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| author | Gerd Hoffmann <kraxel@redhat.com> | 2021-05-03 15:29:15 +0200 |
|---|---|---|
| committer | Gerd Hoffmann <kraxel@redhat.com> | 2021-05-05 15:06:01 +0200 |
| commit | 05a40b172e4d691371534828078be47e7fff524c (patch) | |
| tree | 0f9d4d1f4202a5795a340df5ca80a098c956de6a | |
| parent | 06aa50c06c6392084244f8169d34b8e2d9c43ef2 (diff) | |
| download | qemu-05a40b172e4d691371534828078be47e7fff524c.zip qemu-05a40b172e4d691371534828078be47e7fff524c.tar.gz qemu-05a40b172e4d691371534828078be47e7fff524c.tar.bz2 | |
usb: limit combined packets to 1 MiB (CVE-2021-3527)
usb-host and usb-redirect try to batch bulk transfers by combining many
small usb packets into a single, large transfer request, to reduce the
overhead and improve performance.
This patch adds a size limit of 1 MiB for those combined packets to
restrict the host resources the guest can bind that way.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-Id: <20210503132915.2335822-6-kraxel@redhat.com>
| -rw-r--r-- | hw/usb/combined-packet.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/hw/usb/combined-packet.c b/hw/usb/combined-packet.c index 5d57e88..e56802f 100644 --- a/hw/usb/combined-packet.c +++ b/hw/usb/combined-packet.c @@ -171,7 +171,9 @@ void usb_ep_combine_input_packets(USBEndpoint *ep) if ((p->iov.size % ep->max_packet_size) != 0 || !p->short_not_ok || next == NULL || /* Work around for Linux usbfs bulk splitting + migration */ - (totalsize == (16 * KiB - 36) && p->int_req)) { + (totalsize == (16 * KiB - 36) && p->int_req) || + /* Next package may grow combined package over 1MiB */ + totalsize > 1 * MiB - ep->max_packet_size) { usb_device_handle_data(ep->dev, first); assert(first->status == USB_RET_ASYNC); if (first->combined) { |