Andrew Geissler | 5f35090 | 2021-07-23 13:09:54 -0400 | [diff] [blame] | 1 | From 05a40b172e4d691371534828078be47e7fff524c Mon Sep 17 00:00:00 2001 |
| 2 | From: Gerd Hoffmann <kraxel@redhat.com> |
| 3 | Date: Mon, 3 May 2021 15:29:15 +0200 |
| 4 | Subject: [PATCH] usb: limit combined packets to 1 MiB (CVE-2021-3527) |
| 5 | |
| 6 | usb-host and usb-redirect try to batch bulk transfers by combining many |
| 7 | small usb packets into a single, large transfer request, to reduce the |
| 8 | overhead and improve performance. |
| 9 | |
| 10 | This patch adds a size limit of 1 MiB for those combined packets to |
| 11 | restrict the host resources the guest can bind that way. |
| 12 | |
| 13 | Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> |
| 14 | Message-Id: <20210503132915.2335822-6-kraxel@redhat.com> |
| 15 | |
| 16 | Upstream-Status: Backport |
| 17 | https://gitlab.com/qemu-project/qemu/-/commit/05a40b172e4d691371534828078be47e7fff524c |
| 18 | CVE: CVE-2021-3527 |
| 19 | Signed-off-by: Chee Yang Lee <chee.yang.lee@intel.com> |
| 20 | |
| 21 | --- |
| 22 | hw/usb/combined-packet.c | 4 +++- |
| 23 | 1 file changed, 3 insertions(+), 1 deletion(-) |
| 24 | |
| 25 | diff --git a/hw/usb/combined-packet.c b/hw/usb/combined-packet.c |
| 26 | index 5d57e883dc..e56802f89a 100644 |
| 27 | --- a/hw/usb/combined-packet.c |
| 28 | +++ b/hw/usb/combined-packet.c |
| 29 | @@ -171,7 +171,9 @@ void usb_ep_combine_input_packets(USBEndpoint *ep) |
| 30 | if ((p->iov.size % ep->max_packet_size) != 0 || !p->short_not_ok || |
| 31 | next == NULL || |
| 32 | /* Work around for Linux usbfs bulk splitting + migration */ |
| 33 | - (totalsize == (16 * KiB - 36) && p->int_req)) { |
| 34 | + (totalsize == (16 * KiB - 36) && p->int_req) || |
| 35 | + /* Next package may grow combined package over 1MiB */ |
| 36 | + totalsize > 1 * MiB - ep->max_packet_size) { |
| 37 | usb_device_handle_data(ep->dev, first); |
| 38 | assert(first->status == USB_RET_ASYNC); |
| 39 | if (first->combined) { |
| 40 | -- |
| 41 | GitLab |
| 42 | |