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 the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: usb-storage-return-on-error-to-avoid-a-null-pointer-dereference.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 446230f52a5bef593554510302465eabab45a372 Mon Sep 17 00:00:00 2001 From: Colin Ian King <colin.king@xxxxxxxxxxxxx> Date: Thu, 6 Jul 2017 16:06:32 +0100 Subject: usb: storage: return on error to avoid a null pointer dereference From: Colin Ian King <colin.king@xxxxxxxxxxxxx> commit 446230f52a5bef593554510302465eabab45a372 upstream. 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") Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx> Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/storage/isd200.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/drivers/usb/storage/isd200.c +++ b/drivers/usb/storage/isd200.c @@ -1520,8 +1520,11 @@ static void isd200_ata_command(struct sc /* 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 */ Patches currently in stable-queue which might be from colin.king@xxxxxxxxxxxxx are queue-4.4/usb-storage-return-on-error-to-avoid-a-null-pointer-dereference.patch