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Fri, 15 May 2020 22:21:00 +0000 (GMT) Received: from b01ledav004.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1B0F1112066; Fri, 15 May 2020 22:21:00 +0000 (GMT) Received: from localhost.localdomain.com (unknown [9.85.146.125]) by b01ledav004.gho.pok.ibm.com (Postfix) with ESMTP; Fri, 15 May 2020 22:21:00 +0000 (GMT) From: Collin Walling To: qemu-devel@nongnu.org, qemu-s390x@nongnu.org Subject: [PATCH v2 3/8] s390/sclp: rework sclp boundary and length checks Date: Fri, 15 May 2020 18:20:27 -0400 Message-Id: <20200515222032.18838-4-walling@linux.ibm.com> X-Mailer: git-send-email 2.21.3 In-Reply-To: <20200515222032.18838-1-walling@linux.ibm.com> References: <20200515222032.18838-1-walling@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216, 18.0.676 definitions=2020-05-15_07:2020-05-15, 2020-05-15 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 spamscore=0 mlxscore=0 bulkscore=0 priorityscore=1501 mlxlogscore=999 impostorscore=0 adultscore=0 clxscore=1015 cotscore=-2147483648 lowpriorityscore=0 suspectscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2005150181 Received-SPF: pass client-ip=148.163.158.5; envelope-from=walling@linux.ibm.com; helo=mx0a-001b2d01.pphosted.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/15 18:21:01 X-ACL-Warn: Detected OS = Linux 3.x [generic] X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, KHOP_DYNAMIC=0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN 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, svens@linux.ibm.com, pbonzini@redhat.com, mihajlov@linux.ibm.com, rth@twiddle.net Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Rework the SCLP boundary check to account for different SCLP commands (eventually) allowing different boundary sizes. Move the length check code into a separate function, and introduce a new function to determine the length of the read SCP data (i.e. the size from the start of the struct to where the CPU entries should begin). Signed-off-by: Collin Walling --- hw/s390x/sclp.c | 57 ++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 49 insertions(+), 8 deletions(-) diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c index 2bd618515e..987699e3c4 100644 --- a/hw/s390x/sclp.c +++ b/hw/s390x/sclp.c @@ -49,6 +49,34 @@ static inline bool sclp_command_code_valid(uint32_t code) return false; } +static bool sccb_has_valid_boundary(uint64_t sccb_addr, uint32_t code, + SCCBHeader *header) +{ + uint64_t current_len = sccb_addr + be16_to_cpu(header->length); + uint64_t allowed_len = (sccb_addr & PAGE_MASK) + PAGE_SIZE; + + switch (code & SCLP_CMD_CODE_MASK) { + default: + if (current_len <= allowed_len) { + return true; + } + } + header->response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION); + return false; +} + +/* Calculates sufficient SCCB length to store a full Read SCP/CPU response */ +static bool sccb_has_sufficient_len(SCCB *sccb, int num_cpus, int data_len) +{ + int required_len = data_len + num_cpus * sizeof(CPUEntry); + + if (be16_to_cpu(sccb->h.length) < required_len) { + sccb->h.response_code = cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH); + return false; + } + return true; +} + static void prepare_cpu_entries(MachineState *ms, CPUEntry *entry, int *count) { uint8_t features[SCCB_CPU_FEATURE_LEN] = { 0 }; @@ -66,6 +94,16 @@ static void prepare_cpu_entries(MachineState *ms, CPUEntry *entry, int *count) } } +/* + * The data length denotes the start of the struct to where the first + * CPU entry is to be allocated. This value also denotes the offset_cpu + * field. + */ +static int get_read_scp_info_data_len(void) +{ + return offsetof(ReadInfo, entries); +} + /* Provide information about the configuration, CPUs and storage */ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb) { @@ -74,16 +112,16 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb) int cpu_count; int rnsize, rnmax; IplParameterBlock *ipib = s390_ipl_get_iplb(); + int data_len = get_read_scp_info_data_len(); - if (be16_to_cpu(sccb->h.length) < (sizeof(ReadInfo) + cpu_count * sizeof(CPUEntry))) { - sccb->h.response_code = cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH); + if (!sccb_has_sufficient_len(sccb, machine->possible_cpus->len, data_len)) { return; } /* CPU information */ prepare_cpu_entries(machine, read_info->entries, &cpu_count); read_info->entries_cpu = cpu_to_be16(cpu_count); - read_info->offset_cpu = cpu_to_be16(offsetof(ReadInfo, entries)); + read_info->offset_cpu = cpu_to_be16(data_len); read_info->highest_cpu = cpu_to_be16(machine->smp.max_cpus - 1); read_info->ibc_val = cpu_to_be32(s390_get_ibc_val()); @@ -132,16 +170,16 @@ static void sclp_read_cpu_info(SCLPDevice *sclp, SCCB *sccb) { MachineState *machine = MACHINE(qdev_get_machine()); ReadCpuInfo *cpu_info = (ReadCpuInfo *) sccb; + int data_len = offsetof(ReadCpuInfo, entries); int cpu_count; - if (be16_to_cpu(sccb->h.length) < (sizeof(ReadCpuInfo) + cpu_count * sizeof(CPUEntry))) { - sccb->h.response_code = cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH); + if (!sccb_has_sufficient_len(sccb, machine->possible_cpus->len, data_len)) { return; } prepare_cpu_entries(machine, cpu_info->entries, &cpu_count); cpu_info->nr_configured = cpu_to_be16(cpu_count); - cpu_info->offset_configured = cpu_to_be16(offsetof(ReadCpuInfo, entries)); + cpu_info->offset_configured = cpu_to_be16(data_len); cpu_info->nr_standby = cpu_to_be16(0); /* The standby offset is 16-byte for each CPU */ @@ -227,6 +265,10 @@ int sclp_service_call_protected(CPUS390XState *env, uint64_t sccb, goto out_write; } + if (!sccb_has_valid_boundary(sccb, code, &work_sccb.h)) { + goto out_write; + } + sclp_c->execute(sclp, &work_sccb, code); out_write: s390_cpu_pv_mem_write(env_archcpu(env), 0, &work_sccb, @@ -272,8 +314,7 @@ int sclp_service_call(CPUS390XState *env, uint64_t sccb, uint32_t code) goto out_write; } - if ((sccb + be16_to_cpu(work_sccb.h.length)) > ((sccb & PAGE_MASK) + PAGE_SIZE)) { - work_sccb.h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION); + if (!sccb_has_valid_boundary(sccb, code, &work_sccb.h)) { goto out_write; }