[Bug 1909247] Re: QEMU: use after free vulnerability in esp_do_dma() in hw/scsi/esp.c

[Mauro Matteo Cascella <1909247@bugs.launchpad.net>]

Note that the use-after-free was found in v5.2.0 and, as far as I can
tell, is not reproducible anymore on master. The ESP/NCR53C9x emulator
(hw/scsi/esp.c) underwent several changes since v5.2.0. By git-
bisecting, it looks like the original reproducer is neutralized after
commit [1]. However, the qtest reproducer (comment #3) seems to be
working fine on master as of today.

[1]
https://git.qemu.org/?p=qemu.git;a=commit;h=bb0bc7bbc9764a5e9e81756819838c5db88652b8

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1909247

Title:
  QEMU: use after free vulnerability in esp_do_dma() in hw/scsi/esp.c

Status in QEMU:
  New

Bug description:
  A use-after-free vulnerability was found in the am53c974 SCSI host bus
  adapter emulation of QEMU. It could occur in the esp_do_dma() function
  in hw/scsi/esp.c while handling the 'Information Transfer' command
  (CMD_TI). A privileged guest user may abuse this flaw to crash the
  QEMU process on the host, resulting in a denial of service or
  potential code execution with the privileges of the QEMU process.

  This issue was reported by Cheolwoo Myung (Seoul National University).

  Original report:
  Using hypervisor fuzzer, hyfuzz, I found a use-after-free issue in
  am53c974 emulator of QEMU enabled ASan.

  It occurs while transferring information, as it does not check the
  buffer to be transferred.

  A malicious guest user/process could use this flaw to crash the QEMU
  process resulting in DoS scenario.

  To reproduce this issue, please run the QEMU with the following command
  line.

  # To enable ASan option, please set configuration with the following
  $ ./configure --target-list=i386-softmmu --disable-werror --enable-sanitizers
  $ make

  # To reproduce this issue, please run the QEMU process with the following command line
  $ ./qemu-system-i386 -m 512 -drive file=./hyfuzz.img,index=0,media=disk,format=raw \
  -device am53c974,id=scsi -device scsi-hd,drive=SysDisk \
  -drive id=SysDisk,if=none,file=./disk.img

  Please find attached the disk images to reproduce this issue.

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1909247/+subscriptions