP1CXp05C7lhK/Axuim8/jsl8dYfPpHZ5yNJvp19SpiToKaC8+3bJrc Hxnu3sOxaRr9rhhriSgOqY9mdjMiFec= 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-124-tmHYC558PbmpowmaOzGZ4w-1; Sat, 12 Sep 2020 02:28:50 -0400 X-MC-Unique: tmHYC558PbmpowmaOzGZ4w-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 9BF8081F006; Sat, 12 Sep 2020 06:28:48 +0000 (UTC) Received: from thuth.remote.csb (ovpn-112-6.ams2.redhat.com [10.36.112.6]) by smtp.corp.redhat.com (Postfix) with ESMTP id AF79E60BEC; Sat, 12 Sep 2020 06:28:39 +0000 (UTC) Subject: Re: [PATCH v5 3/8] s390/sclp: read sccb from mem based on provided length To: Collin Walling , qemu-devel@nongnu.org, qemu-s390x@nongnu.org References: <20200910093655.255774-1-walling@linux.ibm.com> <20200910093655.255774-4-walling@linux.ibm.com> <02dabe89-8df2-90d4-c7f1-5ef951942639@redhat.com> <811e906a-689e-a53c-706e-5d6217ef3cb2@linux.ibm.com> <2b7a8807-279f-1256-e89b-0f53ae6d5623@linux.ibm.com> From: Thomas Huth Message-ID: Date: Sat, 12 Sep 2020 08:28:38 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <2b7a8807-279f-1256-e89b-0f53ae6d5623@linux.ibm.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: 0.003 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Received-SPF: pass client-ip=63.128.21.124; envelope-from=thuth@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/12 02:04:36 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -45 X-Spam_score: -4.6 X-Spam_bar: ---- X-Spam_report: (-4.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-2.469, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=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: frankja@linux.ibm.com, david@redhat.com, cohuck@redhat.com, pasic@linux.ibm.com, borntraeger@de.ibm.com, mst@redhat.com, pbonzini@redhat.com, sumanthk@linux.ibm.com, mihajlov@linux.ibm.com, rth@twiddle.net Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 11/09/2020 20.16, Collin Walling wrote: > On 9/10/20 1:56 PM, Collin Walling wrote: >> On 9/10/20 1:50 PM, Thomas Huth wrote: >>> On 10/09/2020 11.36, Collin Walling wrote: >>>> The header contained within the SCCB passed to the SCLP service call >>>> contains the actual length of the SCCB. Instead of allocating a static >>>> 4K size for the work sccb, let's allow for a variable size determined >>>> by the value in the header. The proper checks are already in place to >>>> ensure the SCCB length is sufficent to store a full response and that >>>> the length does not cross any explicitly-set boundaries. >>>> >>>> Signed-off-by: Collin Walling >>>> --- >>>> hw/s390x/event-facility.c | 2 +- >>>> hw/s390x/sclp.c | 58 ++++++++++++++++++++++----------------- >>>> include/hw/s390x/sclp.h | 2 +- >>>> 3 files changed, 35 insertions(+), 27 deletions(-) >>>> >>>> diff --git a/hw/s390x/event-facility.c b/hw/s390x/event-facility.c >>>> index 645b4080c5..ed92ce510d 100644 >>>> --- a/hw/s390x/event-facility.c >>>> +++ b/hw/s390x/event-facility.c >>>> @@ -213,7 +213,7 @@ static uint16_t handle_sccb_read_events(SCLPEventFacility *ef, SCCB *sccb, >>>> >>>> event_buf = &red->ebh; >>>> event_buf->length = 0; >>>> - slen = sizeof(sccb->data); >>>> + slen = sccb_data_len(sccb); >>>> >>>> rc = SCLP_RC_NO_EVENT_BUFFERS_STORED; >>>> >>>> diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c >>>> index 69a8724dc7..cb8e2e8ec3 100644 >>>> --- a/hw/s390x/sclp.c >>>> +++ b/hw/s390x/sclp.c >>>> @@ -231,25 +231,30 @@ int sclp_service_call_protected(CPUS390XState *env, uint64_t sccb, >>>> { >>>> SCLPDevice *sclp = get_sclp_device(); >>>> SCLPDeviceClass *sclp_c = SCLP_GET_CLASS(sclp); >>>> - SCCB work_sccb; >>>> - hwaddr sccb_len = sizeof(SCCB); >>>> + SCCBHeader header; >>>> + SCCB *work_sccb; >>> >>> I'd maybe use "g_autofree SCCB *work_sccb = NULL" so you don't have to >>> worry about doing the g_free() later. >> >> Can do. >> >>> >>>> - s390_cpu_pv_mem_read(env_archcpu(env), 0, &work_sccb, sccb_len); >>>> + s390_cpu_pv_mem_read(env_archcpu(env), 0, &header, sizeof(SCCBHeader)); >>>> + >>>> + work_sccb = g_malloc0(header.length); >>> >>> Please use be16_to_cpu(header.length) here as well. >> >> Good catch, thanks! >> > > Shouldn't the mallocs use cpu_to_be16 instead since the header length > was read in from a cpu? Now you confuse me ... s390x is big endian, so to get a usable value, we have to convert big-endian to the host byte order, not the other way round, don't we? Thomas