diff mbox

scsi: sr: fix oob access in get_capabilities

Message ID yq160j7lbx1.fsf@oracle.com (mailing list archive)
State Accepted, archived
Headers show

Commit Message

Martin K. Petersen March 17, 2017, 11:29 p.m. UTC 
Kefeng Wang <wangkefeng.wang@huawei.com> writes:

Kefeng,

> root@localhost ~]# sg_modes -p 0x2a /dev/sr0
>     QEMU      QEMU DVD-ROM      0.15   peripheral_type: cd/dvd [0x5]
> Mode parameter header from MODE SENSE(10):
> Invalid block descriptor length=512, ignore
>   Mode data length=36, medium type=0x70, specific param=0x00, longlba=0
>   Block descriptor length=0
>>> MM capabilities and mechanical status (obsolete), page_control: current
>  00     2a 12 00 00 71 60 29 00  02 c2 00 02 02 00 02 c2
>  10     00 00 00 00
> Unexpectedly received extra mode page responses, ignore

That looks pretty broken.

Could you try the following patch?

Thanks!

Comments

Kefeng Wang March 20, 2017, 6 a.m. UTC | #1 
On 2017/3/18 7:29, Martin K. Petersen wrote:
> Kefeng Wang <wangkefeng.wang@huawei.com> writes:
> 
> Kefeng,
> 
>> root@localhost ~]# sg_modes -p 0x2a /dev/sr0
>>     QEMU      QEMU DVD-ROM      0.15   peripheral_type: cd/dvd [0x5]
>> Mode parameter header from MODE SENSE(10):
>> Invalid block descriptor length=512, ignore
>>   Mode data length=36, medium type=0x70, specific param=0x00, longlba=0
>>   Block descriptor length=0
>>>> MM capabilities and mechanical status (obsolete), page_control: current
>>  00     2a 12 00 00 71 60 29 00  02 c2 00 02 02 00 02 c2
>>  10     00 00 00 00
>> Unexpectedly received extra mode page responses, ignore
> 
> That looks pretty broken.
> 
> Could you try the following patch?

The issue still exists, the patch return zero in scsi_mode_sense(), but zero means
SAM_STAT_GOOD in scsi_status_is_good(), so n will be still bigger than 512;

Thanks,
diff mbox

Patch

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index f41e6b84a1bd..51a4ce094450 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2485,6 +2485,10 @@  scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
 		goto retry;
 	}
 
+	if (data->length > len ||
+	    data->header_length + data->block_descriptor_length > data->length)
+		return 0;
+
 	return result;
 }
 EXPORT_SYMBOL(scsi_mode_sense);