From: Alan Stern stern@rowland.harvard.edu
commit c114944d7d67f24e71562fcfc18d550ab787e4d4 upstream.
The syzkaller USB fuzzer spotted a slab-out-of-bounds bug in the ds2490 driver. This bug is caused by improper use of the altsetting array in the usb_interface structure (the array's entries are not always stored in numerical order), combined with a naive assumption that all interfaces probed by the driver will have the expected number of altsettings.
The bug can be fixed by replacing references to the possibly non-existent intf->altsetting[alt] entry with the guaranteed-to-exist intf->cur_altsetting entry.
Signed-off-by: Alan Stern stern@rowland.harvard.edu Reported-and-tested-by: syzbot+d65f673b847a1a96cdba@syzkaller.appspotmail.com CC: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/w1/masters/ds2490.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/w1/masters/ds2490.c +++ b/drivers/w1/masters/ds2490.c @@ -1039,15 +1039,15 @@ static int ds_probe(struct usb_interface /* alternative 3, 1ms interrupt (greatly speeds search), 64 byte bulk */ alt = 3; err = usb_set_interface(dev->udev, - intf->altsetting[alt].desc.bInterfaceNumber, alt); + intf->cur_altsetting->desc.bInterfaceNumber, alt); if (err) { dev_err(&dev->udev->dev, "Failed to set alternative setting %d " "for %d interface: err=%d.\n", alt, - intf->altsetting[alt].desc.bInterfaceNumber, err); + intf->cur_altsetting->desc.bInterfaceNumber, err); goto err_out_clear; }
- iface_desc = &intf->altsetting[alt]; + iface_desc = intf->cur_altsetting; if (iface_desc->desc.bNumEndpoints != NUM_EP-1) { pr_info("Num endpoints=%d. It is not DS9490R.\n", iface_desc->desc.bNumEndpoints);