patch "usb: storage: return on error to avoid a null pointer dereference" added to usb-linus

This is a note to let you know that I've just added the patch titled

usb: storage: return on error to avoid a null pointer dereference

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From: Colin Ian King <[email protected]>
Date: Thu, 6 Jul 2017 16:06:32 +0100
Subject: usb: storage: return on error to avoid a null pointer dereference

When us->extra is null the driver is not initialized, however, a later call to osd200_scsi_to_ata is made that dereferences us->extra, causing a null pointer dereference. The code currently detects and reports that the driver is not initialized; add a return to avoid the subsequent dereference issue in this check.

Thanks to Alan Stern for pointing out that srb->result needs setting to DID_ERROR << 16

Detected by CoverityScan, CID#100308 ("Dereference after null check")

---
 drivers/usb/storage/isd200.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

index fba4005dd737..6a7720e66595 100644
@@ -1529,8 +1529,11 @@ static void isd200_ata_command(struct scsi_cmnd *srb, struct us_data *us)
 
 	/* Make sure driver was initialized */
 
-	if (us->extra == NULL)
+	if (us->extra == NULL) {
 		usb_stor_dbg(us, "ERROR Driver not initialized\n");
+		srb->result = DID_ERROR << 16;
+		return;
+	}
 
 	scsi_set_resid(srb, 0);
 	/* scsi_bufflen might change in protocol translation to ata */

2.13.3