Re: [PATCH] [v2] ALSA: core: fix buffer overflow in test_format_fill_silence()

Naresh Kamboju
2024-02-18T07:54:30Z

On Sat, 17 Feb 2024 at 16:13, Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> KASAN caught a buffer overflow with the hardcoded 2048 byte buffer
> size, when 2080 bytes are written to it:
>
> BUG: KASAN: slab-out-of-bounds in snd_pcm_format_set_silence+0x3bc/0x3e4
> Write of size 8 at addr ffff0000c8149800 by task kunit_try_catch/1297
>
> CPU: 0 PID: 1297 Comm: kunit_try_catch Tainted: G N 6.8.0-rc4-next-20240216 #1
> Hardware name: linux,dummy-virt (DT)
> Call trace:
> kasan_report+0x78/0xc0
> __asan_report_store_n_noabort+0x1c/0x28
> snd_pcm_format_set_silence+0x3bc/0x3e4
> _test_fill_silence+0xdc/0x298
> test_format_fill_silence+0x110/0x228
> kunit_try_run_case+0x144/0x3bc
> kunit_generic_run_threadfn_adapter+0x50/0x94
> kthread+0x330/0x3e8
> ret_from_fork+0x10/0x20
>
> Allocated by task 1297:
> __kmalloc+0x17c/0x2f0
> kunit_kmalloc_array+0x2c/0x78
> test_format_fill_silence+0xcc/0x228
> kunit_try_run_case+0x144/0x3bc
> kunit_generic_run_threadfn_adapter+0x50/0x94
> kthread+0x330/0x3e8
> ret_from_fork+0x10/0x20
>
> Replace the incorrect size with the correct length of 260 64-bit samples.
>
> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
> Suggested-by: Ivan Orlov <ivan.orlov0322@gmail.com>
> Fixes: 3e39acf56ede ("ALSA: core: Add sound core KUnit test")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>

> ---
> v2: use a named constant as suggested by Ivan Orlov
> ---
> sound/core/sound_kunit.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/sound/core/sound_kunit.c b/sound/core/sound_kunit.c
> index 5d5a7bf88de4..4212c4a20697 100644
> --- a/sound/core/sound_kunit.c
> +++ b/sound/core/sound_kunit.c
> @@ -8,7 +8,8 @@
> #include <sound/core.h>
> #include <sound/pcm.h>
>
> -#define SILENCE_BUFFER_SIZE 2048
> +#define SILENCE_BUFFER_MAX_FRAMES 260
> +#define SILENCE_BUFFER_SIZE (sizeof(u64) * SILENCE_BUFFER_MAX_FRAMES)
> #define SILENCE(...) { __VA_ARGS__ }
> #define DEFINE_FORMAT(fmt, pbits, wd, endianness, signd, silence_arr) { \
> .format = SNDRV_PCM_FORMAT_##fmt, .physical_bits = pbits, \
> @@ -165,7 +166,7 @@ static void _test_fill_silence(struct kunit *test, struct snd_format_test_data *
>
> static void test_format_fill_silence(struct kunit *test)
> {
> - u32 buf_samples[] = { 10, 20, 32, 64, 129, 260 };
> + u32 buf_samples[] = { 10, 20, 32, 64, 129, SILENCE_BUFFER_MAX_FRAMES };
> u8 *buffer;
> u32 i, j;
>
> --
> 2.39.2
>

--
Linaro LKFT