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Mon, 22 Jun 2020 15:22:32 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 379F152050; Mon, 22 Jun 2020 15:22:32 +0000 (GMT) Received: from oc7455500831.ibm.com (unknown [9.145.75.158]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id A13E052052; Mon, 22 Jun 2020 15:22:31 +0000 (GMT) Subject: Re: [PATCH v3 3/8] s390/sclp: rework sclp boundary and length checks To: Collin Walling , qemu-devel@nongnu.org, qemu-s390x@nongnu.org References: <20200618222258.23287-1-walling@linux.ibm.com> <20200618222258.23287-4-walling@linux.ibm.com> From: Christian Borntraeger Autocrypt: addr=borntraeger@de.ibm.com; prefer-encrypt=mutual; keydata= xsFNBE6cPPgBEAC2VpALY0UJjGmgAmavkL/iAdqul2/F9ONz42K6NrwmT+SI9CylKHIX+fdf J34pLNJDmDVEdeb+brtpwC9JEZOLVE0nb+SR83CsAINJYKG3V1b3Kfs0hydseYKsBYqJTN2j CmUXDYq9J7uOyQQ7TNVoQejmpp5ifR4EzwIFfmYDekxRVZDJygD0wL/EzUr8Je3/j548NLyL 4Uhv6CIPf3TY3/aLVKXdxz/ntbLgMcfZsDoHgDk3lY3r1iwbWwEM2+eYRdSZaR4VD+JRD7p8 0FBadNwWnBce1fmQp3EklodGi5y7TNZ/CKdJ+jRPAAnw7SINhSd7PhJMruDAJaUlbYaIm23A +82g+IGe4z9tRGQ9TAflezVMhT5J3ccu6cpIjjvwDlbxucSmtVi5VtPAMTLmfjYp7VY2Tgr+ T92v7+V96jAfE3Zy2nq52e8RDdUo/F6faxcumdl+aLhhKLXgrozpoe2nL0Nyc2uqFjkjwXXI OBQiaqGeWtxeKJP+O8MIpjyGuHUGzvjNx5S/592TQO3phpT5IFWfMgbu4OreZ9yekDhf7Cvn /fkYsiLDz9W6Clihd/xlpm79+jlhm4E3xBPiQOPCZowmHjx57mXVAypOP2Eu+i2nyQrkapaY IdisDQfWPdNeHNOiPnPS3+GhVlPcqSJAIWnuO7Ofw1ZVOyg/jwARAQABzUNDaHJpc3RpYW4g Qm9ybnRyYWVnZXIgKDJuZCBJQk0gYWRkcmVzcykgPGJvcm50cmFlZ2VyQGxpbnV4LmlibS5j b20+wsF5BBMBAgAjBQJdP/hMAhsDBwsJCAcDAgEGFQgCCQoLBBYCAwECHgECF4AACgkQEXu8 gLWmHHy/pA/+JHjpEnd01A0CCyfVnb5fmcOlQ0LdmoKWLWPvU840q65HycCBFTt6V62cDljB kXFFxMNA4y/2wqU0H5/CiL963y3gWIiJsZa4ent+KrHl5GK1nIgbbesfJyA7JqlB0w/E/SuY NRQwIWOo/uEvOgXnk/7+rtvBzNaPGoGiiV1LZzeaxBVWrqLtmdi1iulW/0X/AlQPuF9dD1Px hx+0mPjZ8ClLpdSp5d0yfpwgHtM1B7KMuQPQZGFKMXXTUd3ceBUGGczsgIMipZWJukqMJiJj QIMH0IN7XYErEnhf0GCxJ3xAn/J7iFpPFv8sFZTvukntJXSUssONnwiKuld6ttUaFhSuSoQg OFYR5v7pOfinM0FcScPKTkrRsB5iUvpdthLq5qgwdQjmyINt3cb+5aSvBX2nNN135oGOtlb5 tf4dh00kUR8XFHRrFxXx4Dbaw4PKgV3QLIHKEENlqnthH5t0tahDygQPnSucuXbVQEcDZaL9 WgJqlRAAj0pG8M6JNU5+2ftTFXoTcoIUbb0KTOibaO9zHVeGegwAvPLLNlKHiHXcgLX1tkjC DrvE2Z0e2/4q7wgZgn1kbvz7ZHQZB76OM2mjkFu7QNHlRJ2VXJA8tMXyTgBX6kq1cYMmd/Hl OhFrAU3QO1SjCsXA2CDk9MM1471mYB3CTXQuKzXckJnxHkHOwU0ETpw8+AEQAJjyNXvMQdJN t07BIPDtbAQk15FfB0hKuyZVs+0lsjPKBZCamAAexNRk11eVGXK/YrqwjChkk60rt3q5i42u PpNMO9aS8cLPOfVft89Y654Qd3Rs1WRFIQq9xLjdLfHh0i0jMq5Ty+aiddSXpZ7oU6E+ud+X Czs3k5RAnOdW6eV3+v10sUjEGiFNZwzN9Udd6PfKET0J70qjnpY3NuWn5Sp1ZEn6lkq2Zm+G 9G3FlBRVClT30OWeiRHCYB6e6j1x1u/rSU4JiNYjPwSJA8EPKnt1s/Eeq37qXXvk+9DYiHdT PcOa3aNCSbIygD3jyjkg6EV9ZLHibE2R/PMMid9FrqhKh/cwcYn9FrT0FE48/2IBW5mfDpAd YvpawQlRz3XJr2rYZJwMUm1y+49+1ZmDclaF3s9dcz2JvuywNq78z/VsUfGz4Sbxy4ShpNpG REojRcz/xOK+FqNuBk+HoWKw6OxgRzfNleDvScVmbY6cQQZfGx/T7xlgZjl5Mu/2z+ofeoxb vWWM1YCJAT91GFvj29Wvm8OAPN/+SJj8LQazd9uGzVMTz6lFjVtH7YkeW/NZrP6znAwv5P1a DdQfiB5F63AX++NlTiyA+GD/ggfRl68LheSskOcxDwgI5TqmaKtX1/8RkrLpnzO3evzkfJb1 D5qh3wM1t7PZ+JWTluSX8W25ABEBAAHCwV8EGAECAAkFAk6cPPgCGwwACgkQEXu8gLWmHHz8 2w//VjRlX+tKF3szc0lQi4X0t+pf88uIsvR/a1GRZpppQbn1jgE44hgF559K6/yYemcvTR7r 6Xt7cjWGS4wfaR0+pkWV+2dbw8Xi4DI07/fN00NoVEpYUUnOnupBgychtVpxkGqsplJZQpng v6fauZtyEcUK3dLJH3TdVQDLbUcL4qZpzHbsuUnTWsmNmG4Vi0NsEt1xyd/Wuw+0kM/oFEH1 4BN6X9xZcG8GYUbVUd8+bmio8ao8m0tzo4pseDZFo4ncDmlFWU6hHnAVfkAs4tqA6/fl7RLN JuWBiOL/mP5B6HDQT9JsnaRdzqF73FnU2+WrZPjinHPLeE74istVgjbowvsgUqtzjPIG5pOj