Hi Doug,
On 11/11/22 10:53 pm, Douglas Gilbert wrote:
On 2022-11-11 05:05, Harshit Mogalapalli wrote:
As 'lbdof_blen' is coming from user, if the size in kzalloc()
is >= MAX_ORDER then we hit a warning.
Call trace:
sg_ioctl
sg_ioctl_common
scsi_ioctl
sg_scsi_ioctl
blk_execute_rq
blk_mq_sched_insert_request
blk_mq_run_hw_queue
__blk_mq_delay_run_hw_queue
__blk_mq_run_hw_queue
blk_mq_sched_dispatch_requests
__blk_mq_sched_dispatch_requests
blk_mq_dispatch_rq_list
scsi_queue_rq
scsi_dispatch_cmd
scsi_debug_queuecommand
schedule_resp
resp_write_scat
If you try to allocate a memory larger than(>=) MAX_ORDER, then kmalloc()
will definitely fail. It creates a stack trace and messes up dmesg.
The user controls the size here so if they specify a too large size it
will fail.
Add __GFP_NOWARN in order to avoid too large allocation warning.
This is detected by static analysis using smatch.
Fixes: 481b5e5c7949 ("scsi: scsi_debug: add resp_write_scat function")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
Acked-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
Thank you very much for checking the patch.
We have two more similar cases in the scsi_debug.c file in resp_verify()
and resp_report_zones() functions. These are also detected using static
analysis with smatch.
I have sent out patches for those.
Thanks,
Harshit
Thanks.
---
drivers/scsi/scsi_debug.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 697fc57bc711..273224d29ce9 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -3778,7 +3778,7 @@ static int resp_write_scat(struct scsi_cmnd *scp,
mk_sense_buffer(scp, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB, 0);
return illegal_condition_result;
}
- lrdp = kzalloc(lbdof_blen, GFP_ATOMIC);
+ lrdp = kzalloc(lbdof_blen, GFP_ATOMIC | __GFP_NOWARN);
if (lrdp == NULL)
return SCSI_MLQUEUE_HOST_BUSY;
if (sdebug_verbose)
