From 71a60cb18b06fb7bdac0caa52f6070a5fd139e8b Mon Sep 17 00:00:00 2001 From: Chen Qun Date: Mon, 21 Jun 2021 10:19:58 +0800 Subject: [PATCH] usb: limit combined packets to 1 MiB (CVE-2021-3527) Fix 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's avatarGerd Hoffmann Message-Id: <20210503132915.2335822-6-kraxel@redhat.com> Signed-off-by: Jiajie Li --- ...bined-packets-to-1-MiB-CVE-2021-3527.patch | 39 +++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 usb-limit-combined-packets-to-1-MiB-CVE-2021-3527.patch diff --git a/usb-limit-combined-packets-to-1-MiB-CVE-2021-3527.patch b/usb-limit-combined-packets-to-1-MiB-CVE-2021-3527.patch new file mode 100644 index 0000000..836e01c --- /dev/null +++ b/usb-limit-combined-packets-to-1-MiB-CVE-2021-3527.patch @@ -0,0 +1,39 @@ +From 93be5f3334394aa9a1794007aed79e75cf4d348b Mon Sep 17 00:00:00 2001 +From: Gerd Hoffmann +Date: Mon, 21 Jun 2021 10:19:58 +0800 +Subject: [PATCH] usb: limit combined packets to 1 MiB (CVE-2021-3527) + +Fix 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's avatarGerd Hoffmann +Message-Id: <20210503132915.2335822-6-kraxel@redhat.com> + +Signed-off-by: Jiajie Li +--- + 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) { +-- +2.27.0 +