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pcm: dshare: Fix segfault when not binding channel 0

Browse source 
Configuration to reproduce:

~~~~
pcm.share_right {
  type dshare
  ipc_key 73
  ipc_perm 0666
  slave {
    pcm "hw:0,0"
  }
  bindings {
    # the seagfault happens when we don't bind channel 0
    1 1
  }
}
~~~~

Execute to reproduce:

~~~~
$ aplay -D plug:share_right test.wav
Playing WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
Segmentation fault
~~~~

For channels whithout binding, values are set to UINT_MAX in function
`snd_pcm_direct_parse_bindings()`:

~~~~
	for (chn = 0; chn < count; chn++)
		bindings[chn] = UINT_MAX;		/* don't route */
~~~~

But, these values are not checked when playing, which causes the segfault.

This commit fixes the issue.

Signed-off-by: Kirill Marinushkin <kmarinushkin@birdec.tech>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Kirill Marinushkin 2018-11-20 21:43:44 +01:00 • committed by Takashi Iwai
parent 6b058fda9d
commit d3dfef24bf
1 changed files with 11 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

15
src/pcm/pcm_dshare.c
View file

@ -67,7 +67,9 @@ static void do_silence(snd_pcm_t *pcm)
format = dshare->shmptr->s.format;
for (chn = 0; chn < channels; chn++) {
dchn = dshare->bindings ? dshare->bindings[chn] : chn;
snd_pcm_area_silence(&dst_areas[dchn], 0, dshare->shmptr->s.buffer_size, format);
if (dchn != UINT_MAX)
snd_pcm_area_silence(&dst_areas[dchn], 0,
dshare->shmptr->s.buffer_size, format);
}
}
@ -91,7 +93,9 @@ static void share_areas(snd_pcm_direct_t *dshare,
} else {
for (chn = 0; chn < channels; chn++) {
dchn = dshare->bindings ? dshare->bindings[chn] : chn;
snd_pcm_area_copy(&dst_areas[dchn], dst_ofs, &src_areas[chn], src_ofs, size, format);
if (dchn != UINT_MAX)
snd_pcm_area_copy(&dst_areas[dchn], dst_ofs,
&src_areas[chn], src_ofs, size, format);
}
}
@ -834,8 +838,11 @@ int snd_pcm_dshare_open(snd_pcm_t **pcmp, const char *name,
dshare->spcm = spcm;
}
for (chn = 0; chn < dshare->channels; chn++)
dshare->u.dshare.chn_mask |= (1ULL<<dshare->bindings[chn]);
for (chn = 0; chn < dshare->channels; chn++) {
unsigned int dchn = dshare->bindings ? dshare->bindings[chn] : chn;
if (dchn != UINT_MAX)
dshare->u.dshare.chn_mask |= (1ULL << dchn);
}
if (dshare->shmptr->u.dshare.chn_mask & dshare->u.dshare.chn_mask) {
SNDERR("destination channel specified in bindings is already used");
dshare->u.dshare.chn_mask = 0;