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Re: [PATCH v3 2/8] s390/sclp: check sccb len before filling in data
From: |
David Hildenbrand |
Subject: |
Re: [PATCH v3 2/8] s390/sclp: check sccb len before filling in data |
Date: |
Fri, 19 Jun 2020 16:45:11 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 |
On 19.06.20 00:22, Collin Walling wrote:
> The SCCB must be checked for a sufficient length before it is filled
> with any data. If the length is insufficient, then the SCLP command
> is suppressed and the proper response code is set in the SCCB header.
>
> Fixes: 832be0d8a3bb ("s390x: sclp: Report insufficient SCCB length")
> Signed-off-by: Collin Walling <walling@linux.ibm.com>
> Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
> ---
> hw/s390x/sclp.c | 24 ++++++++++++------------
> 1 file changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
> index 7875334037..181ce04007 100644
> --- a/hw/s390x/sclp.c
> +++ b/hw/s390x/sclp.c
> @@ -75,6 +75,12 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb)
> int rnsize, rnmax;
> IplParameterBlock *ipib = s390_ipl_get_iplb();
>
> + 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);
> + return;
> + }
> +
> /* CPU information */
> prepare_cpu_entries(machine, read_info->entries, &cpu_count);
> read_info->entries_cpu = cpu_to_be16(cpu_count);
> @@ -83,12 +89,6 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb)
>
> read_info->ibc_val = cpu_to_be32(s390_get_ibc_val());
>
> - 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);
> - return;
> - }
> -
> /* Configuration Characteristic (Extension) */
> s390_get_feat_block(S390_FEAT_TYPE_SCLP_CONF_CHAR,
> read_info->conf_char);
> @@ -135,17 +135,17 @@ static void sclp_read_cpu_info(SCLPDevice *sclp, SCCB
> *sccb)
> ReadCpuInfo *cpu_info = (ReadCpuInfo *) sccb;
> int cpu_count;
>
> - 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->nr_standby = cpu_to_be16(0);
> -
> if (be16_to_cpu(sccb->h.length) <
> - (sizeof(ReadCpuInfo) + cpu_count * sizeof(CPUEntry))) {
> + (sizeof(ReadInfo) + machine->possible_cpus->len *
> sizeof(CPUEntry))) {
> sccb->h.response_code =
> cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH);
> 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->nr_standby = cpu_to_be16(0);
> +
> /* The standby offset is 16-byte for each CPU */
> cpu_info->offset_standby = cpu_to_be16(cpu_info->offset_configured
> + cpu_info->nr_configured*sizeof(CPUEntry));
>
Reviewed-by: David Hildenbrand <david@redhat.com>
--
Thanks,
David / dhildenb