hw: xhci: check return value of 'usb_packet_map'

Currently we don't check the return value of 'usb_packet_map',
this will cause an UAF issue. This is LP#1891341.
Following is the reproducer provided in:
-->https://bugs.launchpad.net/qemu/+bug/1891341

cat << EOF | ./i386-softmmu/qemu-system-i386 -device nec-usb-xhci \
-trace usb\* -device usb-audio -device usb-storage,drive=mydrive \
-drive id=mydrive,file=null-co://,size=2M,format=raw,if=none \
-nodefaults -nographic -qtest stdio
outl 0xcf8 0x80001016
outl 0xcfc 0x3c009f0d
outl 0xcf8 0x80001004
outl 0xcfc 0xc77695e
writel 0x9f0d000000000040 0xffff3655
writeq 0x9f0d000000002000 0xff2f9e0000000000
write 0x1d 0x1 0x27
write 0x2d 0x1 0x2e
write 0x17232 0x1 0x03
write 0x17254 0x1 0x06
write 0x17278 0x1 0x34
write 0x3d 0x1 0x27
write 0x40 0x1 0x2e
write 0x41 0x1 0x72
write 0x42 0x1 0x01
write 0x4d 0x1 0x2e
write 0x4f 0x1 0x01
writeq 0x9f0d000000002000 0x5c051a0100000000
write 0x34001d 0x1 0x13
write 0x340026 0x1 0x30
write 0x340028 0x1 0x08
write 0x34002c 0x1 0xfe
write 0x34002d 0x1 0x08
write 0x340037 0x1 0x5e
write 0x34003a 0x1 0x05
write 0x34003d 0x1 0x05
write 0x34004d 0x1 0x13
writeq 0x9f0d000000002000 0xff00010100400009
EOF

This patch fixes this.

Buglink: https://bugs.launchpad.net/qemu/+bug/1891341
Reported-by: Alexander Bulekov <alxndr@bu.edu>
Signed-off-by: Li Qiang <liq3ea@163.com>
Message-id: 20200812153139.15146-1-liq3ea@163.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
index 67a18fe2b6..46a2186d91 100644
--- a/hw/usb/hcd-xhci.c
+++ b/hw/usb/hcd-xhci.c
@@ -1615,7 +1615,10 @@ static int xhci_setup_packet(XHCITransfer *xfer)
     xhci_xfer_create_sgl(xfer, dir == USB_TOKEN_IN); /* Also sets int_req */
     usb_packet_setup(&xfer->packet, dir, ep, xfer->streamid,
                      xfer->trbs[0].addr, false, xfer->int_req);
-    usb_packet_map(&xfer->packet, &xfer->sgl);
+    if (usb_packet_map(&xfer->packet, &xfer->sgl)) {
+        qemu_sglist_destroy(&xfer->sgl);
+        return -1;
+    }
     DPRINTF("xhci: setup packet pid 0x%x addr %d ep %d\n",
             xfer->packet.pid, ep->dev->addr, ep->nr);
     return 0;