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Re: [PATCH] xhci: check return value from usb_packet_map
From: |
Alexander Bulekov |
Subject: |
Re: [PATCH] xhci: check return value from usb_packet_map |
Date: |
Sun, 30 Aug 2020 11:27:41 -0400 |
I think there is already a fix queued for this one:
https://www.mail-archive.com/qemu-devel@nongnu.org/msg734424.html
On 200827 1729, P J P wrote:
> 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
>
>