pcm: direct plugins - fix bad memory access when channel bindings do not match hw

Fix and cleanup snd_pcm_direct_check_interleave() function.
Add requested / hardware channel check and use goto when the interleaved

Fixes: https://github.com/alsa-project/alsa-lib/issues/117
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

diff --git a/src/pcm/pcm_direct.c b/src/pcm/pcm_direct.c
index d50503e3daf189258a8e4c9c65582b7e75092da5..90417b2f45d27bad8c00e35d2807b471ed249e58 100644 (file)
--- a/src/pcm/pcm_direct.c
+++ b/src/pcm/pcm_direct.c
@@ -1627,43 +1627,37 @@ int snd_pcm_direct_set_timer_params(snd_pcm_direct_t *dmix)
 int snd_pcm_direct_check_interleave(snd_pcm_direct_t *dmix, snd_pcm_t *pcm)
 {
        unsigned int chn, channels;
-       int bits, interleaved = 1;
+       int bits;
        const snd_pcm_channel_area_t *dst_areas;
        const snd_pcm_channel_area_t *src_areas;
 
        bits = snd_pcm_format_physical_width(pcm->format);
        if ((bits % 8) != 0)
-               interleaved = 0;
+               goto __nointerleaved;
        channels = dmix->channels;
+       if (channels != dmix->spcm->channels)
+               goto __nointerleaved;
        dst_areas = snd_pcm_mmap_areas(dmix->spcm);
        src_areas = snd_pcm_mmap_areas(pcm);
        for (chn = 1; chn < channels; chn++) {
-               if (dst_areas[chn-1].addr != dst_areas[chn].addr) {
-                       interleaved = 0;
-                       break;
-               }
-               if (src_areas[chn-1].addr != src_areas[chn].addr) {
-                       interleaved = 0;
-                       break;
-               }
+               if (dst_areas[chn-1].addr != dst_areas[chn].addr)
+                       goto __nointerleaved;
+               if (src_areas[chn-1].addr != src_areas[chn].addr)
+                       goto __nointerleaved;
        }
        for (chn = 0; chn < channels; chn++) {
-               if (dmix->bindings && dmix->bindings[chn] != chn) {
-                       interleaved = 0;
-                       break;
-               }
+               if (dmix->bindings && dmix->bindings[chn] != chn)
+                       goto __nointerleaved;
                if (dst_areas[chn].first != chn * bits ||
-                   dst_areas[chn].step != channels * bits) {
-                       interleaved = 0;
-                       break;
-               }
+                   dst_areas[chn].step != channels * bits)
+                       goto __nointerleaved;
                if (src_areas[chn].first != chn * bits ||
-                   src_areas[chn].step != channels * bits) {
-                       interleaved = 0;
-                       break;
-               }
+                   src_areas[chn].step != channels * bits)
+                       goto __nointerleaved;
        }
-       return dmix->interleaved = interleaved;
+       return dmix->interleaved = 1;
+__nointerleaved:
+       return dmix->interleaved = 0;
 }
 
 /*