pcm/Order: fix size calculation with 8 channels

This was a buffer overflow bug which could cause MPD crahes when playing back 8 channels with the ALSA output plugin. Closes #216

pcm/Order: fix size calculation with 8 channels
6de92bb4 · Max Kellermann · c801936e · 6de92bb4 · 6de92bb4
Commit 6de92bb4 authored Feb 09, 2018 by Max Kellermann
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NEWS NEWS +2 -0

Order.cxx src/pcm/Order.cxx +1 -1

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--- a/NEWS
+++ b/NEWS
 ver 0.20.17 (not yet released)
+* output
+  - alsa: fix crash bug with 8 channels
 * fix real-time and idle scheduling with Musl

 ver 0.20.16 (2018/02/03)

--- a/src/pcm/Order.cxx
+++ b/src/pcm/Order.cxx
@@ -88,7 +88,7 @@ static inline ConstBuffer<V>
 ToAlsaChannelOrder71(PcmBuffer &buffer, ConstBuffer<V> src)
 {
 	auto dest = buffer.GetT<V>(src.size);
-	ToAlsaChannelOrder71(dest, src.data, src.size / 6);
+	ToAlsaChannelOrder71(dest, src.data, src.size / 8);
 	return { dest, src.size };
 }