Re: [Bug 1886362] [NEW] Heap use-after-free in lduw_he_p through e1000e_write_to_rx_buffers

[Jason Wang <1886362@bugs.launchpad.net>]

On 2020/7/21 下午8:31, Peter Maydell wrote:
> On Wed, 15 Jul 2020 at 09:36, Jason Wang <jasowang@redhat.com> wrote:
>> I think the point is to make DMA to MMIO work as real hardware.
> I wouldn't care to give a 100% guarantee that asking a real
> h/w device to DMA to itself didn't cause it to misbehave :-)
> It's more likely to happen-to-work because the DMA engine bit
> of a real h/w device is going to be decoupled somewhat from
> the respond-to-memory-transactions-for-registers logic, but
> it probably wasn't something the designers were actively
> thinking about either...


I think some device want such peer to peer transactions:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation
/driver-api/pci/p2pdma.rst


>
>> For
>> e1000e and other networking devices we need make sure such DMA doesn't
>> break anything.
> Yeah, this is the interesting part for QEMU. How should we
> structure devices that do DMA so that we can be sure that
> the device emulation at least doesn't crash? We could have
> a rule that all devices that do DMA must always postpone
> all of that DMA to a bottom-half, but that's a lot of
> refactoring of a lot of device code...


It looks to me the issue happens only for device with loopback

Simply git grep loopback in hw/net tells me we probably need only to 
audit dp8393x and rtl8139.

Qiang, want to help to audit those devices?

Thanks


>
> thanks
> -- PMM
>

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https://bugs.launchpad.net/bugs/1886362

Title:
  Heap use-after-free in lduw_he_p through e1000e_write_to_rx_buffers

Status in QEMU:
  New

Bug description:
  Hello,
  This reproducer causes a heap-use-after free. QEMU Built with --enable-sanitizers:
  cat << EOF | ./i386-softmmu/qemu-system-i386 -M q35,accel=qtest \
  -qtest stdio -nographic -monitor none -serial none
  outl 0xcf8 0x80001010
  outl 0xcfc 0xe1020000
  outl 0xcf8 0x80001014
  outl 0xcf8 0x80001004
  outw 0xcfc 0x7
  outl 0xcf8 0x800010a2
  write 0xe102003b 0x1 0xff
  write 0xe1020103 0x1e 0xffffff055c5e5c30be4511d084ffffffffffffffffffffffffffffffffff
  write 0xe1020420 0x4 0xffffffff
  write 0xe1020424 0x4 0xffffffff
  write 0xe102042b 0x1 0xff
  write 0xe1020430 0x4 0x055c5e5c
  write 0x5c041 0x1 0x04
  write 0x5c042 0x1 0x02
  write 0x5c043 0x1 0xe1
  write 0x5c048 0x1 0x8a
  write 0x5c04a 0x1 0x31
  write 0x5c04b 0x1 0xff
  write 0xe1020403 0x1 0xff
  EOF

  The Output:
  ==22689==ERROR: AddressSanitizer: heap-use-after-free on address 0x62500026800e at pc 0x55b93bb18bfa bp 0x7fffdbe844f0 sp 0x7fffdbe83cb8
  READ of size 2 at 0x62500026800e thread T0
      #0  in __asan_memcpy (/build/i386-softmmu/qemu-system-i386+)
      #1  in lduw_he_p /include/qemu/bswap.h:332:5
      #2  in ldn_he_p /include/qemu/bswap.h:550:1
      #3  in flatview_write_continue /exec.c:3145:19
      #4  in flatview_write /exec.c:3186:14
      #5  in address_space_write /exec.c:3280:18
      #6  in address_space_rw /exec.c:3290:16
      #7  in dma_memory_rw_relaxed /include/sysemu/dma.h:87:18
      #8  in dma_memory_rw /include/sysemu/dma.h:113:12
      #9  in pci_dma_rw /include/hw/pci/pci.h:789:5
      #10  in pci_dma_write /include/hw/pci/pci.h:802:12
      #11  in e1000e_write_to_rx_buffers /hw/net/e1000e_core.c:1412:9
      #12  in e1000e_write_packet_to_guest /hw/net/e1000e_core.c:1582:21
      #13  in e1000e_receive_iov /hw/net/e1000e_core.c:1709:9
      #14  in e1000e_nc_receive_iov /hw/net/e1000e.c:213:12
      #15  in net_tx_pkt_sendv /hw/net/net_tx_pkt.c:544:9
      #16  in net_tx_pkt_send /hw/net/net_tx_pkt.c:620:9
      #17  in net_tx_pkt_send_loopback /hw/net/net_tx_pkt.c:633:11
      #18  in e1000e_tx_pkt_send /hw/net/e1000e_core.c:664:16
      #19  in e1000e_process_tx_desc /hw/net/e1000e_core.c:743:17
      #20  in e1000e_start_xmit /hw/net/e1000e_core.c:934:9
      #21  in e1000e_set_tctl /hw/net/e1000e_core.c:2431:9
      #22  in e1000e_core_write /hw/net/e1000e_core.c:3265:9
      #23  in e1000e_mmio_write /hw/net/e1000e.c:109:5
      #24  in memory_region_write_accessor /memory.c:483:5
      #25  in access_with_adjusted_size /memory.c:544:18
      #26  in memory_region_dispatch_write /memory.c:1476:16
      #27  in flatview_write_continue /exec.c:3146:23
      #28  in flatview_write /exec.c:3186:14
      #29  in address_space_write /exec.c:3280:18
      #30  in qtest_process_command /qtest.c:567:9
      #31  in qtest_process_inbuf /qtest.c:710:9
      #32  in qtest_read /qtest.c:722:5
      #33  in qemu_chr_be_write_impl /chardev/char.c:188:9
      #34  in qemu_chr_be_write /chardev/char.c:200:9
      #35  in fd_chr_read /chardev/char-fd.c:68:9
      #36  in qio_channel_fd_source_dispatch /io/channel-watch.c:84:12
      #37  in g_main_context_dispatch (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+)
      #38  in glib_pollfds_poll /util/main-loop.c:219:9
      #39  in os_host_main_loop_wait /util/main-loop.c:242:5
      #40  in main_loop_wait /util/main-loop.c:518:11
      #41  in qemu_main_loop /softmmu/vl.c:1664:9
      #42  in main /softmmu/main.c:52:5
      #43  in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+)
      #44  in _start (/build/i386-softmmu/qemu-system-i386+)

