Re: [PATCH-for-6.0?] mptsas: remove unused MPTSASState.pending (CVE-2021-3392)

[Philippe Mathieu-Daudé]

Cc'ing maintainers.

On 4/16/21 1:27 PM, Philippe Mathieu-Daudé wrote:
> On 4/16/21 12:22 PM, Michael Tokarev wrote:
>> During previous attempt to fix CVE-2021-3392 it was discovered
>> that MPTSASState.pending is actually not used. So instead of
>> fixing the prob, just remove the offending code entirely
> 
> What problem?
> 
>>
>> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
>> Cc: Prasad J Pandit <pjp@fedoraproject.org>
>> Cc: qemu-stable@nongnu.org
>> ---
>>  hw/scsi/mptsas.c | 4 ----
>>  hw/scsi/mptsas.h | 1 -
>>  2 files changed, 5 deletions(-)
>>
>> diff --git a/hw/scsi/mptsas.c b/hw/scsi/mptsas.c
>> index 7416e78706..5abbc742aa 100644
>> --- a/hw/scsi/mptsas.c
>> +++ b/hw/scsi/mptsas.c
>> @@ -257,7 +257,6 @@ static void mptsas_free_request(MPTSASRequest *req)
>>          req->sreq->hba_private = NULL;
>>          scsi_req_unref(req->sreq);
>>          req->sreq = NULL;
>> -        QTAILQ_REMOVE(&s->pending, req, next);
>>      }
>>      qemu_sglist_destroy(&req->qsg);
>>      g_free(req);
>> @@ -303,7 +302,6 @@ static int mptsas_process_scsi_io_request(MPTSASState *s,
>>      }
>>  
>>      req = g_new0(MPTSASRequest, 1);
>> -    QTAILQ_INSERT_TAIL(&s->pending, req, next);
>>      req->scsi_io = *scsi_io;
>>      req->dev = s;
>>  
>> @@ -1319,8 +1317,6 @@ static void mptsas_scsi_realize(PCIDevice *dev, Error 
>> **errp)
>>  
>>      s->request_bh = qemu_bh_new(mptsas_fetch_requests, s);
>>  
>> -    QTAILQ_INIT(&s->pending);
>> -
>>      scsi_bus_new(&s->bus, sizeof(s->bus), &dev->qdev, &mptsas_scsi_info, 
>> NULL);
>>  }
>>  
>> diff --git a/hw/scsi/mptsas.h b/hw/scsi/mptsas.h
>> index b85ac1a5fc..c046497db7 100644
>> --- a/hw/scsi/mptsas.h
>> +++ b/hw/scsi/mptsas.h
>> @@ -79,7 +79,6 @@ struct MPTSASState {
>>      uint16_t reply_frame_size;
>>  
>>      SCSIBus bus;
>> -    QTAILQ_HEAD(, MPTSASRequest) pending;
>>  };
>>  
>>  void mptsas_fix_scsi_io_endianness(MPIMsgSCSIIORequest *req);
>>
>