cAsKoR0M1womzJVRfYauWhYiW/KeECklci4TPBDNx7YhahSUlexfoftltJA8swRshNA/M90/ i9zDo9ySSZHwsGxG06ZOH5/MzG6HpLja7g8NTgA0TD5YaFm/oOnsQVsf2DeAGPS2xNirmknD jaqYefx7yQ7FJXXETd2uVURiDeNEFhVZWb5CiBJM5c6qQMhmkS4VyT7/+raaEGgkEKEgHOWf ZDP8BHfXtszHqI3Fo1F4IKFo/AP8GOFFxMRgbvlAs8z/+rEEaQYjxYJqj08raw6P4LFBqozr nS4h0HDFPrrp1C2EMVYIQrMokWvlFZbCpsdYbBI= Message-ID: Date: Mon, 22 Jun 2020 17:22:31 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200618222258.23287-4-walling@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216, 18.0.687 definitions=2020-06-22_08:2020-06-22, 2020-06-22 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 impostorscore=0 suspectscore=0 mlxlogscore=999 cotscore=-2147483648 mlxscore=0 adultscore=0 phishscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 malwarescore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006220114 Received-SPF: pass client-ip=148.163.156.1; envelope-from=borntraeger@de.ibm.com; helo=mx0a-001b2d01.pphosted.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/22 09:01:08 X-ACL-Warn: Detected OS = Linux 3.x [generic] [fuzzy] X-Spam_score_int: -35 X-Spam_score: -3.6 X-Spam_bar: --- X-Spam_report: (-3.6 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=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, mst@redhat.com, svens@linux.ibm.com, pbonzini@redhat.com, mihajlov@linux.ibm.com, rth@twiddle.net Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 19.06.20 00:22, Collin Walling wrote: > 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). > > The format of read CPU info is unlikely to change in the future, > so we do not require a separate function to calculate its length. > > Signed-off-by: Collin Walling > --- > hw/s390x/sclp.c | 59 ++++++++++++++++++++++++++++++++++++++++--------- > 1 file changed, 49 insertions(+), 10 deletions(-) > > diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c > index 181ce04007..0710138f91 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) As you write to the sccb in case of error, mabye sccb_verify_boundary instead of has_valid. has_valid feels like a read-only function. > +{ > + uint64_t sccb_max_addr = sccb_addr + be16_to_cpu(header->length) - 1; > + uint64_t sccb_boundary = (sccb_addr & PAGE_MASK) + PAGE_SIZE; > + > + switch (code & SCLP_CMD_CODE_MASK) { > + default: > + if (sccb_max_addr < sccb_boundary) { > + 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_sufficient_len(SCCB *sccb, int num_cpus, int data_len) same here, maybe sccb_verify_length > +{ > + 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 inline 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) > { > @@ -74,17 +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) + machine->possible_cpus->len * sizeof(CPUEntry))) { > - sccb->h.response_code = cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH); > + if (!sccb_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()); > @@ -133,17 +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(ReadInfo) + machine->possible_cpus->len * sizeof(CPUEntry))) { > - sccb->h.response_code = cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH); > + if (!sccb_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 */ > @@ -229,6 +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, > @@ -274,8 +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; > } > >