[Qemu-devel] [PATCH 11/16] scsi-disk: add data direction checking

[Qemu-devel] [PATCH 11/16] scsi-disk: add data direction checking

[Hannes Reinecke]

scsi_req_parse() already provides for a data direction setting,
so we should be using it to check for correct direction.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 hw/scsi-disk.c |   13 +++++++------
 1 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index fa7b29f..1541524 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -51,8 +51,6 @@ typedef struct SCSIDiskState SCSIDiskState;
 
 typedef struct SCSIDiskReq {
     SCSIRequest req;
-    /* ??? We should probably keep track of whether the data transfer is
-       a read or a write.  Currently we rely on the host getting it right.  */
     /* Both sector and sector_count are in terms of qemu 512 byte blocks.  */
     uint64_t sector;
     uint32_t sector_count;
@@ -182,6 +180,9 @@ static void scsi_read_data(SCSIRequest *req)
     /* No data transfer may already be in progress */
     assert(r->req.aiocb == NULL);
 
+    if (r->req.cmd.mode == SCSI_XFER_TO_DEV)
+        BADF("Data transfer direction invalid\n");
+
     if (r->sector_count == (uint32_t)-1) {
         DPRINTF("Read buf_len=%zd\n", r->iov[0].iov_len);
         r->sector_count = 0;
@@ -294,6 +295,9 @@ static int scsi_write_data(SCSIRequest *req)
     /* No data transfer may already be in progress */
     assert(r->req.aiocb == NULL);
 
+    if (r->req.cmd.mode != SCSI_XFER_TO_DEV)
+        BADF("Data transfer direction invalid\n");
+
     n = scsi_req_iov_len(r) / 512;
     if (n) {
         qemu_iovec_init_external(&r->qiov, r->iov, r->iov_num);
@@ -980,11 +984,9 @@ static int32_t scsi_send_command(SCSIRequest *req, uint8_t *buf)
     SCSIDiskReq *r = DO_UPCAST(SCSIDiskReq, req, req);
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, req->dev);
     ssize_t len = 0;
-    int is_write;
     uint8_t command;
 
     command = buf[0];
-    is_write = 0;
     DPRINTF("Command: lun=%d tag=0x%x data=0x%02x", lun, tag, buf[0]);
 
     if (scsi_req_parse(&r->req, buf) != 0) {
@@ -1067,7 +1069,6 @@ static int32_t scsi_send_command(SCSIRequest *req, uint8_t *buf)
             goto illegal_lba;
         }
         r->sector = r->req.cmd.lba * s->cluster_size;
-        is_write = 1;
         break;
     case MODE_SELECT:
         DPRINTF("Mode Select(6) (len %lu)\n", (long)r->req.cmd.xfer);
@@ -1108,7 +1109,7 @@ static int32_t scsi_send_command(SCSIRequest *req, uint8_t *buf)
         scsi_command_complete(r, GOOD, SENSE_CODE(NO_SENSE));
     }
     len += r->sector_count * 512;
-    if (is_write) {
+    if (r->req.cmd.mode == SCSI_XFER_TO_DEV) {
         return -len;
     } else {
         if (!r->sector_count)
-- 
1.7.1

Re: [Qemu-devel] [PATCH 11/16] scsi-disk: add data direction checking

[Christoph Hellwig]

On Thu, Nov 18, 2010 at 03:47:32PM +0100, Hannes Reinecke wrote:
> 
> scsi_req_parse() already provides for a data direction setting,
> so we should be using it to check for correct direction.

Instead of just a debug printf that almost no one compiles in shouldn't
we reject the incorrect commands?

Re: [Qemu-devel] [PATCH 11/16] scsi-disk: add data direction checking

[Hannes Reinecke]

On 11/22/2010 12:20 PM, Christoph Hellwig wrote:
> On Thu, Nov 18, 2010 at 03:47:32PM +0100, Hannes Reinecke wrote:
>>
>> scsi_req_parse() already provides for a data direction setting,
>> so we should be using it to check for correct direction.
> 
> Instead of just a debug printf that almost no one compiles in shouldn't
> we reject the incorrect commands?
> 
Good point. Will be fixing it up for the next version.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)