4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Johannes Thumshirn <jthumshirn@xxxxxxx>
commit f930c7043663188429cd9b254e9d761edfc101ce upstream.
Don't make any assumptions on the sg_io_hdr_t::dxfer_direction or the
sg_io_hdr_t::dxferp in order to determine if it is a valid request. The
only way we can check for bad requests is by checking if the length
exceeds 256M.
Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
Fixes: 28676d869bbb (scsi: sg: check for valid direction before starting the request)
Reported-by: Jason L Tibbitts III <tibbs@xxxxxxxxxxx>
Tested-by: Jason L Tibbitts III <tibbs@xxxxxxxxxxx>
Suggested-by: Doug Gilbert <dgilbert@xxxxxxxxxxxx>
Cc: Doug Gilbert <dgilbert@xxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/scsi/sg.c | 31 +------------------------------
1 file changed, 1 insertion(+), 30 deletions(-)
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -762,35 +762,6 @@ sg_new_write(Sg_fd *sfp, struct file *fi
return count;
}
-static bool sg_is_valid_dxfer(sg_io_hdr_t *hp)
-{
- switch (hp->dxfer_direction) {
- case SG_DXFER_NONE:
- if (hp->dxferp || hp->dxfer_len > 0)
- return false;
- return true;
- case SG_DXFER_FROM_DEV:
- /*
- * for SG_DXFER_FROM_DEV we always set dxfer_len to > 0. dxferp
- * can either be NULL or != NULL so there's no point in checking
- * it either. So just return true.
- */
- return true;
- case SG_DXFER_TO_DEV:
- case SG_DXFER_TO_FROM_DEV:
- if (!hp->dxferp || hp->dxfer_len == 0)
- return false;
- return true;
- case SG_DXFER_UNKNOWN:
- if ((!hp->dxferp && hp->dxfer_len) ||
- (hp->dxferp && hp->dxfer_len == 0))
- return false;
- return true;
- default:
- return false;
- }
-}
-
static int
sg_common_write(Sg_fd * sfp, Sg_request * srp,
unsigned char *cmnd, int timeout, int blocking)
@@ -811,7 +782,7 @@ sg_common_write(Sg_fd * sfp, Sg_request
"sg_common_write: scsi opcode=0x%02x, cmd_size=%d\n",
(int) cmnd[0], (int) hp->cmd_len));
- if (!sg_is_valid_dxfer(hp))
+ if (hp->dxfer_len >= SZ_256M)
return -EINVAL;
k = sg_start_req(srp, cmnd);