On Wed, 11 Sep 2019 09:22:53 +0200, Peter Ujfalusi wrote:
On 10/09/2019 15.07, Takashi Iwai wrote:
On Fri, 06 Sep 2019 07:55:24 +0200, Peter Ujfalusi wrote:
Some tools use the snd_pcm_info_get_name() to try to identify PCMs or for other purposes.
Currently it is left empty with the dmaengine-pcm, in this case copy the pcm->id string as pcm->name.
For example IGT is using this to find the HDMI PCM for testing audio on it.
Signed-off-by: Peter Ujfalusi peter.ujfalusi@ti.com Reported-by: Arthur She arthur.she@linaro.org
Hi,
this was actually reported for 4.14 kernel with omap-pcm (replaced by sdma-pcm in v4.18), since then we only use the generic dmaengine PCM but the same issue applies today.
Regards, Peter
sound/soc/soc-generic-dmaengine-pcm.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c index 748f5f641002..d93db2c2b527 100644 --- a/sound/soc/soc-generic-dmaengine-pcm.c +++ b/sound/soc/soc-generic-dmaengine-pcm.c @@ -306,6 +306,12 @@ static int dmaengine_pcm_new(struct snd_soc_pcm_runtime *rtd)
if (!dmaengine_pcm_can_report_residue(dev, pcm->chan[i])) pcm->flags |= SND_DMAENGINE_PCM_FLAG_NO_RESIDUE;
if (rtd->pcm->streams[i].pcm->name[0] == '\0') {strncpy(rtd->pcm->streams[i].pcm->name,rtd->pcm->streams[i].pcm->id,sizeof(rtd->pcm->streams[i].pcm->name));}Any reason to use strncpy() instead of strscpy()? After merging Mark's branch, I got a compile warning like: sound/soc/soc-generic-dmaengine-pcm.c:311:4: warning: 'strncpy' accessing 80 bytes at offsets 88 and 24 may overlap up to 0 bytes at offset [9223372036854775807, -9223372036854775808] [-Wrestrict]
fwiw I run it again with sparse and it only reports these: CHECK sound/soc/soc-generic-dmaengine-pcm.c sound/soc/soc-generic-dmaengine-pcm.c:177:42: warning: restricted snd_pcm_format_t degrades to integer sound/soc/soc-generic-dmaengine-pcm.c:177:47: warning: restricted snd_pcm_format_t degrades to integer sound/soc/soc-generic-dmaengine-pcm.c:177:71: warning: restricted snd_pcm_format_t degrades to integer CC sound/soc/soc-generic-dmaengine-pcm.o
gcc 6.4.0...9.2.0 sparse 0.6.0
That happens only with some cross-build on my build tests, so it must be a pretty minor issue.
But in general, almost all strncpy() use case can be replaced gracefully with a safer function, either strscpy() or strscpy_pad(). IOW, if you see strncpy(), the patch looks doubtful :)
thanks,
Takashi
Takashi
return 0;
Peter
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