There is an overflow, the source 'datain.data[2]' is 100 bytes,
but the 'ss' is 252 bytes.This may cause a security issue because
we can access a lot of unrelated memory data.
The len for sbp copy data should take the minimum of mx_sb_len and
sb_len_wr, not the maximum.
If we use iscsi device for VM backend storage, ASAN show stack:
READ of size 252 at 0xfffd149dcfc4 thread T0
#0 0xaaad433d0d34 in __asan_memcpy (aarch64-softmmu/qemu-system-aarch64+0x2cb0d34)
#1 0xaaad45f9d6d0 in iscsi_aio_ioctl_cb /qemu/block/iscsi.c:996:9
#2 0xfffd1af0e2dc (/usr/lib64/iscsi/libiscsi.so.8+0xe2dc)
#3 0xfffd1af0d174 (/usr/lib64/iscsi/libiscsi.so.8+0xd174)
#4 0xfffd1af19fac (/usr/lib64/iscsi/libiscsi.so.8+0x19fac)
#5 0xaaad45f9acc8 in iscsi_process_read /qemu/block/iscsi.c:403:5
#6 0xaaad4623733c in aio_dispatch_handler /qemu/util/aio-posix.c:467:9
#7 0xaaad4622f350 in aio_dispatch_handlers /qemu/util/aio-posix.c:510:20
#8 0xaaad4622f350 in aio_dispatch /qemu/util/aio-posix.c:520
#9 0xaaad46215944 in aio_ctx_dispatch /qemu/util/async.c:298:5
#10 0xfffd1bed12f4 in g_main_context_dispatch (/lib64/libglib-2.0.so.0+0x512f4)
#11 0xaaad46227de0 in glib_pollfds_poll /qemu/util/main-loop.c:219:9
#12 0xaaad46227de0 in os_host_main_loop_wait /qemu/util/main-loop.c:242
#13 0xaaad46227de0 in main_loop_wait /qemu/util/main-loop.c:518
#14 0xaaad43d9d60c in qemu_main_loop /qemu/softmmu/vl.c:1662:9
#15 0xaaad4607a5b0 in main /qemu/softmmu/main.c:49:5
#16 0xfffd1a460b9c in __libc_start_main (/lib64/libc.so.6+0x20b9c)
#17 0xaaad43320740 in _start (aarch64-softmmu/qemu-system-aarch64+0x2c00740)
0xfffd149dcfc4 is located 0 bytes to the right of 100-byte region [0xfffd149dcf60,0xfffd149dcfc4)
allocated by thread T0 here:
#0 0xaaad433d1e70 in __interceptor_malloc (aarch64-softmmu/qemu-system-aarch64+0x2cb1e70)
#1 0xfffd1af0e254 (/usr/lib64/iscsi/libiscsi.so.8+0xe254)
#2 0xfffd1af0d174 (/usr/lib64/iscsi/libiscsi.so.8+0xd174)
#3 0xfffd1af19fac (/usr/lib64/iscsi/libiscsi.so.8+0x19fac)
#4 0xaaad45f9acc8 in iscsi_process_read /qemu/block/iscsi.c:403:5
#5 0xaaad4623733c in aio_dispatch_handler /qemu/util/aio-posix.c:467:9
#6 0xaaad4622f350 in aio_dispatch_handlers /qemu/util/aio-posix.c:510:20
#7 0xaaad4622f350 in aio_dispatch /qemu/util/aio-posix.c:520
#8 0xaaad46215944 in aio_ctx_dispatch /qemu/util/async.c:298:5
#9 0xfffd1bed12f4 in g_main_context_dispatch (/lib64/libglib-2.0.so.0+0x512f4)
#10 0xaaad46227de0 in glib_pollfds_poll /qemu/util/main-loop.c:219:9
#11 0xaaad46227de0 in os_host_main_loop_wait /qemu/util/main-loop.c:242
#12 0xaaad46227de0 in main_loop_wait /qemu/util/main-loop.c:518
#13 0xaaad43d9d60c in qemu_main_loop /qemu/softmmu/vl.c:1662:9
#14 0xaaad4607a5b0 in main /qemu/softmmu/main.c:49:5
#15 0xfffd1a460b9c in __libc_start_main (/lib64/libc.so.6+0x20b9c)
#16 0xaaad43320740 in _start (aarch64-softmmu/qemu-system-aarch64+0x2c00740)
Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200418062602.10776-1-kuhn.chenqun@huawei.com
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
===========
QEMU README
===========
QEMU is a generic and open source machine & userspace emulator and
virtualizer.
