audiofile: add security patch for CVE-2017-6830 / CVE-2017-6834 / CVE-2017-6836 / CVE-2017-6838

CVE-2017-6830: A heap-based buffer overflow in the alaw2linear_buf function
in G711.cpp in Audio File Library (aka audiofile) 0.3.6 allows remote
attackers to cause a denial of service (crash) via a crafted file.

https://blogs.gentoo.org/ago/2017/02/20/audiofile-heap-based-buffer-overflow-in-alaw2linear_buf-g711-cpp
https://github.com/mpruett/audiofile/issues/34

CVE-2017-6834: A heap-based buffer overflow in the ulaw2linear_buf function
in G711.cpp in Audio File Library (aka audiofile) 0.3.6 allows remote
attackers to cause a denial of service (crash) via a crafted file.

https://blogs.gentoo.org/ago/2017/02/20/audiofile-heap-based-buffer-overflow-in-ulaw2linear_buf-g711-cpp
https://github.com/mpruett/audiofile/issues/38

CVE-2017-6836: A heap-based buffer overflow in the Expand3To4Module::run
function in libaudiofile/modules/SimpleModule.h in Audio File Library (aka
audiofile) 0.3.6 allows remote attackers to cause a denial of service
(crash) via a crafted file.

https://blogs.gentoo.org/ago/2017/02/20/audiofile-heap-based-buffer-overflow-in-expand3to4modulerun-simplemodule-h
https://github.com/mpruett/audiofile/issues/40

CVE-2017-6838: Integer overflow in sfcommands/sfconvert.c in Audio File
Library (aka audiofile) 0.3.6 allows remote attackers to cause a denial of
service (crash) via a crafted file.

https://blogs.gentoo.org/ago/2017/02/20/audiofile-multiple-ubsan-crashes/
https://github.com/mpruett/audiofile/issues/41

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/audiofile/0005-Check-for-multiplication-overflow-in-sfconvert.patch

@@ -0,0 +1,72 @@
+From 7d65f89defb092b63bcbc5d98349fb222ca73b3c Mon Sep 17 00:00:00 2001
+From: Antonio Larrosa <larrosa@kde.org>
+Date: Mon, 6 Mar 2017 13:54:52 +0100
+Subject: [PATCH] Check for multiplication overflow in sfconvert
+
+Checks that a multiplication doesn't overflow when
+calculating the buffer size, and if it overflows,
+reduce the buffer size instead of failing.
+
+This fixes the 00192-audiofile-signintoverflow-sfconvert case
+in #41
+
+Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
+---
+ sfcommands/sfconvert.c | 34 ++++++++++++++++++++++++++++++++--
+ 1 file changed, 32 insertions(+), 2 deletions(-)
+
+diff --git a/sfcommands/sfconvert.c b/sfcommands/sfconvert.c
+index 80a1bc4..970a3e4 100644
+--- a/sfcommands/sfconvert.c
++++ b/sfcommands/sfconvert.c
+@@ -45,6 +45,33 @@ void printusage (void);
+ void usageerror (void);
+ bool copyaudiodata (AFfilehandle infile, AFfilehandle outfile, int trackid);
+ 
++int firstBitSet(int x)
++{
++        int position=0;
++        while (x!=0)
++        {
++                x>>=1;
++                ++position;
++        }
++        return position;
++}
++
++#ifndef __has_builtin
++#define __has_builtin(x) 0
++#endif
++
++int multiplyCheckOverflow(int a, int b, int *result)
++{
++#if (defined __GNUC__ && __GNUC__ >= 5) || ( __clang__ && __has_builtin(__builtin_mul_overflow))
++	return __builtin_mul_overflow(a, b, result);
++#else
++	if (firstBitSet(a)+firstBitSet(b)>31) // int is signed, so we can't use 32 bits
++		return true;
++	*result = a * b;
++	return false;
++#endif
++}
++
+ int main (int argc, char **argv)
+ {
+ 	if (argc == 2)
+@@ -323,8 +350,11 @@ bool copyaudiodata (AFfilehandle infile, AFfilehandle outfile, int trackid)
+ {
+ 	int frameSize = afGetVirtualFrameSize(infile, trackid, 1);
+ 
+-	const int kBufferFrameCount = 65536;
+-	void *buffer = malloc(kBufferFrameCount * frameSize);
++	int kBufferFrameCount = 65536;
++	int bufferSize;
++	while (multiplyCheckOverflow(kBufferFrameCount, frameSize, &bufferSize))
++		kBufferFrameCount /= 2;
++	void *buffer = malloc(bufferSize);
+ 
+ 	AFframecount totalFrames = afGetFrameCount(infile, AF_DEFAULT_TRACK);
+ 	AFframecount totalFramesWritten = 0;
+-- 
+2.11.0
+