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- From 05a40b172e4d691371534828078be47e7fff524c Mon Sep 17 00:00:00 2001
- From: Gerd Hoffmann <kraxel@redhat.com>
- Date: Mon, 3 May 2021 15:29:15 +0200
- Subject: [PATCH] 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>
- Upstream-Status: Backport
- https://gitlab.com/qemu-project/qemu/-/commit/05a40b172e4d691371534828078be47e7fff524c
- CVE: CVE-2021-3527
- Signed-off-by: Chee Yang Lee <chee.yang.lee@intel.com>
- ---
- hw/usb/combined-packet.c | 4 +++-
- 1 file changed, 3 insertions(+), 1 deletion(-)
- diff --git a/hw/usb/combined-packet.c b/hw/usb/combined-packet.c
- index 5d57e883dc..e56802f89a 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) {
- --
- GitLab
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