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Tue, 15 Sep 2020 19:44:44 +0000 (GMT) Received: from localhost.localdomain.com (unknown [9.85.140.9]) by b03ledav003.gho.boulder.ibm.com (Postfix) with ESMTP; Tue, 15 Sep 2020 19:44:44 +0000 (GMT) From: Collin Walling To: qemu-devel@nongnu.org, qemu-s390x@nongnu.org Subject: [PATCH v6 3/8] s390/sclp: read sccb from mem based on provided length Date: Tue, 15 Sep 2020 15:44:11 -0400 Message-Id: <20200915194416.107460-4-walling@linux.ibm.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200915194416.107460-1-walling@linux.ibm.com> References: <20200915194416.107460-1-walling@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-09-15_13:2020-09-15, 2020-09-15 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 phishscore=0 clxscore=1015 suspectscore=0 spamscore=0 mlxlogscore=733 malwarescore=0 bulkscore=0 adultscore=0 mlxscore=0 lowpriorityscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009150149 Received-SPF: pass client-ip=148.163.156.1; envelope-from=walling@linux.ibm.com; helo=mx0a-001b2d01.pphosted.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/15 15:14:56 X-ACL-Warn: Detected OS = Linux 3.x [generic] [fuzzy] X-Spam_score_int: -26 X-Spam_score: -2.7 X-Spam_bar: -- X-Spam_report: (-2.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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: thuth@redhat.com, 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" 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 Reviewed-by: Thomas Huth --- hw/s390x/event-facility.c | 2 +- hw/s390x/sclp.c | 55 ++++++++++++++++++++++----------------- include/hw/s390x/sclp.h | 2 +- 3 files changed, 33 insertions(+), 26 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 a37cfbf534..4ae6fb400b 100644 --- a/hw/s390x/sclp.c +++ b/hw/s390x/sclp.c @@ -231,25 +231,29 @@ 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; + g_autofree SCCB *work_sccb = NULL; - 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(be16_to_cpu(header.length)); + s390_cpu_pv_mem_read(env_archcpu(env), 0, work_sccb, + be16_to_cpu(header.length)); if (!sclp_command_code_valid(code)) { - work_sccb.h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND); + work_sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND); goto out_write; } - if (!sccb_verify_boundary(sccb, be16_to_cpu(work_sccb.h.length))) { - work_sccb.h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION); + if (!sccb_verify_boundary(sccb, be16_to_cpu(work_sccb->h.length))) { + work_sccb->h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION); goto out_write; } - sclp_c->execute(sclp, &work_sccb, code); + sclp_c->execute(sclp, work_sccb, code); out_write: - s390_cpu_pv_mem_write(env_archcpu(env), 0, &work_sccb, - be16_to_cpu(work_sccb.h.length)); + s390_cpu_pv_mem_write(env_archcpu(env), 0, work_sccb, + be16_to_cpu(work_sccb->h.length)); sclp_c->service_interrupt(sclp, SCLP_PV_DUMMY_ADDR); return 0; } @@ -258,9 +262,8 @@ int sclp_service_call(CPUS390XState *env, uint64_t sccb, uint32_t code) { SCLPDevice *sclp = get_sclp_device(); SCLPDeviceClass *sclp_c = SCLP_GET_CLASS(sclp); - SCCB work_sccb; - - hwaddr sccb_len = sizeof(SCCB); + SCCBHeader header; + g_autofree SCCB *work_sccb = NULL; /* first some basic checks on program checks */ if (env->psw.mask & PSW_MASK_PSTATE) { @@ -274,32 +277,36 @@ int sclp_service_call(CPUS390XState *env, uint64_t sccb, uint32_t code) return -PGM_SPECIFICATION; } + /* the header contains the actual length of the sccb */ + cpu_physical_memory_read(sccb, &header, sizeof(SCCBHeader)); + + /* Valid sccb sizes */ + if (be16_to_cpu(header.length) < sizeof(SCCBHeader)) { + return -PGM_SPECIFICATION; + } + /* * we want to work on a private copy of the sccb, to prevent guests * from playing dirty tricks by modifying the memory content after * the host has checked the values */ - cpu_physical_memory_read(sccb, &work_sccb, sccb_len); - - /* Valid sccb sizes */ - if (be16_to_cpu(work_sccb.h.length) < sizeof(SCCBHeader)) { - return -PGM_SPECIFICATION; - } + work_sccb = g_malloc0(be16_to_cpu(header.length)); + cpu_physical_memory_read(sccb, work_sccb, be16_to_cpu(header.length)); if (!sclp_command_code_valid(code)) { - work_sccb.h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND); + work_sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND); goto out_write; } - if (!sccb_verify_boundary(sccb, be16_to_cpu(work_sccb.h.length))) { - work_sccb.h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION); + if (!sccb_verify_boundary(sccb, be16_to_cpu(work_sccb->h.length))) { + work_sccb->h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION); goto out_write; } - sclp_c->execute(sclp, &work_sccb, code); + sclp_c->execute(sclp, work_sccb, code); out_write: - cpu_physical_memory_write(sccb, &work_sccb, - be16_to_cpu(work_sccb.h.length)); + cpu_physical_memory_write(sccb, work_sccb, + be16_to_cpu(work_sccb->h.length)); sclp_c->service_interrupt(sclp, sccb); diff --git a/include/hw/s390x/sclp.h b/include/hw/s390x/sclp.h index a87ed2a0ab..98c4727984 100644 --- a/include/hw/s390x/sclp.h +++ b/include/hw/s390x/sclp.h @@ -177,7 +177,7 @@ typedef struct IoaCfgSccb { typedef struct SCCB { SCCBHeader h; - char data[SCCB_DATA_LEN]; + char data[]; } QEMU_PACKED SCCB; #define TYPE_SCLP "sclp"