On 9/12/20 2:28 AM, Thomas Huth wrote: > 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 <wall...@linux.ibm.com> >>>>> --- >>>>> 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 > >
Err, yes you're right. -- Regards, Collin Stay safe and stay healthy