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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Mathias Nyman <mathias.nyman@linux.intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.12 104/384] xhci: check control context is valid before dereferencing it.
Date:   Mon, 10 May 2021 12:18:13 +0200
Message-Id: <20210510102018.311627398@linuxfoundation.org>
In-Reply-To: <20210510102014.849075526@linuxfoundation.org>
References: <20210510102014.849075526@linuxfoundation.org>
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From: Mathias Nyman <mathias.nyman@linux.intel.com>

[ Upstream commit 597899d2f7c5619c87185ee7953d004bd37fd0eb ]

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

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210406070208.3406266-3-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 1975016f46bf..5df780d55df0 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3269,6 +3269,14 @@ 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