  0x62500026800e is located 14 bytes inside of 138-byte region [0x625000268000,0x62500026808a)
  freed by thread T0 here:
      #0  in free (/build/i386-softmmu/qemu-system-i386+)
      #1  in qemu_vfree /util/oslib-posix.c:238:5
      #2  in address_space_unmap /exec.c:3616:5
      #3  in dma_memory_unmap /include/sysemu/dma.h:148:5
      #4  in pci_dma_unmap /include/hw/pci/pci.h:839:5
      #5  in net_tx_pkt_reset /hw/net/net_tx_pkt.c:453:9
      #6  in e1000e_process_tx_desc /hw/net/e1000e_core.c:749:9
      #7  in e1000e_start_xmit /hw/net/e1000e_core.c:934:9
      #8  in e1000e_set_tctl /hw/net/e1000e_core.c:2431:9
      #9  in e1000e_core_write /hw/net/e1000e_core.c:3265:9
      #10  in e1000e_mmio_write /hw/net/e1000e.c:109:5
      #11  in memory_region_write_accessor /memory.c:483:5
      #12  in access_with_adjusted_size /memory.c:544:18
      #13  in memory_region_dispatch_write /memory.c:1476:16
      #14  in flatview_write_continue /exec.c:3146:23
      #15  in flatview_write /exec.c:3186:14
      #16  in address_space_write /exec.c:3280:18
      #17  in address_space_rw /exec.c:3290:16
      #18  in dma_memory_rw_relaxed /include/sysemu/dma.h:87:18
      #19  in dma_memory_rw /include/sysemu/dma.h:113:12
      #20  in pci_dma_rw /include/hw/pci/pci.h:789:5
      #21  in pci_dma_write /include/hw/pci/pci.h:802:12
      #22  in e1000e_write_to_rx_buffers /hw/net/e1000e_core.c:1412:9
      #23  in e1000e_write_packet_to_guest /hw/net/e1000e_core.c:1582:21
      #24  in e1000e_receive_iov /hw/net/e1000e_core.c:1709:9
      #25  in e1000e_nc_receive_iov /hw/net/e1000e.c:213:12
      #26  in net_tx_pkt_sendv /hw/net/net_tx_pkt.c:544:9
      #27  in net_tx_pkt_send /hw/net/net_tx_pkt.c:620:9
      #28  in net_tx_pkt_send_loopback /hw/net/net_tx_pkt.c:633:11
      #29  in e1000e_tx_pkt_send /hw/net/e1000e_core.c:664:16

  previously allocated by thread T0 here:
      #0  in posix_memalign (/build/i386-softmmu/qemu-system-i386+)
      #1  in qemu_try_memalign /util/oslib-posix.c:198:11
      #2  in qemu_memalign /util/oslib-posix.c:214:27
      #3  in address_space_map /exec.c:3558:25
      #4  in dma_memory_map /include/sysemu/dma.h:138:9
      #5  in pci_dma_map /include/hw/pci/pci.h:832:11
      #6  in net_tx_pkt_add_raw_fragment /hw/net/net_tx_pkt.c:391:24
      #7  in e1000e_process_tx_desc /hw/net/e1000e_core.c:731:14
      #8  in e1000e_start_xmit /hw/net/e1000e_core.c:934:9
      #9  in e1000e_set_tctl /hw/net/e1000e_core.c:2431:9
      #10  in e1000e_core_write /hw/net/e1000e_core.c:3265:9
      #11  in e1000e_mmio_write /hw/net/e1000e.c:109:5
      #12  in memory_region_write_accessor /memory.c:483:5
      #13  in access_with_adjusted_size /memory.c:544:18
      #14  in memory_region_dispatch_write /memory.c:1476:16
      #15  in flatview_write_continue /exec.c:3146:23
      #16  in flatview_write /exec.c:3186:14
      #17  in address_space_write /exec.c:3280:18
      #18  in qtest_process_command /qtest.c:567:9
      #19  in qtest_process_inbuf /qtest.c:710:9
      #20  in qtest_read /qtest.c:722:5
      #21  in qemu_chr_be_write_impl /chardev/char.c:188:9
      #22  in qemu_chr_be_write /chardev/char.c:200:9
      #23  in fd_chr_read /chardev/char-fd.c:68:9
      #24  in qio_channel_fd_source_dispatch /io/channel-watch.c:84:12
      #25  in g_main_context_dispatch (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+)

  -Alex

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