Re: [Qemu-devel] [PULL v3 1/3] replay: add record/replay for audio passthrough

[Peter Maydell]

On 1 March 2017 at 15:40, Gerd Hoffmann <address@hidden> wrote:
> From: Pavel Dovgalyuk <address@hidden>
>
> This patch adds recording and replaying audio data. Is saves synchronization
> information for audio out and inputs from the microphone.
>
> v2: removed unneeded whitespace change
>
> Signed-off-by: Pavel Dovgalyuk <address@hidden>
> Message-id: address@hidden
>
> [ kraxel: add qemu/error-report.h include to fix osx build failure ]
>
> Signed-off-by: Gerd Hoffmann <address@hidden>
> ---
>  audio/audio.c            |  9 ++++--
>  audio/audio.h            |  5 +++
>  audio/mixeng.c           | 32 ++++++++++++++++++++
>  docs/replay.txt          |  7 +++++
>  include/sysemu/replay.h  |  7 +++++
>  replay/Makefile.objs     |  1 +
>  replay/replay-audio.c    | 79 
> ++++++++++++++++++++++++++++++++++++++++++++++++
>  replay/replay-internal.h |  4 +++
>  8 files changed, 142 insertions(+), 2 deletions(-)
>  create mode 100644 replay/replay-audio.c
>
> diff --git a/audio/audio.c b/audio/audio.c
> index c845a44..21f7b0b 100644
> --- a/audio/audio.c
> +++ b/audio/audio.c
> @@ -28,6 +28,7 @@
>  #include "qemu/timer.h"
>  #include "sysemu/sysemu.h"
>  #include "qemu/cutils.h"
> +#include "sysemu/replay.h"
>
>  #define AUDIO_CAP "audio"
>  #include "audio_int.h"
> @@ -1387,6 +1388,7 @@ static void audio_run_out (AudioState *s)
>
>          prev_rpos = hw->rpos;
>          played = hw->pcm_ops->run_out (hw, live);
> +        replay_audio_out(&played);
>          if (audio_bug (AUDIO_FUNC, hw->rpos >= hw->samples)) {
>              dolog ("hw->rpos=%d hw->samples=%d played=%d\n",
>                     hw->rpos, hw->samples, played);

Hi. Coverity produces a new warning because of this change (CID1390632),
because it treats the replay file as "tainted data", and complains
that we trust a value from the file to become a sample count
passed to audio_capture_mix_and_clear() and eventually used as
a byte count for a memset.

Do we trust the replay file to be non-malicious (making this
a false-positive), or not (in which case we need to sanitize
or check its contents somehow) ?

thanks
-- PMM