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staging: gigaset: fix crashes on probe

PATCH New Johan Hovold 1 participant 4 messages Dec 2, 2019

Subsystems (3)
Stable branch USB Staging
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Johan Hovold

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#0 lore raw

v2 cover staging: gigaset: fix crashes on probe

Syzbot has been reporting a GPF on probe in the gigaset ISDN driver, which have since been moved to staging.

The first patch fixes that issue, and the next one fixes a second crash found during testing.

The third patch addresses a benign warning in USB core which syzbot is bound to report once the crashes have been fixed.

Johan

Changes in v2
- use usb_endpoint_is_bulk_out() and friends in patch 3/3, and drop patch 4/4 which only renamed an identifier.

Johan Hovold (3):
staging: gigaset: fix general protection fault on probe
staging: gigaset: fix illegal free on probe errors
staging: gigaset: add endpoint-type sanity check

 drivers/staging/isdn/gigaset/usb-gigaset.c | 23 +++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)
Signature · 1 line
2.24.0
author
#1 lore raw

PATCH v2 1/3 staging: gigaset: fix general protection fault on probe

Fix a general protection fault when accessing the endpoint descriptors which could be triggered by a malicious device due to missing sanity checks on the number of endpoints.

Reported-by [email protected]
Fixes 07dc1f9f2f80 ("[PATCH] isdn4linux: Siemens Gigaset drivers - M105 USB DECT adapter")
Cc stable <[email protected]> # 2.6.17
Cc Hansjoerg Lipp <[email protected]>
Cc Tilman Schmidt <[email protected]>
Signed-off-by Johan Hovold <[email protected]>
---
 drivers/staging/isdn/gigaset/usb-gigaset.c | 5 +++++
 1 file changed, 5 insertions(+)
drivers/staging/isdn/gigaset/usb-gigaset.c +5 -0
index 1b9b43659bdf..5e393e7dde45 100644
@@ -685,6 +685,11 @@ static int gigaset_probe(struct usb_interface *interface,
 		return -ENODEV;
 	}
 
+	if (hostif->desc.bNumEndpoints < 2) {
+		dev_err(&interface->dev, "missing endpoints\n");
+		return -ENODEV;
+	}
+
 	dev_info(&udev->dev, "%s: Device matched ... !\n", __func__);
 
 	/* allocate memory for our device state and initialize it */
Signature · 1 line
2.24.0
author
#2 lore raw

PATCH v2 2/3 staging: gigaset: fix illegal free on probe errors

In reply to Johan Hovold

The driver failed to initialise its receive-buffer pointer, something which could lead to an illegal free on late probe errors.

Fix this by making sure to clear all driver data at allocation.

Fixes 2032e2c2309d ("usb_gigaset: code cleanup")
Cc stable <[email protected]> # 2.6.33
Cc Tilman Schmidt <[email protected]>
Signed-off-by Johan Hovold <[email protected]>
---
 drivers/staging/isdn/gigaset/usb-gigaset.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)
drivers/staging/isdn/gigaset/usb-gigaset.c +1 -5
index 5e393e7dde45..a84722d83bc6 100644
@@ -571,8 +571,7 @@ static int gigaset_initcshw(struct cardstate *cs)
 {
 	struct usb_cardstate *ucs;
 
-	cs->hw.usb = ucs =
-		kmalloc(sizeof(struct usb_cardstate), GFP_KERNEL);
+	cs->hw.usb = ucs = kzalloc(sizeof(struct usb_cardstate), GFP_KERNEL);
 	if (!ucs) {
 		pr_err("out of memory\n");
 		return -ENOMEM;

@@ -584,9 +583,6 @@ static int gigaset_initcshw(struct cardstate *cs)
 	ucs->bchars[3] = 0;
 	ucs->bchars[4] = 0x11;
 	ucs->bchars[5] = 0x13;
-	ucs->bulk_out_buffer = NULL;
-	ucs->bulk_out_urb = NULL;
-	ucs->read_urb = NULL;
 	tasklet_init(&cs->write_tasklet,
 		     gigaset_modem_fill, (unsigned long) cs);
Signature · 1 line
2.24.0
author
#3 lore raw

PATCH v2 3/3 staging: gigaset: add endpoint-type sanity check

In reply to Johan Hovold

Add missing endpoint-type sanity checks to probe.

This specifically prevents a warning in USB core on URB submission when fuzzing USB descriptors.

Signed-off-by Johan Hovold <[email protected]>
---
 drivers/staging/isdn/gigaset/usb-gigaset.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)
drivers/staging/isdn/gigaset/usb-gigaset.c +12 -0
index a84722d83bc6..a20c0bfa68f3 100644
@@ -705,6 +705,12 @@ static int gigaset_probe(struct usb_interface *interface,
 
 	endpoint = &hostif->endpoint[0].desc;
 
+	if (!usb_endpoint_is_bulk_out(endpoint)) {
+		dev_err(&interface->dev, "missing bulk-out endpoint\n");
+		retval = -ENODEV;
+		goto error;
+	}
+
 	buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
 	ucs->bulk_out_size = buffer_size;
 	ucs->bulk_out_epnum = usb_endpoint_num(endpoint);

@@ -724,6 +730,12 @@ static int gigaset_probe(struct usb_interface *interface,
 
 	endpoint = &hostif->endpoint[1].desc;
 
+	if (!usb_endpoint_is_int_in(endpoint)) {
+		dev_err(&interface->dev, "missing int-in endpoint\n");
+		retval = -ENODEV;
+		goto error;
+	}
+
 	ucs->busy = 0;
 
 	ucs->read_urb = usb_alloc_urb(0, GFP_KERNEL);
Signature · 1 line
2.24.0