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Re: [PATCH-for-6.2 v3 2/2] tests/qtest/fdc-test: Add a regression test f
Re: [PATCH-for-6.2 v3 2/2] tests/qtest/fdc-test: Add a regression test for CVE-2021-20196
Tue, 23 Nov 2021 14:49:12 +0100
Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.3.0
On 11/23/21 14:42, Hanna Reitz wrote:
> On 18.11.21 13:06, Philippe Mathieu-Daudé wrote:
>> From: Alexander Bulekov <firstname.lastname@example.org>
>> Without the previous commit, when running 'make check-qtest-i386'
>> with QEMU configured with '--enable-sanitizers' we get:
>> ==287878==ERROR: AddressSanitizer: SEGV on unknown address
>> ==287878==The signal is caused by a WRITE memory access.
>> ==287878==Hint: address points to the zero page.
>> #0 0x564b2e5bac27 in blk_inc_in_flight
>> #1 0x564b2e5bb228 in blk_pwritev_part block/block-backend.c:1317:5
>> #2 0x564b2e5bcd57 in blk_pwrite block/block-backend.c:1498:11
>> #3 0x564b2ca1cdd3 in fdctrl_write_data hw/block/fdc.c:2221:17
>> #4 0x564b2ca1b2f7 in fdctrl_write hw/block/fdc.c:829:9
>> #5 0x564b2dc49503 in portio_write softmmu/ioport.c:201:9
>> Add the reproducer for CVE-2021-20196.
>> Signed-off-by: Alexander Bulekov <email@example.com>
>> Message-Id: <firstname.lastname@example.org>
>> [PMD: Rebased, use global test_image]
>> Reviewed-by: Darren Kenny <email@example.com>
>> Signed-off-by: Philippe Mathieu-Daudé <firstname.lastname@example.org>
>> tests/qtest/fdc-test.c | 21 +++++++++++++++++++++
>> 1 file changed, 21 insertions(+)
> Not sure if I’m doing something wrong, but:
> Using the global test_image brings a problem, namely that this test
> fails unconditionally (for me at least...?), with the reason being that
> the global QEMU instance (launched by qtest_start(), quit by
> qtest_end()) still has that image open, so by launching a second
> instance concurrently, I get this:
> qemu-system-x86_64: Failed to get "write" lock
> Is another process using the image [/tmp/qtest.xV4IxX]?
Hmm I had too many odd problems running qtests in parallel so I
switched to 'make check-qtest -j1' more than 1 year ago, which
is probably why I haven't noticed that issue.
Using another 'test_image' seems against code reuse principle,
but at this point in release, duplicating it is simpler. Someone
will clean that later =)
> So either we need to use a different image file, or we need to quit the
> global instance before using it (e.g. putting a qtest_end() at the
> beginning of test_cve_*()), although the latter just seems wrong.
> Second, I can’t make this test fail. When I apply this patch first (to
> master) and run it, I don’t get a SIGSEGV.
Is your QEMU built with --enable-sanitizers ?
Re: [PATCH-for-6.2 v3 0/2] hw/block/fdc: Fix CVE-2021-20196, Philippe Mathieu-Daudé, 2021/11/22