3.16.62-rc1 review patch. If anyone has any objections, please let me know.
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From: Oliver Neukum oneukum@suse.com
commit 7a68d9fb851012829c29e770621905529bd9490b upstream.
Requesting a ZERO_PACKET or not is sensible only for output. In the input direction the device decides. Likewise accepting short packets makes sense only for input.
This allows operation with panic_on_warn without opening up a local DOS.
Signed-off-by: Oliver Neukum oneukum@suse.com Reported-by: syzbot+843efa30c8821bd69f53@syzkaller.appspotmail.com Fixes: 0cb54a3e47cb ("USB: debugging code shouldn't alter control flow") Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/usb/core/devio.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-)
--- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -1291,10 +1291,13 @@ static int proc_do_submiturb(struct usb_ struct async *as = NULL; struct usb_ctrlrequest *dr = NULL; unsigned int u, totlen, isofrmlen; - int i, ret, is_in, num_sgs = 0, ifnum = -1; + int i, ret, num_sgs = 0, ifnum = -1; int number_of_packets = 0; unsigned int stream_id = 0; void *buf; + bool is_in; + bool allow_short = false; + bool allow_zero = false; unsigned long mask = USBDEVFS_URB_SHORT_NOT_OK | USBDEVFS_URB_BULK_CONTINUATION | USBDEVFS_URB_NO_FSBR | @@ -1326,6 +1329,8 @@ static int proc_do_submiturb(struct usb_ u = 0; switch(uurb->type) { case USBDEVFS_URB_TYPE_CONTROL: + if (is_in) + allow_short = true; if (!usb_endpoint_xfer_control(&ep->desc)) return -EINVAL; /* min 8 byte setup packet */ @@ -1366,6 +1371,10 @@ static int proc_do_submiturb(struct usb_ break;
case USBDEVFS_URB_TYPE_BULK: + if (!is_in) + allow_zero = true; + else + allow_short = true; switch (usb_endpoint_type(&ep->desc)) { case USB_ENDPOINT_XFER_CONTROL: case USB_ENDPOINT_XFER_ISOC: @@ -1386,6 +1395,10 @@ static int proc_do_submiturb(struct usb_ if (!usb_endpoint_xfer_int(&ep->desc)) return -EINVAL; interrupt_urb: + if (!is_in) + allow_zero = true; + else + allow_short = true; break;
case USBDEVFS_URB_TYPE_ISO: @@ -1515,11 +1528,11 @@ static int proc_do_submiturb(struct usb_ u = (is_in ? URB_DIR_IN : URB_DIR_OUT); if (uurb->flags & USBDEVFS_URB_ISO_ASAP) u |= URB_ISO_ASAP; - if (uurb->flags & USBDEVFS_URB_SHORT_NOT_OK && is_in) + if (allow_short && uurb->flags & USBDEVFS_URB_SHORT_NOT_OK) u |= URB_SHORT_NOT_OK; if (uurb->flags & USBDEVFS_URB_NO_FSBR) u |= URB_NO_FSBR; - if (uurb->flags & USBDEVFS_URB_ZERO_PACKET) + if (allow_zero && uurb->flags & USBDEVFS_URB_ZERO_PACKET) u |= URB_ZERO_PACKET; if (uurb->flags & USBDEVFS_URB_NO_INTERRUPT) u |= URB_NO_INTERRUPT;