On Wed, Jun 28, 2017 at 09:18:37PM +0300, Laurent Pinchart wrote: > Hi Guenter, > > On Wednesday 28 Jun 2017 20:59:17 Laurent Pinchart wrote: > > On Wednesday 28 Jun 2017 07:36:43 Guenter Roeck wrote: > > > On Mon, May 22, 2017 at 12:48:04PM -0700, Guenter Roeck wrote: > > >> From: Robb Glasser <rglasser@xxxxxxxxxx> > > >> > > >> The size of uvc_control_mapping is user controlled leading to a > > >> potential heap overflow in the uvc driver. This adds a check to verify > > >> the user provided size fits within the bounds of the defined buffer > > >> size. > > >> > > >> Signed-off-by: Robb Glasser <rglasser@xxxxxxxxxx> > > >> [groeck: cherry picked from > > >> > > >> https://source.codeaurora.org/quic/la/kernel/msm-3.10 > > >> commit b7b99e55bc7770187913ed092990852ea52d7892; > > >> updated subject] > > >> > > >> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx> > > >> --- > > >> Fixes CVE-2017-0627. > > > > > > Please do not apply this patch. It is buggy. > > > > I apologize for not noticing the initial patch, even if it looks like it was > > all for the best. Will you send a new version ? > > > > >> drivers/media/usb/uvc/uvc_ctrl.c | 3 +++ > > >> 1 file changed, 3 insertions(+) > > >> > > >> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c > > >> b/drivers/media/usb/uvc/uvc_ctrl.c index c2ee6e39fd0c..252ab991396f > > >> 100644 > > >> --- a/drivers/media/usb/uvc/uvc_ctrl.c > > >> +++ b/drivers/media/usb/uvc/uvc_ctrl.c > > >> @@ -1992,6 +1992,9 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain > > >> *chain, > > >> if (!found) > > >> return -ENOENT; > > >> > > >> + if (ctrl->info.size < mapping->size) > > >> + return -EINVAL; > > >> + > > By the way, I believe the right fix should be > > if (mapping->offset + mapping->size > ctrl->info.size * 8) > return -EINVAL; > > Both mapping->offset and mapping->size are 8-bit integers, so there's no risk > of overflow in the addition. If we want to safeguard against a possible future > bug if the type of the fields change, we could add > > if (mapping->offset + mapping->size < mapping->offset) > return -EINVAL; > I currently have this: @@ -2004,6 +2004,13 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain *chain, goto done; } + /* validate that the user provided bit-size and offset is valid */ + if ((mapping->size > 32) || + ((mapping->offset + mapping->size) > (ctrl->info.size * 8))) { + ret = -EINVAL; + goto done; + } + list_for_each_entry(map, &ctrl->info.mappings, list) { if (mapping->id == map->id) { uvc_trace(UVC_TRACE_CONTROL, "Can't add mapping '%s', " This version originates from Richard Simmons. Copying him to see if he wants to submit it himself. Guenter
