[PATCH 4.19 035/425] xhci: check control context is valid before dereferencing it.

[Greg Kroah-Hartman]

From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>

[ Upstream commit 597899d2f7c5619c87185ee7953d004bd37fd0eb ]

Don't dereference ctrl_ctx before checking it's valid.
Issue reported by Klockwork

Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210406070208.3406266-3-mathias.nyman@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/usb/host/xhci.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 6c508d0313f7..fc07d68fdd15 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3148,6 +3148,14 @@ static void xhci_endpoint_reset(struct usb_hcd *hcd,
 
 	/* config ep command clears toggle if add and drop ep flags are set */
 	ctrl_ctx = xhci_get_input_control_ctx(cfg_cmd->in_ctx);
+	if (!ctrl_ctx) {
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		xhci_free_command(xhci, cfg_cmd);
+		xhci_warn(xhci, "%s: Could not get input context, bad type.\n",
+				__func__);
+		goto cleanup;
+	}
+
 	xhci_setup_input_ctx_for_config_ep(xhci, cfg_cmd->in_ctx, vdev->out_ctx,
 					   ctrl_ctx, ep_flag, ep_flag);
 	xhci_endpoint_copy(xhci, cfg_cmd->in_ctx, vdev->out_ctx, ep_index);
-- 
2.30.2