| From c114944d7d67f24e71562fcfc18d550ab787e4d4 Mon Sep 17 00:00:00 2001 |
| From: Alan Stern <stern@rowland.harvard.edu> |
| Date: Mon, 22 Apr 2019 11:16:04 -0400 |
| Subject: USB: w1 ds2490: Fix bug caused by improper use of altsetting array |
| |
| 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 |
| @@ -1016,15 +1016,15 @@ 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); |