Patchworkβ quickcam_messenger.c: possible buffer overflow while use strncat.

login
register
about
Submitter iceberg
Date 2009-10-07 15:56:54
Message ID <200910071556.54534.strakh@ispras.ru>
Download mbox | patch
Permalink /patch/52255/
State New
Headers show

Comments

iceberg - 2009-10-07 15:56:54
In driver ./drivers/media/video/usbvideo/quickcam_messenger.c in line 91:
  91         usb_make_path(dev, cam->input_physname, sizeof(cam-
>input_physname));
After this line we use strncat:
  92         strncat(cam->input_physname, "/input0", sizeof(cam-
>input_physname));
 where sizeof(cam->input_physname) returns length of cam->input_phisname 
without length for null-symbol. But this parameter must be -  "maximum numbers 
of bytes to copy", i.e.: sizeof(cam->input_physname)-strlen(cam-
>input_physname)-1.
	In this case, after call to usb_make_path the similar drivers use strlcat. 
Like in: drivers/hid/usbhid/hid-core.c:
1152         usb_make_path(dev, hid->phys, sizeof(hid->phys));
1153         strlcat(hid->phys, "/input", sizeof(hid->phys));

Found by Linux Driver Verification Project.

Use strlcat instead of strncat.

Signed-off-by:Alexander Strakh <strakh@ispras.ru>

---
 	if (!input_dev) {

--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

diff --git a/./a/drivers/media/video/usbvideo/quickcam_messenger.c 
b/./b/drivers/media/video/usbvideo/quickcam_messenger.c
index 803d3e4..c4d1b96 100644
--- a/./a/drivers/media/video/usbvideo/quickcam_messenger.c
+++ b/./b/drivers/media/video/usbvideo/quickcam_messenger.c
@@ -89,7 +89,7 @@  static void qcm_register_input(struct qcm *cam, struct 
usb_device *dev)
 	int error;
 
 	usb_make_path(dev, cam->input_physname, sizeof(cam->input_physname));
-	strncat(cam->input_physname, "/input0", sizeof(cam->input_physname));
+	strlcat(cam->input_physname, "/input0", sizeof(cam->input_physname));
 
 	cam->input = input_dev = input_allocate_device();