[OMPT-svn-commit] OpenMPT r22478 - trunk/OpenMPT/soundlib

[<sv...@op...>]

Author: sagamusix
Date: Fri Dec  6 19:07:14 2024
New Revision: 22478
URL: https://source.openmpt.org/browse/openmpt/?op=revision&rev=22478

Log:
[Fix] XM: In non-compatible linear slide mode, avoid shifting the period by arbitrary bit amounts if the period is extremely high. This caused the frequency to wrap around, which should not happen in non-compatible mode. Found with afl++ + ubsan.

Modified:
   trunk/OpenMPT/soundlib/Snd_fx.cpp

Modified: trunk/OpenMPT/soundlib/Snd_fx.cpp
==============================================================================
--- trunk/OpenMPT/soundlib/Snd_fx.cpp	Fri Dec  6 17:04:29 2024	(r22477)
+++ trunk/OpenMPT/soundlib/Snd_fx.cpp	Fri Dec  6 19:07:14 2024	(r22478)
@@ -6481,6 +6481,8 @@
 				octave = ((14 - div) & 0x1F);
 			} else
 			{
+				if(period > 29 * 768)
+					return 0;
 				octave = (period / 768) + 2;
 			}
 			return (XMLinearTable[period % 768] << (FREQ_FRACBITS + 2)) >> octave;