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[PATCH] xhci: check return value from usb_packet_map
From: |
P J P |
Subject: |
[PATCH] xhci: check return value from usb_packet_map |
Date: |
Thu, 27 Aug 2020 17:29:33 +0530 |
From: Prasad J Pandit <pjp@fedoraproject.org>
While setting up a packet in xhci_setup_packet() routine,
usb_packet_map() may return an error. Check this return value
before further processing the packet, to avoid use-after-free
issue.
-> https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Fxhci_uaf_2
#0 __interceptor_free (/lib64/libasan.so.6+0xb0307)
#1 qemu_vfree ../util/oslib-posix.c:247
#2 address_space_unmap ../exec.c:3635
#3 dma_memory_unmap ../include/sysemu/dma.h:145
#4 usb_packet_unmap ../hw/usb/libhw.c:65
#5 usb_packet_map ../hw/usb/libhw.c:54
#6 xhci_setup_packet ../hw/usb/hcd-xhci.c:1618
#7 xhci_fire_ctl_transfer ../hw/usb/hcd-xhci.c:1722
#8 xhci_kick_epctx ../hw/usb/hcd-xhci.c:1991
#9 xhci_kick_ep ../hw/usb/hcd-xhci.c:1861
#10 xhci_doorbell_write ../hw/usb/hcd-xhci.c:3162
...
Reported-by: Ruhr-University <bugs-syssec@rub.de>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
---
hw/usb/hcd-xhci.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
index 67a18fe2b6..848e7e935f 100644
--- a/hw/usb/hcd-xhci.c
+++ b/hw/usb/hcd-xhci.c
@@ -1615,7 +1615,14 @@ 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) < 0) {
+ DPRINTF("xhci: setup packet failed: pid: 0x%x addr %d ep %d\n",
+ xfer->packet.pid, ep->dev->addr, ep->nr);
+ usb_packet_cleanup(&xfer->packet);
+ 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;
--
2.26.2
- [PATCH] xhci: check return value from usb_packet_map,
P J P <=