| Message ID | 20210607152307.GD1768031@rowland.harvard.edu (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 60dfe484cef45293e631b3a6e8995f1689818172 |
| Headers | show |
| Series | [v2] USB: core: Avoid WARNings for 0-length descriptor requests | expand |
On Mon, Jun 07, 2021 at 11:23:07AM -0400, Alan Stern wrote: > The USB core has utility routines to retrieve various types of > descriptors. These routines will now provoke a WARN if they are asked > to retrieve 0 bytes (USB "receive" requests must not have zero > length), so avert this by checking the size argument at the start. > > Reported-and-tested-by: syzbot+7dbcd9ff34dc4ed45240@syzkaller.appspotmail.com > Signed-off-by: Alan Stern <stern@rowland.harvard.edu> > CC: Johan Hovold <johan@kernel.org> > > --- > > v2: Added extra blank lines following the sanity tests. Even better. Reviewed-by: Johan Hovold <johan@kernel.org> > drivers/usb/core/message.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > Index: usb-devel/drivers/usb/core/message.c > =================================================================== > --- usb-devel.orig/drivers/usb/core/message.c > +++ usb-devel/drivers/usb/core/message.c > @@ -783,6 +783,9 @@ int usb_get_descriptor(struct usb_device > int i; > int result; > > + if (size <= 0) /* No point in asking for no data */ > + return -EINVAL; > + > memset(buf, 0, size); /* Make sure we parse really received data */ > > for (i = 0; i < 3; ++i) { > @@ -832,6 +835,9 @@ static int usb_get_string(struct usb_dev > int i; > int result; > > + if (size <= 0) /* No point in asking for no data */ > + return -EINVAL; > + > for (i = 0; i < 3; ++i) { > /* retry on length 0 or stall; some devices are flakey */ > result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), >
Index: usb-devel/drivers/usb/core/message.c =================================================================== --- usb-devel.orig/drivers/usb/core/message.c +++ usb-devel/drivers/usb/core/message.c @@ -783,6 +783,9 @@ int usb_get_descriptor(struct usb_device int i; int result; + if (size <= 0) /* No point in asking for no data */ + return -EINVAL; + memset(buf, 0, size); /* Make sure we parse really received data */ for (i = 0; i < 3; ++i) { @@ -832,6 +835,9 @@ static int usb_get_string(struct usb_dev int i; int result; + if (size <= 0) /* No point in asking for no data */ + return -EINVAL; + for (i = 0; i < 3; ++i) { /* retry on length 0 or stall; some devices are flakey */ result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
The USB core has utility routines to retrieve various types of descriptors. These routines will now provoke a WARN if they are asked to retrieve 0 bytes (USB "receive" requests must not have zero length), so avert this by checking the size argument at the start. Reported-and-tested-by: syzbot+7dbcd9ff34dc4ed45240@syzkaller.appspotmail.com Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: Johan Hovold <johan@kernel.org> --- v2: Added extra blank lines following the sanity tests. [as1962b] drivers/usb/core/message.c | 6 ++++++ 1 file changed, 6 insertions(+)