From: Jaroslav Kysela <perex@perex.cz>
Date: Mon, 21 Jun 2021 13:14:18 +0000 (+0200)
Subject: pcm: direct plugins - fix bad memory access when channel bindings do not match hw
X-Git-Tag: v1.2.6~43
X-Git-Url: https://git.alsa-project.org/?a=commitdiff_plain;h=e0e084659083c2ab75d5c894f24227ea2f67010f;p=alsa-lib.git

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 d50503e3..90417b2f 100644
--- 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;
 }
 
 /*