QEMU is capable of emulating a complete machine in software without any
need for hardware virtualization support. By using dynamic translation,
it achieves very good performance. QEMU can also integrate with the Xen
and KVM hypervisors to provide emulated hardware while allowing the
hypervisor to manage the CPU. With hypervisor support, QEMU can achieve
near native performance for CPUs. When QEMU emulates CPUs directly it is
capable of running operating systems made for one machine (e.g. an ARMv7
board) on a different machine (e.g. an x86_64 PC board).
QEMU is also capable of providing userspace API virtualization for Linux
and BSD kernel interfaces. This allows binaries compiled against one
architecture ABI (e.g. the Linux PPC64 ABI) to be run on a host using a
different architecture ABI (e.g. the Linux x86_64 ABI). This does not
involve any hardware emulation, simply CPU and syscall emulation.
QEMU aims to fit into a variety of use cases. It can be invoked directly
by users wishing to have full control over its behaviour and settings.
It also aims to facilitate integration into higher level management
layers, by providing a stable command line interface and monitor API.
It is commonly invoked indirectly via the libvirt library when using
open source applications such as oVirt, OpenStack and virt-manager.
QEMU as a whole is released under the GNU General Public License,
version 2. For full licensing details, consult the LICENSE file.
Building
========
QEMU is multi-platform software intended to be buildable on all modern
Linux platforms, OS-X, Win32 (via the Mingw64 toolchain) and a variety
of other UNIX targets. The simple steps to build QEMU are:
.. code-block:: shell
mkdir build
cd build
../configure
make
Additional information can also be found online via the QEMU website:
* `<https://qemu.org/Hosts/Linux>`_
* `<https://qemu.org/Hosts/Mac>`_
* `<https://qemu.org/Hosts/W32>`_
Submitting patches
==================
The QEMU source code is maintained under the GIT version control system.
.. code-block:: shell
git clone https://git.qemu.org/git/qemu.git
When submitting patches, one common approach is to use 'git
format-patch' and/or 'git send-email' to format & send the mail to the
qemu-devel@nongnu.org mailing list. All patches submitted must contain
a 'Signed-off-by' line from the author. Patches should follow the
guidelines set out in the CODING_STYLE.rst file.
Additional information on submitting patches can be found online via
the QEMU website
* `<https://qemu.org/Contribute/SubmitAPatch>`_
* `<https://qemu.org/Contribute/TrivialPatches>`_
The QEMU website is also maintained under source control.
.. code-block:: shell
git clone https://git.qemu.org/git/qemu-web.git
* `<https://www.qemu.org/2017/02/04/the-new-qemu-website-is-up/>`_
A 'git-publish' utility was created to make above process less
cumbersome, and is highly recommended for making regular contributions,
or even just for sending consecutive patch series revisions. It also
requires a working 'git send-email' setup, and by default doesn't
automate everything, so you may want to go through the above steps
manually for once.
For installation instructions, please go to
* `<https://github.com/stefanha/git-publish>`_
The workflow with 'git-publish' is:
.. code-block:: shell
$ git checkout master -b my-feature
$ # work on new commits, add your 'Signed-off-by' lines to each
$ git publish
Your patch series will be sent and tagged as my-feature-v1 if you need to refer
back to it in the future.
Sending v2:
.. code-block:: shell
$ git checkout my-feature # same topic branch
$ # making changes to the commits (using 'git rebase', for example)
$ git publish
Your patch series will be sent with 'v2' tag in the subject and the git tip
will be tagged as my-feature-v2.
Bug reporting
=============
The QEMU project uses Launchpad as its primary upstream bug tracker. Bugs
found when running code built from QEMU git or upstream released sources
should be reported via:
* `<https://bugs.launchpad.net/qemu/>`_
If using QEMU via an operating system vendor pre-built binary package, it
is preferable to report bugs to the vendor's own bug tracker first. If
the bug is also known to affect latest upstream code, it can also be
reported via launchpad.
For additional information on bug reporting consult:
* `<https://qemu.org/Contribute/ReportABug>`_
Contact
=======
The QEMU community can be contacted in a number of ways, with the two
main methods being email and IRC
* `<mailto:qemu-devel@nongnu.org>`_
* `<https://lists.nongnu.org/mailman/listinfo/qemu-devel>`_
* #qemu on irc.oftc.net
Information on additional methods of contacting the community can be
found online via the QEMU website:
* `<https://qemu.org/Contribute/StartHere>`_