[Qemu-commits] [qemu/qemu] 662d0c: block/crypto: disallow write sharing by default

[Peter Maydell]

  Branch: refs/heads/master
  Home:   https://github.com/qemu/qemu
  Commit: 662d0c5392a272aa0357aa7205e77fa3ca89c316
      
https://github.com/qemu/qemu/commit/662d0c5392a272aa0357aa7205e77fa3ca89c316
  Author: Maxim Levitsky <mlevitsk@redhat.com>
  Date:   2020-07-21 (Tue, 21 Jul 2020)

  Changed paths:
    M block/crypto.c

  Log Message:
  -----------
  block/crypto: disallow write sharing by default

My commit 'block/crypto: implement the encryption key management'
accidently allowed raw luks images to be shared between different
qemu processes without share-rw=on explicit override.
Fix that.

Fixes: bbfdae91fb ("block/crypto: implement the encryption key management")
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1857490

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20200719122059.59843-2-mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>


  Commit: 0fca43de1b617a95f2472691ca1e740932ab2fea
      
https://github.com/qemu/qemu/commit/0fca43de1b617a95f2472691ca1e740932ab2fea
  Author: Maxim Levitsky <mlevitsk@redhat.com>
  Date:   2020-07-21 (Tue, 21 Jul 2020)

  Changed paths:
    M tests/qemu-iotests/296
    M tests/qemu-iotests/296.out

  Log Message:
  -----------
  qemu-iotests: add testcase for bz #1857490

Test that we can't write-share raw luks images by default,
but we still can with share-rw=on

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20200719122059.59843-3-mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>


  Commit: 1d719ddc35e9827b6e5df771555874df34301a0d
      
https://github.com/qemu/qemu/commit/1d719ddc35e9827b6e5df771555874df34301a0d
  Author: Stefan Hajnoczi <stefanha@redhat.com>
  Date:   2020-07-21 (Tue, 21 Jul 2020)

  Changed paths:
    M block/block-backend.c

  Log Message:
  -----------
  block: fix bdrv_aio_cancel() for ENOMEDIUM requests

bdrv_aio_cancel() calls aio_poll() on the AioContext for the given I/O
request until it has completed. ENOMEDIUM requests are special because
there is no BlockDriverState when the drive has no medium!

Define a .get_aio_context() function for BlkAioEmAIOCB requests so that
bdrv_aio_cancel() can find the AioContext where the completion BH is
pending. Without this function bdrv_aio_cancel() aborts on ENOMEDIUM
requests!

libFuzzer triggered the following assertion:

  cat << EOF | qemu-system-i386 -M pc-q35-5.0 \
    -nographic -monitor none -serial none \
    -qtest stdio -trace ide\*
  outl 0xcf8 0x8000fa24
  outl 0xcfc 0xe106c000
  outl 0xcf8 0x8000fa04
  outw 0xcfc 0x7
  outl 0xcf8 0x8000fb20
  write 0x0 0x3 0x2780e7
  write 0xe106c22c 0xd 0x1130c218021130c218021130c2
  write 0xe106c218 0x15 0x110010110010110010110010110010110010110010
  EOF
  ide_exec_cmd IDE exec cmd: bus 0x56170a77a2b8; state 0x56170a77a340; cmd 0xe7
  ide_reset IDEstate 0x56170a77a340
  Aborted (core dumped)

  (gdb) bt
  #1  0x00007ffff4f93895 in abort () at /lib64/libc.so.6
  #2  0x0000555555dc6c00 in bdrv_aio_cancel (acb=0x555556765550) at 
block/io.c:2745
  #3  0x0000555555dac202 in blk_aio_cancel (acb=0x555556765550) at 
block/block-backend.c:1546
  #4  0x0000555555b1bd74 in ide_reset (s=0x555557213340) at hw/ide/core.c:1318
  #5  0x0000555555b1e3a1 in ide_bus_reset (bus=0x5555572132b8) at 
hw/ide/core.c:2422
  #6  0x0000555555b2aa27 in ahci_reset_port (s=0x55555720eb50, port=2) at 
hw/ide/ahci.c:650
  #7  0x0000555555b29fd7 in ahci_port_write (s=0x55555720eb50, port=2, 
offset=44, val=16) at hw/ide/ahci.c:360
  #8  0x0000555555b2a564 in ahci_mem_write (opaque=0x55555720eb50, addr=556, 
val=16, size=1) at hw/ide/ahci.c:513
  #9  0x000055555598415b in memory_region_write_accessor (mr=0x55555720eb80, 
addr=556, value=0x7fffffffb838, size=1, shift=0, mask=255, attrs=...) at 
softmmu/memory.c:483

Looking at bdrv_aio_cancel:

2728 /* async I/Os */
2729
2730 void bdrv_aio_cancel(BlockAIOCB *acb)
2731 {
2732     qemu_aio_ref(acb);
2733     bdrv_aio_cancel_async(acb);
2734     while (acb->refcnt > 1) {
2735         if (acb->aiocb_info->get_aio_context) {
2736             aio_poll(acb->aiocb_info->get_aio_context(acb), true);
2737         } else if (acb->bs) {
2738             /* qemu_aio_ref and qemu_aio_unref are not thread-safe, so
2739              * assert that we're not using an I/O thread.  Thread-safe
2740              * code should use bdrv_aio_cancel_async exclusively.
2741              */
2742             assert(bdrv_get_aio_context(acb->bs) == 
qemu_get_aio_context());
2743             aio_poll(bdrv_get_aio_context(acb->bs), true);
2744         } else {
2745             abort();     <===============
2746         }
2747     }
2748     qemu_aio_unref(acb);
2749 }

Fixes: 02c50efe08736116048d5fc355043080f4d5859c ("block: Add 
bdrv_aio_cancel_async")
Reported-by: Alexander Bulekov <alxndr@bu.edu>
Buglink: https://bugs.launchpad.net/qemu/+bug/1878255
Originally-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200720100141.129739-1-stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>


  Commit: 98d897eb4b6fb8c637b2b046e1c543bc5a9f2c4e
      
https://github.com/qemu/qemu/commit/98d897eb4b6fb8c637b2b046e1c543bc5a9f2c4e
  Author: Peter Maydell <peter.maydell@linaro.org>
  Date:   2020-07-21 (Tue, 21 Jul 2020)

  Changed paths:
    M block/block-backend.c
    M block/crypto.c
    M tests/qemu-iotests/296
    M tests/qemu-iotests/296.out

  Log Message:
  -----------
  Merge remote-tracking branch 'remotes/maxreitz/tags/pull-block-2020-07-21' 
into staging

Block patches for 5.1:
- Let LUKS images only be shared between VMs if the guest device was
  configured to allow that
- Fix abort() from bdrv_aio_cancel() for guest devices without a BDS

# gpg: Signature made Tue 21 Jul 2020 12:47:17 BST
# gpg:                using RSA key 91BEB60A30DB3E8857D11829F407DB0061D5CF40
# gpg:                issuer "mreitz@redhat.com"
# gpg: Good signature from "Max Reitz <mreitz@redhat.com>" [full]
# Primary key fingerprint: 91BE B60A 30DB 3E88 57D1  1829 F407 DB00 61D5 CF40

* remotes/maxreitz/tags/pull-block-2020-07-21:
  block: fix bdrv_aio_cancel() for ENOMEDIUM requests
  qemu-iotests: add testcase for bz #1857490
  block/crypto: disallow write sharing by default

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>


Compare: https://github.com/qemu/qemu/compare/90218a9a393c...98d897eb4b6f