cherry-pick: "usb: fix setup_len init (CVE-2020-14364)"

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

debian/patches/extra/0003-usb-fix-setup_len-init-CVE-2020-14364.patch

@@ -0,0 +1,87 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Gerd Hoffmann <kraxel@redhat.com>
+Date: Tue, 25 Aug 2020 07:36:36 +0200
+Subject: [PATCH] usb: fix setup_len init (CVE-2020-14364)
+
+Store calculated setup_len in a local variable, verify it, and only
+write it to the struct (USBDevice->setup_len) in case it passed the
+sanity checks.
+
+This prevents other code (do_token_{in,out} functions specifically)
+from working with invalid USBDevice->setup_len values and overrunning
+the USBDevice->setup_buf[] buffer.
+
+Fixes: CVE-2020-14364
+Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
+Tested-by: Gonglei <arei.gonglei@huawei.com>
+Reviewed-by: Li Qiang <liq3ea@gmail.com>
+Message-id: 20200825053636.29648-1-kraxel@redhat.com
+(cherry picked from commit b946434f2659a182afc17e155be6791ebfb302eb)
+Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
+---
+ hw/usb/core.c | 16 ++++++++++------
+ 1 file changed, 10 insertions(+), 6 deletions(-)
+
+diff --git a/hw/usb/core.c b/hw/usb/core.c
+index 5abd128b6b..5234dcc73f 100644
+--- a/hw/usb/core.c
++++ b/hw/usb/core.c
+@@ -129,6 +129,7 @@ void usb_wakeup(USBEndpoint *ep, unsigned int stream)
+ static void do_token_setup(USBDevice *s, USBPacket *p)
+ {
+     int request, value, index;
++    unsigned int setup_len;
+ 
+     if (p->iov.size != 8) {
+         p->status = USB_RET_STALL;
+@@ -138,14 +139,15 @@ static void do_token_setup(USBDevice *s, USBPacket *p)
+     usb_packet_copy(p, s->setup_buf, p->iov.size);
+     s->setup_index = 0;
+     p->actual_length = 0;
+-    s->setup_len   = (s->setup_buf[7] << 8) | s->setup_buf[6];
+-    if (s->setup_len > sizeof(s->data_buf)) {
++    setup_len = (s->setup_buf[7] << 8) | s->setup_buf[6];
++    if (setup_len > sizeof(s->data_buf)) {
+         fprintf(stderr,
+                 "usb_generic_handle_packet: ctrl buffer too small (%d > %zu)\n",
+-                s->setup_len, sizeof(s->data_buf));
++                setup_len, sizeof(s->data_buf));
+         p->status = USB_RET_STALL;
+         return;
+     }
++    s->setup_len = setup_len;
+ 
+     request = (s->setup_buf[0] << 8) | s->setup_buf[1];
+     value   = (s->setup_buf[3] << 8) | s->setup_buf[2];
+@@ -259,26 +261,28 @@ static void do_token_out(USBDevice *s, USBPacket *p)
+ static void do_parameter(USBDevice *s, USBPacket *p)
+ {
+     int i, request, value, index;
++    unsigned int setup_len;
+ 
+     for (i = 0; i < 8; i++) {
+         s->setup_buf[i] = p->parameter >> (i*8);
+     }
+ 
+     s->setup_state = SETUP_STATE_PARAM;
+-    s->setup_len   = (s->setup_buf[7] << 8) | s->setup_buf[6];
+     s->setup_index = 0;
+ 
+     request = (s->setup_buf[0] << 8) | s->setup_buf[1];
+     value   = (s->setup_buf[3] << 8) | s->setup_buf[2];
+     index   = (s->setup_buf[5] << 8) | s->setup_buf[4];
+ 
+-    if (s->setup_len > sizeof(s->data_buf)) {
++    setup_len = (s->setup_buf[7] << 8) | s->setup_buf[6];
++    if (setup_len > sizeof(s->data_buf)) {
+         fprintf(stderr,
+                 "usb_generic_handle_packet: ctrl buffer too small (%d > %zu)\n",
+-                s->setup_len, sizeof(s->data_buf));
++                setup_len, sizeof(s->data_buf));
+         p->status = USB_RET_STALL;
+         return;
+     }
++    s->setup_len = setup_len;
+ 
+     if (p->pid == USB_TOKEN_OUT) {
+         usb_packet_copy(p, s->data_buf, s->setup_len);

debian/patches/series

@@ -1,5 +1,6 @@
 extra/0001-block-block-copy-always-align-copied-region-to-clust.patch
 extra/0002-Revert-qemu-img-convert-Don-t-pre-zero-images.patch
+extra/0003-usb-fix-setup_len-init-CVE-2020-14364.patch
 pve/0001-PVE-Config-block-file-change-locking-default-to-off.patch
 pve/0002-PVE-Config-Adjust-network-script-path-to-etc-kvm.patch
 pve/0003-PVE-Config-set-the-CPU-model-to-kvm64-32-instead-of-.patch