Skip to contentSkip to conversation

konicawc.c: possible buffer overflow while use strncat.

PATCH New Alexander Strakh 1 participant 1 message Oct 7, 2009 Media (V4L/DVB)

lore
Share & tools
lore
#0 lore raw

PATCH 1/1 konicawc.c: possible buffer overflow while use strncat.

In driver ./drivers/media/video/usbvideo/konicawc.c in line 227:
227 usb_make_path(dev, cam->input_physname, sizeof(cam-

Quoted 1 line

input_physname));

After this line we use strncat:
228 strncat(cam->input_physname, "/input0", sizeof(cam-

Quoted 1 line

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-

Quoted 1 line

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.

---

(quoted diff) +0 -0

b/./b/drivers/media/video/usbvideo/konicawc.c
index 31d57f2..a0addcb 100644

./b/drivers/media/video/usbvideo/konicawc.c renamed from ./a/drivers/media/video/usbvideo/konicawc.c +0 -0
@@ -225,7 +225,7 @@ static void konicawc_register_input(struct konicawc *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(); if (!input_dev) {