audiofile/patches/audiofile-0.3.6-Check-for-multiplication-overflow-in-sfconvert.patch

From: Antonio Larrosa <larrosa@kde.org>
Date: Mon, 6 Mar 2017 13:54:52 +0100
Subject: 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
---
 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;
1	From: Antonio Larrosa <larrosa@kde.org>
2	Date: Mon, 6 Mar 2017 13:54:52 +0100
3	Subject: Check for multiplication overflow in sfconvert
4
5	Checks that a multiplication doesn't overflow when
6	calculating the buffer size, and if it overflows,
7	reduce the buffer size instead of failing.
8
9	This fixes the 00192-audiofile-signintoverflow-sfconvert case
10	in #41
11	---
12	sfcommands/sfconvert.c \| 34 ++++++++++++++++++++++++++++++++--
13	1 file changed, 32 insertions(+), 2 deletions(-)
14
15	diff --git a/sfcommands/sfconvert.c b/sfcommands/sfconvert.c
16	index 80a1bc4..970a3e4 100644
17	--- a/sfcommands/sfconvert.c
18	+++ b/sfcommands/sfconvert.c
19	@@ -45,6 +45,33 @@ void printusage (void);
20	void usageerror (void);
21	bool copyaudiodata (AFfilehandle infile, AFfilehandle outfile, int trackid);
22
23	+int firstBitSet(int x)
24	+{
25	+ int position=0;
26	+ while (x!=0)
27	+ {
28	+ x>>=1;
29	+ ++position;
30	+ }
31	+ return position;
32	+}
33	+
34	+#ifndef __has_builtin
35	+#define __has_builtin(x) 0
36	+#endif
37	+
38	+int multiplyCheckOverflow(int a, int b, int *result)
39	+{
40	+#if (defined __GNUC__ && __GNUC__ >= 5) \|\| ( __clang__ && __has_builtin(__builtin_mul_overflow))
41	+ return __builtin_mul_overflow(a, b, result);
42	+#else
43	+ if (firstBitSet(a)+firstBitSet(b)>31) // int is signed, so we can't use 32 bits
44	+ return true;
45	+ result = a b;
46	+ return false;
47	+#endif
48	+}
49	+
50	int main (int argc, char **argv)
51	{
52	if (argc == 2)
53	@@ -323,8 +350,11 @@ bool copyaudiodata (AFfilehandle infile, AFfilehandle outfile, int trackid)
54	{
55	int frameSize = afGetVirtualFrameSize(infile, trackid, 1);
56
57	- const int kBufferFrameCount = 65536;
58	- void buffer = malloc(kBufferFrameCount frameSize);
59	+ int kBufferFrameCount = 65536;
60	+ int bufferSize;
61	+ while (multiplyCheckOverflow(kBufferFrameCount, frameSize, &bufferSize))
62	+ kBufferFrameCount /= 2;
63	+ void *buffer = malloc(bufferSize);
64
65	AFframecount totalFrames = afGetFrameCount(infile, AF_DEFAULT_TRACK);
66	AFframecount totalFramesWritten = 0;