Linux-USB Archive on lore.kernel.org
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From: Johan Hovold <johan@kernel.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org, Johan Hovold <johan@kernel.org>,
	stable <stable@vger.kernel.org>
Subject: [PATCH 4/4] USB: serial: io_edgeport: fix epic endpoint lookup
Date: Tue, 10 Dec 2019 12:26:01 +0100
Message-ID: <20191210112601.3561-5-johan@kernel.org> (raw)
In-Reply-To: <20191210112601.3561-1-johan@kernel.org>

Make sure to use the current alternate setting when looking up the
endpoints on epic devices to avoid binding to an invalid interface.

Failing to do so could cause the driver to misbehave or trigger a WARN()
in usb_submit_urb() that kernels with panic_on_warn set would choke on.

Fixes: 6e8cf7751f9f ("USB: add EPIC support to the io_edgeport driver")
Cc: stable <stable@vger.kernel.org>     # 2.6.21
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/io_edgeport.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index 48a439298a68..9690a5f4b9d6 100644
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -2901,16 +2901,18 @@ static int edge_startup(struct usb_serial *serial)
 	response = 0;
 
 	if (edge_serial->is_epic) {
+		struct usb_host_interface *alt;
+
+		alt = serial->interface->cur_altsetting;
+
 		/* EPIC thing, set up our interrupt polling now and our read
 		 * urb, so that the device knows it really is connected. */
 		interrupt_in_found = bulk_in_found = bulk_out_found = false;
-		for (i = 0; i < serial->interface->altsetting[0]
-						.desc.bNumEndpoints; ++i) {
+		for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
 			struct usb_endpoint_descriptor *endpoint;
 			int buffer_size;
 
-			endpoint = &serial->interface->altsetting[0].
-							endpoint[i].desc;
+			endpoint = &alt->endpoint[i].desc;
 			buffer_size = usb_endpoint_maxp(endpoint);
 			if (!interrupt_in_found &&
 			    (usb_endpoint_is_int_in(endpoint))) {
-- 
2.24.0


      parent reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-10 11:25 [PATCH 0/4] USB: fix NULL-deref and alternate settings bugs Johan Hovold
2019-12-10 11:25 ` [PATCH 1/4] USB: atm: ueagle-atm: add missing endpoint check Johan Hovold
2019-12-10 11:25 ` [PATCH 2/4] USB: adutux: fix interface sanity check Johan Hovold
2019-12-10 11:26 ` [PATCH 3/4] USB: idmouse: fix interface sanity checks Johan Hovold
2019-12-10 11:26 ` Johan Hovold [this message]

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