Re: [PATCH v2] qtest/libqtest: fix heap-buffer-overflow in qtest_cb_for_every_machine()

[Thomas Huth <thuth@redhat.com>]

On 06/01/2021 06.06, Gan Qixin wrote:
> When the length of mname is less than 5, memcpy("xenfv", mname, 5) will cause
> heap buffer overflow. Therefore, use strncmp to avoid this problem.
> 
> The asan showed stack:
> 
> ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60200000f2f4 at
> pc 0x7f65d8cc2225 bp 0x7ffe93cc5a60 sp 0x7ffe93cc5208 READ of size 5 at
> 0x60200000f2f4 thread T0
>      #0 0x7f65d8cc2224 in memcmp (/lib64/libasan.so.5+0xdf224)
>      #1 0x5632c20be95b in qtest_cb_for_every_machine tests/qtest/libqtest.c:1282
>      #2 0x5632c20b7995 in main tests/qtest/test-hmp.c:160
>      #3 0x7f65d88fed42 in __libc_start_main (/lib64/libc.so.6+0x26d42)
>      #4 0x5632c20b72cd in _start (build/tests/qtest/test-hmp+0x542cd)
> 
> Reported-by: Euler Robot <euler.robot@huawei.com>
> Signed-off-by: Gan Qixin <ganqixin@huawei.com>
> ---
> Cc: Thomas Huth <thuth@redhat.com>
> Cc: Laurent Vivier <lvivier@redhat.com>
> 
> v2:
> Changes suggested by Thomas Huth:
>      Replace memcmp(..., 5) with strncmp(..., 5).
> ---
>   tests/qtest/libqtest.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Thanks, queued now to my qtest-next branch:

  https://gitlab.com/huth/qemu/-/commits/qtest-next/

  Thomas